JP6931518B2 - Single-sided protective polarizing film, polarizing film with adhesive layer, image display device and its continuous manufacturing method - Google Patents

Description

The present invention relates to a single protective polarizing film in which a protective film is provided on only one side of a polarizing element, and a polarizing film with an adhesive layer having the single protective polarizing film and an adhesive layer. The one-sided protective polarizing film and the polarizing film with an adhesive layer can form an image display device such as a liquid crystal display device (LCD) or an organic EL display device alone or as an optical film obtained by laminating them.

In a liquid crystal display device, it is indispensable to arrange polarizing films on both sides of a glass substrate forming a liquid crystal panel surface according to the image forming method. The polarizing film is generally a film in which a protective film is attached to one side or both sides of a polyvinyl alcohol-based film and a polarizing element made of a dichroic material such as iodine with a polyvinyl alcohol-based adhesive or the like. ..

When the polarizing film is attached to a liquid crystal cell or the like, an adhesive is usually used. Further, since the polarizing film can be fixed instantly and there is no need for a drying step to fix the polarizing film, the pressure-sensitive adhesive is provided in advance as a pressure-sensitive adhesive layer on one side of the polarizing film. .. That is, a polarizing film with an adhesive layer is generally used for attaching the polarizing film.

Further, the polarizing film and the polarizing film with an adhesive layer shrink the polarizer under a harsh environment of thermal shock (for example, a heat shock test in which temperature conditions of -30 ° C and 80 ° C are repeated and a high temperature test of 100 ° C). There is a problem that cracks (through cracks) are likely to occur in the entire direction of the absorber in the absorption axis due to changes in stress. That is, the polarizing film with an adhesive layer did not have sufficient durability due to thermal shock in the harsh environment. In particular, from the viewpoint of thinning, a polarizing film with an adhesive layer using a single protective polarizing film provided with a protective film on only one side of the polarizer has insufficient durability due to the thermal shock. Further, the through cracks generated by the thermal shock are likely to occur when the size of the polarizing film is increased.

In order to suppress the occurrence of through cracks, for example, a polarizing film with an adhesive layer is proposed in which a protective layer having a tensile elastic modulus of 100 MPa or more is provided on a single protective polarizing film, and an adhesive layer is further provided on the protective layer. (Patent Document 1). Further, one side of a polarizer having a thickness of 25 μm or less has a protective layer made of a cured product of a curable resin composition, the other side of the polarizer has a protective film, and an adhesive is provided on the outside of the protective layer. A polarizing film with an adhesive layer having a layer has been proposed (Patent Document 2). The polarizing film with an adhesive layer described in Patent Documents 1 and 2 is effective from the viewpoint of suppressing the occurrence of through cracks. Further, the thinning is also performed on the polarizer, and for example, a thin polarizer showing high orientation in which the optical characteristics of the simple substance transmittance and the degree of polarization are controlled has been proposed (Patent Document 3).

JP-A-2010-09027 Japanese Unexamined Patent Publication No. 2013-160775 Japanese Patent No. 4751481

In Patent Documents 1 and 2, a single protective polarizing film having a protective film on only one side of the polarizer is used to reduce the thickness, and on the other hand, a protective layer is provided to obtain a single protective polarizing film. The occurrence of through cracks in the absorption axis direction of the polarizer is suppressed.

On the other hand, the thinning is also performed for the polarizer. When the polarizing element used for the polarizing film or the polarizing film with an adhesive layer is thinned, the change in shrinkage stress of the polarizing element becomes small. Therefore, it was found that the thinned polarizer can suppress the occurrence of the through crack.

However, in a single-protective polarizing film in which the occurrence of through cracks is suppressed or a polarizing film with an adhesive layer using the same, when the optical characteristics are controlled and the polarizer is thinned (for example, as in Patent Document 3). When the thickness is 10 μm or less), when a mechanical impact is applied to the one-sided protective polarizing film or the polarizing film with an adhesive layer using it (including the case where a load due to convex fold is applied to the polarizer side). It was found that extra-fine slits (hereinafter, also referred to as nanoslits) were partially generated in the direction of the absorber's absorption axis. It was also found that the nanoslits occur regardless of the size of the polarizing film. Furthermore, it was also found that the nanoslit does not occur when both protective polarizing films having protective films on both sides of the polarizer are used. Further, when a through crack occurs in the polarizer, the stress around the through crack is released, so that the through crack does not occur adjacently, but the nanoslits occur independently or adjacently. It turned out to occur. It was also found that the penetrating crack has a progressive property of extending in the absorption axis direction of the polarizing element in which the crack is generated, but the nanoslit does not have the progressive property. As described above, the nanoslit is a new problem that occurs when the polarizer is thin and the optical characteristics are controlled within a predetermined range in the single-protection polarizing film in which the occurrence of through cracks is suppressed. It was found that this is a problem caused by a phenomenon different from that of the through crack.

Moreover, since the nanoslit is extremely fine, it cannot be detected under a normal environment. Therefore, even if nanoslits are generated in the polarizing element, it is difficult at first glance to confirm defects due to light leakage of the single-protective polarizing film and the polarizing film with an adhesive layer using the same. That is, usually, the one-sided protective polarizing film is produced in the form of a long film and is inspected for defects by automatic optical inspection, but it is difficult to detect nanoslits as defects by this defect inspection. The defect caused by the nanoslit is that the nanoslit expands in the width direction when a single protective polarizing film or a polarizing film with an adhesive layer is attached to a glass substrate or the like of an image display panel and then placed in a heating environment. It was also found that it becomes detectable (for example, the presence or absence of the light leakage).

Therefore, in a single-protective polarizing film using a thin polarizing element or a polarizing film with an adhesive layer using the same, it is desired to suppress not only through cracks but also defects due to nanoslits. Furthermore, the one-sided protective polarizing film or the polarizing film with an adhesive layer using the same is thinner than the polarizing film having both protective configurations having protective films on both sides, so that the polarizing film is liable to break or break during handling. .. Therefore, it is desirable that the polarizing film or the polarizing film with an adhesive layer using the polarizing film is not curled at the time of handling. Further, in a single protective polarizing film with a protective layer in which a protective layer is provided by solidification or curing of the single protective polarizing film, shrinkage of the material forming the protective layer occurs at the time of forming the protective layer, and between the polarizer and the protective layer. Stress tends to accumulate in the film, and curl tends to occur. Therefore, it is desired that curl does not occur in the one-sided protective polarizing film or the polarizing film with an adhesive layer using the same protective polarizing film from the viewpoint of handleability.

The present invention is a single-sided protective polarizing film having a protective film on only one side of a thin polarizing element, wherein the polarizer has predetermined optical characteristics and suppresses the occurrence of defects and curls due to through cracks and nanoslits. It is an object of the present invention to provide a single protective polarizing film capable of providing a single protective polarizing film. Another object of the present invention is to provide a polarizing film with an adhesive layer having the single protective polarizing film and an adhesive layer.

Another object of the present invention is to provide an image display device having the one-sided protective polarizing film or the polarizing film with an adhesive layer, and a method for continuously producing the same.

As a result of diligent studies, the inventors of the present application have found that the above problems can be solved by the following single-protective polarizing film, polarizing film with an adhesive layer, and the like, and have reached the present invention.

That is, the present invention is a single protective polarizing film having a protective film on only one side of the polarizer.
The polarizer contains a polyvinyl alcohol-based resin, and the optical characteristics represented by the simple substance transmittance T and the degree of polarization P are expressed by the following formula P>-(10 ^{0.929T-42.4-1} ) × 100. (However, T <42.3) or
It is configured to satisfy the condition of P ≧ 99.9 (however, T ≧ 42.3).
And when the thickness of the polarizer is X (μm) and the thickness of the transparent resin layer is Y (μm),
X ≦ 12,
Y ≦ 15,
The present invention relates to a single protective polarizing film, which satisfies 0.15 ≦ (Y / X) ≦ 3.

In the one-sided protective polarizing film, the transparent resin layer preferably has a compressive elastic modulus of 0.1 GPa or more at 80 ° C.

In the one-sided protective polarizing film, the transparent resin layer is preferably formed of an ultraviolet curable acrylic resin, an ultraviolet curable epoxy resin, a urethane resin, or a polyvinyl alcohol resin.

In the single protective polarizing film, it is preferable to have an adhesive layer between the polarizer and the protective film. The thickness of the adhesive layer is preferably 0.1 μm or more and 5 μm or less. Further, the adhesive layer preferably has a compressive elastic modulus at 80 ° C. of 0.1 GPa or more and 10 GPa or less. Further, the adhesive layer is preferably formed of an ultraviolet curable acrylic resin, an ultraviolet curable epoxy resin, a urethane resin or a polyvinyl alcohol resin.

In the single protective polarizing film, when there is only one protective film, the thickness of the protective film is preferably 10 μm or more and 100 μm or less.

In the single protective polarizing film, when the number of protective films is two, the thickness of each protective film is 10 μm or more, and the total thickness of the protective films is 100 μm or less, and the protective films are adhered to each other. It preferably has an agent layer or an adhesive layer.

In the single-protective polarizing film, the polarizer preferably contains boric acid in an amount of 25% by weight or less based on the total amount of the polarizer.

The present invention also relates to the one-sided protective polarizing film and a polarizing film with an adhesive layer, which comprises an adhesive layer.

In the polarizing film with an adhesive layer, the thickness of the adhesive layer is preferably 1 μm or more and 40 μm or less. The pressure-sensitive adhesive layer is preferably a storage modulus at 23 ° C. is 1.0 × 10 4 ^Pa or more.

The polarizing film with an adhesive layer can be used in an embodiment in which the pressure-sensitive adhesive layer is provided on the transparent resin layer of the one-sided protective polarizing film. Further, the polarizing film with an adhesive layer can be used in a manner in which the pressure-sensitive adhesive layer is provided on the protective film of the one-sided protective polarizing film. Further, a separator may be provided on the pressure-sensitive adhesive layer of the polarizing film with the pressure-sensitive adhesive layer. A polarizing film with an adhesive layer provided with a separator can be used as a wound body.

The present invention also relates to the one-sided protective polarizing film or an image display device having the pressure-sensitive adhesive layered polarizing film.

Further, in the present invention, the polarizing film with the pressure-sensitive adhesive layer, which is unwound from the wound body of the polarizing film with the pressure-sensitive adhesive layer and conveyed by the separator, is continuously applied to the surface of the image display panel via the pressure-sensitive adhesive layer. The present invention relates to a method for continuously manufacturing an image display device, which includes a step of bonding to.

The single-protective polarizing film and the polarizing film with an adhesive layer of the present invention use a polarizer having a thickness of 12 μm or less, and are thinned. Further, in the thin polarizing element having a thickness of 12 μm or less, the change in contraction stress applied to the polarizer due to thermal shock is smaller than in the case where the thickness of the polarizer is large, so that the occurrence of through cracks can be suppressed.

On the other hand, in a thin polarizer having predetermined optical characteristics, nanoslits are likely to occur in the polarizer. The nanoslit is used in the manufacturing process of a single protective polarizing film, the manufacturing process of a polarizing film with an adhesive layer for providing an adhesive layer on the single protective polarizing film, and various processes after manufacturing the polarizing film with an adhesive layer. It is considered that it occurs when a mechanical impact is applied to the polarizing film or the polarizing film with an adhesive layer using the polarizing film, and it is assumed that it is generated by a mechanism different from the through crack caused by the thermal impact. Further, the defect due to the nanoslit is caused by the nanoslit in the width direction when a single protective polarizing film or a polarizing film with an adhesive layer is attached to a glass substrate or the like of an image display panel and then placed in a heating environment. By spreading, it becomes detectable (for example, the presence or absence of the light leakage).

In the one-sided protective polarizing film and the polarizing film with an adhesive layer of the present invention, by providing a transparent resin layer on the other side of the polarizer (the side having no protective film), a piece before the transparent resin layer is provided. Even when the nanoslit is generated in the polarizer in the state of the protective polarizing film, it is possible to suppress the occurrence of defects due to the spread of the nanoslit in the width direction. In particular, a transparent resin layer having a compressive elastic modulus at 80 ° C. of 0.1 GPa or more is effective.

As described above, the single-protective polarizing film of the present invention and the polarizing film with an adhesive layer using the same have a transparent resin layer, so that the thinning can be satisfied, and through cracks and nanon appear in the polarizer. Defects due to slits can be suppressed.

Further, in the single-protective polarizing film and the polarizing film with an adhesive layer of the present invention, the thickness X (μm) of the thin polarizing element and the thickness Y (μm) of the transparent resin layer are X ≦ 12 and Y ≦ 15. , 0.15 ≦ (Y / X) ≦ 3, and despite the provision of a transparent resin layer that can suppress through-cracks and defects due to nanoslits that occur in the polarizer. However, the occurrence of curl can be suppressed.

This is an example of a schematic cross-sectional view of the one-sided protective polarizing film of the present invention. This is an example of a schematic cross-sectional view of the polarizing film with an adhesive layer of the present invention. This is an example of a conceptual diagram comparing nanoslits and through cracks generated in a polarizer. This is an example of a photograph of a cross-sectional view of a single-protective polarizing film showing that the expansion of nanoslits by heating differs depending on the presence or absence of nanoslits and the presence or absence of a transparent resin layer when nanoslits are generated. It is the schematic explaining the evaluation item about nanoslit of an Example and a comparative example. It is an example of a photograph showing a crack generated by a nanoslit related to the evaluation of Examples and Comparative Examples. It is an example of a photograph showing the progress of through cracks related to the evaluation of Examples and Comparative Examples. This is an example of a schematic cross-sectional view of a continuous manufacturing system for an image display device.

The single protective polarizing film 11 and the polarizing film 12 with an adhesive layer of the present invention will be described below with reference to FIGS. 1 and 2. The single protective polarizing film 10 (without the transparent resin layer 3) has the protective film 2 only on one side of the polarizing element 1, for example, as shown in FIG. 1 (A). The polarizer 1 and the protective film 2 are laminated via an adhesive layer 2a (in addition, an intervening layer such as an adhesive layer and an undercoat layer (primer layer)). Further, although not shown, in the one-sided protective polarizing film 10, the easy-adhesive layer and the adhesive layer can be laminated by providing the protective film 2 with an easy-adhesive layer or applying an activation treatment. As shown in FIG. 1, the single-sided protective polarizing film 11 (with the transparent resin layer 3) of the present invention is formed on the other single side (the side having no protective film 2) of the polarizer 1 in the single-protective polarizing film 10. The transparent resin layer 3 is provided (directly). Further, as shown in FIG. 1 (B), a plurality of protective films 2 can be provided. In FIG. 1B, a single protective polarizing film (with a transparent resin layer) 11'provided with two protective films 2 and 2'is shown. The protective film 2 and the protective film 2'can be laminated by an adhesive layer 2a (in addition, an intervening layer such as an adhesive layer and an undercoat layer (primer layer)).

As described above, the thickness of the polarizer is X (μm) and the thickness of the transparent resin layer Y (μm) satisfies X ≦ 12, Y ≦ 15, 0.15 ≦ (Y / X) ≦ 3. Designed to do. From the viewpoint of suppressing defects caused by nanoslits generated in the polarizer, the value (Y / X) is preferably 0.24 or more. On the other hand, from the viewpoint of curl suppression, the value (Y / X) is preferably 0.8 or less, and more preferably 0.5 or less. The value (Y / X) is preferably 0.24 ≦ (Y / X) ≦ 0.8, and more preferably 0.24 ≦ (Y / X) ≦ 0.5. ..

Further, as shown in FIG. 2, the polarizing film 12 with an adhesive layer of the present invention has a single protective polarizing film (with a transparent resin layer) 11 and an adhesive layer 4. The pressure-sensitive adhesive layer 4 is provided on the side of the transparent resin layer 3 in FIG. 2 (A) and on the side of the protective film 2 in FIG. 2 (B). A separator 5 can be provided on the pressure-sensitive adhesive layer 4 of the polarizing film 12 with a pressure-sensitive pressure-sensitive adhesive layer of the present invention, and a surface protective film 6 can be provided on the opposite side thereof. In the polarizing film 12 with an adhesive layer of FIG. 2, a case where both the separator 5 and the surface protective film 6 are provided is shown. A polarizing film 12 with an adhesive layer having at least a separator 5 (furthermore, one having a surface protective film 6) can be used as a winding body, and as will be described later, for example, the separator 5 is unwound from the winding body. A method of bonding the polarizing film 12 with an adhesive layer conveyed by the above method to the surface of an image display panel via the adhesive layer 4 (hereinafter, also referred to as “roll-to-panel method”. It is advantageous for application to the specification No. 4406043). As the polarizing film with an adhesive layer, the embodiment shown in FIG. 2A is preferable from the viewpoint of suppressing warpage of the display panel after bonding, suppressing generation of nanoslits, and the like. The surface protective film 6 can be provided on the single protective polarizing film 10 and the single protective polarizing film (with a transparent resin layer) 11. In FIG. 2, the case where the single protective polarizing film (with transparent resin layer) 11 of FIG. 1 (A) is used is illustrated, but the single protective polarizing film (with transparent resin layer) of FIG. 1 (B) is used. 11'can also be used.

FIG. 3 is a conceptual diagram comparing the nanoslit a generated in the polarizer and the through crack b. FIG. 3A shows a nanoslit a formed in the polarizer 1, and FIG. 3B shows a through crack b formed in the polarizer 1. The nanoslit a is generated by a mechanical impact and is partially generated in the absorption axis direction of the polarizer 1. The nanoslit a cannot be confirmed at the beginning when it is generated, but it is in a thermal environment (for example, 80 ° C. or 60 ° C., At 90% RH), it can be confirmed by the spread in the width direction. On the other hand, it is considered that the nanoslit a does not have a progressive property extending in the absorption axis direction of the polarizer. Further, it is considered that the nanoslit a is generated regardless of the size of the polarizing film. The nanoslits a may occur independently or adjacent to each other. On the other hand, the through crack b is generated by a thermal shock (for example, a heat shock test). The through crack has a progressive property of extending in the absorption axis direction of the polarizing element in which the crack is generated. When the through crack b occurs, the stress in the periphery is released, so that the through crack does not occur adjacently.

FIG. 4 is an example of a photograph of a cross-sectional view of a single-protective polarizing film 10 or a single-protective polarizing film 11 with a transparent resin layer, which is involved in the generation, expansion, and repair of nanoslits a generated in a polarizer. FIG. 4A is an example of a single protective polarizing film 10 having the protective film 2 via the adhesive layer 2a on only one side of the polarizing element 1 and in the case where nanoslits are not generated. FIG. 4B is an example in which nanoslits a are generated in the one-sided protective polarizing film 10. Both FIGS. 4 (A) and 4 (B) are before heating. Further, FIG. 4C is an example of a photograph of a cross-sectional view after heating the one-sided protective polarizing film 10 in which the nanoslit a is generated. In FIG. 4C, it can be seen that the nanoslit a of the polarizer 1 is expanded by heating. On the other hand, FIG. 4D is an example of a photograph of a cross-sectional view of the single-protective polarizing film 11 having the transparent resin layer 3 formed on the single-protective polarizing film 10 in which the nanoslit a is generated. In FIG. 4D, it can be seen that the nanoslit a formed in the polarizer 1 is repaired (a') by the transparent resin layer 3. Further, FIG. 4 (E) is an example of a photograph of a cross-sectional view of the one-sided protective polarizing film 11 with the transparent resin layer formed on the transparent resin layer 3 after being heated. In FIG. 4 (E), it can be seen that the repaired (a') nanoslit does not expand after heating. FIG. 4 was cross-sectioned with a cross-session polisher or a microtome perpendicular to the absorption axis direction of the sample, and observed with a scanning electron microscope.

<Polarizer>
In the present invention, a polarizer having a thickness of 12 μm or less is used. The thickness of the polarizer is preferably 10 μm or less, more preferably 8 μm or less, further preferably 7 μm or less, and further preferably 6 μm or less from the viewpoint of thinning and suppressing the occurrence of through cracks. On the other hand, the thickness of the polarizer is preferably 2 μm or more, more preferably 3 μm or more. Such a thin polarizing element has less uneven thickness, excellent visibility, and less dimensional change, so that it has excellent durability against thermal shock.

As the polarizer, one using a polyvinyl alcohol-based resin is used. Examples of the polarizer include a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, and an ethylene-vinyl acetate copolymerization system partially saponified film, and a bicolor property of iodine or a bicolor dye. Examples thereof include a uniaxially stretched film by adsorbing a substance, a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol and a dehydrogenated product of polyvinyl chloride. Among these, a polarizer made of a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferable.

A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching it can be produced, for example, by dyeing polyvinyl alcohol by immersing it in an aqueous solution of iodine and stretching it 3 to 7 times its original length. If necessary, boric acid, zinc sulfate, zinc chloride and the like may be contained, or the mixture may be immersed in an aqueous solution such as potassium iodide. Further, if necessary, the polyvinyl alcohol-based film may be immersed in water and washed with water before dyeing. In addition to being able to clean the surface of the polyvinyl alcohol film and blocking inhibitors by washing the polyvinyl alcohol film with water, it also has the effect of preventing non-uniformity such as uneven dyeing by swelling the polyvinyl alcohol film. be. Stretching may be performed after dyeing with iodine, stretching while dyeing, or stretching and then dyeing with iodine. It can be stretched even in an aqueous solution such as boric acid or potassium iodide or in a water bath.

It is preferable that the polarizer contains boric acid from the viewpoint of stretch stability and optical durability. Further, the boric acid content contained in the polarizer is preferably 25% by weight or less, more preferably 20% by weight or less, based on the total amount of the polarizer from the viewpoint of suppressing the generation of through cracks and nanoslits and suppressing expansion. It is preferably 18% by weight or less, and more preferably 16% by weight or less. When the boric acid content in the polarizer exceeds 20% by weight, the shrinkage stress of the polarizer increases and through cracks are likely to occur even when the thickness of the polarizer is controlled to 10 μm or less, which is preferable. No. On the other hand, from the viewpoint of stretching stability and optical durability of the polarizer, the boric acid content with respect to the total amount of the polarizer is preferably 10% by weight or more, more preferably 12% by weight or more.

As a thin polarizer, typically
Japanese Patent No. 4751486,
Japanese Patent No. 4751481
Patent No. 4815544,
Japanese Patent No. 5048120,
Japanese Patent No. 5587517,
International Publication No. 2014/07759 Pamphlet,
International Publication No. 2014/077636 Pamphlet,
Etc., or the thin polarizing element obtained from the manufacturing method described in these.

The polarizer has optical characteristics represented by a simple substance transmittance T and a degree of polarization P of the following equation P> − (10 ^{0.929 T-42.4} -1) × 100 (where T <42.3). Or,
It is configured to satisfy the condition of P ≧ 99.9 (however, T ≧ 42.3). A polarizer configured to satisfy the above conditions primarily has the performance required for a display for a liquid crystal television using a large display element. Specifically, the contrast ratio is 1000: 1 or more and the maximum brightness is 500 cd / m ² or more. As another application, for example, it is bonded to the visual side of an organic EL display device.

On the other hand, a polarizer configured to satisfy the above conditions has a thickness of 10 μm or less because the constituent polymer (for example, a polyvinyl alcohol-based molecule) exhibits high orientation. The tensile breaking stress in the direction orthogonal to the absorption axis direction is significantly reduced. As a result, for example, when exposed to a mechanical impact exceeding the tensile breaking stress in the manufacturing process of the polarizing film, there is an extremely high possibility that nanoslits are generated in the absorption axis direction of the polarizer. Therefore, the present invention is particularly suitable for a single-protective polarizing film (or a polarizing film with an adhesive layer using the same) that employs the polarizer.

The thin polarizer is patented in Patent No. 4751486, in that it can be stretched at a high magnification and the polarization performance can be improved even in a manufacturing method including a step of stretching in a laminated state and a step of dyeing. Those obtained by a production method including a step of stretching in an aqueous boric acid solution as described in Japanese Patent No. 4751481 and Japanese Patent No. 4815544 are preferable, and particularly described in Japanese Patent No. 4751481 and Japanese Patent No. 4815544. It is preferably obtained by a production method including a step of auxiliary stretching in the air before stretching in a certain boric acid aqueous solution. These thin polarizers can be obtained by a production method including a step of stretching a polyvinyl alcohol-based resin (hereinafter, also referred to as PVA-based resin) layer and a resin base material for stretching in a laminated state and a step of dyeing. With this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without problems such as breakage due to stretching because it is supported by the stretching resin base material.

<Protective film>
As the material constituting the protective film, those having excellent transparency, mechanical strength, thermal stability, moisture blocking property, isotropic property and the like are preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, and styrene such as polystyrene and acrylonitrile-styrene copolymer (AS resin). Examples thereof include based polymers and polystyrene polymers. In addition, polyethylene, polypropylene, polyolefins having a cyclo- or norbornene structure, polyolefin-based polymers such as ethylene / propylene copolymers, vinyl chloride-based polymers, amide-based polymers such as nylon and aromatic polyamide, imide-based polymers, and sulfone-based polymers. , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, allylate polymer, polyoxymethylene polymer, epoxy polymer, or the above. Polymer blends and the like are also examples of polymers that form the protective film.

In addition, one or more kinds of arbitrary suitable additives may be contained in a protective film. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, a color retardant, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a colorant and the like. The content of the thermoplastic resin in the protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, still more preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. When the content of the thermoplastic resin in the protective film is 50% by weight or less, the high transparency inherent in the thermoplastic resin may not be sufficiently exhibited.

As the protective film, a retardation film, a brightness improving film, a diffusion film and the like can also be used. Examples of the retardation film include those having a frontal retardation of 40 nm or more and / or a thickness direction retardation of 80 nm or more. The front phase difference is usually controlled in the range of 40 to 200 nm, and the thickness direction phase difference is usually controlled in the range of 80 to 300 nm. When a retardation film is used as the protective film, the retardation film also functions as a polarizer protective film, so that the thickness can be reduced.

Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a thermoplastic resin film. The stretching temperature, stretching ratio, and the like are appropriately set depending on the retardation value, the film material, and the thickness.

The thickness of the protective film can be appropriately determined, but is generally about 1 to 500 μm in terms of workability such as strength and handleability, and thin layer property. In particular, 1 to 300 μm is preferable, and 5 to 200 μm is more preferable. In particular, when one protective film is used, the thickness is preferably 100 μm or less, more preferably 80 μm or less, and further preferably 60 μm or less from the viewpoint of thinning. Further, from the viewpoint of protecting the polarizing film from breakage or breakage, it is preferably 10 μm or more, and more preferably 20 μm or more. Further, when the thickness of the protective film is V (μm), mechanical stress is applied to the polarizing film in relation to the thickness X (μm) of the polarizer and the thickness Y (μm) of the transparent resin layer. From the viewpoint of suppressing the polarizer from breaking, it is preferable to satisfy 4X ≦ (Y + V), and further preferably 5X ≦ (Y + V).

Further, two protective films can be used. From the viewpoint of protecting the polarizing films from breakage and breakage, the total thickness of the two protective films is preferably 10 μm or more, more preferably 20 μm or more, and from the viewpoint of reducing the thickness of the single protective polarizing film. It is preferable to control the total thickness of each protective film to be 100 μm or less.

A functional layer such as a hard coat layer, an antireflection layer, an anti-sticking layer, a diffusion layer or an anti-glare layer can be provided on the surface of the protective film from which the polarizer is not adhered (particularly, the aspect of FIG. 1). The functional layers such as the hard coat layer, the antireflection layer, the sticking prevention layer, the diffusion layer and the antiglare layer can be provided on the protective film itself, or may be provided separately from the protective film. can.

<Intervening layer>
The protective film and the polarizer are laminated via an intervening layer such as an adhesive layer, an adhesive layer, and an undercoat layer (primer layer). At this time, it is desirable that both are laminated without an air gap by an intervening layer. The protective film and the polarizer are preferably laminated via an adhesive layer.

The adhesive layer is formed by the adhesive. The type of adhesive is not particularly limited, and various adhesives can be used. The adhesive layer is not particularly limited as long as it is optically transparent, and various forms such as water-based, solvent-based, hot-melt-based, and active energy ray-curable type are used as the adhesive. Alternatively, an active energy ray-curable adhesive is suitable.

Examples of the water-based adhesive include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based adhesives, and water-based polyesters. The water-based adhesive is usually used as an adhesive composed of an aqueous solution, and usually contains 0.5 to 60% by weight of a solid content. Of these, isocyanate-based adhesives and polyvinyl alcohol-based adhesives are preferable. A urethane-based resin layer is formed as an adhesive layer from the isocyanate-based adhesive.

The active energy ray-curable adhesive is an adhesive whose curing proceeds by active energy rays such as electron beam and ultraviolet rays (radical curing type, cationic curing type). For example, in the form of electron beam curing type and ultraviolet curing type. Can be used. As the active energy ray-curable adhesive, for example, a photoradical curable adhesive can be used. When a photoradical-curable active energy ray-curable adhesive is used as an ultraviolet curable type, the adhesive contains a radical-polymerizable compound and a photopolymerization initiator. For example, the radical-curable UV-curable adhesive is preferably a UV-curable acrylic resin, and the cationically curable UV-curable adhesive is preferably a UV-curable epoxy resin.

The adhesive coating method is appropriately selected depending on the viscosity of the adhesive and the desired thickness. Examples of the coating method include a reverse coater, a gravure coater (direct, reverse and offset), a bar reverse coater, a roll coater, a die coater, a bar coater, a rod coater and the like. In addition, a method such as a dipping method can be appropriately used for coating.

The thickness of the adhesive layer is preferably 0.1 μm or more and 5 μm or less, and a preferable range can be set depending on the type of the water-based adhesive or the active energy ray-curable adhesive. The thickness of 0.1 μm or more is preferable from the viewpoint of maintaining the adhesive force, and the thickness of 5 μm or less is preferable from the viewpoint of ensuring optical reliability. When a water-based adhesive or the like is used, the adhesive is preferably applied so that the thickness of the finally formed adhesive layer is 100 to 300 nm. The thickness of the adhesive layer is more preferably 100 to 250 nm. On the other hand, when an active energy ray-curable adhesive is used, the thickness of the adhesive layer is preferably 0.2 to 5 μm. It is more preferably 0.2 to 2 μm, still more preferably 0.5 to 1.5 μm.

Further, the adhesive layer preferably has a compressive elastic modulus at 80 ° C. of 0.1 GPa or more and 10 GPa or less in order to suppress through cracks while relaxing the force applied to the polarizer. It is preferable that the compressive elastic modulus is 0.1 GPa or more in order to absorb impact and secure crack resistance (suppression of occurrence of nanoslits and suppression of through cracks), and it is preferable that the compressive elastic modulus is 10 GPa or less. It is preferable from the viewpoint that it cannot suppress the penetration crack and suppresses the through crack. In particular, when the adhesive layer is formed of an active energy ray-curable adhesive, the compressive elastic modulus is preferably 1 GPa or more, more preferably 3 GPa or more. On the other hand, the compressive elastic modulus is preferably 8 GPa or less.

When laminating the polarizer and the protective film, an easy-adhesion layer can be provided between the protective film and the adhesive layer. The easy-adhesion layer can be formed of, for example, various resins having a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone-based material, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, and the like. These polymer resins may be used alone or in combination of two or more. Further, other additives may be added to form the easy-adhesion layer. Specifically, a tackifier, an ultraviolet absorber, an antioxidant, a stabilizer such as a heat-resistant stabilizer, or the like may be used.

The easy-adhesive layer is usually provided in advance on the protective film, and the easy-adhesive layer side of the protective film and the polarizer are laminated by the adhesive layer. The easy-adhesive layer is formed by applying a material for forming the easy-adhesive layer onto a protective film by a known technique and drying it. The material for forming the easy-adhesion layer is usually adjusted as a solution diluted to an appropriate concentration in consideration of the thickness after drying, the smoothness of coating, and the like. The thickness of the easy-adhesion layer after drying is preferably 0.01 to 5 μm, more preferably 0.02 to 2 μm, and further preferably 0.05 to 1 μm. A plurality of easy-adhesive layers can be provided, but even in this case, it is preferable that the total thickness of the easy-adhesive layers is within the above range.

The pressure-sensitive adhesive layer is formed from the pressure-sensitive adhesive. Various adhesives can be used as the adhesive, for example, rubber adhesive, acrylic adhesive, silicone adhesive, urethane adhesive, vinyl alkyl ether adhesive, polyvinylpyrrolidone adhesive, poly. Examples include acrylamide-based adhesives and cellulose-based adhesives. A sticky base polymer is selected according to the type of the pressure-sensitive adhesive. Among the above-mentioned adhesives, acrylic adhesives are preferably used because they are excellent in optical transparency, exhibit appropriate wettability, cohesiveness and adhesive properties, and are excellent in weather resistance and heat resistance. NS.

The undercoat layer (primer layer) is formed to improve the adhesion between the polarizer and the protective film. The material constituting the primer layer is not particularly limited as long as it is a material that exhibits a certain degree of strong adhesion to both the base film and the polyvinyl alcohol-based resin layer. For example, a thermoplastic resin having excellent transparency, thermal stability, stretchability, etc. is used. Examples of the thermoplastic resin include acrylic resins, polyolefin resins, polyester resins, polyvinyl alcohol resins, and mixtures thereof.

Further, when at least two protective films are used, it is preferable that the protective films are laminated via an adhesive layer or an adhesive layer. The thickness of the adhesive layer is preferably 0.1 μm or more, more preferably 0.2 μm or more from the viewpoint of adhesive strength. On the other hand, from the viewpoint of thinning, the thickness of the adhesive layer is preferably 5 μm or less, more preferably 2 μm or less. When an adhesive is used for laminating each protective film, the thickness is preferably 2 μm or more from the viewpoint of adhesive strength. On the other hand, from the viewpoint of thinning, the thickness of the pressure-sensitive adhesive layer is preferably 20 μm or less.

<Transparent resin layer>
The transparent resin layer is provided on the other side of the polarizer (the surface on which the protective film is not laminated) in the one-sided protective polarizing film in which the protective film is provided on only one side of the polarizer. In the present invention, the transparent resin layer preferably has a compressive elastic modulus of 0.1 GPa or more at 80 ° C. Even if nanoslits are generated in the polarizer due to mechanical impact and the nanoslits try to widen in the width direction in a thermal environment, the compressive elastic modulus of the transparent resin layer at 80 ° C. is controlled to 0.1 GPa or more. Even in a thermal environment, the mechanical holding capacity of the transparent resin layer can be maintained, and the nanoslits can be suppressed from expanding in the width direction. The compressive elastic modulus of the transparent resin layer is preferably 0.5 GPa or more, more preferably 2 GPa or more, further 3 GPa or more, further 5 GPa or more, further 6 GPa or more, and further preferably 10 GPa or more. The compressive elastic modulus of the transparent resin layer can be adjusted by selecting the material. The compressive elastic modulus of the transparent resin layer at 80 ° C. is a value measured based on the description of Examples.

The thickness of the transparent resin layer (Y) is 15 μm or less from the viewpoint of thinning and optical reliability. Further, when the transparent resin layer becomes thick, the one-sided protective polarizing film tends to be curled after being stored. The thickness (Y) of the transparent resin layer is preferably 12 μm or less, more preferably 5 μm or less, and further preferably 1.5 μm or less. On the other hand, the thickness (Y) of the transparent resin layer is preferably 0.2 μm or more, more preferably 0.5 μm or more, and further preferably 0.6 μm or more from the viewpoint of the expansion suppressing effect of the nanoslit. Further, it is preferably 0.8 μm or more. The thickness (Y) of the transparent resin layer is controlled so as to satisfy 0.15 ≦ (Y / X) ≦ 3 in relation to the thickness X (μm) of the polarizer.

The transparent resin layer can be formed from a curable forming material containing a curable component. The curable component can be roughly classified into an active energy ray-curable type such as an electron beam-curable type, an ultraviolet-curable type, and a visible light-curable type, and a thermosetting type. Furthermore, the ultraviolet curable type and the visible light curable type can be classified into a radical polymerization curable type and a cationic polymerization curable type. In the present invention, active energy rays having a wavelength range of 10 nm to less than 380 nm are referred to as ultraviolet rays, and active energy rays having a wavelength range of 380 nm to 800 nm are referred to as visible light. The radical polymerization curable component can be used as a thermosetting curable component.

≪Radical polymerization curing type forming material≫
Examples of the curable component include radically polymerizable compounds. Examples of the radically polymerizable compound include compounds having a radically polymerizable functional group of a carbon-carbon double bond such as a (meth) acryloyl group and a vinyl group. As these curable components, either a monofunctional radical-polymerizable compound or a bifunctional or higher-functional polyfunctional radical-polymerizable compound can be used. In addition, these radically polymerizable compounds may be used alone or in combination of two or more. As these radically polymerizable compounds, for example, compounds having a (meth) acryloyl group are suitable. In addition, in this invention, (meth) acryloyl means acryloyl group and / or methacryloyl group, and "(meth)" has the same meaning below.

≪Monofunctional radical polymerizable compound≫
Examples of the monofunctional radically polymerizable compound include a (meth) acrylamide derivative having a (meth) acrylamide group. The (meth) acrylamide derivative is preferable in terms of ensuring adhesion to the polarizer and in terms of high polymerization rate and excellent productivity. Specific examples of the (meth) acrylamide derivative include N-methyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, and N. N-alkyl group-containing (meth) acrylamide derivatives such as −butyl (meth) acrylamide, N-hexyl (meth) acrylamide; N-methylol (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-methylol-N- N-Hydroxyalkyl group-containing (meth) acrylamide derivatives such as propane (meth) acrylamide; N-aminoalkyl group-containing (meth) acrylamide derivatives such as aminomethyl (meth) acrylamide and aminoethyl (meth) acrylamide; N-methoxymethyl N-alkoxy group-containing (meth) acrylamide derivatives such as acrylamide and N-ethoxymethylacrylamide; N-mercaptoalkyl group-containing (meth) acrylamide derivatives such as mercaptomethyl (meth) acrylamide and mercaptoethyl (meth) acrylamide; Be done. Examples of the heterocyclic (meth) acrylamide derivative in which the nitrogen atom of the (meth) acrylamide group forms a heterocycle include N-acrylloylmorpholine, N-acrylloylpiperidin, N-methacryloylpiperidin, and N-acrylloylpyridine. And so on.

Among the (meth) acrylamide derivatives, an N-hydroxyalkyl group-containing (meth) acrylamide derivative is preferable, and N-hydroxyethyl (meth) acrylamide is particularly preferable, from the viewpoint of adhesion to a polarizer.

In addition, examples of the monofunctional radically polymerizable compound include various (meth) acrylic acid derivatives having a (meth) acryloyloxy group. Specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, 2-methyl-2-nitropropyl (meth) acrylate, n-butyl ( Meta) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, t-pentyl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-Dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, 4-methyl-2-propylpentyl ( Examples thereof include (meth) acrylic acid (1-20 carbon atoms) alkyl esters such as meta) acrylate and n-octadecyl (meth) acrylate.

Further, as the (meth) acrylic acid derivative, for example, cycloalkyl (meth) acrylate such as cyclohexyl (meth) acrylate and cyclopentyl (meth) acrylate;
Aralkyl (meth) acrylates such as benzyl (meth) acrylate;
2-Isobornyl (meth) acrylate, 2-norbornene methyl (meth) acrylate, 5-norbornene-2-yl-methyl (meth) acrylate, 3-methyl-2-norbornenylmethyl (meth) acrylate, dicyclo Polycyclic (meth) acrylates such as pentenyl (meth) acrylicate, dicyclopentenyloxyethyl (meth) acrylicate, dicyclopentanyl (meth) acrylicate, etc.;
2-Methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethylcarbitol (meth) acrylate, phenoxyethyl (meth) Examples thereof include alkoxy groups such as acrylate and alkylphenoxy polyethylene glycol (meth) acrylate, or phenoxy group-containing (meth) acrylates.

Examples of the (meth) acrylic acid derivative include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-. Hydroxyalkyl (meth) acrylates such as hydroxybutyl (meth) acrylates, 6-hydroxyhexyl (meth) acrylates, 8-hydroxyoctyl (meth) acrylates, 10-hydroxydecyl (meth) acrylates, and 12-hydroxylauryl (meth) acrylates. Or, hydroxyl group-containing (meth) acrylates such as [4- (hydroxymethyl) cyclohexyl] methyl acrylate, cyclohexanedimethanol mono (meth) acrylate, and 2-hydroxy-3-phenoxypropyl (meth) acrylate;
Epoxy group-containing (meth) acrylates such as glycidyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate glycidyl ether;
2,2,2-trifluoroethyl (meth) acrylate, 2,2,2-trifluoroethyl ethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) ) Halogen-containing (meth) acrylates such as acrylates, heptadecafluorodecyl (meth) acrylates, 3-chloro-2-hydroxypropyl (meth) acrylates;
Alkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate;
3-Oxetanylmethyl (meth) acrylate, 3-methyl-oxetanylmethyl (meth) acrylate, 3-ethyl-oxetanylmethyl (meth) acrylate, 3-butyl-oxetanylmethyl (meth) acrylate, 3-hexyluoxetanylmethyl (meth) ) Oxetane group-containing (meth) acrylate such as acrylate;
(Meta) acrylates having a heterocycle such as tetrahydrofurfuryl (meth) acrylate and butyrolactone (meth) acrylate, neopentyl glycol (meth) acrylic acid adduct of hydroxypivalate, p-phenylphenol (meth) acrylate, etc. Can be mentioned.

Examples of the monofunctional radically polymerizable compound include carboxyl group-containing monomers such as (meth) acrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid.

Examples of the monofunctional radically polymerizable compound include lactam-based vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazin, and vinylpyrazine. Examples thereof include vinyl-based monomers having a nitrogen-containing heterocycle such as vinylpyrrole, vinylimidazole, vinyloxazole, and vinylmorpholin.

Further, as the monofunctional radically polymerizable compound, a radically polymerizable compound having an active methylene group can be used. A radically polymerizable compound having an active methylene group is a compound having an active double bond group such as a (meth) acrylic group at the terminal or in the molecule and having an active methylene group. Examples of the active methylene group include an acetoacetyl group, an alkoxymalonyl group, a cyanoacetyl group and the like. The active methylene group is preferably an acetoacetyl group. Specific examples of the radically polymerizable compound having an active methylene group include 2-acetoacetoxyethyl (meth) acrylate, 2-acetoacetoxypropyl (meth) acrylate, 2-acetacetoxy-1-methylethyl (meth) acrylate and the like. Acetoacetoxyalkyl (meth) acrylate; 2-ethoxymalonyloxyethyl (meth) acrylate, 2-cyanoacetoxyethyl (meth) acrylate, N- (2-cyanoacetoxyethyl) acrylamide, N- (2-propionylacetoxybutyl) Examples thereof include acrylamide, N- (4-acetoacetoxymethylbenzyl) acrylamide, N- (2-acetoacetylaminoethyl) acrylamide and the like. The radically polymerizable compound having an active methylene group is preferably acetoacetoxyalkyl (meth) acrylate.

≪Polyfunctional radical polymerizable compound≫
Examples of the bifunctional or higher polyfunctional radical polymerizable compound include tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and 1,9. -Nonandiol di (meth) acrylate, 1,10-decanediol diacrylate, 2-ethyl-2-butylpropanediol di (meth) acrylate, bisphenol A di (meth) acrylate, bisphenol A ethylene oxide adduct di (meth) ) Acrylate, bisphenol A propylene oxide adduct di (meth) acrylate, bisphenol A diglycidyl ether di (meth) acrylate, neopentyl glycol di (meth) acrylate, tricyclodecanedimethanol di (meth) acrylate, cyclic tri Methylolpropanformal (meth) acrylate, dioxane glycol di (meth) acrylate, trimethylpropantri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate , Dipentaerythritol hexa (meth) acrylate, esterified product of (meth) acrylic acid such as EO-modified diglycerin tetra (meth) acrylate and polyhydric alcohol, 9,9-bis [4- (2- (meth) acryloyl) Oxyethoxy) phenyl] Fluolene can be mentioned. Specific examples include Aronix M-220, M-306 (manufactured by Toagosei Co., Ltd.), Light Acrylate 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), Light Acrylate DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), Light Acrylate DCP- Examples thereof include A (manufactured by Kyoeisha Chemical Co., Ltd.), SR-531 (manufactured by Sartomer), and CD-536 (manufactured by Sartomer). Further, if necessary, various epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, various (meth) acrylate-based monomers and the like can be mentioned.

As the radically polymerizable compound, it is preferable to use a monofunctional radically polymerizable compound and a polyfunctional radically polymerizable compound in combination from the viewpoint of achieving both adhesion to a polarizer and optical durability. Usually, it is preferable to use the monofunctional radical polymerizable compound in an amount of 3 to 80% by weight and the polyfunctional radical polymerizable compound in an amount of 20 to 97% by weight based on 100% by weight of the radically polymerizable compound.

<< Aspects of radical polymerization curable forming material >>
The radical polymerization curing type forming material can be used as an active energy ray curing type or thermosetting type forming material. When an electron beam or the like is used for the active energy ray, the active energy ray-curable forming material does not need to contain a photopolymerization initiator, but when ultraviolet rays or visible light are used for the active energy ray, the active energy ray-curable forming material does not need to contain a photopolymerization initiator. It preferably contains a photopolymerization initiator. On the other hand, when the curable component is used as a thermosetting component, the forming material preferably contains a thermopolymerization initiator.

≪Photopolymerization initiator≫
When a radically polymerizable compound is used, the photopolymerization initiator is appropriately selected by the active energy ray. When curing by ultraviolet rays or visible light, a photopolymerization initiator that cleaves ultraviolet rays or visible light is used. Examples of the photopolymerization initiator include benzophenone compounds such as benzyl, benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone; 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2). Aromatic ketone compounds such as -propyl) ketone, α-hydroxy-α, α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, α-hydroxycyclohexylphenylketone; methoxyacetophenone, 2,2-dimethoxy- Acetphenone compounds such as 2-phenylacetophenylone, 2,2-diethoxyacetophenone, 2-methyl-1- [4- (methylthio) -phenyl] -2-morpholinopropane-1; benzoine methyl ether, Benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, anisoin methyl ether; aromatic ketal compounds such as benzyl dimethyl ketal; aromatic sulfonyl chlorides such as 2-naphthalene sulfonyl chloride. System compounds; Photoactive oxime compounds such as 1-phenone-1,1-propanedione-2- (o-ethoxycarbonyl) oxime; thioxanson, 2-chlorothioxanson, 2-methylthioxanson, 2,4- Thioxanthone compounds such as dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone; camphorquinone; halogenated Examples thereof include ketones; acylphosphinoxides; and acylphosphonates.

The blending amount of the photopolymerization initiator is 20 parts by weight or less with respect to 100 parts by weight of the total amount of the curable component (radical polymerizable compound). The blending amount of the photopolymerization initiator is preferably 0.01 to 20 parts by weight, more preferably 0.05 to 10 parts by weight, and further preferably 0.1 to 5 parts by weight.

Further, when the curable forming material for a polarizing film of the present invention is used in a visible light curable type containing a radically polymerizable compound as a curable component, a photopolymerization initiator having high sensitivity to light of 380 nm or more is used. It is preferable to use it. A photopolymerization initiator having high sensitivity to light of 380 nm or more will be described later.

（式中、Ｒ^１およびＲ^２は−Ｈ、−ＣＨ_２ＣＨ_３、−ｉＰｒまたはＣｌを示し、Ｒ^１およびＲ^２は同一または異なっても良い）を単独で使用するか、あるいは一般式（１）で表される化合物と後述する３８０ｎｍ以上の光に対して高感度な光重合開始剤とを併用することが好ましい。一般式（１）で表される化合物を使用した場合、３８０ｎｍ以上の光に対して高感度な光重合開始剤を単独で使用した場合に比べて密着性に優れる。一般式（１）で表される化合物の中でも、Ｒ^１およびＲ^２が−ＣＨ_２ＣＨ_３であるジエチルチオキサントンが特に好ましい。当該形成材中の一般式（１）で表される化合物の組成比率は、硬化性成分の全量１００重量部に対して、０．１〜５重量部であることが好ましく、０．５〜４重量部であることがより好ましく、０．９〜３重量部であることがさらに好ましい。 The photopolymerization initiator is a compound represented by the following general formula (1);

(In the formula, R ¹ and R ² indicate -H, -CH ₂ CH ₃ , -iPr or Cl, and R ¹ and R ² may be the same or different), or the general formula (in the formula) may be used alone. It is preferable to use the compound represented by 1) in combination with a photopolymerization initiator having high sensitivity to light of 380 nm or more, which will be described later. When the compound represented by the general formula (1) is used, the adhesion is excellent as compared with the case where a photopolymerization initiator having high sensitivity to light of 380 nm or more is used alone. Among the compounds represented by the general formula (1), ^{diethylthioxanthone in which R 1} and R ² are −CH ₂ CH ₃ is particularly preferable. The composition ratio of the compound represented by the general formula (1) in the forming material is preferably 0.1 to 5 parts by weight, preferably 0.5 to 4 parts by weight, based on 100 parts by weight of the total amount of the curable component. It is more preferably parts by weight, and even more preferably 0.9 to 3 parts by weight.

In addition, it is preferable to add a polymerization initiation aid as needed. Examples of the polymerization initiator include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, and isoamyl 4-dimethylaminobenzoate. , And ethyl 4-dimethylaminobenzoate is particularly preferable. When a polymerization initiation aid is used, the amount added is usually 0 to 5 parts by weight, preferably 0 to 4 parts by weight, and most preferably 0 to 3 parts by weight, based on 100 parts by weight of the total amount of the curable component. be.

In addition, a known photopolymerization initiator can be used in combination if necessary. Since the protective film having UV absorption ability does not transmit light of 380 nm or less, it is preferable to use a photopolymerization initiator having high sensitivity to light of 380 nm or more as the photopolymerization initiator. Specifically, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 , 2- (Dimethylamino) -2-[(4-Methylphenyl) Methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, 2,4,6-trimethylbenzoyl-diphenyl-phosphine Oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (η5-2,4-cyclopentadiene-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-) 1-yl) -phenyl) titanium and the like can be mentioned.

（式中、Ｒ^３、Ｒ^４およびＲ^５は−Ｈ、−ＣＨ_３、−ＣＨ_２ＣＨ_３、−ｉＰｒまたはＣｌを示し、Ｒ^３、Ｒ^４およびＲ^５は同一または異なっても良い）を使用することが好ましい。一般式（２）で表される化合物としては、市販品でもある２−メチル−１−（４−メチルチオフェニル）−２−モルフォリノプロパン−１−オン（商品名：ＩＲＧＡＣＵＲＥ９０７ メーカー：ＢＡＳＦ）が好適に使用可能である。その他、２−ベンジル−２−ジメチルアミノ−１−（４−モルフォリノフェニル）−ブタノン−１（商品名：ＩＲＧＡＣＵＲＥ３６９ メーカー：ＢＡＳＦ）、２−（ジメチルアミノ）−２−［（４−メチルフェニル）メチル］−１−［４−（４−モルホリニル）フェニル］−１−ブタノン（商品名：ＩＲＧＡＣＵＲＥ３７９ メーカー：ＢＡＳＦ）が感度が高いため好ましい。 In particular, as the photopolymerization initiator, in addition to the photopolymerization initiator of the general formula (1), a compound represented by the following general formula (2);

(In the formula, R ³ , R ⁴ and R ⁵ indicate -H, -CH ₃ , -CH ₂ CH ₃ , -iPr or Cl, and R ³ , R ⁴ and R ⁵ may be the same or different). It is preferable to use it. As the compound represented by the general formula (2), 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one (trade name: IRGACURE907 manufacturer: BASF), which is also a commercially available product, is preferable. Can be used for. In addition, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1 (trade name: IRGACURE369 manufacturer: BASF), 2- (dimethylamino) -2-[(4-methylphenyl) Methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone (trade name: IRGACURE379 manufacturer: BASF) is preferable because of its high sensitivity.

<Radical polymerizable compound having an active methylene group and a radical polymerization initiator having a hydrogen abstraction action>
In the above-mentioned active energy ray-curable forming material, when a radical polymerizable compound having an active methylene group is used as the radical polymerizable compound, it is preferably used in combination with a radical polymerization initiator having a hydrogen abstraction action.

Examples of the radical polymerization initiator having a hydrogen abstraction action include a thioxanthone-based radical polymerization initiator and a benzophenone-based radical polymerization initiator. The radical polymerization initiator is preferably a thioxanthone-based radical polymerization initiator. Examples of the thioxanthone-based radical polymerization initiator include compounds represented by the above general formula (1). Specific examples of the compound represented by the general formula (1) include thioxanthone, dimethylthioxanthone, diethylthioxanthone, isopropylthioxanthone, chlorothioxanthone and the like. Among the compounds represented by the general formula (1), ^{diethylthioxanthone in which R 1} and R ² are −CH ₂ CH ₃ is particularly preferable.

When the above active energy ray-curable forming material contains a radical polymerizable compound having an active methylene group and a radical polymerization initiator having a hydrogen abstraction action, when the total amount of the curable component is 100% by weight, It is preferable to contain 1 to 50% by weight of the radically polymerizable compound having an active methylene group and 0.1 to 10 parts by weight of the radical polymerization initiator with respect to 100 parts by weight of the total amount of the curable component.

≪Thermal polymerization initiator≫
As the thermal polymerization initiator, it is preferable that the polymerization is not initiated by thermal cleavage when the adhesive layer is formed. For example, the thermal polymerization initiator preferably has a 10-hour half-life temperature of 65 ° C. or higher, more preferably 75 to 90 ° C. The half-life is an index showing the decomposition rate of the polymerization initiator, and means the time until the residual amount of the polymerization initiator is halved. The decomposition temperature for obtaining a half-life at an arbitrary time and the half-life time at an arbitrary temperature are described in the manufacturer's catalog, etc. For example, "Organic peroxide catalog 9th edition" of Nippon Oil & Fats Co., Ltd. (May 2003) ”and so on.

Examples of the thermal polymerization initiator include lauroyl peroxide (10-hour half-life temperature: 64 ° C.), benzoyl peroxide (10-hour half-life temperature: 73 ° C.), and 1,1-bis (t-butylperoxy) -3. , 3,5-trimethylcyclohexane (10-hour half-life temperature: 90 ° C.), di (2-ethylhexyl) peroxydicarbonate (10-hour half-life temperature: 49 ° C.), di (4-t-butylcyclohexyl) Peroxydicarbonate, di-sec-butylperoxydicarbonate (10-hour half-life temperature: 51 ° C.), t-butylperoxyneodecanoate (10-hour half-life temperature: 48 ° C.), t-hexylperoxy Pivalate, t-butylperoxy pivalate, dilauroyl peroxide (10-hour half-life temperature: 64 ° C), di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2 -Ethylhexanoate (10-hour half-life temperature: 66 ° C.), di (4-methylbenzoyl) peroxide, dibenzoyl peroxide (10-hour half-life temperature: 73 ° C.), t-butylperoxyisobutyrate (10) Time half-life temperature: 81 ° C.), organic peroxides such as 1,1-di (t-hexylperoxy) cyclohexane.

Examples of the thermal polymerization initiator include 2,2'-azobisisobutyronitrile (10-hour half-life temperature: 67 ° C.) and 2,2'-azobis (2-methylbutyronitrile) (10-hour). Examples thereof include azo compounds such as half-life temperature: 67 ° C.) and 1,1-azobis-cyclohexane-1-carbonitrile (10-hour half-life temperature: 87 ° C.).

The blending amount of the thermal polymerization initiator is 0.01 to 20 parts by weight with respect to 100 parts by weight of the total amount of the curable component (radical polymerizable compound). The blending amount of the thermal polymerization initiator is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 3 parts by weight.

≪Cationic polymerization curing type forming material≫
Examples of the curable component of the cationic polymerization curable forming material include compounds having an epoxy group and an oxetanyl group. The compound having an epoxy group is not particularly limited as long as it has at least two epoxy groups in the molecule, and various generally known curable epoxy compounds can be used. Preferred epoxy compounds include compounds having at least two epoxy groups and at least one aromatic ring in the molecule (aromatic epoxy compounds) and at least one of them having at least two epoxy groups in the molecule. Examples thereof include a compound (alicyclic epoxy compound) formed between two adjacent carbon atoms constituting an alicyclic ring.

<Other ingredients>
The curable forming material according to the present invention preferably contains the following components.

<Acrylic oligomer>
The active energy ray-curable forming material according to the present invention can contain an acrylic oligomer obtained by polymerizing a (meth) acrylic monomer in addition to the curable component according to the radically polymerizable compound. By containing an acrylic oligomer in the active energy ray-curable forming material, the curing shrinkage when irradiating and curing the transparent resin layer with active energy rays is reduced, and the transparent resin layer is adhered to a polarizer or the like. The interfacial stress with the body can be reduced. As a result, it is possible to suppress a decrease in the adhesiveness between the adhesive layer and the adherend. In order to sufficiently suppress curing shrinkage, the content of the acrylic oligomer is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, based on 100 parts by weight of the total amount of the curable component. preferable. If the content of the acrylic oligomer in the forming material is too large, the reaction rate when the forming material is irradiated with active energy rays is drastically reduced, which may result in poor curing. On the other hand, it is preferable to contain 3 parts by weight or more of the acrylic oligomer, and more preferably 5 parts by weight or more, based on 100 parts by weight of the total amount of the curable component.

Since the active energy ray-curable forming material preferably has a low viscosity in consideration of workability and uniformity during coating, an acrylic oligomer obtained by polymerizing a (meth) acrylic monomer also has a low viscosity. Is preferable. As the acrylic oligomer having a low viscosity and capable of preventing the curing shrinkage of the transparent resin layer, those having a weight average molecular weight (Mw) of 15,000 or less are preferable, those having a weight average molecular weight (Mw) of 15,000 or less are more preferable, and those having a weight average molecular weight (Mw) of 5,000 or less are particularly preferable. preferable. On the other hand, in order to sufficiently suppress the curing shrinkage of the transparent resin layer, the weight average molecular weight (Mw) of the acrylic oligomer is preferably 500 or more, more preferably 1000 or more, and 1500 or more. Is particularly preferable. Specific examples of the (meth) acrylic monomer constituting the acrylic oligomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and 2-methyl-. 2-Nitropropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, S-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, t-pentyl (Meta) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethylbutyl (meth) acrylate, n-hexyl (meth) acrylate, cetyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl ( (Meta) acrylic acid (1-20 carbon atoms) alkyl esters such as meth) acrylates, 4-methyl-2-propylpentyl (meth) acrylates, N-octadecyl (meth) acrylates, and more, for example, cycloalkyl (meth) acrylates. ) Acrylate (eg, cyclohexyl (meth) acrylate, cyclopentyl (meth) acrylate, etc.), aralkyl (meth) acrylate (eg, benzyl (meth) acrylate, etc.), polycyclic (meth) acrylate (eg, 2-isobornyl (meth) acrylate, etc.) ) Acrylate, 2-norbornylmethyl (meth) acrylate, 5-norbornen-2-yl-methyl (meth) acrylate, 3-methyl-2-norbornylmethyl (meth) acrylate, etc.), hydroxyl group-containing (meth) ) Acrylate esters (eg, hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2,3-dihydroxypropylmethyl-butyl (meth) methacrylate, etc.), alkoxy group- or phenoxy group-containing (meth) acrylic. Acid esters (2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxymethoxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethylcarbitol (meth) acrylate, phenoxy Ethyl (meth) acrylates, etc.), epoxy group-containing (meth) acrylic acids (eg, glycidyl (meth) acrylates, etc.), halogen-containing (meth) acrylic acids (eg, 2,2,2-trifluoroethyl) (Meta) acrylate, 2,2,2- Trifluoroethyl ethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, etc.), alkylaminoalkyl (meth) Examples include acrylates (eg, dimethylaminoethyl (meth) acrylate, etc.). These (meth) acrylates can be used alone or in combination of two or more. Specific examples of the acrylic oligomer include "ARUFON" manufactured by Toagosei Co., Ltd., "Actflow" manufactured by Soken Chemical Co., Ltd., and "JONCRYL" manufactured by BASF Japan Ltd.

<Photoacid generator>
The active energy ray-curable forming material can contain a photoacid generator. When the active energy ray-curable forming material contains a photoacid generator, the water resistance and durability of the transparent resin layer can be dramatically improved as compared with the case where the photoacid generator is not contained. The photoacid generator can be represented by the following general formula (3).

（ただし、Ｌ^＋は、任意のオニウムカチオンを表す。また、Ｘ⁻は、ＰＦ６_６ ⁻、ＳｂＦ_６ ⁻、ＡｓＦ_６ ⁻、ＳｂＣｌ_６ ⁻、ＢｉＣｌ_５ ⁻、ＳｎＣｌ_６ ⁻、ＣｌＯ_４ ⁻、ジチオカルバメートアニオン、ＳＣＮ−よりからなる群より選択されるカウンターアニオンを表す。） General formula (3)

(However, L ⁺ represents an arbitrary onium cation. X ⁻ is PF6 ₆ ⁻ , SbF ₆ ⁻ , AsF ₆ ⁻ , SbCl ₆ ⁻ , BiCl ₅ ⁻ , SnCl ₆ ⁻ , ClO ₄ ⁻ , dithiocarbamate. Represents a counter anion selected from the group consisting of anions and SCN-).

Specific examples of preferred onium salts constituting the photoacid ^{_{generator, PF 6 -, SbF 6 -}} , AsF 6 -, SbCl 6 -, BiCl 5 -, SnCl 6 -, ClO 4 -, dithiocarbamate anion, SCN ^- It is an onium salt composed of more selected anions.

Specifically, "Cyracure UVI-6992", "Cyracure UVI-6974" (all manufactured by Dow Chemical Japan Co., Ltd.), "Adeka Putmer SP150", "Adeka Putmer SP152", "Adeka Putmer" SP170 "," ADEKA PUTMER SP172 "(above, ADEKA Corporation)," IRGACURE250 "(manufactured by Ciba Specialty Chemicals)," CI-5102 "," CI-2855 "(above, manufactured by Nippon Soda), "Sun Aid SI-60L", "Sun Aid SI-80L", "Sun Aid SI-100L", "Sun Aid SI-110L", "Sun Aid SI-180L" (all manufactured by Sanshin Kagaku Co., Ltd.), "CPI-100P", "CPI-100A" (all manufactured by Sun Appro Co., Ltd.), "WPI-069", "WPI-113", "WPI-116", "WPI-041", "WPI-044", "WPI-054", "WPI-055", "WPAG-281", "WPAG-567", and "WPAG-596" (all manufactured by Wako Pure Chemical Industries, Ltd.) are mentioned as preferable specific examples of the photoacid generator.

The content of the photoacid generator is 10 parts by weight or less, preferably 0.01 to 10 parts by weight, and 0.05 to 5 parts by weight with respect to 100 parts by weight of the total amount of the curable component. It is more preferable, and it is particularly preferable that it is 0.1 to 3 parts by weight.

≪Photocationic polymerization initiator≫
The cationic polymerization curable forming material contains the epoxy compound and the oxetane compound described above as curable components, and since these are both cured by cationic polymerization, a photocationic polymerization initiator is blended. This photocationic polymerization initiator generates a cationic species or Lewis acid by irradiation with active energy rays such as visible light, ultraviolet rays, X-rays, and electron beams, and initiates a polymerization reaction of an epoxy group or an oxetanyl group.

The transparent resin layer is formed by the curing type forming material by applying a curing type forming material on the surface of the polarizer and then curing.

The polarizer may be subjected to a surface modification treatment before the above-mentioned curable forming material is applied. Specific treatments include corona treatment, plasma treatment, and saponification treatment.

The coating method of the curable forming material is appropriately selected depending on the viscosity of the curable forming material and the target thickness. Examples of the coating method include a reverse coater, a gravure coater (direct, reverse and offset), a bar reverse coater, a roll coater, a die coater, a bar coater, a rod coater and the like. In addition, a method such as a dipping method can be appropriately used for coating.

<Hardening of forming material>
The curable type forming material is used as an active energy ray curable type forming material or a thermosetting type forming material. The active energy ray-curable forming material can be used in the form of electron beam-curable type, ultraviolet-curable type, and visible light-curable type. From the viewpoint of productivity, the active energy ray-curable forming material is preferable to the heat-curing type forming material, and the active energy ray-curable forming material is a visible light-curing type forming material. It is preferable from the viewpoint of productivity.

≪Active energy ray curing type≫
In the active energy ray-curable forming material, after coating the polarizer with the active energy ray-curable forming material, the active energy ray-curable forming material is irradiated with active energy rays (electron beam, ultraviolet rays, visible light, etc.) to obtain the active energy ray-curable forming material. It cures to form a transparent resin layer. The irradiation direction of the active energy rays (electron beam, ultraviolet rays, visible rays, etc.) can be any suitable direction. Preferably, the irradiation is performed from the transparent resin layer side.

≪Electron beam curing type≫
In the electron beam curing type, any appropriate conditions can be adopted as the electron beam irradiation conditions as long as the active energy ray curing type forming material can be cured. For example, in electron beam irradiation, the acceleration voltage is preferably 5 kV to 300 kV, and more preferably 10 kV to 250 kV. If the acceleration voltage is less than 5 kV, the electron beam may not reach the deepest part of the transparent resin layer and curing may be insufficient. If the acceleration voltage exceeds 300 kV, the penetrating power through the sample is too strong, and the protective film or polarizer May damage the. The irradiation dose is 5 to 100 kGy, more preferably 10 to 75 kGy. If the irradiation dose is less than 5 kGy, the adhesive will be insufficiently cured, and if it exceeds 100 kGy, the protective film and polarizer will be damaged, mechanical strength will decrease and yellowing will occur, and the specified optical characteristics may be obtained. Can not.

The electron beam irradiation is usually performed in an inert gas, but if necessary, it may be performed in the atmosphere or under conditions in which a small amount of oxygen is introduced.

≪UV curable type, visible light curable type≫
In the method for producing a polarizing film according to the present invention, as the active energy ray, one containing visible light having a wavelength range of 380 nm to 450 nm, particularly an active energy ray having the largest irradiation amount of visible light having a wavelength range of 380 nm to 450 nm is used. Is preferable. As the active energy ray according to the present invention, a gallium-filled metal halide lamp and an LED light source that emits a wavelength range of 380 to 440 nm are preferable. Alternatively, with ultraviolet rays such as low-pressure mercury lamp, medium-pressure mercury lamp, high-pressure mercury lamp, ultra-high pressure mercury lamp, incandescent lamp, xenon lamp, halogen lamp, carbon arc lamp, metal halide lamp, fluorescent lamp, tungsten lamp, gallium lamp, excima laser or sunlight. A light source containing visible light can be used, and a bandpass filter can be used to block ultraviolet rays having a wavelength shorter than 380 nm.

≪Thermosetting type≫
On the other hand, in the thermosetting type forming material, the polarizer and the protective film are bonded together and then heated to initiate polymerization with a thermosetting initiator to form a cured product layer. The heating temperature is set according to the thermal polymerization initiator, but is about 60 to 200 ° C., preferably 80 to 150 ° C.

Further, as the material for forming the transparent resin layer, for example, a cyanoacrylate-based forming material, an epoxy-based forming material, or an isocyanate-based forming material can be used.

Examples of the cyanoacrylate-based forming material include alkyl-α-cyanoacrylate such as methyl-α-cyanoacrylate, ethyl-α-cyanoacrylate, butyl-α-cyanoacrylate, and octyl-α-cyanoacrylate, and cyclohexyl-α-. Examples thereof include cyanoacrylate and methoxy-α-cyanoacrylate. As the cyanoacrylate-based forming material, for example, a material used as a cyanoacrylate-based adhesive can be used.

The epoxy-based forming material may be used as an epoxy resin alone, or may contain an epoxy curing agent. When the epoxy resin is used alone, it is cured by adding a photopolymerization initiator and irradiating it with active energy rays. When an epoxy curing agent is added as the epoxy-based forming material, for example, one used as an epoxy-based adhesive can be used. The epoxy-based forming material can be used as a one-component type containing an epoxy resin and a curing agent thereof, but is also used as a two-component type in which a curing agent is mixed with an epoxy resin. Epoxy-based forming materials are usually used as a solution. The solution may be a solvent-based solution or an aqueous solution such as an emulsion, a colloidal dispersion, or an aqueous solution.

Examples of the epoxy resin include various compounds containing two or more epoxy groups in the molecule. For example, bisphenol type epoxy resin, aliphatic epoxy resin, aromatic epoxy resin, halogenated bisphenol type epoxy resin, biphenyl Examples include based epoxy resins. The epoxy resin can be appropriately determined according to the epoxy equivalent and the number of functional groups, but from the viewpoint of durability, an epoxy resin having an epoxy equivalent of 500 or less is preferably used.

The curing agent for the epoxy resin is not particularly limited, and various types such as a phenol resin type, an acid anhydride type, a carboxylic acid type, and a polyamine type can be used. As the phenol resin-based curing agent, for example, phenol novolac resin, bisphenol novolac resin, xylylene phenol resin, cresol novolac resin and the like are used. Acid anhydride-based curing agents include maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, succinic anhydride and the like, and carboxylic acid-based curing agents include carboxylic acids such as pyromellitic acid and trimellitic acid. Examples thereof include block carboxylic acids to which acids and vinyl ethers are added. Further, as the epoxy-based two-component forming material, for example, a material composed of two liquids of epoxy resin and polythiol, a material composed of two liquids of epoxy resin and polyamide, and the like can be used.

The amount of the curing agent to be blended varies depending on the equivalent amount with the epoxy resin, but is preferably 30 to 70 parts by weight, more preferably 40 to 60 parts by weight, based on 100 parts by weight of the epoxy resin.

Further, as the epoxy-based forming material, various curing accelerators can be used in addition to the epoxy resin and its curing agent. Examples of the curing accelerator include various imidazole compounds and derivatives thereof, dicyandiamide and the like.

Examples of the isocyanate-based forming material include those used as a cross-linking agent in the formation of the pressure-sensitive adhesive layer. As the isocyanate-based cross-linking agent, a compound having at least two isocyanate groups can be used. For example, the polyisocyanate compound can be used as an isocyanate-based forming material. Specifically, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, 1,3-bisisocyanatomethylcyclohexane, hexamethylene diisocyanate, tetramethylxylylene diisocyanate, m-isopropenyl-α, α-Dimethylbenzylisocyanate, methylenebis4-phenylisocyanate, p-phenylenediisocyanate or dimer of these, trimeric such as trisisocyanurate (6-incyanate hexyl), and these biurets, trimethylolpropane, etc. Examples thereof include those reacted with polyhydric alcohol and polyhydric amine. Further, as the isocyanate-based cross-linking agent, those having three or more isocyanate groups such as trisisocyanurate (6-incyanate hexyl) are preferable. Examples of the isocyanate-based forming material include those used as an isocyanate-based adhesive.

Among the isocyanate-based forming materials, in the present invention, it is preferable to use a material having a rigid structure in which a cyclic structure (benzene ring, cyanurate ring, isocyanurate ring, etc.) occupies a large proportion in the structure. As the isocyanate-based forming material, for example, trimethylolpropane-tri-tolyrene isocyanate, tris (hexamethylene diisocyanate) isocyanurate and the like are preferably used.

As the isocyanate-based cross-linking agent, one in which a protecting group is added to a terminal isocyanate group can also be used. Protecting groups include oxime and lactam. When the isocyanate group is protected, the protecting group is dissociated from the isocyanate group by heating, and the isocyanate group reacts.

Further, a reaction catalyst can be used to increase the reactivity of the isocyanate group. The reaction catalyst is not particularly limited, but a tin catalyst or an amine catalyst is preferable. One kind or two or more kinds of reaction catalysts can be used. The amount of the reaction catalyst used is usually 5 parts by weight or less with respect to 100 parts by weight of the isocyanate-based cross-linking agent. When the amount of the reaction catalyst is large, the crosslinking reaction rate becomes high and the forming material foams. Sufficient adhesiveness cannot be obtained even if the foamed forming material is used. Generally, when a reaction catalyst is used, 0.01 to 5 parts by weight, more preferably 0.05 to 4 parts by weight.

As the tin catalyst, either an inorganic catalyst or an organic catalyst can be used, but an organic catalyst is preferable. Examples of the inorganic tin-based catalyst include stannous chloride and stannic chloride. The organic tin-based catalyst preferably has at least one organic group such as an aliphatic group having a skeleton such as a methyl group, an ethyl group, an ether group or an ester group, and an alicyclic group. For example, tetra-n-butyltin, tri-n-butyltin acetate, n-butyltin trichloride, trimethyltin hydroxide, dimethyltin dichloride, dibutyltin dilaurate and the like can be mentioned.

The amine-based catalyst is not particularly limited. For example, those having at least one organic group such as an alicyclic group such as quinoclysine, amidine, and diazabicycloundecene are preferable. Other examples of the amine-based catalyst include triethylamine and the like. Examples of reaction catalysts other than the above include cobalt naphthenate, benzyltrimethylammonium hydroxide and the like.

The isocyanate-based forming material is usually used as a solution. The solution may be a solvent-based solution or an aqueous solution such as an emulsion, a colloidal dispersion, or an aqueous solution. The organic solvent is not particularly limited as long as the components constituting the forming material are uniformly dissolved. Examples of the organic solvent include toluene, methyl ethyl ketone, ethyl acetate and the like. In the case of an aqueous system, for example, alcohols such as n-butyl alcohol and isopropyl alcohol, and ketones such as acetone can be blended. In the case of an aqueous system, a dispersant is used, or a functional group having low reactivity with an isocyanate group such as a carboxylate, a sulfonate, or a quaternary ammonium salt, or an aqueous dispersion of polyethylene glycol or the like is used as an isocyanate-based cross-linking agent. This can be done by introducing a sex component.

The formation of the transparent resin layer by the cyanoacrylate-based forming material, the epoxy-based forming material, or the isocyanate-based forming material can be appropriately selected depending on the type of the forming material, but is usually about 30 to 100 ° C. It is preferably carried out by drying at 50 to 80 ° C. for about 0.5 to 15 minutes. In the case of the cyanoacrylate-based forming material, since the curing is fast, the transparent resin layer can be formed in a time shorter than the above time.

The transparent resin layer may be formed of a forming material that does not contain a curable component, or may be formed of, for example, a forming material that contains the polyvinyl alcohol-based resin as a main component. The polyvinyl alcohol-based resin forming the transparent resin layer may be the same as or different from the polyvinyl alcohol-based resin contained in the polarizer as long as it is a “polyvinyl alcohol-based resin”.

Examples of the polyvinyl alcohol-based resin include polyvinyl alcohol. Polyvinyl alcohol is obtained by saponification of polyvinyl acetate. Examples of the polyvinyl alcohol-based resin include a saponified product of a copolymer of vinyl acetate and a monomer having copolymerizability. When the copolymerizable monomer is ethylene, an ethylene-vinyl alcohol copolymer can be obtained. Examples of the copolymerizable monomer include unsaturated carboxylic acids such as (anhydrous) maleic acid, fumaric acid, crotonic acid, itaconic acid, and (meth) acrylic acid and esters thereof; ethylene, propylene and the like. α-olefin, (meth) allylsulfonic acid (soda), sodium sulfonic acid (monoalkylmalate), sodium disulfonic acid alkylmalate, N-methylolacrylamide, acrylamidealkylsulfonic acid alkali salt, N-vinylpyrrolidone, N- Examples include vinylpyrrolidone derivatives. These polyvinyl alcohol-based resins may be used alone or in combination of two or more. From the viewpoint of controlling the amount of heat of crystal melting of the transparent resin layer to 30 mj / mg or more to satisfy the heat resistance to moisture and water, polyvinyl alcohol obtained by saponifying polyvinyl acetate is preferable.

For example, a polyvinyl alcohol-based resin having a saponification degree of 95% or more can be used, but the amount of heat of crystal melting of the transparent resin layer is controlled to 30 mj / mg or more to satisfy moisture heat resistance and water resistance. From the viewpoint of making the resin, the degree of saponification is preferably 99.0% or more, more preferably 99.7% or more. The degree of saponification represents the ratio of units that are actually saponified to vinyl alcohol units among the units that can be converted to vinyl alcohol units by saponification, and the residue is a vinyl ester unit. The degree of saponification can be determined according to JIS K 6726-1994.

As the average degree of polymerization of the polyvinyl alcohol-based resin, for example, one having a degree of polymerization of 500 or more can be used, but the amount of heat of crystal melting of the transparent resin layer is controlled to 30 mj / mg or more to satisfy moist heat resistance and water resistance. From the viewpoint, the average degree of polymerization is preferably 1000 or more, more preferably 1500 or more, and further preferably 2000 or more. The average degree of polymerization of the polyvinyl alcohol-based resin is measured according to JIS-K6726.

Further, as the polyvinyl alcohol-based resin, a modified polyvinyl alcohol-based resin having a hydrophilic functional group in the side chain of the polyvinyl alcohol or a copolymer thereof can be used. Examples of the hydrophilic functional group include an acetoacetyl group and a carbonyl group. In addition, modified polyvinyl alcohol obtained by acetalizing, urethanizing, etherifying, grafting, or phosphoric acid esterifying a polyvinyl alcohol-based resin can be used.

The forming material containing the polyvinyl alcohol-based resin as a main component may contain a curable component (crosslinking agent) or the like. The ratio of the polyvinyl alcohol-based resin in the transparent resin layer or the forming material (solid content) is preferably 80% by weight or more, more preferably 90% by weight or more, and further preferably 95% by weight or more. However, it is preferable that the forming material does not contain a curable component (crosslinking agent) from the viewpoint that the amount of heat of crystal melting of the transparent resin layer can be easily controlled to 30 mj / mg or more.

As the cross-linking agent, a compound having at least two functional groups reactive with the polyvinyl alcohol-based resin can be used. For example, alkylenediamines having two alkylene groups and two amino groups such as ethylenediamine, triethylenediamine and hexamethylenediamine; tolylene diisocyanate, hydrogenated tolylene diisocyanate, trimethylolpropane tolylene diisocyanate adduct, triphenylmethane triisocyanate, methylenebis. (Isocyanates such as 4-phenylmethane triisocyanate, isophorone diisocyanate and their ketooxime block products or phenol block products; ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerindi or triglycidyl ether, 1,6-hexane. Epoxys such as diol diglycidyl ether, trimethylpropan triglycidyl ether, diglycidyl aniline, diglycidylamine; monoaldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butylaldehyde; Dialdehydes such as dialdehyde, malein dialdehyde, and phthaldialdehyde; amino-formaldehyde resins such as methylol urea, methylol melamine, alkylated methylol urea, alkylated methylolated melamine, acetguanamine, and condensates of benzoguanamine and formaldehyde; Adipic acid dihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutarate dihydrazide, isophthalic acid dihydrazide, sebacic acid dihydrazide, maleate dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide, etc. Examples thereof include water-soluble dihydrazines such as −dihydrazine, propylene-1,3-dihydrazine, butylene-1,4-dihydrazine. Among these, amino-aldehyde resin and water-soluble dihydrazine are preferable. Amino-aldehyde As the resin, a compound having a methylol group is preferable, and among them, methylol melamine, which is a compound having a methylol group, is particularly preferable.

The curable component (crosslinking agent) can be used from the viewpoint of improving water resistance, and the ratio thereof is 20 parts by weight or less, 10 parts by weight or less, and 5 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol-based resin. It is preferably as follows.

The forming material is prepared as a solution in which the polyvinyl alcohol-based resin is dissolved in a solvent. Examples of the solvent include water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide N-methylpyrrolidone, various glycols, polyhydric alcohols such as alcohols, and amines such as ethylenediamine and diethylenetriamine. These can be used alone or in combination of two or more. Among these, it is preferable to use it as an aqueous solution using water as a solvent. The concentration of the polyvinyl alcohol-based resin in the forming material (for example, an aqueous solution) is not particularly limited, but is 0.1 to 15% by weight, preferably 0.5, in consideration of coatability, standing stability, and the like. It is 10% by weight.

Examples of the additive in the forming material (for example, an aqueous solution) include a plasticizer, a surfactant and the like. Examples of the plasticizer include polyhydric alcohols such as ethylene glycol and glycerin. Examples of the surfactant include nonionic surfactants. Further, a silane coupling agent, a coupling agent such as a titanium coupling agent, various tackifiers, an ultraviolet absorber, an antioxidant, a heat-resistant stabilizer, a stabilizer such as a hydrolysis-resistant stabilizer and the like can be blended.

The transparent resin layer can be formed by applying the forming material to the other side surface of the polarizer (the surface on which the protective film is not laminated) and drying it. The coating operation is not particularly limited, and any suitable method can be adopted. For example, various means such as a roll coating method, a spin coating method, a wire bar coating method, a dip coating method, a die coating method, a curtain coating method, a spray coating method, and a knife coating method (comma coating method, etc.) can be adopted.

The transparent resin layer is preferably formed of an ultraviolet curable acrylic resin, an ultraviolet curable epoxy resin, a urethane resin, or a polyvinyl alcohol resin. The urethane-based resin layer is formed from the isocyanate-based forming material.

<Adhesive layer>
An appropriate pressure-sensitive adhesive can be used for forming the pressure-sensitive adhesive layer, and the type thereof is not particularly limited. As adhesives, rubber adhesives, acrylic adhesives, silicone adhesives, urethane adhesives, vinyl alkyl ether adhesives, polyvinyl alcohol adhesives, polyvinylpyrrolidone adhesives, polyacrylamide adhesives, Examples include cellulose-based adhesives.

Among these adhesives, those having excellent optical transparency, exhibiting appropriate wettability, cohesiveness and adhesiveness, and excellent weather resistance and heat resistance are preferably used. An acrylic pressure-sensitive adhesive is preferably used to exhibit such characteristics.

As a method for forming the pressure-sensitive adhesive layer, for example, the pressure-sensitive adhesive is applied to a separator or the like that has been peeled off, and the polymerization solvent or the like is dried and removed to form the pressure-sensitive adhesive layer. The adhesive is applied to a child (or a protective film in the aspect of FIG. 2 (B)) or a polarizer (or a protective film in the aspect of FIG. 2 (B)) in the aspect of FIG. 2 (A). , It is produced by a method of forming a pressure-sensitive adhesive layer into a polarizer by drying and removing a polymerization solvent or the like. When applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be newly added as appropriate.

A silicone release liner is preferably used as the release-treated separator. In the step of applying the pressure-sensitive adhesive of the present invention on such a liner and drying it to form a pressure-sensitive adhesive layer, as a method of drying the pressure-sensitive adhesive, an appropriate method can be appropriately adopted depending on the purpose. Preferably, a method of overheating and drying the coating film is used. The heating and drying temperature is preferably 40 ° C. to 200 ° C., more preferably 50 ° C. to 180 ° C., and particularly preferably 70 ° C. to 170 ° C. By setting the heating temperature in the above range, a pressure-sensitive adhesive having excellent adhesive properties can be obtained.

As the drying time, an appropriate time can be adopted as appropriate. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and particularly preferably 10 seconds to 5 minutes.

Various methods are used as a method for forming the pressure-sensitive adhesive layer. Specifically, for example, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Examples include the extrusion coating method.

The thickness of the pressure-sensitive adhesive layer is preferably 1 μm or more, more preferably 5 μm or more, from the viewpoint of suppressing peeling. On the other hand, if the thickness of the adhesive is too thick, the polarizing element is greatly bent by the mechanical impact applied after the polarizing film is attached to the liquid crystal cell, and nanoslits are likely to occur. Therefore, the thickness is preferably 40 μm. It is 35 μm or less, more preferably 25 μm or less. Further, from the viewpoint of suppressing the shrinkage of the polarizer due to thermal shock, the thickness of the pressure-sensitive adhesive layer is preferably 35 μm or less.

The pressure-sensitive adhesive layer has a storage elastic modulus of 1.0 × 10 ⁴ Pa or more at 23 ° C. so that the polarizing film with the pressure-sensitive adhesive layer is not loaded on the polarizer side due to convex folds and has crack resistance. This is preferable for ensuring (suppression of the generation of nanoslits). The storage elastic modulus of the pressure-sensitive adhesive layer ^{is preferably 5.0 × 10 4} Pa or more. On the other hand, when the storage modulus of the pressure-sensitive adhesive layer is increased, too hard, because of the re-workability is deteriorated, it is preferred storage modulus of the pressure-sensitive adhesive layer is less than 1 × 10 8 ^Pa Further, it is preferably 1 × 10 ⁷ PaPa or less.

When the pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected by a sheet (separator) that has been peeled off until it is put into practical use.

Examples of the constituent material of the separator include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester film, porous materials such as paper, cloth, and non-woven fabric, nets, foam sheets, metal foils, and laminates thereof. A thin leaf body or the like can be mentioned, but a plastic film is preferably used because of its excellent surface smoothness.

The plastic film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer, and for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, and vinyl chloride are all used. Examples thereof include polymer films, polyethylene terephthalate films, polybutylene terephthalate films, polyurethane films, and ethylene-vinyl acetate copolymer films.

The thickness of the separator is usually about 5 to 200 μm, preferably about 5 to 100 μm. If necessary, the separator may be used for mold release and antifouling treatment with a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based mold release agent, silica powder, etc., as well as a coating type, a kneading type, and a vapor deposition type. It is also possible to perform antistatic treatment such as. In particular, the peelability from the pressure-sensitive adhesive layer can be further enhanced by appropriately performing a peeling treatment such as a silicone treatment, a long-chain alkyl treatment, or a fluorine treatment on the surface of the separator.

<Surface protection film>
A surface protective film can be provided on the single protective polarizing film and the polarizing film with an adhesive layer. The surface protective film usually has a base film and an adhesive layer, and protects the polarizer through the adhesive layer.

As the base film of the surface protective film, a film material having or isotropic is selected from the viewpoint of inspectability and controllability. Examples of the film material include polyester resins such as polyethylene terephthalate films, cellulose resins, acetate resins, polyether sulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, and acrylic resins. Examples include transparent polymers such as resins. Among these, polyester resin is preferable. The base film can be used as a laminate of one or more film materials, or a stretched product of the film can also be used. The thickness of the base film is generally 500 μm or less, preferably 10 to 200 μm.

As the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer of the surface protective film, a pressure-sensitive adhesive using a polymer such as (meth) acrylic polymer, silicone-based polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer as a base polymer. Can be appropriately selected and used. From the viewpoint of transparency, weather resistance, heat resistance and the like, an acrylic pressure-sensitive adhesive using an acrylic polymer as a base polymer is preferable. The thickness of the pressure-sensitive adhesive layer (dry film thickness) is determined according to the required adhesive strength. It is usually about 1 to 100 μm, preferably 5 to 50 μm.

The surface protective film may be provided with a peeling treatment layer on the opposite surface of the base film to which the pressure-sensitive adhesive layer is provided, using a low-adhesive material such as a silicone treatment, a long-chain alkyl treatment, or a fluorine treatment. ..

<Other optical layers>
The single-protective polarizing film and the polarizing film with an adhesive layer of the present invention can be used as an optical film laminated with another optical layer in practical use. The optical layer is not particularly limited, but is used for forming, for example, a reflector, a transflective plate, a retardation plate (including a wave plate such as 1/2 or 1/4), a liquid crystal display device such as a viewing angle compensation film, and the like. One or two or more optical layers that may be used can be used. In particular, a reflective polarizing film or a semi-transmissive polarizing film in which a reflecting plate or a semi-transmissive reflecting plate is further laminated on the single-protective polarizing film of the present invention, an elliptically polarizing film in which a retardation plate is further laminated on a polarizing film, or A circularly polarizing film, a wide viewing angle polarizing film in which a viewing angle compensating film is further laminated on the polarizing film, or a polarizing film in which a brightness improving film is further laminated on the polarizing film is preferable.

The optical film in which the optical layer is laminated on the one-sided protective polarizing film or the polarizing film with the adhesive layer can also be formed by a method of sequentially and separately laminating in the manufacturing process of a liquid crystal display or the like, but it is laminated in advance. The optical film has the advantages of excellent quality stability and assembly work, and can improve the manufacturing process of a liquid crystal display or the like. An appropriate adhesive means such as an adhesive layer may be used for laminating. When adhering the above-mentioned polarizing film with an adhesive layer or other optical film, their optical axes can be arranged at an appropriate angle according to a target phase difference characteristic or the like.

The single-protective polarizing film, the polarizing film with an adhesive layer, or the optical film of the present invention can be preferably used for forming various image display devices such as a liquid crystal display device and an organic EL display device. The liquid crystal display device can be formed according to the conventional method. That is, the liquid crystal display device is generally formed by appropriately assembling a liquid crystal cell, a polarizing film or an optical film with an adhesive layer, and if necessary, components such as a lighting system, and incorporating a drive circuit. The present invention is not particularly limited except that a single-protective polarizing film, a polarizing film with an adhesive layer, or an optical film according to the present invention is used, and the same can be applied to the conventional ones. As the liquid crystal cell, any type such as IPS type and VA type can be used, but the IPS type is particularly suitable.

Form an appropriate liquid crystal display device such as a liquid crystal display device in which a single protective polarizing film, a polarizing film with an adhesive layer or an optical film is arranged on one side or both sides of a liquid crystal cell, or a lighting system using a backlight or a reflector. can do. In that case, the polarizing film or optical film with an adhesive layer according to the present invention can be installed on one side or both sides of the liquid crystal cell. When a single protective polarizing film, a polarizing film with an adhesive layer, or an optical film is provided on both sides, they may be the same or different. Further, when forming the liquid crystal display device, for example, an appropriate component such as a diffuser plate, an anti-glare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffuser plate, and a backlight is placed in one layer or at an appropriate position. Two or more layers can be arranged.

<Continuous manufacturing method of image display device>
In the image display device, the polarizing film with the pressure-sensitive adhesive layer unwound from the winding body (roll) of the polarizing film with the pressure-sensitive adhesive layer of the present invention and conveyed by the separator is imaged through the pressure-sensitive adhesive layer. It is preferably manufactured by a continuous manufacturing method (roll-to-panel method) including a step of continuously adhering to the surface of the display panel. Since the polarizing film with an adhesive layer of the present invention is a very thin film, it is cut into a sheet (sheet-fed cutting) and then attached to the image display panel one by one (also referred to as "sheet-to-panel method"). According to the above, it is difficult to handle the sheet when it is transported or attached to the display panel, and the polarizing film (sheet) with an adhesive layer receives a large mechanical impact (for example, bending due to adsorption) in the process. The risk is high. In order to reduce such a risk, it is necessary to take additional measures such as using a thick surface protective film having a base film thickness of 50 μm or more. On the other hand, according to the roll-to-panel method, the polarizing film with an adhesive layer is not cut into a sheet (single-wafer cutting), but is stably conveyed from the roll to the image display panel by a continuous separator. Since it is attached to the image display panel as it is, the above risk can be significantly reduced without using a thick surface protective film. As a result, the transparent resin layer can alleviate the mechanical impact, and the image display panel in which the generation of nanoslits is effectively suppressed can be continuously produced at high speed.

FIG. 8 is a schematic view showing an example of a continuous manufacturing system for a liquid crystal display device adopting a roll-to-panel system.
As shown in FIG. 8, the continuous manufacturing system 100 of the liquid crystal display device has a series of transport units X for transporting the liquid crystal display panel P, a first polarizing film supply unit 101a, a first bonding portion 201a, and a second polarizing film supply. A portion 101b and a second bonding portion 201b are included.
The wound body (first roll) 20a of the polarizing film with the first pressure-sensitive adhesive layer and the wound body (second roll) 20b of the polarizing film with the second pressure-sensitive adhesive layer have an absorption axis in the longitudinal direction. , And the embodiment shown in FIG. 2 (A) is used.

(Transport section)
The transport unit X transports the liquid crystal display panel P. The transport unit X includes a plurality of transport rollers, a suction plate, and the like. The transport unit X is arranged between the first bonding portion 201a and the second bonding portion 201b so that the arrangement relationship between the long side and the short side of the liquid crystal display panel P is exchanged with respect to the transport direction of the liquid crystal display panel P. A replacement unit (for example, rotating the liquid crystal display panel P 90 ° horizontally) 300 is included. As a result, the polarizing film 21a with the first pressure-sensitive adhesive layer and the polarizing film 21b with the second pressure-sensitive adhesive layer can be attached to the liquid crystal display panel P in a cross-nicol relationship.

(1st polarizing film supply unit)
The first polarizing film supply unit 101a continuously supplies the first polarizing film with an adhesive layer (with a surface protective film) 21a unwound from the first roll 20a and conveyed by the separator 5a to the first bonding unit 201a. do. The first polarizing film supply section 101a includes a first feeding section 151a, a first cutting section 152a, a first peeling section 153a, a first winding section 154a, a plurality of transport roller sections, an accumulating section such as a dancer roll, and the like. Have.

The first feeding portion 151a has a feeding shaft on which the first roll 20a is installed, and feeds out a strip-shaped polarizing film with an adhesive layer 21a provided with a separator 5a from the first roll 20a.

The first cutting portion 152a has cutting means such as a cutter and a laser device, and suction means. The first cutting portion 152a cuts the strip-shaped polarizing film 21a with the first pressure-sensitive adhesive layer in the width direction with a predetermined length while leaving the separator 5a. However, as the first roll 20a, a band-shaped polarizing film with an adhesive layer 21a in which a plurality of cut lines are formed in a predetermined length in the width direction is laminated on a separator 5a (an optical film roll with a notch). ) Is not required (the same applies to the second cutting portion 152b described later).

The first peeling portion 153a peels the polarizing film 21a with the first pressure-sensitive adhesive layer from the separator 5a by folding back with the separator 5a inside. Examples of the first peeling portion 153a include a wedge-shaped member and a roller.

The first winding unit 154a winds the separator 5a from which the polarizing film 21a with the first pressure-sensitive adhesive layer has been peeled off. The first winding unit 154a has a winding shaft on which a roll for winding the separator 5a is installed.

(1st bonding part)
The first bonding portion 201a is a polarizing film 21a with a first pressure-sensitive adhesive layer peeled off by the first peeling portion 153a on a liquid crystal display panel P transported by the transporting portion X, and a polarizing film 21a with a first pressure-sensitive adhesive layer. It is continuously bonded through the pressure-sensitive adhesive layer of the above (first bonding step). The first bonding portion 81 is configured to have a pair of bonding rollers, and at least one of the bonding rollers is composed of a drive roller.

(Second polarizing film supply unit)
The second polarizing film supply unit 101b continuously supplies the polarizing film with a second adhesive layer (with a surface protective film) 21b unwound from the second roll 20b and conveyed by the separator 5b to the second bonding unit 201b. do. The second polarizing film supply section 101b includes a second feeding section 151b, a second cutting section 152b, a second peeling section 153b, a second winding section 154b, a plurality of transport roller sections, an accumulating section such as a dancer roll, and the like. Have. The second feeding section 151b, the second cutting section 152b, the second peeling section 153b, and the second winding section 154b are the first feeding section 151a, the first cutting section 152a, the first peeling section 153a, and the first winding, respectively. It has the same configuration and function as the take portion 154a.

(2nd bonding part)
The second bonding portion 201b is a polarizing film 21b with a second pressure-sensitive adhesive layer peeled off by the second peeling portion 153b on a liquid crystal display panel P transported by the transporting unit X, and a polarizing film 21b with a second pressure-sensitive adhesive layer. It is continuously bonded through the pressure-sensitive adhesive layer of the above (second bonding step). The second bonding portion 201b is configured to have a pair of bonding rollers, and at least one of the bonding rollers is composed of a drive roller.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the examples shown below. In addition, each part and% in each example is based on weight. All the conditions for leaving at room temperature, which are not specified below, are 23 ° C. and 65% RH.

<Making a polarizer>
(Preparation of polarizer A0)
Amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) having a water absorption rate of 0.75% and a Tg of 75 ° C. Alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (degree of polymerization 1200, degree of acetoacetyl modification 4.6%, degree of saponification 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd. , Trade name "Gosefimer Z200") at a ratio of 9: 1 was applied and dried at 25 ° C. to form a PVA-based resin layer having a thickness of 11 μm to prepare a laminate.
The obtained laminate was uniaxially stretched at the free end in the longitudinal direction (longitudinal direction) 2.0 times between rolls having different peripheral speeds in an oven at 120 ° C. (aerial auxiliary stretching treatment).
Next, the laminate was immersed in an insolubilizing bath at a liquid temperature of 30 ° C. (an aqueous boric acid solution obtained by blending 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilization treatment).
Next, the polarizing plate was immersed in a dyeing bath having a liquid temperature of 30 ° C. while adjusting the iodine concentration and the immersion time so that the polarizing plate had a predetermined transmittance. In this example, 0.2 parts by weight of iodine was mixed with 100 parts by weight of water, and 1.0 part by weight of potassium iodide was mixed and immersed in the obtained iodine aqueous solution for 60 seconds (dyeing treatment). ..
Next, it was immersed in a cross-linked bath at a liquid temperature of 30 ° C. (an aqueous boric acid solution obtained by blending 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with respect to 100 parts by weight of water) for 30 seconds. (Crossing treatment).
Then, the laminate is immersed in an aqueous solution of boric acid having a liquid temperature of 70 ° C. (an aqueous solution obtained by blending 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with respect to 100 parts by weight of water). However, uniaxial stretching was performed between rolls having different peripheral speeds so that the total stretching ratio was 5.5 times in the longitudinal direction (longitudinal direction) (underwater stretching treatment).
Then, the laminate was immersed in a washing bath at a liquid temperature of 30 ° C. (an aqueous solution obtained by blending 4 parts by weight of potassium iodide with 100 parts by weight of water) (cleaning treatment).
From the above, an optical film laminate containing a polarizer having a thickness of 5 μm was obtained.

(Preparation of polarizers A0 to A3)
In the above-mentioned production of the polarizer A0, the polarizers A1 to A3 were produced in the same manner as in the production of the polarizer A0 except that the production conditions were changed as shown in Table 1. Table 1 shows the thickness, optical characteristics (single transmittance, degree of polarization), and boric acid concentration of the polarizers A1 to A3.

(Preparation of Polarizer B (Polarizer with a thickness of 12 μm))
A polyvinyl alcohol film having an average degree of polymerization of 2400 and a saponification degree of 99.9 mol% and a thickness of 30 μm was immersed in warm water at 30 ° C. for 60 seconds to swell. Then, the film was dyed by immersing it in an aqueous solution having a concentration of iodine / potassium iodide (weight ratio = 0.5 / 8) at a concentration of 0.3% and stretching it up to 3.5 times. Then, stretching was carried out in a boric acid ester aqueous solution at 65 ° C. so that the total stretching ratio was 6 times. After stretching, it was dried in an oven at 40 ° C. for 3 minutes to obtain a PVA-based polarizer. The thickness of the obtained polarizer was 12 μm.

(Preparation of Polarizer C)
Amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 130 μm) having a water absorption rate of 0.75% and a Tg of 75 ° C. Corona treatment is applied to one side of the base material, and polyvinyl is applied to this corona treated surface. Alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (degree of polymerization 1200, degree of acetoacetyl modification 4.6%, degree of saponification 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd. , Trade name "Gosefimer Z200") at a ratio of 9: 1 was applied and dried at 25 ° C. to form a PVA-based resin layer having a thickness of 11 μm to prepare a laminate.
The obtained laminate is shrunk by 30% in the first direction (MD) at 110 ° C. using a simultaneous biaxial stretching machine, and at the same time, stretched 5.0 times in the air in the second direction (TD). (Stretching treatment).
Next, the laminate was immersed in an aqueous iodine solution at 25 ° C. (iodine concentration: 0.2% by weight, potassium iodide concentration: 1.4% by weight) for 40 seconds (dyeing treatment).
The dyed laminate was immersed in a boric acid aqueous solution (boric acid concentration: 5% by weight, potassium iodide concentration: 5% by weight) at 60 ° C. for 80 seconds (crosslinking treatment).
After the cross-linking treatment, the laminate was immersed in a potassium iodide aqueous solution (potassium iodide concentration: 5% by weight) at 25 ° C. for 20 seconds (washing treatment).
From the above, an optical film laminate containing a polarizer having a thickness of 3 μm was obtained.

<Protective film>
Acrylic film 1: A (meth) acrylic resin film having a lactone ring structure having a thickness of 40 μm was used after being subjected to corona treatment on the easily adhesive-treated surface.

Acrylic film 2: A (meth) acrylic resin film having a lactone ring structure having a thickness of 60 μm was used after being subjected to corona treatment on the easily adhesive-treated surface.

Acrylic film 3: A (meth) acrylic resin film having a lactone ring structure having a thickness of 20 μm was used after being subjected to corona treatment on the easily adhesive-treated surface.

TAC1: A triacetyl cellulose film having a thickness of 60 μm was used.

TAC2: A triacetyl cellulose film having a thickness of 40 μm was used.

<Preparation of adhesive to be applied to protective film>
(Acrylic adhesive 1)
It is the same as the composition of the acrylic-based forming material (acrylic 1) of the forming material of the transparent resin layer.

(Acrylic adhesive 2)
N-Hydroxyethyl acrylamide (manufactured by Kojinsha, trade name "HEAA") 12.5 parts Acryloylmorpholin (manufactured by Kojinsha, trade name "ACMO (registered trademark)") 25 parts Dimethylol-tricyclodecandyacrylate (Kyoeisha) Chemical company, trade name "light acrylate DCP-A") 62.5 parts Photoradical polymerization initiator (2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one, manufactured by BASF , Product name "IRGACURE 907") 2 parts Photosensitizer (diethylthioxanthone, manufactured by Nippon Kayakusha, product name "KAYACURE DETX-S") 2 parts

(Acrylic adhesive 3)
N-Hydroxyethyl acrylamide (manufactured by Kojin Co., Ltd., trade name "HEAA") 12.5 parts 2-Hydroxy-3-phenoxypropyl acrylate (manufactured by Toa Synthetic Co., Ltd., trade name "Aronix (registered trademark) M-5700" 25 parts 1,9-Nonandiol diacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Light Acrylate 1.9ND-A") 40 parts Dimethylol-tricyclodecanediacrylate (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Light Acrylate DCP-A" ) 22.5 parts Photoradical polymerization initiator (2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one, manufactured by BASF, trade name "IRGACURE907") 3 parts photosensitizer (Diethylthioxanthone, manufactured by Nippon Kayakusha, trade name "KAYACURE DETX-S") 2 copies

(Epoxy adhesive 3)
The composition of the epoxy-based forming material of the transparent resin layer forming material is the same as that of the epoxy-based forming material (epoxy 1).

(PVA adhesive)
50 parts of methylol melamine at 30 ° C. with respect to 100 parts of a polyvinyl alcohol-based resin containing an acetoacetyl group (average degree of polymerization: 1200, saponification degree: 98.5 mol%, acetoacetylation degree: 5 mol%). An aqueous solution was prepared by dissolving it in pure water under temperature conditions and adjusting the solid content concentration to 3.7%. An alumina colloidal aqueous solution (average particle size 15 nm, solid content concentration 10%, positive charge) was added to 100 parts of the aqueous solution to prepare a PVA adhesive.

<Forming material for transparent resin layer>
(Polyvinyl alcohol-based forming material: PVA1)
A polyvinyl alcohol resin having a degree of polymerization of 2500 and a degree of saponification of 99.7 mol% was dissolved in pure water to prepare an aqueous solution having a solid content concentration of 4% by weight.

(Composition of acrylic forming material: Acrylic 1)
N-Hydroxyethyl acrylamide (manufactured by Kojin Co., Ltd., trade name "HEAA") 20 parts Urethane acrylate (manufactured by Nippon Synthetic Chemical Co., Ltd., trade name "UV-1700B") 80 parts Photoradical polymerization initiator (2-methyl-1- (4-Methylthiophenyl) -2-morpholinopropan-1-one, manufactured by BASF, trade name "IRGACURE907") Part 3 photosensitizer (diethylthioxanthone, manufactured by Nippon Kayakusha, trade name "KAYACURE DETX-S" ”) Part 2

(Composition of epoxy-based forming material: Epoxy 1)
3', 4'-Epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (manufactured by Daicel Chemical Industries, Ltd., trade name "Ceroxide 2021P") 100 parts Photocationic polymerization initiator (4- (phenylthio) phenyldiphenylsulfonium hexafluorophosphate , Made by Sun Appro, product name "CPI-100P") 1 copy

(Preparation of active energy ray-curable forming material)
Among the adhesive and transparent resin forming materials, acrylic and epoxy materials were mixed and stirred at 50 ° C. for 1 hour to prepare various active energy ray-curable forming materials.

<Formation of adhesive layer>
(Acrylic adhesive 1)
≪Preparation of acrylic polymer≫
A four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler was charged with a monomer mixture containing 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate. Further, 0.1 part of 2,2'-azobisisobutyronitrile was charged together with ethyl acetate as a polymerization initiator with respect to 100 parts of the monomer mixture (solid content), and nitrogen gas was introduced while gently stirring. After substituting with nitrogen, the liquid temperature in the flask was maintained at around 60 ° C. and the polymerization reaction was carried out for 7 hours. Then, ethyl acetate was added to the obtained reaction solution to prepare a solution of an acrylic polymer having a weight average molecular weight of 1.4 million adjusted to a solid content concentration of 30%.

≪Preparation of adhesive composition≫
0.2 parts of ethylmethylpyrrolidinium-bis (trifluoromethanesulfonyl) imide (manufactured by Tokyo Kasei Kogyo) and lithium bis (trifluoromethanesulfonyl) imide (Mitsubishi Materials Electronics) with respect to 100 parts of the solid content of the acrylic polymer solution. (Manufactured by Kasei Co., Ltd.) 1 part is blended, and further, 0.1 part of trimethylpropanoxylylene diisocyanate (manufactured by Mitsui Chemicals Co., Ltd .: Takenate D110N), 0.3 part of dibenzoyl sulfide, and γ-glycidoxypropylmethoxy 0.075 parts of silane (manufactured by Shin-Etsu Chemical Industry Co., Ltd .: KBM-403) was blended to prepare an acrylic pressure-sensitive adhesive solution.

(Acrylic adhesive 2)
In the preparation of the acrylic polymer of the above-mentioned acrylic pressure-sensitive adhesive 1, a monomer mixture containing 65 parts of butyl acrylate, 34 parts of methyl methacrylate and 1 part of 4-hydroxybutyl acrylate was used, and instead of ethyl acetate as a solvent. A solution of an acrylic polymer having a weight average molecular weight of 1.1 million was prepared using toluene. Further, in the preparation of the pressure-sensitive adhesive composition, a cross-linking agent (Nippon Polyurethane Industry Co., Ltd.) containing a compound having an isocyanate group instead of 0.1 part of trimethylolpropane xylylene diisocyanate (manufactured by Mitsui Chemicals Co., Ltd .: Takenate D110N) as a main component. An acrylic pressure-sensitive adhesive solution was prepared in the same manner as the acrylic pressure-sensitive adhesive 1 except that one part was used.

(Acrylic adhesive 3)
In the preparation of the acrylic polymer of the above-mentioned acrylic pressure-sensitive adhesive 1, a monomer mixture containing 95 parts of butyl acrylate, 4 parts of acrylic acid and 1 part of 4-hydroxybutyl acrylate was used, and instead of ethyl acetate as a solvent. A solution of an acrylic polymer having a weight average molecular weight of 2.2 million was prepared using toluene. Further, in the preparation of the pressure-sensitive adhesive composition, a cross-linking agent (Nippon Polyurethane Industry Co., Ltd.) containing a compound having an isocyanate group instead of 0.1 part of trimethylolpropane xylylene diisocyanate (manufactured by Mitsui Chemicals Co., Ltd .: Takenate D110N) as a main component. An acrylic pressure-sensitive adhesive solution was prepared in the same manner as the acrylic pressure-sensitive adhesive 1 except that 0.6 part was used.

Examples 1-28, Comparative Examples 1-5
(Making a single protective polarizing film)
A single protective polarizing film was prepared using the polarizer, adhesive, and protective film shown in Table 1. Table 2 shows the optical characteristics (single transmittance, degree of polarization) of the obtained single-protection polarizing film. Although two protective films were used in Example 9, the adhesive layer shown in Table 1 was also used for laminating the two protective films.

In the above, when the polarizers A0 to A3 and C are used, a protective film is attached to the surface of the polarizer of the optical film laminate via an adhesive layer having a thickness shown in Table 1. Next, the amorphous PET substrate was peeled off to prepare a single-protective polarizing film using a thin polarizing element. When the polarizer B is used, a protective film is attached to one side of the PVA-based polarizer via the thick adhesive layer shown in Table 1.

Further, in the above, when the adhesives are acrylic adhesives 1 to 3 and epoxy adhesive 1 (in the case of an ultraviolet curable adhesive), the thickness of the adhesive layer after curing is shown in Table 1. After applying the protective film to the surface of the polarizer while applying the adhesive, the adhesive was cured by irradiating it with ultraviolet rays as active energy rays. Ultraviolet irradiation is a gallium-filled metal halide lamp, irradiation device: Fusion UV Systems, Light Hammer10 manufactured by Inc., valve: V valve, peak illuminance: 1600 mW / cm ² , cumulative irradiation amount 1000 / mJ / cm ² (wavelength 380 to 440 nm). ), And the illuminance of ultraviolet rays was measured using a Solar-Check system manufactured by Solartell. When the adhesive is a PVA-based adhesive, the protective film is attached while being applied to the surface of the polarizer so that the adhesive has the thickness of the adhesive layer after drying shown in Table 1. Then, it was dried at 60 ° C. for 1 minute.

<Making a single protective polarizing film with a transparent resin layer>
A transparent resin layer forming material shown in Table 2 was used on the polarizing element surface of the one-side protective polarizing film (polarizer surface on which the transparent protective film was not provided) so as to have the thickness shown in Table 2. A one-sided protective polarizing film with a transparent resin layer was produced.

In the above, when the forming material of acrylic 1 and epoxy 1 is used as the forming material of the transparent resin layer, the surface of the polarizer is coated with a wire bar coater, and then the active energy rays are irradiated in a nitrogen atmosphere. By doing so, a transparent resin layer was formed. The irradiation of the active energy rays was carried out in the same manner as that used in the production of the single protective polarizing film.

When PVA1 is used as the forming material for the transparent resin layer in the above, the forming material adjusted to 25 ° C. is applied with a wire bar so that the thickness after drying is as shown in Table 2, and then 60 ° C. The film was dried with hot air for 1 minute to prepare a single-protective polarizing film with a transparent resin layer.

<Preparation of polarizing film with adhesive layer>
The solution of the above-mentioned acrylic pressure-sensitive adhesives 1 to 3 was applied to the surface of a polyethylene terephthalate film (separator film) treated with a silicone-based release agent so that the thickness after drying was 5 μm, 15 μm, 20 μm, or 40 μm. It was uniformly coated with a fountain coater and dried in an air circulation type constant temperature oven at 155 ° C. for 2 minutes to form an adhesive layer on the surface of the separator film.

Next, the pressure-sensitive adhesive layer formed on the release-treated surface of the release sheet (separator) was bonded to the transparent resin layer formed on the one-side protective polarizing film so as to have the type and thickness shown in Table 2. A polarizing film with an adhesive layer was produced.

The following evaluations were performed on the polarizing films with an adhesive layer obtained in the above Examples and Comparative Examples. The results are shown in Table 2.

<Elemental transmittance T and degree of polarization P of the polarizer>
The single-unit transmittance T and the degree of polarization P of the obtained single-protection polarizing film were measured using a spectral transmittance measuring device with an integrating sphere (Dot-3c of Murakami Color Technology Laboratory).
The degree of polarization P is the transmittance (parallel transmittance: Tp) when two identical polarizing films are overlapped so that their transmission axes are parallel to each other, and the two transmission axes are overlapped so as to be orthogonal to each other. It is obtained by applying the combined transmittance (orthogonal transmittance: Tc) to the following equation. Polarization degree P (%) = {(Tp-Tc) / (Tp + Tc)} ^1/2 × 100
Each transmittance is shown by a Y value whose visibility is corrected by a 2 degree field of view (C light source) of JIS Z8701 with 100% of completely polarized light obtained through a Granteller prism polarizer.

<Measurement of boric acid content in polarizer>
For the polarizers obtained in Examples and Comparative Examples, total reflection attenuation spectroscopy using polarized light as the measurement light using a Fourier transform infrared spectrophotometer (FTIR) (manufactured by Perkin Elmer, trade name "SPECTRUM2000"). The intensity of the boric acid peak (665 cm ^-1 ) and the intensity of the reference peak (2941 cm ^-1 ) were measured by ATR) measurement. The boric acid content index was calculated from the obtained boric acid peak intensity and the reference peak intensity by the following formula, and the boric acid content (% by weight) was further determined from the calculated boric acid content index by the following formula.
(Boric acid amount index) = (Intensity of boric acid peak 665 cm ^-1 ) / (Intensity of reference peak 2941 cm ^-1 )
(Boric acid content (% by weight)) = (Boric acid content index) x 5.54 + 4.1

<Measurement of compressive elastic modulus at 80 ° C>
A TI900 TriboIndenter (manufactured by Hybrid) was used for measuring the compressive elastic modulus. The obtained single-sided protective polarizing film 11 with a transparent resin layer was cut into a size of 10 mm × 10 mm, fixed to a support equipped with a TriboIndenter, and the compressive elastic modulus was measured by a nanoindentation method. At that time, the position was adjusted so that the indenter used pushed the vicinity of the center of the transparent resin layer. The measurement conditions are shown below.
Indenter used: Berkovic (triangular pyramid type)
Measurement method: Single push measurement Measurement temperature: 80 ° C
Push-in depth setting: 100 nm

<Measurement of storage elastic modulus>
The storage elastic modulus at 23 ° C. was performed using a viscoelastic spectrometer (trade name: RSA-II) manufactured by Leometric. The measurement conditions were a frequency of 1 Hz, a sample thickness of 2 mm, a crimping load of 100 g, and a measurement value at 23 ° C. in the range of −50 ° C. to 200 ° C. at a heating rate of 5 ° C./min.

<Suppression of nanoslit generation: Guitar pick test>
The obtained polarizing film with an adhesive layer was cut into a size of 50 mm × 150 mm (absorption axis direction is 50 mm) and used as sample 11. Sample 11 was used by adhering a surface protective film 6 produced by the following method to the side of the transparent protective film 2.

(Surface protective film for testing)
A substrate molding material made of low-density polyethylene having a melt flow rate of 2.0 g / 10 min and a density of 0.924 g / cm ³ at 190 ° C. was supplied to an inflation molding machine for coextrusion.
At the same time, with an adhesive molding material composed of a propylene-butene copolymer having a melt flow rate of 10.0 g / 10 min at 230 ° C. and a density of 0.86 g / cm ³ (propylene: butene = 85: 15, tactical structure by mass ratio). Was supplied to an inflation molding machine having a die temperature of 220 ° C. for coextrusion molding.
As a result, a surface protective film composed of a base material layer having a thickness of 33 μm and an adhesive layer having a thickness of 5 μm was produced.

Next, as shown in the conceptual diagram of FIG. 5 (A) and the cross-sectional view of FIG. 5 (B), the release sheet (separator) is peeled off from the sample, and the glass plate 20 is passed through the exposed adhesive layer 4. I pasted it on top. Next, a load of 200 g is applied to the central portion of the sample 11 (surface protective film 6 side) by a guitar pick (manufactured by HISTORY, model number "HP2H (HARD)") to the absorption shaft of the polarizer 1 in the sample 11. A load of 50 reciprocations was repeated at a distance of 100 mm in the orthogonal direction. The load was applied at one place.
Next, after the sample 11 was left in an environment of 80 ° C. for 1 hour, the presence or absence of light leakage cracks in the sample 11 was confirmed according to the following criteria.
⊚: No occurrence.
〇: 1 to 5 pieces.
Δ: 6 to 20 pieces.
X: 21 or more.

FIG. 6 is a microscope on the surface of the polarizing film, which serves as the following index for confirming light leakage cracks (nanoslit a) in the guitar pick test of the single protective polarizing film 10 or the single protective polarizing film 11 with a transparent resin layer. This is an example of a photograph of. In FIG. 6A, no crack of light leakage due to the nanoslit a was confirmed. The state as shown in FIG. 6A corresponds to before heating the guitar pick test of the comparative example and after heating the rock'n'roll test of the example (the nanoslit does not allow light to escape due to the expansion suppressing effect). On the other hand, FIG. 6B shows a case where three cracks of light escape due to the nanoslit a are generated in the absorption axis direction of the polarizer due to heating. The state as shown in FIG. 6B corresponds to after heating in the guitar pick test of the comparative example. In FIG. 6, a sample in which nanoslits were generated was observed with a differential interference microscope. When taking a sample, a sample without nanoslits was set under the sample with nanoslits (transmitted light source side) so as to form a cross Nicol, and observation was performed with transmitted light. ..

<Confirmation of through cracks: heat shock test>
The obtained polarizing film with an adhesive layer was cut into 50 mm × 150 mm (absorption axis direction: 50 mm) and 150 mm × 50 mm (absorption axis direction: 150 mm), and cross Nicol was formed on both sides of 0.5 mm thick non-alkali glass. A sample was created by pasting in the direction. The sample was subjected to a heat shock of -40 to 85 ° C. for 30 minutes each x 300 times, and then taken out to visually inspect whether or not penetration cracks (number) were generated in the polarizing film with the adhesive layer. Confirmed at. This test was performed 5 times. The number of cracks was evaluated according to the following.
⊚: 0 sheets.
〇: 1 sheet.
Δ: 2 sheets.
X: 3 or more.

FIG. 7 is an index for confirming the through crack b of the single protective polarizing film 10 or the single protective polarizing film 11 with the transparent resin layer, and is an example of a microscopic photograph of the surface of the polarizing film. In FIG. 7, a sample in which a through crack was generated was observed with a differential interference microscope.

<Curl amount>
After peeling the separator from the obtained polarizing film with the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer surface was facing upward at 23 ° C. and 55% R.I. H. The curl height (mm) after being left for 30 days under the above conditions was measured and evaluated according to the following criteria.
⊚: 0 to 5 mm.
〇: Over 5 mm to 10 mm.
Δ: Over 10 mm to 30 mm.
X: Over 30 mm.

In addition, as in Comparative Examples 4 and 5, the optical characteristics represented by the single transmittance T and the degree of polarization P are represented by the following formula, P>-(10 ^{0.929T-42.4-1} ) × 100 (however, however). When the conditions of T <42.3) or P ≧ 99.9 (however, T ≧ 42.3) are not satisfied, the problem of the present application (generation of through cracks and nanoslits) does not occur. ..

Example 29
A long-shaped one-sided protective polarizing film was used, the forming material was coated with a microgravure coater, and the above-mentioned release sheet (separator) and the following long-shaped surface protective film were used. It is the same as in Example 1 except that it is used. As a result, a wound body of a piece protective polarizing film with a transparent resin layer (aspect described in FIG. 2A) in which a separator was laminated on the transparent resin layer side and a surface protective film was laminated on the transparent protective film side was produced. The wound body of the piece protective polarizing film with a transparent resin layer corresponds to the short side and the long side of 32-inch non-alkali glass by slit processing that advances cutting by continuously transporting the piece protective polarizing film with a transparent resin layer. I prepared a set with the width to be used.

(Surface protective film for roll-to-panel)
Polyethylene terephthalate film with antistatic treatment layer (trade name: Diafoil T100G38, manufactured by Mitsubishi Plastics, thickness 38 μm) is coated with an acrylic adhesive to a thickness of 15 μm on the surface opposite to the antistatic treatment surface. It was formed to obtain a surface protective film.

Next, using a roll-to-panel continuous manufacturing system as shown in FIG. 8, a piece protection with a transparent resin layer continuously supplied from a set of wound bodies of a piece protection polarizing film with a transparent resin layer. The polarizing film was continuously bonded to both sides of 100 sheets of 32 inch non-alkali glass having a thickness of 0.5 mm so as to have a cross Nicol relationship.

Examples 30, 31
Each is the same as in Example 29, except that a piece protective polarizing film with a transparent resin layer is produced by the same manufacturing method as in Examples 2 and 3.

<Confirmation of occurrence of nanoslit: heating test>
100 sheets of non-alkali glass having a single protective polarizing film with a transparent resin layer bonded on both sides were placed in an oven at 80 ° C. for 24 hours, and then the presence or absence of nanoslits was visually confirmed. In any of Examples 28 to 30, no defect (light leakage) was observed due to the nanoslit.

1 Polarizer 2 Protective film 3 Transparent resin layer 4 Adhesive layer 5, 5a, 5b Separator 6, 6a, 6b Surface protective film 10 Single protective polarizing film 11 Single protective polarizing film (with transparent resin layer)
12 Polarizing film with adhesive layer 20a, 20b Winder (roll) of polarizing film with adhesive layer
21a, 21b Polarizing film with adhesive layer (with surface protective film)
100 Continuous manufacturing system of image display device 101a, 101b Polarizing film supply part 151a, 151b Feeding part 152a, 152b Cutting part 153a, 153b Peeling part 154a, 154b Winding part 201a, 201b Laminating part 300 Arrangement replacement part P Image display panel X Image display panel carrier

Claims (19)

A single-sided protective polarizing film having a protective film on only one side of the polarizer.
A transparent resin layer (excluding a transparent resin layer made of a cured product of a photocurable compound) is provided on the other side of the polarizer.
The polarizer contains a polyvinyl alcohol-based resin, and the optical characteristics represented by the simple substance transmittance T and the degree of polarization P are expressed by the following formula P>-(10 ^{0.929T-42.4-1} ) × 100. (However, T <42.3) or
It is configured to satisfy the condition of P ≧ 99.9 (however, T ≧ 42.3).
And when the thickness of the polarizer is X (μm) and the thickness of the transparent resin layer is Y (μm),
X ≦ 12,
0.8 ≤ Y ≤ 1.5 ,
A single-protective polarizing film characterized in that 0.15 ≦ (Y / X) ≦ 0.5. The single-protective polarizing film according to claim 1, wherein the transparent resin layer has a compressive elastic modulus at 80 ° C. of 0.1 GPa or more. The one-sided protective polarizing film according to claim 1 or 2, wherein the transparent resin layer is formed of a thermosetting type forming material or a polyvinyl alcohol-based resin. The single protective polarizing film according to any one of claims 1 to 3, wherein an adhesive layer is provided between the polarizer and the protective film. The one-sided protective polarizing film according to claim 4, wherein the thickness of the adhesive layer is 0.1 μm or more and 5 μm or less. The single-protective polarizing film according to claim 4 or 5, wherein the adhesive layer has a compressive elastic modulus at 80 ° C. of 0.1 GPa or more and 10 GPa or less. The piece according to any one of claims 4 to 6, wherein the adhesive layer is formed of an ultraviolet curable acrylic resin, an ultraviolet curable epoxy resin, a urethane resin, or a polyvinyl alcohol resin. Protective polarizing film. The one-sided protective polarizing film according to any one of claims 1 to 7, wherein the protective film is one sheet and has a thickness of 10 μm or more and 100 μm or less. The number of the protective films is two, the thickness of each protective film is 10 μm or more, the total thickness of the protective films is 100 μm or less, and an adhesive layer or an adhesive layer is provided between the protective films. The one-sided protective polarizing film according to any one of claims 1 to 7. The single-protective polarizing film according to any one of claims 1 to 9, wherein the polarizing element contains boric acid in an amount of 25% by weight or less based on the total amount of the polarizer. The one-sided protective polarizing film according to any one of claims 1 to 10, and a polarizing film with an adhesive layer, which has an adhesive layer. The polarizing film with an adhesive layer according to claim 11, wherein the pressure-sensitive adhesive layer is provided on the transparent resin layer of the single-sided protective polarizing film. The polarizing film with an adhesive layer according to claim 11, wherein the protective film of the single protective polarizing film is provided with the pressure-sensitive adhesive layer. The polarizing film with an adhesive layer according to any one of claims 11 to 13, wherein the thickness of the pressure-sensitive adhesive layer is 1 μm or more and 40 μm or less. The polarizing film with an adhesive layer according to any one of claims 11 to 14, wherein the pressure-sensitive adhesive layer has a storage elastic modulus of 1.0 × 10 ^{4 Pa or more at 23 ° C.} The polarizing film with an adhesive layer according to any one of claims 11 to 15, wherein a separator is provided on the adhesive layer. The polarizing film with an adhesive layer according to claim 16, wherein the polarizing film is a wound body. An image display device having the one-sided protective polarizing film according to any one of claims 1 to 10 or the polarizing film with an adhesive layer according to any one of claims 11 to 15. The polarizing film with an adhesive layer unwound from the winding body of the polarizing film with an adhesive layer according to claim 17 and conveyed by the separator is continuously applied to the surface of an image display panel via the adhesive layer. A method for continuously manufacturing an image display device including a step of bonding to a polarized light.

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