TWI821855B - Manufacturing method and display device of laminated film, laminated body, polarizing plate, polarizing plate roll - Google Patents

Abstract

An object of the present invention is to provide a laminated film that is excellent in impact resistance when bonded to a glass plate, adhesion durability under high temperature and high humidity, durability against repeated folding operations, and non-occurrence of optical unevenness. Furthermore, a laminated body in which a glass plate and the laminated film are laminated together, a polarizing plate provided with the laminated film or the laminated body, a manufacturing method of the polarizing plate roll material, and a display device equipped with the polarizing plate are provided. The laminated film of the present invention is a laminated film composed of at least an optical film, an adhesive layer and a release film, and is characterized in that the film thickness of the optical film is 1 to less than 10 μm, and the film thickness of the adhesive layer is 1 to 10 μm. Less than 10μm.

Description

Manufacturing method and display device of laminated film, laminated body, polarizing plate, polarizing plate roll

The present invention relates to a manufacturing method of a laminated film, a laminated body, a polarizing plate, a polarizing plate roll, and a display device. More specifically, when bonded to a flexible thin glass plate, it has excellent impact resistance and bonding durability under high temperature and high humidity, durability against repeated folding movements, and no optical unevenness. Laminated films, etc.

Recently, foldable flexible displays have attracted attention. As organic EL displays that do not require backlight, unlike liquid crystal displays, are on the market, interest in foldable flexible displays has increased and development is underway. In order to provide the folding function, the components included in the flexible display are required to be further thinned, and the polarizing plate and the outermost layer (covering layer) are no exception.

Generally speaking, polarizing plates are manufactured by laminating optical films and polarizing sub-layers as polarizing plate rolls with an adhesive layer laminated on them, and then suitably formed into appropriate shapes and mounted on the display substrate. Therefore, if flexibility is also considered in polarizing plates, in addition to the uniformity of physical properties such as the thickness of the optical film, impact resistance including folding operations is also newly required, and repeated folding operations even under high temperatures and high humidity are required. , and no optical unevenness will occur. Although unevenness is mainly caused by the inner layer of the polarizing plate, since it affects the visual visibility when wearing polarized sunglasses, the outer layer of the polarizer is also required to have stable characteristics.

In addition, glass is suitably used for display substrates, and with recent thinning, glass films are increasingly used. However, generally speaking, the thinner the glass, the less impact-resistant it is and will easily break. Therefore, a laminate in which a glass film and a polarizing plate are bonded together as a display substrate of a flexible display is also required to have impact resistance including folding action.

Furthermore, Patent Document 1 considers the "uneven phenomenon" in an optical laminate having a structure in which a glass plate and a resin optical film are bonded together via an adhesive, due to the glass plate, which has not been taken seriously in the past. Refraction is improved by using an adhesive with a value that exhibits intrinsic birefringence, which offsets the photoelasticity of the glass plate. However, this technology does not take into account the optical unevenness caused by repeated folding movements that are unique to portable flexible displays, such as outdoor high temperatures and high humidity, and is therefore suitable for the design of improving the impact resistance of glass, which cannot satisfy the new market. Require. Prior art documents Patent documents

[Patent Document 1] Japanese Invention Patent No. 6550576

[Problem to be solved by the invention]

The present invention was completed in view of the above-mentioned problems and situations, and the problem to be solved is to provide a laminated film that has impact resistance when bonded to a glass plate, adhesion durability under high temperature and high humidity, and durability and durability against repeated folding operations. Excellent resistance to optical unevenness. Furthermore, a laminated body in which a glass plate and the laminated film are laminated together, a polarizing plate provided with the laminated film or the laminated body, a manufacturing method of the polarizing plate roll material, and a display device equipped with the polarizing plate are provided. [Means to solve the problem]

In order to solve the above-mentioned problems, the inventors of the present invention discovered in the process of examining the causes of the above-mentioned problems that a laminated film composed of an optical film of a specific thickness and an adhesive layer can be obtained. In particular, by making the adhesive layer The thickness is thinner than before, and the invention is achieved by having excellent impact resistance when bonded to a glass plate, bonding durability under high temperature and high humidity, durability against repeated folding movements, and no optical unevenness.

That is, the above-mentioned problems of the present invention are solved by the following means.

1. A laminated film consisting of at least an optical film, an adhesive layer and a release film, characterized by: The film thickness of the aforementioned optical film is 1 to less than 10 μm, and the film thickness of the aforementioned adhesive layer is 1 to less than 10 μm.

2. The laminated film according to item 1, wherein the film thickness of the optical film satisfies the following formula 1; Formula 1: 5＜｜The average value of the thickness of three arbitrarily selected points in the width direction (B) - average film thickness value (A) |/average film thickness value (A) × 100＜20.

3. The laminated film described in Item 1 or 2, wherein the water vapor transmittance of the aforementioned optical film is in the range of 500~3000g/ ^m2 ·day at a temperature of 40°C and a humidity of 90%RH.

4. The laminated film according to any one of items 1 to 3, wherein the content of rubber particles in the optical film is in the range of 40 to 85% by mass relative to the optical film.

5. The laminated film according to any one of items 1 to 4, wherein the adhesive force to the substrate is 3.0 N/25mm or more when the release film is peeled off and the substrate is bonded through the adhesive layer.

6. The laminated film as described in any one of items 1 to 5, wherein the adhesive layer is for glass.

7. The laminated film as described in any one of items 1 to 6, wherein the water vapor transmission rate of the aforementioned adhesive layer is between 800 and 5000 g/m ² ·day at a temperature of 40°C and a humidity of 90%RH. within the range.

8. The laminated film according to any one of items 1 to 7, wherein the water vapor transmittance of the adhesive layer is higher than the water vapor transmittance of the optical film.

9. A laminated body, characterized in that the laminated film and the glass plate according to any one of items 1 to 8 are bonded together through the adhesive layer.

10. A polarizing plate characterized by having the laminated film or laminated body according to any one of items 1 to 9.

11. A method of manufacturing a polarizing plate roll, which is a manufacturing method of a polarizing plate roll manufactured through the following steps: A laminating step of laminating polarizers to produce a polarizing plate on the side of the optical film of a laminated film composed of at least an optical film, an adhesive layer and a release film, and a winding step of winding up the polarizing plate; It is characterized in that: the film thickness of the aforementioned adhesive layer is 1 μm to less than 10 μm, and the film thickness of the optical film is 1 μm to less than 10 μm.

12. The method for manufacturing a polarizing plate roll as described in Item 11, wherein the release film is rolled up without peeling off the release film in an intermediate step.

13. The manufacturing method of a polarizing plate roll as described in Item 11 or 12, wherein the aforementioned polarizing plate roll is composed of at least the aforementioned release film, the aforementioned adhesive layer, the aforementioned optical film, and the aforementioned polarizer.

14. A display device, characterized in that the thickness of the substrate is in the range of 10 to 100 μm, and the display device is provided with the polarizing plate according to item 10. [Effects of the invention]

By the above-mentioned means of the present invention, it is possible to provide a laminated film that is excellent in impact resistance when bonded to a glass plate and bonding durability under high temperature and high humidity, durability against repeated folding operations, and characteristics that do not cause optical unevenness. . Furthermore, it is possible to provide a laminated body in which a glass plate and the laminated film are laminated together, a polarizing plate provided with the laminated film or the laminated body, a manufacturing method of the polarizing plate roll material, and a display device provided with the polarizing plate.

Although the mechanism by which the effects of the present invention are exhibited or acted upon is not clear, it is presumed as follows.

The present invention is a laminated film composed of an optical film, an adhesive layer, and a release film, and is characterized in that the film thickness (also referred to as "thickness") of the optical film and the adhesive layer is within a certain range.

With this feature, a laminated film can be obtained that is excellent in impact resistance when bonded to a glass plate and bonding durability under high temperature and high humidity, durability against repeated folding operations, and characteristics that do not cause optical unevenness.

In the past, as for the adhesive layer, attention was paid to the adhesion (or adhesion) of dissimilar materials to each other and the function of mitigating the shrinkage of dissimilar materials to each other. Therefore, the design was generally carried out to ensure the thickness of the adhesive layer to ensure both functions. Therefore, as displays become thinner, other components become thinner, but on the other hand, there is little progress in further thinning the adhesive layer (film).

However, in the recent development of flexible displays, the previous adhesive layer has a problem of reduced adhesion due to repeated folding movements. In addition, recent glass substrates are thinner and mounted on flexible displays. However, compared with conventional glass substrates, there is a problem that they are easily damaged, that is, impact resistance becomes an issue.

That is, as the glass substrate becomes thinner, the glass substrate naturally becomes fragile. Of course, these are caused by the physical changes of the glass substrate with the load. The adhesive layer in contact with the glass substrate here is thicker than the conventional design film thickness and is not flexible, so it cannot suppress the physical changes. As a result, it is It is considered that there is a problem of weak impact resistance. In addition, it is believed that the deterioration of the adhesion between the adhesive layer and the physically changing substrate causes durability problems of the display device. Regarding this issue, the inventors conducted detailed investigations such as factor isolation in the previous manufacturing process, and found that in order to make it impact-resistant, in addition to thinning the adhesive layer and the thickness of the optical film that provides the adhesive layer, there is also a need to define This problem can be solved in the step of providing an adhesive layer. When this glass substrate is made into a thin film or a foldable ultra-thin film, the thickness of the adhesive layer is deliberately reduced so that the distance between the optical film such as the polarizer and the rigid glass substrate is close, and the adhesion between the layers is improved, and it is speculated that it can Confers impact resistance.

Furthermore, consider the respective layers when a laminated body having an optical film, an adhesive layer, and a glass plate in this order is repeatedly folded. When the glass plate is folded to the inside, the adhesive layer and optical film are stretched and folded along with the movement of the glass plate. At this time, the thicker the adhesive layer of the optical film is, the more it is stretched. On the contrary, when the glass plate is folded to the outside, the adhesive layer and optical film are compressed and folded along with the movement of the glass plate. At this time, the thicker the adhesive layer of the optical film is, the more compressed it is.

Generally speaking, the resin used for the optical film has higher elasticity than the glass plate, so by repeating such folding action, the optical film repeatedly expands and contracts. Furthermore, it is thought that optical unevenness may occur as the optical film becomes bulged due to progressive poor adhesion. In addition, since stress is concentrated on the folded portion of the glass plate, it is considered that the glass plate is easily damaged. Furthermore, since the thermal expansion coefficient and humidity expansion coefficient of the glass plate and resin are different, adhesion failure is particularly likely to occur in high-temperature and high-humidity environments. It is believed that optical unevenness is also likely to occur.

Moreover, by reducing the thickness of the optical film and the adhesive layer of the present invention to a certain range, the expansion and contraction of the optical film due to the folding operation is reduced, and it is presumed that the occurrence of optical unevenness can be suppressed. In addition, the stress exerted on the glass plate is reduced, and it is presumed that it is less likely to be damaged.

[Form of carrying out the invention]

The laminated film of the present invention is a laminated film composed of at least an optical film, an adhesive layer and a release film, and is characterized in that the film thickness of the optical film is 1 to less than 10 μm, and the film thickness of the adhesive layer is 1 to 10 μm. Less than 10μm. This feature is a technical feature common to or corresponding to the following embodiments.

As an embodiment of the present invention, from the viewpoint of exhibiting the effects of the present invention, the film thickness of the optical film is preferably such that it satisfies the following formula 1. Formula 1: 5＜｜The average value of the thickness of three arbitrarily selected points in the width direction (B) - average film thickness value (A) |/average film thickness value (A) × 100＜20. It is preferable from the viewpoint of improving the adhesion with the upper layer that the surface has moderate unevenness.

In addition, the water vapor transmittance of the aforementioned optical film is in the range of 500 to 3000 g/m ² ·day at a temperature of 40°C and a humidity of 90% RH, from the bonding layer formed when the optical film and the polarizing sub-layer are bonded. It is preferable from a durability point of view. By setting the moisture permeability of the optical film to 500g/ ^m2 ·day or more, the moisture and solvent contained in the adhesive layer can easily diffuse to the optical film side, thereby improving the durability of the adhesive layer. On the other hand, by setting it to 3000g/ ^m2 ·day or less, the optical film is less likely to absorb moisture and swell, and has excellent adhesion durability against dimensional changes, etc.

Furthermore, the content of the rubber particles in the optical film is preferably in the range of 40 to 85% by mass relative to the optical film, from the viewpoint of imparting toughness (flexibility) and improving crease resistance.

When the release film is peeled off and the substrate is bonded through the adhesive layer, it is preferable from the viewpoint of the adhesion between the optical film and the glass plate that the adhesive force of the substrate is 3.0N/25mm or more.

The adhesive layer is preferably made of glass from the viewpoint of adhesion with the glass substrate.

The water vapor transmittance of the aforementioned adhesive layer is in the range of 800~5000g/ ^m2 ·day at a temperature of 40°C and a humidity of 90% RH. From the durability of the adhesive layer formed when the optical film and the polarizing sub-layer are bonded, From this point of view, it is more appropriate. By setting the moisture permeability of the adhesive layer to 800g/ ^m2 ·day or more, the moisture and solvent contained in the adhesive layer can easily diffuse from the optical film side to the adhesive layer, thereby improving the durability of the adhesive layer. On the other hand, if it is 5000g/m ² ·day or less, the adhesive layer will be less likely to absorb moisture and expand, and the bonding durability will be excellent against dimensional changes, etc.

If the water vapor transmittance of the adhesive layer is higher than the water vapor transmittance of the optical film, it is preferable from the viewpoint of the durability of the bonding layer formed when the optical film and the polarizing sub-layer are bonded. By making the water vapor transmittance of the adhesive layer higher than that of the optical film, moisture and solvents can easily diffuse into the optical film and then into the adhesive layer.

Moreover, the manufacturing method of the polarizing plate roll of the present invention is a manufacturing method of the polarizing plate roll manufactured by the following steps: on the aforementioned optical film surface side of a laminated film composed of at least an optical film, an adhesive layer, and a release film , the laminating step of laminating polarizers to produce a polarizing plate, and the winding step of winding the aforementioned polarizing plate; characterized in that: the film thickness of the aforementioned adhesive layer is 1 μm to less than 10 μm, and the film thickness of the optical film is 1 μm ~Less than 10μm. This feature is a technical feature common to or corresponding to the following embodiments.

As an embodiment of the present invention, from the viewpoint of exhibiting the effects of the present invention, it is preferable from the viewpoint of productivity and durability to wind up the release film without peeling off the release film in an intermediate step. That is, by winding it up with the release film, the adhesive layer is prevented from adhering to the manufacturing equipment, the support, etc. Moreover, it can be easily formed into an appropriate shape.

Furthermore, from the same viewpoint, the polarizing plate roll is preferably composed of at least the release film, the adhesive layer, the optical film and the polarizer.

The polarizing plate of the present invention can be applied to a display device.

Hereinafter, the present invention, its constituent elements, and forms and aspects for implementing the present invention will be described in detail. In this case, "~" is used to include the numerical values described before and after it as the lower limit and upper limit. However, if there is "over" or "under" before the value, the value is not included as the lower limit and upper limit. For example, "1 to less than 10 μm" specifically refers to "more than 1 μm and less than 10 μm".

≪1 Overview of the laminated film of the present invention≫ The laminated film of the present invention is a laminated film composed of at least an optical film, an adhesive layer and a release film, and is characterized in that the film thickness (also referred to as "thickness") of the aforementioned optical film is 1 to less than 10 μm, and the aforementioned The film thickness of the adhesive layer is 1~less than 10μm.

FIG. 1A is a cross-sectional view showing the basic structure of the layer structure of the laminated film 50 of the present invention. The laminated film 50 of the present invention is composed of an optical film 1, an adhesive layer 2 and a release film 3 as shown in FIG. 1A.

Furthermore, as shown in FIG. 1B , the support 4 for forming the optical film 1 can be disposed on the surface of the optical film 1 opposite to the surface in contact with the adhesive layer 2 . The support 4 also functions as a protective film for the optical film of the present invention, that is, it provides sufficient stiffness to the laminated film 50 during step operations, and becomes a support that is easy to handle.

Hereinafter, the components of the present invention will be described in detail. However, in the following description, the present invention is not limited thereto.

[1.1] Optical film The optical film of the present invention is characterized by a thickness in the range of 1 to less than 10 μm. Within the above range, the function as a support in the polarizing plate is achieved and sufficient folding resistance is imparted. The thickness is preferably in the range of 2~8 μm, more preferably in the range of 3~7 μm.

When the thickness is less than 1 μm, the stiffness of the optical film becomes weak, and sufficient impact resistance cannot be obtained in the laminate when it is bonded to a glass plate. In addition, if it is 10 μm or more, the strength against bending decreases and optical unevenness occurs. In addition, in the polarizing plate including the laminated film of the present invention, since creases, folds, and whitening are likely to occur during bending, and optical defects are likely to occur, the polarizing plate must be within the above range.

Moreover, when the optical film contains an additive, it is preferable to contain an additive with a molecular weight of 1000 or less in the range of 0.0001 to 0.01 mass %.

[1.1.1] Resins constituting optical films The resin used in the optical film of the present invention is not particularly limited, and examples thereof include cellulose ester resin, cycloolefin resin, fumaric acid diester resin, polypropylene resin, (meth)acrylic resin, polypropylene resin, etc. Ester resin, polyarylate resin, polyimide resin, styrene resin or composite resin thereof. In addition, those containing a linear polymer material having a carbonyl group in the side chain, or a polymer material containing a cyclic structure in the main chain, are more advantageous from the viewpoint of suppressing physical properties such as folding resistance and improving optical properties. should. Therefore, it is preferable to use a cyclic olefin resin, a fumaric acid diester resin, a (meth)acrylic resin, a styrene-(meth)acrylate copolymer, or the like.

＜Cycloolefin-based resin＞ The cycloolefin-based resin used for the optical film is preferably a polymer of a cycloolefin monomer or a copolymer of a cycloolefin monomer and other copolymerizable monomers.

As the cyclic olefin monomer, a cyclic olefin monomer having a norbornene skeleton is preferred, and a cyclic olefin monomer having a structure represented by the following general formula (A-1) or (A-2) is more preferred.

In the general formula (A-1), R ¹ to R ⁴ each independently represent a hydrogen atom, a hydrocarbon group with 1 to 30 carbon atoms, or a polar group; p is an integer from 0 to 2. However, all of R ¹ to R ⁴ do not represent hydrogen atoms at the same time, R ¹ to R ² do not represent hydrogen atoms at the same time, and R ³ and R ⁴ do not represent hydrogen atoms at the same time.

In the general formula (A-1), as the hydrocarbon group having 1 to 30 carbon atoms represented by R ¹ to R ⁴ , for example, a hydrocarbon group having 1 to 10 carbon atoms is preferred, and a hydrocarbon group having 1 to 5 carbon atoms is more preferred. of hydrocarbon groups. The hydrocarbon group having 1 to 30 carbon atoms may further have a connecting group containing a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom or a silicon atom. Examples of such a linking group include divalent polar groups such as a carbonyl group, an imine group, an ether bond, a silyl ether bond, and a thioether bond. Examples of the hydrocarbon group having 1 to 30 carbon atoms include methyl, ethyl, propyl, butyl, and the like.

In the general formula (A-1), examples of the polar group represented by R ¹ to R ⁴ include a carboxyl group, a hydroxyl group, an alkoxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an amine group, and an amide group. and cyano. Among them, a carboxyl group, a hydroxyl group, an alkoxycarbonyl group and an aryloxycarbonyl group are preferred, and from the viewpoint of ensuring solubility during film formation from a solution, an alkoxycarbonyl group and an aryloxycarbonyl group are preferred.

From the viewpoint of improving the heat resistance of the optical film, p in the general formula (A-1) is preferably 1 or 2. This is because if p is 1 or 2, the volume of the resulting polymer system becomes larger and the glass transition temperature is likely to rise. In addition, it has the advantage of being able to respond somewhat to humidity and easily controlling the curl balance of the laminate.

In the general formula (A-2), R ⁵ represents a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, or an alkylsilyl group having an alkyl group having 1 to 5 carbon atoms; R ⁶ represents a carboxyl group, a hydroxyl group, an alkoxycarbonyl group, Aryloxycarbonyl group, amine group, amide group, cyano group or halogen atom (fluorine atom, chlorine atom, bromine atom or iodine atom); p represents an integer from 0 to 2.

R ⁵ in the general formula (A-2) preferably represents a hydrocarbon group having 1 to 5 carbon atoms, and more preferably represents a hydrocarbon group having 1 to 3 carbon atoms.

R ⁶ in the general formula (A-2) preferably represents a carboxyl group, a hydroxyl group, an alkoxycarbonyl group and an aryloxycarbonyl group, and from the viewpoint of ensuring solubility during film formation from a solution, an alkoxycarbonyl group is more preferable. and aryloxycarbonyl.

From the viewpoint of improving the heat resistance of the optical film, p in the general formula (A-2) preferably represents 1 or 2. This is because if p represents 1 or 2, the volume of the polymer obtained becomes larger and the glass transition temperature is likely to rise.

A cyclic olefin monomer having a structure represented by general formula (A-2) is preferable from the viewpoint of improving solubility in an organic solvent. Organic compounds generally reduce their crystallinity and increase their solubility in organic solvents by disrupting their symmetry. R ⁵ and R ⁶ in the general formula (A-2) are only substituted on one side of the ring to form a carbon atom for the symmetry axis of the molecule, so the symmetry of the molecule is low, that is, it has the general formula (A-2) The cyclic olefin monosystem of the structure shown has high solubility and is suitable for manufacturing optical films by solution casting.

In the polymer of the cycloolefin monomer, the content ratio of the cycloolefin monomer having the structure represented by the general formula (A-2) is relative to the total of all the cycloolefin monomers constituting the cycloolefin-based resin. For example, it can be It is 70 mol% or more, preferably 80 mol% or more, more preferably 100 mol%. If more than a certain amount of the cycloolefin monomer having the structure represented by the general formula (A-2) is contained, the alignment of the resin increases, so the phase difference (retardation) value tends to increase.

Hereinafter, specific examples of cycloolefin monomers having a structure represented by general formula (A-1) are shown in Exemplary Compounds 1 to 14, and cyclic olefin monomers having a structure represented by General Formula (A-2) are shown in Exemplary Compounds 15 to 34. Specific examples of structural cycloolefin monomers.

Examples of copolymerizable monomers copolymerizable with cycloolefin monomers include copolymerizable monomers capable of ring-opening copolymerization with cycloolefin monomers and copolymerizable monomers capable of addition copolymerization with cycloolefin monomers. Polymerizable monomers, etc.

Examples of copolymerizable monomers capable of ring-opening copolymerization include cyclic olefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, and dicyclopentadiene.

Examples of copolymerizable monomers capable of addition copolymerization include compounds containing unsaturated double bonds, vinyl cyclic hydrocarbon monomers, (meth)acrylic acid esters, and the like. The compound containing an unsaturated double bond is, for example, an olefin compound having 2 to 12 carbon atoms (preferably 2 to 8). Examples thereof include ethylene, propylene, butylene, and the like. Examples of vinyl cyclic hydrocarbon monomers include vinyl cyclopentene monomers such as 4-vinylcyclopentene and 2-methyl-4-isopropenylcyclopentene. Examples of (meth)acrylate include methyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, and the like having 1 to 20 carbon atoms. Alkyl (meth)acrylates.

The content ratio of the cyclic olefin monomer in the copolymer of the cyclic olefin monomer and the copolymerizable monomer is relative to the total of all the monomers constituting the copolymer, and may be in the range of 20 to 80 mol%, for example. Preferably, it is within the range of 30~70 mol%.

The cycloolefin resin is a cycloolefin monomer having a norbornene skeleton, preferably a cycloolefin monomer having a structure represented by the general formula (A-1) or (A-2), as described above, polymerized or co-formed Examples of polymers obtained by polymerization include the following.

(1) Ring-opening polymer of cycloolefin monomer (2) Ring-opening copolymers of cyclic olefin monomers and polymerizable monomers capable of ring-opening copolymerization (3) Hydrogenated product of the ring-opened (co)polymer of the above (1) or (2) (4) A (co)polymer in which the ring-opened (co)polymer of the above (1) or (2) is cyclized by Friedel-Crafts reaction and then hydrogenated (5) Saturated copolymers of cyclic olefin monomers and compounds containing unsaturated double bonds (6) Addition copolymers of cycloolefin monomers and vinyl cyclic hydrocarbon monomers and their hydrogenated products (7) Alternating copolymer of cyclic olefin monomer and (meth)acrylate

The polymers of the above (1) to (7) can be obtained by well-known methods, such as the methods described in Japanese Patent Application Laid-Open No. 2008-107534 or Japanese Patent Application Laid-Open No. 227606. The catalyst or solvent used for the ring-opening copolymerization in the above (2) may be those described in paragraphs 0019 to 0024 of Japanese Patent Application Laid-Open No. 2008-107534, for example. The catalyst used for the hydrogenation in the above-mentioned (3) and (6) may be those described in paragraphs 0025 to 0028 of Japanese Patent Application Laid-Open No. 2008-107534, for example.

As the acidic compound used in the Friedel-Quaft reaction in (4), for example, those described in paragraph 0029 of Japanese Patent Application Laid-Open No. 2008-107534 can be used. Catalysts used for the addition polymerization in the above (5) to (7) can be used, for example, those described in paragraphs 0058 to 0063 of Japanese Patent Application Laid-Open No. 2005-227606. The alternating copolymerization reaction of the above (7) can be carried out by the method described in paragraphs 0071 and 0072 of Japanese Patent Application Laid-Open No. 2005-227606, for example.

Among them, the polymers of the above-mentioned (1) to (3) and (5) are preferred, and the polymers of the above-mentioned (3) and (5) are more preferred. That is, the cycloolefin-based resin preferably contains a structural unit represented by the following general formula (B-1) and At least one of the structural units represented by the following general formula (B-2), more preferably only the structural unit represented by the general formula (B-2), or the structure represented by the general formula (B-1) Both the unit and the structural unit represented by general formula (B-2).

The structural unit represented by the general formula (B-1) is a structural unit derived from the cycloolefin monomer represented by the aforementioned general formula (A-1), and the structural unit represented by the general formula (B-2) is derived from the aforementioned Structural unit of the cycloolefin monomer represented by the general formula (A-2).

In the general formula (B-1), X represents -CH=CH- or -CH ₂ CH ₂ -; R ¹ to R ⁴ and p are each synonymous with R ¹ to R ⁴ and p of the general formula (A-1).

In the general formula (B-2), X represents -CH=CH- or -CH ₂ CH ₂ -; R ⁵ to R ⁶ and p are each synonymous with R ⁵ to R ⁶ and p of the general formula (A-2).

Commercially available cycloolefin-based resins used in the present invention can be used, and examples thereof include Arton (registered trademark) G (for example, G7810, etc.) manufactured by JSR Co., Ltd., Arton F, and Arton R (for example, R4500, R4900 and R5000, etc.) and Atong RX (for example, RX4500, etc.).

When measured at 30°C, the intrinsic viscosity [eta]inh of the cycloolefin resin is preferably in the range of 0.2~ ^5cm3 /g, more preferably in the range of 0.3~ ^3cm3 /g, and particularly preferably in the range of 0.4~ Within the range of 1.5cm ³ /g.

The number average molecular weight (Mn) of the cycloolefin resin is preferably in the range of 8,000 to 100,000, more preferably in the range of 10,000 to 80,000, and particularly preferably in the range of 12,000 to 50,000. The weight average molecular weight (Mw) of the cycloolefin resin is preferably in the range of 20,000 to 300,000, more preferably in the range of 30,000 to 250,000, and particularly preferably in the range of 40,000 to 200,000. The number average molecular weight or weight average molecular weight of the cycloolefin-based resin can be measured in terms of polystyrene by gel permeation chromatography (GPC).

＜Gel permeation chromatography＞ Solvent: methylene chloride Pipe string: Shodex (registered trademark) K806, K805, K803G (manufactured by Showa Denko Co., Ltd., used by connecting 3 pieces) Column temperature: 25℃ Sample concentration: 0.1 mass% Detector: RI Model 504 (manufactured by GL Scientific Corporation) Pump: L6000 (made by Hitachi Manufacturing Co., Ltd.) Flow: 1.0mL/min Calibration curve: Use the calibration curve of 13 samples in the range of standard polystyrene STK standard polystyrene (Tosoh Co., Ltd.) Mw=500~2800000. The 13 samples are preferably used at approximately equal intervals.

When the intrinsic viscosity [eta]inh, the number average molecular weight, and the weight average molecular weight are within the above ranges, the heat resistance, water resistance, chemical resistance, mechanical properties, and molding processability of the cycloolefin-based resin as an optical film become good.

The glass transition temperature (Tg) of the cycloolefin-based resin is usually 110°C or higher, preferably in the range of 110 to 350°C, more preferably in the range of 120 to 250°C, especially preferably in the range of 120 to 220°C. If Tg is 110°C or higher, deformation under high temperature conditions can be easily suppressed. On the other hand, if Tg is 350° C. or less, molding processing becomes easier, and deterioration of the resin due to heat during molding processing is also easily suppressed.

The content of the cycloolefin-based resin is preferably 70 mass% or more, more preferably 80 mass% or more, based on the optical film.

＜Fumaric acid diester resin＞ The fumaric acid diester resin used in the optical film is a fumaric acid diester resin containing a diisopropyl fumarate residue unit and a fumaric acid diester residue unit having an alkyl group with 1 or 2 carbon atoms. .

Here, the alkyl groups having 1 or 2 carbon atoms in the fumaric acid diester residue unit having an alkyl group with 1 or 2 carbon atoms are each independent, and examples thereof include methyl, ethyl, and the like. Furthermore, these may be substituted by a halogen group, an ether group, an ester group or an amino group such as fluorine or chlorine. Examples of the fumarate diester residue unit having an alkyl group having 1 or 2 carbon atoms include a dimethyl fumarate residue unit and a diethyl fumarate residue unit. Moreover, these may contain 1 type or 2 or more types.

Specific examples of the fumaric acid diester resin include diisopropyl fumarate/dimethyl fumarate copolymer resin and diisopropyl fumarate/diethyl fumarate copolymer resin. wait.

The aforementioned fumaric acid diester resin may also contain other monomer residue units as long as it does not exceed the scope of the present invention. Examples of other monomer residue units include styrene residue units, α - Styrenic residue units such as methylstyrene residue units; (meth)acrylic acid residue units; (meth)acrylic acid methyl ester residue units, (meth)ethyl acrylate residue units, (meth)acrylic acid residue units, (Meth)acrylate residue units such as butyl acrylate residue units; vinyl ester residue units such as vinyl acetate residue units and vinyl propionate residue units; acrylonitrile residue units; Acrylonitrile residue unit; vinyl ether residue unit such as methyl vinyl ether residue unit, ethyl vinyl ether residue unit, butyl vinyl ether residue unit, etc.; N-methyl maleyl N-substituted maleimine residue units such as imine residue units, N-cyclohexylmaleimide residue units, N-phenylmaleimine residue units, etc.; ethylene residue units , propylene residue unit and other olefin residue units; di-n-butyl fumarate residue unit, fumarate bis (2-ethylhexyl) ester residue unit and other aforementioned fumaric acid diester residue units Fumaric acid diester residue units other than fumaric acid diester residue units; and one or more types selected from cinnamic acid and cinnamic acid ester residue units.

The blending ratio of the fumaric acid diester resin used in the present invention is preferably in the range of 50 to 99 mol% of the diisopropyl fumarate residue unit and the richness of the alkyl group having 1 or 2 carbon atoms. The maleic acid diester residue unit ranges from 1 to 50 mol%. From the viewpoint of improving the retardation characteristics or strength when forming a retardation film, the diisopropyl fumarate residue unit in the range of 60 to 95 mol% and an alkyl group having 1 or 2 carbon atoms are particularly preferred. A fumaric acid diester resin with a fumaric acid diester residue unit in the range of 5 to 40 mol%.

The fumaric acid diester resin used in the present invention preferably has a number average molecular weight in the range of 50,000 to 250,000 in terms of standard polystyrene based on the elution curve measured by the aforementioned gel permeation chromatography.

＜Polyarylate resin＞ Polyarylate resins have excellent toughness when used in optical films. This polyarylate resin contains at least a structural unit derived from an aromatic diol and a structural unit derived from an aromatic dicarboxylic acid.

Commercially available polyarylate resins used in the present invention can be used. For example, PAR resin "U-100" manufactured by UNITIKA Co., Ltd. has a weight average molecular weight of 100,000.

＜Polyimide resin＞ The polyimide resin can be a polymerization reaction product of tetracarboxylic dianhydride and diamine.

The tetracarboxylic dianhydride may be any one of aromatic tetracarboxylic dianhydride, aliphatic tetracarboxylic dianhydride, and alicyclic tetracarboxylic dianhydride, but aromatic tetracarboxylic dianhydride is preferred. The diamine may be any of aromatic diamine, aliphatic diamine, and alicyclic diamine, but aromatic diamine is preferred.

The weight average molecular weight Mw of the polyimide resin is not particularly limited, but from the perspective of improving the toughness of the optical film and making it less likely to break due to transportation tension, it is preferably in the range of 100,000 to 300,000, and more preferably Within the range of 130,000 to 250,000. The method for measuring the weight average molecular weight Mw of the polyimide-based resin is the same as described above.

The content of the polyimide-based resin relative to the optical film is preferably 60 mass% or more, more preferably 70 mass% or more.

＜(Meth)acrylic resin＞ The (meth)acrylic resin used for the optical film preferably contains at least a structural unit (U1) derived from methyl methacrylate and a structural unit (U2) derived from phenylmaleimide. The (meth)acrylic resin containing the structural unit (U2) derived from phenylmaleimide has the advantage of reducing the photoelastic coefficient of the optical film and is less likely to cause unevenness even if it expands due to moisture absorption.

The (meth)acrylic resin may further contain other structural units other than the above. Examples of such other structural units include (meth)acrylic acid alkyl esters such as adamantyl acrylate; and (meth)acrylic acid cycloalkyl esters such as 2-ethylhexyl acrylate. Among them, from the viewpoint of reducing deterioration in brittleness due to the inclusion of the structural unit (U2) derived from phenylmaleimide, it is preferred to further include the structural unit (U3) derived from an alkyl acrylate.

That is, the (meth)acrylic resin more preferably contains a structural unit (U1) derived from methyl methacrylate, a structural unit (U2) derived from phenylmaleimide, and a structural unit derived from an alkyl acrylate. Structural unit (U3).

The content of the structural unit (U1) derived from methyl methacrylate is preferably 50 to 95 mass %, more preferably 70 to 90 mass %, based on all the structural units constituting the (meth)acrylic resin.

The structural unit (U2) derived from phenylmaleimide can improve the mechanical strength of the optical film because it has a relatively rigid structure. In addition, the structural unit (U2) derived from phenylmaleimide is a structure with a relatively large volume. Since it has micro voids in the resin matrix that allow the rubber particles to move, the rubber particles can be preferentially present in the resin matrix. The surface layer of the optical film.

The content of the structural unit (U2) derived from phenylmaleimide is preferably in the range of 1 to 25 mass % with respect to all the structural units constituting the (meth)acrylic resin. When the content of the structural unit (U2) derived from phenylmaleimide is 1 mass % or more, the optical film has excellent storage stability in a high-humidity environment. If it is 25% by mass or less, the brittleness of the optical film will not be excessively damaged. From the above point of view, the content of the structural unit (U2) derived from phenylmaleimide is more preferably in the range of 7 to 15 mass %.

The structural unit (U3) derived from an alkyl acrylate can impart moderate flexibility to the resin, and therefore, for example, the brittleness caused by the structural unit (U2) derived from phenylmaleimide can be improved.

The alkyl acrylate is preferably an alkyl acrylate in which the number of carbon atoms in the alkyl part is in the range of 1 to 7, preferably in the range of 1 to 5. Examples of the alkyl acrylate include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate, hexyl acrylate, and 2-ethylhexyl acrylate.

The content of the structural unit (U3) derived from the alkyl acrylate is preferably in the range of 1 to 25 mass % with respect to all the structural units constituting the (meth)acrylic resin. When the content of the structural unit (U3) derived from alkyl acrylate is 1 mass % or more, moderate flexibility can be imparted to the (meth)acrylic resin, so that the brittleness of the optical film is suppressed and the film is less likely to break. When the content of the structural unit (U3) derived from alkyl acrylate is 25% by mass or less, the glass transition temperature (Tg) of the optical film is not too low, and the optical film has excellent storage stability in a high-humidity environment. From the above point of view, the content of the structural unit (U3) derived from alkyl acrylate is more preferably in the range of 5 to 15 mass %.

Ratio of the structural unit (U2) derived from phenylmaleimide relative to the total amount of the structural unit (U2) derived from phenylmaleimide and the structural unit (U3) derived from alkyl acrylate Preferably, it is in the range of 20 to 70 mass%. If the ratio is 20 mass% or more, the elastic modulus of the optical film can be easily increased, and if the ratio is 70 mass% or less, the brittleness of the optical film can be suppressed.

The glass transition temperature (Tg) of the (meth)acrylic resin is preferably 100°C or higher, more preferably within the range of 120 to 150°C. When the Tg of the (meth)acrylic resin is within the above range, the heat resistance of the optical film can be easily improved. In order to adjust the Tg of the (meth)acrylic resin, it is preferable to adjust the content of the structural unit (U2) derived from phenylmaleimide or the structural unit (U3) derived from alkyl acrylate, for example.

The weight average molecular weight (Mw) of the (meth)acrylic resin is not particularly limited and can be adjusted according to the purpose. The weight average molecular weight of the (meth)acrylic resin is used, for example, to promote the entanglement of resin molecules to improve the toughness of the optical film and make it less likely to break, or to moderately increase the humidity expansion coefficient (also known as the "CHE ratio" ), from the viewpoint of the amount of curling that can be easily adjusted to a better level for adhesion, it is preferably 100,000 or more, and more preferably 1,00,000 or more. If the weight average molecular weight of the (meth)acrylic resin is 1 million or more, the toughness of the resulting optical film can be improved. This can prevent the optical film from breaking due to transportation tension during transportation of the optical film, thereby improving transportation stability. From the same viewpoint, the weight average molecular weight of the (meth)acrylic resin is more preferably in the range of 1.5 million to 3 million. The method for measuring the weight average molecular weight is as described above.

＜Styrene-(meth)acrylate copolymer＞ Styrene-(meth)acrylate copolymer (hereinafter also referred to as styrene-acrylic resin) has excellent transparency when used for optical films. Furthermore, since the hygroscopic expansion coefficient can also be adjusted by the copolymerization ratio of the styrene part, curling of the laminate can be suppressed by changing these ratios.

The styrene-acrylic resin is formed by addition polymerization of at least a styrene monomer and a (meth)acrylic acid ester monomer. In addition to styrene represented by the structural formula CH ₂ =CH-C ₆ H ₅ , the styrene monosystem also includes styrene derivatives with well-known side chains or functional groups in the styrene structure.

In addition, the (meth)acrylate monosystem except the acrylate or methyl group represented by CH(R ₁ )= CHCOOR ₂ (R ₁ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group with a carbon number of 1 to 24) In addition to acrylates, acrylate derivatives or methacrylate derivatives having well-known side chains or functional groups in the structure of these esters are also included.

Examples of styrene monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p -Ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylstyrene Ethylene and p-n-dodecylstyrene.

Examples of (meth)acrylate monomers include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, tert-butyl acrylate, isobutyl acrylate, n-octyl acrylate, and acrylic acid. Acrylate monomers such as 2-ethylhexyl (2EHA), stearyl acrylate, lauryl acrylate and phenyl acrylate; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, methyl methacrylate Isopropyl acrylate, isobutyl methacrylate, tert-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, Methacrylates such as phenyl methacrylate, diethyl aminoethyl methacrylate, and dimethylaminoethyl methacrylate.

In addition, in this specification, the so-called "(meth)acrylate monomer" is a general term for "acrylate monomer" and "methacrylate monomer", and means one or both of them. For example, "methyl (meth)acrylate" means one or both of "methyl acrylate" and "methyl methacrylate".

The number of the above-mentioned (meth)acrylic acid ester monomers may be one type or more than one type. For example, any of the following may be used: a copolymer is formed using a styrene monomer and two or more types of acrylate monomers, or a copolymer is formed using a styrene monomer and two or more types of methacrylate monomers, And a copolymer is formed by using styrene monomer, acrylate monomer and methacrylate monomer together.

The weight average molecular weight (Mw) of the above-mentioned styrene-acrylic resin is preferably in the range of 5,000 to 150,000, and more preferably in the range of 30,000 to 120,000, from the viewpoint of easy control of plasticity.

The styrene-acrylic resin used in the present invention can be commercially available, and for example, MS resin "TX320XL" manufactured by DENKA Co., Ltd. can be used.

[1.1.2] Rubber particles The optical film of the present invention, especially when a (meth)acrylic resin or a styrene-(meth)acrylate copolymer is used, contains rubber particles in a range of 10 to 90% by mass relative to the optical film. Toughness (flexibility) is preferred from the viewpoint of improving impact resistance. In addition, it is also preferable from the viewpoint of improving the magnitude of the effect and preventing the occurrence of haze. More preferably, it is in the range of 40 to 85% by mass.

The rubber particles of the present invention are particles containing a rubber-like polymer. The rubbery polymer is a soft cross-linked polymer with a glass transition temperature of 20°C or lower. Examples of such cross-linked polymers include butadiene-based cross-linked polymers, (meth)acrylic acid-based cross-linked polymers, and organosiloxane-based cross-linked polymers. By appropriately adjusting the ratio of these resins, the difference in refractive index with the matrix polymer in which the rubber particles are dispersed can be eliminated, and the occurrence of haze can be suppressed. Among them, from the viewpoint of not easily damaging the transparency of the optical film, a (meth)acrylic cross-linked polymer is preferable, and an acrylic cross-linked polymer (acrylic rubber-like polymer) is more preferable.

That is, the rubber particles are preferably particles containing the acrylic rubber-like polymer (a).

About acrylic rubber-like polymer (a): The acrylic rubber-like polymer (a) is a cross-linked polymer containing a structural unit derived from an acrylate as a main component. What is included as a main component means that the content of the structural unit derived from acrylic acid ester falls within the range described below. The acrylic rubber-like polymer (a) preferably contains a structural unit derived from an acrylic ester, a structural unit derived from another monomer copolymerizable with the acrylic acid ester, and a structural unit derived from having two or more radically polymerizable groups in one molecule. A cross-linked polymer of structural units of multifunctional monomers (non-conjugated reactive double bonds).

Preferred acrylates are methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, 2-butyl acrylate, isobutyl acrylate, benzyl acrylate, cyclohexyl acrylate, and 2-ethylhexyl acrylate. , n-octyl acrylate, etc. The alkyl group has 1 to 12 acrylic acid alkyl esters. The acrylate may be one type or two or more types.

The content of the structural units derived from acrylate is preferably in the range of 40 to 80 mass %, more preferably in the range of 50 to 80 mass %, relative to all the structural units constituting the acrylic rubber-like polymer (a1). When the acrylate content is within the above range, sufficient toughness can be easily imparted to the optical film.

Other copolymerizable monomers are those other than polyfunctional monomers among the monomers copolymerizable with acrylate. That is, the copolymerizable monomer does not have two or more radically polymerizable groups. Examples of copolymerizable monomers include methacrylates such as methyl methacrylate; styrenes such as styrene and methylstyrene; (meth)acrylonitriles; (meth)propylene Amides; (meth)acrylic acid. Among them, other copolymerizable monomers preferably include styrenes. The other copolymerizable monomers may be one type or two or more types.

The content of structural units derived from other copolymerizable monomers is preferably in the range of 5 to 55 mass %, more preferably 10 to 45 mass %, relative to all structural units constituting the acrylic rubber-like polymer (a). within the range of %.

Examples of the polyfunctional monomer include allyl (meth)acrylate, triallyl cyanurate, triallyl isocyanate, diallyl phthalate, apple Diallyl acid, divinyl adipate, divinylbenzene, ethylene glycol di(meth)acrylate, diethylene glycol (meth)acrylate, triethylene glycol di(meth)acrylic acid Ester, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, dipropylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate.

The content of the structural units derived from the polyfunctional monomer is preferably in the range of 0.05 to 10 mass %, more preferably 0.1 to 5 mass %, relative to all the structural units constituting the acrylic rubber-like polymer (a). within the range. If the content of the polyfunctional monomer is 0.05% by mass or more, the degree of cross-linking of the obtained acrylic rubber-like polymer (a) is easily increased, so the hardness and rigidity of the obtained optical film are not excessively impaired. If it is 10% by mass % or less, the toughness of the optical film will not be easily damaged.

The monomer composition constituting the acrylic rubber-like polymer (a) can be measured, for example, by the peak area ratio detected by thermal decomposition GC-MS.

The glass transition temperature (Tg) of the rubber-like polymer is preferably 0°C or lower, more preferably -10°C or lower. If the glass transition temperature (Tg) of the rubber-like polymer is 0° C. or lower, appropriate toughness can be imparted to the film. The glass transition temperature (Tg) of the rubbery polymer is measured in the same manner as described above.

The glass transition temperature (Tg) of the rubbery polymer can be adjusted by the composition of the rubbery polymer. For example, in order to lower the glass transition temperature (Tg) of the acrylic rubber-like polymer (a), it is preferable to increase the number of acrylic acid esters having 4 or more carbon atoms in the alkyl group of the acrylic rubber-like polymer (a). The mass ratio of other polymerized monomers (for example, 3 or more, preferably in the range of 4 to 10).

The particles containing the acrylic rubber-like polymer (a) may be particles made of the acrylic rubber-like polymer (a), or may be a hard cross-linked polymer (c) having a glass transition temperature of 20° C. or higher ) and particles of a soft layer made of acrylic rubber-like polymer (a) arranged around it (these are also called "elastomers"); it may also be made of acrylic rubber Particles made of an acrylic graft copolymer obtained by polymerizing a mixture of monomers such as methacrylate in at least one stage in the presence of polymer (a). The particles made of the acrylic graft copolymer may be core-shell type particles having a core containing the acrylic rubber-like polymer (a) and a shell covering the core.

Regarding core-shell rubber particles containing acrylic rubber-like polymer: (core) The core contains an acrylic rubber-like polymer (a) and may further contain a hard cross-linked polymer (c) if necessary. That is, the core may have a soft layer made of an acrylic rubber-like polymer and a hard layer made of a hard cross-linked polymer (c) arranged inside.

The cross-linked polymer (c) may be a cross-linked polymer containing methacrylate as its main component. That is, the cross-linked polymer (c) preferably contains one of a structural unit derived from an alkyl methacrylate, a structural unit derived from other monomers copolymerizable with it, and a structural unit derived from a polyfunctional monomer. Cross-linked polymers.

The alkyl methacrylate can be the aforementioned alkyl methacrylate; other copolymerizable monomers can be the aforementioned styrenes or acrylic esters; the polyfunctional monomers can be exemplified by those listed as the aforementioned polyfunctional monomers. Same thing.

The content of structural units derived from alkyl methacrylate may be in the range of 40 to 100% by mass relative to all structural units constituting the cross-linked polymer (c). Relative to all structural units constituting other cross-linked polymer (c), the content of structural units derived from other copolymerizable monomers may be in the range of 0 to 60 mass %. Relative to all structural units constituting other cross-linked polymers, the content of structural units derived from multifunctional monomers may be in the range of 0.01 to 10 mass %.

(shell part) The shell portion contains methacrylic polymer (b) (other polymer) containing a structural unit derived from methacrylate as a main component graft-bonded to acrylic rubber-like polymer (a). What is contained as a main component means that the content of the structural unit derived from methacrylate falls within the range described below.

The methacrylate constituting the methacrylic polymer (b) is preferably an alkyl methacrylate, such as methyl methacrylate, whose alkyl group has a carbon number in the range of 1 to 12. The methacrylate may be one type or two or more types.

The content of methacrylic acid ester is preferably 50% by mass or more based on all the structural units constituting the methacrylic polymer (b). When the content of methacrylate is 50% by mass or more, compatibility with a methacrylic resin containing a structural unit derived from methyl methacrylate as a main component can be easily obtained. From the above viewpoint, the content of methacrylate is more preferably 70 mass % or more based on all the structural units constituting the methacrylic polymer (b).

The methacrylic polymer (b) may further contain structural units derived from other monomers copolymerizable with the methacrylic acid ester. Examples of other monomers that can be copolymerized include acrylates such as methyl acrylate, ethyl acrylate, n-butyl acrylate, etc.; benzyl (meth)acrylate, dicyclopentyl (meth)acrylate, (meth)acrylate, etc. (Meth)acrylic monomers (ring-containing (meth)acrylic monomers) having alicyclic, heterocyclic or aromatic rings such as phenoxyethyl acrylate.

The content of the structural units derived from the copolymerizable monomer is preferably 50 mass % or less, more preferably 30 mass % or less relative to all the structural units constituting the methacrylic polymer (b).

In this embodiment, since the optical film is not stretched, the shape of the rubber particles can be close to a true spherical shape. That is, when observing the cross section or surface of the optical film, the aspect ratio of the rubber particles can be about 1 to 2.

The average particle size of the rubber particles of the present invention is preferably in the range of 100 to 400 nm. If the average particle diameter of the rubber particles is 100 nm or more, sufficient toughness or stress relaxation properties can be easily imparted to the optical film. If the average particle diameter is 400 nm or less, the transparency of the optical film is less likely to be impaired. Based on the same point of view, the average particle size of rubber particles is preferably in the range of 150 to 300 nm.

The average particle size of rubber particles can be calculated by the following method.

The average particle diameter of rubber particles can be measured as the average value of the equivalent circular diameter of 100 particles obtained by SEM photography or TEM photography of the surface or slices of the laminated film. The equivalent circle diameter can be obtained by converting the projected area of the photographed particle into the diameter of a circle with the same area. At this time, the rubber particles observed by SEM observation and/or TEM observation at a magnification of 5000 times are used for calculation of the average particle diameter.

[1.1.3]Additives The optical film of the present invention may further contain additives if necessary. It is preferable that the additive with a molecular weight of 1000 or less is contained in the range of 0.0001 to 1 mass % relative to the optical film, and more preferably in the range of 0.001 to 0.1 mass %. Examples of other components include antioxidants, matting agents (fine particles), plasticizers, ultraviolet absorbers, and antistatic agents.

＜Antioxidants＞ From the viewpoint of suppressing the diffusion of precipitates, the optical film of the present invention preferably contains an antioxidant with a molecular weight of 1000 or less in the range of 0.0001 to 0.01 mass % relative to the optical film, which can improve the performance of the optical film over time. Passed preservation.

As antioxidants, well-known ones can be used. In particular, lactone-based, sulfur-based, phenolic-based, double-bond-based, hindered amine-based, and phosphorus-based compounds can be suitably used.

Commercially available products can be used as the above-mentioned lactone compound, and examples thereof include "Irgafos XP40 and Irgafos XP60 (trade name)" manufactured by BASF Japan Co., Ltd.

Commercially available products can be used as the sulfur-based compound, and examples thereof include "Sumilizer "(registered trademark) TPL-R" and "Sumilizer "(registered trademark) TP-D" manufactured by Sumitomo Chemical Co., Ltd.

As the above-mentioned phenolic compound, one having a structure of 2,6-dialkylphenol is preferred, and commercially available products can be used. For example, "Irganox (registered trademark) 1076" and "Irganox" manufactured by BASF Japan Co., Ltd. (Registered Trademark) 1010", "ADK STAB (Registered Trademark) AO-50" manufactured by ADEKA Co., Ltd., etc.

Commercially available products can be used as the double bond compound, and examples thereof include "Sumilizer (registered trademark) GM" and "Sumilizer (registered trademark) GS" manufactured by Sumitomo Chemical Co., Ltd. Generally speaking, it is added in the range of 0.05 to 20 mass % relative to the resin, and preferably in the range of 0.1 to 1 mass %.

Commercially available products can be used as the hindered amine compound, and examples thereof include "Tinuvin (registered trademark) 144" and "Tinuvin (registered trademark) 770" manufactured by BASF Japan Co., Ltd., and "ADK STAB (registered trademark) manufactured by ADEKA Co., Ltd. Registered trademark)LA-52".

Commercially available products can be used as the phosphorus-based compound, and examples thereof include "Sumilizer (registered trademark) GP" manufactured by Sumitomo Chemical Co., Ltd., "ADK STAB (registered trademark) PEP-24G" manufactured by ADEKA Co., Ltd., and "ADK STAB (registered trademark) PEP-36" and "ADK STAB (registered trademark) 3010", "IRGAFOS P-EPQ" manufactured by BASF Japan Co., Ltd., and "GSY-P101" manufactured by Sakai Chemical Industry Co., Ltd.

Furthermore, as the acid trapping agent, a compound having an epoxy group as described in US Pat. No. 4,137,201 may also be included.

These antioxidants are preferably included in the range of 0.0001 to 0.01 mass %, more preferably added in the range of 0.002 to 0.01 mass %, relative to the resin that is the main raw material of the optical film.

Only one type of these antioxidants may be used, or several different compounds may be used in combination. For example, it is preferable to use a lactone type, a phosphorus type, a phenol type, and a double bond type compound together.

＜Fine particles＞ The optical film of the present invention also preferably contains fine particles.

As the fine particles used in the present invention, examples of inorganic compounds include silica, titanium dioxide, alumina, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, and hydrated calcium silicate. Calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. In addition, fine particles of organic compounds can also be preferably used. Examples of the organic compound include polytetrafluoroethylene, cellulose acetate, polystyrene, polymethyl methacrylate, polypropyl methacrylate, polymethyl acrylate, polyethylene carbonate, and benzene acrylate. Vinyl resin, polysiloxy resin, polycarbonate resin, benzoguanamine resin, melamine resin, polyolefin powder, polyester resin, polyamide resin, polyimide resin, or Pulverized fractions of organic polymer compounds such as polyvinyl fluoride resin and starch, or polymer compounds synthesized by suspension polymerization.

If the microparticles contain silicon, it is more suitable when the turbidity becomes low. Silicon dioxide is particularly preferred, such as Aerosil (registered trademark) R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (The above products are commercially available under the trade names of Japan AEROSIL Co., Ltd. and can be used.

[1.1.4] Physical properties of optical films ＜Thickness＞ By adjusting the thickness of the optical film of the present invention to satisfy the following formula 1, the adhesion with the adhesive layer can be improved, and the adhesive layer can be formed by coating.

Formula 1: 5＜｜The average value of the thickness of three randomly selected points in the width direction (B) - average film thickness value (A) |/average film thickness value (A) × 100＜20 (%) Here, the average film thickness value (A) is the average value of film thickness values at 10 points arbitrarily extracted from the film.

The value expressed by the average value (B) of the thickness of three arbitrarily selected points in the width direction in Formula 1 - average film thickness value (A) | / average film thickness value (A) × 100 (%) exceeds 5%, since the surface has moderate unevenness, the effect of improving the adhesion with the upper layer can be obtained. By less than 20%, the unevenness of the surface is not too large and does not affect the coating properties and smoothness of the upper layer. In addition, it is more preferable from the viewpoint of durability of the adhesive layer that it is 8% or more and less than 17%.

The film thickness can be measured using a commercially available film thickness measuring device. For example, an example of the film thickness measuring system is "F20-UV" manufactured by FILMETRICS.

In addition, the thickness deviation ρ of the optical film is preferably adjusted to a range of 0.5±0.2 μm. In detail, the manufacturing method of the laminated film mentioned later is demonstrated.

<Water vapor transmittance> The water vapor transmittance of the optical film of the present invention is in the range of 500 to 3000 g/m ² ·day at a temperature of 40°C and a humidity of 90% RH. In a polarizing plate, the bonding layer formed when the optical film and the polarizing sub-layer are bonded together is preferable from the viewpoint of durability. By setting the moisture permeability of the optical film to 500g/ ^m2 ·day or more, the moisture and solvent contained in the adhesive layer are easily diffused to the optical film side, and the adhesive durability is improved. On the other hand, if it is 3000 g/m ² ·day or less, the optical film will be less likely to absorb moisture and swell, and will have excellent adhesion durability against dimensional changes and the like.

Furthermore, it is more preferably within the range of 750~2500g/ ^m2 ·day, and particularly preferably within the range of 1000~2000g/ ^m2 ·day. The optical film of the present invention is preferably moisture-permeable from the same viewpoint as above. The method for measuring the above-mentioned water vapor transmission rate will be described in detail in the column of Examples below.

＜Phase difference Ro and Rt＞ The optical film of the present invention has a polarizing sub-layer laminated on the surface and can function as an optical film such as a phase difference film.

From the viewpoint of using the optical film as a retardation film for an IPS mode, for example, the retardation Ro in the in-plane direction measured in an environment with a wavelength of 590 nm, 23°C, and 55% RH is preferably in the range of 0 to 10 nm. More preferably, it is within the range of 0~5nm. The phase difference Rt in the thickness direction of the optical film is preferably in the range of -40~40nm, more preferably in the range of -25~25nm.

Ro and Rt are each defined by the following formula.

(In the _{formula , n} The refractive index in the thickness direction of the film, d represents the thickness of the optical film (nm)). The in-plane slow axis system of the optical film can be confirmed with an automatic birefringence meter Axo Scan (Axo Scan Mueller Matrix Polarimeter: manufactured by AXOMETRICS).

Ro and Rt can be measured by the following method.

(1) Humidify the optical film in an environment of 23°C and 55%RH for 24 hours. The average refractive index of the film was measured with an Abbe refractometer, and the thickness d was measured using a commercially available micrometer.

(2) Using an automatic birefringence meter Axo Scan (Axo Scan Mueller Matrix Polarimeter: manufactured by AXOMETRICS), the retardation Ro and Rt of the film after humidity control at the measurement wavelength of 590 nm were measured in an environment of 23°C and 55% RH.

The retardation Ro and Rt of the optical film can be adjusted by, for example, the type of resin, stretching conditions, and drying conditions. For example, by increasing the drying temperature, Rt can be reduced.

[1.2]Adhesive layer The adhesive layer of the present invention is characterized by a thickness in the range of 1 to less than 10 μm. Within the above range, in a flexible display bonded to a glass plate, impact resistance is improved and unevenness during repeated folding is excellently suppressed.

When the thickness is less than 1 μm, the adhesive force to the glass plate decreases. In addition, when the thickness is 10 μm or more, a decrease in impact resistance and the occurrence of unevenness during repeated folding are likely to occur.

The aforementioned thickness is preferably in the range of 2~8 μm, more preferably in the range of 3~7 μm.

The adhesive layer of the present invention can be formed using, for example, an adhesive containing a (meth)acrylic copolymer and a cross-linking agent shown below. In addition, the adhesive may optionally contain at least one selected from a silane coupling agent, an antistatic agent, and an ultraviolet absorber, and may also contain an organic solvent.

[1.2.1] Adhesive layer composition As components constituting the adhesive layer of the present invention, resins used in adhesives can be used, or various additives can be used according to various purposes. The adhesive layer may be composed of an adhesive composition whose main component is a (meth)acrylic, rubber, urethane, ester, polysiloxane, or polyvinyl ether resin. Among them, an adhesive composition based on a (meth)acrylic resin having excellent transparency, weather resistance, heat resistance, etc. is preferred. The adhesive composition can be an active energy ray hardening type or a heat hardening type.

Moreover, the optical film of the present invention can be bonded to the display substrate through the adhesive layer. The optical film of the present invention is made of resin, and when it is bonded to a display substrate made of materials with different shrinkage rates, stress may occur in the adhesive layer. Therefore, it is preferable that the inherent birefringence value of the adhesive layer offsets the photoelasticity of the glass plate caused by the expansion and contraction stress of the resin optical film. Furthermore, it is more preferable to have a structure that offsets both the photoelasticity of the film and the photoelasticity of the glass plate caused by the expansion and contraction stress of the resin optical film.

For example, in a preferred example, the (meth)acrylic copolymer (P) and crosslinking agent (Q) described below are included as components of the adhesive layer. Furthermore, if necessary, at least one selected from a silane coupling agent and an antistatic agent may be contained, and an organic solvent may also be contained.

<(Meth)acrylic copolymer (P)> The (meth)acrylic copolymer (P) is roughly composed of three components. (P1) A component showing positive birefringence (a component that controls moisture permeability), (P2) a component that imparts crosslinking and hardening functions, and (P3) a component containing negative birefringence.

The (meth)acrylic copolymer (P) can control physical properties such as Tg and moisture permeability by suitably controlling the length of the alkyl group to a range of methyl ester to long-chain alkyl ester. It is preferable to contain alkyl methacrylate (p1) with a carbon number of 1 or more in the alkyl group in an amount ranging from 50% to 99.5% by mass, and in an amount ranging from 0% to 40% by mass. The monomer component contains the cross-linkable functional group-containing monomer (p2) in an amount within the range of 0.5 mass % or more and less than 50 mass % and contains the functional group-containing monomer (p2) containing negative birefringence. A copolymer obtained by copolymerizing the monomer components of p3). Among them, from the viewpoint of controlling the water vapor permeability, the water vapor permeability can be reduced by increasing the mixing ratio of monomers whose glass transition temperature (Tg) of the homopolymer is less than -10°C. Specifically, by setting the monomer having an alkyl group of C (carbon number) 8 or more to be 50% by mass or more, the moisture permeability can be controlled within a desired range. Examples of the monomer having an alkyl group of C8 or more include octyl methacrylate (-20°C), 2-ethylhexyl methacrylate (-10°C), and lauryl methacrylate (-65°C). ), isoctadecyl methacrylate (-18℃), etc.

More preferably, (p1) is contained in an amount ranging from 60 mass% to 90 mass%, and the crosslinkable functional group-containing monomer (p1) is contained in an amount ranging from 0 mass% to less than 40 mass%. A copolymer obtained by copolymerizing a monomer component p2) and a monomer component containing a functional group-containing monomer (P3) containing negative birefringence in an amount ranging from 5 mass % to less than 30 mass %. . Particularly preferably, (p1) is contained in an amount ranging from 65 mass % to 85 mass %, and the crosslinkable functional group-containing monomer (p1) is contained in an amount ranging from 0 mass % to less than 20 mass %. A copolymer obtained by copolymerizing a monomer component p2) and a monomer component containing a functional group-containing monomer (p3) containing negative birefringence in an amount ranging from 10 mass % to less than 20 mass %. .

In this specification, the general name of acrylic acid and methacrylic acid is also described as "(meth)acrylic acid". In addition, the structural unit derived from a certain monomer A contained in the polymer is also described as "monomer A unit". In addition, the above-mentioned (p1), (p2) and (p3) are also called "monomer (p1)", "monomer (p2)" and "monomer (p3)" respectively.

The glass transition temperature (Tg) of the homopolymer of alkyl (meth)acrylate is the value described in Polymer Handbook Fourth Edition (Wiley-Interscience 1999).

The laminated film of the present invention can be bonded to the polarizing sub-layer through an adhesive layer to form a polarizing plate. Regarding the adhesive layer, as described later ([3.3] Adhesive layer), it is preferred to use a water-based adhesive. The layer structure is in the order of release film, adhesive layer, optical film, adhesive layer, and polarizing sub-layer, and has the property that moisture contained in the adhesive layer is easily diffused into the adjacent polarizing sub-layer. Therefore, by suppressing the diffusion of moisture into the polarizing sub-layer, deterioration of the polarizing sub-layer can be prevented.

As mentioned above, since the optical film of the present invention has moisture permeability, the moisture contained in the adhesive layer easily diffuses into the optical film. In addition, since the adhesive layer of the present invention has moisture permeability, the moisture that diffuses into the optical film further diffuses into the adhesive layer, thereby further preventing the deterioration of the polarizing sub-layer. The adhesive layer of the present invention is composed of monomers (p1) and (p2), and can control moderate moisture permeability.

《Alkyl Methacrylate (p1)》 The monomer (p1) is an alkyl methacrylate whose Tg of the homopolymer is less than -10°C and the number of carbon atoms in the alkyl group is 8 or more. The Tg of the homopolymer is in the range of -80~-10°C, and the aforementioned monomer with the number of carbon atoms in the alkyl group is preferably 8 or more. The Tg is in the range of -70~-30°C, and the number of carbon atoms in the alkyl group is More preferably, the monomer has a Tg of 8 or more, and a monomer with a Tg of -70 to -30° C. and a carbon number of the alkyl group of 10 or more is particularly preferred.

By using the copolymer (P) obtained by copolymerizing the monomer (p1), it has the effect of reducing the diffusion of water into the polarizing sublayer. Therefore, by adjusting the blending ratio, a suitable water vapor transmittance can be obtained. Adhesive.

Examples of the monomer (p1) include octyl methacrylate (-20°C), isooctyl methacrylate (-45°C), 2-ethylhexyl methacrylate (-10°C), and methacrylate. Isodecyl methacrylate (-41°C), lauryl methacrylate (-65°C), myristyl methacrylate (-72°C), isoctadecyl methacrylate (-18°C). The numerical values in parentheses represent the Tg of the homopolymer of each monomer.

If a (meth)acrylic copolymer containing a structural unit derived from an alkyl methacrylate is used and the Tg of the homopolymer is low, appropriate stress relaxation properties can be imparted to the adhesive layer. In addition, when the alkyl group of alkyl methacrylate is a long-chain one, in addition to stress relaxation properties, hydrophobicity can be provided. For example, by using a monomer (p1) with a long-chain alkyl group, it has the effect of reducing the diffusion of moisture into the polarizing sublayer. Therefore, by adjusting the blending ratio, an adhesive layer with appropriate moisture permeability can be obtained. The monomer (p1) may be used individually by 1 type, or in 2 or more types.

In 100% by mass of the monomer components forming the copolymer (P), the usage amount of the monomer (p1) is not less than 50% by mass and not more than 99.5% by mass, preferably in the range of 70 to 99% by mass, and more preferably 80% by mass. Within the range of ~98.5 mass%. If the usage amount of the monomer (p1) is within the aforementioned range, it is preferable in that the resulting adhesive layer can exhibit a moderate moisture permeability function.

"Monomer (p2) containing cross-linkable functional groups" The monomer component forming the copolymer (P) includes a monomer having a crosslinkable functional group capable of reacting with the crosslinking agent (Q), that is, a crosslinkable functional group-containing monomer (p2). Examples of the monomer (p2) include a hydroxyl group-containing monomer and a carboxyl group-containing monomer.

Examples of the hydroxyl-containing monomer include hydroxyl-containing (meth)acrylate, and specific examples include 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate. , hydroxyalkyl (meth)acrylate such as 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, etc. The carbon number of the hydroxyalkyl group of the hydroxyalkyl (meth)acrylate is usually in the range of 2 to 8, preferably in the range of 2 to 6.

Examples of the carboxyl group-containing monomer include β-carboxyethyl (meth)acrylate, 5-carboxypentyl (meth)acrylate, mono(meth)acryloyloxyethyl succinate, and ω-carboxylic acid. Polycaprolactone mono(meth)acrylate and other carboxyl-containing (meth)acrylates; acrylic acid, methacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid.

In order to obtain a moderate moisture-permeable function of the adhesive layer, the above-mentioned monomer (p2) preferably has a methacrylic acid structure. One type of monomer (p2) may be used alone, or two or more types of monomers (p2) may be used.

In 100 mass% of the monomer components forming the copolymer (P), the usage amount of the monomer (p2) is 0.5 mass% or more and 10 mass% or less, preferably in the range of 1 to 8 mass%, more preferably 2 to 8 mass%. Within the range of 6% by mass. If the usage amount of the monomer (p2) is less than the above-mentioned upper limit, the crosslinking density formed by the copolymer (P) and the crosslinking agent (Q) is not too high, and an adhesive layer excellent in stress relaxation properties is obtained. If the usage amount of the monomer (p2) is more than the aforementioned lower limit, a cross-linked structure is effectively formed, and an adhesive layer having moderate strength at normal temperature is obtained.

Furthermore, the monomer (p2) is preferably set so that the acid value of the copolymer (P) is 15 or less, more preferably 10 or less, and particularly preferably 8 or less. When the acid value is equal to or less than the upper limit, deterioration of dichroic dyes such as iodine constituting polarized photons due to release of the acid can be suppressed, which is preferable.

"Functional group-containing monomer (p3) containing negative birefringence" In 100% by mass of the monomer component forming the copolymer (P), the usage amount of the monomer (p3) is from 0 to 50% by mass, preferably in the range of 5 to 45% by mass, and more preferably from 10 to 10% by mass. Within the range of 40% by mass. The usage amount of the monomer (p3) is adjusted according to the degree of birefringence of other components (p1 and p2) with positive birefringence. In addition, when used in a location where birefringence has little impact on the image quality displayed by the monitor, it may not be included. Examples of the monomer having negative birefringence include aromatic esters of (meth)acrylate. Specific examples include phenoxyethyl acrylate (PHEA), benzyl (meth)acrylate, phenoxydiethylene glycol acrylate, and ethoxylated ortho-phenylphenol acrylate (A-LEN- 10), 2-propenyloxypropyl phthalic acid, etc.

In addition, the copolymer (P) is calculated by the following formula based on the molecular weight of the carboxyl group-containing monomer used for copolymerization and the blending amount (mass %) of the carboxyl group-containing monomer. Moreover, 56.1 is the molecular weight of KOH. Acid value of polymer (mgKOH/g)=56.1/X×(Y/100)×1000 =561/X×Y X: Molecular weight of carboxyl-containing monomer Y: blending amount of carboxyl-containing monomer

"Other Individuals" As the monomer component forming the copolymer (P), for example, (meth)acrylic acid alkyl ester, (meth)acrylic acid alkyl ester other than the above-mentioned monomer (p1) can also be used as long as the physical properties of the copolymer (P) are not impaired. Alkoxyalkyl acrylate, alkoxypolyalkylene glycol mono(meth)acrylate, alicyclic group-containing (meth)acrylate, acid group-containing monomer, amine group-containing monomer, Other monomers such as amide group monomers, nitrogen-containing heterocyclic monomers, cyano group-containing monomers, etc.

The (meth)acrylic acid alkyl ester other than the monomer (p1) is represented by the formula: CH ₂ =CR ¹ -COOR ² , for example. In the formula, R ¹ is hydrogen or methyl, and R ² is an alkyl group with 1 to 18 carbon atoms. Examples include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, (meth)acrylate ) Isobutyl acrylate, tert-butyl (meth)acrylate, amyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl acrylate, octyl acrylate Ester, isooctyl acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, isodecyl acrylate, undecyl (meth)acrylate, lauryl acrylate, stearyl (meth)acrylate, Isostearyl acrylate.

Examples of (meth)acrylic acid alkoxyalkyl esters include methoxymethyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, and 2-ethoxy (meth)acrylate. Ethyl ester, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, 4-ethyl (meth)acrylate Oxybutyl ester.

Examples of alkoxy polyalkylene glycol mono(meth)acrylate include methoxydiethylene glycol mono(meth)acrylate, methoxydipropylene glycol mono(meth)acrylate, ethoxy Triethylene glycol mono(meth)acrylate, ethoxydiethylene glycol mono(meth)acrylate, methoxytriethylene glycol mono(meth)acrylate.

Examples of the (meth)acrylate containing an alicyclic group or an aromatic ring include cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, and (meth)acrylate. ) phenyl acrylate.

Examples of the acid group-containing monomer include maleic anhydride, itaconic anhydride, (meth)acrylic monomers having a phosphoric acid group in the side chain, and (meth)acrylic monomers having a sulfate group in the side chain. . Examples of the amino group-containing monomer include amino group-containing (meth)acrylate esters such as dimethylaminoethyl (meth)acrylate and diethylaminoethyl (meth)acrylate. Examples of the amide group-containing monomer include (meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl( Meth)acrylamide, N-hexyl(meth)acrylamide. Examples of the nitrogen-containing heterocyclic monomer include vinylpyrrolidone, acryloylmorpholine, and vinylcaprolactam. Examples of the cyano group-containing monomer include (meth)acrylic acid cyanoester and (meth)acrylonitrile.

In addition, as the monomer component forming the copolymer (P), copolymerizable monomers such as styrene-based monomers and vinyl acetate may be used as long as the physical properties of the copolymer (P) are not impaired.

Examples of the styrene-based monomer include styrene; methylstyrene, dimethylstyrene, trimethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene, Alkyl styrenes such as octyl styrene; halogenated styrenes such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, iodinated styrene; nitrostyrene, acetyl styrene, methyl styrene, etc. Oxystyrene. Other monomers may be used individually by 1 type, or in 2 or more types.

In 100 mass% of the monomer components forming the copolymer (P), the total usage amount of other monomers (for example: other (meth)acrylates, copolymerizable monomers) is preferably in the range of 0 to 45 mass% Within, more preferably within the range of 0~25 mass%.

"Production conditions of (meth)acrylic copolymer (P)" The production conditions of the (meth)acrylic copolymer (P) are not particularly limited. For example, the copolymer can be produced by a solution polymerization method. Specifically, the polymerization solvent and monomer components are put into the reaction vessel, the polymerization initiator is added under an inert gas environment such as nitrogen, and the reaction starting temperature is usually set in the range of 40 to 100°C, preferably 50°C. In the range of ~80°C, the reaction system is usually maintained at a temperature in the range of 50~90°C, preferably in the range of 70~90°C, and allowed to react within the range of 4 to 20 hours.

The copolymer (P) is obtained by copolymerizing a monomer component containing the above-mentioned monomers (p1) and (p2), for example, and may be a random copolymer or a block copolymer. Among these, a random copolymer is preferred.

Examples of the polymerization solvent used for solution polymerization include aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, and n-octane; and cyclopentane. , cyclohexane, cycloheptane, cyclooctane and other alicyclic hydrocarbons; diethyl ether, diisopropyl ether, 1,2-dimethoxyethane, dibutyl ether, tetrahydrofuran, di Ethers such as hexane, anisole, phenylethyl ether, diphenyl ether, etc.; halogenated hydrocarbons such as chloroform, carbon tetrachloride, 1,2-dichloroethane, chlorobenzene, etc.; ethyl acetate, Esters such as propyl acetate, butyl acetate, methyl propionate, etc.; ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, cyclohexanone, etc.; N,N-di Amides such as methylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, etc.; nitriles such as acetonitrile, benzonitrile, etc.; dimethyltrisoxide, cyclotenine, etc. The subsoil and so on. These polymerization solvents may be used individually by 1 type, or in 2 or more types.

Examples of the polymerization initiator used for solution polymerization include azo-based initiators and peroxide-based initiators. Specific examples include azo compounds such as 2,2'-azobisisobutyronitrile and peroxides such as benzoyl peroxide and lauryl peroxide. Among these, azo compounds are preferred. Examples of azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2, 2'-Azobis(2-cyclopropylpropionitrile), 2.2'-Azobis(2,4-dimethylvaleronitrile), 2,2'-Azobis(2-methylbutyronitrile) , 1,1'-azobis(cyclohexane-1-carbonitrile), 2-(aminomethyl azo)isobutyronitrile, 2-phenylazo-4-methoxy-2,4 -Dimethylvaleronitrile, 2,2'-Azobis(2-formamidinopropane) dihydrochloride, 2,2'-Azobis(N,N'-dimethyleneisobutylamidine) ), 2,2'-Azobis[2-methyl-N-(2-hydroxyethyl)-propionamide], 2,2'-Azobis(isobutylamide) dihydrate, 4,4'-Azobis(4-cyanopentanoic acid), 2,2'-Azobis(2-cyanopropanol), dimethyl-2,2'-azobis(2- Methylpropionate), 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide]. These polymerization initiators may be used individually by 1 type, or in 2 or more types.

The polymerization initiator is usually in the range of 0.01 to 5 parts by mass, preferably in the range of 0.1 to 3 parts by mass relative to 100 parts by mass of the monomer component forming the (meth)acrylic copolymer (P). use. Moreover, in the above-mentioned polymerization reaction, a polymerization initiator, a chain transfer agent, a monomer component, and a polymerization solvent can be added appropriately.

"Physical properties and content of (meth)acrylic copolymer (P)" The weight average molecular weight (Mw) of the (meth)acrylic copolymer (P) measured by gel permeation chromatography (GPC) is a polystyrene-converted value, and is usually in the range of 400,000 to 3 million. Within, preferably within the range of 600,000 to 2.5 million, more preferably within the range of 800,000 to 2,000,000, particularly preferably within the range of 800,000 to 1.3 million. By using a copolymer (P) with an Mw within the above range and having the above monomer units, it has the effect of reducing the diffusion of moisture into the polarizing sublayer. Therefore, the mixing ratio of the copolymer (P) can be selected to exhibit appropriate moisture permeability. . Furthermore, it is easy to achieve a balance of adhesion and can be used as an adhesive with a viscosity suitable for coating.

The molecular weight distribution (Mw/Mn) of the (meth)acrylic copolymer (P) measured by the GPC method is usually 15 or less, preferably within the range of 2 to 15, more preferably within the range of 4 to 13 .

The glass transition temperature (Tg) of the (meth)acrylic copolymer (P) can be estimated by Fox's equation from the monomer units constituting the copolymer and their content ratio, for example. The (meth)acrylic system can be synthesized so that the glass transition temperature (Tg) calculated by Fox's formula is usually in the range of -80 to -20°C, and preferably in the range of -70 to -30°C. Copolymer (P). By using the (meth)acrylic copolymer (P) having such a glass transition temperature (Tg), an adhesive having excellent stress relaxation and durability and excellent adhesion at room temperature can be obtained.

In the formula, Tg is the glass transition temperature of the (meth)acrylic copolymer (P), Tg ₁ , Tg ₂ , ..., Tg _m is the glass transition temperature of the homopolymer composed of each monomer, W ₁ , W ₂ , ..., W _m are the mass fractions of the structural units derived from each monomer in the copolymer (P). As the mass fraction of the structural units derived from each monomer, the feed ratio of each monomer to all monomers at the time of copolymer synthesis can be used.

The glass transition temperature of the homopolymer composed of each monomer in the Fox formula can be the value described in the Polymer Handbook Fourth Edition (Wiley-Interscience 1999), for example.

In the adhesive used in the present invention, the content of the (meth)acrylic copolymer (P) is based on 100% by mass of the solid content other than the organic solvent in the adhesive, and is usually in the range of 60 to 99.99% by mass. Preferably, it is in the range of 70 to 99.95 mass%, and particularly preferably, it is in the range of 80 to 99.90 mass%. When the content of the (meth)acrylic copolymer (P) is within the above range, the performance as an adhesive is balanced and the adhesiveness is excellent.

[1.2.2] Cross-linking agent ＜Cross-linking agent (Q)＞ The adhesive used in the present invention further contains a cross-linking agent (Q). The cross-linking agent (Q) is a component capable of causing a cross-linking reaction with the cross-linking functional group derived from the cross-linking functional group-containing monomer (p2) of the (meth)acrylic copolymer (P). , there are no particular limitations, and examples thereof include isocyanate compounds (Q1), metal chelate compounds (Q2), and epoxy compounds (Q3). The cross-linking agent (Q) may be used individually by 1 type, or in 2 or more types.

In the adhesive used in the present invention, the content of the cross-linking agent (Q) is usually 0.01 to 5 parts by mass, preferably 0.05 to 2.5 parts by mass relative to 100 parts by mass of the (meth)acrylic copolymer (P). parts, preferably 0.1~1 parts by mass. If the content is within the above range, it is preferable because a balance between durability and stress relaxation properties can be easily achieved.

《Isocyanate compound (Q1)》 As the isocyanate compound (Q1), an isocyanate compound having 2 or more isocyanate groups per molecule is usually used. The (meth)acrylic copolymer (P) is cross-linked with the isocyanate compound (Q1) to form a cross-linked body (network polymer).

The number of isocyanate groups of the isocyanate compound (Q1) is usually 2 or more, preferably in the range of 2 to 8, more preferably in the range of 3 to 6. If the number of isocyanate groups is within the above range, it is preferable in terms of the efficiency of the cross-linking reaction between the (meth)acrylic copolymer (P) and the isocyanate compound (Q1) and the point of maintaining the flexibility of the adhesive layer.

Examples of the diisocyanate compound having 2 isocyanate groups per molecule include aliphatic diisocyanate, alicyclic diisocyanate, and aromatic diisocyanate. Examples of aliphatic diisocyanates include ethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 2-methyl-1,5-pentane diisocyanate, Aliphatic diisocyanates with 4 to 30 carbon atoms such as 3-methyl-1,5-pentane diisocyanate and 2,2,4-trimethyl-1,6-hexamethylene diisocyanate. Examples of the alicyclic diisocyanate include isophorone diisocyanate, cyclopentyl diisocyanate, cyclohexyl diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated toluene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated Alicyclic diisocyanates with 7 to 30 carbon atoms such as tetramethylxylene diisocyanate. Examples of the aromatic diisocyanate include phenylene diisocyanate, toluene diisocyanate, xylylene diisocyanate, naphthylene diisocyanate, diphenyl ether diisocyanate, diphenylmethane diisocyanate, and diphenyl diisocyanate. Aromatic diisocyanates with 8 to 30 carbon atoms such as propane diisocyanate.

Examples of the isocyanate compound having 3 or more isocyanate groups per molecule include aromatic polyisocyanate, aliphatic polyisocyanate, and alicyclic polyisocyanate. Specific examples include 2,4,6-triisocyanatotoluene, 1,3,5-triisocyanatobenzene, and 4,4',4″-triphenylmethane triisocyanate.

Examples of the isocyanate compound (Q1) include polymers of the isocyanate compounds having an isocyanate group number of 2 or 3 or more (for example, dimers, trimers, biurets, and isocyanate bodies). ), derivatives (such as the addition reaction product of a polyol and two or more molecules of a diisocyanate compound), and polymers. Examples of the polyhydric alcohol in the derivatives include trimethylolpropane, glycerin, pentaerythritol, and other alcohols having a trivalent or higher valence among low-molecular-weight polyols. Examples of the high-molecular-weight polyol include polyether polyhydric alcohols. Alcohol, polyester polyol, acrylic polyol, polybutadiene polyol, polyisoprene polyol.

Examples of such an isocyanate compound include a trimer of diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, hexamethylene diisocyanate, or a biuret or isotrimer of toluene diisocyanate. Cyanate body, the reaction product of trimethylolpropane and toluene diisocyanate or xylylene diisocyanate (such as the 3-molecule adduct of toluene diisocyanate or xylylene diisocyanate), trimethylolpropane Reaction product with hexamethylene diisocyanate (for example, 3-molecule adduct of hexamethylene diisocyanate), polyether polyisocyanate, polyester polyisocyanate.

Among the isocyanate compounds (Q1), in terms of improving curability, the reaction product of trimethylolpropane and toluene diisocyanate or xylylene diisocyanate (L- manufactured by Soken Chemical Co., Ltd. 45. TD-75, etc. manufactured by Soken Chemical Co., Ltd.), isocycyanurate body of hexamethylene diisocyanate or toluene diisocyanate (TSE-100 manufactured by Asahi Kasei Co., Ltd., Japan Polyurethane Industry (Stock) System 2050, etc.). The isocyanate compound (Q1) may be used individually by 1 type, and may be used in 2 or more types.

《Metal chelate compound (Q2)》 Examples of the metal chelate compound (Q2) include alkoxides coordinated to polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, zirconium, etc. Compounds made of acetyl acetone, acetyl ethyl acetate, etc.

Among these, aluminum chelate compounds (such as M-12AT manufactured by Soken Chemical Co., Ltd.) are particularly preferred. Specific examples include aluminum isopropionate, secondary aluminum butyrate, aluminum ethyl acetyl acetate-diisopropionate, aluminum triethyl acetyl acetate, and aluminum triacetyl pyruvate. A metal chelate compound (Q2) may be used individually by 1 type, and may be used in 2 or more types.

The metal chelate compound (Q2) cross-links (pseudo-cross-links) the (meth)acrylic copolymer (P) through coordination bonds. When a metal chelate compound (Q2) is used as the cross-linking agent (Q), the cross-linking is maintained at room temperature and the polymer exhibits cohesiveness. However, at high temperatures, a part of the cross-linking is dissociated and the adhesive layer exhibits better performance. of softness.

《Epoxy compound(Q3)》 As the epoxy compound (Q3), an epoxy compound having 2 or more epoxy groups per molecule is usually used. For example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,3-bis(N, N-diepoxypropylaminomethyl)cyclohexane, N,N,N',N'-tetraepoxypropyl-m-xylylenediamine, N,N,N',N' -Tetraepoxypropylaminophenylmethane, tripoxypropylisocyanurate, m-N,N-diepoxypropylaminophenylepoxypropyl ether, N,N-diepoxy Propyltoluidine, N,N-diepoxypropylaniline.

[1.2.3]Additives ＜Silane Coupling Agent＞ The adhesive used in the present invention preferably further contains a silane coupling agent. The silane coupling agent makes the adhesive layer firmly adhere to adherends such as glass plates and helps prevent peeling in high temperature and high humidity environments.

Examples of the silane coupling agent include polymerizable unsaturated group-containing silane coupling agents such as vinyltrimethoxysilane, vinyltriethoxysilane, and methacryloxypropyltrimethoxysilane; 3- Glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyloxysilane Epoxy group-containing silane coupling agents such as methylpropylmethyldiethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; 3-aminopropyltrimethoxysilane Silane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, etc. Amino-containing silane coupling agents; halogen-containing silane coupling agents such as 3-chloropropyltrimethoxysilane, 3-oxobutyric acid-3-(trimethoxysilyl)propyl ester and oligomer silane Coupling agent, etc. Among them, those having functional groups that react with functional groups contained in the (meth)acrylic copolymer (P) to form covalent bonds or can form bonds by interacting with the (meth)acrylic copolymer (P) Silane coupling agents with functional groups are preferred because they are less likely to peel off in high temperature and high humidity environments.

In the adhesive used in the present invention, the content of the silane coupling agent is usually 1 part by mass or less, preferably within the range of 0.01 to 1 part by mass, relative to 100 parts by mass of the (meth)acrylic copolymer (P). More preferably, it is in the range of 0.05~0.5 parts by mass. If the content is within the above range, peeling in a high temperature and high humidity environment or exudation of the silane coupling agent in a high temperature environment tends to be prevented.

＜Antistatic agent＞ Antistatic agents can be used, for example, to reduce the surface resistance of the adhesive layer of the present invention. Examples of antistatic agents include surfactants, ionic compounds, and conductive polymers.

Examples of surfactants include quaternary ammonium salts, amide quaternary ammonium salts, pyridinium salts, cationic surfactants having cationic groups such as primary to tertiary amine groups; cationic surfactants having sulfonic acid Anionic surfactants with anionic bases such as salt base, sulfate ester base, and phosphate ester base; alkyl betaines, alkyl imidazolium betaines, alkyl amine oxides, and amino acid sulfates Such amphoteric surfactants, glycerin fatty acid esters, sorbitan fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene alkylamine fatty acid esters, N-hydroxyethyl-N-2-hydroxy Nonionic surfactants such as alkyl amines and alkyl diethanol amides.

In addition, examples of the surfactant include reactive emulsifiers having a polymerizable group, and a polymer-based interface obtained by polymerizing a monomer component including the above-mentioned surfactant or reactive emulsifier can also be used. active agent. The ionic compound is composed of a cation part and an anion part, and can be either solid or liquid at room temperature (23° C., 50% RH).

The cation portion constituting the ionic compound may be either an inorganic cation or an organic cation, or both. As the inorganic cation, an alkali metal ion and an alkaline earth metal ion are preferred, and Li ⁺ , Na ⁺ and K ⁺ having excellent antistatic properties are more preferred. Examples of organic cations include pyridinium cation, piperidinium cation, pyrrolidinium cation, pyrroline cation, pyrrole cation, imidazolium cation, tetrahydropyrimidinium cation, dihydropyrimidinium cation, and pyrazolium cation. , pyrazolinium cations, tetraalkyl ammonium cations, trialkyl sulfonium cations, tetraalkyl phosphonium cations and their derivatives.

The anionic part constituting the ionic compound is not particularly limited as long as it can ionically bond with the cationic part to form an ionic compound. Specific examples include F ^- , Cl ^- , Br ^- , I ^- , AlCl ₄ ^- , Al ₂ Cl ₇ ^- , BF ₄ ^- , PF ₆ ^- , SCN ^- , ClO ₄ ^- , NO ₃ ^- and CH ₃ COO ^- , CF ₃ COO ^- , CH ₃ SO ₃ ^- , CF ₃ SO ₃ ^- , (CF ₃ SO ₂ ) ₂ N ^- , (F ₂ SO ₂ ) ₂ N ^- , (CF ₃ SO ₂ ) ₃ C ^- , AsF ₆ ^- , SbF ₆ ^- , NbF ₆ ^- , TaF ₆ ^- , F(HF) _n ^- , (CN) ₂ N ^- , C ₄ F ₉ SO ₃ ^- , (C ₂ F ₅ SO ₂ ) ₂ N ^- , C ₃ F ₇ COO ^- and (CF ₃ SO ₂ )(CF ₃ CO)N ^- . Among these, anions containing fluorine atoms are preferred because they provide ionic compounds with low melting points, and (F ₂ SO ₂ ) ₂ N ^- and (CF ₃ SO ₂ ) ₂ N ^- are particularly preferred because they are less likely to occur. Regarding the degradation point of the polarizing sub-layer, (CF ₃ SO ₂ ) ₂ N ^- is particularly preferred.

As the ionic compound, preferred are lithium bis(trifluoromethanesulfonyl)imide, lithium bis(difluoromethanesulfonyl)imide, lithium bis(trifluoromethanesulfonyl)methane, potassium bis( Trifluoromethanesulfonyl)imide, potassium bis(difluorosulfonyl)imide, 1-ethylpyridinium hexafluorophosphate, 1-butylpyridinium hexafluorophosphate, 1-hexyl- 4-methylpyridinium hexafluorophosphate, 1-octyl-4-methylpyridinium hexafluorophosphate, 1-octyl-4-methylpyridinium bis(fluorosulfonyl)imide, 1 - Octyl-4-methylpyridinium bis(trifluoromethanesulfonyl)imide, tributylmethylammonium bis(fluorosulfonyl)imide, tributylmethylammonium bis(trifluoromethanesulfonyl)imide ) acyl imine, (N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium tetrafluoroborate, N,N-diethyl-N-methyl-N -(2-Methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide, 1-octylpyridinium fluorosulfonium imide, 1-octyl-3-methylpyridinium, trifluoride sulfide imine. Examples of the conductive polymer include polythiophene, polyaniline, polypyrrole, and derivatives thereof.

In the adhesive used in the present invention, the content of the antistatic agent is usually 3 parts by mass or less relative to 100 parts by mass of the (meth)acrylic copolymer (P), preferably within the range of 0.01 to 3 parts by mass. , preferably within the range of 0.05~2.5 parts by mass.

＜Organic solvent＞ The adhesive used in the present invention preferably contains an organic solvent in order to adjust the coating properties. Examples of the organic solvent include the polymerization solvents described in the column for (meth)acrylic copolymer (P). For example, the polymer solution containing the (meth)acrylic copolymer (P) obtained by the above copolymerization and the polymerization solvent and the cross-linking agent (Q) can be mixed to prepare an adhesive. In the adhesive used in the present invention, the content of the organic solvent is usually in the range of 50 to 90 mass%, preferably in the range of 60 to 85 mass%.

In addition, the so-called "solid content" in this specification refers to all the components in the adhesive except the above-mentioned organic solvent, and the so-called "solid content concentration" refers to the ratio of the aforementioned solid content to 100% by mass of the adhesive. .

＜Other additives＞ In addition to the above ingredients, the adhesive used in the present invention may also contain antioxidants, light stabilizers, ultraviolet absorbers, metal corrosion inhibitors, thickeners, and plasticizers within the scope that does not impair the effects of the present invention. , crosslinking accelerator, (meth)acrylic polymers other than the aforementioned (P), and one or more selected from the group consisting of reprocessing agents.

[1.2.4] Physical properties <Water vapor transmission rate> The water vapor transmission rate of the adhesive layer system of the present invention is preferably 800g/ ^m2 ·day or more and 5000/ ^m2 ·day or less, more preferably 1000~4000g/ ^m2 · Day or less, preferably 1500~3500g/m ² ·day. The method for measuring the above-mentioned water vapor transmittance will be described in detail in the column of Examples below.

When the water vapor transmittance is in the above range, it is preferable from the viewpoint of the durability of the bonding layer formed when the optical film and the polarizing sub-layer are bonded together. By setting the moisture permeability of the adhesive layer to 800g/m ² ·day or more, the moisture and solvent contained in the adhesive layer become easier to diffuse from the optical film side to the adhesive layer, and the adhesive durability is improved. On the other hand, if it is 5000g/m ² ·day or less, the adhesive layer will be less likely to absorb moisture and expand, and the adhesion durability will be excellent against dimensional changes. Furthermore, the adhesive layer of the present invention prevents the polarizer layer from shrinking and preventing cracks from occurring even in high-temperature and high-humidity environments.

The water vapor transmittance of the adhesive layer is higher than the water vapor transmittance of the optical film, which is preferable from the viewpoint of the durability of the bonding layer formed when the optical film and the polarizing sub-layer are bonded. By making the water vapor transmittance of the adhesive layer higher than the water vapor transmittance of the optical film, moisture and solvents become easier to diffuse from the optical film side to the adhesive layer.

＜Adhesion＞ The adhesion of the laminated film of the present invention to the substrate can be measured according to the "Adhesive tape and adhesive sheet test method" described in JIS Z-0237:2009. From the perspective of durability against repeated folding movements when bonded to the substrate, the adhesion force to the substrate is preferably 3.0N/25mm or more, more preferably 4.0N/25mm or more, and particularly preferably 4.5N/25mm. above. The substrate is not particularly limited, but is preferably a glass plate or thermoplastic resin. The method for measuring the above-mentioned adhesive force will be explained in detail in the column of Examples below.

[1.3] Release film The release film of the present invention is not particularly limited, but a release film having a release layer formed on a transparent base film is usually used. As the transparent base film, various resin films can be used in the same manner as the support used when producing the optical film described later, but a polyester film is preferred. The polyester film may be composed of a single layer or a laminated structure.

[1.3.1] Release film components ＜Polyester film＞ The polyester used in the polyester film may be homopolyester or copolymerized polyester. When it is composed of homopolyester, it is preferably one obtained by polycondensation of aromatic dicarboxylic acid and aliphatic diol. Examples of aromatic dicarboxylic acids include terephthalic acid, 2,6-naphthalenedicarboxylic acid, and the like, and examples of aliphatic diols include ethylene glycol, diethylene glycol, and 1,4-cyclohexane. Dimethyl alcohol, etc. Typical polyesters include polyethylene terephthalate (PET) and the like. On the other hand, examples of the dicarboxylic acid component of the copolymerized polyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, One or two or more hydroxycarboxylic acids (such as p-hydroxybenzoic acid, etc.). Examples of glycol components include ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, and 1,4-cyclohexanediol. One or more of methanol, neopentyl glycol, etc. In any case, the polyester mentioned in the present invention refers to polyesters such as polyethylene terephthalate in which usually 60 mol% or more, preferably 80 mol% or more, are ethylene terephthalate units.

In the present invention, it is preferable to blend particles with the main purpose of imparting slipperiness into the polyester layer. The type of particles to be blended is not particularly limited as long as they can provide slipperiness. Specific examples include silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, and phosphoric acid. Particles of magnesium, kaolin, aluminum oxide, titanium oxide, etc. In addition, heat-resistant organic particles described in Japanese Patent Publication No. 59-5216, Japanese Patent Publication No. 59-217755, etc. can also be used. Examples of other heat-resistant organic particles include thermosetting urea resin, thermosetting phenol resin, thermosetting epoxy resin, benzoguanamine resin, and the like. Furthermore, in the polyester production step, precipitated particles obtained by precipitating and finely dispersing a part of a metal compound such as a catalyst can also be used.

On the other hand, the shape of the particles used is not particularly limited, and any of spherical, lumpy, rod-shaped, flat, etc. may be used. In addition, there are no special restrictions on its hardness, specific gravity, color, etc. These series of particle systems may be used in combination of two or more types as necessary.

The surface roughness (SRa) of the release film in the present invention is usually in the range of 10 to 30 nm, preferably in the range of 10 to 20 nm, from the viewpoint of the sliding properties and appearance of the film.

The average particle size of the particles contained in the polyester film is usually in the range of 0.2 to 1 μm. When the particle size is 0.2 μm or more, flattening of the film surface can be prevented and deterioration of winding characteristics in the film manufacturing process can be prevented. When the particle diameter is 1 μm or less, the particles provided in order to provide sliding properties do not form protrusions protruding from a part of the release film, and the uniformity of the layer thickness of the adhesive layer that becomes the adjacent layer in the present invention improves the adhesiveness. It is more suitable from the viewpoint of adhesion durability.

In addition, the particle content in the polyester layer is usually in the range of 0.01 to 3% by mass, which is preferable from the viewpoint of slipperiness and transparency of the film.

There is no particular limitation on the method of adding particles to the polyester layer, and conventional methods can be used. For example, it can be added at any stage of manufacturing the polyester constituting each layer, but it is preferable to perform the polycondensation reaction at the stage of esterification or after completion of the transesterification reaction.

In addition, a method of blending a slurry of particles dispersed in ethylene glycol, water, etc. and polyester raw materials by using a kneading extruder with an exhaust port, or using a kneading extruder to blend dried The method of using particles and polyester raw materials is carried out.

Furthermore, in addition to the above particles, conventional antioxidants, antistatic agents, heat stabilizers, lubricants, dyes, pigments, etc. may be added as necessary to the polyester film in the present invention.

The thickness of the polyester film constituting the release film of the present invention is preferably in the range of 30 to 75 μm in order to achieve good handleability for use. When the film thickness is 30 μm or more, even if the polarizing plate is further thinned, the strength of the film laminate will not be insufficient and the operability will not be reduced. On the other hand, in the case of 75 μm or less, the cost-effectiveness is good, the length of the roll in the roll-shaped product will not become difficult, and the workability will not be reduced in continuous production.

＜Mold release layer＞ The release layer constituting the release film of the present invention preferably contains a curable polysiloxane resin from the viewpoint of achieving good release properties. It can be a type with hardened polysilicone resin as the main component, or modified polysiloxane made by graft polymerization with organic resins such as urethane resin, epoxy resin, alkyd resin, etc. Type etc.

As the type of curable polysilicone resin, any curing reaction type such as addition type, condensation type, ultraviolet curing type, electron beam curing type, solvent-free type, etc. can be used. Specific examples include KS-774, KS-775, KS-778, KS-779H, KS-847H, KS-856, X-62-2422, X-62-2461, manufactured by Shin-Etsu Chemical Industry Co., Ltd. X-62-1387, X-62-5039, X-62-5040, KNS-3051, X-62-1496, KNS320A, KNS316, 7028A/B, X-62-7619, A2982, UV9430, TPR6600, TPR6604, TPR6605, Toray-Dow Corning Co., Ltd. SRX357, SRX211, SD7220, SD7292, LTC750A, LTC760A, LTC303E, SP7259, BY24-468C, SP7248S, BY24-452, DKQ3 -202、DKQ3- 203, DKQ3-204, DKQ3-205, DKQ3-210, etc. Furthermore, in order to adjust the peelability of the release layer, a peeling control agent may be used together.

[1.4] Manufacturing method of laminated film The laminated film of the present invention is a laminated film composed of at least an optical film, an adhesive layer and a release film, and is characterized in that the thickness of the optical film is in the range of 1 to less than 10 μm, and the thickness of the adhesive layer is 1 ~Within the range of less than 10μm. The form of the laminated film of the present invention is not particularly limited. Before being actually used for various purposes, it may be in the form of a strip, for example. That is, the laminated film of the present invention is preferably rolled into a roll shape in a direction orthogonal to its width direction to form a roll body.

The laminated film of the present invention can be obtained by, for example, forming an optical film on a support and then sequentially laminating an adhesive layer and a release film.

Alternatively, an adhesive layer may be formed after forming the release film, and may be bonded to the optical film formed on the support. Details of this manufacturing method are shown below.

[1.4.1] Manufacturing method of optical film The optical film of the present invention is formed on a support. The manufacturing method includes: (1) the steps of obtaining a solution for optical films, (2) the steps of applying the obtained solution for optical films to the surface of a support, and (3) removing the solvent from the applied solution for optical films, Steps for forming optical films.

(1) Steps to obtain solution for optical films An optical film solution (also referred to as "dope") containing the aforementioned resin and solvent is prepared.

The solvent used in the optical film solution is not particularly limited as long as it can disperse or dissolve the resin well. For example, examples of organic solvents used in the present invention include alcohols (methanol, ethanol, glycols, triols, tetrafluoropropanol, etc.), glycols, cellulose, and ketones (acetone, methyl ethyl alcohol, etc.). Ketones, etc.), carboxylic acids (formic acid, acetic acid, etc.), carbonates (ethyl carbonate, propyl acetate, etc.), esters (ethyl acetate, propyl acetate, etc.), ethers (isopropyl ether, etc.) , THF, etc.), amides (dimethylstyrene, etc.), hydrocarbons (heptane, etc.), nitriles (acetonitrile, etc.), aromatics (cyclohexylbenzene, toluene, xylene, chlorobenzene, etc.), Halogenated alkyls (dichloromethane (also known as "methylene chloride"), etc.), amines (1,4-diazabicyclo[2.2.2]octane, diazabicycloundecene, etc.) , lactone series, etc.

Among them, a chlorine-based solvent with a boiling point of 100° C. or less under atmospheric pressure is preferable from the viewpoint of ease of handling when preparing a coating liquid for an optical film and forming the film. Specifically, methylene chloride (also known as "methylene chloride") is preferred. Methylene chloride has high resin solubility and fast drying speed, so it is easy to adjust the film quality of the coating film. In addition, hydrophilic materials can be added Hydrophilic solvents include ketones and alcohols, preferably alcohols, more preferably isopropanol, ethanol, methanol, etc., and most preferably methanol. The preferred addition amount is 1 to 20 Within the range of mass %, more preferably within the range of 3 to 10 mass %.

The resin concentration of the optical film solution is preferably within the range of 1.0 to 20% by mass, for example, from the viewpoint of easily adjusting the viscosity to the range described below. Furthermore, from the viewpoint of reducing the amount of shrinkage of the coating film during drying, the resin concentration of the optical film solution is preferably moderately high, more preferably more than 5% by mass and less than 20% by mass, and particularly preferably more than 5% by mass. % and less than 15% by mass. In addition, by adjusting the solution concentration, the time until the film is formed is shortened, and the drying time can also be used as a means to control the surface state of the optical film. In order to increase the concentration, a mixed solvent may be suitably used.

The viscosity of the optical film solution is not particularly limited as long as it can form an optical film with a desired thickness, but for example, it is preferably in the range of 5 to 5000 mPa·s. If the viscosity of the optical film solution is 5 mPa·s or more, it is easy to form an optical film with an appropriate thickness. If it is 5000 mPa·s or less, the viscosity of the solution increases, thereby suppressing uneven thickness. From the same point of view, the viscosity of the optical film solution is preferably in the range of 100 to 1000 mPa·s. The viscosity of the optical film solution can be measured with an E-type viscometer at 25°C.

(2) Steps for applying solution for optical films Next, the obtained optical film solution is applied to the surface of the support. Specifically, the obtained optical film solution is applied to the surface of the support.

＜Support＞ The support system supports the optical film when it is formed, and a resin film is usually used. The thickness of the support body is preferably 50 μm or less. The thickness of the support body requires a certain degree of strength (stiffness or rigidity) as the support body, so it is preferably in the range of 15 to 45 μm, and more preferably in the range of 20 to 40 μm.

Examples of the resin used include cellulose ester resins, cycloolefin resins, polypropylene resins, acrylic resins, polyester resins, polyarylate resins, styrene resins, or composite resins thereof. Among them, As a resin excellent in storage properties in a high-humidity environment, it is preferable to use a polyester-based resin.

Examples of resin films include polyester resins (such as polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), Polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), etc.). Among them, from the viewpoint of ease of handling, a polyester-based resin film containing polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) is preferred.

The resin film can be heat-treated (heat-relaxed) or stretched.

The heat treatment is performed in order to reduce the residual stress of the resin film (such as the residual stress caused by stretching, etc.) and is not particularly limited. However, when the glass transition temperature of the resin constituting the resin film is regarded as Tg, it can be between (Tg+60)~ (Tg+180)℃.

In order to increase the residual stress of the resin film, the stretching treatment is preferably performed in the biaxial directions of the resin film, for example. The stretching process can be performed under any conditions, for example, the stretching ratio can be about 120~900%. Whether the resin film is stretched can be confirmed by, for example, whether or not there is an in-plane slow axis (an axis extending in the direction in which the refractive index is maximum). The stretching treatment may be performed before the optical film is laminated, or after the lamination, but it is preferably performed before the lamination.

Commercially available polyester resin films (also simply called polyester films) can be used, and examples include "Polyethylene terephthalate film TN100" manufactured by Toyobo Co., Ltd. and "MELINEX" manufactured by Teijin DuPont Film Co., Ltd. ST504" etc.

The support may have a release layer on the surface of the resin film. The peeling layer can easily peel the support from the optical film when producing a polarizing plate.

The release layer may contain a well-known release agent and is not particularly limited. Examples of the release agent contained in the release layer include polysilicone-based release agents and non-polysilicone-based release agents.

Examples of polysilicone-based release agents include well-known polysilicone-based resins. Examples of non-silicone release agents include long-chain alkyl hanging polymers obtained by reacting long-chain alkyl isocyanates with polyvinyl alcohol or ethylene-vinyl alcohol copolymers, and olefin-based resins (such as Copolymerized polyethylene, cyclic polyolefin, polymethylpentene), polyarylate resin (such as the polycondensate of aromatic dicarboxylic acid components and dihydric phenol components), fluororesins (such as polytetrafluoroethylene (PTFE) ), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), PFA (copolymer of tetrafluoroethylene and perfluoroalkoxyethylene), FEP (copolymer of tetrafluoroethylene and hexafluoropropylene), ETFE (Copolymer of tetrafluoroethylene and ethylene)) etc.

The thickness of the peeling layer is not particularly limited as long as it can exhibit desired peelability, but for example, it is preferably in the range of 0.1 to 1.0 μm.

The support may also contain plasticizers as additives. The plasticizer is not particularly limited, but is preferably selected from the group consisting of polyol ester plasticizers, phthalate ester plasticizers, citric acid plasticizers, fatty acid ester plasticizers, and phosphate ester plasticizers. agents, polycarboxylate plasticizers and polyester plasticizers, etc.

Moreover, the support may contain an ultraviolet absorber. Examples of ultraviolet absorbers include benzotriazole-based, 2-hydroxybenzophenone-based, or phenyl salicylate-based ones. For example, 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]- 2H-benzotriazole, 2-(3,5-di-tert-butyl-2-hydroxyphenyl)benzotriazole and other triazoles, 2-hydroxy-4-methoxybenzophenone, Benzophenones such as 2-hydroxy-4-octoxybenzophenone and 2,2'-dihydroxy-4-methoxybenzophenone.

Furthermore, the support used in the present invention preferably contains fine particles in order to improve transportability.

The fine particles are preferably those using an inorganic compound. Examples thereof include silica, titanium dioxide, alumina, zirconium oxide, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, and hydrated calcium silicate. Aluminum silicate, magnesium silicate and calcium phosphate. It is also preferable to use fine particles of organic compounds. Examples include polytetrafluoroethylene, cellulose acetate, polystyrene, polymethyl methacrylate, polypropyl methacrylate, and polymethyl acrylate. Ester, polyethylene carbonate, acrylic styrene resin, polysiloxane resin, polycarbonate resin, benzoguanamine resin, melamine resin, polyolefin powder, polyester resin, polyamide resin Resins, polyimide-based resins, polyvinyl fluoride-based resins, pulverized fractions of organic polymer compounds such as starch, or polymer compounds synthesized by suspension polymerization.

From the viewpoint of lowering the turbidity, the fine particles preferably contain silicon. Particularly preferred is silicon dioxide, and examples include "Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (trade name)" manufactured by Nippon Aerosil Co., Ltd.

As a manufacturing method of the support used in the present invention, ordinary manufacturing methods such as inflation method, T-die method, calendering method, cutting method, casting method, emulsification method, hot pressing method, etc. can be used. From the viewpoint of optical defects such as foreign matter defects and suppression of die lines, the preferred film forming methods are solution casting and melt casting. Furthermore, in the solution casting method, the temperature of the processing step is low, so it is possible to provide high functionality by using various additives.

When forming a film by a solution casting method, the manufacturing method of the support preferably includes a step of dissolving and dispersing the thermoplastic resin and additives such as the above-mentioned fine particles in a solvent to prepare a coating liquid (dissolving step; coating liquid preparation step) ), the step of casting the coating liquid on an infinitely moving endless metal support (casting step), the step of drying the cast coating liquid into a sheet (solvent evaporation step), and peeling it off from the metal support step (peeling step), drying, stretching, and width maintaining steps (stretching, width maintaining, drying step), and rolling the processed film into a roll (winding step).

It is preferable to use the support produced as above and form the optical film of the present invention by the following method.

The coating method of the optical film solution is not particularly limited, and may be well-known methods such as back roll coating, gravure coating, spin coating, wire bar coating, and roll coating. Especially from the viewpoint of being able to form a thin and uniform thickness coating film, the back coating method is preferred.

(3) Steps to form optical films Next, the solvent is removed from the optical film solution applied to the support to form an optical film.

Specifically, the solution for the optical film applied to the support is dried. Drying can be performed by blowing air or heating, for example. Among them, from the viewpoint of easily suppressing curling of the optical film, drying by air blowing is preferred, and in order to control film thickness variation described below, it is preferred to create a difference in wind speed between the initial stage of drying and the second half of drying. Specifically, when the initial wind speed is high, the film thickness deviation tends to become larger, and when the initial wind speed is low, the film thickness deviation tends to become smaller.

Therefore, by adjusting drying conditions (such as drying temperature, drying air volume, drying time, etc.) to suppress the density of the optical film, the thickness of the optical film can be adjusted to satisfy the above formula 1.

The thickness deviation of the aforementioned optical film is preferably adjusted to a range of 0.5±0.2 μm. It is preferable to adjust the film quality in the direction of thinning from the perspective of improving the adhesion with the upper layer. Specifically, it is preferable to increase the drying speed, preferably within the range of 0.0015~0.05kg/hr·m ² , preferably within the range of 0.002 ~0.05kg/hr·m ² .

Drying speed is expressed in terms of the mass of solvent evaporated per unit time and unit area. Drying speed can usually be adjusted by drying temperature. The drying temperature also depends on the type of solvent used, but may be, for example, 50 to 200°C ((Tb-50) to (Tb+50)°C relative to the boiling point Tb of the solvent used). The temperature control system can be carried out in multiple stages. After drying to a certain extent, drying at a higher temperature can control the drying speed and film quality.

The optical film according to this embodiment may be in the form of a strip as described above. Therefore, it is preferable that the manufacturing method of the laminated film of this embodiment further includes the step of (4) winding the strip-shaped laminated film into a roll shape, and making it into a roll body.

(4) Steps of rolling up the optical film to obtain a roll body The obtained strip-shaped optical film is rolled into a roll in a direction orthogonal to its width direction to form a roll.

The length of the strip-shaped optical film is not particularly limited, but may be about 100 to 10,000 m, for example. In addition, the width of the strip-shaped optical film is preferably 1 m or more, more preferably within the range of 1.1 to 4 m. From the viewpoint of improving the uniformity of the film, the range is more preferably within the range of 1.3~2.5m.

＜Manufacturing equipment＞ The manufacturing method of the optical film used in the present invention can be carried out by, for example, the manufacturing apparatus shown in FIG. 2 .

2 is a model diagram of a manufacturing device B200 for implementing the manufacturing method of the optical film of the present invention. The manufacturing device B200 has a supply part B210, a coating part B220, a drying part B230, a cooling part B240 and a winding part B250. Ba~Bd represent the conveying rollers of the conveying support body B110.

The supply part B210 has a feeding device (not shown) for feeding out the roll body B201 of the belt-shaped support body B110 wound around the core.

The coating part B220 is a coating device and includes a support roller B221 holding the support B110, a coating head B222 that applies the optical film solution on the support B110 held by the support roller B221, and an upstream side of the coating head B222. The decompression chamber B223 is provided on the side.

The flow rate of the optical film solution discharged from the coating head B222 can be adjusted by a pump (not shown). The flow rate of the optical film solution discharged from the coating head B222 is set to an amount that can stably form a coating layer with a specified film thickness during continuous coating under the conditions of the coating head B222 adjusted in advance.

The decompression chamber B223 is a mechanism for stabilizing beads (retention of the coating liquid) formed between the optical film solution from the coating head B222 and the support B110 during coating, and the degree of decompression can be adjusted. . The decompression chamber B223 is connected to a decompression blower (not shown) to decompress the interior. The decompression chamber B223 is in a state without air leakage, and the gap with the support roller is also narrowly adjusted, so that stable beads of the coating liquid can be formed.

The drying part B230 is a drying device that dries the coating film formed on the surface of the support B110, and has a drying chamber B231, a drying gas inlet B232, and a discharge port B233. The temperature and air volume of the drying air can be appropriately determined according to the type of coating film and the type of support B110. By setting the conditions such as the temperature, air volume, and drying time of the drying air in the drying section B230, the amount of residual solvent in the dried coating film can be adjusted. The amount of residual solvent in a dried coating film can be measured by comparing the unit mass of the dried coating film with the mass of the coating film after sufficient drying.

(amount of residual solvent) After the optical film is obtained by applying the optical film solution, the solvent derived from the solution remains. The amount of residual solvent can be determined by the solvent and coating liquid concentration used, the wind speed blown during drying of the optical film, the drying temperature and time, the conditions of the drying room (external air or internal air circulation), and the back roller during coating Controlled by the heating temperature, etc.

As mentioned above, when drying at a high speed, the film becomes sparse and the surface state can be controlled.

From the viewpoint of the curl balance of the optical film, when the residual solvent amount of the optical film is regarded as S1, it is preferable to satisfy the following formula 2.

Specifically, the residual solvent amount of the optical film is preferably less than 800 ppm, and considering the curl balance of the optical film, it is more preferably 500 to less than 700 ppm. In addition, by selecting a solvent and coating process that allow solvent to remain on the support, the adhesion between the support and the optical film is improved. The residual solvent amount of the support is preferably in the range of 10 to 100 ppm.

The amount of residual solvent in the support and optical film can be measured by headspace gas chromatography. In headspace gas chromatography, the sample is sealed in a container, heated, and while the container is filled with volatile components, the gas in the container is quickly injected into the gas chromatograph, and mass analysis is performed to identify the compound. Quantify the volatile components. In the headspace method, all peaks of volatile components can be observed with a gas chromatograph. At the same time, by using an analysis method that utilizes electromagnetic interaction, volatile substances or monomers can also be quantified with high precision. .

The cooling part B240 cools the temperature of the support B110 having the coating film (optical film) dried by the drying part B230, and adjusts it to an appropriate temperature. The cooling part B240 has a cooling chamber B241, a cooling air inlet B242, and a cooling air outlet B243. The temperature and air volume of the cooling air can be appropriately determined according to the type of coating film and the type of support B110. In addition, when the appropriate cooling temperature can be achieved without providing the cooling part B240, the cooling part B240 may be omitted.

The winding part B250 is a winding device (not shown) for winding the support body B110 on which the optical film is formed to obtain a roll body B251.

[1.4.2] Formation method of adhesive layer The adhesive layer of the present invention is preferably formed as a layer adjacent to the release film. The method of forming the release film will be described later.

The adhesive layer of the present invention can be formed using an adhesive. The adhesive used in the present invention can be prepared by mixing the (meth)acrylic copolymer (P), the cross-linking agent (Q) and other components as necessary by a conventional method. For example, a polymer solution containing the (meth)acrylic copolymer (P) obtained when the polymer is synthesized is blended with the cross-linking agent (Q) and optional other components.

Next, the obtained adhesive is applied to the surface side of the release layer of the release film. Specifically, the obtained adhesive is applied to the surface side of the release layer of the release film.

As the coating method of the adhesive, well-known methods can be used, such as spin coating, knife coating, roller coating, rod coating, blade coating, die coating, gravure coating, etc. A method of coating and drying to achieve a specific thickness.

Conditions for forming the adhesive layer are as follows, for example. The adhesive is applied to the release film. Although it also depends on the type of solvent, it is usually in the range of 50 to 150°C, preferably in the range of 60 to 100°C, and usually in the range of 1 to 10 minutes. Drying is carried out within the range of 2 to 7 minutes to remove the solvent and form a coating film. The thickness of the dry coating film is usually in the range of 1 to less than 10 μm, preferably in the range of 3 to 7 μm.

After forming an adhesive layer on the release film, it is bonded to the optical film. The laminated film thus obtained is usually kept for more than 3 days, preferably within the range of 7 to 10 days, usually within the range of 5 to 60°C, preferably within the range of 15 to 40°C, and usually within the range of 30 to 70% RH. Within the range, it is preferably matured in an environment within the range of 40~70%RH. If cross-linking is performed under the above-mentioned aging conditions, a cross-linked body (network polymer) can be formed efficiently.

[1.4.3] Manufacturing method of release film Various resin films can be used as the base material of the release film of the present invention, but here, an example in which the release film of the present invention is obtained by laminating a release layer using a polyester film as a base material will be described.

As the polyester film, the polyester described in [1.3.1] Release film constituents can be used, and a method in which the molten sheet extruded from the die is cooled and solidified with a cooling roll to obtain an unstretched sheet is preferred. At this time, in order to improve the flatness of the sheet, it is necessary to improve the adhesion between the sheet and the rotating cooling drum, and it is preferable to use an electrostatic application adhesion method and/or a liquid coating adhesion method.

Next, the obtained unstretched sheet is stretched in the biaxial direction. At that time, the aforementioned unstretched sheet is first stretched in one direction by a roller or tenter stretching machine. The extension temperature is usually in the range of 70~120°C, preferably in the range of 80~110°C, and the extension ratio is usually in the range of 2.5~7.0 times, preferably in the range of 3.0~6.0 times. Next, the extension temperature orthogonal to the extension direction of the first segment is usually in the range of 70~170°C, and the extension ratio is usually in the range of 3.0~7.0 times, preferably in the range of 3.5~6.0 times, more preferably Within the range of 5.0~6.0 times. Furthermore, heat treatment is then performed at a temperature in the range of 180 to 270°C under tension or relaxation within 30%, to obtain a biaxially aligned film. In the above-mentioned stretching, a method of extending in one direction in two or more stages may also be used. At that time, it is preferably carried out so that the stretching ratios in both directions finally fall into the above ranges.

In addition, regarding the production of the polyester film in the present invention, the simultaneous biaxial stretching method can also be used. At the same time, the biaxial stretching method is to stretch the aforementioned unstretched sheet in the machine direction and width direction simultaneously in a temperature-controlled state within the range of usually 70 to 120°C, preferably 80 to 110°C. The method for aligning the stretch magnification is that the area magnification is in the range of 4 to 50 times, preferably in the range of 7 to 35 times, and more preferably in the range of 10 to 25 times. Furthermore, heat treatment is then performed at a temperature in the range of 170 to 250°C under tension or under relaxation within 30%, to obtain a stretched alignment film. Regarding the simultaneous biaxial extending device using the above extending method, conventional extending methods such as screw method, scaling method, linear drive method, etc. can be used.

Furthermore, in the above-mentioned stretching step of the polyester film, a so-called coating stretching method (in-line coating) may be applied to treat the film surface. When a coating layer is provided on a polyester film by the coating and stretching method, it can be coated simultaneously with stretching, and the thickness of the coating layer can be reduced according to the stretching ratio, and a suitable film can be produced as a polyester film.

Next, a release layer is formed on the polyester film. The release layer preferably contains a curable polysilicone resin, and the curable polysiloxane resin described in [1.3.1] Release film constituents can be used.

As the coating method, well-known methods can be used, for example, reverse gravure coating, direct gravure coating, roll coating, die coating, rod coating, curtain coating, etc. can be used for coating and drying. Methods.

There are no special restrictions on the hardening conditions. When forming a release layer by off-line coating, it is usually suitable to be within the range of 120~200°C and within the range of 3~40 seconds, and preferably within the range of 100~180°C. And the range of 3 to 40 seconds is used as the target for heat treatment. Furthermore, if necessary, heat treatment and active energy ray irradiation such as ultraviolet irradiation may be used in combination. In addition, as the energy source for hardening by active energy ray irradiation, conventional devices and energy sources can be used.

The coating amount of the release layer (after drying) is usually 0.005~1g/ ^m2 , preferably 0.005~0.5g/ ^m2 , and more preferably 0.01~0.2g/m2 from the perspective of coatability. Within the range of ² . When the coating amount (after drying) is 0.005g/m2 or ^more , the coating properties and stability are good, and a uniform coating film is easily obtained. In addition, when it is 1 g/m ² or less, the coating film adhesion and curability of the release layer itself become good.

Regarding the release film in the present invention, a coating layer such as an antistatic layer or an oligomer precipitation preventing layer may be provided on the film surface where the release layer is not provided. Furthermore, the polyester film constituting the release film may be subjected to surface treatment such as corona treatment and plasma treatment in advance.

≪2 laminated body≫ One embodiment of the laminated body of the present invention is that the laminated film of the present invention and the glass plate are bonded together through the adhesive layer of the present invention. In addition, the present invention is not limited to the glass plate. Instead of the glass plate, a resin such as a thermoplastic resin may be used as the base material. FIG. 3 shows an example of the preferred layer structure of the laminate of the present invention, but is not limited thereto.

FIG. 3 is a cross-sectional view showing the basic structure of the layer structure of the laminated body of the present invention. The laminated body 60 of the present invention is composed of the optical film 1, the adhesive layer 2 and the glass plate 11.

The laminated system of the present invention is obtained by bonding the laminated film of the present invention and the glass plate through an adhesive layer. By using the laminated film of the present invention, the laminated system is less likely to be damaged and optical unevenness is less likely to occur even if it is repeatedly folded. In addition, the glass plate itself is not easily damaged.

＜Glass plate＞ The thickness of the glass plate of the present invention is preferably 150 μm or less from the viewpoint of flexibility. Moreover, it is more preferably 120 μm or less, still more preferably 100 μm or less, and particularly preferably 80 μm or less. The lower limit of the thickness is not particularly limited, but from the viewpoint of handleability or breakability in a production line or post-processing step, it is preferably 5 μm or more, more preferably 10 μm or more, and particularly preferably 15 μm or more. The best range is 25~50μm.

The material of the glass plate is not particularly limited, as long as it is made of glass, it can be suitably used. Examples include soda-lime glass, borosilicate glass, alkali-free glass, alkali glass, and the like. Among them, alkali-free glass is preferred from the viewpoints of thermal expansion resistance, smoothness, durability, dimensional stability, cost, and the like.

In addition, the glass plate can be formed by a well-known forming method such as a float method or a down-draw method. From the viewpoint that the surface of the glass plate becomes an unground flame-polished surface and becomes extremely smooth, it is preferably formed by the overflow down-drawing method. As the glass plate described above, commercially available ones can be used, and "D263" and "Xensagtion Flex" made by SCHOTT Co., Ltd., "G-Leaf" and "Dynorex UTG" made by Nippon Electric Glass Co., Ltd. and "Dynorex UTG" made by CORNING Co., Ltd. can be used. Glass films such as Gorilla glass" and "Dragon Trail Pro" made by AGC.

The surface of the glass plate can be appropriately surface treated in advance. Examples of the surface treatment include coupling agent treatment such as silane coupling agent and titanium coupling agent, chemical conversion treatment such as acid treatment, alkali treatment, ozone treatment, and ion treatment, plasma treatment, glow discharge treatment, and arc discharge treatment. And various surface treatments such as discharge treatment such as corona treatment, ultraviolet treatment, X-ray treatment, gamma ray treatment, laser treatment, electromagnetic wave irradiation treatment, and other flame treatments.

Moreover, as mentioned above, the optical film of the present invention is bonded to a glass plate through an adhesive layer. The optical film of the present invention is made of resin, and when it is bonded to a glass plate made of materials with different shrinkage rates, stress is generated in the adhesive layer. It is believed that due to this stress, the adhesive layer will undergo birefringence, causing the polarization state to become disordered, and there is a possibility of "uneven phenomena" occurring.

However, in the case where the above-mentioned uneven phenomenon occurs, by using an adhesive that exhibits the inherent birefringence value of the adhesive layer, it becomes possible to offset the photoelasticity of the glass plate caused by the expansion and contraction stress of the resin-made optical film. composition, and it is believed that the "uneven phenomenon" has been improved.

Furthermore, it is more preferable to have a structure that offsets both the photoelasticity of the film and the photoelasticity of the glass plate caused by the expansion and contraction stress of the resin optical film.

As a method of adjusting the birefringence value inherent in the adhesive layer, for example, it can be easily obtained by appropriately changing the usage amount of the hardener or cross-linking agent, the composition of the forming material such as the monomer, and other additives if necessary. The adhesive that forms the adhesive layer of the present invention is not particularly limited, and there are no particular limitations on the type or composition of the monomer used, the type or usage amount of the hardener, and the manufacturing method.

As an example of a method for adjusting the inherent birefringence value of an adhesive to an appropriate value, it is possible to appropriately blend an acrylic resin with a low glass transition temperature (Tg) and butyl acrylate (BA) with negative alignment birefringence and Phenoxy acrylate (PHEA), which has positive birefringence, is used to adjust the birefringence of the resulting copolymer.

≪3 Polarizing plate≫ The polarizing plate of the present invention is characterized by using the laminated film of the present invention. FIG. 4 shows an example of the preferred layer structure of the polarizing plate of the present invention, but is not limited thereto.

FIG. 4A is a cross-sectional view showing the basic structure of the layer structure of the polarizing plate 70 of the present invention. The polarizing plate 70 of the present invention is composed of an optical film 1, an adhesive layer 2, a release film 3 and a polarizing sub-layer 21.

Furthermore, as shown in FIG. 4B , a liquid crystal alignment layer 22 can be disposed between the polarizing sub-layer 21 and the optical film 1 , and on the opposite side, a retardation film 23 can be disposed through the adhesive layer 24 . Furthermore, the retardation film 23 may be in a form in which the release film 3 on the adhesive layer 2 is peeled off and then bonded to the retardation film 23 (not shown).

4C is a cross-sectional view showing the basic structure of the layer structure of the polarizing plate 80 with a glass plate of the present invention. After peeling off the release film 3, the glass plate 11 is bonded together, and the barrier layer 27 is disposed instead of the retardation film 23. Furthermore, the glass plate 11 can be the substrate glass of a liquid crystal display, or it can be ultra-thin film glass that reaches the outermost layer.

The thickness of the polarizing plate of the present invention is preferably in the range of 10 to 100 μm, more preferably in the range of 30 to 80 μm, and particularly preferably in the range of 40 to 70 μm from the viewpoint of the flexibility or visibility of the display device. within the range.

[3.1]Polarizing sublayer The polarizing plate of the present invention can be obtained by further laminating a polarizing sub-layer on the laminated film or laminated body of the present invention. Furthermore, the so-called "polarized photon" refers to an element that only passes through the polarization plane of light in a certain direction. An example of the preferred structure of the polarizing sub-layer of the present invention is shown below, but is not limited thereto.

The polarizer layer of the present invention is shown in Figure 5A. It can be the polarizer composed of iodine and polyvinyl alcohol (PVA) that has been widely used in the past. However, from the industrial point of view of improving the durability against the folding action, The polarizer of the entire film is preferred, and therefore the coating-type polarizer in which a dichroic organic dye is added to the liquid crystal layer as shown in FIG. 5B is preferred.

The polarizing sub-layer 21 shown in FIG. 5A can be formed by adsorbing and aligning the dichroic pigment to a uniaxially stretched resin film. As dichroic pigments, they are generally iodine and organic dichroic pigments. The resin used in the resin film may be a hydrophobic resin or a hydrophilic resin, but a hydrophilic resin is preferred. In addition, the resin film can also be stretched.

Examples of hydrophilic resins are polyvinyl alcohol-based resins, polyvinyl acetate resins, and ethylene-vinyl acetate copolymer resins (EVA) resins. Examples of hydrophobic resins are polyamide resins and polyester-based resins.

The polarizing sub-layer can be treated with boric acid after dyeing. When the resin layer of the polarizing sub-layer is made of a hydrophilic resin such as polyvinyl alcohol-based resin, more moisture enters and exits from the outside than a hydrophobic resin. This is considered to be a cause of pigment loss or optical resin in a hot and humid environment. The reason why the film peels off from the polarizing sub-layer in the end face is that such peeling or peeling of the pigment can be suppressed by the composition of the present invention.

The polarization sub-layer preferably has a polarization sub-protection layer 28 through the adhesive layer 24 . As the polarizer protective layer, commercially available cellulose chelate films (for example, Konica-Minolta KC8UX, KC5UX, KC4UX, KC8UCR3, KC4SR, KC4BR, KC4CR, KC4DR, KC4FR, KC4KR, KC8UY, KC6UY, KC4UY, KC4UE, KC8UE, KC8UY-HA, KC2UA, KC4UA, KC6UA, KC2UAH, KC4UAH, KC6UAH, the above are manufactured by Konica Minolta Advanced Layer Co., Ltd.), polyester film (such as polyethylene terephthalate film, etc.), cyclic olefin Resin film, acrylic resin film, etc.

The thickness of the film used for the polarizer protective layer is not particularly limited, but it is preferably in the range of 1 to 100 μm, more preferably in the range of 3 to 40 μm, and particularly preferably in the range of 5 to 20 μm.

In addition, the polarizing sublayer 21 shown in FIG. 5B can be formed by curing a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound and a dichroic dye described below. Since the polarizing sub-layer can be made thinner, it is preferable from the viewpoint of obtaining sufficient bending resistance. Such a structure is sufficient depending on the application. However, in order to further improve the scratch and high-temperature and high-humidity durability of the polarizing sub-layer, it is preferable to coat the polarizing sub-layer 21 with the barrier layer 27 or to provide it more closely to the optical film 1. Protective layer (not shown in Figure 5B).

[3.1.1]Polymerizable liquid crystal compound The polymerizable liquid crystal compound (hereinafter also referred to as the "polymerizable liquid crystal compound (A')") contained in the polymerizable liquid crystal composition (hereinafter also referred to as the "polymerizable liquid crystal composition (A')") used for the formation of the polarizing sub-layer )") is a liquid crystal compound having at least one polymerizable group.

Here, the term "polymerizable group" refers to a group that can participate in the polymerization reaction through active radicals or acids generated from the polymerization initiator. Examples of the polymerizable group possessed by the polymerizable liquid crystal compound (A′) include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloxy, and methane. Acryloxy group, ethylene oxide group, oxetanyl group, etc. Among them, a radically polymerizable group is preferred, an acryloxy group, a methacryloyloxy group, a vinyl group, and an vinyloxy group are more preferred, and an acryloyloxy group or a methacryloyloxy group is particularly preferred.

The polymerizable liquid crystal compound (A') is preferably a compound showing smectic liquid crystallinity. By using a polymerizable liquid crystal compound that exhibits smectic liquid crystallinity, polarized photons with a high degree of alignment order can be formed. The liquid crystal state represented by the polymerizable liquid crystal compound (A') is a smectic phase (smectic liquid crystal state), and from the viewpoint of achieving a higher degree of alignment order, a higher-order smectic phase (high-order smectic phase) is more preferred. liquid crystal state).

Here, the so-called high-order smectic phase means smectic B phase, smectic D phase, smectic E phase, smectic F phase, smectic G phase, smectic H phase, smectic I phase, and smectic J phase. phase, the smectic K phase and the smectic L phase, among them, the smectic B phase, the smectic F phase and the smectic I phase are more preferred. The liquid crystallinity may be a thermotropic liquid crystal or a lyotropic liquid crystal, but thermotropic liquid crystal is preferred since a dense film thickness can be controlled. In addition, the polymerizable liquid crystal compound (A') may be a monomer, an oligomer obtained by polymerizing a polymerizable group, or a polymer.

The polymerizable liquid crystal compound (A') is not particularly limited as long as it has at least one polymerizable group. Well-known polymerizable liquid crystal compounds can be used, but a compound showing smectic liquid crystal properties is preferred. Examples of such a polymerizable liquid crystal compound include a compound represented by the following formula (A'1) (hereinafter also referred to as "polymerizable liquid crystal compound (A'1)").

[In formula (A'1), X ₁ and X ₂ independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the divalent aromatic group or divalent alicyclic hydrocarbon group The hydrogen atoms contained in the hydrocarbon group can be substituted with halogen atoms, alkyl groups with 1 to 4 carbon atoms, fluoroalkyl groups with 1 to 4 carbon atoms, alkoxy groups with 1 to 4 carbon atoms, cyano groups or nitro groups, forming the The carbon atom of the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom, or a nitrogen atom. However, at least one of X ₁ and X ₂ is an optionally substituted 1,4-phenylene group or an optionally substituted cyclohexane-1,4-diyl group.

Y ₁ is a single bond or a bivalent linking group.

When n is 1 to 3, and n is 2 or more, the plural X _1's may be the same or different from each other. X ₂ may be the same as or different from any or all of the plural X _1s . In addition, when n is 2 or more, the plural Y _1's may be the same as each other or may be different. From the viewpoint of liquid crystallinity, n is preferably 2 or more.

U ₁ represents a hydrogen atom or a polymerizable group.

U ₂ represents a polymerizable group.

W ₁ and W ₂ are independently single bonds or divalent linking groups.

V ₁ and V ₂ independently represent an alkanediyl group having 1 to 20 carbon atoms that may have a substituent, and -CH ₂ - constituting the alkanediyl group may be substituted with -O-, -CO-, -S- or NH-. ]

In the polymerizable liquid crystal compound (A'1), X ₁ and X ₂ are preferably independently a 1,4-phenylene group which may have a substituent or a cyclohexane-1,4-diyl group which may have a substituent. , at least one of X _{1 and} 1,4-diradical. Examples of substituents optionally possessed by the optionally substituted 1,4-phenylene group or the optionally substituted cyclohexane-1,4-diyl group include methyl, ethyl, butyl, and the like. Halogen atoms such as alkyl groups with 1 to 4 carbon atoms, cyano groups, chlorine atoms, fluorine atoms, etc. No substitution is preferred.

Moreover, in the formula (A'1), the polymerizable liquid crystal compound (A'1) is: [In the formula, X ₁ , Y ₁ , X ₂ and n each represent the same definition as above. ] (hereinafter also referred to as "partial structure (A'1-1)") is preferably an asymmetric structure in that it can easily exhibit smectic liquid crystallinity.

Examples of the polymerizable liquid crystal compound (A'1) in which the partial structure (A'1-1) is an asymmetric structure include polymerizable liquid crystal compounds in which n is 1 and X ₁ and X ₂ are mutually different structures. (A'1).

Alternatively, n is 2, two Y _1's are compounds with the same structure, two X _1's are the same structure as each other, and one X ₂ is a polymer of structures different from these two X _1's . In the liquid crystal compound (A'1), the _X1 bonded to _W1 among the two _X1s has a different structure from the other _X1 and _X2 , and the other _X1 and _X2 are a polymerization of the same structure. Sexual liquid crystal compound (A'1).

Examples include polymerizable liquid crystals in which n is 3, three Y _1's have the same structure as each other, and any one of three X _1's and one X ₂ has a different structure from the other three. Compound (A'1).

Y ₁ is preferably -CH ₂ CH ₂ -, -CH ₂ O-, -CH ₂ CH ₂ O-, -COO-, -OCOO-, single bond, -N=N-, -CRa=CRb-, - C≡C-, -CRa=N- or CO-NRa-. Ra and Rb independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

Y ₁ is more preferably -CH ₂ CH ₂ -, -COO- or a single bond. When Y ₁ is a plural number, Y ₁ bonded to X ₂ is more preferably -CH ₂ CH ₂ - or CH ₂ O-. When X ₁ and X ₂ all have the same structure, it is preferable that there are two or more Y ₁ with mutually different bonding methods. When a plurality of Y _1's with mutually different bonding methods are present, the structure becomes asymmetric and tends to exhibit smectic liquid crystallinity.

U ₂ is a polymerizable group. U ₁ is a hydrogen atom or a polymerizable group, preferably a polymerizable group. U ₁ and U ₂ are preferably both polymerizable groups, and more preferably both are radically polymerizable groups. Examples of the polymerizable group include the same groups as those exemplified previously as the polymerizable group possessed by the polymerizable liquid crystal compound (A′). The polymerizable group represented by U ₁ and the polymerizable group represented by U ₂ may be different from each other, but are preferably the same type of group. In addition, the polymerizable group may be in a polymerized state or an unpolymerized state, but is preferably in an unpolymerized state.

Examples of the alkanediyl groups represented by V ₁ and V ₂ include methylene, vinyl, propane-1,3-diyl, butane-1,3-diyl, and butane-1,4-diyl. base, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, decane-1,10-diyl base, tetradecane-1,14-diyl and eicosane-1,20-diyl, etc. V ₁ and V ₂ are preferably an alkylenediyl group having a carbon number of 2 to 12, more preferably an alkanediyl group having a carbon number of 6 to 12.

Examples of substituents that the alkylenediyl group may have include a cyano group, a halogen atom, and the like. However, the alkylenediyl group is preferably unsubstituted, and more preferably an unsubstituted linear alkylenediyl group.

W ₁ and W ₂ are independently preferably a single bond, -O-, -S-, -COO- or OCOO-, more preferably a single bond or -O-.

The polymerizable liquid crystal compound (A') is not particularly limited as long as it has at least one polymerizable group. Well-known polymerizable liquid crystal compounds can be used, but those showing smectic liquid crystal properties are preferred. . As a structure that easily exhibits smectic liquid crystallinity, a molecular structure having asymmetry in the molecular structure is preferred, and specific examples include partial structures having the following (A'-a) to (A'-i) A polymeric liquid crystal compound. From the viewpoint of easily exhibiting high-order smectic liquid crystallinity, those having a partial structure of (A'-a), (A'-b) or (A'-c) are more preferred. Incidentally, in the following (A’-a) to (A’-i), * represents a bond (single bond).

Specific examples of the polymerizable liquid crystal compound (A') include compounds represented by the following (A'-1) to (A'-25). When the polymerizable liquid crystal compound (A') has a cyclohexane-1,4-diyl group, the cyclohexane-1,4-diyl group is preferably a trans form.

Among these, it is preferable to be selected from (A'-2), (A'-3), (A'-4), (A'-5), (A'-6), (A'- 7), (A'-8), (A'-13), (A'-14), (A'-15), (A'-16) and (A'-17). At least 1 species in the group. As the polymerizable liquid crystal compound (A'), one type may be used alone, or two or more types may be used in combination.

The polymerizable liquid crystal compound (A') can be produced by a well-known method described in, for example, Lub et al., Reel. Trav. Chim. Pays-Bas, 115, 321-328 (1996) or Japanese Invention Patent No. 4719156.

In the present invention, the polymerizable liquid crystal composition (A') may also contain polymerizable liquid crystal compounds other than the polymerizable liquid crystal compound (A'). From the viewpoint of obtaining a polarizing film with a high degree of alignment order, relative to the polymerizable liquid crystal composition (A'), The total mass of all polymerizable liquid crystal compounds contained in the liquid crystal composition (A'), the proportion of the polymerizable liquid crystal compound (A') is preferably 51 mass % or more, more preferably 70 mass % or more, especially 90 mass % %above.

Moreover, when the polymerizable liquid crystal composition (A') contains two or more types of polymerizable liquid crystal compounds (A'), at least one of them may be a polymerizable liquid crystal compound (A'1), or all of them may be polymerizable liquid crystal compounds (A'1). Liquid crystal compound (A'1). By combining a plurality of polymerizable liquid crystal compounds, liquid crystallinity may be temporarily maintained even at a temperature below the liquid crystal-crystal phase transition temperature.

The content of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition (A') is preferably in the range of 40 to 99.9% by mass, more preferably 60 to 99.9% by mass relative to the solid content of the polymerizable liquid crystal composition (A'). Within the range of 99 mass %, particularly preferably within the range of 70 to 99 mass %. When the content of the polymerizable liquid crystal compound is within the above range, the alignment of the polymerizable liquid crystal compound tends to become high. In addition, in this specification, the solid content of the polymerizable liquid crystal composition (A') refers to the total amount of components after removing the solvent from the polymerizable liquid crystal composition (A').

[3.1.2]Dichroic pigments The dichroic dye contained in the polymerizable liquid crystal composition (A') used for forming the polarizing sub-layer means a dye having a property in which the absorbance in the long axis direction of the molecule is different from the absorbance in the short axis direction. The dichroic dye is not particularly limited as long as it has the above properties, and may be a dye or a pigment. Furthermore, two or more dyes or pigments may be used in combination, or a dye and a pigment may be used in combination.

As the dichroic dye, an organic dichroic dye (also called "organic dichroic dye") is preferred, and one having a maximum absorption wavelength (λ _MAX ) in the range of 300 to 700 nm is more preferred. Examples of such dichroic dyes include acridine dyes, trichrome dyes, cyanine dyes, naphthalene dyes, azo dyes, and anthraquinone dyes.

Examples of azo dyes include monoazo dyes, disazo dyes, trisazo dyes, tetrasazo dyes, stilbene azo dyes, etc. Preferred are disazo dyes and trisazo dyes, for example Examples include compounds represented by formula (I) (hereinafter also referred to as "compound (I)").

[In formula (I), K ₁ and K ₃ independently represent a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or a monovalent heterocyclic group which may have a substituent; K ₂ represents an optional substituent. p-phenylene group, naphthalene-1,4-diyl group which may have a substituent or a divalent heterocyclic group which may have a substituent group; p represents an integer from 1 to 4; when p is an integer of 2 or more, the plural K ₂ can be the same or different from each other; in the range where absorption is shown in the visible light region, the -N=N- bond can be replaced by -C=C-, -COO-, -NHCO-, -N=CH- bond. ]

Examples of the monovalent heterocyclic group include a group obtained by removing one hydrogen atom from a heterocyclic compound such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, 㗁azole, benzo㗁azole, and the like. Examples of the divalent heterocyclic group include a group obtained by removing two hydrogen atoms from the aforementioned heterocyclic compound.

As substituents optionally possessed by the phenyl group, naphthyl group and monovalent heterocyclic group in K ₁ and K ₃ and the p-phenylene group, naphthalene-1,4-diyl group and divalent heterocyclic group in K ₂ , examples include alkyl groups with 1 to 4 carbon atoms; alkoxy groups with 1 to 4 carbon atoms such as methoxy, ethoxy, butoxy, etc.; fluorinated fluorinated groups with 1 to 4 carbon atoms such as trifluoromethyl. Alkyl group; cyano group; nitro group; halogen atom; substituted or unsubstituted amine group such as amino group, diethylamino group, pyrrolidinyl group (the so-called substituted amine group means having 1 or 2 carbon atoms The amino group of an alkyl group with 1 to 6 carbon atoms, or two substituted alkyl groups bonded to each other to form an amine group of an alkyldiyl group with 2 to 8 carbon atoms; the unsubstituted amino group is -NH ₂ ), etc.

Among the compounds (I), compounds represented by any one of the following formulas (I-1) to (I-8) are preferred.

[In the formulas (I-1) to (I-8), B ¹ to B ³⁰ independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, and a nitrogen group. group, a substituted or unsubstituted amine group (the definitions of a substituted amine group and an unsubstituted amine group are as mentioned above), a chlorine atom or a trifluoromethyl group.

n1~n4 independently represent integers from 0 to 3.

When n1 is 2 or more, the plural B ^2s may be the same or different from each other. When n2 is 2 or more, the plural B ^6s may be the same or different from each other. When n3 is 2 or more, the plural B ^9s may be the same or different from each other. n4 is When 2 or more, the plural B ¹⁴ may be the same or different from each other. ] As the anthraquinone dye, a compound represented by formula (I-9) is preferred.

[In formula (I-9), R ¹ ~ R ⁸ independently represent a hydrogen atom, -R ^x , -NH ₂ , -NHR ^x , -NR ^x ₂ , -SR ^x or a halogen atom; R ^x represents the carbon number Alkyl group with 1 to 4 carbon atoms or aryl group with 6 to 12 carbon atoms. ]

As the above-mentioned ethazolidone dye, a compound represented by formula (I-10) is preferred.

[In formula (I-10), R ⁹ ~ R ¹⁵ independently represent a hydrogen atom, -R ^x , -NH ₂ , -NHR ^x , -NR ^x ₂ , -SR ^x or a halogen atom; R ^x represents the carbon number Alkyl group with 1 to 4 carbon atoms or aryl group with 6 to 12 carbon atoms. ]

As the acridine dye, a compound represented by formula (I-11) is preferred.

[In formula (I-11), R ¹⁶ ~ R ²³ independently represent a hydrogen atom, -R ^x , -NH ₂ , -NHR ^x , -NR ^x ₂ , -SR ^x or a halogen atom; R ^x represents the carbon number Alkyl group with 1 to 4 carbon atoms or aryl group with 6 to 12 carbon atoms. ]

In Formula (I-9), Formula (I-10) and Formula (I-11), examples of the alkyl group having 1 to 6 carbon atoms in ^Rx include methyl, ethyl, propyl, butyl, Examples of the aryl group having 6 to 12 carbon atoms such as pentyl group and hexyl group include phenyl group, toluyl group, xylyl group, naphthyl group, and the like.

As the cyanine pigment, the compound represented by formula (I-12) and the compound represented by formula (I-13) are preferred.

[In formula (I-12), D ¹ and D ² independently represent a base represented by any one of formula (I-12a) to formula (I-12d); n5 represents an integer of 1 to 3. ]

[In formula (I-13), D ³ and D ⁴ independently represent a base represented by any one of formula (I-13a) to formula (I-13h); n6 represents an integer of 1 to 3. ]

Among these dichroic dyes, azo dyes are suitable for producing polarizers with excellent polarization properties due to their high linearity. Therefore, the dichroic dye contained in the polymerizable liquid crystal composition forming the polarizer layer is preferably: Azo pigments.

The weight average molecular weight of the dichroic pigment is usually in the range of 300 to 2000, preferably in the range of 400 to 1000.

The content of the dichroic dye in the polymerizable liquid crystal composition (A') can be appropriately determined depending on the type of dichroic dye used, etc., but it is preferably 0.1 to 50 parts by mass based on 100 parts by mass of the polymerizable liquid crystal compound. Within the range of parts by mass, more preferably within the range of 0.1 to 20 parts by mass, particularly preferably within the range of 0.1 to 12 parts by mass. If the content of the dichroic dye is within the above range, the alignment of the polymerizable liquid crystal compound is less likely to be disrupted, and a polarizing sublayer with a high degree of alignment order can be obtained.

[3.1.3]Additives The polymerizable liquid crystal composition (A') may further contain additives other than the polymerizable liquid crystal compound and the dichroic dye, preferably more than 0% and 20% by mass relative to the solid content of the polymerizable liquid crystal composition (A') or less, more preferably more than 0% and 10 mass% or less. Examples of additives include colorants such as polymerization initiators, photosensitizers, leveling agents, antioxidants, release agents, stabilizers, bluing agents, flame retardants, and lubricants.

＜Polymerization initiator＞ The polymerization initiator is a compound that can initiate the polymerization reaction of the polymerizable liquid crystal compound. Since the polymerization reaction can be initiated under lower temperature conditions, a photopolymerization initiator is preferred. Specific examples thereof include photopolymerization initiators that can generate active radicals or acids by the action of light, and among these, photopolymerization initiators that can generate free radicals by the action of light are preferred. The polymerization initiator can be used alone or in combination of two or more kinds.

As the photopolymerization initiator, a well-known photopolymerization initiator can be used. For example, the photopolymerization initiator that generates active radicals includes a self-cleavage type photopolymerization initiator and a hydrogen extraction type photopolymerization initiator. Polymerization initiator.

Examples of the self-cleaving type photopolymerization initiator include self-cleaving benzoin-based compounds, acetophenone-based compounds, hydroxyacetophenone-based compounds, α-aminoacetophenone-based compounds, and oximes Ester compounds, acylphosphine oxide compounds, azo compounds, etc. Examples of the hydrogen extraction type photopolymerization initiator include hydrogen extraction type benzophenone-based compounds, benzoin ether-based compounds, benzyl ketal-based compounds, and dibenzocycloheptanone-based compounds. , Anthraquinone series compounds, xanthone series compounds, thioxanthone series compounds, haloacetophenone series compounds, dialkoxyacetophenone series compounds, halobisimidazole series compounds, halotribasic compounds, Three 𠯤 series compounds, etc.

As a photopolymerization initiator that generates acid, iodonium salt, sulfonium salt, etc. can be used.

Among them, from the viewpoint of preventing the dissolution of the pigment, a low-temperature reaction is preferable. From the viewpoint of low-temperature reaction efficiency, a self-cleaving type photopolymerization initiator is preferable, and an acetophenone compound is particularly preferable. , hydroxyacetophenone compounds, α-aminoacetophenone compounds, and oxime ester compounds.

Specific examples of the photopolymerization initiator include the following.

Benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzoin isobutyl ether; 2-Hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethane-1-one, 2-hydroxy-2-methyl -1-[4-(2-hydroxyethoxy)phenyl]propan-1-one, 1-hydroxycyclohexylphenylketone and 2-hydroxy-2-methyl-1-[4-(1-methyl Hydroxyacetophenone compounds such as oligomers of vinyl)phenyl]propane-1-one; 2-Methyl-2-morpholino-1-(4-methylthiophenyl)propan-1-one, 2-dimethylamino-2-benzyl-1-(4-morpholinobenzene α-aminoacetophenone compounds such as butane-1-one;

1,2-octanedione, 1-[4-(phenylthio)-,2-(O-benzoyl oxime)], ethanone, 1-[9-ethyl-6-(2-methyl oxime ester compounds such as (benzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyl oxime); 2,4,6-Trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and other acylphosphine oxide compounds ;

Benzophenone, o-benzoyl benzoic acid methyl ester, 4-phenyl benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4, 4'-Tetrakis(tert-butylperoxycarbonyl)benzophenone and 2,4,6-trimethylbenzophenone and other benzophenone compounds;

Dialkoxyacetophenone compounds such as diethoxyacetophenone; 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-trichloromethyl, 2,4-bis(trichloromethyl)-6-(4- Methoxynaphthyl)-1,3,5-trisulfate, 2,4-bis(trichloromethyl)-6-(4-methoxystyryl)-1,3,5-trisulfate, 2,4-bis(trichloromethyl)-6-[2-(5-methylfuran-2-yl)vinyl]-1,3,5-trichloromethyl, 2,4-bis(trichloromethyl base)-6-[2-(furan-2-yl)vinyl]-1,3,5-triethyl, 2,4-bis(trichloromethyl)-6-[2-(4-diethyl) methylamino-2-methylphenyl)vinyl]-1,3,5-tritrimethoxy and 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxy Phenyl)vinyl]-1,3,5-trixamethonium series compounds. The photopolymerization initiator may be appropriately selected from among the above-mentioned photopolymerization initiators in relation to the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition (A).

In addition, commercially available products can be used as the photopolymerization initiator. Examples include "lrgacure (registered trademark) 907, 184, 651, 819, 250, 369, 379, 127 manufactured by BASF" , 754, OXE01, OXE02 and OXE03"; "Omnirad (registered trademark) BCIM, Esacure (registered trademark) 1001M, Esacure (registered trademark) KIP160" manufactured by IDM Resins B.V.; "Seikuol (registered trademark) manufactured by Seiko Chemical Co., Ltd. Trademarks) BZ, Z and BEE"; "kayacure (registered trademark) BP100 and UVI-6992" made by DOW CHEMICAL Co., Ltd.; "Adeka Optomer SP-152, N-1717, N-1919, SP-170, Adkarkls NCI-831 and Adkarkls NCI-930"; "TAZ-A and TAZ-PP" manufactured by SIBERHEGNER Co., Ltd.; "TAZ-104" manufactured by Sanwa Chemical Co., Ltd., etc.

The content of the polymerization initiator is preferably in the range of 1 to 10 parts by mass, more preferably in the range of 1 to 8 parts by mass, and particularly preferably 2 to 8 parts by mass relative to 100 parts by mass of the polymerizable liquid crystal compound. Within the range, the best range is 4 to 8 parts by mass. If the content of the polymerization initiator is within the above upper and lower limits, the polymerization reaction of the polymerizable liquid crystal compound can be carried out without significantly disrupting the alignment of the polymerizable liquid crystal compound.

In addition, the polymerization rate of the polymerizable liquid crystal compound is preferably 60% or more, more preferably 65% or more, and particularly preferably 70% or more, from the viewpoint of production line contamination or operation during production.

＜Photosensitizer＞ The photosensitizer can further promote the polymerization reaction of the polymerizable liquid crystal compound. Examples of the photosensitizer include xanthone-based compounds such as xanthone and thioxanthone (for example, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, etc.); anthracene, Anthracene compounds such as alkoxy anthracene (such as dibutoxy anthracene, etc.); phenanthrene and rubrene, etc. The photosensitizer can be used individually or in combination of 2 or more types.

When the polymerizable liquid crystal composition (A') contains a photosensitizer, its content may be appropriately determined according to the type and amount of the polymerization initiator and the polymerizable liquid crystal compound. However, relative to 100 parts by mass of the polymerizable liquid crystal compound , preferably in the range of 0.1 to 30 parts by mass, more preferably in the range of 0.5 to 10 parts by mass, especially preferably in the range of 0.5 to 8 parts by mass.

＜Leveling agent＞ The leveling agent adjusts the fluidity of the polymerizable liquid crystal composition and has the function of making the coating film obtained by applying the polymerizable liquid crystal composition flatter. Specific examples thereof include surfactants. The leveling agent in the polymerizable liquid crystal composition (A') is preferably selected from a leveling agent containing a polyacrylate compound as a main component and a leveling agent containing a fluorine atom-containing compound as a main component. At least 1 species in the group. Leveling agents can be used alone or in combination of two or more.

Examples of leveling agents containing a polyacrylate compound as a main component include "BYK-350, BYK-352, BYK-353, BYK-354, BYK-355, BYK-358N, BYK manufactured by BYK-Chemie" -361N, BYK-380, BYK-381 and BYK-392".

Examples of leveling agents containing a compound containing a fluorine atom as a main component include "Megafac (registered trademark) R-08, R-30, R-90, F-410, and F-411 manufactured by DIC Co., Ltd." , F-443, F-445, F-470, F-471, F-477, F-479, F-482 and F-483"; "Surflon (registered trademark) S- manufactured by AGC SEMI Chemical Co., Ltd. 381, S-382, S-383, S-393, SC-101, SC-105, KH-40 and SA-100"; "E1830 and E5844" manufactured by Daikin Fine Chemicals Research Institute; Mitsubishi Materials Electronics "Eftop (registered trademark) EF301, Eftop (registered trademark) EF303, Eftop (registered trademark) EF351 and Eftop (registered trademark) EF352" manufactured by Chemical Industry Co., Ltd.

When the polymerizable liquid crystal composition (A') contains a leveling agent, its content is preferably in the range of 0.05 to 5 parts by mass, and more preferably in the range of 0.05 to 3 parts by mass relative to 100 parts by mass of the polymerizable liquid crystal compound. . If the content of the leveling agent is within the aforementioned range, the polymerizable liquid crystal compound will be easily aligned horizontally, unevenness will be less likely to occur, and a smoother polarizing sublayer will tend to be obtained.

[3.1.4] Formation method In the polarizing plate of the present invention, the polarized photons are preferably those with high alignment order. Polarized photons with a high degree of alignment order obtain a Bragg peak derived from a high-order structure of a hexagonal phase or a crystal phase in X-ray diffraction measurement.

The so-called Bragg peak refers to the peak of the periodic structure derived from molecular alignment. Therefore, it is preferable that the polarized photons constituting the polarizing plate of the present invention exhibit a Bragg peak in X-ray diffraction measurement. That is, among the polarized photons constituting the polarizing plate of the present invention, the polymerizable liquid crystal compound or its polymer is preferably aligned so that the polarized photons exhibit a Bragg peak in X-ray diffraction measurement, and more preferably, it absorbs light. The molecules of the polymerizable liquid crystal compound are aligned in the direction called "horizontal alignment".

In the present invention, polarized photons with a molecular alignment plane period interval in the range of 3.0 to 6.0 Å are preferred. A high degree of alignment order such as a Bragg peak can be achieved by controlling the type of polymerizable liquid crystal compound used, the type or amount of the dichroic dye, the type or amount of the polymerization initiator, and the like.

＜Formation method of polarizing sub-layer＞ In the present invention, the thickness of the polarizing sub-layer can be appropriately selected according to the display device suitable for it. The film is preferably in the range of 0.1~5 μm, more preferably in the range of 0.3~4 μm, and particularly preferably in the range of 0.5~3 μm. . If the thickness is thinner than this range, the required light absorption may not be obtained. If the thickness is thicker than this range, the alignment control force of the liquid crystal alignment layer is reduced, and alignment defects tend to easily occur.

In addition, the polarizing sub-layer is laminated on the optical film as the base material through the liquid crystal alignment layer, which is preferable from the viewpoint of improving the liquid crystal alignment degree. As the liquid crystal alignment layer, an optical liquid crystal alignment layer is preferred from the viewpoints of the accuracy and quality of the alignment angle and the water resistance and bendability of the polarizing plate containing the liquid crystal alignment layer. When a liquid crystal alignment layer is included, the thickness of the liquid crystal alignment layer is preferably in the range of 10~5000nm, more preferably in the range of 10~1000nm.

The polarizing plate of the present invention can be produced by forming a coating film of the polymerizable liquid crystal composition (A′) containing a polymerizable liquid crystal compound having a polymerizable group and a dichroic dye, and removing the solvent from the coating film, Then, the temperature is raised to a temperature above which the polymerizable liquid crystal compound is phase-transferred to the liquid phase, and then the temperature is lowered to phase-transfer the polymerizable liquid crystal compound to the smectic phase. The smectic phase is maintained, and the polymerizable liquid crystal compound is polymerized to obtain polarized light. sub-layer (hereinafter also referred to as the "polarizing sub-layer forming step").

In the step of forming the polarizing sub-layer, the coating film of the polymerizable liquid crystal composition (A') can be formed by coating the polymerizable liquid crystal composition directly on the optical film as the base material or via a liquid crystal alignment layer to be described later. Proceed with object (A').

As the base material, the optical film of the present invention can be used, and the polarizing sub-layer can be directly laminated. Alternatively, a film (support) different from the optical film of the present invention may be used as a base material to form a polarizing sub-laminated film, and then be laminated to the optical film of the present invention through an adhesive layer.

Generally speaking, since the viscosity of compounds showing smectic liquid crystallinity is high, from the viewpoint of improving the coating properties of the polymerizable liquid crystal composition (A') and making it easier to form the polarizing sub-layer, the polymerizable liquid crystal composition (A') can be A solvent is added to the liquid crystal composition (A') to adjust the viscosity (hereinafter, a composition in which a solvent is added to a polymerizable liquid crystal composition will also be referred to as a "polarizing sublayer forming composition").

The solvent used in the composition for forming the polarizing sub-layer can be appropriately selected according to the solubility of the polymerizable liquid crystal compound and dichroic dye used. Specific examples thereof include alcohol solvents such as water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellulosine, butyl cellulosine, propylene glycol monomethyl ether, ethyl acetate, Butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, ethyl lactate and other ester solvents, acetone, methyl ethyl ketone, cyclopentanone, cyclohexane Ketone solvents such as ketone, methyl amyl ketone, methyl isobutyl ketone, etc., aliphatic hydrocarbon solvents such as pentane, hexane, heptane, etc., aromatic hydrocarbon solvents such as toluene, xylene, etc., nitrile solvents such as acetonitrile, etc. , ether solvents such as tetrahydrofuran and dimethoxyethane, and chlorinated hydrocarbon solvents such as chloroform and chlorobenzene. These solvents can be used alone or in combination of two or more. The content of the solvent is preferably in the range of 100 to 1900 parts by mass, more preferably in the range of 150 to 900 parts by mass, and particularly preferably 180 parts by mass relative to 100 parts by mass of the solid content constituting the polymerizable liquid crystal composition (A'). Within the range of ~600 parts by mass.

Examples of methods for applying the polarizing sub-layer forming composition to a base material include spin coating, extrusion, gravure coating, die coating, rod coating, and applicator methods. Well-known methods such as coating methods, flexographic printing methods, etc.

Next, under the condition that the polymerizable liquid crystal compound contained in the coating film obtained from the polarizing sub-layer forming composition does not polymerize, the solvent is removed by drying or the like to form a dry coating film. Examples of drying methods include natural drying, ventilation drying, heating drying, and reduced pressure drying.

Furthermore, in order to phase-transfer the polymerizable liquid crystal compound to the liquid phase, the temperature is raised to or above the temperature at which the polymerizable liquid crystal compound phase-transfers to the liquid phase, and then the temperature is lowered to phase-transfer the polymerizable liquid crystal compound to the smectic phase (smectic liquid crystal). condition). This phase transfer is performed after the solvent in the coating film is removed, or simultaneously with the removal of the solvent.

By maintaining the smectic liquid crystal state of the polymerizable liquid crystal compound, the polymerizable liquid crystal compound is polymerized, and a polarizing sublayer is formed as a hardened layer of the polymerizable liquid crystal composition. As the polymerization method, photopolymerization is preferred. In photopolymerization, the light irradiated to the dry coating film can be determined according to the type of the polymerizable liquid crystal compound contained in the dry coating film (especially the type of polymerizable group the polymerizable liquid crystal compound has), the polymerization initiation The appropriate selection depends on the types of agents and their amounts.

Specific examples thereof include one or more active energy rays or active electron rays selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays and γ-rays. Among them, ultraviolet light is preferred because it is easy to control the progress of the polymerization reaction, or the photopolymerization device can be used by a wide range of users in this field, and photopolymerization by ultraviolet light energy is preferred. Select the type of polymerizable liquid crystal compound or polymerization initiator contained in the polymerizable liquid crystal composition.

Furthermore, during polymerization, the polymerization temperature can be controlled by irradiating the film with light while cooling and drying the coating film using an appropriate cooling means. If such a cooling means is used to polymerize the polymerizable liquid crystal compound at a lower temperature, the polarizing sublayer can be formed appropriately even if a base material with relatively low heat resistance is used. During photopolymerization, a patterned polarizing sub-layer can also be obtained by masking or developing.

Examples of light sources of active energy rays include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten lamps, gallium lamps, excimer lasers, and emission wavelength ranges of 380 ~440nm LED light source, chemical lamp, black light lamp, microwave excited mercury lamp, metal halide lamp, etc.

The intensity of ultraviolet irradiation is usually in the range of 10~3000mW/ ^cm2 . The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activation of the polymerization initiator. The time of irradiation with light is usually in the range of 0.1 seconds to 10 minutes, preferably in the range of 1 second to 5 minutes, more preferably in the range of 5 seconds to 3 minutes, especially in the range of 10 seconds to 1 minute . If the ultraviolet irradiation intensity is irradiated once or multiple times, the cumulative light amount is in the range of 10~3000 mJ/ ^cm2 , preferably in the range of 50~2000mJ/ ^cm2 , and more preferably in the range of 100~1000mJ/cm2 Within the range of cm ² .

By carrying out photopolymerization, the polymerizable liquid crystal compound maintains a smectic phase, preferably a liquid crystal state of a higher-order smectic phase, and polymerizes to form a polarizing sublayer. The polarizing sub-layer obtained by polymerizing the polymerizable liquid crystal compound while maintaining the liquid crystal state of the smectic phase is also accompanied by the action of the aforementioned dichroic pigment. It is different from the conventional host-guest polarizing plate, which is composed of the liquid crystal state of the nematic phase. Compared with the polarizing sub-layer, it has the advantage of high polarizing performance. Furthermore, it also has the advantage of being superior in strength compared to coating only dichroic dyes or lyotropic liquid crystals.

＜Manufacturing method of liquid crystal alignment layer＞ In the present invention, the polarizing sub-layer is preferably formed through the liquid crystal alignment layer. The liquid crystal alignment layer has an alignment control force that aligns the polymerizable liquid crystal compound in a desired direction.

The liquid crystal alignment layer preferably has solvent resistance such that it is not dissolved by coating of a composition containing a polymerizable liquid crystal compound. Furthermore, it is preferable to have heat resistance during heat treatment for removal of solvent or alignment of the polymerizable liquid crystal compound. In the present invention, the liquid crystal alignment layer is preferably an optical liquid crystal alignment layer from the viewpoints of the accuracy and quality of the alignment angle and the water resistance and bendability of the polarizing plate containing the liquid crystal alignment layer. The optical liquid crystal alignment layer is also advantageous in that the direction of the alignment control force can be arbitrarily controlled by selecting the polarization direction of the irradiated polarized light.

The optical liquid crystal alignment layer is usually formed by coating a composition containing a polymer or monomer with a photoreactive group and a solvent (hereinafter also referred to as the "optical liquid crystal alignment layer forming composition") on a substrate, and then irradiating polarized light ( Preferably "polarized UV").

The so-called photoreactive group refers to a group that generates liquid crystal alignment ability through light irradiation. Specific examples include photoreactions that are involved in the origin of the alignment ability of liquid crystals, such as alignment induction of molecules produced by light irradiation, isomerization reaction, dimerization reaction, photocrosslinking reaction, or photodecomposition reaction. base. Among them, groups participating in dimerization reaction or photo-crosslinking reaction are preferred because they have excellent alignment properties. The photoreactive group is preferably a group having an unsaturated bond, especially a double bond, and particularly preferably a group having a carbon-carbon double bond (C=C bond), a carbon-nitrogen double bond (C=N bond), nitrogen - A group of at least one of the group consisting of a nitrogen double bond (N=N bond) and a carbon-oxygen double bond (C=O bond).

Examples of the photoreactive group having a C=C bond include a vinyl group, a polyalkenyl group, a distyryl group, a styrylpyridyl group, a styrylpyridinium group, a chalcone group, a cinnamyl group, and the like. Examples of the photoreactive group having a C=N bond include groups having structures such as aromatic Schiff bases and aromatic hydrazones. Examples of the photoreactive group having an N=N bond include an azophenyl group, an azonaphthyl group, an aromatic heterocyclic azo group, a disazo group, a methyl group, and a group having an oxidized azobenzene structure. wait. Examples of the photoreactive group having a C=O bond include a benzophenone group, a coumarin group, an anthraquinone group, a maleimide group, and the like. These groups may be substituted by substituents such as alkyl, alkoxy, aryl, allyloxy, cyano, alkoxycarbonyl, hydroxyl, sulfonic acid, alkyl halide and the like.

Among them, a photoreactive group that participates in the photodimerization reaction is preferred because the amount of polarized light irradiation required for photoalignment is relatively small and it is easy to obtain a photoliquid crystal alignment layer that is excellent in thermal stability or stability over time. , preferably cinnamon base and chalcone base. The polymer having a photoreactive group is particularly preferably a polymer having a cinnamyl group at the end of the side chain such as a cinnamic acid structure.

By coating the composition for forming a photo-liquid crystal alignment layer on a substrate, a photo-alignment inducing layer can be formed on the substrate. Examples of the solvent contained in the composition include the same solvents exemplified previously as solvents that can be used when forming the polarizing sublayer, and can be appropriately selected according to the solubility of the polymer or monomer having a photoreactive group. .

The content of the polymer or monomer having a photoreactive group in the composition for forming the optical liquid crystal alignment layer can be appropriately adjusted according to the type of polymer or monomer or the thickness of the intended optical liquid crystal alignment layer, but relative to the The mass of the composition for forming the liquid crystal alignment layer is preferably at least 0.2 mass%, more preferably in the range of 0.3 to 10 mass%. Within the scope of not significantly damaging the characteristics of the optical liquid crystal alignment layer, the composition for forming the optical liquid crystal alignment layer may also include polymer materials such as polyvinyl alcohol or polyimide or photosensitizers.

As a method of applying the composition for forming an optical liquid crystal alignment layer on a substrate and a method of removing a solvent from the applied composition for forming an optical liquid crystal alignment layer, examples of the method include applying the composition for forming a polarizing sub-layer. The method of applying to the substrate and removing the solvent are the same.

The irradiation of polarized UV may be in the form of directly irradiating polarized UV after removing the solvent from the composition for forming the optical liquid crystal alignment layer coated on the substrate, or may be irradiated with polarized UV from the side of the substrate, so that the polarized UV A form of irradiation through. In addition, the polarized UV is preferably substantially parallel light. The wavelength of the irradiated polarized light may be a wavelength region in which the photoreactive groups of the polymer or monomer having photoreactive groups can absorb light energy. Specifically, UV (ultraviolet) with a wavelength in the range of 250 to 400 nm is particularly preferred.

Examples of light sources used for polarized UV irradiation include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, KrF, ArF and other ultraviolet lasers, and more preferably high-pressure mercury lamps, ultra-high pressure mercury lamps and metal halide lamps. Object lamp. Among them, high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps are preferred because of the high luminous intensity of ultraviolet light with a wavelength of 313 nm. By irradiating light from the aforementioned light source with appropriate polarized photons, polarized UV can be irradiated. As this polarizer, a polarizing filter, a polarizing filter such as Glan-Thomson, Glan-Taylor, etc., or a wire grid type polarizer can be used.

Furthermore, if masking is performed during rubbing or polarized light irradiation, a plurality of regions (patterns) with different liquid crystal alignment directions can be formed.

[3.2] Phase difference film The polarizing plate of the present invention, as shown in FIG. 4B , may be a polarizing plate (for example, an elliptical polarizing plate) including a retardation film as a film (opposing film) different from the aforementioned optical film. In the polarizing plate of the present invention, the retardation film preferably satisfies the following retardation value (phase difference value).

better to satisfy [In the formula, Ro (550) represents the in-plane retardation value at a wavelength of 550 nm] If the retardation film has the in-plane retardation value represented by the above formula X, it functions as a so-called λ/4 plate. From the viewpoint of optical performance, the aforementioned formula

In the polarizing plate of the present invention, the angle formed by the slow axis of the retardation film and the absorption axis of the polarizing plate is preferably substantially 45°. In addition, the so-called "substantially 45°" in the present invention means 45°±5°.

Furthermore, the aforementioned retardation film preferably satisfies: [In the formula, Ro (450) and Ro (550) respectively represent the in-plane retardation value at wavelengths of 450 nm and 550 nm] The retardation film satisfying the above formula Y has the so-called reverse wavelength dispersion property, which is shown Excellent polarizing properties. The value of Ro(450)/Ro(550) is preferably 0.93 or less, more preferably 0.88 or less, particularly preferably 0.86 or less, preferably 0.80 or more, more preferably 0.82 or more.

The retardation film may be a stretched film in which a phase difference is imparted by stretching a polymer. However, from the viewpoint of thinning the polarizing plate, it is preferably composed of a polymerizable liquid crystal containing a polymerizable liquid crystal compound. (hereinafter also referred to as "polymerizable liquid crystal composition (B')").

5C is a cross-sectional view showing an example of a polarizing plate in which the retardation film is composed of a polymerizable liquid crystal composition containing a polymer of a polymerizable liquid crystal compound.

The polarizing plate 70 with a retardation layer is laminated with the laminated film of the present invention composed of the optical film 1, the adhesive layer 2 and the release film 3 and the polarizing sub-layer 21 and the liquid crystal alignment layer 22 through the adhesive layer 24. The constituted unit is composed of a retardation film unit composed of a support 26, a liquid crystal alignment layer 22, and a polymerizable liquid crystal compound containing layer 25. Furthermore, a barrier layer 27 may be formed adjacent to the polarizing sub-layer 21 .

The polymerizable liquid crystal compound in the retardation film is usually polymerized in an aligned state. The polymerizable liquid crystal compound that forms a retardation film (hereinafter also referred to as "polymerizable liquid crystal compound (B')") means a liquid crystal compound having a polymerizable functional group, especially a photopolymerizable functional group. The photopolymerizable functional group refers to a group that can participate in the polymerization reaction through active radicals or acids generated from the photopolymerization initiator.

Examples of the photopolymerizable functional group include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloxy, methacryloxy, and ethylene oxide. base, oxetanyl, etc. Among them, an acryloxy group, a methacryloxy group, an vinyloxy group, an oxirane group and an oxetanyl group are preferred, and an acryloxy group is more preferred. The liquid crystallinity can be thermotropic liquid crystal or lyotropic liquid crystal, and the phase order structure can be nematic liquid crystal or smectic liquid crystal. As the polymerizable liquid crystal compound, only one type may be used, or two or more types may be combined.

The polymerizable liquid crystal compound (B') is preferably one having the following characteristics (ㄅ) to (ㄈ) from the viewpoint of ease of film formation and imparting retardation properties represented by the aforementioned formula (Y). compound.

(ㄅ) A compound having thermotropic liquid crystallinity. (ㄆ) The polymerizable liquid crystal compound has π electrons in the long axis direction (a). (ㄇ) There are π electrons in the direction intersecting the major axis direction (a) [crossing direction (b)]. (ㄈ) Let the total number of π electrons existing in the long axis direction (a) be regarded as N(πa), and the total number of molecular weights existing in the long axis direction be regarded as N(Aa), and it will be defined by the following formula (i) The π electron density in the long axis direction (a) of the polymerizable liquid crystal compound: The total number of π electrons present in the cross direction (b) is regarded as N(πb), and the total number of molecular weights present in the cross direction (b) is regarded as N(Ab). The polymerizability defined by the following formula (ii) π electron density in the cross direction (b) of liquid crystal compounds: in The relationship [that is, the π electron density in the cross direction (b) is greater than the π electron density in the long axis direction (a)].

Furthermore, the polymerizable liquid crystal compound (B') that satisfies the above (ㄅ) to (ㄈ) can be formed into a nematic phase by, for example, coating the liquid crystal alignment layer formed by rubbing treatment and heating it to a phase transition temperature or higher. In the nematic phase formed by aligning the polymerizable liquid crystal compound (B'), the polymerizable liquid crystal compound (B') is usually aligned so that its long axis directions become parallel to each other, and the long axis directions become the alignment direction of the nematic phase.

The polymerizable liquid crystal compound (B') having the above characteristics generally shows reverse wavelength dispersion. Specific examples of compounds that satisfy the characteristics (ㄅ) to ((ㄈ)) include compounds represented by the following formula (II).

The compound represented by the said formula (II) can be used individually or in combination of 2 or more types.

In formula (II), Ar represents a divalent aromatic group which may have a substituent. The aromatic group mentioned here is the base of a planar cyclic structure, which means that the number of π electrons in the cyclic structure is [4n+2] according to Hückel’s rule. Here, n represents an integer. When a ring structure is formed by containing heteroatoms such as -N= or -S-, the non-covalent electron pairs on these heteroatoms are included, satisfying Huckel's rule, and it also includes aromatic properties. The divalent aromatic group preferably contains at least one of a nitrogen atom, an oxygen atom, and a sulfur atom.

In formula (II), G ¹ and G ² each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, or a fluoroalkyl group having 1 carbon atoms. ~4 alkoxy group, cyano group or nitro group, the carbon atoms constituting the divalent aromatic group or divalent alicyclic hydrocarbon group can be substituted with oxygen atoms, sulfur atoms or nitrogen atoms.

In formula (II), L ¹ , L ² , B ¹ and B ² are each independently a single bond or a bivalent linking group.

In formula (II), k and l each independently represent an integer from 0 to 3, satisfying the relationship of 1≦k+l. Here, when 2≦k+1, B ¹ and B ² and G ¹ and G ² may be the same as each other or may be different.

In formula (II), E ¹ and E ² each independently represent an alkanediyl group having 1 to 17 carbon atoms. Here, the hydrogen atom contained in the alkanediyl group may be replaced by a halogen atom. The alkanediyl group contains -CH ₂ - can be replaced by -O-, -S-, -Si-. P ¹ and P ² independently represent a polymerizable group or a hydrogen atom, and at least one of them is a polymerizable group.

In formula (11), G ¹ and G ² are each independently preferably substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms. -phenylenediyl, 1,4-cyclohexanediyl which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably 1,4-phenylenediyl substituted by methyl group, unsubstituted 1,4-phenylenediyl or unsubstituted 1,4-trans-cyclohexanediyl, especially unsubstituted 1,4-phenylenediyl or unsubstituted 1,4-trans-cyclohexanediyl. Furthermore, at least one of G ¹ and G ² present in plural is preferably a divalent alicyclic hydrocarbon group, and at least one of G ¹ and G ² bonded to L ¹ or L ² is more preferably a divalent alicyclic hydrocarbon group. Valent alicyclic hydrocarbon group.

In formula (II), L ¹ and L ² are preferably each independently a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a1 OR ^a2 -, -R ^a3 COOR ^a4 -, -R ^a5 OCOR ^a6 -, R ^a7 OC=OOR ^a8 -, -N=N-, -CR ^c =CR ^d -or C≡C-. Here, R ^a1 to R ^a8 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms, and R ^c and R ^d represent an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L ¹ and L ² are each independently more preferably a single bond, -OR ^a2-1 -, -CH ₂ -, -CH ₂ CH ₂ -, -COOR ^a4-1 - or OCOR ^a6-1 -. Here, R ^a2-1 , R ^a4-1 , and R ^a6-1 each independently represent any one of a single bond, -CH ₂ -, and -CH ₂ CH ₂ -. L ¹ and L ² are preferably each independently a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ - or OCO-.

In a suitable embodiment of the present invention, at least one of G ¹ and G ² in formula (II) is a divalent alicyclic hydrocarbon group, and the divalent alicyclic hydrocarbon group may have a substituent by A polymerizable liquid crystal compound in which the divalent aromatic group Ar is bonded to L ¹ and/or L ² of -COO-.

In formula (II), B ¹ and B ² are preferably each independently a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R ^a9 ORa ¹⁰ -, -R ^a11 COOR ^a12 -, -R ^a13 OCOR ^a14 - or R ^a15 OC=OOR ^a16 -. Here, R ^a9 to R ^a16 each independently represent a single bond or an alkylene group having 1 to 4 carbon atoms. B ¹ and B ² are each independently more preferably a single bond, -OR ^a10-1 -, -CH ₂ -, -CH ₂ CH ₂ -, -COOR ^a12-1 - or OCOR ^a14-1 -. Here, R ^a10-1 , R ^a12-1 , and R ^a14-1 each independently represent any one of a single bond, -CH ₂ -, and -CH ₂ CH ₂ -. B ¹ and B ² are each independently preferably a single bond, -O-, -CH ₂ CH ₂ -, -COO-, -COOCH ₂ CH ₂ -, -OCO- or OCOCH ₂ CH ₂ -.

In formula (II), from the viewpoint of showing reverse wavelength dispersion, k and l are preferably in the range of 2≦k+l≦6, more preferably k+l=4, and particularly preferably k=2 and l =2. If k=2 and l=2, it is better because it becomes a symmetrical structure.

In formula (II), E ¹ and E ² are each independently preferably an alkanediyl group having 1 to 17 carbon atoms, more preferably an alkanediyl group having 4 to 12 carbon atoms.

In formula (II), examples of the polymerizable group represented by P ¹ or P ² include epoxy group, vinyl group, vinyloxy group, 1-chlorovinyl group, isopropenyl group, and 4-vinylphenyl group. , acryloxy group, methacryloxy group, ethylene oxide group and oxetanyl group, etc. Among these, an acryloxy group, a methacryloyloxy group, an vinyloxy group, an ethylene oxide group, and an oxetanyl group are preferable, and an acrylyloxy group is more preferable.

In formula (II), Ar preferably has at least one selected from an aromatic hydrocarbon ring that may have a substituent, an aromatic heterocyclic ring that may have a substituent, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, and the like, and a benzene ring and a naphthalene ring are preferred. Examples of the aromatic heterocyclic ring include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyridine ring, a pyrimidine ring, a triazole ring, and a trisulfate ring. , pyrroline ring, imidazole ring, pyrazole ring, thiazole ring, benzothiazole ring, thienothiazole ring, 㗁azole ring, benzothezole ring and phenanthroline ring, etc. Among these, it is preferable to have a thiazole ring, a thiazole ring or a benzofuran ring, and it is more preferable to have a benzothiazolyl group. Furthermore, when Ar contains a nitrogen atom, the nitrogen atom preferably has π electrons.

In formula (II), the total number Nπ of π electrons contained in the divalent aromatic group represented by Ar is preferably 8 or more, more preferably 10 or more, still more preferably 14 or more, particularly preferably 16 or more. Furthermore, the number is preferably 30 or less, more preferably 26 or less, and particularly preferably 24 or less.

Examples of the aromatic group represented by Ar include groups represented by the following formulas (Ar-1) to (Ar-23).

In the formula (Ar-1) to the formula (Ar-23), the * mark represents a connecting part, and Z ⁰ , Z ¹ and Z ² each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, and a cyano group. , nitro group, alkylsulfenyl group with 1 to 12 carbon atoms, alkylsulfinyl group with 1 to 12 carbon atoms, carboxyl group, fluoroalkyl group with 1 to 12 carbon atoms, alkoxy group with 1 to 6 carbon atoms , Alkylthio group with 1 to 12 carbon atoms, N-alkylamino group with 1 to 12 carbon atoms, N,N-dialkylamino group with 2 to 12 carbon atoms, N-alkyl group with 1 to 12 carbon atoms Aminosulfonyl group or N,N-dialkylaminesulfonyl group with 2 to 12 carbon atoms.

In formula (Ar-1) to formula (Ar-23), Q ¹ and Q ² each independently represent -CR ^2' R ^3'- , -S-, -NH-, -NR ^2' -, -CO- Or O-, R ^2' and R ^3' each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

In formulas (Ar-1) to formula (Ar-23), J ¹ and J ² each independently represent a carbon atom or a nitrogen atom.

In formulas (Ar-1) to formula (Ar-23), Y ¹ , Y ² and Y ³ each independently represent an aromatic hydrocarbon group or an aromatic heterocyclic group which may be substituted.

In formula (Ar-1) to formula (Ar-23), W ¹ and W ² each independently represent a hydrogen atom, a cyano group, a methyl group or a halogen atom, and m represents an integer from 0 to 6.

Examples of the aromatic hydrocarbon group in Y ¹ , Y ² and Y ³ include aromatic hydrocarbon groups having 6 to 20 carbon atoms such as phenyl, naphthyl, anthracenyl, phenanthrenyl, and biphenyl groups, with phenyl being preferred. , naphthyl, more preferably phenyl. The aromatic heterocyclic group is preferably a furyl group, a pyrrolyl group, a thienyl group, a pyridyl group, a thiazolyl group, a benzothiazolyl group, and the like, with a carbon number of 4 and containing at least one heteroatom such as a nitrogen atom, an oxygen atom, a sulfur atom, etc. ~20 aromatic heterocyclyl, furyl, thienyl, pyridyl, thiazolyl, benzothiazolyl.

Y ¹ and Y ² may each independently be a polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group which may be substituted. The polycyclic aromatic hydrocarbon group refers to a condensed polycyclic aromatic hydrocarbon group or a group derived from a collection of aromatic rings. The polycyclic aromatic heterocyclic group refers to a condensed polycyclic aromatic heterocyclic group or a group derived from a collection of aromatic rings.

In formula (Ar-1) to formula (Ar-23), Z ⁰ , Z ¹ and Z ² are preferably each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, An alkoxy group having 1 to 12 carbon atoms, Z ⁰ is more preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a cyano group, and Z ¹ and Z ² are more preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group, Cyano.

In formula (Ar-1) ~ formula (Ar-23), Q ¹ and Q ² are preferably -NH-, -S-, -NR ^2' -, -O-, and R ^2' is preferably a hydrogen atom . Among them, -S-, -O- and -NH- are particularly preferred.

Among formulas (Ar-1) to (Ar-23), from the viewpoint of molecular stability, (Ar-6) and formula (Ar-7) are more preferred.

In formulas (Ar-17) ~ (Ar-23), Y ¹ can form an aromatic heterocyclic group with its bonded nitrogen atom and Z ⁰ . Examples of the aromatic heterocyclic group include those mentioned above as aromatic heterocyclic rings that Ar may have. Examples include a pyrrole ring, an imidazole ring, a pyrroline ring, a pyridine ring, a pyridine ring, a pyrimidine ring, and an indole ring. , quinoline ring, isoquinoline ring, purine ring, pyrrolidine ring, etc. The aromatic heterocyclic group may have a substituent. In addition, Y ¹ , together with the nitrogen atom and Z ⁰ to which it is bonded, may be the aforementioned polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group which may be substituted. For example, a benzofuran ring, a benzothiazole ring, a benzothezole ring, etc. are mentioned. The compound represented by the formula (II) can be produced according to the method described in Japanese Patent Application Laid-Open No. 2010-31223, for example.

The content of the polymerizable liquid crystal compound (B') in the polymerizable liquid crystal composition (B') constituting the retardation film is, for example, 70 to 99.5 with respect to 100 parts by mass of the solid content of the polymerizable liquid crystal composition (B'). Within the range of parts by mass, preferably within the range of 80 to 99 parts by mass, more preferably within the range of 90 to 98 parts by mass. If the content is within the above range, the alignment of the retardation film tends to become high. Here, the solid content refers to the total amount of components in the polymerizable liquid crystal composition (B') after removing volatile components such as solvents.

The polymerizable liquid crystal composition (B') may include a polymerization initiator for starting the polymerization reaction of the polymerizable liquid crystal compound (B'). The polymerization initiator can be appropriately selected and used from those skilled in the field. It can be a thermal polymerization initiator or a photopolymerization initiator. However, insofar as the polymerization reaction can be started under lower temperature conditions, Preferred is a photopolymerization initiator. Suitable examples thereof include the same ones as those exemplified above as photopolymerization initiators that can be used in the polymerizable liquid crystal composition (A').

The polymerizable liquid crystal composition (B') may optionally contain a photosensitizer, a leveling agent, additives exemplified as additives contained in the polymerizable liquid crystal composition (A'), and the like. Examples of the photosensitizer and leveling agent include those exemplified above as those usable in the polymerizable liquid crystal composition (A').

The retardation film can be prepared by, for example, adding a polymerizable liquid crystal composition (B') containing a polymerizable liquid crystal compound (B') and optional polymerization initiator, additives, etc. to a solvent, and mixing and stirring the composition. (hereinafter also referred to as "composition for forming a retardation film"), apply it on the substrate or liquid crystal alignment layer, remove the solvent by drying, and make the resulting coating by heating and/or active energy rays. It is obtained by hardening the polymerizable liquid crystal compound (B') in the film. Examples of the base material and/or the liquid crystal alignment layer used for the production of the retardation film include the same ones as those previously exemplified by the user when producing the polarizing sub-layer of the present invention.

The solvent used for the retardation film-forming composition, the coating method of the retardation film-forming composition, the hardening conditions of the active energy rays, etc. are all those that can be used in the production method of the polarizing sublayer of the present invention. Same thing.

The thickness of the retardation film can be appropriately selected according to the display device to which it is applied. However, from the viewpoint of thinness and flexibility, it is preferably in the range of 0.1 to 10 μm, and more preferably in the range of 1 to 5 μm. Preferably it is within the range of 1~3μm.

[3.3] Adhesion layer The adhesive layer in the polarizing plate of the present invention is not particularly limited in terms of material as long as it is a transparent material that can bond the polarizing sub-layer and the retardation film, the optical film as a protective layer, or various functional layers. Examples of adhesives include water-based adhesives, photosensitive adhesives, pressure-sensitive adhesives, and the like.

Examples of resins used for water-based adhesives include epoxy resins. The epoxy resin may be, for example, hydrogenated epoxy resin, alicyclic epoxy resin or aliphatic epoxy resin. A polymerization initiator (photocationic polymerization initiator, thermal cationic polymerization initiator, photoradical polymerization initiator or thermal radical polymerization initiator, etc.) or other additives (sensitizer, etc.) can be added to the ring. Oxygen resin.

Examples of other resins include acrylic resins such as acrylamide, acrylate, urethane acrylate, and epoxy acrylate, or polyvinyl alcohol-based resins.

Examples of the resin used for the pressure-sensitive adhesive include acrylic resin, polysiloxy resin, polyester, polyurethane, polyether, and the like.

The thickness of the subsequent layer is preferably in the range of 0.01~5 μm, more preferably in the range of 0.05~3 μm, especially preferably in the range of 0.1~1 μm. When using a pressure-sensitive adhesive, the thickness of the adhesive layer is preferably in the range of 2 to 500 μm, more preferably in the range of 2 to 200 μm, and particularly preferably in the range of 2 to 50 μm.

≪4 Manufacturing method of polarizing plate roll material of the present invention≫ The manufacturing method of the polarizing plate roll of the present invention is a manufacturing method of the polarizing plate roll manufactured by following the following steps: on the side of the aforementioned optical film of a laminated film composed of at least an optical film, an adhesive layer and a release film, The laminating step of combining polarized photons to make a polarizing plate, and the winding step of winding the aforementioned polarizing plate; characterized in that: the film thickness of the aforementioned adhesive layer is 1 μm to less than 10 μm, and the film thickness of the optical film is 1 μm to less than 1 μm. up to 10μm.

In the manufacturing method of the polarizing plate roll of the present invention, when winding up the polarizing plate, it is preferable to also wind up the release film. That is, it is preferable from the viewpoint of productivity and durability to roll up the adhesive layer without exposing it.

In addition, in the manufacturing method of the polarizing plate roll of the present invention, it is preferable from the viewpoint of productivity and durability that the release film in the laminated film is rolled up without being peeled off in an intermediate step. That is, the support of the protective film on the side that previously contacted the optical film is peeled off first, and that side is processed first and then processed. Since water-based and solvent-based adhesives are used during the bonding process, in order not to reduce the durable adhesiveness after bonding, the support on the side that contacts the optical film is peeled off first, and the release film on the adhesive layer side is peeled off later, and the bonding process is performed. , that is, it is better to process without peeling off the release film.

[4.1] Manufacturing method of polarizing plate coil 4A is a cross-sectional view showing the basic structure of the layer structure of the polarizing plate roll material of the present invention. In addition, it may have a retardation film or a liquid crystal alignment layer, and may also include other layers (adhesion layer, etc.) besides these.

The laminated film of the present invention can be produced by using the aforementioned laminated film and winding it into a roll shape by the aforementioned manufacturing method. In addition, the laminated film is rolled up with a support, and the support functions as a protective film to prevent damage to the optical film, suppress curling, and facilitate handling.

In addition, the polarizing sub-layer of the present invention is not particularly limited. Preferably, for the polarizing plate 70 shown in FIG. 5A , the laminated film and the polarizing sub-layer 21 are separately produced and bonded together, and more preferably, the polarizing sub-layer 28 is bonded together. In addition, when manufacturing by coating the polarizing sub-layer, manufacturing by lamination is also included. For the polarizing plate 70 shown in FIG. 5B , the polarizing sub-layer 21 can be manufactured by the aforementioned polarizing sub-layer forming step, preferably by coating on the optical film 1 through the liquid crystal alignment layer 22 . In manufacturing by coating, since the polarizing sub-layer can be thinned, a thinner polarizing plate can be obtained while maintaining durability against repeated folding operations. In addition, in order to further improve the durability, a protective layer can be formed above the polarizing sub-layer. The protective layer can be further coated with the barrier layer 27 and/or adhered to the optical film 1 of the present invention.

In the manufacturing method of the polarizing plate roll of the present invention, when laminating the polarizing sub-layer, it is preferable to include the steps of forming the polarizing sub-layer, the step of forming an adhesive layer on the polarizing sub-layer, and the step of laminating to the polarizing sub-layer. , the step of rolling up the polarizing plate produced. Furthermore, when the laminated film has a support (film), it is preferable to include a step of peeling off the support.

An example of a manufacturing method of a polarizing plate roll is shown in FIG. 6 . That is, the example shown in FIG. 6 is a manufacturing method in which the laminated film 50, the polarizer layer 21 and the polarizer protective layer 28 are bonded together through the adhesive layer 24. In this manufacturing method, the polarizing plate roll is manufactured through the following steps: the step of forming the polarizing sub-layer 21, the step of forming the polarizing sub-protective layer 28, the step of peeling the support 4 from the laminated film 50, and the step of forming the polarizing sub-layer on the polarizing sub-layer. The steps of forming the adhesive layer 24 , the step of bonding the optical film 1 , the polarizer layer 21 and the polarizer protective layer 28 in the laminated film 50 to form the polarizer 70 , and the step of winding up the polarizer 70 .

Furthermore, in the conventional general manufacturing method, there are steps of peeling off the release film and bonding the protective film in the middle. However, in the above-mentioned manufacturing method of the present invention, it is characterized in that the step of peeling off the release film in the middle is not carried out. Peel off and take up. That is, the characteristic is that the release film does not change during the process and is the same release film. In this way, there is no waste of materials and the number of work steps can be reduced.

Furthermore, by winding it up with the release film, the adhesive layer is prevented from adhering to the manufacturing equipment, the support, etc. Moreover, it can be easily formed into an appropriate shape. Furthermore, when the polarizing sub-layer is bonded through the adhesive layer, the component with the adhesive function is to volatilize the water or solvent contained in the adhesive. During the period until it dries, it must penetrate both sides to some extent. If the film to be bonded is too thin, the moisture or solvent will evaporate too quickly and drying will be completed before the ingredients are fully penetrated. In this case, the adhesion force will be reduced. In the laminated film of the present invention, the moisture or residual solvent in the adhesive layer further diffuses from the optical film to the adhesive layer, but the diffusion is restricted because the adhesive layer is in contact with the release film. Therefore, the penetration time, which is important in ensuring adhesion, can be sufficiently ensured, and the adhesive force of the adhesive layer can be maintained.

Furthermore, in the manufacturing method of the polarizing plate roll of the present invention, when coating the polarizing sub-layer, it is preferable to include the steps of peeling off the support from the laminated film, and coating the liquid crystal alignment layer and the polarizing sub-layer on the optical film. Steps to roll up the polarizing plate produced. The method of forming the liquid crystal alignment layer and the polarizing sub-layer on the optical film by coating is as described above.

[4.2] Manufacturing equipment for polarizing plate rolls As an apparatus for carrying out the manufacturing method of the polarizing plate roll of the present invention, any apparatus having the following means is sufficient: having the optical film surface on the surface of the laminated film composed of at least an optical film, an adhesive layer, and a release film. A device for manufacturing a polarizing plate film by laminating the polarizing sub-layer side by side and a device for winding up the polarizing plate film (see Figure 6), or forming a polarizing sub-layer by coating on the optical film side of the laminated film , the method of making polarizing plate film, and the method of rolling and rolling the aforementioned polarizing plate film.

[4.3] Manufacturing method of polarizing plate roll with glass plate The polarizing plate roll of the present invention is preferably a polarizing plate roll with a glass plate that is bonded to the glass plate. Usually, the glass plate and the polarizing plate used as the outermost layer of the display are both thin films, so each requires a protective film. However, since the laminated film of the present invention has the function of protecting both the polarizing sub-layer and the glass plate, by producing a polarizing plate roll that integrates the glass plate and the polarizing plate, the protective film can be reduced and a thinner film with Display durability for repeated folding movements.

As the glass plate, the glass plate mentioned above (≪2 Laminate≫) can be suitably used. An example of a manufacturing method of a polarizing plate roll with a glass plate is shown in FIG. 7 . A manufacturing method, which includes: peeling off the release film 3 from the polarizing plate 70 of the present invention, bonding the adhesive layer 2 and the glass plate 11 in the polarizing plate 70 to produce the polarizing plate 80 with the glass plate, and The step of winding up the polarizing plate 80 with the glass plate mentioned above. The polarizing plate 70 can be produced by any method of lamination or coating. When produced by coating, as shown in FIG. 7 , the polarizing plate 70 preferably includes a liquid crystal alignment layer 22 and a barrier layer 27 . Furthermore, this method of producing a polarizing plate roll that integrates the transparent substrate for the outermost layer and the polarizing plate can be used not only when the outermost layer is a glass plate, but also when transparent polyimide is used. It eases the stress exerted on the outermost surface, so it is effective in suppressing wrinkles and whitening during bending.

≪5 display device≫ The display device of the present invention includes the laminated film of the present invention. The display device of the present invention can be obtained, for example, by bonding the polarizing plate of the present invention to a substrate in the display device through an adhesive layer. The thickness of the substrate is preferably in the range of 10 to 100 μm from the viewpoint of durability of the folding operation. The substrate is not particularly limited, but is preferably a glass plate or thermoplastic resin. The so-called display device is a device with a display mechanism, including a light-emitting element or a light-emitting device as a light source. Examples of the display device include a liquid crystal display device, an organic electroluminescence (EL) display device, an inorganic electroluminescence (EL) display device, a touch panel display device, and an electron emission display device (field emission display device (FED, etc.) , Surface electric field emission display device (SED)), electronic paper (display device using electronic ink or electrophoretic components), plasma display device, projection display device (with gate light valve (GLV) display device, digital micromirror device (DMD) display devices, etc.) and piezoelectric ceramic displays, etc.

The liquid crystal display device includes any one of a transmissive liquid crystal display device, a semi-transmissive liquid crystal display device, a reflective liquid crystal display device, a direct-viewing liquid crystal display device, a projection-type liquid crystal display device, and the like. These display devices may be display devices that display two-dimensional images, or they may be three-dimensional display devices that display three-dimensional images. In particular, as the display device of the present invention, an organic EL display device and a touch panel display device are preferred, and an organic EL display device is particularly preferred.

In addition, the foldable display is preferably a continuous single-piece display that can be folded in half to reduce the size by half when being carried, so as to have a structure that improves portability, and is more preferably thin and lightweight. Therefore, the bending radius of the foldable display is preferably 5 mm or less, and more preferably 3 mm or less. If the bending radius is 5 mm or less, thinning is possible in the folded state. The smaller the bending radius, the better, but it does not matter if it is 0.1mm or more, and it does not matter if it is 0.5mm or more. Even if it is 1mm or more, the practicality is better than that of the conventional display without a folding structure. The so-called bending radius when folded is to measure the R position when the display 90 in the model diagram of FIG. 8 is folded, and refers to the radius of a circle that approximates the curved portion of the folded portion during folding with an arc.

According to this embodiment, the display device of the present invention is less likely to be damaged or degraded even if the folding operation is repeated, and the visibility of the display is excellent even if the folding operation is repeated under high temperature and high humidity conditions such as outdoors. For example, mobile terminal devices equipped with this foldable display provide beautiful images, are rich in functionality, and are excellent in convenience such as portability. [Example]

The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. Furthermore, the expression "part" or "%" is used in the examples. Unless otherwise specified in advance, it means "part by mass" or "% by mass".

(Example 1) ≪Production of laminated film≫ [Production of optical films] ＜Production of optical film 1＞ (support body) As a support, a polyethylene terephthalate film (PET film) was used: (TN100 manufactured by Toyobo Co., Ltd., release layer containing a non-polysilicone release agent, thickness 38 μm).

(Preparation of solution for optical film 1) The following components were mixed to obtain a solution for optical film 1.

Dichloromethane (boiling point 41°C) 800 parts by mass Acrylic 1: MMA/PMI/MADA copolymer (60/20/20 mass ratio), Mw: 1.5 million, Tg: 137°C (Also, the abbreviations are as follows. MMA: methyl methacrylate, PMI: phenyl maleic acid Imide, and MADA: adamantyl acrylate) 20 parts by mass Rubber particles R1 80 parts by mass Dispersant (polyoxyethylene lauryl ether sodium phosphate: molecular weight 332) Add an amount such that it becomes 0.006% by mass in the optical film

(Production of optical film 1) After coating the solution for optical film 1 on the peeling layer of the support using a die using a back coating method, the optical film was dried according to the following drying steps to form an optical film with a thickness of 5 μm, thereby obtaining optical film 1.

(Initial drying) Step 1: 1 minute at 40°C Step 2: 1 minute at 70°C Step 3: 1 minute at 100°C Step 4: 2 minutes at 130°C (post drying) Step 5: 15 minutes at 110°C

＜Preparation of rubber particles R1＞ Core-shell rubber particles prepared by the following method were used.

Into an 8L polymerization apparatus equipped with a mixer, the following materials were put.

Deionized water 180 parts by mass Polyoxyethylene lauryl ether phosphate 0.002 parts by mass Boric acid 0.473 parts by mass Sodium carbonate 0.047 parts by mass Sodium hydroxide 0.008 parts by mass

After the inside of the polymerization machine was sufficiently replaced with nitrogen, the internal temperature was adjusted to 80° C., and 0.021 parts by mass of potassium persulfate was added as a 2 mass % aqueous solution. Next, a monomer composed of 84.6 mass% methyl methacrylate, 5.9 mass% butyl acrylate, 7.9 mass% styrene, 0.5 mass% allyl methacrylate, and 1.1 mass% n-octylmercaptan was added. A mixture of 21 parts by mass of the mixture (c') and 0.07 parts by mass of polyoxyethylene lauryl ether phosphate was added continuously to the above solution over 63 minutes. Furthermore, by continuing the polymerization reaction for 60 minutes, the innermost hard polymer (c) was obtained.

Then, 0.021 parts by mass of sodium hydroxide was added as a 2% by mass aqueous solution, and 0.062 parts by mass of potassium persulfate was added as a 2% by mass aqueous solution. Next, polyoxyethylene lauryl ether phosphate was added to 39 parts by mass of the monomer mixture (a') consisting of 80.0 mass% butyl acrylate, 18.5 mass% styrene, and 1.5 mass% allyl methacrylate. 0.25 parts by mass of the mixed liquid was added continuously over 117 minutes. After the addition, 0.012 parts by mass of potassium persulfate was added as a 2 mass % aqueous solution, and the polymerization reaction was continued for 120 minutes to obtain a soft layer (a layer made of the acrylic rubber-like polymer (a)). The glass transition temperature (Tg) of the soft layer is -30°C. The glass transition temperature of the soft layer is calculated by averaging the glass transition temperatures of the homopolymers of each monomer constituting the acrylic rubber-like polymer (a) according to the composition ratio.

Then, 0.04 parts by mass of potassium persulfate was added as a 2% by mass aqueous solution, and 26.1 parts by mass of the monomer mixture (b') composed of 97.5% by mass of methyl methacrylate and 2.5% by mass of butyl acrylate was continuously added for 78 minutes. Add to. The polymerization reaction was continued for 30 minutes to obtain polymer (b).

The obtained polymer (b) was put into a 3 mass% sodium sulfate warm aqueous solution to salt out and solidify. Next, dehydration and washing were repeated and then dried, thereby obtaining acrylic graft copolymer particles (rubber particles R1) with a three-layer structure. The average particle diameter of the obtained rubber particles R1 was 200 nm.

The average particle size of rubber particles is measured by the following method.

(average particle size) The dispersed particle size of the rubber particles in the obtained dispersion was measured using a zeta potential/particle size measuring system (ELSZ-2000ZS manufactured by Otsuka Electronics Co., Ltd.).

＜Production of Optical Film 2~7＞ Optical films 2 to 7 were produced in the same manner except that the thickness of the optical film 1 was changed as shown in Table II.

＜Production of Optical Film 8~11＞ In the production of optical film 1, optical films 8 to 11 were produced in the same manner except that the content ratios of acrylic acid 1 and rubber particles R1 were changed to 60:40, 80:20, 15:85 and 10:90 respectively.

＜Production of optical film 12＞ (support body) As a support, a polyethylene terephthalate film (PET film) was used: (TN100 manufactured by Toyobo Co., Ltd., release layer containing a non-polysilicone release agent, thickness 38 μm).

(Preparation of solution for optical film 12) The following components were mixed to obtain a solution for optical film 12.

Dichloromethane (boiling point 41°C): 860 parts by mass Methanol (boiling point 65°C): 40 parts by mass COP1 (G7810: ARTON (registered trademark) G7810 manufactured by JSR Co., Ltd., Mw: 140,000, cycloolefin resin with carboxylic acid group) 100 parts by mass Antioxidant (Irganox (registered trademark) 1076; manufactured by BASF: molecular weight 531) Add an amount such that it becomes 0.002% by mass in the optical film.

(Production of optical film 12) After coating the solution for optical film 12 on the peeling layer of the support using a die using a back coating method, the optical film was dried according to the following drying steps to form an optical film with a thickness of 5 μm, thereby obtaining optical film 12.

Step 1: 1 minute at 40°C Step 2: 1 minute at 70°C Step 3: 1 minute at 100°C Step 4: 2 minutes at 130°C

＜Production of Optical Film 13~16＞ Optical films 13 to 16 were produced in the same manner except that the thickness of the optical film 12 was changed as shown in Table II.

＜Production of optical film 17＞ (support body) As a support, a polyethylene terephthalate film (PET film) was used: (TN100 manufactured by Toyobo Co., Ltd., release layer containing a non-polysilicone release agent, thickness 38 μm). (Preparation of solution for optical film 17) Dichloromethane (boiling point 41°C): 860 parts by mass Methanol (boiling point 65°C): 40 parts by mass TAC: 100 parts by mass of acetyl cellulose with an acetyl substitution degree of 2.9 Antioxidant (Irganox 1076; manufactured by BASF: molecular weight 531) Add an amount such that it becomes 0.002% by mass in the optical film. (Production of optical film 17) The solution for optical film 17 was coated on the peeling layer of the support by a back coating method using a die, and then the optical film was dried according to the following drying steps to form an optical film with a thickness of 5 μm, thereby obtaining optical film 17.

Step 1: 1 minute at 40°C Step 2: 1 minute at 70°C Step 3: 1 minute at 100°C Step 4: 2 minutes at 130°C

＜Production of Optical Film 18＞ (support body) As a support, a polyethylene terephthalate film (PET film) was used: (TN100 manufactured by Toyobo Co., Ltd., release layer containing a non-polysilicone release agent, thickness 38 μm).

(Preparation of polyimide 1) In a four-necked flask equipped with a dry nitrogen inlet pipe, a cooler, a Dean-Stark condenser filled with toluene, and a stirrer, add 5.146g (20mmol) of MeO-DABA represented by the following formula , add 20 mL of γ-butyrolactone (GBL) and 10 mL of toluene, and stir at room temperature under nitrogen flow.

Thereto, 4.483 g (20 mmol) of 1,2,4,5-cyclohexanetetracarboxylic dianhydride (H-PMDA) powder was added, and the mixture was heated and stirred at 80° C. for 6 hours. Then, it was heated to an external temperature of 190° C., and the water generated along with the imidization was azeotropically distilled off together with toluene. Heating and refluxing for 6 hours. When stirring was continued, water was no longer produced. Then, the mixture was heated for 7 hours while toluene was distilled off. After the toluene was distilled off, methanol was added to perform reprecipitation to obtain 6.4 g of polyimide powder (yield: 72%).

(Preparation of solution for optical film 18) Dichloromethane (boiling point 41°C): 900 parts by mass Polyimide 1 (the above-mentioned polyimide powder): 100 parts by mass

(Production of optical film 18) After coating the solution for optical film 18 on the peeling layer of the support using a die using a back coating method, the optical film was dried according to the following drying steps to form an optical film with a thickness of 5 μm, thereby obtaining optical film 18.

(Initial drying) Step 1: 1 minute at 40°C Step 2: 1 minute at 70°C Step 3: 1 minute at 100°C Step 4: 2 minutes at 130°C (post drying) Step 5: 15 minutes at 110°C

＜Production of Optical Film 19＞ (support body) As a support, a polyethylene terephthalate film (PET film) was used: (TN100 manufactured by Toyobo Co., Ltd., release layer containing a non-polysilicone release agent, thickness 38 μm). (Preparation of solution for optical film 19) Dichloromethane (boiling point 41°C): 860 parts by mass Methanol (boiling point 65°C): 40 parts by mass Polyarylate (U-100: manufactured by UNITIKA Co., Ltd.): 100 parts by mass Antioxidant (Irganox 1076; manufactured by BASF: molecular weight 531) Add an amount such that it becomes 0.002% by mass in the optical film. (Production of optical film 19) After coating the solution for optical film 19 on the peeling layer of the support using a die using a back coating method, the optical film was dried according to the following drying steps to form an optical film with a thickness of 5 μm, thereby obtaining optical film 19.

Step 1: 1 minute at 40°C Step 2: 1 minute at 70°C Step 3: 1 minute at 100°C Step 4: 2 minutes at 130°C

[Formation of adhesive layer] ＜Preparation of adhesive films 1~11＞ (Synthesis of acrylic copolymers A~E) In a reaction device equipped with a stirrer, a thermometer, a reflux cooler, and a nitrogen inlet pipe, nitrogen gas was sealed, and 160 parts by mass of ethyl acetate and 10 parts by mass of acetone were used as reaction solvents. OA), lauryl acrylate (LA), acrylic acid, A-LEN-10 (acrylic acid, ethoxylated-o-phenylphenol acrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.), phenoxyethyl acrylate (PHEA) or less To the monomer composition mixed at the mass ratio shown in Table I, 0.1 part by mass of azobisisobutyronitrile (ABN-R) was added as a polymerization initiator. Then, while stirring these, they were reacted at 61°C for 7 hours in a nitrogen gas flow to obtain acrylic copolymers A to E.

(Preparation of acrylic copolymer solutions A~E) After the reaction, 0.1 parts by mass of Irganox (registered trademark) B-215 (trade name, manufactured by BASF) was added as an antioxidant, and ethyl acetate was added as a dilution solvent to dilute, thereby preparing an acrylic copolymer with a solid content of 18.2%. Solutions A~E. The weight average molecular weight of the synthesized copolymers is approximately 1.5 million.

Note: The values in Table I express the amount of material compounds added in terms of mass ratio.

(Preparation of coating liquids A~E for forming adhesive films) To 100 parts by mass each of the acrylic copolymer solutions A to E, 0.3 parts by mass of Coronate L (trade name, manufactured by Tosoh Corporation) as an isocyanate-based hardener and an epoxy terminal coupling agent as a silane coupling agent were blended. (KBM-403, manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0.2 parts by mass to obtain coating liquids A to E for forming adhesive films.

(Preparation of adhesive film 1) On a peel-treated polyethylene terephthalate film (PET film) as a release film, the coating liquid D for forming an adhesive film is degassed, applied with a doctor blade, and dried at 90°C. In 3 minutes, an adhesive film with a thickness of 15 μm was formed, and adhesive film 1 was obtained.

(Preparation of Adhesive Film 2~7) In the production of adhesive film 1, except that the thickness is changed as shown in Table II, adhesive films 2 to 7 are produced in the same manner.

(Production of adhesive film 8~11) In the preparation of the adhesive film 1, except that the material of the coating liquid for forming the adhesive film is changed as shown in Table II, the adhesive films 8 to 11 are produced in the same manner.

[Production of laminated film] ＜Preparation of laminated film 101＞ On the surface of the above-mentioned adhesive film 1 opposite to the surface in contact with the polyethylene terephthalate film, the above-mentioned optical film 1 is bonded, and left to stand for 7 days in an environment of 23°C and 50% RH. After aging, the laminated film 101 is obtained.

＜Preparation of laminated films 102~129＞ In the production of the laminated film 101, the optical film and the adhesive film are combined as shown in Table II to produce the laminated films 102 to 129.

≪Evaluation≫ [Evaluation of optical films] <Thickness shown in Formula 1: Flatness> It was measured whether the produced optical film satisfies the thickness range represented by the following formula 1 of the present invention. Formula 1: 5＜｜The average value of the thickness of three randomly selected points in the width direction (B) - average film thickness value (A) |/average film thickness value (A) × 100＜20 (%) Here, the average film thickness value (A) is the average value of film thickness values at 10 points arbitrarily extracted from the film. The film thickness was measured using F20-UV (manufactured by FILMETRICS) as a film thickness measurement system. For the value represented by the average value (B) of the thickness of three arbitrarily selected points in the width direction in Formula 1 - average film thickness value (A) | / average film thickness value (A) × 100 (%), perform Evaluation. ◎：More than 8%~less than 17% ○: More than 5% and less than 8%, or more than 17% and less than 20% ×: less than 5%, or more than 20%

＜Water vapor transmittance of optical films＞ The produced optical film was peeled off from the support and measured according to the "moisture permeability test method calcium chloride-cup method" described in JIS Z-0208:1976, leaving it at 40°C and 90%RH for 24 hours. .

[Evaluation of adhesive layer] ＜Adhesion＞ Cut the produced laminated film into a size of 70mm x 25mm, peel off the release film, and use a 2kg roller to connect the adhesive layer to the glass plate with a thickness of 2mm at 23°C and 50% RH. Leave under conditions for 2 hours. Then, the laminated film was stretched in a direction of 90° with respect to the glass plate surface at a speed of 300 mm/min, and the adhesive force was measured.

＜Water vapor transmission rate of adhesive layer＞ In the same manner as the method described in "Method for Manufacturing Adhesive Layer", an adhesive layer is formed on the release film, and a nonwoven fabric is bonded to it. Then, the release film is peeled off and the non-woven fabric is bonded so that the non-woven fabric is bonded to both sides of the adhesive layer. Using this sheet, measurement was carried out by leaving it to stand for 24 hours under the conditions of 40°C and 90% RH in accordance with the "Moisture Permeability Test Method Calcium Chloride-Cup Method" described in JIS Z-0208:1976.

The following Table II shows the composition and evaluation of the optical film and adhesive layer.

The obtained laminated film was evaluated as follows as a laminated body bonded to a glass plate.

≪Evaluation≫ ＜Impact resistance＞ (Preparation of laminated body samples) The single surface of a glass plate (G-Leaf, OA-10G manufactured by Nippon Electric Glass Co., Ltd.) with a width of 100 mm, a length of 120 mm, and a thickness of 30 μm was washed with methyl ethyl ketone, corona treated, and then coated with epoxy terminals. The coupling agent (KBM-403, manufactured by Shin-Etsu Chemical Industry Co., Ltd.) was heat-treated at 110° C. for 5 minutes. On the surface of the coupled-treated glass plate, peel off the release film from the laminated films 101 to 129 produced above, and attach the adhesive layer to the glass plate to prepare laminated body samples 201 to 229. Evaluation below. The evaluation results are summarized and shown in Table III below.

The above-mentioned laminated body samples were placed on two tables with a height of 10 mm installed on the table. At this time, the laminated body sample was placed on the above-mentioned stage from both ends in the longitudinal direction to a 10 mm portion with the optical film side facing upward (in the direction opposite to the above-mentioned stage and not in contact). That is, it is arrange|positioned so that the area|region of a central part (100mmx100mm) may become a floating state. An iron ball (weight: 500g, diameter: 50mm) is dropped from a position 20cm above the area. After visually confirming the state of the laminated body, anything before ○ is regarded as passing. ◎: The test will be carried out 10 times and no glass plate will fly even once. ○: The case where the glass plate is scattered less than 2 times after 10 times of implementation. ×: When the operation is carried out 10 times and the glass plate is scattered more than 3 times

＜Durability (heat and moisture resistance)＞ (Preparation of laminated body samples) Peel off the release film from the above-mentioned laminated film cut into a width of 150mm and a length of 250mm, and use a lamination roller to laminate one side of the glass plate with a thickness of 0.05mm in such a way that the adhesive layer is connected to the glass plate. Prepare a laminated body sample. Keep it in an autoclave adjusted to 50°C/5 atmospheres for 20 minutes, and then place it for 500 hours at a temperature of 60°C/humidity 90%RH (humidity and heat resistance).

For the laminated body sample, the occurrence of foaming, doming, and peeling was observed and evaluated based on the following standards, and any result with ○ was regarded as passing. ◎: No appearance defects such as foaming, doming, or peeling were observed. ○: Some appearance defects such as foaming, doming, and peeling are observed. ×: Poor appearance such as foaming, doming, and peeling is clearly observed

(Example 2) ≪Production of polarizing plate (liquid crystal polarizing sub-layer)≫ <Modulation of the composition for forming the polarizing sub-layer> The following components were mixed and stirred at 80° C. for 1 hour to obtain a polarizing sublayer forming composition. Among the dichroic dyes, the azo dye described in the Examples of Japanese Patent Application Laid-Open No. 2013-101328 was used.

[Polymerizable liquid crystal compound] (A'-6) 90 parts by mass

(A'-7) 10 parts by mass

(Dichroic pigment) azo pigments;

(Dichroic Pigment A) 2.5 parts by mass

(Dichroic Pigment B) 2.5 parts by mass

(Dichroic Pigment C) 2.5 parts by mass

[Polymerization initiator] 2-Dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure 369; manufactured by CIBA Specialty Chemicals Co., Ltd.) 6 parts by mass

[Leveling agent] Polyacrylate compound (BYK-361N; manufactured by BYK-Chemie Co., Ltd.) 1.2 parts by mass

[Solvent] Ortho-xylene 400 parts by mass

＜Formation of optical liquid crystal alignment layer on laminated film＞ (Preparation of composition for forming optical liquid crystal alignment layer) The composition for forming an optical liquid crystal alignment layer was obtained by mixing the following components described in Japanese Patent Application Laid-Open No. 2013-033249 and stirring the resulting mixture at 80° C. for 1 hour.

[Photo-alignment polymer]

2 parts by mass

[Solvent] o-xylene 98 parts by mass

＜Preparation of optical film with optical liquid crystal alignment layer＞ Using the laminated films 101 to 129 prepared above, the surface of the optical film layer exposed by peeling off the polyethylene terephthalate film (equivalent to the support 4) is subjected to corona treatment, and then the above-mentioned optical liquid crystal alignment is applied The layer-forming composition was dried at 120° C. to obtain a dry film. The dry film was irradiated with polarized UV to form an optical liquid crystal alignment layer, and a thin film with an optical liquid crystal alignment layer was obtained. The polarized UV treatment was performed using a UV irradiation device (SPOT CURE SP-7 manufactured by USHIO Electric Co., Ltd.) under the condition that the intensity measured at a wavelength of 365 nm was 100 mJ.

＜Preparation of polarizing sub-layer＞ On the laminated film with the optical liquid crystal alignment layer obtained as mentioned above, the above-mentioned polarizing sub-layer forming composition is coated by the rod coating method (#9 30mm/s), and dried by heating in a drying oven at 120°C After the polymerizable liquid crystal compound is phase-transferred to the liquid phase for 1 minute, the polymerizable liquid crystal compound is cooled to room temperature to phase-transfer to the smectic liquid crystal state.

Next, a UV irradiation device (SPOT CURE SP-7 manufactured by USHIO Denki Co., Ltd.) was used to irradiate the layer formed of the polarizing film forming composition with ultraviolet rays with an exposure amount of 1000 mJ/cm ² (365 nm standard). The polymerizable liquid crystal compound contained in the dry film is polymerized while maintaining the smectic liquid crystal state of the polymerizable liquid crystal compound, and a polarizing sub-layer is formed from the dry film. The thickness of the polarizing sublayer at this time was measured with a laser microscope (OLS3000 manufactured by OLYMPUS Co., Ltd.) and found to be 2.3 μm.

The obtained polarizing plate was subjected to X-ray diffraction measurement by irradiating X-rays from the absorption axis direction of the polarizing plate using an X-ray diffraction device X'Pert PRO MPD (manufactured by SPECTRIS Co., Ltd.). The result was 2θ=20.2°. A sharp diffraction peak (Bragg peak) with peak half-valency width (FWHM) = about 0.17° is obtained nearby. The order period (d) calculated from the peak position is approximately 4.4Å, confirming the formation of a structure reflecting a high-order smectic phase.

＜Formation of barrier layer＞ (Preparation of curable composition for barrier layer (1) formation) The following components were mixed to prepare a curable composition for forming the barrier layer (1). In addition, the mass part of "Sumirez Resin 650" represents the mass of solid content.

Pure water 100 parts by mass Polyvinyl alcohol film (manufactured by KURARAY Co., Ltd., "Kuraray Poval KL318" (trade name): carboxyl modified polyvinyl alcohol) 3 parts by mass Water-soluble polyamide epoxy resin (manufactured by Sumika CHEMTEX Co., Ltd., "Sumirez (registered trademark) Resin 650" (trade name), use solution with a solid content concentration of 30%)                                                 1.5 parts by mass

After corona treatment is applied to the surface of the polarizing sublayer of the polarizing plate produced above, a bar coater is used to apply the curable composition for forming the barrier layer (1) so that the thickness after curing becomes about 0.5 μm. Next, it was dried at 100°C for 1.5 minutes.

(Preparation of curable composition for barrier layer (2) formation) The following components are mixed to prepare a curable composition for forming the barrier layer (2).

Alicyclic epoxy compound Celloxide (registered trademark) 2021P (manufactured by DAICEL Chemical Co., Ltd.) 32.5 parts by mass EHPE3150 (made by DAICEL Chemical Co., Ltd.) 17.5 parts by mass Oxetane compound OXT221 (manufactured by Toagosei Co., Ltd.) 50 parts by mass Polymerization initiator CPI-100P (manufactured by SURFLON Co., Ltd.) 2.5 parts by mass Leveling agent SH710 (manufactured by Toray-Dow Corning Co., Ltd.) 0.25 parts by mass

Furthermore, after subjecting the surface of the barrier layer (1) to corona treatment, a bar coater is used to apply the curable composition for forming the barrier layer (2) so that the thickness after curing becomes about 1.5 μm. Next, a UV irradiation device (SPOTCURE P-7; manufactured by USHIO Electric Co., Ltd.) was used to irradiate the cured composition for forming the barrier layer (2) with ultraviolet rays with an exposure dose of 500 mJ/cm ² (365 nm standard). The formed layer is hardened to form a barrier layer, thereby obtaining polarizing plates 301 to 329.

≪Production of polarizing plate (iodine-PVA polarizing sub-layer)≫ ＜Preparation of polarizing sub-layer＞ A polyvinyl alcohol-based film with a thickness of 25 μm was swollen with 35° C. water. The obtained film was immersed in an aqueous solution composed of 0.075g of iodine, 5g of potassium iodide and 100g of water for 60 seconds, and further immersed in a 45°C aqueous solution of 3g of potassium iodide, 7.5g of boric acid and 100g of water. The obtained film was subjected to one-axis stretching at a stretching temperature of 55°C and a stretching magnification of 5 times. After washing the uniaxially stretched film with water, it was dried to form a polarizing sub-layer with a thickness of 12 μm.

<Preparation of ultraviolet curable adhesive composition> After mixing the following components, defoaming is performed to prepare an ultraviolet curable adhesive composition. 3,4-Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate 45 parts by mass Epolead (registered trademark) GT-301 (alicyclic epoxy resin manufactured by DAICEL) 40 parts by mass 1,4-Butanediol Diepoxypropyl Ether 15 parts by mass Triarylsonium hexafluorophosphate (solid content) 2.3 parts by mass 9,10-dibutoxyanthracene 0.1 parts by mass 1,4-diethoxynaphthalene 2.0 parts by mass Furthermore, the triarylsonium hexafluorophosphate system was blended as a 50% propyl carbonate solution.

＜Production of Polarizing Plate＞ Using the laminated film 104 prepared above, the surface of the optical film layer exposed by peeling off the polyethylene terephthalate film (equivalent to the support 4) was subjected to a corona output intensity of 2.0 kW and a linear speed of 18 m/min. Apply corona discharge treatment respectively. Similarly, triacetyl cellulose (thickness 25 μm) was prepared as a polarized photon protective layer, and its surface was subjected to corona treatment under the same conditions as above.

Then, the laminated film 104 is bonded to one side of the polarizer sub-layer produced above through an ultraviolet curable adhesive layer with a thickness of 1.5 μm, and the polarizer protective layer is bonded to the other side through an ultraviolet curable adhesive layer with a thickness of 1.5 μm. , making polarizing plates. The absorption axis of the polarizing sub-layer and the slow axis of the polarizing sub-layer are orthogonal to each other. Furthermore, the ultraviolet curable adhesive layer is formed using the above-mentioned ultraviolet curable adhesive composition.

Next, the obtained polarizing plate was irradiated with ultraviolet rays using an ultraviolet irradiation device equipped with a belt conveyor (the lamp system used a D bulb manufactured by Fusion UV Systems) so that the cumulative light intensity became 750 mJ/cm ² to thereby cure the ultraviolet rays. The adhesive layer is cured to obtain the polarizing plate 330.

The following evaluations were performed on the obtained polarizing plates 301 to 330.

≪Evaluation≫ (Production of polarizing plate sample with glass plate) After cleaning the single surface of a glass plate (Dynorex UTG manufactured by Nippon Electric Glass Co., Ltd.) with a width of 100 mm, a length of 120 mm, and a thickness of 30 μm with methyl ethyl ketone, corona treatment was performed, and then an epoxy terminal coupling agent (KBM) was applied -403, manufactured by Shin-Etsu Chemical Industry Co., Ltd.), heat treated at 110°C for 5 minutes. On the surface of the coupled glass plate, peel off the release film from the polarizing plates 301 to 330 produced above, and attach the adhesive layer to the glass plate to prepare a polarizing plate sample with the glass plate. 401 to 430, the following evaluation was performed, and the same results were obtained as for the laminate laminated to the glass plate.

＜Optical unevenness after folding endurance test＞ The folding endurance test was performed using a 180° folding endurance testing machine (manufactured by Imoto Seisakusho). This device is a mechanism that clamps a mandrel in a constant temperature bath and bends the chuck on one side repeatedly 180°. The bending radius can be changed by the diameter of the mandrel. It is a mechanism that stops the test if the film breaks. The test was carried out by placing the above-mentioned laminated body sample in a device with the glass plate as the concave side (inside) and the optical film as the convex side (outside). After leaving it at a temperature of 25°C for 24 hours, the sample was tested at a bending angle of 180° and a bending radius of 180°. The evaluation was carried out under the conditions of 3mm, bending speed of 1 second/time, and weight of 100g. After the number of bends reaches 200,000 times, the following test is performed on the laminated body sample after the bending endurance test including the bending part.

The laminated body sample after the above-mentioned folding resistance test was sandwiched between two test polarizing plates in the crossed Nicols state, and the cross Nicols were shifted under transmitted light until the light passed through, and the intensity of the transmitted light was visually observed. For shades, ○ or above will be regarded as passing. The evaluation results are shown in Table III below. ◎: The shade of transmitted light cannot be seen ○: Only the shade of transmitted light is slightly visible ×: See the intensity of transmitted light

It can be seen from the evaluation results in Table III that the laminated film of the present invention has excellent impact resistance and bonding durability under high temperature and high humidity when bonded to a glass plate. In addition, the polarizing plate of the present invention has excellent repeatability when bonded to a glass plate. It has excellent folding action durability and no optical unevenness.

The liquid crystal display device including the polarizing plate produced as described above was produced as follows. That is, a liquid crystal TV Wooo W32-L7000 manufactured by Hitachi which is a horizontal electric field mode liquid crystal display device was prepared. The liquid crystal cell contained therein has two substrates and a liquid crystal layer arranged between them. It is an IPS type in which only one of the two substrates is equipped with a pixel electrode and a counter electrode. In addition, the liquid crystal cell is arranged so that the substrate on which the pixel electrode and the counter electrode are arranged becomes the backlight side.

Then, peel off the pre-attached backlight side polarizing plate of Hitachi LCD TV Wooo W32-L7000, and attach it to the adhesive layer of the polarizing plate produced above and the glass surface of the liquid crystal cell. The adhesive layers of the above-produced polarizing plates 301 to 330 are bonded to the liquid crystal cells in such a manner that the absorption axis of the above-mentioned polarizing plates and the absorption axis of the pre-laminated polarizing plates are in the same direction. The "Egg unevenness" (circular unevenness) of the obtained liquid crystal display device was evaluated by leaving the obtained liquid crystal display device in a chamber of 50° C. and 80% RH for 72 hours. Then, the liquid crystal display device was taken out from the chamber, and the difference (image unevenness) between the brightness near the four vertices of the display screen and the brightness near the center of the display screen was visually observed with the liquid crystal display device in a black display state at normal temperature. Comparative Example In a display device with a polarizing plate, image unevenness is seen at two or more of the four vertices. On the other hand, a display device equipped with the polarizing plate of the present invention has no image unevenness at all, or if one pays careful attention, The degree of image unevenness is slightly visible and good results are obtained. [Industrial utilization possibility]

The laminated film of the present invention has excellent impact resistance and bonding durability under high temperature and high humidity when bonded to a flexible thin glass plate, and has excellent durability against repeated folding operations and no optical unevenness. By applying it to a foldable flexible display, a high-performance and highly durable flexible display can be provided.

1: Optical film 2:Adhesive layer 3: Release film 4:Support 11:Glass plate 21: Polarized sub-layer 22: Liquid crystal alignment layer 23: Phase difference film 24: Next layer 25: Polymerizable liquid crystal compound containing layer 26:Support 27: Barrier layer 28: Polarized photon protective layer 50:Laminated film 60:Laminated body 70:Polarizing plate 80: Polarizing plate with glass plate attached 90:Display R: bending radius B110:Support B200: Manufacturing equipment B210: Supply Department B220: Coating Department B230:Drying Department B240: Cooling section B250: Coiling section

[Fig. 1A] shows the basic layer structure of the laminated film of the present invention. [Fig. 1B] shows the basic layer structure of the laminated film of the present invention. FIG. 2 is a model diagram showing a method of manufacturing an optical film according to an embodiment of the present invention. [Fig. 3] shows the basic layer structure of the laminated body of the present invention. [Fig. 4A] shows the basic layer structure of the polarizing plate of the present invention. [Fig. 4B] shows the basic layer structure of the polarizing plate of the present invention. [Fig. 4C] shows the basic layer structure of the polarizing plate of the present invention. [Fig. 5A] shows the basic layer structure of a polarizing plate having a polarizing sub-layer according to one embodiment of the present invention. [Fig. 5B] shows the basic layer structure of a polarizing plate having a polarizing sub-layer according to an embodiment of the present invention. [Fig. 5C] shows the basic layer structure of a polarizing plate having a polarizing sub-layer according to an embodiment of the present invention. [Fig. 6] is a model diagram showing the manufacturing method of the polarizing plate roll material of the present invention. [Fig. 7] is a model diagram showing the manufacturing method of the polarizing plate roll with a glass plate according to the present invention. [Figure 8] is a model diagram of the display when it is folded.

1: Optical film

2:Adhesive layer

3: Release film

50:Laminated film

Claims (13)

A laminated film consisting of at least an optical film, an adhesive layer and a release film, characterized in that: the film thickness of the aforementioned optical film is 1 to less than 10 μm, and the film thickness of the aforementioned adhesive layer is 1 to 10 μm. Less than 10 μm, the film thickness of the aforementioned optical film satisfies the following formula 1; formula 1: 5<|average value of the thickness of three arbitrarily selected points in the width direction (B) - average film thickness value (A) |/average film Thickness value (A)×100<20. Such as the laminated film of claim 1, wherein the water vapor transmittance of the aforementioned optical film is in the range of 500~3000g/m ² ‧day at a temperature of 40°C and a humidity of 90%RH. The laminated film of claim 1 or 2, wherein the content of rubber particles in the optical film is in the range of 40 to 85% by mass relative to the optical film. The laminated film of claim 1 or 2, wherein the release film is peeled off and the adhesive force to the substrate is 3.0 N/25mm or more when the adhesive layer is bonded to the substrate. The laminated film of claim 1 or 2, wherein the aforementioned adhesive layer is for glass. For example, the laminated film of claim 1 or 2, wherein the water vapor transmission rate of the aforementioned adhesive layer is in the range of 800~5000g/m ² ‧day at a temperature of 40°C and a humidity of 90%RH. The laminated film of claim 1 or 2, wherein the water vapor transmittance of the adhesive layer is higher than the water vapor transmittance of the optical film. A laminated body characterized in that the laminated film and the glass plate according to any one of claims 1 to 7 are bonded through the aforementioned adhesive layer. A polarizing plate characterized by having the laminated film or laminated body according to any one of claims 1 to 8. A method of manufacturing a polarizing plate roll, which is a manufacturing method of a polarizing plate roll manufactured through the following steps: on the side of the aforementioned optical film of a laminated film composed of at least an optical film, an adhesive layer, and a release film, The laminating step of combining polarized photons to make a polarizing plate, and the winding step of winding the aforementioned polarizing plate; characterized in that: the film thickness of the aforementioned adhesive layer is 1 μm to less than 10 μm, and the film thickness of the optical film is 1 μm to less than 1 μm. up to 10μm. As claimed in claim 10, the method for manufacturing a polarizing plate roll is characterized in that the release film is not peeled off in the middle step but is rolled up. The method for manufacturing a polarizing plate roll according to claim 10 or 11, wherein the aforementioned polarizing plate roll is composed of at least the aforementioned release film, the aforementioned adhesive layer, the aforementioned optical film, and the aforementioned polarizer. A display device, characterized in that: the thickness of the substrate is in the range of 10 to 100 μm, and it is provided with the polarizing plate of claim 9.

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