TW202248015A - Optical film method for producing optical film and polarizer and display device using optical film - Google Patents

Abstract

The present invention addresses the problem of providing: an optical film in which adhesion between layers and light resistance are improved; a method for producing the optical film; and a polarizing plate and a display device provided with the optical film. The optical film according to the present invention is provided with a base film, a highly adhesive layer, and a hard coat layer in this order, the highly adhesive layer containing an aqueous polyolefin resin, the highly adhesive layer and the hard coat layer each containing a surface conditioning agent, the surface conditioning agent contained in the highly adhesive layer being a polyether-modified polysiloxane, and the hard coat layer containing a polyether-modified polysiloxane. The HLB value of the polyether-modified polysiloxane is within the range of 5-15, and the weight-average molecular weight of the surface conditioning agent contained in the hard coat layer is 4000 or less.

Description

Optical thin film, manufacturing method thereof, polarizing plate and display device having same

The present invention relates to an optical film and its manufacturing method, as well as a polarizing plate and a display device equipped with the same. More specifically, it relates to an optical film with improved interlayer adhesion and light resistance.

The technical development of liquid crystal display devices and organic EL display devices is progressing, and in recent years, display devices with high designability such as thin, soft and bendable flexible displays are being developed. Specifically, installation in a shape that wraps around a pillar in a public facility, or installation as a substitute display device for measuring equipment such as a tachometer mounted in a car is being considered.

The optical film included in the polarizing plate included in such a display device is a highly flexible film, and in consideration of the use environment of the display device, the utilization of a film excellent in heat resistance and moisture resistance is expected.

On the other hand, many display devices in recent years have the function of a touch panel directly touching the display with a finger or a pen, and require high scratch resistance. In addition, a display device mounted in a vehicle is required to have high shock resistance from the viewpoint of safety to the human body.

These functions can be imparted by forming a hard coat layer on the optical film. However, for example, a cycloolefin film has a weak bond with the hard coat layer because there are few chemical reaction sites. Therefore, a technique of providing an easily-adhesive layer having a sufficient thickness between the optical film and the hard coat layer is known. However, from the viewpoint of production, it is required to make the easily-adhesive layer thinner.

Patent Document 1 discloses a technology of an optical thin film, which is a relatively thin easy-adhesive layer and has sufficient adhesiveness at the same time. The easy-adhesive layer is characterized in that it contains a mixture of polyolefin-based resin and cellulose-based resin, but it is difficult to mix the resins uniformly, and storage is also difficult. In addition, the adhesiveness of the optical film in an environment exposed to light, that is, the light resistance is not sufficient.

Patent Document 2 discloses a technology of polysiloxane resin composition, which is characterized in that it contains polysiloxane containing hydroxyl, silane coupling agent containing epoxy group and silicon compound containing amino group, and it is recorded that Silicone oil such as polyether-modified silicone oil is used as a diluent. However, the so-called diluent is added for the purpose of adjusting the viscosity and flexibility of the resin composition, and the improvement of light resistance due to the addition of polyether-modified silicone oil has not been studied. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent No. 6453689 [Patent Document 2] Japanese Patent No. 5175818

[Problem to be Solved by the Invention]

The present invention was made in view of the above-mentioned problems and situations, and the problem to be solved is to provide an optical film having improved interlayer adhesion and light resistance, a manufacturing method thereof, a polarizing plate and a display device having the same. [Means used to solve problems]

In order to solve the above-mentioned problems, the inventors found that by selecting the resin for the easy-adhesive layer and the surface conditioner for the easy-adhesive layer and the hard coat layer during the process of examining the causes of the above-mentioned problems, it is possible to The present invention has been accomplished by providing an optical film having improved interlayer adhesion and light resistance, a method for producing the same, and a polarizing plate and a display device equipped with the same. That is, the above-mentioned problems of the present invention are solved by the following means.

1. An optical film, characterized in that it is an optical film with a substrate film, an easy-adhesive layer and a hard coat layer in sequence, wherein the aforementioned easily-adhesive layer contains a water-based polyolefin resin, and the aforementioned easily-adhesive layer and the aforementioned The hard coat layers each contain a surface regulator, and the aforementioned surface regulator contained in the aforementioned easy-adhesive layer is a polyether-modified polysiloxane, and the HLB value of the aforementioned polyether-modified polysiloxane is within the range of 5 to 15. The weight average molecular weight of the said surface modifier contained in the said hard-coat layer is 4000 or less.

2. The optical film according to item 1, wherein the base film contains a cycloolefin resin.

3. The optical film according to item 1 or 2, wherein the surface modifier contained in the easy-adhesive layer and the hard coat layer are the same compound.

4. The optical film as described in any one of items 1 to 3, wherein the mass of the aforementioned surface conditioner contained in the aforementioned easy-adhesive layer and the aforementioned hard coat layer is respectively set as Mp and In the case of Mh, the value of the content mass ratio (Mh/Mp) is within the range of 0.02-40.

5. A method for producing an optical film, characterized in that it is a method for producing an optical film as described in any one of items 1 to 4, wherein the above-mentioned substrate film includes A step of forming the aforementioned easy-adhesive layer, and a step of forming the aforementioned hard coat layer on the aforementioned easily-adhesive layer.

6. A polarizing plate, characterized in that it is equipped with an optical film as described in any one of items 1 to 4.

7. A display device, characterized in that it is equipped with a polarizing plate as described in Item 6. [Effect of Invention]

By the means of the present invention, it is possible to provide an optical film having improved interlayer adhesion and light resistance, a method for producing the same, and a polarizing plate and a display device having the same.

The expression mechanism or the action mechanism of the effect of the present invention is not yet clear, but it is inferred as follows.

In order to impart scratch resistance and impact resistance to the substrate film, a method of forming a hard coat layer is known. However, the method of directly forming a hard coat layer on the substrate film has a problem of adhesion between layers. Therefore, by forming the hard coat layer after forming the easy-adhesive layer on the base film, the adhesion between the base film and the hard coat layer is improved upward. However, if the obtained film is considered to be used in a display device, the adhesion between the layers exposed to light, that is, light resistance is necessary, but the adhesion between the easy-adhesive layer and the hard coat layer is necessary. Attachment is not enough.

As the adhesion mechanism between the easy-adhesive layer and the hard coat layer, it is considered that there is a chemical interaction (also called "chemical adsorption") caused by a bond generated by a chemical reaction, and, by molecular The physical interaction (also known as "physical adsorption") generated by inter-force. Specifically, in the resin contained in the easy-adhesive layer and the resin contained in the hard coat layer, the functional groups are bonded to each other and also attract each other due to intermolecular force. In the environment exposed to light, since the chemical bond is broken, the compound such as resin is oxidized and deteriorated, and it is considered that the chemical interaction is weakened, and the adhesive force is reduced.

Therefore, the inventors conceived whether high adhesion can be maintained if the physical interaction is sufficient to function even if the chemical interaction is reduced. More specifically, in order to enhance the intermolecular force between the easy-adhesive layer and the hard coat layer, the distance between the easy-adhesive layer and the hard coat layer is very close, that is, the resin used in the formation of the hard coat layer will Adding a highly compatible surface regulator to the easy-adhesive layer, and further adding a low molecular weight surface regulator to the hard coat layer, it was discovered that an optical film with improved interlayer adhesion and light resistance can be obtained.

The detailed mechanism of this performance is not yet clear, but it may be speculated as follows.

From the viewpoint of moldability, it is preferable to form the easy-adhesive layer by direct coating on the base film, but if the polyolefin resin used for the easy-adhesive layer is dissolved in an organic solvent and coated, the base film Cracks will occur. For this purpose, it can be formed by coating the easy-adhesive layer on the base film using a water-based polyolefin resin that is a water-based dispersion. However, the surface tension of water is comparatively large. If it is directly applied to the base film, it will cause sinking and poor wetting, making it difficult to form a layer with a uniform thickness.

The surface regulator added to the easy-adhesive layer of the present invention is polyether-modified polysiloxane, which can change the balance of the hydrophilic group and the hydrophobic group in the molecule by changing the structure of the side chain, and then can Control the polarity of compounds. The HLB value is the value indicating the balance between the hydrophilic group and the hydrophobic group in the molecule. If the HLB value is in the range of 5 to 15, the molecule will not be too coagulated or dispersed in water, and it can be easily adsorbed in water. Surface (interface between liquid and gas). Moreover, compatibility with the resin used for formation of a hard-coat layer can be improved by making HLB value into the said range.

Therefore, even in the easy-adhesive layer of the present invention containing a water-based polyolefin resin, the polyether-modified polysiloxane is easily adsorbed and aligned on the surface of the easily-adhesive layer, and even if the resin concentration becomes high during the drying process, it can still be Adsorption alignment continues. Comparatively speaking, the polyether-modified polysiloxane with low surface tension can form a layer of uniform thickness by uniformly adsorbing on the surface of the easy-adhesive layer, and can make the surface smoother. In addition, the polyether-modified polysiloxane is mixed with the resin used in the hard coat layer, especially the acrylate resin, so that the distance between the easy-adhesive layer and the hard coat layer can be sufficiently close.

With regard to the hard coat layer, also by adding a surface conditioner, a layer with a uniform thickness can be formed and the surface can be further smoothed. Also, from the viewpoint of formability, it is preferable to form by direct coating on the easily-adhesive layer.

However, in the process of coating and drying the composition for forming a hard coat layer on the easy-adhesive layer, if the polyether-modified polysiloxane is adsorbed and aligned on the surface of the hard coat layer at the interface between liquid and gas, it will automatically Easy to move on the surface of the adhesive layer. Therefore, the polyether can be modified by setting the weight average molecular weight of the surface modifier contained in the hard coat layer to 4000 or less, that is, by using a surface modifier with a relatively fast adsorption rate. Polysiloxane stops on the surface of the easy-adhesive layer to maintain high adhesion between the easy-adhesive layer and the hard coat layer.

The optical film of the present invention is characterized in that it is an optical film comprising a substrate film, an easy-bonding layer, and a hard coat layer in sequence, wherein the easy-bonding layer contains a water-based polyolefin resin, and the easy-bonding layer and the above-mentioned The hard coat layers each contain a surface regulator, and the aforementioned surface regulator contained in the aforementioned easy-adhesive layer is a polyether-modified polysiloxane, and the HLB value of the aforementioned polyether-modified polysiloxane is within the range of 5 to 15. The weight average molecular weight of the said surface modifier contained in the said hard-coat layer is 4000 or less. This feature is a common or corresponding technical feature of the following implementations.

As an embodiment of the present invention, it is more preferable that the base film contains a cycloolefin resin from the viewpoint of heat and humidity resistance.

From the viewpoint of adhesiveness, it is more preferable that the aforementioned surface conditioner contained in each of the aforementioned easily-adhesive layer and the aforementioned hard coat layer is the same compound.

From the viewpoint of appearance, when the mass of the aforementioned surface conditioner contained in the aforementioned easy-adhesive layer and the aforementioned hard coat layer is set as Mp and Mh respectively, the value of the content mass ratio (Mh/Mp) is in the range of 0.02 to 40 The range is better.

The manufacturing method of the optical film of the present invention includes the steps of forming the aforementioned easy-adhesive layer on the aforementioned substrate film and forming the aforementioned hard coat layer on the aforementioned easily-adhesive layer from the viewpoint that the layer can be formed by direct coating. Steps are better.

The optical film of the present invention can be suitably used for a polarizing plate and a display device including the polarizing plate.

Hereinafter, the present invention, its components, and forms and aspects for carrying out the present invention will be described in detail. In addition, in this invention, "-" is used in the meaning which includes the numerical value described before and after that as a lower limit and an upper limit.

<<1 Summary of the optical film of the present invention>> The optical film of the present invention is characterized in that it is an optical film comprising a substrate film, an easy-bonding layer, and a hard coat layer in sequence, wherein the easy-bonding layer contains a water-based polyolefin resin, and the easy-bonding layer and the above-mentioned The hard coat layers each contain a surface regulator, and the aforementioned surface regulator contained in the aforementioned easy-adhesive layer is a polyether-modified polysiloxane, and the HLB value of the aforementioned polyether-modified polysiloxane is within the range of 5 to 15. The weight average molecular weight of the said surface modifier contained in the said hard-coat layer is 4000 or less.

FIG. 1 shows an example of the basic structure related to the layer structure of the optical film 10 of the present invention. The optical film 10 of the present invention is between the hard coat layer 1 and the substrate film 3 and has an easy-adhesive layer 2 .

Hereinafter, the structure of the optical film of the present invention will be described in detail.

＜1.1 Easy adhesive layer＞ The easy-adhesive layer of the present invention is characterized in that it contains a water-based polyolefin resin, and further contains a surface regulator, and the surface regulator is a polyether-modified polysiloxane, and the polyether-modified polysiloxane The HLB value is in the range of 5-15.

In the present invention, the so-called "easy-adhesive layer" does not mean that the entire layer contributes to adhesion, but refers to a layer that can be given adhesive force by appropriate arbitrary additives and appropriate treatment. Also, in this specification, the "adhesion" between the easy-adhesive layer and the hard coat layer is also called "adhesion" because the distance between the layers is very short and the intermolecular force is strong.

The thickness of the easy-adhesive layer of the present invention is preferably in the range of 0.3 to 1 μm from the viewpoint of stability of initial adhesion.

＜1.1.1 Water-based polyolefin resin＞ The resin used in the easy-adhesive layer of the present invention is characterized in that it is a water-based polyolefin resin. The so-called "water-based polyolefin resin" refers to a modified polyolefin resin having anionic or cationic polar groups that enable it to be dispersed in an aqueous medium. Generally, polyolefin resins are non-polar and hydrophobic, so wettability (hydrophilicity) is low, and coating or bonding is difficult. However, polar groups are introduced into polyolefin resins and dispersed in water to make them liquid , which makes it easy to form.

As a method of improving the molding processability of polyolefin resin, there is a method of dissolving polyolefin resin in an organic solvent, but as shown in the production method described later, it is preferable to directly form the easy-adhesive layer on the base film. By this method, the base film is prone to cracks. However, since the easy-adhesive layer of the present invention uses a water-based polyolefin resin, the forming process is easy, and it can be directly formed on the base material without cracking.

In addition, water-based polyolefin resins have relatively few polar groups and strong hydrophobicity. Therefore, during the drying process when the easy-adhesive layer is formed, even if the resin concentration becomes higher, it is still difficult for the polyether-modified polysiloxane described later to be adsorbed on the resin. Resin is considered to be sustainable on the surface of the easy-adhesive layer for adsorption and alignment.

As water-based polyolefin resins, ethylene-propylene copolymers with polar groups, ethylene-vinyl acetate copolymers, polyethylene-based ionomers, ethylene-vinyl alcohol copolymers, ethylene-acrylic acid copolymers, and ethylene-vinyl chloride copolymers can be used. substances, etc., which can exist in the form of aqueous solutions, aqueous dispersions, and aqueous emulsions. Among them, ethylene-unsaturated carboxylic acid copolymers, ethylene-based ionomer resins, ethylene-acrylic acid copolymers, and ethylene-vinyl acetate copolymers are relatively intermolecularly bonded with metal ions such as sodium or zinc. good.

In particular, the water-based polyolefin resin of the present invention contains an olefin component and an unsaturated carboxylic acid component as copolymerization components, and the olefin component preferably contains propylene and olefins other than propylene. Olefins other than propylene preferably contain butene and do not contain ethylene. It is known that the mass ratio of propylene/olefins other than propylene is 60/40 to 80/20, which is preferable in terms of adhesiveness and the like.

The copolymerization form of each component of the water-based polyolefin resin is not particularly limited, and any of known polymerization methods such as random copolymerization, block copolymerization, and graft copolymerization can be used, depending on the degree of ease of polymerization See, random copolymerization or graft copolymerization is preferred.

The unsaturated carboxylic acid component is not particularly limited, but examples include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, itaconic anhydride, aconitic acid, aconitic anhydride, fumaric acid, and crotonic acid , citraconic acid, mesaconic acid, allyl succinic acid, etc. Among them, maleic anhydride is more preferable.

As the aqueous medium for dispersing the polyolefin resin, in addition to using water alone, for example, well-known media such as methanol, ethanol, isopropanol, n-propanol, methyl ethyl ketone, and dimethylformamide can also be used. Use a combination of organic solvents and water.

In addition, in order to facilitate dispersion of the polyolefin resin, a basic compound may be added. The basic compound is not particularly limited, but ammonia or an organic amine compound is preferred. Specific examples of the organic amine compound include ethylamine, propylamine, isopropylamine, 3-methoxypropylamine, diethylamine, dipropylamine, and the like, but are not limited thereto. The blending amount of the basic compound is preferably 0.5 to 10 times equivalent to the carboxyl groups in the polyolefin resin.

Specific examples of water-based polyolefin resins that can be used include SE-1010, SE-1013N, SE-1030N, SD-1010, TC-4010, and "Arrow base (registered trademark) series" manufactured by Unitika Corporation. TD-4010, manufactured by Toho Chemical Co., Ltd., trade name "HiTEC series" S3148, S3121, S8512, P-5060N, P-9018, manufactured by Mitsui Chemicals Co., Ltd., trade name "unistole (registered trademark) series" S-120, S- 75N, V100, H-200, H-300, EV210H, Mitsui Chemicals Co., Ltd. product name "chemipearl (registered trademark) series" XHP-400 Sumitomo Seika Co., Ltd. product name "Zaikthene (registered trademark) series" Zaikthene A. Zaikthene L, manufactured by Toyobo Co., Ltd., trade name "hardlen (registered trademark) series" NZ-1004, NZ-1005, NZ-1022, etc.

＜1.1.2 Surface Conditioning Agent for Adhesive Layer＞ The surface conditioner contained in the easy-adhesive layer of the present invention (also called "surface conditioner for easily-adhesive layer") is a polyether-modified polysiloxane, characterized in that the HLB of the polyether-modified polysiloxane The value is in the range of 5-15.

To increase the adhesion between the easy-bonding layer and the hard coating layer, that is, in order to enhance the intermolecular force between the easy-bonding layer and the hard coating layer, it is necessary to make the distance between the easy-bonding layer and the hard coating layer sufficiently close. That is, by making the easy-adhesive layer contain the surface regulator highly compatible with the resin used for formation of a hard-coat layer, adhesive force can be improved.

The so-called "surface conditioner" is added for the purpose of preventing defects on the surface of the coating film during and after coating. The so-called "surface conditioner for the easy-adhesive layer" in the present invention refers to a substance added for the purpose of imparting good wettability and uniformity to the coating film, and smoothness and sliding properties on the surface of the coating film. In order to obtain such an effect, it is necessary to make the surface tension of the coating liquid smaller than that of the object to be coated.

Therefore, as the surface conditioner for an easily bonded layer of the present invention, a compound having both a hydrophilic group and a hydrophobic group in the molecule is preferable. Such compounds exist on the surface of the coating film and cause a large change in the surface energy, which can cause a huge change in the physical properties of the coating film surface.

[Polyether Modified Polysiloxane] The surface conditioner for an easily bonded layer of the present invention is characterized in that it is a polyether-modified polysiloxane. Here, the term "polyether-modified polysiloxane" refers to a compound in which a polyoxyalkylene group is introduced into a part of the siloxane bond of the polysiloxane compound.

The so-called polysiloxane compound is a compound with siloxane bonds (Si-O-Si) in the main skeleton. It has high flexibility, and the whole molecular system forms a helical structure, and the side chains are easily aligned on the surface of the helical structure. By having an alkyl group such as a methyl group in the side chain, the intermolecular force can be reduced, and the surface tension can be reduced. Also, the main chain (main skeleton) is non-polar, and by adding a polar substituent to the side chain, an interface-active structure having a polar part and a non-polar part in the same molecule can be formed. In particular, by having polyoxyalkylene groups in the side chains, the polysiloxane system exhibits interfacial activity and adsorbs and aligns on the surface of the easy-adhesive layer.

In addition, since the polysiloxane compound does not exhibit polarity as a whole, but only a part of the molecule, during the drying process when the easy-adhesive layer is formed, even the resin for the easily-adhesive layer with few polar groups and strong hydrophobicity As the concentration becomes higher, the polysiloxane compound is still not adsorbed on the resin, and it is considered that it can continue to adsorb and align on the surface of the easy-adhesive layer.

The surface regulator for the easy-adhesive layer of the present invention is a polyether-modified polysiloxane, whereby the side chain can have moderate polarity and high compatibility with the resin can be obtained. Polyether-modified polysiloxane is a compound in which a polyoxyalkylene group is introduced into a part of the siloxane bond of a polysiloxane compound, and any polyoxyalkylene group can be used in which the polyoxyalkylene group is introduced into the side chain or terminal of the siloxane skeleton. However, it is preferable to use a compound in which a polyoxyalkylene group is introduced into a side chain. An example of a preferable general formula is shown below.

(In the formula, R1 represents _{a hydrogen} atom or an alkyl group. R2 and _R3 represent an alkyl group. m, n, x, and y represent an integer of 1 or more.)

As the polyether-modified polysiloxane used in the present invention, it is preferable to use polyether-modified polydimethylsiloxane ( _R3 is a methyl group), or polyether-modified polydimethylsiloxane A polyether-modified polymethylalkylsiloxane ( _R3 is a long-chain alkyl group) in which one or all of the dimethyl groups of the oxane is substituted with a long-chain alkyl group.

Specific examples include polydimethylsiloxane modified with polyethylene oxide, polypropylene oxide, polybutylene oxide or a mixture thereof. The surface tension and polarity of these polyether-modified polydimethylsiloxanes can be adjusted by appropriately changing the amount and mixing ratio of polyethylene oxide, polypropylene oxide, or polybutylene oxide.

Also, among the polyether-modified polydimethylsiloxanes having polyoxyalkylene in the side chain of polydimethylsiloxane, it is preferable that the structural part of polydimethylsiloxane is the same as polyoxyalkylene. The chain structure is a linear block copolymer with alternating repeating bonds.

Regarding the degree of polymerization in the general formula (1), m is preferably an integer of 1-4, n is preferably an integer of 1-100, and x and y are preferably integers of 1-1000.

Commercially available polyether-modified silicones can also be used, for example, BYK (registered trademark)-300, BYK-302, BYK-306, BYK-307, BYK-320 manufactured by BYK-Chemie Japan Co., Ltd. , BYK-325, BYK-330, BYK-331, BYK-333, BYK-337, BYK-344, BYK-375, BYK-377, BYK-378, BYK-3450, BYK-UV3500, BYK-UV3510, Shin-Etsu KF-945, KF-352A, KF-640, KF-351A, KF-354L, KF-6011, KF-6015, KF-6020 manufactured by Chemical Industry Co., Ltd. XIAMETER (registered trademark) OFX manufactured by Dow Toray Co., Ltd. -0193 Fluid et al.

Also, the dynamic viscosity of polyether-modified silicone at 25°C is preferably 40 mm ² /s or higher, more preferably 50 mm ² /s or higher, and still more preferably 60 mm ² from the same viewpoint as above. /s or more, and preferably not more than 1000 mm ² /s, more preferably not more than 900 mm ² /s, still more preferably not more than 800 mm ² /s. In addition, the dynamic viscosity system can be obtained by an Ubbelode type viscometer.

[HLB value] The so-called "HLB value" refers to a numerical value indicating the balance between hydrophilic groups and hydrophobic groups in a molecule. More specifically, those without a hydrophilic group were set at 0, those with only a hydrophilic group without a hydrophobic group were set at 20, and those with both a hydrophilic group and a hydrophobic group in one molecule were set at an intermediate value. In addition, the so-called "HLB" refers to the abbreviation of Hydrophile Lipophile Balance.

The HLB value of one compound can be obtained, for example, by the Griffin method represented by the following formula (1). However, the so-called hydrophilic portion refers to the aggregate of hydrophilic groups in the molecule. Formula (1) HLB value = 20 x the sum of the formula weight of the hydrophilic part / molecular weight

The characteristic of the HLB value of the polyether-modified polysiloxane of the present invention is within the range of 5-15. If the HLB value is less than 5, the polyether-modified polysiloxane in the easy-adhesive layer tends to condense on the polyolefin resin with high hydrophobicity because there are few hydrophilic parts and high hydrophobicity, and it is difficult to align and adsorb on the easy-adhesive layer. surface. Also, the aggregation system causes poor appearance. If the HLB value exceeds 15, it is easy to dissolve in the organic solvent used when forming the hard coat layer due to its high hydrophilicity, and it is difficult to align and adsorb on the surface of the easy-adhesive layer. Moreover, compatibility with the resin used for formation of a hard-coat layer can be improved by making HLB value into the said range.

The HLB value of the polyether-modified polysiloxane of the present invention can be adjusted by appropriately changing the structure of the polyoxyalkylene group.

Also, the HLB value is more preferably within the range of 5-15, and more preferably within the range of 8-12.

[content] The content per unit thickness of polyether-modified polysiloxane (solid content ratio) is preferably 1 to 6 mass %, more preferably 2 to 5 mass %, relative to the total mass per unit thickness of the easy-adhesive layer material . If the content of the polyether-modified polysiloxane is 1% by mass or more relative to the total mass per unit thickness of the material for the easy-adhesive layer, it can be closely aligned on the surface of the easily-adhesive layer, so the adhesion is excellent. Moreover, if it is 6 mass % or less, since the aggregation of a surface modifier can be suppressed, the appearance of the optical film as a whole when forming an easily-adhesive layer by coating is excellent.

Also, the content (solid content ratio) Mp of the polyether-modified polysiloxane which is a surface conditioner in the easily-adhesive layer is represented by the following formula (I). Formula (I): Mp=(thickness of the easy-adhesive layer × solid content ratio per unit thickness of the surface conditioner contained in the easy-adhesive layer)

Mp is preferably in the range of 0.3-6. When Mp is 0.3 or more, the difference in surface tension becomes small at the interface between the substrate film and the coating film when the composition for forming an easily-adhesive layer is applied to the substrate film, and sags are less likely to occur. In addition, when Mp is 6 or less, the surface conditioner is less likely to aggregate. Therefore, if Mp exists in the said range, the optical film with high transparency can be obtained. Mp is more preferably within the range of 0.5-4, and even more preferably within the range of 1-3.

＜1.1.3 Other additives＞ In the easy-adhesive layer of the present invention, in addition to the above-mentioned surface conditioner, any additives may be used as required. Specific examples of additives include photopolymerization initiators, thermal polymerization initiators, polymerization accelerators, viscosity modifiers, slip agents, dispersants, plasticizers, heat stabilizers, light stabilizers, slippery agents, etc. , antioxidants, ultraviolet absorbers, flame retardants, colorants, antistatic agents, compatibilizers, crosslinking agents, etc. The type and amount of additives used can be appropriately set according to the purpose. For example, the usage-amount of an additive is preferably 30 mass parts or less, More preferably, it is 20 mass parts or less with respect to 100 mass parts of total solid content in an easy-adhesive layer.

Moreover, in order to impart anti-blocking properties, arbitrary appropriate fine particles can be used. Specific examples of fine particles include "Seahostar series (registered trademark)" KE-P20 and KE-P30 manufactured by Nippon Shokubai Co., Ltd., developed product KE-W20, "epostar series (registered trademark)" MX100W, and the like. The particle size of the microparticles is preferably within the range of 50-500 nm, more preferably within the range of 100-300 nm. If it is within the above range, the transparency and anti-blocking property of the easy-adhesive layer can be taken into account.

＜1.1.4 Formation method of easy-adhesive layer＞ The easily-adhesive layer system of the present invention can be formed using the composition for forming an easily-adhesive layer. The composition for forming an easily adhesive layer may be, for example, a commercially available solution or dispersion, may be used by adding a solvent to a commercially available solution or dispersion, or may be used by dissolving or dispersing a solid component in a solvent.

In the present invention, the composition for forming an easily-adhesive layer is preferably a mixture of the above-mentioned water-based polyolefin resin, the above-mentioned surface conditioner for an easily-adhesive layer, the above-mentioned additives, and a solvent if necessary, by a conventionally known method. modulation. As the solvent, for example, water may be used alone, or a known organic solvent such as methanol, ethanol, isopropanol, n-propanol, methyl ethyl ketone, or dimethylformamide may be used in combination with water.

Next, the obtained composition for easily-adhesive layer formation is given to the base film mentioned later, specifically, it coats. As the coating method, known methods can be used, such as spin coating, blade coating, roll coating, bar coating, blade coating, die coating, gravure coating, etc. , A method of applying and drying to obtain a predetermined thickness.

The formation conditions of an easily-adhesive layer are, for example, as follows. The easy-adhesive layer-forming composition is coated on the substrate film, and is usually dried at 50-150° C., preferably 60-100° C., for 1-10 minutes, preferably 2-7 minutes, to form a coating film.

When coating on the substrate film, solvent modification, corona treatment, plasma treatment, etc. can also be performed on the surface of the substrate film as a preparatory treatment for improving wettability.

The total solid content concentration of the composition for forming an easily-adhesive layer can vary depending on the type, solubility, coating viscosity, wettability, and thickness after drying of the easily-adhesive layer-forming material. In order to obtain an easy-adhesive layer with high surface uniformity, the total solid content concentration is preferably 1-100 parts by mass, more preferably 1-50 parts by mass relative to 100 parts by mass of the solvent.

As the viscosity of the composition for forming an easily-adhesive layer, any appropriate viscosity can be adopted within the range that can be applied. The viscosity is preferably 1 to 50 mPa·sec, more preferably 2 to 10 mPa·sec, as a value measured at a shear rate of 1000 (1/s) at 23°C. Within the above range, an easily-adhesive layer excellent in surface uniformity can be formed.

The base film laminated with the easy-adhesive layer can also be stretched at any ratio as required. The extending direction may be any one of uniaxial directions such as a horizontal direction, a vertical direction, and an oblique direction with respect to the conveyance direction, or may be a biaxial direction. In addition, stretching of the base film may be performed before forming the easily-adhesive layer, after forming the easily-adhesive layer, etc. as necessary, and may be stretched one or more times each before forming the easily-adhesive layer and after forming the easily-adhesive layer. The extended conditions are the same as above.

＜1.2 Hard coating＞ The hard coat layer of the present invention is characterized in that it contains a surface modifier, and the weight average molecular weight of the surface modifier is 4000 or less. Due to the hard coating, it can provide an optical film with high scratch resistance and impact resistance.

The hard coat layer of the present invention preferably exhibits a hardness of "HB" or higher in the pencil hardness test specified in JISK5600-2014, and the thickness of the hard coat layer is determined by mechanical film strength such as scratch resistance and pencil hardness. From a viewpoint, it is preferably in the range of 0.5 to 4 μm, more preferably in the range of 1 to 3 μm.

＜1.2.1 Resin for hard coat＞ As the resin for the hard coat layer, it is preferable to use an active energy ray-curable resin that is hardened by irradiation of active energy rays from the viewpoint that it can be formed at room temperature in a short time. Such a resin is preferably a resin containing a monomer having an ethylenically unsaturated double bond. In addition, as the active energy rays, for example, ultraviolet rays or electron beams can be used, and ultraviolet rays are more preferable from the viewpoint of mechanical film strength (scratch resistance, shock resistance, and pencil hardness).

As the active energy ray curable resin, an acrylic material is preferably used. As acrylic materials, monofunctional or polyfunctional (meth)acrylate compounds such as (meth)acrylates of polyols, compounds synthesized from diisocyanates, polyols, and hydroxyl esters of (meth)acrylic acid can be used. Multifunctional urethane (meth)acrylate compound. In addition, polyether resins, polyester resins, epoxy resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyenes, etc. having acrylate functional groups can also be used. resin etc.

Among these resins, those cured by ultraviolet rays are more preferable. In particular, ultraviolet curable acrylate resins, ultraviolet curable urethane acrylate resins, and ultraviolet curable polyester acrylic resins are preferably used. There are ester resins, ultraviolet curable epoxy acrylate resins, ultraviolet curable polyalcohol acrylate resins, ultraviolet curable epoxy resins, and the like, among which ultraviolet curable acrylate resins are preferred.

The hard coat layer is formed, for example, using a composition for forming a hard coat layer containing an active energy ray curable resin, a polymerization initiator, and a solvent. The solvent contained in the composition for forming a hard coat layer is preferably a solvent that dissolves or swells the easily-adhesive layer. Thereby, the composition system for forming a hard-coat layer becomes easy to penetrate from the surface of an easily-adhesive layer to the inside, and the adhesiveness of an easily-adhesive layer and a hard-coat layer can be improved upwards.

＜1.2.2 Surface conditioner for hard coating＞ The surface conditioner contained in the hard coat layer of the present invention (also referred to as a surface conditioner for a hard coat layer.) is characterized in that its weight average molecular weight is 4000 or less. The so-called surface conditioner is the same as the above-mentioned surface conditioner for the easy-adhesive layer, which is added for the purpose of imparting good wettability and uniformity to the coating film, and smoothness and sliding properties on the surface of the coating film. As the compound that can be used, a compound having both a hydrophilic group and a hydrophobic group in the molecule is preferable.

The hard coat layer of the present invention is preferably formed directly on the easy-adhesive layer. More specifically, it is preferable to apply a composition for forming a hard coat layer on the easy-adhesive layer and harden it by irradiation with active energy rays. Therefore, from the viewpoint of increasing the adhesive force between the easily-adhesive layer and the hard-coat layer, it is preferable to form the easily-adhesive layer smoothly with a uniform thickness even in the hard-coat layer.

Also, if the composition for forming a hard coat layer is directly coated on the easily bonding layer, the surface of the easily bonding layer will no longer be a gas-liquid interface, so the polyether-modified polysiloxane originally adsorbed and aligned on the surface of the easily bonding layer, The surface state of the easy-adhesive layer changes due to the movement of the hard coating surface that absorbs a new gas-liquid interface.

The hard coat layer of the present invention can be formed smoothly with a uniform thickness due to the addition of a surface regulator with a weight average molecular weight of 4000 or less. In addition, compared with the surface regulator for an easy-adhesive layer, it is preferentially adsorbed and aligned on the surface of the hard coat layer. , it is possible to form a hard coat layer without changing the surface state of the easily-adhesive layer.

That is, by making the weight average molecular weight of the surface conditioner for a hard coat layer 4000 or less, making it relatively small, since the surface conditioner for a hard coat layer can be freely contained in the composition for forming a hard coat layer Therefore, it is easy to adsorb and align on the surface of the hard coating.

Therefore, since the surface conditioner for a hard coat layer has a weight average molecular weight of 4000 or less, it can preferentially adsorb and align on the surface of a hard coat layer compared with the surface conditioner for an easy-adhesive layer. Most preferably, the weight average molecular weight is within the range of 800-3000, and more preferably within the range of 800-1500.

The weight average molecular weight in the present invention refers to the weight average molecular weight in terms of polystyrene as measured by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent. For the situation that cannot be determined by tetrahydrofuran, use dimethylformamide. If it is still unable to be measured, use hexafluoroisopropanol. If it is still impossible to use hexafluoroisopropanol, use 2-chloronaphthalene. To measure.

The types of compounds that can be used as the surface conditioner for the hard coat layer of the present invention are not particularly limited, for example, polysiloxane-based, acrylic-based, fluorine-based, acetylene-based compounds, etc. can also be used. A commercially available product with a molecular weight of 4,000 or less.

Also, from the viewpoint of adhesion, the compound used as the surface conditioner for the hard coat layer of the present invention is preferably the same compound as the polyether-modified polysiloxane used as the surface conditioner for the easily-adhesive layer.

In the case where the composition for forming the hard coat layer is directly coated on the easy-adhesive layer, the surface regulator for the easily-adhesive layer that is originally adsorbed and aligned on the surface of the easy-adhesive layer is the surface of the hard coat layer that intends to form a new air-liquid interface Carry out adsorption and alignment, and move from the surface of the easy-adhesive layer. Instead, the surface regulator for the hard coat layer is adsorbed and aligned on the surface of the easy-adhesive layer (the interface between the easy-adhesive layer and the hard coat layer). Such a phenomenon is partially suppressed by making the weight-average molecular weight of the surface conditioner for a hard coat layer 4000 or less to make it slightly smaller, but it cannot be completely suppressed. However, if the surface conditioner for the hard coat layer and the surface conditioner for the easy-adhesive layer are the same compound, even if the movement of the surface conditioner occurs, the same compound will be aligned at the interface between the easily-adhesive layer and the hard coat layer. Excellent adhesion. In addition, "being the same compound" means compounds having the same structure and molecular weight.

[content] The content per unit thickness (solid content ratio) of the surface conditioner for the hard coat is preferably 0.3 to 3% by mass, more preferably 0.4 to 2% by mass relative to the total mass per unit thickness of the material for the hard coat . If the surface conditioner for hard coat is at least 0.3% by mass per unit thickness of the material for hard coat, the surface of the hard coat which is the gas-liquid interface can be filled with the surface conditioner for hard coat. Full, so the adhesion is excellent. Moreover, if it is 3 mass % or less, since the aggregation of a surface modifier can be suppressed, the appearance of the optical film as a whole when forming a hard-coat layer by coating is excellent.

Also, the content (solid content ratio) Mh of the polyether-modified polysiloxane which is a surface conditioner in the hard coat layer is represented by the following formula (II). Formula (II): Mh=(thickness of the hard coat layer x solid content ratio per unit thickness of the surface conditioner contained in the hard coat layer)

Mh is preferably in the range of 0.15-12. When Mh is 0.15 or more, the surface tension difference is small at the interface between the easy-adhesive layer and the coating film when the composition for forming a hard-coat layer is applied to the easily-adhesive layer, and sagging is less likely to occur. In addition, when Mh is 12 or less, the surface conditioner is less likely to aggregate. Therefore, if Mh exists in the said range, the optical film with high transparency can be obtained. Mh is more preferably in the range of 0.5-8, and is still more preferably in the range of 1-3.

In addition, by setting Mh/Mp in the range of 0.02 to 40, an optical film with high transparency can be obtained.

＜1.2.3 Other additives＞ In addition, in the composition for forming a hard coat layer, according to the purpose of increasing the hardness of the hard coat layer, suppressing shrinkage during hardening, preventing blocking, controlling the refractive index, imparting anti-glare properties, and controlling the properties of the hard coat surface, it is also possible to add Previously known microparticles, dispersants, antistatic agents, silane coupling agents, tackifiers, anti-coloring agents, colorants (pigments, dyes), defoamers, flame retardants, tackifiers, polymerization inhibitors, anti- Oxidizing agents, surface modifiers, etc. Moreover, the above-mentioned composition for forming a hard coat layer may contain a photosensitizer, and specific examples thereof include n-butylamine, triethylamine, poly-n-butylphosphine, and the like.

In addition, for the purpose of imparting light resistance, it is preferable to add an ultraviolet absorber or a pigment compound. Examples of the ultraviolet absorber include triazine-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, hydroxybenzophenone-based ultraviolet absorbers, salicylate-based A ultraviolet absorber, a cyanoacrylate type ultraviolet absorber, etc. can be used individually by 1 type or in combination of 2 or more types. Moreover, as a dye compound, a formimine type compound, an indole type compound, a cinnamic acid type compound, a pyrimidine type compound, a porphyrin type compound, a dicyano methine type compound, etc. are mentioned, for example.

In particular, it is preferable that the hard coat layer contains fine particles. The content of fine particles is preferably fine particles:active energy ray curable resin=100:100-400:100. By including fine particles in such a content, the dimensional variation of the hard coat layer can be reduced. The fine particles here are not particularly limited, but are preferably fine particles made of metal oxides (hereinafter also referred to as "metal oxide particles"). Examples of the metal oxide here include silica, alumina, zirconia, titanium oxide, antimony pentoxide, and the like. Among them, the metal oxide particles are preferably composed of silica. Silica fine particles may also be hollow particles with cavities formed inside.

The aforementioned microparticles are preferably coated with a polymer silane coupling agent. By coating the surface of the fine particles with the polymer silane coupling agent, the fine particles can be uniformly dispersed in the composition for forming a hard coat layer. The average particle size of the fine particles coated with the polymer silane coupling agent is preferably 5-500 nm, more preferably 10-200 nm. By using fine particles with such an average particle diameter, the optical characteristics of the hard coat layer can be improved.

The polymer silane coupling agent can be adjusted by reacting a polymerizable monomer with a silane coupling agent (reactive silane compound). Examples of the polymerizable monomer include monomers having ethylenically unsaturated double bonds, preferably monomers selected from (meth)acrylic acid and its derivatives. The reactive silane compound is preferably a hydrolyzable silane compound in which three alkoxy groups and one functional group are bonded to the silicon atom. As the functional group bonded to the silicon atom, a group having a group selected from (meth)acryloxy group, epoxy group (glycidyl group), carbamate group, amine group, fluorine group, and mercapto group can be mentioned. 1 or more than 2 kinds of foundations.

The polymer silane coupling agent can be prepared, for example, according to the method for preparing the reactant of a polymerizable monomer and a reactive silane compound disclosed in Japanese Patent Application Laid-Open No. 11-116240. The number average molecular weight of the polymer silane coupling agent is preferably 2,500 to 150,000 in terms of polystyrene, more preferably 2,000 to 100,000.

For the method of coating the surface of fine particles with a polymer silane coupling agent, silica fine particles are used as an example to describe. First, a dispersion liquid in which silica microparticles and a polymer silane coupling agent are dispersed in an organic solvent is produced. Alkali is added to the dispersion to generate OH groups on the surface of the silica particles, and the polymer silane coupling agent is adsorbed on the OH groups. Alternatively, the OH group is bonded to the OH group of the polymer silane coupling agent through a dehydration reaction. Finally, the silica microparticles adsorbed or bonded by the polymer silane coupling agent are separated from the dispersion and dried, thereby obtaining the silica microparticles coated with the polymer silane coupling agent.

＜1.2.4 Formation method of hard coating＞ The preparation method of the composition for forming the hard coat layer is not particularly limited as long as the solid components contained in the hard coat layer can be uniformly mixed in a solvent. It is prepared by mixing or dissolving using known devices such as mixers, bead mills, kneaders, and mixers.

The composition for forming a hard coat layer is coated on the surface of the easy-adhesive layer, and the hard coat layer is formed by curing the active energy ray-curable resin in the coating film. As a coating method of the composition for hard-coat layer formation, the conventionally well-known method can be applied without limitation in particular. For example, in the case of forming a uniform thin film layer, the gravure coating method is preferable, and in the case where it is necessary to form a thick film layer, the die coating method is preferable. After removing the solvent from the coating film as necessary, the active energy ray-curable resin is cured by irradiating active energy rays to obtain a hard coat layer.

＜1.3 Substrate film＞ The base film of the present invention is not particularly limited, and any film can be used. The thickness is not particularly limited, but it is preferably 1 to 500 μm from the viewpoint of workability such as strength and handleability, and film properties. within the range. The optical film of the present invention is included in a polarizing plate. From the viewpoint of functioning as a protective film, it is preferably formed of a thermoplastic resin material excellent in transparency, mechanical strength, thermal stability, moisture barrier property, and isotropy. A thermoplastic elastomer, a rubbery polymer, organic microparticles, inorganic microparticles, etc. may be contained as a film-forming component within the range which does not impair the effect of this embodiment. In addition, the rubber particles described in the acrylic resin described later are included in the organic fine particles.

Therefore, the resin for the base film is not particularly limited, and thermoplastic resins are preferable, for example, cellulose ester resins, polyester resins, polycarbonate resins, polyarylate resins, acrylic resins, polyphenylene resins, etc. Vinyl resin, acrylonitrile-styrene copolymer (AS resin), polyamide resin, polyimide resin, polyester resin, polyether resin, polyolefin resin, cycloolefin resin, polyvinyl chloride resin, polyethylene Alcohol resins, polyvinyl butyral resins, epoxy resins, norcamphene resins, fluororesins, etc.

The thermoplastic resin may be used alone or in combination of two or more. Furthermore, in addition to the above-mentioned thermoplastic resins, thermoplastic elastomers, rubbery polymers, organic fine particles, inorganic fine particles, etc. may be contained as film-forming components within the range that does not impair the effects of the present embodiment. In addition, the rubber particles described in the acrylic resin described later are included in the organic fine particles. In addition, other additives such as antioxidants, plasticizers, antistatic agents, release agents, tackifiers, and ultraviolet absorbers may be contained within the range that does not impair the effects of the present embodiment.

The base film can be a single layer or a laminated film of two or more layers. In the case of a laminated film having two or more layers, the thermoplastic resins used for forming each layer may be the same or different. As a method for producing the laminated film, conventionally known methods can be applied without particular limitation.

As the thermoplastic resin used for forming the base film, cycloolefin resins, cellulose ester resins, and acrylic resins are preferable from the viewpoints of transparency, mechanical strength, and the like. Among them, the most preferable thermoplastic resin is a cycloolefin resin whose polarity is low so that it is not easily affected by moisture, and whose refractive index is not easily changed by wavelength.

＜1.3.1 Resin for substrate film＞ (cycloolefin resin) As cycloolefin resin used in this invention, the (co)polymer which has the structure represented by following general formula (2) is mentioned preferably.

In the general formula (2), R ¹ to R ⁴ are each independently a hydrogen atom, a hydrocarbon group, a halogen atom, a hydroxyl group, an ester group, an alkoxy group, a cyano group, an amido group, an imide group, a silicon group, or a polar A hydrocarbon group substituted with a halogen atom, a hydroxyl group, an ester group, an alkoxy group, a cyano group, an amido group, an imide group, or a silicon group. However, two or more of R ¹ to R ⁴ may be bonded to each other to form an unsaturated bond, a monocyclic ring or a polycyclic ring, and the monocyclic or polycyclic ring may have a double bond, or may form an aromatic ring. R ¹ and R ² , or R ³ and R ⁴ can also form an alkylene group. p and m are integers of 0 or more.

In the general formula (2), R ¹ and R ³ are a hydrogen atom or a hydrocarbon group having 1-10 carbons, more preferably 1-4, particularly preferably 1 or 2 carbons. R ² and R ⁴ are a hydrogen atom or a monovalent organic group, wherein at least one of R ² and R ⁴ is a polar group other than a hydrogen atom and a hydrocarbon group. m is an integer of 0-3, p is an integer of 0-3, more preferably m+p=0-4, more preferably 0-2, particularly preferably m=1 and p=0. A specific monomer with m=1 and p=0 is preferable because the obtained cycloolefin resin has a high glass transition temperature and excellent mechanical strength.

As the polar group of the specific monomer mentioned above, carboxyl group, hydroxyl group, alkoxycarbonyl group, allyloxycarbonyl group, amine group, amido group, cyano group, etc. can be mentioned. Link base bond. In addition, a polar group such as a carbonyl group, an ether group, a silyl ether group, a thioether group, an imine group, and a divalent organic group having a polarity as a linking group and bonded thereto can also be mentioned as a polar group. Among these, a carboxyl group, a hydroxyl group, an alkoxycarbonyl group or an allyloxycarbonyl group is preferable, and an alkoxycarbonyl group or an allyloxycarbonyl group is particularly preferable.

In addition, at least one of R ² and R ⁴ is a monomer with a polar group represented by the formula -(CH ₂ ) _n COOR, because the obtained cycloolefin resin has a high glass transition temperature and low hygroscopicity, and Excellent adhesion of various materials, so it is preferred. In the above specific polar group formula, R is a hydrocarbon group having 1 to 12 carbon atoms, more preferably 1 to 4 carbon atoms, particularly preferably 1 to 2 carbon atoms, more preferably an alkyl group.

Specific examples of the copolymerizable monomer include cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, and dicyclopentadiene. The carbon number of the cycloolefin is preferably within the range of 4-20, and more preferably 5-12.

In this embodiment, cycloolefin resin may be used individually by 1 type, or may use 2 or more types together.

The preferred molecular weight of the cycloolefin resin in this embodiment is 0.2-5dL/g at the intrinsic viscosity [η]inh, more preferably 0.3-3dL/g, especially preferably 0.4-1.5dL/g. The polystyrene-equivalent number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is 8,000 to 100,000, more preferably 10,000 to 80,000, particularly preferably 12,000 to 50,000, and the weight average molecular weight (Mw) is 20,000 to 300,000. More preferably, it is in the range of 30,000 to 250,000, and particularly preferably in the range of 40,000 to 200,000.

Since the intrinsic viscosity [η] inh, the number average molecular weight and the weight average molecular weight are within the above-mentioned ranges, the heat resistance, water resistance, chemical resistance, and mechanical properties of the cycloolefin resin, as well as the ring of this embodiment Formability of olefin film becomes good.

In addition, the number average molecular weight uses the value measured by the high performance liquid chromatography under the following conditions. Solvent: dichloromethane Pipe string: Shodex K806, K805, K803G (connected to 3 Showa Denko (stock) manufacturers) Sample concentration: 0.1% by mass Detector: RI Model 504 (manufactured by GL Sciences) Pump: L6000 (manufactured by Hitachi, Ltd.) Flow: 1.0mL/min Temperature: 23°C Calibration curve: A calibration curve generated using 13 samples of standard polystyrene STK standard polystyrene (manufactured by Tosoh Co., Ltd.) Mw = 500 to 2,800,000. 13 samples are preferably used at almost equal intervals.

The glass transition temperature (Tg) of the cycloolefin resin of this embodiment is usually 110°C or higher, preferably 110 to 350°C, more preferably 120 to 250°C, particularly preferably 120 to 220°C. When the Tg is above 110°C, it is less likely to be deformed due to use under high temperature conditions or due to secondary processing such as coating and printing, so it is preferable. On the other hand, by setting Tg to be 350° C. or lower, molding processing can be avoided, and the possibility of resin deterioration due to heat during molding processing can be suppressed.

In the cycloolefin resin, specific hydrocarbon-based resins such as those described in JP-A-9-221577 and JP-A-10-287732 may be blended within the range that does not impair the effects of the present embodiment. Or known thermoplastic resins, thermoplastic elastomers, rubbery polymers, organic microparticles, inorganic microparticles, etc., may also contain specific wavelength dispersants, sugar ester compounds, antioxidants, peel accelerators, rubber particles, plasticizers , UV absorbers and other additives.

Moreover, it is preferable to use a commercial item as a base film using a cycloolefin resin. Commercially available products, for example, are sold under the trade names of Arton (Arton: registered trademark) G (G7810, etc.), Arton F, Arton R, and Arton RX by JSR Co., Ltd. It is commercially available under the trade names of Zeonor (Zeonor: registered trademark) ZF14, ZF16, ZEONEX (Zeonex: registered trademark) 250 or ZEONEX 280, and these can be used.

(cellulose ester resin) As the cellulose ester resin used in the present invention, for example, triacetyl cellulose, cellulose acetate propionate, cellulose diacetate, cellulose acetate butyrate, etc. are preferably mentioned. In addition, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polycarbonate resins, polyolefin resins such as polyethylene and polypropylene, norbornene resins, fluororesins, etc. , cycloolefin resin, etc., used in combination with cellulose ester resin.

The cellulose ester used in the base film of the present invention is preferably a carboxylate having 2 to 22 carbon atoms, and may be an ester of an aromatic carboxylic acid, preferably a lower fatty acid ester of cellulose. Here, the "lower fatty acid" in the lower fatty acid ester of cellulose means a fatty acid having 6 or less carbon atoms.

Also, the acyl group bonded to the hydroxyl group of the glucose unit constituting the cellulose ester may be a straight chain hydrocarbon group, a branched hydrocarbon group, or a cyclic hydrocarbon group, and the acyl group may be substituted with other substituents. In the case where the degree of substitution of the substituents bonded to the hydroxyl group of the cellulose ester is the same, if the carbon number of the lower fatty acid exceeds 7, the birefringence will decrease, so the acyl group bonded to the hydroxyl group of the glucose unit constituting the cellulose ester The carbon number of the group is preferably 2-6, more preferably 2-4, more preferably 2-3.

In the present invention, the cellulose ester can use an acyl group derived from a mixed acid, preferably an acyl group with 2 and 3 carbons, or an acyl group with 2 and 4 carbons. As a specific example of such a cellulose ester, cellulose acetate propionate, cellulose acetate butyrate, or cellulose acetate propionate butyrate in which a propionate group is bonded in addition to an acetyl group can be used. Or butyrate-based mixed fatty acid esters of cellulose. In addition, the butyryl group forming the butyrate may be linear or branched. The cellulose ester is preferably cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, or cellulose acetate phthalate.

The retardation value of the above-mentioned base film can be appropriately controlled by the type of acyl group contained in the cellulose ester, the degree of substitution of the acyl group to the pyranose ring of the cellulose resin skeleton, and the like.

The substituent bonded to the hydroxyl group of the glucose unit of the cellulose ester used in the base film preferably satisfies the following formulas (2) and (3).

Formula (2): 2.0≦X+Y≦3.0 Formula (3): 0≦Y≦2.0 In the above formula (2), X is the degree of substitution of acetyl group, and in formula (2) and formula (3), Y is the degree of substitution of propionyl group or butyryl group. By satisfying the above-mentioned formula 2, a base film exhibiting excellent optical properties can be produced. Among the above cellulose esters, triacetyl cellulose and cellulose acetate propionate are preferably used. Cellulose acetate propionate preferably has an acetyl substitution degree X of 1.0≦X≦2.5, and 0.1≦Y≦1.5, 2.0≦X+Y≦3.0.

The method for measuring the substitution degree of acyl group can be determined according to ASTM-D817-96. If the substitution degree of the acyl group is too low, there will be many unreacted parts with respect to the hydroxyl groups of the pyranose ring constituting the skeleton of the cellulose resin, and many of the hydroxyl groups will remain. Therefore, the retardation value of the base film is unfavorable because it changes due to humidity, and it is unfavorable because the ability to protect polarizers as a polarizing plate protective film decreases.

The number average molecular weight of the above-mentioned cellulose ester is preferably from 60,000 to 300,000, more preferably from 70,000 to 200,000. By using such a number average molecular weight cellulose ester, the mechanical strength of a base film can be improved. The number average molecular weight of this cellulose ester is the value measured by the high performance liquid chromatography under the following conditions.

Solvent: Acetone String: MPW×1 (manufactured by Tosoh Co., Ltd.) Sample concentration: 0.2 (mass/volume)% Flow rate: 1.0mL/min Sample injection volume: 300μL Standard sample: standard polystyrene Temperature: 23°C The cellulose used as a raw material of cellulose ester is not particularly limited, but examples thereof include cotton linters, wood pulp, kenaf, and the like. In addition, cellulose esters obtained from these materials may be mixed and used in arbitrary ratios.

As the acylation agent for the above-mentioned cellulose raw material, in the case of using acid anhydrides such as acetic anhydride, propionic anhydride, butyric anhydride, etc., organic acids such as acetic acid or organic solvents such as methylene chloride are contacted by protons such as sulfuric acid. media to react. In the case of using an acyl chloride (CH ₃ COCl, C ₂ H ₅ COCl, C ₃ H ₇ COCl) as an acylating agent, a basic compound such as an amine can be used as a catalyst. Acylation of cellulose raw materials can be synthesized by the method described in JP-A-10-45804.

In the above-mentioned cellulose ester, the average substitution degree of the acyl group at the 6-position of the glucose unit is preferably 0.5-0.9. The hydroxyl group at the 6-position of the glucose unit constituting the cellulose ester has a primary hydroxyl group that is more reactive than the hydroxyl groups at the 2-position and 3-position. This primary hydroxyl group preferentially forms sulfuric acid ester during the production process of cellulose ester using sulfuric acid as a catalyst. Therefore, in the esterification reaction of cellulose, by increasing the amount of sulfuric acid that is a catalyst, compared with general cellulose esters, the average substitution of the hydroxyl groups at the 2- and 3-positions of the glucose unit can be obtained. High degree of cellulose ester.

In addition, in order to increase the average substitution degree of the hydroxyl group at the 2-position and 3-position, the cellulose ester may also be tritylated as required. The hydroxyl group at the 6-position of the glucose unit constituting the cellulose ester is selectively protected by tritylation, whereby the hydroxyl groups at the 2-position and 3-position of the glucose unit can be esterified intensively. In addition, after esterifying the hydroxyl group at the 2-position and the 3-position of the glucose unit, the trityl group (protecting group) protecting the hydroxyl group at the 6-position of the glucose unit is removed, and the hydroxyl group at the 2-position and the 3-position can be detached. The average degree of substitution is higher than that of the hydroxyl group at the 6-position of the glucose unit. As such an esterification method, it is preferable to use cellulose ester produced by the method described in Unexamined-Japanese-Patent No. 2005-281645.

In the case of using acetylcellulose as the cellulose ester, in order to increase the acetylation rate of the acetylcellulose, it is necessary to prolong the time for the acetylation reaction. However, if the reaction time of the acetylation reaction is prolonged, the cellulose chain will be cut and the acetyl group will be decomposed, so it is not preferable. Therefore, in order to suppress the decomposition of acetyl cellulose while increasing the degree of acetylation of acetyl cellulose, it is preferable to set the reaction time of the acetylation reaction within a specific range. However, it is difficult to uniformly define the appropriate numerical range of the reaction time because the most suitable reaction time varies greatly due to reaction devices, reaction equipment, and other reaction conditions.

Therefore, it is preferable to use the value of weight average molecular weight (Mw)/number average molecular weight (Mn) which is an index of the reaction degree instead of the above-mentioned reaction time. Cellulose esters are similar to the decomposition of general polymers. As the decomposition progresses, the molecular weight distribution becomes wider. Therefore, the value of weight average molecular weight (Mw)/number average molecular weight (Mn) can be used to grasp the value of cellulose. Decomposition degree of ester. For example, by defining the reaction degree by weight average molecular weight (Mw)/number average molecular weight (Mn), in the process of acetylating cellulose triacetate, the reaction time of acetylation can be prevented from becoming too long And the degree of decomposition of cellulose triacetate is too high, and the reaction time of acetylation can be ensured sufficiently. The Mw/Mn ratio of the cellulose ester is preferably 1.4 to 5.0.

An example of the production method of cellulose ester is shown below. 100 parts by mass of cotton linters are pulverized as a cellulose raw material, 40 parts by mass of acetic acid are added, and the pre-treatment is activated at 36° C. for 20 minutes. After that, 8 mass parts of sulfuric acid, 260 mass parts of acetic anhydride, and 350 mass parts of acetic acid were added, and esterification was performed at 36 degreeC for 120 minutes. After neutralizing with 11 parts by mass of a 24% magnesium acetate aqueous solution, saponification aging was performed at 63° C. for 35 minutes to obtain acetyl cellulose. Use 10 times the acetic acid aqueous solution (acetic acid: water = 1: 1 (mass ratio)) to the acetyl cellulose, stir at room temperature for 160 minutes, filter and dry it to obtain a acetyl cellulose with a degree of substitution of 2.75. Refined acetylcellulose. The acetylcellulose-based Mn was 92,000, Mw was 156,000, and Mw/Mn was 1.7. Similarly, cellulose esters with different degrees of substitution and Mw/Mn ratios can be synthesized by adjusting the esterification conditions (temperature, time, stirring) and hydrolysis conditions of cellulose esters.

The cellulose ester synthesized by the above-mentioned method is preferably refined to remove low molecular weight components, preferably to remove non-acetylated or low-degree acetylated components by filtration. Moreover, when the said cellulose ester is a mixed-acid cellulose ester, it can obtain by the method described in Unexamined-Japanese-Patent No. 10-45804.

Also, the cellulose ester preferably does not contain metals such as iron (Fe), calcium (Ca), and magnesium (Mg). This is because these metal ions form insoluble nuclei by forming salts with polymer decomposition products containing organic acid groups. These trace metal components are believed to originate from the water used in the manufacturing steps contained in the cellulose ester.

Iron contained in the above-mentioned cellulose ester is preferably 1 ppm or less. Calcium contained in cellulose ester is preferably 60 ppm or less, more preferably 0 to 30 ppm. Calcium may form complexes with acidic components such as carboxylic acid or phosphonic acid, and may also form complexes with many ligands. With such zirconium systems there is occasion for the formation of scum (insoluble precipitates, turbidity) originating from insoluble calcium. Magnesium contained in cellulose ester becomes like this. Preferably it is 0-70 ppm, More preferably, it is 0-20 ppm. By setting magnesium to 70 ppm or less, generation of insoluble matter can be suppressed.

The content of the above-mentioned metals is determined by decomposing the absolutely dried cellulose ester with sulfuric acid by a Micro digest wet decomposition device, followed by pretreatment with alkali melting, and using ICP-AES ( Inductively Coupled Plasma Luminescence Spectroscopic Analysis Device) for specific analysis.

Moreover, it is preferable to use a commercial item as a base film using a cellulose ester resin. Examples of commercially available products include Konica Minolta Tuck KC8UX, KC4UX, KC8UY, KC4UY, KC6UA, KC4UA, KC2UA, KC4UE, KC4UZ, KC4CT1, and KC2CT1 (all of which are manufactured by Konica Minolta Corporation). The refractive index of the cellulose ester film is preferably 1.45-1.55. The refractive index can be measured in accordance with JIS K7142-2008.

(Acrylic) Acrylic resins are resins composed of (co)polymers obtained by (co)polymerizing monomers selected from (meth)acrylic acid and its derivatives. Units derived from monomers in (co)polymers are referred to as "structural units".

In addition, in this embodiment, "(meth)acrylic acid" means both "acrylic acid" and "methacrylic acid", and "(meth)acrylate" means "acrylate" and "methacrylic acid". Both "acryl acrylate" and "(meth)acryl" mean both "acryl" and "methacryl". For example, "urethane (meth)acrylate" means both "urethane acrylate" and "urethane methacrylate".

The acrylic resin used for the substrate film is based on the required physical properties to select the type or combination of monomers, and the composition of the monomers. In the following, while adjusting the equilibrium moisture content of the substrate film within a predetermined range, from the viewpoint of improving brittleness, etc., the acrylic resin through molecular design is used as an example to illustrate the acrylic resin. However, the acrylic resin used in the present invention is not affected. Those who are limited by this. The acrylic resin preferably comprises, for example, a structural unit (U1) derived from methyl methacrylate, a structural unit (U2) derived from phenylmaleimide, and a structural unit derived from alkyl acrylate ( U3).

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

The structural unit (U2) derived from phenylmaleimide can increase the affinity with water due to its moderate polarity. Also, since the structural unit (U2) derived from phenylmaleimide has a relatively large volume structure, it can have tiny voids in the resin matrix that allow moisture to move. Thereby, the mobility or dischargeability of the moisture of the base film can be improved.

The content of the structural unit (U2) derived from phenylmaleimide is preferably 1 to 25 mass % with respect to all structural units constituting the acrylic resin. If the content of the structural unit (U2) derived from phenylmaleimide is 1% by mass or more, since it has moderate polarity, it is not only easy to be compatible with water molecules, but also has sufficient small size to allow water molecules to move. gaps, so it is easy to increase the equilibrium moisture content. When the content of the structural unit (U2) derived from phenylmaleimide is 25% by mass or less, the brittleness of the base film is less likely to be impaired. From the viewpoint of the above, the content of the structural unit (U2) derived from phenylmaleimide is more preferably 7 to 15% by mass.

The structural unit (U3) derived from alkyl acrylate, for example, can improve the dispersion of rubber particles because the polymer constituting the shell described later has good affinity with the rubber particles containing the structural unit derived from butyl acrylate. sex.

The alkyl acrylate is an alkyl acrylate having 1-7, preferably 1-5, carbon atoms in the alkyl moiety. Examples of alkyl acrylate include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, and the like.

The content of the structural unit (U3) derived from an alkyl acrylate is preferably 1 to 25 mass % with respect to all structural units constituting the acrylic resin. If the content of the structural unit (U3) derived from the alkyl acrylate is 1% by mass or more, moderate flexibility can be imparted to the acrylic resin, so the film will not become too brittle and will not easily break. If the content of the structural unit (U3) derived from alkyl acrylate is 25% by mass or less, the Tg of the acrylic resin will not be too low, so not only the heat resistance of the base film will not be easily damaged, but also the mechanical strength will not be easily damaged. . Content of the structural unit derived from an alkyl acrylate is more preferably 5-15 mass % from the said viewpoint.

The ratio of the structural unit (U2) derived from phenylmaleimide to the total amount of the structural unit (U2) derived from phenylmaleimide and the structural unit (U3) derived from alkyl acrylate The ratio is preferably from 20 to 70% by mass. When this ratio is 20 mass % or more, it becomes easy to improve the heat resistance of a base film, and when it is 70 mass % or less, a base film becomes difficult to become too brittle.

The glass transition temperature (Tg) of the acrylic resin is preferably 110°C or higher, more preferably 120-150°C. When the Tg of the acrylic resin is within the above range, it is easy to improve the heat resistance of the base film. In order to adjust the Tg of the acrylic resin, for example, it is preferable to adjust the content of the structural unit (U2) derived from phenylmaleimide or the structural unit (U3) derived from alkyl acrylate.

The weight average molecular weight (Mw) of the acrylic resin is preferably 500,000 or more. If the weight average molecular weight of the acrylic resin is more than 500,000, the viscosity of the dope used for solution casting will not become too low, so not only the aggregation of rubber particles can be suppressed, but also the flatness of the surface of the substrate film can be suppressed lowered. Moreover, if the weight average molecular weight of an acrylic resin is 500,000 or more, sufficient mechanical strength (toughness) can be given to a base film. The weight average molecular weight of the acrylic resin is more preferably from 500,000 to 3 million, and still more preferably from 600,000 to 2 million, from the above viewpoint. The weight average molecular weight can be measured by the same method as above.

The content of the acrylic resin is preferably at least 60% by mass, more preferably at least 70% by mass, based on the base film.

When the base film is mainly composed of acrylic resin, rubber particles having a function of imparting toughness (flexibility) to the base film may be contained. The rubber particles are particles comprising a rubber-like polymer. The rubbery polymer is a soft cross-linked polymer with a glass transition temperature below 20°C. Examples of such cross-linked polymers include butadiene-based cross-linked polymers, (meth)acrylic-based cross-linked polymers, and organosiloxane-based cross-linked polymers. Among them, a (meth)acrylic cross-linked polymer is preferable, and an acrylic cross-linked polymer (acrylic acid) is more preferable from the standpoint that the difference in refractive index with the acrylic resin is small and the transparency of the substrate film is less likely to be impaired. rubbery polymer).

The rubber particles are preferably particles containing an acrylic rubber-like polymer. The acrylic rubber-like polymer is a cross-linked polymer comprising a structural unit derived from acrylate as a main component. Inclusion as a main component means that the content of the structural unit derived from acrylate is 40% by mass or more. The acrylic rubber-like polymer preferably contains a structural unit derived from an acrylate, a structural unit derived from another monomer copolymerizable therewith, and a polymer having two or more radically polymerizable groups (non-copolymerizable) in one molecule. A cross-linked polymer of structural units of multifunctional monomers (reactive double bonds of yokes).

The glass transition temperature (Tg) of the rubbery polymer is preferably not higher than 0°C, more preferably not higher than -10°C. When the glass transition temperature (Tg) of the rubbery polymer is 0° C. or lower, appropriate toughness can be imparted to the film. The glass transition temperature (Tg) of the rubbery polymer was measured by the same method as described above.

The particles containing the acrylic rubber-like polymer may also be core-shell type particles having a core part containing the acrylic rubber-like polymer and a shell part covering it. The shell part preferably comprises a methacrylic polymer mainly composed of a structural unit derived from methacrylate, which is graft-bonded to an acrylic rubber-like polymer.

The average particle size of the rubber particles can be obtained by measuring the dispersed particle size of the rubber particles in the dispersion liquid with a zeta potential particle size measurement system (ELSZ-2000ZS manufactured by Otsuka Electronics Co., Ltd.). The average particle diameter of the rubber particles is preferably in the range of 100-300 nm. The content of the rubber particles is not particularly limited, but is preferably 5 to 25% by mass, more preferably 5 to 15% by mass, based on the base film.

＜1.3.2 Manufacturing method of substrate film＞ The base film of the present invention can be produced by known molding methods such as melt casting, solution casting, and calendering. Preferably, the melt casting method and the solution casting method are used, and the solution casting method is particularly preferably used.

The base film is produced by the solution casting method, specifically, a production method including the following steps (1) to (3) can be used. In addition, this manufacturing method preferably has the step of (4). (1) The step of obtaining the glue, and the glue contains: a film-forming component including a thermoplastic resin, and the above-mentioned additives as required, and a solvent (2) After casting the obtained mortar on the support, drying and peeling off to obtain a film (3) The step of drying the obtained film while stretching it as needed (4) The step of winding the obtained base film to obtain the roll body

About the steps of (1) Dissolve or disperse the film-forming components including the thermoplastic resin and the above-mentioned additives as needed in the solvent to prepare the glue.

The solvent used in the glue contains at least an organic solvent (good solvent) that can dissolve the thermoplastic resin. Also, when using an additive, it is preferable that the solubility of the additive is also high in the organic solvent. Examples of good solvents include chlorine-based organic solvents such as dichloromethane, and non-chlorinated organic solvents such as methyl acetate, ethyl acetate, acetone, and tetrahydrofuran. Among them, dichloromethane is preferred.

The solvent used in the glue may further contain a poor solvent. Examples of poor solvents include linear or branched aliphatic alcohols having 1 to 4 carbon atoms. When the ratio of alcohol in the dope becomes higher, the film-like substance tends to gel and peel off from the metal support more easily. Examples of linear or branched aliphatic alcohols having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol . Among them, ethanol is preferable from the viewpoints of high stability of the dope, relatively low boiling point, and good drying properties.

About the steps of (2) The obtained mortar was casted on a support. The casting system of the glue can be spit out from the casting die.

Next, the solvent in the dope cast on the support is evaporated and dried. The dried glue is peeled off from the support to obtain a membrane.

The amount of residual solvent in the dope when peeled from the support (the amount of residual solvent in the film-like product when peeled off) is, for example, preferably 20% by mass or more, more preferably 20 to 30% by mass. When the amount of residual solvent at the time of peeling is 30% by mass or less, excessive stretching of the film-like object due to peeling can be more easily suppressed.

The residual solvent amount of the dope at the time of peeling is defined by the following formula (4). The following contents are also the same. Equation (4) Residual solvent content of mucilage (mass%) = (mass of mucilage before heat treatment - mass of mucilage after heat treatment) / mass of mucilage after heat treatment × 100 In addition, heat treatment when measuring the amount of residual solvent refers to heat treatment at 140°C for 30 minutes.

The amount of residual solvent during peeling can be adjusted according to the drying temperature and drying time of the glue on the support, the temperature of the support, etc.

About the steps of (3) The obtained film was dried. Drying can be carried out in a single stage or in multiple stages. In addition, drying may be performed while stretching as necessary.

For example, the drying step of the membrane may also include a step of preliminarily drying the membrane (preliminary drying step), a step of extending the membrane (extending step), and a step of drying the stretched membrane (formal drying step). drying step).

(preparatory drying step) The pre-drying temperature (drying temperature before stretching) may be higher than the stretching temperature. Specifically, when the glass transition temperature of the thermoplastic resin is Tg, it is preferably (Tg-50) to (Tg+50)°C. If the pre-drying temperature is above (Tg-50)°C, it is easy to moderately volatilize the solvent, so it is easy to improve the transportability (operability), and if it is below (Tg+50)°C, the solvent will not volatilize excessively , so the extensibility in the subsequent elongation step is less likely to be damaged. The initial drying temperature can be measured as an ambient temperature such as the temperature inside the stretching machine or the temperature of hot air in (a) when drying is performed by a non-contact heating type while being conveyed by a tenter stretching machine or rollers.

(extended steps) The extension can be carried out according to the required optical characteristics, such as the retardation value, preferably in at least one direction, or in two directions orthogonal to each other (for example, the width direction of the film (TD direction) ), and the biaxial extension of the conveying direction (MD direction) orthogonal to it).

The elongation ratio when producing the base film is preferably from 5 to 100%, more preferably from 20 to 100%. In the case of biaxial stretching, it is preferable that the stretching magnifications in each direction are each within the above-mentioned range.

The elongation ratio (%) is defined by the following formula (5). Formula (5) Stretching ratio (%) = (stretching direction of the film after stretching - stretching direction of the film before stretching) / (stretching direction of the film before stretching) × 100 In addition, when performing biaxial stretching, it is preferable to set the above-mentioned stretching magnification with respect to the TD direction and the MD direction.

Stretching temperature (drying temperature during stretching), similar to the above, when the glass transition temperature of the thermoplastic resin is Tg, is preferably Tg (°C) or higher, more preferably (Tg+10) to (Tg+ 50)°C. If the stretching temperature is above Tg (°C), preferably above (Tg+10)°C, since it is easy to moderately volatilize the solvent, it is easy to adjust the stretching tension to an appropriate range. If it is (Tg+50)°C Below, since the solvent system does not volatilize excessively, the extensibility system is less likely to be damaged. The stretching temperature during the production of the base film can be set to, for example, 115° C. or higher. As for the stretching temperature, it is preferable to measure (a) the ambient temperature such as the temperature inside the stretching machine in the same manner as above.

The amount of residual solvent in the film at the start of stretching is preferably the same as the amount of residual solvent in the film at the time of peeling, for example, preferably 20-30% by mass, more preferably 25-30% by mass .

The stretching of the TD direction (width direction) of the film can be carried out by, for example, fixing both ends of the film with clamps or pins, and expanding the distance between the clamps or pins in the direction of progress (stenter method). . The stretching of the film in the MD direction can be performed, for example, by a method (roll method) in which a peripheral speed difference is generated between a plurality of rolls and the difference in the peripheral speed of the rolls is utilized.

(official drying step) From the viewpoint of further reducing the amount of residual solvent, it is preferable to further dry the film obtained after stretching. For example, it is preferable to further dry the film obtained after stretching while conveying it with a roll or the like.

The official drying temperature (drying temperature in the case of no stretching), when the glass transition temperature of the thermoplastic resin is set as Tg, is preferably (Tg-50) ~ (Tg-30) ° C, more preferably (Tg-40 )～(Tg-30)℃. If the post-drying temperature is above (Tg-50)°C, it is easy to volatilize and remove the solvent from the stretched film, and if it is below (Tg-30)°C, the deformation of the film can be highly suppressed Wait. As for the main drying temperature, it is preferable to measure ambient temperature such as (a) hot air temperature in the same manner as above.

About the steps of (4) The obtained base film is preferably long. The long base film is wound into a roll to form a roll body.

The length of the elongated base film is not particularly limited, but may be, for example, about 100 to 10000 m. Moreover, the width of the base film is preferably at least 1 m, more preferably 1.3 to 4 m.

The thickness of the base film can be appropriately determined, but generally, it is preferably in the range of 1 to 500 μm from the viewpoint of workability such as strength and handleability, and film properties. The thickness of the base film is more preferably in the range of 5-50 μm, and more preferably in the range of 10-45 μm.

＜＜2 Manufacturing method＞＞ The manufacturing method of the optical film of the present invention is characterized in that it includes the step of forming the aforementioned easy-adhesive layer on the aforementioned base film, and the step of forming the aforementioned hard coat layer on the aforementioned easily-adhesive layer.

The formation method of each layer is not particularly limited, but coating method is preferred. For example, it can be obtained by applying a composition for forming an easily-adhesive layer on the surface of a base film, drying it, and further applying a composition for forming a hard coat layer and irradiating it with active energy rays.

By forming the easy-adhesive layer and the hard coat layer by the coating method respectively in this way, each layer can contain the said surface control agent, and can fully exhibit the function as a surface control agent. Also, by forming an easy-adhesive layer and a hard coat layer sequentially on the base film, and aligning the surface regulator for the easily-adhesive layer at the interface between the easy-adhesive layer and the hard coat layer, sufficient adhesion can be obtained. Therefore, a thin optical film having excellent interlayer adhesion can be obtained.

＜＜3 Polarizer＞＞ The polarizing plate of the present invention is characterized in that it comprises the optical film of the present invention. FIG. 2 shows an example of a preferable layer constitution of the polarizing plate of the present invention, but is not limited thereto.

Fig. 2 is a cross-sectional view showing the basic structure of the layer structure of the polarizing plate of the present invention. The polarizing plate of the present invention has the optical film of the present invention on one side of the polarizer layer 12 and the protective film 13 on the other side through the adhesive layer 11 . In addition, an adhesive layer 14 may be provided in consideration of mounting on a display device.

＜3.1 Polarizer layer＞ The polarizing plate of the present invention can be obtained by further laminating polarizer layers on the optical film of the present invention. In addition, the so-called "polarizer" refers to an element that allows only light of a polarized surface in a certain direction to pass through. Hereinafter, an example is shown with respect to a preferred configuration of the polarizer layer in the present invention, but it is not limited thereto.

The type of the polarizer layer is not particularly limited, and it may be a film type or a coating type. Also, the thickness of the polarizer layer is not particularly limited, but is preferably within a range of 0.1 to 80 μm from the viewpoint of obtaining a thin polarizing plate.

As a thin-film polarizer layer, a resin film is dyed with iodine or a dichroic dye. The resin used in the resin film can be a hydrophobic resin or a hydrophilic resin, but it is preferably a hydrophilic resin, for example, polyvinyl acetate resin, ethylene-vinyl acetate copolymer resin (EVA), etc., especially preferred For polyvinyl alcohol film.

More specifically, it can be a polyvinyl alcohol film dyed with iodine or a dichroic dye after uniaxial stretching, or a polyvinyl alcohol film dyed with iodine or a dichroic dye and then uniaxially stretched. film. In addition, it is also possible to further perform a durability treatment with a boron compound. The thickness of the usable polyvinyl alcohol film is preferably in the range of 5-50 μm, and the elongation ratio is preferably 3-7 times. Regarding the polarizer film obtained in this manner, those dyed with iodine have excellent polarizing properties, and those dyed with a dichroic dye have excellent durability.

As the coating-type polarizer layer, there are polymerizable liquid crystal compounds and polymerizable liquid crystal compositions composed of iodine or dichroic dyes as thin films. Here, the term "polymerizable liquid crystal compound" refers to a liquid crystal compound having at least one polymerizable group.

More specifically, a coating film is formed from the polymerizable liquid crystal composition, and after the solvent is removed from the coating film, the temperature is raised to a temperature at which the polymerizable liquid crystal compound phase transitions to a liquid phase or higher, and then the temperature is lowered to obtain the polymerizable liquid crystal compound. The compound phase is transferred to the smectic phase, and the polymerizable liquid crystal compound is polymerized while maintaining the smectic phase, whereby the coating type polarizer layer can be obtained. Also, from the viewpoint of increasing the liquid crystal alignment degree, it is preferable that the coating-type polarizer layer be laminated via a liquid crystal alignment layer.

The thickness of the coating-type polarizer layer can be appropriately selected according to the applicable display device, preferably in the range of 0.1-5 μm, more preferably in the range of 0.3-4 μm, and more preferably in the range of 0.5-3 μm within the range. If the thickness becomes too thinner than this range, the necessary light absorption may not be obtained, and if the thickness becomes too thicker than this range, the alignment adjustment force performed by the liquid crystal alignment layer will be reduced, and alignment defects will be caused. easy to produce. Moreover, in the case of including a liquid crystal alignment layer, the thickness of the liquid crystal alignment layer is preferably within a range of 10 to 5000 nm, more preferably within a range of 10 to 1000 nm.

＜3.2 Protective film＞ In order to impart strength to the polarizing plate, it is preferable to sandwich both sides of the polarizer layer with protective films. In the present invention, it is preferable to set one side as the optical film of the present invention. As the protective film, any film can be used, but a film suitable for use as the above-mentioned base film can also be suitably used for the protective film.

＜3.3 Bonding layer＞ The polarizer layer and the protective film, for example, are preferably bonded through an adhesive layer. The adhesive layer may be a layer obtained by drying a water-based adhesive, or may be a cured product layer of an active energy ray-curable adhesive. In addition, the metal compound filler may be contained in the adhesive layer.

The adhesive used in the adhesive layer is not particularly limited, and examples of water-based adhesives include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based adhesives, water-based adhesives, and water-based adhesives. Polyurethane-based adhesives, water-based polyester-based adhesives, etc. As a polyvinyl-alcohol-type adhesive agent, a complete saponification type polyvinyl-alcohol aqueous solution (water paste) is mentioned specifically,. Examples of the active energy ray-curable adhesive include ultraviolet-curable adhesives, electron beam-curable adhesives, and the like.

The thickness of the adhesive layer is preferably in the range of 10-75 μm, more preferably in the range of 12-50 μm.

＜3.4 Adhesive layer＞ In consideration of mounting the polarizing plate of the present invention on the viewing side of the organic EL element, the polarizing plate of the present invention preferably has an adhesive layer.

The adhesive used in the adhesive layer is not particularly limited, and examples include rubber-based adhesives, acrylic adhesives, silicone-based adhesives, urethane-based adhesives, and vinyl alkyl ether adhesives. adhesives, polyvinyl alcohol-based adhesives, polyvinylpyrrolidone-based adhesives, polyacrylamide-based adhesives, cellulose-based adhesives, etc. Among these, it is preferable to use an acrylic adhesive from the viewpoint of excellent optical transparency, weather resistance, heat resistance, and the like. In addition, in the present invention, an acrylic adhesive containing a (meth)acrylic polymer as a base polymer is preferable.

The method for forming the adhesive layer is not particularly limited, and it can be formed by a method generally used in this field. Specifically, it can be formed by coating the above-mentioned adhesive or an adhesive composition containing its raw materials and a solvent on at least one side of a substrate, and drying the coating film formed by the adhesive composition, or by irradiating ultraviolet rays, etc. The active energy lines are formed. In the case of an acrylic adhesive, the adhesive composition contains a monomer that becomes a structural unit of a polymer, a polymerization initiator, and a solvent.

The adhesive composition can be directly coated on the protective film as a base material, or after being coated on the release film, the formed adhesive layer can be transferred to the protective film and the release film can be peeled off. The thickness of the adhesive layer is preferably in the range of 10-75 μm, more preferably in the range of 12-50 μm.

＜＜4 Display Device＞＞ The display device of the present invention is characterized in that it comprises the optical film of the present invention. More specifically, the display device of the present invention can be obtained by including the polarizing plate of the present invention. The so-called display device refers to a device having a display mechanism, and includes a light-emitting element or a light-emitting device as a light-emitting source. Examples of display devices include liquid crystal display devices, organic electroluminescence (EL) display devices, inorganic electroluminescence (EL) display devices, touch panel display devices, electron emission display devices (field emission display devices (FED, etc.) , surface electron emission display device (SED)), electronic paper (display device using electronic ink or electrophoretic elements), plasma display device, projection display device (with grid light valve (GLV) display device, digital micromirror device ( DMD) display devices, etc.) and piezoelectric ceramic displays, etc.

The liquid crystal display device includes any of a transmissive liquid crystal display device, a semi-transmissive liquid crystal display device, a reflective liquid crystal display device, a direct-view liquid crystal display device, and a projection type liquid crystal display device. These display devices may be display devices representing 2-dimensional images, or may be stereoscopic display devices representing 3-dimensional images.

The display device of the present invention is preferably a touch panel display device from the viewpoint of having a hard coat layer, scratch resistance, and shock resistance. In addition, the display device of the present invention is excellent in safety and durability because it includes an optical film with improved interlayer adhesion and light resistance in addition to scratch resistance and impact resistance. [Example]

Hereinafter, although an Example is given and this invention is concretely demonstrated, this invention is not limited to these. In addition, in an Example, although the expression of "part" or "%" is used, it means "part by mass" or "% by mass" unless otherwise specified.

<Example 1> [Production of Optical Film 101] [Manufacturing of Substrate Film (COP1)] The following components were put into an airtight container, heated and stirred to dissolve completely, and filtered using Azumi Filter Paper No. 24 (manufactured by Azumi Filter Paper Co., Ltd.) to obtain dope for substrate film (COP).

Cycloolefin resin (ARTON (registered trademark) G7810: manufactured by JSR Corporation) 95 parts by mass Dichloromethane 200 parts by mass Ethanol 10 parts by mass

The obtained cement was kept at 30°C, and the solution was evenly cast on a stainless steel belt of a metal support kept at 30°C. In addition, the dope after casting was dried until the residual solvent amount became 30% by mass, and then peeled off from the stainless steel belt to obtain a film. Next, after drying the obtained film-like material at 40 degreeC until the residual solvent amount became 10 mass %, it stretched in the width direction by 1.4 times (40%) of stretching ratios. Moreover, it was made to dry further at 150 degreeC, conveying the obtained film-shaped object by several rolls, and the base material film (COP1) of length 3000m and thickness 20 micrometers was obtained.

[Manufacturing of Substrate Film (COP2)] A base film (COP2) was obtained in the same manner except that the cycloolefin resin was changed to ZEONOR (registered trademark): manufactured by Nippon Zeon Corporation in preparation of the base film (COP1).

[Manufacturing of Substrate Film (TAC)] (The preparation of mucilage) Prepare the glue with the following composition. That is, first, dichloromethane and ethanol were added to a pressurized dissolution tank. Then, the cellulose ester was put into the pressurized dissolving tank containing the solvent while stirring, and it was completely dissolved while heating and stirring.

Cellulose esters; Triacetylcellulose 100 parts by mass Polycondensation ester compound N 2 parts by mass Polycondensation ester compound M 7 parts by mass solvent; Dichloromethane 540 parts by mass Ethanol 35 parts by mass additive; Microparticles; silica dispersion diluent 3 parts by mass UV absorber 2 parts by mass Furthermore, the above-mentioned additive components were put into an airtight container, dissolved while stirring, and filtered using Azumi Filter Paper No. 244 (manufactured by Azumi Filter Paper Co., Ltd.) to prepare dope.

In addition, the triacetyl cellulose used above was (TAC: acetyl cellulose with an acetyl substitution degree of 2.8, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., Mw 200,000). In addition, the ester compound N, the ester compound M, and the silica dispersion diluent were prepared as follows. In addition, as the ultraviolet absorber, Tinuvin 928 (trade name, manufactured by BASF JAPAN Japan Co., Ltd.) was used.

(Ester Compound N) First, put 251g of 1,2-propanediol, 354g of terephthalic acid, 680g of p-toluic acid, and 0.191g of tetraisopropyl titanate as an esterification catalyst into a 2L container equipped with a thermometer, a stirrer, and a slow and rapid cooling tube. in a four-neck flask. Next, a nitrogen stream was poured into the four-necked flask, and the temperature of the solution was gradually raised while stirring the solution until the temperature of the solution reached 230° C., and a dehydration condensation reaction was performed while observing the degree of polymerization. After completion of the reaction, the unreacted 1,2-propanediol was distilled off under reduced pressure at 200° C., thereby obtaining the ester compound N. The acid value of the ester compound N was 0.30, and the number average molecular weight was 400.

(Ester compound M) First, put 251g of 1,2-propanediol, 244g of phthalic anhydride, 103g of adipic acid, 610g of benzoic acid, and 0.191g of tetraisopropyl titanate as an esterification catalyst into a thermometer, a stirrer, an emergency In a 2L four-necked flask with a cooling tube. Next, nitrogen flow was poured into the four-necked flask, and the temperature of the solution was gradually raised while stirring the solution until the temperature of the solution reached 230° C., and a dehydration condensation reaction was performed while observing the degree of polymerization. After the reaction, the unreacted 1,2-propanediol was distilled off under reduced pressure at 200° C. to obtain the polycondensed ester compound M. The acid value of the ester compound M is 0.10, and the number average molecular weight is 450.

(Silicon dioxide dispersion) First, 10 parts by mass of AEROSIL R812 (trade name, manufactured by Japan Aerosil Co., Ltd.) and 90 parts by mass of ethanol were stirred and mixed in a dissolver for 30 minutes, and then silicon dioxide was dispersed in ethanol with a homogenizer. 88 parts by mass of dichloromethane was poured into this dispersion liquid while stirring, and the dispersion liquid was diluted by stirring and mixing with a dissolver for 30 minutes. The diluted dispersion was filtered through a microparticle dispersion diluent filter (Advantec Toyo Co., Ltd.: polypropylene wound filter TCW-PPS-1N) to obtain a silica dispersion.

(film making) The mortar prepared above was uniformly cast on a stainless steel belt support at a temperature of 22°C and a width of 1.8m using a belt casting device. On the stainless steel belt support, the solvent was evaporated until the amount of residual solvent became 20%, and the dope film (net) was peeled off from the stainless steel belt support.

Next, the stripped web was evaporated at 35°C to evaporate the solvent, and slit to a width of 1.6m. After that, it was stretched at a temperature of 160°C in the width direction (TD direction) using a tenter stretcher. 1.1 times the extension. At this time, the residual solvent amount at the time of starting the stretching by the tenter was 4% by mass.

Afterwards, the drying area at 120°C and 140°C is conveyed by many rollers, and the drying is completed, and the film is slit into a width of 1.3m, and both ends of the film are knurled with a width of 10mm and a height of 2.5μm, and then wound on the core On top, the substrate film (TAC) was fabricated. The film thickness of the substrate film (TAC) was 25 μm, and the length of the roll was 6000 m.

[Manufacturing of Base Film (Acrylic)] (The preparation of mucilage) Prepare the glue with the following composition. First, methylene chloride and ethanol were added to a pressurized dissolution tank. Next, the resin was poured into the pressurized dissolution tank while stirring. Next, the rubber particle dispersion liquid prepared above was poured in, and it was made to dissolve completely, stirring it. This was filtered using SHP150 (manufactured by ROKI TECHNO) to obtain dope.

Resin ((meth)acrylic resin) 100 parts by mass Dichloromethane 200 parts by mass Ethanol 40 parts by mass Rubber particle dispersion 200 parts by mass Tinuvin928 (trade name, manufactured by BASF JAPAN Co., Ltd.) 5 parts by mass

The (meth)acrylic resin used above is MMA/PMI/BA copolymer ((80/10/10 mass ratio), Tg: 120° C., Mw: 2 million).

In addition, the glass transition temperature (Tg) of an acrylic resin was measured based on JISK7121-2012 using DSC (Differential Scanning Colorimetry: differential scanning calorimetry).

Also, the weight average molecular weight (Mw) of the acrylic resin was measured using gel permeation chromatography (HLC8220GPC manufactured by Tosoh Corporation) and a column (TSK-GELG6000HXL-G5000HXL-G5000HXL-G4000HXL-G3000HXL series manufactured by Tosoh Corporation). Dissolve 20 mg±0.5 mg of the sample in 10 mL of tetrahydrofuran, and filter with a 0.45 mm filter. 100 mL of this solution was injected into a column (at a temperature of 40° C.), measured with a detector RI at a temperature of 40° C., and a value converted to styrene was used.

The rubber particle dispersion used above is made of acrylic rubber particles M-210 (core part: acrylic rubber-like polymer with multi-layer structure, shell part: methacrylate polymer with methyl methacrylate as the main component) 10 parts by mass of core-shell rubber particles, acrylic rubber-like polymer (Tg: about -10°C, average particle diameter: 220nm) and 190 parts by mass of dichloromethane were stirred and mixed in a dissolver for 50 minutes, It was obtained by dispersing at 1500 rpm using a Milder disperser (manufactured by Pacific Machinery Co., Ltd.).

In addition, the average particle size of the rubber particles was obtained by measuring the dispersed particle size of the rubber particles in the dispersion liquid with a zeta potential-particle size measuring system (ELSZ-2000ZS manufactured by Otsuka Electronics Co., Ltd.).

(film making) Use the glue mentioned above to make a film. Specifically, the dope was uniformly cast on a stainless steel belt support body with a width of 1800 mm at a temperature of 30° C. using an endless belt casting device. The temperature of the stainless steel strip is controlled at 28°C.

On the stainless steel belt support, the solvent was evaporated until the amount of the residual solvent in the dope after casting became 30% by mass. Next, the film was peeled from the stainless steel belt support at a peeling tension of 128 N/m to obtain a film. The amount of residual solvent in the film-like material at the time of peeling was 30% by mass.

Next, while conveying the peeled film with many rollers, the obtained film was stretched 20% in the width direction (TD direction) by a tenter at 140°C (Tg+20°C) . After that, it was further dried at 100°C (Tg-20°C) while being conveyed by a roll, and the end portion clamped by a tenter clip was slit and wound into a roll shape to obtain a length of 3000m and a width of 1.5m. , Base film (acrylic) (roll body) with a film thickness of 40 μm.

[Formation of easy-adhesive layer] The following components were diluted with a diluent (water/methanol=50/50 (mass %)) so that the solid content concentration became 5 mass%, and then stirred at room temperature to obtain an easily adhesive layer-forming composition.

Maleic acid-modified olefin (Arrow base (registered trademark) SB-1200: solid content concentration 25% by mass: manufactured by Unitika Corporation) 100 parts by mass Oxazoline group-containing polymer (epocros (registered trademark) WS-700: manufactured by Nippon Shokubai Co., Ltd.) 5 parts by mass Polyether modified polysiloxane (KF-351A: manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by mass

On the substrate film prepared above, the obtained composition was coated with a bar coater, and dried in a drying oven at 80°C for 40 seconds so that the dry film thickness became 0.4 μm Forms an easy-adhesive layer.

[Formation of hard coat layer] The following components were diluted with a diluent (propylene glycol monomethyl ether/methyl acetate=50/50 (mass %)) to obtain a composition for forming a hard coat layer.

Urethane acrylate (UA-1100H: manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) 100 parts by mass Photopolymerization initiator (Irgacure (registered trademark) 184: manufactured by BASF JAPAN Corporation) 5 parts by mass Polyether-modified polysiloxane (BYK (registered trademark) 3450: manufactured by BYK-Chemie Japan Co., Ltd.) 1 part by mass

On the easy-adhesive layer of the base film with an easy-adhesive layer prepared above, the obtained composition was coated with a bar coater, and dried in a drying oven at 50°C for 40 seconds. Let the solvent evaporate. In addition, while nitrogen blowing is performed so that the oxygen concentration becomes an environment of 1.0 volume % or less, ultraviolet rays are irradiated with an ultraviolet lamp (illuminance of the irradiated part: 100 mW/cm ² ) so that the irradiation dose becomes 0.2 J/cm ² , it was hardened to form a hard coat layer with a thickness of 3 μm, and the optical film 101 was produced.

[Production of optical films 102-122] Except that in the production of the optical film 101, the base film, the resin for the easy-adhesive layer, the surface conditioner for the easy-adhesion layer, the resin for the hard coat layer, and the surface conditioner for the hard coat layer were changed to those described in Table 1 below. , are performed in the same manner to fabricate the optical films 102-122.

In addition, the products (trade names) used are as follows. (substrate film) COP1: ARTON (registered trademark) G7810: Made by JSR Corporation COP2: ZEONOR (registered trademark) ZF14: Japan Zeonor Co., Ltd.

(resin for easy adhesive layer) Water-based polyolefin resin A: Arrow base (registered trademark) SB-1200: Solid content concentration: 25% by mass: made by Unitika Water-based polyolefin resin B: Arrow base (registered trademark) SE-1030N: Solid content concentration 22% by mass: made by Unitika Water-based polyolefin resin C: Arrow base (registered trademark) SE-1010: Solid content concentration: 20% by mass: made by Unitika Water-based polyolefin resin Cellulose-based resin: Arrow base (registered trademark) SA-1200: made by Unitika Solvent-based polyolefin resin: SURFLEN (registered trademark) P-1000: manufactured by Mitsubishi Chemical Corporation Acrylic resin: Nukote K-2: manufactured by Shin-Nakamura Chemical Industry Co., Ltd.

(Surface Conditioning Agent for Easy Adhesive Coating and Hard Coating) Polyether-modified silicone A: KF-351A: Shin-Etsu Chemical Co., Ltd. Polyether-modified silicone B: KF-6015: Shin-Etsu Chemical Co., Ltd. Polyether-modified silicone C: XIAMETER (registered trademark) OFX-0193 Fluid: Dow Toray Co., Ltd. Polyether-modified silicone D: KF-6020: Shin-Etsu Chemical Co., Ltd. Polyether-modified silicone E: KF-354L: Shin-Etsu Chemical Co., Ltd. Polyether-modified silicone F: BYK (registered trademark) 3450: BYK-Chemie JAPAN Co., Ltd. Polyether-modified silicone G: KF-352A: Shin-Etsu Chemical Co., Ltd. Fluorine compound: RS-75: manufactured by DIC Corporation

(resin for hard coat) Urethane acrylate A: UA-1100H: Shin-Nakamura Chemical Co., Ltd. Tripentaerythritol acrylate: Viscoant #300: manufactured by Osaka Organic Chemical Industry Co., Ltd. Cycloolefin skeleton-containing acrylate: A-DCP: manufactured by Shin-Nakamura Chemical Industry Co., Ltd. Polymer A: SMP-250AP: Kyoeisha Chemical Co., Ltd. Urethane acrylate B: Violet (registered trademark) UV-7630B: Mitsubishi Chemical Corporation make

The HLB value is calculated by the aforementioned formula (1).

The weight average molecular weight is measured by gel permeation chromatography (GPC) using the aforementioned tetrahydrofuran, and is a weight average molecular weight in terms of polystyrene.

＜＜Evaluation＞＞ For the produced optical films 101-122, the following evaluations were performed. The results are shown in Table II. In addition, in each item, 3 or more are regarded as passing.

(1) Adhesion In the environment of 23℃・55%RH, on the hard coat layer of the prepared optical film, follow the method of JIS-K5600-5-6, use the checkerboard peeling test fixture, and make 1mm ^2. 100 checkerboard grids. Adhesive tape No. 252 manufactured by Sekisui Chemical Industry Co., Ltd. was attached thereto, and after being evenly pressed with a spatula, peeled off in a 90-degree direction. While exchanging the adhesive tape every time it was peeled off, the peeling operation of the tape was performed 10 times, and the number of peeled checkerboards was evaluated by the following criteria. 5: No stripping 4: 1 to 2 checkerboard grids to be stripped 3: 3 to 5 checkerboard grids to be stripped 2: 6 to 15 checkerboard grids to be stripped 1: 16 checkerboard grids to be stripped above

(2) Lightfastness The prepared optical film was exposed for 300 hours at a wavelength of 300 to 400 nm and an irradiation intensity of 60 W using a xenon weather resistance tester (Suga Tester Co., Ltd., xenon weatherer NX25), and then subjected to (1) Documented adhesion test to evaluate.

(3) Cracks Put water, and organic solvent (used in SURFLEN (registered trademark) P-1000 for dispersing olefin resin) on the surface of the substrate film respectively with a dropper, and after 10 seconds gently gently Wipe to remove liquid. Calculate the area ratio of the whitened part relative to the area of the circle, and evaluate it based on the following criteria. 5: Less than 1% 4: 1~20% 3: 21-40% 2: 41~60% 1: More than 60% As a result, water was 5 and organic solvent was 1.

(4) Appearance Visually observe the surface of the prepared optical film, and calculate the number of point faults (sags) per unit area (m ² ), and calculate the average value of 10 optical film samples, by the following benchmarks for evaluation. 5: 0 4: 1-10 3: 11-20 2: 21-30 1: 31 or more

The following evaluations were performed on the produced optical films 101 and 111 to 113 . The results are shown in Table II. In addition, 3 or more are regarded as passing.

(5) Humidity and heat resistance The produced optical film was cut into a size of 10cm in length and 10cm in width, and placed under the conditions of 80°C and 90%RH for 100 hours. After that, the floating of the edges of each cut out sample was measured and evaluated on the basis of the following criteria. 5: The floating of the edge of the test piece is less than 1cm 4: The floating of the edge of the test piece is more than 1cm and less than 3cm 3: The floating of the edge of the test piece is more than 3cm and less than 4cm 2: The floating of the edge of the test piece is more than 4cm and less than 5cm 1: The test piece is cylindrical (large curl and defective)

It can be seen from Table I and Table II that the adhesion and light resistance between the layers of the optical film of the present invention are improved.

<Example 2> [Production of Optical Film 201-212] In addition to changing the thicknesses of the easy-adhesive layer and the hard coat layer of the optical film 101 produced above, the types of each surface modifier, and the solid content ratio per unit thickness as described in the following Table III, All were performed in the same manner to obtain optical films 201 to 206 . Also, the optical films 207 to 212 were produced in the same manner except that the surface modifier for the hard coat layer was changed to polyether-modified polysiloxane A. The above-mentioned appearance evaluation was performed on the produced optical films 201-212. The results are shown in Table III.

It can be seen from Table III that the optical film of the present invention is aimed at the surface regulator contained in the easy-adhesive layer and the hard coat layer. By making the value of Mh/Mp within the range of 0.02-40, the appearance of the optical film can be improved. be improved.

<Example 3> [Manufacture of Polarizing Plates 301-306] (Fabrication of thin-film polarizer layer) A polyvinyl alcohol film with a thickness of 25 μm was swelled with water at 35° C. The obtained film was immersed in an aqueous solution consisting of 0.075 g of iodine, 5 g of potassium iodide, and 100 g of water for 60 seconds, and further immersed in a 45° C. aqueous solution of 3 g of potassium iodide, 7.5 g of boric acid, and 100 g of water. The obtained film was uniaxially stretched at a stretching temperature of 55° C. and a stretching ratio of 5 times. This uniaxially stretched film was washed with water and then dried to obtain a film-type polarizer layer with a thickness of 12 μm.

(Production of Polarizing Plate) The thin-film polarizer layer and protective film (optical film or substrate film obtained above) obtained in the above manner were laminated in the combinations shown in Table IV to manufacture polarizers 301-306. In addition, the optical film and the polarizer layer are bonded using a fully saponified polyvinyl alcohol aqueous solution (water paste).

In addition, the terms described in Table IV are as follows. T1: Protective film on the viewing side (the above-mentioned optical film) T2: Protective film on the side of the liquid crystal cell (the above-mentioned substrate film) PVA: The thin-film polarizer layer obtained above

[Manufacture of liquid crystal display devices] A liquid crystal display device including the above-produced polarizing plate was fabricated. Specifically, using the Apple iPad (registered trademark) 2 (IPS mode liquid crystal display device), the pre-laminated polarizers on both sides were peeled off, and the produced polarizers were respectively bonded to the liquid crystal cells. glass surface. A liquid crystal display device was produced by laminating so that the absorption axis of the prepared polarizing plate was in the same direction as the absorption axis of the preliminarily bonded polarizing plate.

＜＜Evaluation＞＞ The following evaluations were performed on liquid crystal display devices each including the produced polarizing plates 301 to 306 . The results are shown in Table IV. In addition, in each item, 3 or more are regarded as passing.

(6) Lightfastness The manufactured liquid crystal display device was subjected to exposure irradiation for 300 hours at a wavelength of 300 to 400 nm and an irradiation intensity of 60 W using a xenon weather resistance tester (Suga Tester Co., Ltd., xenon weather tester NX25). Lights up continuously when displayed in black. At this time, the brightness unevenness at the time of black display in the case of viewing from the front direction of the liquid crystal display device was observed, and the occurrence degree of brightness unevenness was evaluated by the following criteria. 5: Unevenness is not felt 4: The intensity of the transmitted light is not felt 3: Slightly feel the intensity of the transmitted light 2: Clear shading is felt at the edge of the screen 1: With the above-mentioned shades, a clear shade can be felt in the center of the screen

(7) Humidity and heat resistance The obtained liquid crystal display device was left for 500 hours under the conditions of 80° C. and 90% RH. After that, the liquid crystal display device was made to display black at room temperature, and the presence or absence of defects (white dots) in the black display of the display screen was visually confirmed, and the following criteria were used for evaluation. 5: Defects are 0 4: 1 to 2 defects 3: There are 3 to 4 defects 2: 5 to 6 defects 1: There are 6 or more defects

As can be seen from Table IV, the display device of the present invention uses the optical film of the present invention as a protective film on the viewing side, so that the light resistance and moisture resistance of the display device are improved.

From the above results, it can be seen that the subject of the present invention can be solved by selecting the resin used for the easy-adhesive layer, and the surface conditioner used for the easily-adhesive layer and the hard coat layer. That is, it is possible to provide an optical film having improved interlayer adhesion and light resistance, a method for producing the same, and a polarizing plate and a display device having the same. [Industrial availability]

The optical film of the present invention is an optical film with improved interlayer adhesion and light resistance, so that the optical film is provided in a polarizing plate, and further used in a display device, etc., to improve the light resistance and moisture and heat resistance of the display device. sex. That is, by using the optical film of the present invention, a safe and durable display device can be provided.

1: hard coating 2: Easy bonding layer 3: Substrate film 10:Optical film 11: Then layer 12: Polarizer layer 13: Protective film 14: Adhesive layer 20: polarizer

[Fig. 1] Basic layer structure of the optical film of the present invention [Fig. 2] Basic layer structure of the polarizing plate of the present invention

1: hard coating

2: Easy bonding layer

3: Substrate film

10:Optical film

Claims (7)

An optical film, characterized in that it is an optical film with a substrate film, an easy-to-adhesive layer and a hard coat layer in sequence, wherein, The aforementioned easy-adhesive layer system contains water-based polyolefin resin, and Each of the above-mentioned easily bonding layer and the above-mentioned hard coat layer contains a surface conditioner, and The aforementioned surface regulator contained in the aforementioned easy-adhesive layer is polyether-modified polysiloxane, The HLB value of the aforementioned polyether-modified polysiloxane is in the range of 5-15, The weight average molecular weight of the said surface modifier contained in the said hard-coat layer is 4000 or less. The optical film according to claim 1, wherein the base film contains a cycloolefin resin. The optical film according to claim 1 or claim 2, wherein the surface modifier contained in the easy-adhesive layer and the hard coat layer are the same compound. The optical film according to any one of claim 1 to claim 3, wherein when the mass of the surface regulator contained in the easy-adhesive layer and the hard coat layer is respectively Mp and Mh, the optical film is characterized in that , the value of the mass ratio (Mh/Mp) is in the range of 0.02-40. A method of manufacturing an optical film, characterized in that it is a method of manufacturing an optical film as described in any one of claim 1 to claim 4, including The step of forming the aforementioned easy-adhesive layer on the aforementioned base film, and A step of forming the aforementioned hard coat layer on the aforementioned easy-adhesive layer. A polarizing plate, characterized in that it comprises the optical film described in any one of claim 1 to claim 4. A display device, characterized in that it includes the polarizing plate as described in Claim 6.

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