TWI765012B - Single-sided protective polarizing film with adhesive layer, image display device and continuous manufacturing method thereof - Google Patents

Abstract

The object of the present invention is to provide a single-sided protective polarizing film with an adhesive layer that can suppress defects caused by nano-slits even if a coating layer is not provided between the polarizer and the adhesive layer. The single-sided protective polarizing film with an adhesive layer of the present invention is characterized in that: it has a single-sided protective polarizing film with a protective film only on one side of the polarizer, and directly on the polarizer side of the single-sided protective polarizing film The adhesive layer or the intervening coating layer has an adhesive layer; and the storage elastic modulus of the adhesive layer at -40° C. is 7.0×10 ⁷ Pa or more.

Description

Single-sided protective polarizing film with adhesive layer, image display device and continuous manufacturing method thereof

The present invention relates to a single-side protective polarizing film with an adhesive layer, which has a single-side protective polarizing film and an adhesive layer with a protective film only on one side of the polarizer. The aforementioned single-sided protective polarizing film with the adhesive layer can be used alone or as an optical film laminated thereon to form image display devices such as a liquid crystal display device (LCD) and an organic EL display device.

Background of the Invention

In the liquid crystal display device, it is necessary and indispensable to arrange polarizing films on both sides of the glass substrate forming the surface of the liquid crystal panel due to its image forming method. Polarizing films are generally used for polarizers composed of polyvinyl alcohol-based films and dichroic materials such as iodine, and a protective film is attached to one or both sides through a polyvinyl alcohol-based adhesive or the like.

When attaching the said polarizing film to a liquid crystal cell etc., an adhesive agent is normally used. In addition, the adhesive is pre-installed on one side of the polarizing film in the form of an adhesive layer, because it has the advantages of instantly fixing the polarizing film and fixing the polarizing film without a drying step. That is, when attaching a polarizing film, a single-sided protective polarizing film with an adhesive layer is generally used.

In addition, the polarizing film or the single-sided protective polarizing film with the adhesive layer is subjected to thermal shock (such as the thermal shock test under repeated temperature conditions of -30°C and 80°C). Under the severe environment of the test or the high temperature test at 100°C), there is a problem that the change of the shrinkage stress of the polarizer will easily cause cracks (penetrating cracks) in the direction of the absorption axis of the polarizer as a whole. That is, the single-sided protective polarizing film with the adhesive layer has insufficient durability against thermal shock under the aforementioned severe environment. In particular, from the viewpoint of thinning, the single-side protective polarizing film using the adhesive layer of the single-side protective polarizing film provided with the protective film only on one side of the polarizer has insufficient durability against the thermal shock described above. Furthermore, penetration cracks caused by the thermal shock are likely to occur when the size of the polarizing film is increased.

For example, in order to give high durability in high temperature environment, some literatures propose to use one with a storage elastic modulus of 0.2~10MPa at 23°C and a thickness of 2μm or more and less than 25μm, as the single-sided protection of the adhesive layer. An adhesive layer of a polarizing film (Patent Document 1). In addition, in order to provide good durability under high temperature environment, a document has proposed a polarizer, which is provided with a pressure-sensitive adhesive layer on one side of the polarizer and a transparent resin film on the other side of the polarizer. The protective layer formed and the polarizing plate exhibiting a storage elastic modulus of 0.15 to 1 MPa in a temperature range of 23 to 80° C. is used as the aforementioned pressure-sensitive adhesive layer (Patent Document 2). In addition, in order to suppress the occurrence of the above-mentioned penetrating cracks, there is a document suggesting that the shrinkage force in the direction perpendicular to the absorption axis of the polarizer is controlled to be small and the storage elastic modulus of the adhesive layer at 23°C is 0.20 MPa or more. , as the adhesive layer of the single-sided protective polarizing film with the adhesive layer (Patent Document 3). In addition, the polarizer is also thinned. For example, there is a document that proposes a thin polarizer whose optical properties of single transmittance and degree of polarization are controlled and shows high alignment (Patent Document 4).

However, even if the patent document 1 satisfies the durability, since the thickness of the polarizer is as large as 25 μm, penetration cracks in the polarizer due to shrinkage stress cannot be prevented. Moreover, since Patent Documents 1 to 3 are aimed at improving the durability of the single-sided protective polarizing film of the adhesive layer, many boric acids are used for the polarizer. However, it is known that when the amount of boric acid contained in the polarizer exceeds a specific value, the crosslinking of the boric acid is accelerated during heating and the shrinkage stress of the polarizer is increased, so it is not ideal from the viewpoint of suppressing the occurrence of penetrating cracks. That is, in Patent Documents 1 to 3, although the penetrating cracks can be suppressed to some extent by controlling the storage elastic modulus of the adhesive layer, the occurrence of penetrating cracks cannot be said to be sufficiently suppressed.

In addition, the polarizer is also thinned. When the polarizer used to protect the polarizing film on one side of the adhesive layer is thinned, the shrinkage stress variation of the polarizer is also reduced. Therefore, it is known that the above-mentioned penetration crack can be suppressed by using a thinned polarizer.

However, it is known that in the case of controlling the optical properties and reducing the thickness of the polarizer as described in Patent Document 4 (for example, setting the thickness to 12μm or less), when the single-sided protective polarizing film attached to the adhesive layer is loaded with mechanical shock (including the case where the load of convex bending is applied to the polarizer side), extremely fine particles will be locally generated in the direction of the absorption axis of the polarizer. (hereinafter also referred to as nanoslits). It is also known that the generation of the aforementioned nano-slits is independent of the size of the polarizing film. In addition, it is also known that the aforementioned nano-slits do not occur in the case of using a double-sided protective polarizer film with protective films on both sides of the polarizer. It is also known that when a penetrating crack is formed on the polarizer, the The edge stress is relieved so that penetrating cracks do not grow contiguously, but nanoslits grow contiguously in addition to their own. It is also known that penetrating cracks have ductility extending along the direction of the absorption axis of the polarizer in which the cracks have occurred, while nanoslits do not have the aforementioned ductility. In this way, it can be seen that the aforementioned nano-slit is a new problem that occurs when the polarizer is thinned and the optical properties are controlled within a predetermined range for a single-sided protective polarizing film that has suppressed the occurrence of penetrating cracks. A subject derived from the well-known phenomenon of the aforementioned penetration crack.

In addition, since the aforementioned nano-slit is extremely thin, it cannot be measured in a general environment. Therefore, even if nano-slits are formed on the polarizer, it is difficult to identify defects only by light leakage from the single-sided protective polarizing film attached to the adhesive layer. That is, the single-sided protective polarizing film is usually made into a long film and then inspected for defects by automatic optical inspection, but it is difficult to detect nano-slits as defects in this defect inspection. It is known that the defects caused by the aforementioned nano-slits can be caused by the nano-slits along the width direction when the single-sided protective polarizing film with the adhesive layer is attached to the glass substrate of the image display panel and placed in a heating environment. extended and detected (such as the presence or absence of the aforementioned light leakage).

Therefore, as for the single-sided protective polarizing film using the adhesive layer of the thin polarizer, not only the penetration cracks, but also the defects caused by the nano-slits are expected to be suppressed. In addition, the single-sided protective polarizing film with the adhesive layer is thinner than the polarizing film composed of double-sided protective films with protective films on both sides, so it is easy to bend or break the polarizing film during handling.

In order to suppress the defects caused by the aforementioned nano-slits, some literature proposes a polarizer and an adhesive for a single-sided protective polarizing film with an adhesive layer. A technique of providing a transparent layer (coating layer) between the adhesive layers (Patent Document 5). By providing the transparent layer, the polarizing film becomes less likely to be bent when an external stress is applied to the polarizing film, thereby suppressing the generation of nano-slits.

prior art literature

Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2010-44211

Patent Document 2: Japanese Patent Laid-Open No. 2008-197309

Patent Document 3: Japanese Patent Laid-Open No. 2013-72951

Patent Document 4: Specification of Japanese Patent No. 4751481

Patent Document 5: Specification of Japanese Patent No. 6077618

Summary of Invention

The object of the present invention is to provide a single-sided protective polarizing film with an adhesive layer that can suppress defects caused by nano-slits even if a coating layer is not provided between the polarizer and the adhesive layer.

Moreover, the objective of this invention is to provide the image display apparatus which has the said adhesive layer and the single-sided protective polarizing film, its continuous manufacturing method, and the adhesive agent for single-sided protective polarizing films.

As a result of incisive researches, the inventors of the present invention found that the above-mentioned problems can be solved by using the following single-sided protective polarizing film with an adhesive layer, etc., and further reached the present invention.

That is, the present invention relates to a single-sided protective polarizing film with an adhesive layer, which is characterized in that it has a single-sided protective polarizing film with a protective film only on one side of the polarizer, and a single-sided protective polarizing film on the side of the aforementioned single-sided protective polarizing film. The polarizer side has an adhesive layer directly or has an adhesive layer through a coating layer; and the storage elastic modulus of the adhesive layer at -40°C is 7.0×10 ⁷ Pa or more.

The inventors of the present invention have repeatedly and actively studied the relationship between the physical properties of the adhesive layer provided on the polarizer side of the single-sided protective polarizing film and the number of nano-slits generated, and found that the adhesive layer has a low temperature range. There is a correlation between the storage elastic modulus and the nanoslit generation number. In detail, generally speaking, when the external stress is applied to the adhesive layer at a high speed, the storage elastic modulus of the adhesive layer is higher than that when the external stress is applied at a low speed. Also, the storage elastic modulus of the adhesive layer in the low temperature region is higher than the storage elastic modulus in the high temperature region. In other words, when an external stress is applied to the adhesive layer at a high speed, the storage elastic modulus of the adhesive layer will show the same physical property tendency as the storage elastic modulus of the adhesive layer in the low temperature region (the tendency of the storage elastic modulus to increase). . On the other hand, when manufacturing a liquid crystal panel and using a liquid crystal display device, it is conceivable that most of the external stress is applied to the single-sided protective polarizing film of the adhesive layer at a high speed. When the stress is applied to the single-sided protective polarizing film with the adhesive layer at a low speed, nanoslits are more likely to be generated when the stress is applied at a high speed. Therefore, we considered to study the relationship between the storage elastic modulus of the adhesive layer and the number of nanoslits when the external stress was applied to the adhesive layer at a high speed, but when the external stress was applied to the adhesive layer at a high speed. The storage elastic modulus of the adhesive layer is difficult to measure. Therefore, we studied the storage elastic modulus of the adhesive layer in the low temperature region, which showed the same physical property tendency as the storage elastic modulus of the adhesive layer when the external stress was applied to the adhesive layer at a high speed, and the difference between the external stress and the storage elastic modulus. After the relationship between the number of nano-slits generated when the adhesive layer is applied to the single-sided protective polarizing film of the adhesive layer at high speed, it is found that the storage elastic mode of the adhesive layer in the low temperature region, especially at -40°C There is a clear correlation between the number of nanoslits generated when external stress is applied to the single-sided protective polarizing film with the adhesive layer at high speed. Furthermore, we found that by disposing an adhesive layer with a storage elastic modulus of 7.0×10 ⁷ Pa or more at -40°C on the polarizer side of the single-sided protective polarizing film, even if no coating layer is provided, Effectively suppress the generation of nano-slits. In addition, when a coating layer is already provided between the polarizer and the adhesive layer, the formation of nano-slits can be more effectively suppressed by the additive effect between the adhesive layer and the coating layer.

In the aforementioned single-sided protective polarizing film with the aforementioned adhesive layer, the peak value of the attrition elastic modulus of the aforementioned adhesive layer is preferably above -45°C.

In addition, in the single-sided protective polarizing film with the adhesive layer, the storage elastic modulus of the adhesive layer at 85°C is preferably 5.5×10 ⁴ Pa or more and 1.4×10 ⁵ Pa or less.

Also, in the single-sided protective polarizing film with the adhesive layer, the adhesive layer preferably contains a (meth)acrylic polymer as a base polymer, and the (meth)acrylic polymer contains the following as a single Body unit: 50% by weight or more of alkyl (meth)acrylate (A), the glass transition temperature of the homopolymer of which is lower than 0°C; and 0.1 to 20% by weight of high Tg monomer (B) selected from the group consisting of (meth)acrylic acid alkyl ester (b1) and (meth)acryloyl group-containing monomer (b2) Glass transition temperature of at least one of the homopolymers of the above-mentioned alkyl (meth)acrylate (b1) is 0°C or higher, and the glass of the homopolymers of the above-mentioned (meth)acryloyl group-containing monomer (b2) The transition temperature is 0°C or higher and it has a heterocyclic ring.

In addition, the (meth)acrylic polymer preferably further contains a polar monomer other than the (meth)acryloyl group-containing monomer (b2) as a monomer unit, and the polar monomer is selected from the group consisting of nitrogen-containing monomers. At least one of the group consisting of a monomer, a carboxyl group-containing monomer and a hydroxyl group-containing monomer.

The aforementioned nitrogen-containing monomer is preferably a vinyl-based monomer having a lactamide ring. In addition, the aforementioned vinyl-based monomer having a lactamide ring is preferably a vinylpyrrolidone-based monomer. In addition, the aforementioned vinylpyrrolidone-based monomer is preferably N-vinylpyrrolidone.

In the aforementioned (meth)acrylic polymer, it is preferable to contain 0.1 to 5 wt % of the aforementioned nitrogen-containing monomer as a monomer unit, 0.01 to 3 wt % of the aforementioned carboxyl group-containing monomer, and preferably 0.01 to 1 wt % % of the aforementioned hydroxyl-containing monomers.

In the single-sided protective polarizing film with the adhesive layer, the thickness of the polarizer is preferably 12 μm or less.

Also, in the single-sided protective polarizing film with the adhesive layer, the polarizer preferably contains a polyvinyl alcohol-based resin, and is preferably structured such that the optical properties represented by the monomer transmittance T and the degree of polarization P satisfy the conditions of the following formula : P>-(10 ^0.929T-42.4 -1)×100 (only, T<42.3), or P≧99.9 (only, T≧42.3).

In addition, in the single-sided protective polarizing film with the adhesive layer, the polarizer preferably contains 25% by weight or less of boric acid with respect to the total amount of the polarizer.

In addition, a separator may be provided on the adhesive layer of the single-sided protective polarizing film of the adhesive layer. A single-sided protective polarizing film with a separate adhesive layer can be used as a roll.

Furthermore, the present invention relates to an image display device having a single-sided protective polarizing film with an adhesive layer.

In addition, the present invention relates to a continuous manufacturing method of an image display device, comprising the steps of: releasing the above-mentioned adhesive layer from the roll body of the above-mentioned single-sided protective polarizing film with the above-mentioned adhesive layer and conveyed by the above-mentioned separating member The single-sided protective polarizing film is continuously attached to the surface of the image display panel through the aforementioned adhesive layer.

In addition, the present invention relates to an adhesive, which is characterized in that: it is a material for forming an adhesive layer, and the adhesive layer is provided on the polarizer that only has a protective film on one side of the polarizer to protect the polarizer film on one side. In addition, the aforementioned adhesive contains at least a (meth)acrylic polymer, and the (meth)acrylic polymer contains the following as monomer units: 50% by weight or more of alkyl (meth)acrylate ( A), the glass transition temperature of its homopolymer is lower than 0°C; and 0.1 to 20% by weight of high Tg monomer (B), which is selected from the group consisting of alkyl (meth)acrylate (b1) and containing At least one of the group consisting of the (meth)acryloyl monomer (b2), the glass transition temperature of the homopolymer of the above-mentioned alkyl (meth)acrylate (b1) is 0°C or more, the above-mentioned containing ( The glass transition temperature of the homopolymer of the meth)acryloyl monomer (b2) is 0°C or higher and Has a heterocycle.

In terms of the aforementioned adhesive, the aforementioned (meth)acrylic polymer preferably further contains a polar monomer other than the aforementioned (meth)acryloyl group-containing monomer (b2) as a monomer unit, and the polar monomer system is selected from the group consisting of: At least one of the group consisting of nitrogen-containing monomers, carboxyl-containing monomers and hydroxyl-containing monomers.

The aforementioned nitrogen-containing monomer is preferably a vinyl-based monomer having a lactamide ring. In addition, the aforementioned vinyl-based monomer having a lactamide ring is preferably a vinylpyrrolidone-based monomer. In addition, the aforementioned vinylpyrrolidone-based monomer is preferably N-vinylpyrrolidone.

For the aforementioned adhesive, in the aforementioned (meth)acrylic polymer, it is preferable to contain 0.1 to 5% by weight of the aforementioned nitrogen-containing monomer as a monomer unit, and preferably 0.01 to 3% by weight of the aforementioned carboxyl group-containing monomer, And it is suitable to contain 0.01 to 1% by weight of the aforementioned hydroxyl-containing monomer.

The single-sided protective polarizing film with the adhesive layer of the present invention is provided with an adhesive layer with a storage elastic modulus of 7.0×10 ⁷ Pa or more at -40°C on the polarizer side of the single-sided protective polarizing film, and the aforementioned The adhesive layer has high elastic properties (high storage elastic modulus in low temperature region) when external stress is applied at high speed, so the polarizing film is less likely to bend when the polarizing film is mechanically impacted at high speed. As a result, the generation of nano-slits can be effectively suppressed even if no coating layer is provided. In addition, the single-sided protective polarizing film with the adhesive layer of the present invention can omit the step of disposing the coating layer, so the productivity can be improved more than the conventional one having the coating layer.

1: polarizer

2: Protective film

3: Adhesive layer

4: Adhesive layer

5, 5a, 5b: Separate parts

6, 6a, 6b: Surface protection film

10: Single-sided protective polarizing film

11: One-sided protective polarizing film with adhesive layer

20: glass plate

20a: Rolled body of single-sided protective polarizing film with the first adhesive layer (first roll)

20b: Rolled body of single-sided protective polarizing film with second adhesive layer (second roll)

21a: Single-sided protective polarizing film for the first adhesive layer (with surface protective film)

21b: Single-sided protective polarizing film for the second adhesive layer (with surface protective film)

100: Continuous manufacturing system of image display device (liquid crystal display device)

101a: first polarizing film supply unit

101b: Second polarizing film supply part

151a: Release 1

151b: Release 2

152a: 1st cut

152b: 2nd cut

153a: 1st peeling part

153b: 2nd peeling part

154a: Coiling Section 1

154b: 2nd take-up section

201a: 1st Fitting Section

201b: 2nd Fitting Section

300: Configure replacement part

P: Image display panel

X: The conveying part of the image display panel

a: Nano slit

b: penetrating crack

FIG. 1 is an example of a schematic cross-sectional view of a single-sided protective polarizing film with an adhesive layer of the present invention.

FIG. 2 is an example of a conceptual diagram comparing nano-slits and penetrating cracks generated in a polarizer.

FIG. 3 is a schematic diagram illustrating evaluation items related to nanoslits in Examples and Comparative Examples.

FIG. 4 is an example of a photograph showing cracks generated by nanoslits related to the evaluation of Examples and Comparative Examples.

FIG. 5 is an example of a schematic cross-sectional view of a continuous manufacturing system of an image display device.

Form for carrying out the invention

Referring to FIG. 1 , the single-sided protective polarizing film with the adhesive layer of the present invention will be described below. The single-sided protective polarizing film 11 with the adhesive layer of the present invention has, for example, a single-sided protective polarizing film 10 and an adhesive layer 4 . As shown in FIG. 1 , the single-sided protective polarizing film 10 only has the protective film 2 on one side of the polarizer 1 . The polarizer 1 and the protective film 2 are laminated through an adhesive layer 3 (other intermediary layers such as an adhesive layer, a primer layer, and the like). In addition, although not shown, the single-sided protective polarizing film 10 may be provided with an easily bonding layer on the protective film 2 or an activation treatment may be performed on it, so that the easily bonding layer and the adhesive may be laminated. In addition, although not shown, the protective film 2 can be provided in multiple sheets. A plurality of protective films 2 can be laminated through an adhesive layer 3 (other intermediary layers such as an adhesive layer, a primer layer, etc.).

Also as shown in Figure 1, the single side of the adhesive layer of the present invention The adhesive layer 4 in the protective polarizing film 11 can be disposed on the polarizer 1 side of the single-sided protective polarizing film 10 . In addition, although not shown in the drawing, a coating layer may also be provided between the polarizer 1 and the adhesive layer 4 . The said coating layer is not specifically limited, For example, a well-known transparent layer etc. which are described in the specification of Japanese Patent No. 6077618 can be applied. In addition, a separator 5 can be provided on the adhesive layer 4 of the single-sided protective polarizing film 11 for adhering the adhesive layer of the present invention, and a surface protection film 6 can be provided on the opposite side thereof. The single-sided protective polarizing film 11 with the adhesive layer in FIG. 1 shows the case where both the separator 5 and the surface protective film 6 are provided. The single-sided protective polarizing film 11 with at least the adhesive layer of the separator 5 (and the one with the surface protective film 6 ) can be used as a roll body, for example, it is beneficial to be used in applications that will be released from the roll body and will be described later. The method in which the single-sided protective polarizing film 11 with the adhesive layer conveyed by the separator 5 is pasted on the surface of the image display panel through the adhesive layer 4 (hereinafter also referred to as the "roll to panel method", representing the above There is Japanese Patent No. 4406043 specification). The single-sided protective polarizing film with the adhesive layer described in FIG. 1 is suitable for use from the viewpoints of suppressing warpage of the display panel after lamination, suppressing the occurrence of nano-slits, and the like.

FIG. 2 is a conceptual diagram comparing the nano-slit a and the penetrating crack b formed in the polarizer. FIG. 2(A) shows the nanoslit a formed in the polarizer 1 , and FIG. 2(B) shows the penetrating crack b formed in the polarizer 1 . The nano-slit a is generated by mechanical shock, and the nano-slit a locally generated in the direction of the absorption axis of the polarizer 1 cannot be confirmed at the moment of generation, but can be generated in a thermal environment (such as 80°C or 60°C). , 90%RH) is confirmed by expanding in the width direction. On the other hand, it is generally believed that the nanoslit a does not have a characteristic along the polarizer. The ductility extending in the direction of the absorption axis. In addition, the aforementioned nanoslit a is considered to be generated regardless of the size of the polarizing film. Nanoslits a will generate independently, and will also generate adjacent to each other. On the other hand, the penetration crack b is generated by thermal shock (for example, thermal shock test). The penetrating crack has a ductility extending in the direction of the absorption axis of the polarizer in which the crack has occurred. When the penetrating crack b is generated, the peripheral stress is released, so that the penetrating crack is not formed adjacently.

<Polarizer>

In the present invention, the thickness of the polarizer is preferably 12 μm or less, more preferably 10 μm or less, still more preferably 8 μm or less, and still more preferably 7 μm or less, from the viewpoint of thinning and suppressing the generation of penetrating cracks. is 6 μm or less. On the other hand, the thickness of the polarizer is preferably 1 μm or more. Such a thin polarizer has less thickness variation, good visibility, and less dimensional change, so it is excellent in durability against thermal shock.

As the polarizer, a polyvinyl alcohol-based resin is used. Examples of polarizers include hydrophilic polymer films such as polyvinyl alcohol-based films, partially formalized polyvinyl alcohol-based films, and ethylene-vinyl acetate copolymer-based partially saponified films that adsorb iodine or two of dichroic dyes. Color substances and uniaxially stretched, and polyolefin-based oriented films such as dehydration-treated products of polyvinyl alcohol or dehydrochloric acid-treated products of polyvinyl chloride. Among them, a polarizer composed of a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferable.

For example, a polarizer made of a polyvinyl alcohol-based film dyed with iodine and then uniaxially stretched can be produced in the following way: dipping polyvinyl alcohol into an aqueous solution of iodine to dye it, and then extending to 3 to 7 times its original length. . as needed It may contain boric acid, zinc sulfate, zinc chloride, etc., and may be immersed in an aqueous solution of potassium iodide or the like. Further, the polyvinyl alcohol-based film may be immersed in water and washed with water before dyeing as necessary. By washing the polyvinyl alcohol-based film with water, dirt and anti-caking agents on the surface of the polyvinyl-alcohol-based film can be washed away, and in addition to swelling the polyvinyl-alcohol-based film, uneven dyeing and other unevenness can be prevented. The extension may be carried out after dyeing with iodine, or may be dyed and stretched at the same time, or may be dyed with iodine after extension. The extension can also be carried out in an aqueous solution such as boric acid or potassium iodide or in a water bath.

The polarizer preferably contains boric acid from the viewpoint of extension stability or optical durability. In addition, from the viewpoint of suppressing the occurrence of penetrating cracks and nanoslits and suppressing expansion, the content of boric acid contained in the polarizer is preferably 25 wt % or less, more preferably 20 wt % or less, based on the total amount of the polarizer. It is preferably 18% by weight or less, more preferably 16% by weight or less. When the content of boric acid contained in the polarizer exceeds 25% by weight, even if the thickness of the polarizer has been reduced (for example, the thickness is less than 12 μm), the shrinkage stress of the polarizer will still increase and penetration cracks are likely to occur, which is not ideal. On the other hand, from the viewpoint of the extension stability and optical durability of the polarizer, the boric acid content is preferably 10% by weight or more, more preferably 12% by weight or more, based on the total amount of the polarizer.

Typical examples of thin polarizers include: Japanese Patent No. 4751486, Japanese Patent No. 4751481, Japanese Patent No. 4815544, Japanese Patent No. 5048120, Thin polarizers described in Japanese Patent No. 5587517, International Publication No. 2014/077599 Handbook, International Publication No. 2014/077636 Handbook, etc., or thin polarizers obtained by the production methods described in them.

The aforementioned polarizer is preferably constructed so that the optical properties represented by the single transmittance T and the degree of polarization P satisfy the following formula: P>-(10 ^{0.929T-42.4-1} )×100 (but, T<42.3), Or P≧99.9 (but, T≧42.3). In a word, the polarizer configured to satisfy the aforementioned conditions has the performance required for a liquid crystal television display using a large-scale display element. Specifically, the contrast ratio is 1000:1 or more and the maximum brightness is 500 cd/m ² or more. For other uses, for example, it can be attached to the viewing side of an organic EL display device.

On the other hand, a polarizer that satisfies the above conditions is formed of a polymer (for example, polyvinyl alcohol-based molecules) that exhibits high alignment, so it is compatible with a thin type (for example, a thickness of 12 μm or less), so that the absorption of the polarizer can be reduced. The tensile fracture stress in the direction perpendicular to the axis direction is significantly reduced. As a result, for example, when subjected to a mechanical shock greater than the tensile fracture stress during the manufacturing process of the polarizing film, nanoslits are likely to be formed along the direction of the absorption axis of the polarizer. Therefore, the present invention is particularly suitable for using a single-sided protective polarizing film with the polarizer (or using a single-sided protective polarizing film with an adhesive layer thereon).

In the production method including the step of stretching and the step of dyeing in the state of a laminated body, from the viewpoint of being able to stretch at a high magnification and improving the polarizing performance, the aforementioned thin polarizer is known as Japanese Patent No. 4751486. The description, the description of Japanese Patent No. 4751481, the description of Japanese Patent No. 4815544 described in the preparation method including the step of extending in boric acid aqueous solution is suitable, and especially the description of Japanese Patent No. 4751481, Japanese Patent No. 4815544 The one described in the specification No. is preferably obtained by a production method including the step of auxiliary in-air stretching before stretching in an aqueous solution of boric acid. These thin polarizers can be obtained by a production method comprising the following steps: a step of extending a layer of a polyvinyl alcohol-based resin (hereinafter, also referred to as a PVA-based resin) and a resin substrate for stretching in the state of a laminate; and staining step. In this production method, even if the PVA-based resin layer is thin, it is supported by the resin base material for stretching, and can be stretched without problems such as fracture caused by stretching.

<Protective film>

The material constituting the aforementioned protective film is preferably one that is excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy, and the like. Examples include: polyester-based polymers such as polyethylene terephthalate and polyethylene naphthalate; cellulose-based polymers such as diacetyl cellulose and triacetyl cellulose; polymethyl methacrylate Acrylic polymers such as esters; styrene polymers such as polystyrene and acrylonitrile-styrene copolymer (AS resin); and polycarbonate polymers. In addition, the following polymers can also be cited as examples of the polymers forming the above-mentioned transparent protective film: polyethylene, polypropylene, polyolefins having a ring system or even a norbornene structure, such as polyolefin-based polymerization of ethylene-propylene copolymers polyamides, vinyl chloride-based polymers, amide-based polymers such as nylon and aromatic polyamides, imine-based polymers, polyamide-based polymers, polyether-based polymers, polyetheretherketone-based polymers, polyamide-based polymers Benzene sulfide polymer, vinyl alcohol polymer, chlorine vinylidene-based polymers, vinyl butyral-based polymers, arylate-based polymers, polyoxymethylene-based polymers, epoxy-based polymers, or blends of the above polymers, etc.

In addition, one or more optional and appropriate additives may be contained in the protective film. The additives include, for example, ultraviolet absorbers, antioxidants, slip agents, plasticizers, mold release agents, anticoloring agents, flame retardants, nucleating agents, antistatic agents, pigments, colorants, and the like. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, preferably 50 to 99% by weight, more preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. When content of the said thermoplastic resin in a protective film is 50 weight% or less, there exists a possibility that the high transparency etc. which are originally thermoplastic resin cannot fully be exhibited.

As the protective film, a retardation film, a brightness enhancement film, a diffusion film and the like can also be used. As the retardation film, for example, a retardation film having a front phase difference of 40 nm or more and/or a thickness direction retardation of 80 nm or more can be mentioned. The front phase difference is usually controlled in the range of 40~200nm, and the thickness direction retardation is usually controlled in the range of 80~300nm. When the retardation film is used as a protective film, the retardation film can also function as a polarizer protective film, so that the thickness can be reduced.

The retardation film includes a birefringent film formed by uniaxially or biaxially stretching a thermoplastic resin film. The above-mentioned stretching temperature, stretching ratio, etc. can be appropriately set according to the retardation value, film material, and thickness.

The thickness of the protective film can be appropriately determined, but is generally about 1 to 500 μm from the viewpoints of strength, workability such as handling properties, and thin layer properties. special It should be 1~300μm, preferably 5~200μm, more preferably 5~150μm, and especially the thin type of 5~80μm.

Functional layers such as a hard coat layer, an anti-reflection layer, an anti-adhesion layer, a diffusion layer and an anti-glare layer can be provided on the surface of the aforementioned protective film that is not connected to the polarizer. In addition, the above-mentioned functional layers such as the hard layer, anti-reflection layer, anti-stick layer, diffusion layer and anti-glare layer can be provided not only on the protective film itself, but also separately from the protective film and separately.

<intermediary layer>

The protective film and the polarizer can be laminated through intervening layers such as an adhesive layer, an adhesive layer, and a primer layer. At this time, it is desirable that the two can be laminated without an air gap through an interposer. The protective film and the polarizer are preferably laminated through an adhesive.

The adhesive layer is formed of an adhesive. The type of the adhesive is not particularly limited, and various substances can be used. The above-mentioned adhesive layer is not particularly limited as long as it is optically transparent, and various forms of adhesives such as water-based, solvent-based, hot-melt adhesive, and active energy ray-curable adhesives can be used. Follow-up is appropriate.

As the water-based adhesive, for example, an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based latex-based adhesive, and a water-based polyester can be exemplified. The water-based adhesive is usually used as an adhesive composed of an aqueous solution, and usually contains a solid content of 0.5 to 60% by weight.

Active energy ray curing adhesives are adhesives that are cured by active energy rays such as electron beams, ultraviolet rays (radical curing type, cation curing type), such as electron beam curing type and ultraviolet curing type. The form of transformation is used. As an active energy ray hardening type adhesive agent, for example, a photoradical hardening type adhesive agent can be used. When an active-energy ray-curable adhesive of a photoradical curing type is used as an ultraviolet curing type, the adhesive contains a radically polymerizable compound and a photopolymerization initiator.

The coating method of the adhesive can be appropriately selected according to the viscosity of the adhesive or the target thickness. Examples of the coating method include, for example, a reverse coater, a gravure coater (direct, reverse or indirect), a bar reverse coater, a roll coater, a die coater, a bar coater, a rod coater, etc. . In other respects, methods such as dip coating can be appropriately used for coating.

In addition, when an aqueous adhesive or the like is used for the application of the adhesive, it is preferable to perform the adhesive layer finally formed so that the thickness of the adhesive layer is 30 to 300 nm. The thickness of the aforementioned adhesive layer is more preferably 60-250 nm. Moreover, when using an active energy ray hardening type adhesive agent, it is preferable to carry out so that the thickness of the said adhesive agent layer may become 0.1-200 micrometers. It is preferably 0.5 to 50 μm, and more preferably 0.5 to 10 μm.

In addition, when the polarizer and the protective film are laminated, an easy-adhesion layer may also be provided between the protective film and the adhesive layer. The easily bonding layer can be formed of various resins having, for example, a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a polysiloxane, a polyamide skeleton, and a polyimide skeleton. , polyvinyl alcohol skeleton, etc. These polymer resins may be used alone or in combination of two or more. Moreover, other additives may be added when forming the easily bonding layer. Specifically, stabilizers such as tackifiers, ultraviolet absorbers, antioxidants, and heat-resistant stabilizers can be used.

The easy-bonding layer is usually set on the protective film in advance, by The adhesive layer is laminated with the polarizer on the easily bonding layer side of the protective film. The formation of the easy-bonding layer can be performed by applying a material for forming the easily-bonding layer on the protective film by a known technique and drying. The forming material of the easy-bonding layer is usually adjusted to a solution diluted to an appropriate concentration in consideration of the thickness after drying and the smoothness of coating. The thickness of the easy-bond layer after drying is preferably 0.01-5 μm, preferably 0.02-2 μm, and more preferably 0.05-1 μm. In addition, the easily bonding layer may be provided with multiple layers, and in this case, the total thickness of the easily bonding layer is preferably within the above-mentioned range.

The adhesive layer is formed of an adhesive. As the adhesive, various adhesives can be used, and examples thereof include rubber-based adhesives, acrylic-based adhesives, silicone-based adhesives, urethane-based adhesives, vinyl alkyl ether-based adhesives, and polyvinylpyrrole. Peridone-based adhesives, polyacrylamide-based adhesives, cellulose-based adhesives, etc. The adhesive base polymer can be selected according to the type of the aforementioned adhesive. Among the above-mentioned adhesives, the use of acryl-based adhesives is preferable in terms of good optical transparency, adequate wettability, adhesive properties of cohesion and adhesiveness, and excellent weather resistance and heat resistance.

The primer layer (primer layer) is formed to improve the adhesion between the polarizer and the protective film. The material constituting the undercoat layer is not particularly limited as long as it can exhibit a certain degree of strong adhesion to both the base film and the polyvinyl alcohol-based resin layer. For example, a thermoplastic resin excellent in transparency, thermal stability, elongation, and the like can be used. As the thermoplastic resin, for example, acrylic resin, polyolefin-based resin, polyester-based resin, polyvinyl alcohol-based resin, or a mixture thereof may be mentioned.

<Adhesive layer>

The adhesive layer of the single-sided protective polarizing film with the adhesive layer of the present invention is as described above, and the storage elastic modulus at -40° C. is 7.0×10 ⁷ Pa or more. From the viewpoint of more effectively suppressing the generation of nano-slits, the storage elastic modulus of the adhesive layer at -40°C is preferably 8.0×10 ⁷ Pa or more, more preferably 1.0×10 ⁸ Pa or more. On the other hand, from the viewpoint of preventing peeling that occurs when dropped at a low temperature, the storage elastic modulus of the adhesive layer at -40°C is preferably 1.0×10 ¹⁰ Pa or less.

In addition, from the viewpoint of imparting high elastic properties when external stress is applied at a high speed, making the polarizing film less likely to bend, thereby more effectively suppressing the generation of nano-slits, the peak value of the loss elastic modulus of the adhesive layer is preferably at Above -45°C, preferably above -40°C, and more preferably above -35°C. On the other hand, from the viewpoint of preventing the adhesive layer from being unable to be used as an adhesive layer because the adhesiveness of the adhesive layer is not exhibited, the peak value of the attrition elastic modulus of the adhesive layer is usually 0° C. or lower.

When manufacturing a liquid crystal panel and using a liquid crystal display device, external stress may be applied to the single-sided protective polarizing film of the adhesive layer at a low speed, and the nano-slits generated at this time should also be suppressed. Based on the same viewpoint as the relationship between the storage elastic modulus of the adhesive layer in the low temperature region and the number of nanoslits generated, the inventors of the present invention aimed at the relationship between the storage elastic modulus of the adhesive layer in the high temperature region and the nanoslit generation number. After studying the relationship between the number of slits produced, it was found that the storage elastic modulus of the adhesive layer in the high temperature region, especially at 85 °C, and the external stress were applied to the single-sided protection of the adhesive layer at a low speed. There is a correlation between the number of nanoslits generated in polarizing films. Moreover, we also found that as long as the storage elastic modulus of the adhesive layer at 85°C is 5.5×10 ⁴ Pa or more, the external stress can also be suppressed from being applied to the single-sided protective polarizing film attached to the adhesive layer at a low speed. The nano-slits will be generated. From the viewpoint of further suppressing the aforementioned nano-slits, the storage elastic modulus of the adhesive layer at 85° C. is preferably 6.0×10 ⁴ Pa or more, more preferably 7.0×10 ⁴ Pa or more. On the other hand, if the storage elastic modulus of the adhesive layer at 85°C is too high, the adhesive layer will be easily peeled off from the polarizer when the size of the polarizer that protects the polarizing film on one side changes due to thermal shrinkage. tendency. Therefore, the storage elastic modulus of the adhesive layer at 85° C. is preferably 1.4×10 ⁵ Pa or less, and more preferably 1.3×10 ⁵ Pa or less.

The thickness of the aforementioned adhesive layer is not particularly limited, for example, it may be about 1 to 100 μm, preferably 2 to 50 μm, more preferably 2 to 40 μm, and more preferably 5 to 35 μm.

For the formation of the aforementioned adhesive layer, an appropriate adhesive can be used, and the type thereof is not particularly limited. Examples of the adhesive include rubber-based adhesives, acrylic-based adhesives, polysiloxane-based adhesives, urethane-based adhesives, vinyl alkyl ether-based adhesives, polyvinyl alcohol-based adhesives, and polyvinylpyrrole. Peridone-based adhesives, polyacrylamide-based adhesives, cellulose-based adhesives, etc.

Among these adhesives, those having good optical transparency, exhibiting moderate wettability, cohesiveness and adhesive properties, and excellent weather resistance and heat resistance are also suitably used. For those exhibiting such characteristics, it is preferable to use an acrylic adhesive. Hereinafter, the case where an acrylic pressure-sensitive adhesive is used as the material for forming the pressure-sensitive adhesive layer will be described.

The aforementioned acrylic adhesive can be used with (meth)acrylic acid A (meth)acrylic polymer in which the monomer unit of an alkyl ester is used as a main skeleton is used as a base polymer. In addition, (meth)acrylate means acrylate and/or methacrylate, and (meth) of this invention also has the same meaning.

The alkyl (meth)acrylate constituting the main skeleton of the (meth)acrylic polymer has about 1 to 18 carbon atoms in the alkyl group, and specific examples of the alkyl (meth)acrylate can be exemplified as ( Methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, Amyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, (meth)acrylic acid Nonyl ester, isononyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, octadecyl (meth)acrylate, etc., and these may be used alone or in combination.

In order to obtain an adhesive layer having the peaks of the aforementioned storage elastic modulus and the aforementioned loss elastic modulus, the (meth)acrylic polymer preferably contains the following monomer units: 50% by weight or more (more preferably 60% by weight or more) , more preferably more than 70% by weight, more preferably more than 80% by weight) of alkyl (meth)acrylate (A), the glass transition temperature of its homopolymer is lower than 0 ℃ (more preferably -20 ℃ or less, more preferably -40 ℃ or less); and 0.1 to 20% by weight (more preferably 1 to 15% by weight, more preferably 2.5 to 10% by weight, more preferably 4% by weight or more and less than 10% by weight) % by weight) of the high Tg monomer (B), which is at least one selected from the group consisting of (meth)acrylic acid alkyl ester (b1) and (meth)acryloyl group-containing monomer (b2) 1 type, wherein the glass transition temperature of the homopolymer of the above-mentioned alkyl (meth)acrylate (b1) is 0°C or higher (more Preferably it is 20°C or higher, more preferably 40°C or higher), and the glass transition temperature of the homopolymer of the aforementioned (meth)acryloyl group-containing monomer (b2) is 0°C or higher (more preferably 20°C or higher, and More preferably, it is 40°C or higher) and has a heterocyclic ring.

In addition, when the said alkyl (meth)acrylate (b1) and the said (meth)acryloyl group containing monomer (b2) are used together, it will be based on the total weight %.

Examples of the alkyl (meth)acrylate (A) include ethyl acrylate (Tg: -24°C), n-butyl acrylate (Tg: -50°C), and n-pentyl methacrylate (Tg: -5°C) ), n-hexyl acrylate (Tg: -57°C), n-hexyl methacrylate (Tg: -5°C), n-octyl acrylate (Tg: -65°C), n-octyl methacrylate (Tg: -20°C) ), n-nonyl acrylate (Tg: -58°C), n-lauryl acrylate (Tg: -3°C), n-lauryl methacrylate (Tg: -65°C), n-tetradecyl methacrylate (Tg: -72°C), isopropyl acrylate (Tg: -3°C), isobutyl acrylate (Tg: -40°C), isooctyl acrylate (Tg: -58°C), isooctyl methacrylate (Tg: -45°C), 2-ethylhexyl acrylate (Tg: -70°C), 2-ethylhexyl methacrylate (Tg: -10°C), and the like. These may be used alone or may be used in combination. Among these, at least one selected from ethyl acrylate, n-butyl acrylate, n-pentyl methacrylate, n-hexyl acrylate, and 2-ethylhexyl acrylate is preferably used, and n-butyl acrylate is more preferably used ester. In addition, the Tg (glass transition temperature) in each of the aforementioned parentheses is the Tg of the homopolymer obtained by polymerizing each monomer. The same applies to the following description.

Examples of the alkyl (meth)acrylate (b1) include methyl acrylate (Tg: 8°C), methyl methacrylate (Tg: 105°C), ethyl methacrylate (Tg: 65°C), acrylic acid n-propyl ester (Tg: 3°C), n-propyl methacrylate (Tg: 35°C), n-amyl acrylate (Tg: 22°C), propylene n-tetradecyl acid (Tg: 24°C), n-hexadecyl acrylate (Tg: 35°C), n-hexadecyl methacrylate (Tg: 15°C), n-octadecyl acrylate (Tg: 30°C) and Straight chain alkyl esters of (meth)acrylates such as n-octadecyl methacrylate (Tg: 38°C); tertiary butyl acrylate (Tg: 43°C), tertiary butyl methacrylate (Tg: 48°C) , branched alkyl esters of (meth)acrylates such as isopropyl methacrylate (Tg: 81°C) and isobutyl methacrylate (Tg: 48°C); cyclohexyl acrylate (Tg: 19°C), methyl methacrylate Cyclic (meth)acrylic acid cyclic alkyl esters such as cyclohexyl acrylate (Tg: 65°C), isobornyl acrylate (Tg: 94°C), and isobornyl methacrylate (Tg: 180°C). These may be used alone or may be used in combination. Among them, at least one selected from methyl acrylate, methyl methacrylate, ethyl methacrylate, isocampylate acrylate and isocampylate methacrylate is preferably used, and more preferably one selected from acrylic acid At least one of methyl ester, methyl methacrylate, and isobornyl acrylate.

環及嗎福林環等脂肪族雜環；吡咯環、咪唑環、吡唑環、

唑環、異

唑環、噻唑環、異噻唑環、吡啶環、嘧啶環、嗒

環及吡

環等芳香族雜環等。前述雜環可與(甲基)丙烯醯基直接鍵結，亦可透過連結基與(甲基)丙烯醯基鍵結。該等之中以脂肪族雜環為宜，更以嗎福林為宜。前述含(甲基)丙烯醯基單體(b2)可舉例如N-丙烯醯基嗎福林(Tg：145℃)等。該等可單獨使用或可組合使用。在該等之中，尤宜使用N-丙烯醯基嗎福林。 The aforementioned (meth)acryloyl group-containing monomer (b2) has a heterocyclic ring. Although the heterocyclic ring is not particularly limited, for example, an aziridine ring, an acridine ring, a pyrrolidine ring, a piperidine ring, a piperidine ring, a

Aliphatic heterocycle such as ring and mofolin ring; pyrrole ring, imidazole ring, pyrazole ring,

azole ring, iso

azole, thiazole, isothiazole, pyridine, pyrimidine, pyridine

Cyclopyridine

Aromatic heterocycles such as rings, etc. The aforementioned heterocycle may be directly bonded to the (meth)acryloyl group, or may be bonded to the (meth)acryloyl group through a linking group. Among them, aliphatic heterocycles are preferable, and morpholinos are more preferable. As said (meth)acryloyl group containing monomer (b2), N-acryloyl mofolin (Tg: 145 degreeC) etc. are mentioned, for example. These may be used alone or may be used in combination. Among these, N-acrylomorphine is particularly preferably used.

In order to improve adhesion, thermal conductivity, etc., the aforementioned (meth)propylene One or more kinds of various monomers can be introduced into the alkene-based polymer by copolymerization. Specific examples of the comonomers (except the aforementioned (meth)acryloyl group-containing monomer (b2)) include carboxyl group-containing monomers, hydroxyl group-containing monomers, nitrogen-containing monomers and aromatic group-containing monomers. Monomer, etc.

Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and the like. These may be used alone or may be used in combination.

Examples of hydroxyl-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate , 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate and (4-hydroxymethylcyclohexyl)-methyl acrylate, etc. These may be used alone or may be used in combination.

、乙烯基吡

、乙烯基吡咯、乙烯基咪唑、乙烯基

唑、乙烯基嗎福林、N-乙烯基羧酸醯胺類等。該等可單獨使用或可組合使用。 Nitrogen-containing monomers include, for example, vinyl-based monomers having a lactamide ring (for example, vinylpyrrolidone-based monomers such as N-vinylpyrrolidone, methylvinylpyrrolidone, etc.; amide ring, δ-lactamide ring and ε-lactamide ring and other lactam ring vinyl amide monomers, etc.); maleimide, N-cyclohexylmaleimide, Maleimide monomers such as N-phenylmaleimide; (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl ( Meth) acrylamide, N-hexyl (meth) acrylamide, N-methyl (meth) acrylamide, N-butyl (meth) acrylamide, N-butyl (meth) (N-substituted) amide monomers such as acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (meth) acrylamide, etc.; (meth) ethyl amine acrylate , Aminopropyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, tertiary butylaminoethyl (meth)acrylate, 3-(3-pyridyl)propyl ( (Meth)acrylic acid aminoalkyl-based monomers such as meth)acrylates; N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxygen Succinimide-based monomers such as hexamethylene succinimide and N-(meth)acryloyl-8-oxyoctamethylene succinimide; cyanogens such as acrylonitrile and methacrylonitrile Base (meth)acrylate monomers; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperidine

, vinylpyridine

, vinylpyrrole, vinylimidazole, vinyl

azoles, vinyl mofolin, N-vinyl carboxyamide, etc. These may be used alone or may be used in combination.

Examples of the aromatic group-containing monomer include benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, and the like. These may be used alone or may be used in combination.

In addition to the above monomers, monomers containing acid anhydride groups such as maleic anhydride and itaconic anhydride; caprolactone adducts of acrylic acid; styrene sulfonic acid or allyl sulfonic acid, 2-(methyl) sulfonic acid group containing sulfonic acid group such as acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, (meth)acrylate sulfopropyl ester or (meth)acrylamideoxynaphthalenesulfonic acid Monomers; 2-hydroxyethyl acryloyl phosphate and other monomers containing phosphoric acid groups, etc. These may be used alone or may be used in combination.

In addition, vinyl-based monomers such as vinyl acetate, vinyl propionate, styrene, α-methylstyrene, N-vinyl caprolactam, etc.; Acrylic monomer of epoxy group; (meth)acrylic acid polyethylene glycol ester, (meth)acrylic acid polypropylene glycol ester, (meth)acrylic acid methoxyethylene glycol, (meth)acrylic acid methoxy polypropylene Glycol acrylate monomers such as glycol ester; tetrahydrofurfuryl (meth)acrylate, fluoro (meth)acrylate, polysiloxane (meth)acrylate and 2-methoxyethylacrylate, etc. Acrylate monomers, etc. These may be used alone or may be used in combination.

From the viewpoint of enhancing the cohesion of the aforementioned (meth)acrylic polymer to more effectively suppress the generation of the aforementioned nano-slits, the aforementioned carboxyl-containing monomers, the aforementioned hydroxyl-containing monomers, and the aforementioned nitrogen-containing monomers are preferably selected from the group consisting of At least one polar monomer (except the aforementioned (meth)acryloyl group-containing monomer (b2)) is introduced into the aforementioned (meth)acrylic polymer by copolymerization, and the aforementioned carboxyl group-containing monomer is more preferably , The aforementioned hydroxyl-containing monomer and the aforementioned nitrogen-containing monomer are introduced into the aforementioned (meth)acrylic polymer by copolymerization. The aforementioned carboxyl group-containing monomer is preferably (meth)acrylic acid. The aforementioned hydroxyl group-containing monomer is preferably at least one selected from 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. The aforementioned nitrogen-containing monomer is preferably a vinyl-based monomer having a lactamide ring, more preferably the aforementioned vinylpyrrolidone-based monomer, and more preferably N-vinylpyrrolidone. By introducing the aforementioned nitrogen-containing monomer into the aforementioned (meth)acrylic polymer by copolymerization, the generation of nano-slits can be more effectively suppressed, and the durability of the adhesive layer at high temperature and/or high humidity can be improved at the same time (peel resistance).

The aforementioned (meth)acrylic polymer preferably contains 0.01 to 3% by weight of the aforementioned carboxyl group-containing monomer as a monomer unit, more preferably 0.05 to 1% by weight, and more preferably 0.1 to 0.5% by weight.

The aforementioned (meth)acrylic polymer preferably contains 0.01 to 1 wt % of the aforementioned hydroxyl-containing monomer as a monomer unit, more preferably 0.05 to 1 wt % % by weight, and more preferably 0.1 to 0.5% by weight.

The aforementioned (meth)acrylic polymer preferably contains 0.1 to 5% by weight of the aforementioned nitrogen-containing monomer as a monomer unit, more preferably 0.5 to 3% by weight, and more preferably 1.5 to 3% by weight.

The average molecular weight of the aforementioned (meth)acrylic polymer is not particularly limited, but the weight average molecular weight is preferably about 500,000 to 2,500,000. Various known methods can be employed for the production of the aforementioned (meth)acrylic polymer, and radical polymerization methods such as bulk polymerization, solution polymerization, and suspension polymerization can be appropriately selected. As a radical polymerization initiator, various well-known thing of azo type and peroxide type can be used. The reaction temperature is usually about 50 to 80° C., and the reaction time is set to 1 to 8 hours. In addition, the solution polymerization method is preferable among the above-mentioned production methods, and ethyl acetate, toluene, etc. are generally used as a solvent of a (meth)acrylic-type polymer.

唑啉系等。該等交聯劑可使用1種或可將2種以上組合使用。 A cross-linking agent can be blended with the aforementioned adhesive. Adhesion and durability can be improved by the cross-linking agent, and the reliability at high temperature can be maintained and the shape of the adhesive itself can be maintained. As the crosslinking agent, isocyanate-based, epoxy-based, peroxide-based, metal chelate-based,

oxazoline etc. These crosslinking agents may be used alone or in combination of two or more.

As the isocyanate-based crosslinking agent, an isocyanate compound can be used. Examples of the isocyanate compound include toluene diisocyanate, chlorophenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, ethylene diisocyanate, diphenylmethane diisocyanate, hydrogenated The addition of isocyanate monomers such as diphenylmethane diisocyanate and the addition of these isocyanate monomers to trimethylolpropane, etc. Isocyanate compounds; trimeric isocyanate compounds, biuret-type compounds, as well as those related to well-known polyether polyols or polyester polyols, acrylic polyols, polybutadiene polyols and polyisoprene polyols, etc. Urethane prepolymer isocyanates, etc. formed by addition reaction.

The above-mentioned isocyanate-based cross-linking agent can be used alone or in a mixture of two or more, and the overall content is preferably 0.01 to 2 parts by weight of the aforementioned isocyanate-based cross-linking agent relative to 100 parts by weight of the base polymer, and It is preferable to contain 0.02 to 2 parts by weight, and more preferably to contain 0.05 to 1.5 parts by weight. A crosslinking agent may be suitably contained in consideration of cohesive strength and resistance to peeling during a durability test.

Various peroxides can be used as the peroxide-based crosslinking agent. Peroxides include, for example, bis(2-ethylhexyl) peroxydicarbonate, bis(4-tertiary butylcyclohexyl) peroxydicarbonate, di-tertiary butyl peroxydicarbonate, tertiary butyl peroxyneodecanoate, tertiary hexyl peroxytrimethyl acetate, trimethyl ethyl tertiary butyl peroxide, dilauryl peroxide, di-n-octyl peroxide, 1,1 ,3,3-tetramethylbutylperoxyisobutyrate, 1,1,3,3-tetramethylbutylperoxy2-ethylhexanoate, bis(4-methylbenzyl) base) peroxide, dibenzoyl peroxide, tertiary butyl peroxyisobutyrate, etc. Among these, bis(4-tert-butylcyclohexyl)peroxydicarbonate, dilauryl peroxide, and dibenzoyl peroxide, which are excellent in cross-linking reaction efficiency, are also preferably used.

The aforementioned peroxides can be used alone or in combination of two or more, but the overall content is 0.01 to 2 parts by weight relative to 100 parts by weight of the base polymer, and preferably 0.04 to 1.5 parts by weight. parts by weight, more preferably 0.05 to 1 part by weight. It can be appropriately selected within this range to adjust processability, reworkability, crosslinking stability, peelability, and the like.

Also, the adhesive may contain a silane coupling agent. Durability can be improved by using a silane coupling agent. As the silane coupling agent, one having an arbitrary and appropriate functional group can be used. As a functional group, a vinyl group, an epoxy group, an amine group, a mercapto group, a (meth)acryloyloxy group, an acetylacetyl group, an isocyanate group, a styryl group, a polysulfide group etc. are mentioned specifically,. Specifically, for example, vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane and other vinyl-containing silane coupling agents; Oxypropoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4- Epoxy cyclohexyl) ethyl trimethoxy silane and other epoxy-containing silane coupling agents; γ-aminopropyl trimethoxy silane, N-β-(aminoethyl)-γ-aminopropyl methyl dimethyl dimethyl Oxysilane, N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane, γ-triethoxysilyl-N-(1,3-dimethylbutylene)propylamine, N-phenyl-γ-aminopropyltrimethoxysilane and other amine-containing silane coupling agents; mercapto-containing silane coupling agents such as γ-mercaptopropylmethyldimethoxysilane; p-styrene trimethoxysilane Silane coupling agent containing styryl group; silane coupling agent containing (meth)acrylic group such as γ-acryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltriethoxysilane ; 3-isocyanate propyl triethoxysilane and other silane coupling agents containing isocyanate groups; bis(triethoxysilylpropyl) tetrasulfide and other silane coupling agents containing polysulfide groups, etc.

The aforementioned silane coupling agents can be used alone, or two kinds of them can be used together. However, the overall content relative to 100 parts by weight of the base polymer, the aforementioned silane coupling agent is preferably 0.001~5 parts by weight, preferably 0.01~1 parts by weight, more preferably 0.02~1 parts by weight, and 0.05~1 parts by weight 0.6 parts by weight is preferred.

In addition, from the viewpoint of improving the reworkability, the above-mentioned adhesive may contain a rework enhancer. The aforementioned heavy-duty lifting agent is a chemical substance with polar groups, which is easy to interact with the glass interface and easy to segregate at the glass interface. Examples of the above-mentioned heavy industrial lifting agent include diols having alkaneoxy groups such as EO and PO, oligomers having perfluoroalkyl groups, and polyether compounds having reactive silicon groups. As the aforementioned polyether compound, for example, those disclosed in Japanese Patent Laid-Open No. 2010-275522 can be used.

The above-mentioned polyether compounds having reactive silicon groups can be, for example, MS polymers S203, S303, S810 manufactured by KANEKA; SILYL EST250, EST280; SAT10, SAT200, SAT220, SAT350, SAT400, EXCESTAR S2410, S2420 or S3430, etc.

The content of the heavy lifting agent is preferably 0.001 parts by weight or more, more preferably 0.01 parts by weight or more, more preferably 0.1 parts by weight or more, and preferably less than 10 parts by weight, more preferably 5 parts by weight relative to 100 parts by weight of the base polymer It is preferably not more than 2 parts by weight, more preferably not more than 2 parts by weight, and still more preferably not more than 1 part by weight. If the content of the heavy-duty enhancer is less than 0.001 parts by weight, it will be difficult to improve the heavy-duty of the adhesive layer, and if it is more than 10 parts by weight, the adhesive properties of the adhesive layer will tend to decrease.

The method of forming the adhesive layer can be produced, for example, by the following method: apply the above-mentioned adhesive to the separation member that has undergone peeling treatment, etc. on the film, and after drying to remove the polymerization solvent to form an adhesive layer, transfer to the polarizer side of the single-sided protective polarizing film (the state of FIG. 1 is a polarizer); or apply the above-mentioned adhesive and dry After removing the polymerization solvent and the like, the method of forming the adhesive layer on the polarizer side and the like are described above. In addition, one or more solvents other than the polymerization solvent may be appropriately added to the coating of the adhesive.

Polysiloxane release liners should be used for the separation parts that have been peeled off. In the step of coating the adhesive of the present invention on the backing material and drying it to form an adhesive layer, the method of drying the adhesive may be an appropriate and appropriate method depending on the purpose. A method of superheating and drying the above-mentioned coating film is preferably 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 within the above range, an adhesive having excellent adhesive properties can be obtained.

As the drying time, a suitable time can be appropriately adopted. The above 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 can be used for the formation method of the adhesive layer. Specifically, for example, roll coating, touch roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, and air knife coating may be mentioned. Cloth method, curtain coating method, lip coating method, extrusion coating method using a die coater, etc., etc.

When the aforementioned adhesive layer is exposed, the adhesive layer may be protected with a peel-treated sheet (separator) until ready for practical use.

As the constituent material of the separator, for example, plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films can be cited; Porous materials such as paper, cloth, and non-woven fabrics; suitable sheets such as meshes, foamed sheets, metal foils, and laminates thereof, etc., but from the point of view of excellent surface smoothness, it is suitable to use plastic film.

The plastic film is not particularly limited as long as it can protect the above-mentioned adhesive layer. Examples include polyethylene film, polypropylene film, polybutene film, polypentadiene film, polymethylpentene film, and polyvinyl chloride. Film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate copolymer film, etc.

The thickness of the aforementioned separation member is usually 5 to 200 μm, and preferably about 5 to 100 μm. The aforementioned separators can also be subjected to mold release and antifouling treatment using polysiloxane-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based mold release agents, silicon powder, etc., as well as coating type and kneading type. , Evaporation type and other antistatic treatment. In particular, by appropriately performing peeling treatments such as polysiloxane treatment, long-chain alkyl treatment, and fluorine treatment on the surface of the separator, the peelability from the adhesive layer can be further improved.

<Surface Protection Film>

A surface protective film can be provided on the single-sided protective polarizing film attached to the adhesive layer. The surface protection film usually has a base film and an adhesive layer, and protects the polarizer through the adhesive layer.

From the viewpoints of inspectability and manageability, the base film of the surface protection film can be selected from a film material with isotropy or nearly isotropy. Examples of the film material include polyester-based resins such as polyethylene terephthalate films, cellulose-based resins, acetate-based resins, polyether-based resins, Polycarbonate-based resins, polyamide-based resins, polyimide-based resins, polyolefin-based resins, and acrylic-based resins are transparent polymers. Among them, polyester-based resins are suitable. The base film can be used as a laminate of one or more film materials, or an extension of the aforementioned films can be used. The thickness of the base film is usually 500 μm or less, and preferably 10 to 200 μm.

The adhesives forming the adhesive layer of the surface protection film can be appropriately selected from (meth)acrylic polymers, polysiloxane polymers, polyesters, polyurethanes, polyamides, polyethers, fluorines and Polymers such as rubber-based polymers are used as adhesives for the base polymer. From the viewpoints of transparency, weather resistance, heat resistance, etc., an acrylic adhesive that uses an acrylic polymer as the base polymer is suitable. The thickness of the adhesive layer (dry film thickness) can be determined according to the required adhesive force. Usually about 1~100μm, preferably 5~50μm.

In addition, for the surface protection film, a peeling treatment layer can be provided on the opposite side of the base film where the adhesive layer is provided through a low-adhesion material such as polysiloxane treatment, long-chain alkyl treatment, and fluorine treatment.

<Other optical layers>

The single-sided protective polarizing film with the adhesive layer of the present invention can be used as an optical film laminated with other optical layers in actual use. The optical layer is not particularly limited, and one or more layers, such as a reflective plate, a semi-transmissive plate, a retardation plate (including wavelength plates such as 1/2 and 1/4), a viewing angle compensation film, etc., can be used to form Optical layers of liquid crystal display devices, etc. It is especially preferred to be a reflective polarizing film or a semi-transmissive polarizing film formed by laminating a reflective plate or a semi-transmissive reflective plate on the single-sided protective polarizing film with the adhesive layer of the present invention, and the single-sided protective polarizing film with the adhesive layer. Film Relaminated Phase Difference Plate elliptical polarizing film or circular polarizing film, a wide viewing angle polarizing film formed by laminating a single-sided protective polarizing film with an adhesive layer and a viewing angle compensation film, or a single-sided protective polarizing film with an adhesive layer and then laminated to increase the viewing angle. Polarizing film made of bright film.

The optical film formed by laminating the above-mentioned optical layer on the single-sided protective polarizing film with the adhesive layer can also be formed by sequentially laminating in the manufacturing process of liquid crystal display devices, etc., but the optical film is pre-laminated to form an optical film It has advantages in terms of quality stability and assembly operations, and has the advantage of improving the manufacturing steps of liquid crystal display devices and the like. A suitable bonding mechanism such as an adhesive layer can be used for lamination. When the above-mentioned single-sided protective polarizing film with the adhesive layer and other optical layers are attached, their optical axes can be set to an appropriate arrangement angle according to the desired retardation characteristics and the like.

The single-sided protective polarizing film or optical film with the adhesive layer of the present invention can be suitably used in the formation of various image display devices such as liquid crystal display devices and organic EL display devices. The formation of the liquid crystal display device can be carried out according to conventional techniques. That is, a liquid crystal display device is generally formed by appropriately assembling structural components such as a liquid crystal element, a single-sided protective polarizing film or an optical film with an adhesive layer, and an optional lighting system, and incorporating them into a driving circuit, etc., but in this case The invention is not particularly limited except for the use of the single-sided protective polarizing film or the optical film with the adhesive layer of the present invention, and conventional knowledge shall prevail. For the liquid crystal cell, any type such as IPS type, VA type, etc. can also be used, but the IPS type is particularly desirable.

A liquid crystal display device that can form a single-sided protective polarizing film or an optical film with an adhesive layer arranged on one or both sides of the liquid crystal element A suitable liquid crystal display device such as a backlight or a reflector is used for the lighting system. At this time, the single-sided protective polarizing film or optical film of the present invention with the adhesive layer can be arranged on one side or both sides of the liquid crystal cell. When the single-sided protective polarizing film or the optical film with the adhesive layer is arranged on both sides, the same may be the same or different. In addition, when forming a liquid crystal display device, suitable parts such as a diffuser plate, an anti-glare layer, an anti-reflection film, a protective plate, a solar array, a lens array sheet, a light diffuser plate, a backlight, etc. can be arranged at appropriate positions. layer or more than 2 layers.

<Continuous Manufacturing Method of Image Display Device>

The above-mentioned image display device is preferably manufactured by a continuous manufacturing method (roll-to-roll method), and the continuous manufacturing method includes the following steps: releasing the roll body (roll material) of the single-sided protective polarizing film with the adhesive layer of the present invention. The single-sided protective polarizing film with the adhesive layer, which is delivered and conveyed by the separating element, is continuously attached to the surface of the image display panel through the adhesive layer. Since the single-sided protective polarizing film with the adhesive layer of the present invention is a very thin film, if the method of cutting into sheets (sheet cutting) and then attaching them to the image display panel (also referred to as "sheet-to-panel method"), it is difficult to handle when conveying the sheet or attaching to the display panel, so that the single-sided protective polarizing film (sheet) with the adhesive layer is subjected to The risk of large mechanical shocks (eg bending due to adsorption, etc.) is increased. In order to reduce such a risk, countermeasures such as the use of a surface protective film with a thickness of 50 μm or more of the thickness of the base material are required separately. However, according to the roll-to-face method, it is not necessary to cut the single-sided protective polarizing film with the adhesive layer into a sheet (slice cut), but to separate the film in a continuous state. The parts are stably transported from the roller to the image display panel and directly attached to the image display panel, so the above risks can be greatly reduced without using a thicker surface protection film. As a result, combined with the use of an adhesive layer that has been controlled so that the film thickness and storage elastic modulus satisfy a predetermined relationship to mitigate mechanical impact, an image display panel with effectively suppressed nano-slit formation can be continuously produced at high speed.

FIG. 5 is a schematic diagram showing an example of a continuous manufacturing system of a liquid crystal display device using the web-to-surface method. As shown in FIG. 5 , the continuous manufacturing system 100 of liquid crystal display devices includes a conveying unit X that conveys a string of liquid crystal display panels P, a first polarizing film supply unit 101a, a first bonding unit 201a, and a second polarizing film supply unit 101b and the second bonding portion 201b. In addition, the roll body (first roll) 20a for the single-side protective polarizing film with the first adhesive layer and the roll (second roll) 20b for the single-side protective polarizing film with the second adhesive layer It is used in the aspect described in FIG. 1 which has an absorption axis in the longitudinal direction.

(Conveying Department)

The conveyance unit X conveys the liquid crystal display panel P. The conveyance part X is comprised with several conveyance rollers, adsorption|suction plates, etc., and is comprised. The conveying part X includes an arrangement replacement part 300 between the first bonding part 201a and the second bonding part 201b, and the arrangement replacement part 300 is used to replace the long side and the short side of the liquid crystal display panel P with respect to the liquid crystal display panel P The arrangement relationship in the conveying direction (for example, the liquid crystal display panel P is rotated horizontally by 90°). Thereby, the single-sided protective polarizing film 21a of the first adhesive layer and the single-sided protective polarizing film 21b of the second adhesive layer can be bonded to the liquid crystal display panel P in a cross-polarized relationship.

(1st polarizing film supply unit)

The first polarizing film supply part 101a continuously supplies the single-sided protective polarizing film (surface protection film attached) 21a with the first adhesive layer, which is released from the first roll 20a and conveyed by the separator 5a, to the first bonding part 201a. The 1st polarizing film supply part 101a has the 1st discharge part 151a, the 1st cutting part 152a, the 1st peeling part 153a, the 1st winding part 154a, a plurality of conveying roller parts, integration parts such as dancer rollers, and the like.

The first release part 151a has a release shaft on which the first roll 20a can be installed, and can release the single-sided protective polarizing film 21a with the tape-shaped adhesive layer provided with the separator 5a from the first roll 20a.

The first cutting portion 152a has a cutting mechanism such as a cutter and a laser device, and a suction mechanism. The first cutting part 152a can cut the single-sided protective polarizing film 21a of the strip-shaped first adhesive layer in the width direction at a predetermined length while retaining the separator 5a. However, a single-sided protective polarizing film 21a (an optical film roll with a cut mark) having a tape-like adhesive layer formed with a plurality of cut lines in a predetermined length in the width direction is laminated on the use separator 5a as the first film. In the case of one roll 20a, the first cutting portion 152a is not required (the same applies to the second cutting portion 152b to be described later).

The 1st peeling part 153a reverses the separator 5a inward, and peels the single-sided protective polarizing film 21a of the 1st adhesive bond layer from the separator 5a. The 1st peeling part 153a is mentioned, for example, a wedge-shaped member, a roller, etc. are mentioned.

The 1st winding part 154a winds up the separator 5a of the single-sided protective polarizing film 21a from which the 1st adhesive layer was peeled off. The first winding portion 154a has a winding shaft, and the winding shaft is provided with a roller for winding the separation member 5a.

(The first fitting part)

The first bonding portion 201a continuously bonds the single-sided protective polarizing film 21a with the first adhesive layer peeled off through the first peeling portion 153a and the adhesive layer through the single-sided protective polarizing film 21a with the first adhesive layer. To the liquid crystal display panel P conveyed by the conveyance part X (1st bonding process). The first bonding portion 81 includes a pair of bonding rollers, and at least one of the bonding rollers is configured as a drive roller.

(Second polarizing film supply unit)

The second polarizing film supply part 101b continuously supplies the single-sided protective polarizing film (surface protective film attached) 21b with the second adhesive layer that is released from the second roll 20b and conveyed by the separator 5b to the second bonding part 201b. The second polarizing film supply part 101b has a second release part 151b, a second cutting part 152b, a second peeling part 153b, a second winding part 154b, an accumulation part of a plurality of conveying roller parts, dancer rollers, and the like. In addition, the second releasing portion 151b, the second cutting portion 152b, the second peeling portion 153b, and the second winding portion 154b are connected to the first releasing portion 151a, the first cutting portion 152a, the first peeling portion 153a, The first winding portion 154a has the same configuration and function.

(Second fitting part)

The second bonding portion 201b continuously bonds the single-side protective polarizing film 21b with the second adhesive layer peeled off through the second peeling portion 153b and the adhesive layer through the single-side protective polarizing film 21b with the second adhesive layer. To the liquid crystal display panel P conveyed by the conveyance part X (2nd bonding process). The second bonding portion 201b includes a pair of bonding rollers, and at least one of the bonding rollers is configured as a drive roller.

Example

The following examples are given to illustrate the present invention, but the present invention does not It is limited by the examples shown below. In addition, the parts and % in each example are based on weight. Hereinafter, all room temperature storage conditions not specified are 23° C. and 65% RH.

<Production of single-sided protective polarizing film A>

(Production of polarizer)

Corona treatment was applied to one side of the substrate of amorphous isophthalic acid copolyethylene terephthalate (IPA-copolymerization-PET) film (thickness: 100 μm) with a water absorption rate of 0.75% and a Tg of 75 °C. The corona treated surface was coated at 25°C with a ratio of 9:1 containing polyvinyl alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetylacetate-modified PVA (polymerization degree 1200, acetonitrile Acetyl group modification degree of 4.6%, saponification degree of 99.0 mol% or more, Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gohsefimer Z200") aqueous solution was dried to form a PVA-based resin layer with a thickness of 11 μm, and a laminate was produced.

The obtained layered body was uniaxially stretched at a free end by 2.0 times in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds in a 120° C. oven (aerial-assisted stretching treatment).

Next, the layered body was immersed in an insolubilization bath (a boric acid aqueous solution obtained by blending 4 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 30°C for 30 seconds (insolubility treatment).

Next, immerse it in a dyeing bath with a liquid temperature of 30° C. and adjust the iodine concentration and the immersion time at the same time, so that the polarizing plate reaches a predetermined transmittance. In the present example, it was immersed in an iodine aqueous solution obtained by blending 0.2 parts by weight of iodine and 1.0 parts by weight of potassium iodide with respect to 100 parts by weight of water for 60 seconds (dyeing treatment).

Next, it was immersed for 30 seconds in a crosslinking bath (a boric acid aqueous solution obtained by mixing 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 (crosslinking treatment ).

Then, the layered body was immersed in an aqueous solution of boric acid (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) at a liquid temperature of 70° C. on rolls with different peripheral speeds. Uniaxial stretching was performed between the cylinders in the longitudinal direction (longitudinal direction) so that the total stretching ratio was 5.5 times (underwater stretching treatment).

Then, the layered body was immersed in a cleaning bath (aqueous solution obtained by mixing 4 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 30°C (cleaning treatment).

Through the above procedure, an optical thin film laminate including a polarizer having a thickness of 5 μm and a boric acid content of 16% was obtained. The content of boric acid in the polarizer was measured by the following method.

About the obtained polarizer, the peak value of boric acid (665 cm ⁻¹ ) was measured with a Fourier transform infrared spectrophotometer (FTIR) (manufactured by Perkin Elmer, trade name “SPECTRUM2000”) by attenuated total reflection spectroscopy (ATR) measurement using polarized light as measurement light. ) intensity and reference peak (2941 cm ^-1 ) intensity. From the obtained boric acid peak intensity and the reference peak intensity, the boric acid content index was calculated by the following formula, and the boric acid content (% by weight) was determined by the following formula from the calculated boric acid content index.

(Boric acid amount index)=(Intensity of boric acid peak at 665cm ^-1 )/(Intensity of reference peak at 2941cm ^-1 )

(boric acid content (wt%))=(boric acid content index)×5.54+4.1

(Production of transparent protective film)

Transparent protective film: Corona treatment was applied to the easily bondable surface of the (meth)acrylic resin film having a thickness of 40 μm and having a lactone ring structure and used.

(Apply to the production of adhesive for transparent protective film)

40 parts by weight of N-hydroxyethyl acrylamide (HEAA), 60 parts by weight of acryl molyfrin (ACMO), and 3 parts by weight of a photoinitiator "IRGACURE 819" (manufactured by BASF) were blended to prepare UV curable adhesive.

(Production of single-sided protective polarizing film A)

On the surface of the polarizer of the above-mentioned optical film laminate, the above-mentioned ultraviolet curable adhesive was applied so that the thickness of the adhesive layer after curing was 0.5 μm, and the above-mentioned transparent protective film was adhered, and then irradiated as active energy. The ultraviolet rays of the wire harden the adhesive. The ultraviolet irradiation was performed using a metal halide lamp filled with gallium, irradiation device: Light HAMMER10 manufactured by Fusion UV Systems, Inc., bulb: V bulb, peak illuminance: 1600 mW/cm ² , cumulative irradiation dose 1000/mJ/cm ² (wavelength 380 to 440 nm), and the ultraviolet illuminance was measured using the Sola-Check system manufactured by Solatell. Next, the amorphous PET base material was peeled off, and a single-sided protective polarizing film A using a thin polarizer was produced. Using the obtained single-sided protective polarizing film A, after measuring the single transmittance T and polarization degree P of the polarizer by the following method, the single transmittance T of the polarizer is 42.8%, and the polarization degree P of the polarizer is 99.99 %.

Using a spectroscopic transmittance meter with an integrating sphere (Shirai Murakami Dot-3c) of the Institute of Color Technology was used to measure the single transmittance T and the degree of polarization P of the polarizer of the single-sided protective polarizing film A obtained.

In addition, the degree of polarization P is the transmittance when two identical single-sided protective polarizing films A are superimposed with their transmission axes parallel to each other (parallel transmittance: Tp) and the transmittance when the two transmission axes are orthogonally superimposed (Vertical transmittance: Tc) was obtained by applying the following formula. Polarization degree P(%)={(Tp-Tc)/(Tp+Tc)} ^1/2 ×100

Each transmittance is represented by a Y value obtained by correcting the luminous efficacy with a 2-degree field of view (C light source) according to JIS Z8701, with the complete polarization obtained by passing through a Glan-Taylor polarizer as 100%.

<Production of single-sided protective polarizing film B>

The polyvinyl alcohol film with a thickness of 80 μm was dyed in an iodine solution with a concentration of 0.3% at 30° C. for 1 minute between rollers with different speed ratios and stretched to 3 times. Then, the film was immersed in an aqueous solution containing boric acid at a concentration of 4% and potassium iodide at a concentration of 10% for 0.5 minutes at 60° C. and stretched so that the total stretching ratio was 6 times or more. Next, the film was immersed in an aqueous solution containing potassium iodide having a concentration of 1.5% at 30° C. for 10 seconds, washed, and then dried at 50° C. for 4 minutes to obtain a polarizer with a thickness of 20 μm. The saponified acrylic resin film (transparent protective film) of 40 μm was attached to one side of the polarizer with an adhesive, and a single-side protective polarizing film B was produced.

<Forming the Adhesive Layer>

(Preparation of Acrylic Adhesive A)

Will contain 91.8 parts of n-butyl acrylate, 6 parts of methyl methacrylate, 1.5 parts of N-vinylpyrrolidone, 0.2 parts of acrylic acid and 0.5 parts of The monomer mixture of 4-hydroxybutyl acrylate was fed into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen introduction pipe, and a cooler. Next, 0.15 part of 2,2′-azobisisobutyronitrile as a polymerization initiator was fed with ethyl acetate with respect to 100 parts of the aforementioned monomer mixture (solid content), and nitrogen gas was introduced while stirring slowly. After nitrogen replacement, the liquid temperature in the flask was maintained at about 60°C, and the polymerization reaction was performed for 7 hours. Then, ethyl acetate was added to the obtained reaction liquid, and the acrylic polymer solution whose solid content was adjusted to a concentration of 20% and a weight average molecular weight of 1,300,000 was prepared.

The weight average molecular weight (Mw) of the said acrylic polymer was measured using the GPC apparatus (HLC-8220GPC) by Tosoh (Tosoh) Co., Ltd. product. The measurement conditions are as follows.

Sample concentration: 0.2 mass % (THF solution)

Sample injection volume: 10μl

Elution solution: THF

Flow rate: 0.6ml/min

Measurement temperature: 40℃

Column: sample column; TSKguardcolumn SuperHZ-H (1)+TSKgel SuperHZM-H (2)

Reference column; TSKgel SuperH-RC (1 piece)

Detector: Differential Refractometer (RI)

The weight average molecular weight is determined in terms of polystyrene.

With respect to 100 parts of solid content of the prepared acrylic polymer solution, 0.17 part of isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, trade name "TAKENATE D160N"), 0.25 part of excess Oxide-based crosslinking agent (manufactured by NOF Corporation, trade name "NYPER BMT") and 0.2 part of an acetylacetyl group-containing silane coupling agent (manufactured by Soken Chemical Co., Ltd., trade name "A-100") were prepared. Acrylic adhesive A is produced.

(Preparation of Acrylic Adhesives B~S)

An acrylic adhesive was prepared by preparing a solution of an acrylic polymer in the same manner, except that the monomer composition at the time of preparing the above-mentioned acrylic adhesive A was changed as shown in Table 1 and the polymerization conditions were adjusted. B~S.

(Forming Adhesive Layers A~S)

Next, the prepared acrylic adhesives A~S were uniformly coated on the surface of the polyethylene terephthalate film (separation film) treated with the polysiloxane release agent by a spray coater. , and dried in an air circulation constant temperature oven at 155° C. for 1 minute, and the adhesive layers A~S with a thickness of 20 μm were respectively formed on the surface of each separation film.

The compounds in Table 1 are as follows.

BA: n-butyl acrylate (Tg: -50°C)

MMA: methyl methacrylate (Tg: 105°C)

MA: methyl acrylate (Tg: 8°C)

IBXA: Isobornyl Acrylate (Tg: 94°C)

ACMO: N-acrylomorphine (Tg: 145°C)

NVP: N-Vinylpyrrolidone

AA: Acrylic

4HBA: 4-hydroxybutyl acrylate

Examples 1 to 18, Comparative Examples 1 to 3

<Preparation of single-sided protective polarizing film with adhesive layer>

The produced adhesive layers A to S are respectively attached to the polarizer side of the produced single-sided protective polarizing film A or B, and a single-sided protective polarizing film with the adhesive layer is produced.

The following measurements and evaluations were performed on the adhesive layer and the single-sided protective polarizing film with the adhesive layer obtained above. The results are listed in Table 2.

<Measurement of the peak value of storage elastic modulus and loss elastic modulus>

The peak values of storage elastic modulus and loss elastic modulus of the produced adhesive layers A~S at -40°C and 85°C were measured by a viscoelasticity spectrometer (trade name: RSA-II) manufactured by Rheometric Company. conduct. The measurement conditions were set as a frequency of 1 Hz, a sample thickness of 2 mm, a crimping weight of 100 g, a heating rate of 5°C/min, and a temperature range of -70°C to 150°C.

<Suppression of Nano Slit Generation: Guitar Shrapnel Test>

The single-sided protective polarizing film with the adhesive layer obtained in the Examples and Comparative Examples was cut into a size of 50 mm×150 mm (50 mm in the direction of the absorption axis), and used as Sample 11. The sample 11 was used by bonding the surface protective film 6 produced by the following method on the protective film 2 side.

(Surface protection film for testing)

94 parts by mass of 2-ethylhexyl acrylate (2EHA), 1 part by mass of N,N-diethylacrylamide (DEAA), and 1 part by mass of ethoxydiethylene glycol acrylate (EDE) , 4 parts by mass of 4-hydroxybutyl acrylate (HBA), 0.2 parts by mass of 2,2'-azobisisobutyronitrile as a polymerization initiator, and 150 parts by mass of ethyl acetate, which were fed into the , thermometer, nitrogen inlet tube, Nitrogen gas was introduced into the four-necked flask of the cooler while stirring slowly, the liquid temperature in the flask was maintained at about 60° C., and a polymerization reaction was performed for 5 hours to prepare an acrylic polymer solution (40% by mass). The weight average molecular weight of the aforementioned acrylic polymer was 570,000, and the glass transition temperature (Tg) was -68°C.

The aforementioned acrylic polymer solution (40 mass %) was diluted to 20 mass % with ethyl acetate, and 2 mass parts (solid content 2 mass parts) was added to 500 mass parts (solid content 100 mass parts) of this solution A trimeric isocyanate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX: C/HX), 2 parts by mass (solid content 0.02 parts by mass) of dilauric acid as a crosslinking catalyst butyl tin (1 mass % ethyl acetate solution) was mixed and stirred, and the acrylic adhesive solution was prepared.

The aforementioned acrylic adhesive solution was coated on a transparent polyethylene terephthalate (PET) film (polyester film) with a thickness of 38 μm, and heated at 130° C. for 1 minute to form an adhesive layer with a thickness of 15 μm, and A surface protective film is produced.

Next, as shown in the conceptual diagram of FIG. 3(A) and the cross-sectional view of FIG. 3(B) , the release sheet (separator) is peeled off from the sample 11 and attached to the glass plate through the exposed adhesive layer 4 20 on. Next, a load of 200 g was applied to the central part of the sample 11 (the surface protection film 6 side) with a guitar shrapnel (manufactured by HISTORY, model "HP2H (HARD)"), and the load of the sample 11 was perpendicular to the absorption axis of the polarizer 1. Repeatedly back and forth 50 times of load loading with a distance of 100mm. The aforementioned load application is carried out at 1 place. In addition, the above-mentioned load application is performed at a high speed (5 m/min) and a low speed (1 m/min), respectively.

Next, after the sample 11 was left to stand in an environment of 80° C. for 1 hour, the presence or absence of cracks in the sample 11 with light leakage was confirmed according to the following criteria.

(In the case of running at high speed)

◎: 0~10

○: 11~15

△: 16~30

×: 31 or more

(When running at low speed)

◎: 0

○: 1~3

△: 4~5 pieces

×: 6 or more

4 is an example of a microscopic photograph of the surface of the polarizing film confirming the following indicators of light leakage cracks (nano slits a) of the single-sided protective polarizing film 11 with the adhesive layer in the guitar dome test. In FIG. 4(A) , no light leakage crack caused by the nano-slit a is confirmed. In addition, FIG. 4(B) shows the case of light leakage cracks caused by three nano-slits a in the direction of the absorption axis of the polarizer by heating. Figure 4 shows the sample with nanoslits observed under an interference phase contrast microscope. When photographing the sample, the sample produced by the nano-slit is placed on the lower side (transmission side of the light source) of the sample produced by the nano-slit in a manner of orthogonal polarization, and the sample is observed with transmitted light.

<Evaluation of Durability>

Peel off the release film of the single-sided protective polarizing film (37 inches) attached to the adhesive layer, and use a laminating machine to attach it to an alkali-free glass (Corning Corporation) with a thickness of 0.7 mm. Secretary system, EG-XG). Next, autoclave treatment was performed at 50° C. and 0.5 MPa for 15 minutes, so that the polarizing film was completely adhered to the alkali-free glass. Next, it was put into a heating oven at 80°C (heating) and a constant temperature and humidity machine at 60°C/90%RH (humidification), and after 500 hours, the following criteria were used to evaluate the presence or absence of peeling of the polarizing plate .

⊚: No peeling was observed at all.

○: Peeling was observed to such an extent that it could not be visually recognized.

(triangle|delta): Micro peeling which can be confirmed visually is confirmed.

×: Remarkable peeling was observed.

It can be seen from Table 2 that the single-sided protective polarizing films of the adhesive layers of Examples 1 to 18 are not prone to cracks when loaded at a high speed or when loaded at a low speed. Excellent durability (peeling resistance) at high temperature and high humidity. On the other hand, it can be seen that the single-sided protective polarizing films with the adhesive layers of Comparative Examples 1 to 3 will generate a large number of cracks regardless of whether they are loaded at a high speed or loaded at a low speed. In addition, after comparing the single-sided protective polarizing film with the adhesive layer of Example 14 and the single-sided protective polarizing film with the adhesive layer of Example 17, it can be seen that the use of a nitrogen-containing monomer as a monomer unit is used. The single-sided protective polarizing film with the adhesive layer of Example 14 using acrylic polymer to form the adhesive layer is less prone to cracks, and has excellent durability (peeling resistance) at high temperature and high humidity. In addition, it can be seen from Example 14 and Example 18 that the single-sided protective polarizing film with the adhesive layer of the present invention is not prone to cracks regardless of whether the thickness of the polarizer is thin or thick.

industrial availability

The single-sided protective polarizing film with the adhesive layer of the present invention can be used for image display devices such as liquid crystal display devices (LCD), organic EL display devices, etc. alone or as an optical film formed by laminating them.

1‧‧‧Polarizer

2‧‧‧Protective film

3‧‧‧Adhesive layer

4‧‧‧Adhesive layer

5‧‧‧Separate parts

6‧‧‧Surface protection film

10‧‧‧Single-sided protective polarizing film

11‧‧‧One-sided protective polarizing film with adhesive layer

Claims (25)

A single-sided protective polarizing film with an adhesive layer, characterized in that it has a single-sided protective polarizing film with a protective film only on one side of a polarizer, and an adhesive directly on the polarizer side of the single-sided protective polarizing film The layer or the intervening coating layer has an adhesive layer; and the storage elastic modulus of the adhesive layer at -40°C is 7.0×10 ⁷ Pa or more; the adhesive layer contains a (meth)acrylic polymer as a A base polymer, and the aforementioned (meth)acrylic polymer contains the following monomer units: 70% by weight or more of alkyl (meth)acrylate (A), and the glass transition temperature of the homopolymer is lower than 0 ℃; and 0.1 to 20% by weight of high Tg monomer (B), which is selected from the group consisting of (meth)acrylic acid alkyl ester (b1) and (meth)acryloyl group-containing monomer (b2) At least one of the group, the glass transition temperature of the homopolymer of the aforementioned alkyl (meth)acrylate (b1) is 0°C or higher, and the homopolymer of the aforementioned (meth)acryloyl group-containing monomer (b2) The glass transition temperature of the material is 0°C or higher and it has a heterocyclic ring. The single-sided protective polarizing film with an adhesive layer as claimed in claim 1, wherein the peak value of the attrition elastic modulus of the adhesive layer is above -45°C. The single-sided protective polarizing film with an adhesive layer according to claim 1 or 2, wherein the storage elastic modulus of the adhesive layer at 85°C is 5.5×10 ⁴ Pa or more and 1.4×10 ⁵ Pa or less. Single-sided protection of the adhesive layer according to claim 1 or 2 Polarizing film, wherein the aforementioned (meth)acrylic polymer contains, as a monomer unit, a polar monomer other than the aforementioned (meth)acryloyl group-containing monomer (b2), and the polar monomer system is selected from the group consisting of nitrogen-containing monomers. At least one of the group consisting of a monomer, a carboxyl group-containing monomer and a hydroxyl group-containing monomer. The single-sided protective polarizing film with an adhesive layer according to claim 4, wherein the nitrogen-containing monomer is a vinyl-based monomer having an amide ring. The single-sided protective polarizing film with an adhesive layer according to claim 5, wherein the vinyl-based monomer having a lactamide ring is a vinylpyrrolidone-based monomer. The single-sided protective polarizing film with an adhesive layer according to claim 6, wherein the vinylpyrrolidone-based monomer is N-vinylpyrrolidone. The single-sided protective polarizing film with an adhesive layer according to claim 4, wherein the (meth)acrylic polymer contains 0.1 to 5% by weight of the nitrogen-containing monomer as a monomer unit. The single-sided protective polarizing film with an adhesive layer according to claim 4, wherein the (meth)acrylic polymer contains 0.01 to 3% by weight of the carboxyl group-containing monomer as a monomer unit. The single-sided protective polarizing film with an adhesive layer according to claim 4, wherein the (meth)acrylic polymer contains 0.01 to 1% by weight of the hydroxyl-containing monomer as a monomer unit. The single-sided protective polarizing film with an adhesive layer according to claim 1 or 2, wherein the thickness of the polarizer is 12 μm or less. The single-sided protective polarizing film with an adhesive layer according to claim 1 or 2, wherein the polarizer contains a polyvinyl alcohol-based resin, and is configured such that the optical properties represented by the monomer transmittance T and the degree of polarization P satisfy the following formula Condition: P>-(10 ^0.929T-42.4 -1)×100 (only, T<42.3), or P≧99.9 (only, T≧42.3). The single-sided protective polarizing film with an adhesive layer according to claim 1 or 2, wherein the polarizer contains 25% by weight or less of boric acid relative to the total amount of the polarizer. As claimed in claim 1 or 2, the single-sided protective polarizing film with an adhesive layer is provided with a separator on the above-mentioned adhesive layer. As claimed in claim 14, the single-sided protective polarizing film with an adhesive layer is a wound body. An image display device having a single-sided protective polarizing film with an adhesive layer as claimed in any one of claims 1 to 13. A continuous manufacturing method of an image display device, comprising the steps of: releasing the above-mentioned adhesive layer from the roll body of the above-mentioned single-sided protective polarizing film with the above-mentioned adhesive layer as claimed in claim 15 and conveyed by the above-mentioned separating member The single-sided protective polarizing film is continuously attached to the surface of the image display panel through the aforementioned adhesive layer. An adhesive, characterized in that: it is used as a material for forming an adhesive layer, and the adhesive layer is provided on the polarizer side of a single-sided protective polarizer film having a protective film on only one side of the polarizer; and, the aforementioned The adhesive contains at least a (meth)acrylic polymer, and the (meth)acrylic polymer contains the following as monomer units: 70% by weight or more of alkyl (meth)acrylate (A), the glass transition temperature of its homopolymer is lower than 0 ℃; and 0.1 to 20% by weight of high Tg monomer (B), which is selected from At least one of the group consisting of (meth)acrylic acid alkyl ester (b1) and (meth)acryloyl group-containing monomer (b2), the above-mentioned (meth)acrylic acid alkyl ester (b1) is at least one kind The glass transition temperature of the polymer is 0°C or higher, and the glass transition temperature of the homopolymer of the (meth)acryloyl group-containing monomer (b2) is 0°C or higher and has a heterocyclic ring. The adhesive of claim 18, wherein the (meth)acrylic polymer contains a polar monomer other than the (meth)acryloyl group-containing monomer (b2) as a monomer unit, and the polar monomer system is selected from the group consisting of At least one of the group consisting of nitrogen-containing monomers, carboxyl-containing monomers and hydroxyl-containing monomers. The adhesive of claim 19, wherein the aforementioned nitrogen-containing monomer is a vinyl-based monomer having a lactamide ring. The adhesive of claim 20, wherein the aforementioned vinyl-based monomer having a lactamide ring is a vinylpyrrolidone-based monomer. The adhesive of claim 21, wherein the vinylpyrrolidone is a monomeric system of N-vinylpyrrolidone. The adhesive according to any one of claims 18 to 22, wherein the (meth)acrylic polymer contains 0.1 to 5% by weight of the nitrogen-containing monomer as a monomer unit. The adhesive according to any one of claims 18 to 22, wherein the (meth)acrylic polymer contains 0.01 to 3% by weight of the carboxyl group-containing monomer as a monomer unit. The adhesive of any one of claims 18 to 22, wherein The aforementioned (meth)acrylic polymer contains 0.01 to 1% by weight of the aforementioned hydroxyl group-containing monomer as a monomer unit.

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