WO2020003857A1

WO2020003857A1 - Single-side-protected polarization film with adhesive layer, image display device, and continuous production method therfor

Info

Publication number: WO2020003857A1
Application number: PCT/JP2019/021065
Authority: WO
Inventors: 藤田　雅人; 有森本; 卓江原; 雄祐外山
Original assignee: 日東電工株式会社
Priority date: 2018-06-26
Filing date: 2019-05-28
Publication date: 2020-01-02
Also published as: CN112119332B; CN112119332A; TWI812726B; JP2020003576A; TW202000823A; KR20210023976A; JP7142497B2

Abstract

The objective of the present invention is to provide a single-side-protected polarization film with an adhesive layer wherein the film has excellent initial rework ability, durability and electric conduction stability under a high-temperature and/or high-humidity environment and is also not readily released from a glass substrate, or the like, even when exposed to an environment in which dew condensation arises. This single-side-protected polarization film with an adhesive layer comprises: a single-side-protected polarization film having a protective film only on one surface of a polarizer; and an adhesive layer, directly or via a coating layer, on the polarizer side of the single-side-protected polarization film. The adhesive layer contains a (meth)acrylic polymer as a base polymer, has a weight change rate of 1.1% or greater, an adhesive force P₀ of 10 N/25 mm or less prior to immersion in water, and an adhesive force P₁of 1.6 N/25 mm or more after immersion for two hours in water.

Description

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

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

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

粘着 When the polarizing film is attached to a liquid crystal cell or the like, an adhesive is usually used. In addition, since the polarizing film can be instantaneously fixed and has advantages such as not requiring a drying step to fix the polarizing film, the pressure-sensitive adhesive is provided in advance as a pressure-sensitive adhesive layer on one surface of the polarizing film. . That is, a polarizing film with an adhesive layer is used for attaching the polarizing film.

In addition, the polarizing film and the polarizing film with an adhesive layer may cause shrinkage of the polarizer under severe environments of thermal shock (for example, a heat shock test in which temperature conditions of −30 ° C. and 80 ° C. are repeated or a test under a high temperature of 100 ° C.). There is a problem that cracks (through cracks) are likely to occur in the entire absorption axis direction of the polarizer due to a change in stress. That is, the durability of the polarizing film or the polarizing film with the pressure-sensitive adhesive layer due to thermal shock in the harsh environment was not sufficient. In particular, from the viewpoint of thinning, the one-sided protective polarizing film with the pressure-sensitive adhesive layer using the one-sided protective polarizing film provided with the protective film only on one side of the polarizer was insufficient in durability due to the thermal shock. In addition, the through cracks caused by the thermal shock tended to occur when the size of the polarizing film was increased.

For example, in order to impart high durability in a high-temperature environment, the pressure-sensitive adhesive layer of the piece-protecting polarizing film with a pressure-sensitive adhesive layer has a storage elastic modulus at 23 ° C. of 0.2 to 10 MPa and a thickness of 2 μm to 25 μm. It has been proposed to use less than one (Patent Document 1). In addition, in order to provide good durability even in a high-temperature environment, a pressure-sensitive adhesive layer is provided on one side of the polarizer, and a protective layer made of a transparent resin film is provided on the other side of the polarizer. It has been proposed that a pressure-sensitive adhesive layer having a storage modulus of 0.15 to 1 MPa in a temperature range of 23 to 80 ° C. be used in a plate (Patent Document 2). Further, in order to suppress the occurrence of the through cracks, as the pressure-sensitive adhesive layer of the piece-protected polarizing film with a pressure-sensitive adhesive layer, the contraction force in the direction orthogonal to the absorption axis of the polarizer is controlled to be small, and the pressure-sensitive adhesive layer has It has been proposed to use a material having a storage elastic modulus at 23 ° C. of 0.20 MPa or more (Patent Document 3). Further, thinning has also been performed on polarizers. For example, a thin polarizer that exhibits high orientation and has controlled optical characteristics such as single transmittance and degree of polarization has been proposed (Patent Document 4).

However, in Patent Document 1, even if the durability is satisfied, the thickness of the polarizer is as large as 25 μm, so that the generation of through cracks due to the contraction stress of the polarizer cannot be prevented. Further, in Patent Documents 1 to 3, since the object is to improve the durability of the piece protective polarizing film provided with the pressure-sensitive adhesive layer, boric acid used for the polarizer is relatively large. If the amount of boric acid contained in the polarizer is larger than a specific value, crosslinking by boric acid is promoted during heating and the shrinkage stress of the polarizer increases, which is not preferable from the viewpoint of suppressing the occurrence of through cracks. I understood that. That is, in Patent Documents 1 to 3, although the through crack can be prevented to some extent by controlling the storage elastic modulus of the pressure-sensitive adhesive layer, it cannot be said that the occurrence of the through crack can be sufficiently suppressed.

On the other hand, thinning is also being done on polarizers. When the polarizer used for the piece-protecting polarizing film with an adhesive layer is made thinner, the change in the shrinkage stress of the polarizer becomes smaller. Therefore, it was found that the use of a thinner polarizer can suppress the occurrence of the through crack.

However, in the piece protective polarizing film with the pressure-sensitive adhesive layer in which the occurrence of the through crack is suppressed, the optical characteristics are controlled and the polarizer is thinned (for example, the thickness is set to 12 μm or less) as in Patent Document 4. When a mechanical shock is applied to the piece-protecting polarizing film with an adhesive layer (including a case where a load is applied to the polarizer side due to a convex fold), a very fine slit (partially in the absorption axis direction of the polarizer) Hereinafter, this is also referred to as a nanoslit). It has also been found that the nanoslits occur independently of the size of the polarizing film. Furthermore, it was also found that the nanoslit did not occur when both protective polarizing films having protective films on both surfaces of the polarizer were used. In addition, when a through crack occurs in the polarizer, the stress around the through crack is released, so the through crack does not occur adjacently, but the nanoslit occurs independently and is adjacent to the crack. It was found to occur. In addition, it was also found that the through crack had a progression extending in the absorption axis direction of the cracked polarizer, but the nanoslit did not have the progression. As described above, the nano-slit is a new problem that occurs when the polarizer is thin and the optical characteristics are controlled within a predetermined range in the one-sided protective polarizing film in which the generation of a through crack is suppressed. It has been found that this is a problem caused by a phenomenon different from the above-described through crack.

In addition, since the nanoslit is extremely fine, it cannot be detected in a normal environment. Therefore, even if nano-slits are generated in the polarizer, it is difficult at first glance to confirm a defect due to light leakage of the piece-protecting polarizing film with the adhesive layer. That is, usually, the one-sided protective polarizing film is manufactured in a long film shape and is automatically inspected for defects by an optical inspection. However, it is difficult to detect a nano slit as a defect in the defect inspection. The defect caused by the nanoslit can be detected by spreading the nanoslit in the width direction when the piece protective polarizing film with the adhesive layer is attached to a glass substrate or the like of an image display panel and then placed in a heating environment. (For example, the presence or absence of the light leakage).

Therefore, in a piece-protecting polarizing film with a pressure-sensitive adhesive layer using a thin polarizer, it is desired to suppress not only cracks through, but also defects due to nanoslits. Further, in the case of a piece-protected polarizing film with an adhesive layer, the polarizing film is easily broken or broken during handling because it is thinner than a polarizing film having a protective film on both sides and having a double protection structure.

技術 In order to suppress the defects caused by the nanoslits, a technique has been proposed in which a transparent layer (coating layer) is provided between a polarizer and a pressure-sensitive adhesive layer of a piece-protecting polarizing film with a pressure-sensitive adhesive layer (Patent Document 5). The provision of the transparent layer makes it difficult for the polarizing film to bend when an external stress is applied to the polarizing film, so that the occurrence of nano slits can be suppressed.

In addition, when manufacturing the liquid crystal display device, when the protective film with adhesive layer is adhered to the liquid crystal cell, the release film is peeled from the adhesive layer of the protective film with adhesive layer. Static electricity is generated by peeling the mold film. The static electricity generated in this way affects the orientation of the liquid crystal inside the liquid crystal display device, and causes a defect. In addition, display unevenness may occur due to static electricity when the liquid crystal display device is used. The generation of static electricity can be suppressed, for example, by forming an antistatic layer on the outer surface of the polarizing film. However, the effect is small and there is a problem that the generation of static electricity cannot be fundamentally prevented. Therefore, in order to suppress the generation of static electricity at a fundamental position, it is required to provide the pressure-sensitive adhesive layer with an antistatic function. As means for imparting an antistatic function to the pressure-sensitive adhesive layer, for example, it has been proposed to mix an ionic compound with the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer (Patent Documents 6 to 8). Specifically, Patent Document 6 proposes a pressure-sensitive adhesive composition for an optical film, which contains an alkali metal salt and / or an organic cation-anion salt. Patent Document 7 proposes a pressure-sensitive adhesive composition containing an onium-anion salt and an alkali metal salt as a raw material of a pressure-sensitive adhesive layer of a polarizing film with a pressure-sensitive adhesive layer. Patent Document 8 proposes a pressure-sensitive adhesive composition containing an alkali metal salt as a raw material for a pressure-sensitive adhesive layer of a pressure-sensitive adhesive polarizing plate.

Further, the pressure-sensitive adhesive layer of the piece-protecting polarizing film with a pressure-sensitive adhesive layer is required to have high durability. For example, in a durability test such as heating and humidification usually performed as an environmental promotion test, peeling or floating caused by the pressure-sensitive adhesive layer is required. It is required that such troubles do not occur.

Various pressure-sensitive adhesive compositions for such optical applications have been studied, and for example, a pressure-sensitive adhesive composition that does not cause peeling or foaming even when placed under high humidity and heat conditions after adhering an optical film is proposed. (Patent Document 9).

JP 2010-44211 A JP 2008-197309 A JP 2013-72951 A Patent No. 4,751,481 Japanese Patent No. 6077618 JP-A-2005-199942 JP-A-2014-48497 JP 2012-247574 A JP 2009-242767 A

However, when a glass substrate with a polarizing film, in which a conventional protective film with a pressure-sensitive adhesive layer is bonded to a glass substrate or the like forming a liquid crystal panel surface, is placed in an environment where dew condensation occurs, the glass substrate and the adhesive layer may There is a problem that peeling easily occurs at the interface.

In addition, when sticking a piece-protecting polarizing film with an adhesive layer to a glass substrate or the like forming a liquid crystal panel surface, when a foreign substance or a bubble is mixed and a bonding error occurs, the polarizing film is attached to a glass substrate or the like. Need to be peeled off. A piece protective polarizing film with a pressure-sensitive adhesive layer using a thin polarizer has a very thin overall thickness because the polarizer is thin and the protective film is provided only on one side of the polarizer. Therefore, there is a problem that the conventional piece-protected polarizing film with a pressure-sensitive adhesive layer using a thin polarizer is easily broken when peeled from a glass substrate or the like. For this reason, the pressure-sensitive adhesive layer is also required to have a reworking property that does not cause a problem when the polarizing film is peeled off from a glass substrate or the like.

The present invention is an adhesive which has excellent initial reworkability, durability in a high-temperature and / or high-humidity environment, and conductive stability, and is hard to peel off from a glass substrate or the like even when exposed to an environment where dew condensation occurs. An object of the present invention is to provide a piece-protected polarizing film with a layer. Further, in addition to the above-mentioned effects, an object is to provide a piece-protected polarizing film with an adhesive layer that can suppress defects due to nanoslits without providing a coating layer between the polarizer and the adhesive layer. I do.

Another object of the present invention is to provide an image display device having the piece-protecting polarizing film provided with the pressure-sensitive adhesive layer, and a continuous production method thereof.

発明 As a result of intensive studies, the inventors of the present application have found that the above problem can be solved by the following piece-protected polarizing film with an adhesive layer and the like, and have accomplished the present invention.

That is, the present invention provides a one-sided protective polarizing film having a protective film only on one surface of a polarizer and a one-sided protective polarizing plate with an adhesive layer having an adhesive layer directly or via a coating layer on the polarizer side of the one-sided protective polarizing film. A film,
The pressure-sensitive adhesive layer contains a (meth) acrylic polymer as a base polymer,
The pressure-sensitive adhesive layer has a weight change rate calculated by the following formula (1) of 1.1% or more,
The pressure-sensitive adhesive layer has a pressure-sensitive adhesive force P ₀ of 10 N / 25 mm or less under the following conditions, and a pressure-sensitive adhesive force P ₁ of 1.6 N / 25 mm or more under the following conditions. Film.

Weight change rate (%) = {(W ₁ −W ₀ ) / W ₀ } × 100 (1)
W ₀ = weight of the pressure-sensitive adhesive layer after drying the pressure-sensitive adhesive layer at 23 ° C. for 2 hours W ₁ = standing of the pressure-sensitive adhesive layer after the drying at 23 ° C. and 55% RH for 5 hours, and further at 60 ° C. 95% Weight of adhesive layer after leaving at RH for 5 hours
Adhesive force P ₀ : The pressure-sensitive adhesive layer of the piece-protected polarizing film with the pressure-sensitive adhesive layer was stuck on the surface of an alkali-free glass, and subjected to an autoclave treatment at 50 ° C. and 0.5 atm for 15 minutes. Adhesive force when peeling the pressure-sensitive adhesive layer from the surface of the alkali-free glass under the conditions of a peeling speed of 300 mm / min and a peeling angle of 90 degrees. Adhesive force P ₁ : No adhesive layer of the above-mentioned piece-protected polarizing film with an adhesive layer. A laminate obtained by attaching the laminate to the surface of an alkali glass and then performing an autoclave treatment at 50 ° C. and 0.5 atm for 15 minutes is immersed in water at 23 ° C. for 2 hours. Adhesive force when the pressure-sensitive adhesive layer is peeled off from the alkali-free glass surface under the conditions of a temperature of 23 ° C., a peeling speed of 300 mm / min, and a peeling angle of 90 °.

In order to impart durability and conductive stability to the pressure-sensitive adhesive layer provided on the polarizer side of the one-sided protective polarizing film, a polar monomer is introduced by copolymerization into a (meth) acrylic polymer as a base polymer of the pressure-sensitive adhesive layer. Is preferred. However, a (meth) acrylic polymer in which a polar monomer is introduced by copolymerization has a high hydrophilicity. Therefore, it is considered that the pressure-sensitive adhesive layer containing the (meth) acrylic polymer easily absorbs water when exposed to an environment in which dew condensation occurs, and is likely to be easily peeled off from a glass substrate or the like because the adhesive strength is easily reduced. The present inventors have conducted extensive studies on the physical properties of the pressure-sensitive adhesive layer provided on the polarizer side of the one-sided protective polarizing film, the initial reworkability, and the relationship between peeling from the glass substrate and the like. By adjusting the rate of change in weight before and after humidification and the adhesive force under specific conditions to specific ranges, it is possible to maintain high initial reworkability, durability under high temperature and / or high humidity environments, and high conductive stability. It has been found that a piece-protected polarizing film with an adhesive layer that is hard to peel off from a glass substrate or the like even when exposed to an environment in which dew condensation occurs can be obtained.

The (meth) acrylic polymer, as a monomer unit,
Alkyl (meth) acrylate (A) having a homopolymer having a glass transition temperature of less than 0 ° C. is 50% by weight or more, and alkyl (meth) acrylate (b1) and a homopolymer having a homopolymer having a glass transition temperature of 0 ° C. or more Having a glass transition temperature of 0 ° C. or higher and at least one high Tg monomer (B) selected from the group consisting of (meth) acryloyl group-containing monomers (b2) having a heterocyclic ring in an amount of 0.1 to 20% by weight. %.

The (meth) acrylic polymer is at least one selected from the group consisting of a nitrogen-containing monomer, a carboxyl group-containing monomer, a hydroxyl group-containing monomer, and an aromatic group-containing monomer as the monomer unit, It is preferable to contain a polar monomer other than the (meth) acryloyl group-containing monomer (b2).

The nitrogen-containing monomer is preferably a vinyl monomer having a lactam ring. Further, the vinyl-based monomer having a lactam ring is preferably a vinylpyrrolidone-based monomer. Further, the vinylpyrrolidone-based monomer is preferably N-vinylpyrrolidone.

Further, the (meth) acrylic polymer preferably contains 0.1 to 5% by weight of the nitrogen-containing monomer and 0.01 to 3% by weight of the carboxyl group-containing monomer as a monomer unit. Preferably, the hydroxyl group-containing monomer is contained in an amount of 0.01 to 1% by weight, and the aromatic group-containing monomer is preferably contained in an amount of 1 to 20% by weight.

（The (meth) acrylic polymer preferably has a weight average molecular weight of 1.5 million or less.

The pressure-sensitive adhesive layer preferably contains a silane coupling agent having at least one functional group selected from the group consisting of an epoxy group, an isocyanate group, a mercapto group, an acid anhydride group, and an amino group. The content of the silane coupling agent is preferably 0.01 to 3 parts by weight based on 100 parts by weight of the (meth) acrylic polymer.

The polarizer preferably has a thickness of 12 µm or less.

The polarizer contains a polyvinyl alcohol-based resin, and has an optical property represented by a single transmittance T and a degree of polarization P of the following formula: P>-(10 ^0.929T-42.4 -1) × 100 (however, T <42.3) or
It is preferable that the configuration is such that the condition of P ≧ 99.9 (where T ≧ 42.3) is satisfied.

The polarizer preferably contains boric acid in an amount of 25% by weight or less based on the total amount of the polarizer.

セパレータ A separator can be provided on the pressure-sensitive adhesive layer of the piece-protecting polarizing film with the pressure-sensitive adhesive layer. The piece-protected polarizing film with the pressure-sensitive adhesive layer provided with the separator can be used as a roll.

(4) The present invention also relates to an image display device having the piece-protecting polarizing film provided with the pressure-sensitive adhesive layer.

Further, the present invention provides an image display panel, wherein the piece protective polarizing film with an adhesive layer is unwound from the wound body of the piece of protective polarizing film with an adhesive layer and is conveyed by the separator, via the adhesive layer. And a method for continuously manufacturing an image display device including a step of continuously bonding the image display device to a surface of the image display device.

The piece protective polarizing film with the pressure-sensitive adhesive layer of the present invention is excellent in initial reworkability. Therefore, even when a thin polarizer is used, the polarizing film can be peeled off from a glass substrate or the like without breaking. . In addition, since the piece-protecting polarizing film with an adhesive layer of the present invention has excellent durability in a high-temperature and / or high-humidity environment, problems such as peeling and floating caused by the adhesive layer hardly occur. In addition, since the piece-protecting polarizing film with the pressure-sensitive adhesive layer of the present invention has excellent conductivity stability in a humid environment, the polarizer is hardly deteriorated, and the polarizer hardly loses color. Further, the piece-protecting polarizing film provided with the pressure-sensitive adhesive layer of the present invention has a low adhesive strength even when exposed to an environment in which dew condensation occurs, and is hardly peeled off from a glass substrate or the like. Furthermore, since the piece-protecting polarizing film with the pressure-sensitive adhesive layer of the present invention has the pressure-sensitive adhesive layer, the generation of nanoslits can be effectively suppressed without providing a coating layer.

It is an example of a schematic sectional view of the piece protection polarizing film with an adhesive layer of the present invention. It is an example of a conceptual diagram which contrasts a nano slit and a penetration crack which occur in a polarizer. It is the schematic explaining the evaluation item regarding the nano slit of an Example and a comparative example. It is an example of the photograph which shows the crack which arises by the nanoslit concerning the evaluation of an Example and a comparative example. It is an example of a schematic sectional view of a continuous manufacturing system of an image display device.

片 Hereinafter, the piece-protecting polarizing film provided with the pressure-sensitive adhesive layer of the present invention will be described with reference to FIG. The piece-protected polarizing film 11 with an adhesive layer of the present invention has, for example, a piece-protected polarizing film 10 and an adhesive layer 4. The pressure-sensitive adhesive layer 4 is a pressure-sensitive adhesive layer according to the present invention. As shown in FIG. 1, the one-side protective polarizing film 10 has the protective film 2 on only one side of the polarizer 1. The polarizer 1 and the protective film 2 are laminated via an adhesive layer 3 (an intervening layer such as an adhesive layer and an undercoat layer (primer layer)). Although not shown, the one-sided protective polarizing film 10 can be provided with an easy-adhesion layer on the protective film 2 or subjected to an activation treatment, so that the easy-adhesion layer and the adhesive layer can be laminated. Although not shown, a plurality of protective films 2 can be provided. The plurality of protective films 2 can be laminated by an adhesive layer 3 (an intervening layer such as an adhesive layer and an undercoat layer (primer layer)).

As shown in FIG. 1, the pressure-sensitive adhesive layer 4 of the piece-protected polarizing film 11 with a pressure-sensitive adhesive layer of the present invention is provided on the side of the polarizer 1 of the piece-protected polarizing film 10. Although not shown, a coating layer may be provided between the polarizer 1 and the pressure-sensitive adhesive layer 4. The coating layer is not particularly limited, and for example, a known transparent layer described in Japanese Patent No. 6077618 or the like can be used. In addition, the separator 5 can be provided in the adhesive layer 4 of the piece protective polarizing film with an adhesive layer 11 of the present invention, and the surface protective film 6 can be provided on the opposite side. In the piece protective polarizing film 11 with an adhesive layer of FIG. 1, the case where both the separator 5 and the surface protective film 6 are provided is shown. The piece protective polarizing film 11 with an adhesive layer having at least the separator 5 (and further having the surface protective film 6) can be used as a wound body, for example, as described later, is unwound from the wound body, A method (hereinafter, also referred to as a “roll-to-panel method”) in which the piece-protecting polarizing film with an adhesive layer 11 conveyed by the separator 5 is bonded to the surface of the image display panel via the adhesive layer 4. Is advantageous for application to Japanese Patent No. 4406043). The piece-protecting polarizing film provided with the pressure-sensitive adhesive layer shown in FIG. 1 is preferably used from the viewpoint of suppressing the warpage of the display panel after lamination, suppressing the occurrence of nanoslits, and the like.

FIG. 2 is a conceptual diagram comparing a nano slit a and a through crack b generated in a polarizer. FIG. 2A shows a nanoslit a generated in the polarizer 1, and FIG. 2B shows a through crack b generated in the polarizer 1. The nanoslit a is generated due to mechanical shock and is partially generated in the absorption axis direction of the polarizer 1. The nanoslit a cannot be confirmed at first when it is generated, but under a thermal environment (for example, 80 ° C., 60 ° C., (90% RH), it can be confirmed by the spread in the width direction. On the other hand, it is considered that the nanoslit a does not have a progressive property extending in the absorption axis direction of the polarizer. Further, it is considered that the nano-slits a occur regardless of the size of the polarizing film. The nanoslits a may occur independently or may be adjacent to each other. On the other hand, the through crack b is generated by a thermal shock (for example, a heat shock test). The penetrating crack has a progression that extends in the absorption axis direction of the polarizer in which the crack has occurred. When the through crack b occurs, the peripheral stress is released, and the through crack does not occur adjacently.

<Polarizer>
In the present invention, the thickness of the polarizer is preferably 12 μm or less, more preferably 10 μm or less, further preferably 8 μm or less, further more preferably 7 μm or less, particularly from the viewpoint of reducing the thickness and suppressing the occurrence of through 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 unevenness, is excellent in visibility, and has little dimensional change, and thus has excellent durability against thermal shock.

A polarizer using a polyvinyl alcohol-based resin is used. Examples of the polarizer include, for example, a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, a hydrophilic polymer film such as an ethylene-vinyl acetate copolymer-based partially saponified film, and dichroic properties of iodine and a dichroic dye. Examples thereof include a uniaxially stretched film obtained by adsorbing a substance, and a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol and a dehydrochlorinated product of polyvinyl chloride. Among these, a polarizer composed of a polyvinyl alcohol-based film and a dichroic substance such as iodine is preferable.

(4) A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching can be produced by, for example, dyeing polyvinyl alcohol by immersing it in an aqueous solution of iodine, and stretching the film to 3 to 7 times its original length. If necessary, it may contain boric acid, zinc sulfate, zinc chloride, or the like, or may be immersed in an aqueous solution of potassium iodide or the like. Further, if necessary, the polyvinyl alcohol-based film may be immersed in water and washed with water before dyeing. By washing the polyvinyl alcohol-based film with water, dirt on the surface of the polyvinyl alcohol-based film and an anti-blocking agent can be washed, and by swelling the polyvinyl alcohol-based film, the effect of preventing unevenness such as uneven dyeing can be obtained. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be stretched and then dyed with iodine. Stretching can be performed in an aqueous solution of boric acid or potassium iodide or in a water bath.

The polarizer preferably contains boric acid from the viewpoint of stretching stability and optical durability. Further, the content of boric acid contained in the polarizer is preferably 25% by weight or less, more preferably 20% by weight or less with respect to the total amount of the polarizer, from the viewpoint of suppressing the generation of penetration cracks and nanoslits and suppressing expansion. It is preferably 18% by weight or less, more preferably 16% by weight or less. When the content of boric acid in the polarizer exceeds 25% by weight, even when the thickness of the polarizer is small (for example, 12 μm or less), the shrinkage stress of the polarizer is increased, and a through crack is easily generated. Is not preferred. On the other hand, from the viewpoint of the stretching stability and the optical durability of the polarizer, the boric acid content based on the total amount of the polarizer is preferably 10% by weight or more, and more preferably 12% by weight or more.

As a thin polarizer, typically,
Patent No. 4751486,
Patent No. 4,751,481,
Patent No. 4815544,
Patent No. 5048120,
Patent No. 5,587,517,
WO 2014/077599 pamphlet,
WO 2014/077636 pamphlet,
And the like, or a thin polarizer obtained from the production method described therein.

The polarizer has an optical property represented by a single transmittance T and a degree of polarization P of the following formula: P>-(10 ^0.929T-42.4 -1) × 100 (where T <42.3); Or
It is preferable that the configuration is such that the condition of P ≧ 99.9 (where T ≧ 42.3) is satisfied. A polarizer configured to satisfy the above conditions has the performance required as a display for a liquid crystal television using a large-sized display element. Specifically, the contrast ratio is 1000: 1 or more and the maximum luminance is 500 cd / m ² or more. As another application, for example, it is bonded to the viewing side of the organic EL display device.

On the other hand, a polarizer configured to satisfy the above conditions has a high orientation of a constituent polymer (for example, a polyvinyl alcohol-based molecule), and thus is combined with being thin (for example, having a thickness of 12 μm or less). In addition, the tensile rupture stress in the direction orthogonal to the absorption axis direction of the polarizer is significantly reduced. As a result, for example, when the polarizing film is exposed to mechanical shock exceeding the tensile rupture stress in the manufacturing process, there is a very high possibility that a nanoslit is formed in the absorption axis direction of the polarizer. Therefore, the present invention is particularly suitable for a piece-protected polarizing film employing the polarizer (or a piece-protected polarizing film with an adhesive layer using the same).

Among the thin polarizers, among the production methods including a step of stretching in a state of a laminate and a step of dyeing, Patent No. 4751486, which can be stretched at a high magnification to improve polarization performance, Preferred are those obtained by a production method including a step of stretching in a boric acid aqueous solution as described in JP-B-47515481 and JP-B-4815544, and particularly described in JP-B-4775481 and JP-B-4815544. What is obtained by the manufacturing method including the process of auxiliary | assistant air-stretching before extending | stretching in a boric-acid aqueous solution with a certain thing is preferable. These thin polarizers can be obtained by a manufacturing method including a step of stretching a polyvinyl alcohol-based resin (hereinafter also referred to as a PVA-based resin) layer and a stretching resin base material in the state of a laminate, and a step of dyeing. According to this production method, even if the PVA-based resin layer is thin, it can be stretched without any trouble such as breakage due to stretching, because it is supported by the stretching resin base material.

<Protective film>
As a material constituting the protective film, a material having excellent transparency, mechanical strength, heat stability, moisture barrier property, isotropy, and the like is preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulosic polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, and styrene such as polystyrene and acrylonitrile-styrene copolymer (AS resin) Polymers, polycarbonate polymers and the like. In addition, polyethylene, polypropylene, polyolefin having a cyclo- or norbornene structure, polyolefin polymers such as ethylene-propylene copolymer, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, and sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Blends of polymers and the like are also examples of the polymer forming the protective film.

The protective film may contain one or more optional additives. Examples of the additives include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a coloring inhibitor, a flame retardant, a nucleating agent, an antistatic agent, a pigment, and a coloring agent. The content of the thermoplastic resin in the protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, further preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. When the content of the thermoplastic resin in the protective film is 50% by weight or less, high transparency or the like inherent to the thermoplastic resin may not be sufficiently exhibited.

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

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

(4) The thickness of the protective film can be determined as appropriate, but is generally about 1 to 500 μm from the viewpoint of workability such as strength and handleability and thinness. It is particularly preferably from 1 to 300 μm, more preferably from 5 to 200 μm, furthermore preferably from 5 to 150 μm, particularly preferably from 5 to 80 μm.

機能 A functional layer such as a hard coat layer, an anti-reflection layer, an anti-sticking layer, a diffusion layer or an anti-glare layer can be provided on the surface of the protective film on which the polarizer is not adhered. The functional layers such as the hard coat layer, the antireflection layer, the anti-sticking layer, the diffusion layer and the antiglare layer can be provided on the protective film itself, or separately provided separately from the protective film. it can.

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

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

Examples of the water-based adhesive include an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl latex-based adhesive, and an aqueous polyester. 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.

The active energy ray-curable adhesive is an adhesive whose curing progresses with an active energy ray such as an electron beam or an ultraviolet ray (radical-curable or cationically-curable). Can be used. As the active energy ray-curable adhesive, for example, a photo-radical curable adhesive can be used. When a photo-radical curable active energy ray-curable adhesive is used as an ultraviolet curable adhesive, the adhesive contains a radical polymerizable compound and a photopolymerization initiator.

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

In addition, when using an aqueous adhesive or the like, the adhesive is preferably applied so that the thickness of the finally formed adhesive layer is 30 to 300 nm. The thickness of the adhesive layer is more preferably 60 to 250 nm. On the other hand, when an active energy ray-curable adhesive is used, the thickness of the adhesive layer is preferably set to 0.1 to 200 μm. More preferably, it is 0.5 to 50 μm, further preferably 0.5 to 10 μm.

積層 When laminating the polarizer and the protective film, an easy-adhesion layer can be provided between the protective film and the adhesive layer. The easy-adhesion layer can be formed of, for example, various resins having a polyester skeleton, polyether skeleton, polycarbonate skeleton, polyurethane skeleton, silicone, polyamide skeleton, polyimide skeleton, polyvinyl alcohol skeleton, and the like. These polymer resins can be used alone or in combination of two or more. Further, other additives may be added to the formation of the easily adhesive layer. Specifically, stabilizers such as tackifiers, ultraviolet absorbers, antioxidants, and heat stabilizers may be used.

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

The pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive. Various pressure-sensitive adhesives can be used as the pressure-sensitive adhesive. An acrylamide-based pressure-sensitive adhesive, a cellulose-based pressure-sensitive adhesive, and the like can be given. An adhesive base polymer is selected according to the type of the adhesive. Among the above-mentioned pressure-sensitive adhesives, acrylic pressure-sensitive adhesives are preferably used because they are excellent in optical transparency, exhibit appropriate wettability, cohesiveness and adhesive pressure-sensitive adhesive properties, and are excellent in weather resistance and heat resistance. You.

The undercoat layer (primer layer) is formed to improve the adhesion between the polarizer and the protective film. The material constituting the primer layer is not particularly limited as long as it exhibits 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, stretchability and the like is used. Examples of the thermoplastic resin include an acrylic resin, a polyolefin resin, a polyester resin, a polyvinyl alcohol resin, and a mixture thereof.

<Adhesive layer>
The pressure-sensitive adhesive layer of the protective film with pressure-sensitive adhesive layer of the present invention is formed of an acrylic pressure-sensitive adhesive containing a (meth) acryl-based polymer as a base polymer. Acrylic pressure-sensitive adhesives are excellent in optical transparency, exhibit appropriate wettability, cohesiveness and adhesive pressure-sensitive adhesive properties, and are excellent in weather resistance, heat resistance, and the like, and are therefore suitable as a material for forming a pressure-sensitive adhesive layer. .

The pressure-sensitive adhesive layer has a weight change rate calculated by the following formula (1) of 1.1% or more, preferably 1.2% or more, and more preferably 1.3% or more. When the weight change rate is less than 1.1%, durability and conductive stability of the pressure-sensitive adhesive layer in a high-temperature and / or high-humidity environment tend to deteriorate. From the viewpoint of adjusting the following adhesion P ₁ and P ₂ in the desired range, it is preferable that the weight change rate is 2.0% or less, and more preferably not more than 1.8%.
Weight change rate (%) = {(W ₁ −W ₀ ) / W ₀ } × 100 (1)
W ₀ = weight of the pressure-sensitive adhesive layer after drying the pressure-sensitive adhesive layer at 23 ° C. for 2 hours W ₁ = standing of the pressure-sensitive adhesive layer after the drying at 23 ° C. and 55% RH for 5 hours, and further at 60 ° C. 95% Weight of adhesive layer after leaving at RH for 5 hours

Further, the pressure-sensitive adhesive layer is adhesion strength _{P 0} is 10 N / 25 mm or less in the following conditions, and it is adhesive strength _{P 1} at the following conditions is 1.6 N / 25 mm or more. The adhesive strength _{P 0} is more than 10 N / 25 mm, the initial re-workability is deteriorated. From the point of view, the adhesive strength _{P 0} is preferably at most 8N / 25 mm, more preferably not more than 6N / 25 mm. Also, the when the adhesive force P ₁ is less than 1.6 N / 25 mm, the condensation adhesive strength tends to decrease when is exposed to an environment that occurs, the adhesive layer is easily peeled off from the glass substrate. From the point of view, the adhesive force _{P 1} is preferably at 2N / 25 mm or more, more preferably 3N / 25 mm or more.
Adhesive force P ₀ : The pressure-sensitive adhesive layer of the piece-protected polarizing film with the pressure-sensitive adhesive layer was stuck on the surface of an alkali-free glass, and subjected to an autoclave treatment at 50 ° C. and 0.5 atm for 15 minutes. Adhesive force when peeling the pressure-sensitive adhesive layer from the surface of the alkali-free glass under the conditions of a peeling speed of 300 mm / min and a peeling angle of 90 degrees. Adhesive force P ₁ : No adhesive layer of the above-mentioned piece-protected polarizing film with an adhesive layer. A laminate obtained by attaching the laminate to the surface of an alkali glass and then performing an autoclave treatment at 50 ° C. and 0.5 atm for 15 minutes is immersed in water at 23 ° C. for 2 hours. Adhesive force when the pressure-sensitive adhesive layer is peeled off from the alkali-free glass surface under the conditions of a temperature of 23 ° C., a peeling speed of 300 mm / min, and a peeling angle of 90 °.

Further, the pressure-sensitive adhesive layer, from the viewpoint, it is preferable that the adhesive force _{P 2} in the following conditions is 0.8N / 25 mm or more, more preferably 1.0 N / 25 mm or more.
Adhesive force P ₂ : The adhesive layer of the piece protective polarizing film with an adhesive layer was stuck on the surface of an alkali-free glass, and then autoclaved at 50 ° C. and 0.5 atm for 15 minutes to obtain a laminate of 23. After immersing the laminate in water at 5 ° C. for 5 hours and removing the laminate from the water, the pressure-sensitive adhesive layer was peeled off from the surface of the alkali-free glass at a peeling temperature of 23 ° C., a peeling speed of 300 mm / min, and a peeling angle of 90 °. Adhesion at time

As the (meth) acrylic polymer, those having a main unit of an alkyl (meth) acrylate monomer unit can be used. In addition, (meth) acrylate means acrylate and / or methacrylate, and has the same meaning as (meth) in the present invention.

The alkyl group of the alkyl (meth) acrylate constituting the main skeleton of the (meth) acrylic polymer has about 1 to 18 carbon atoms. Specific examples of the alkyl (meth) acrylate include methyl (meth) acrylate and ethyl. (Meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate , Octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, etc. Can, it may be used alone or in combination.

In order to obtain a pressure-sensitive adhesive layer having the weight change rate and the pressure-sensitive adhesive force P ₀ to P ₂ and further suppressing the generation of nanoslits, the (meth) acryl-based polymer is a homopolymer glass as a monomer unit. Alkyl (meth) acrylate (A) having a transition temperature of less than 0 ° C (more preferably -20 ° C or less, more preferably -40 ° C or less) is 50% by weight or more (more preferably 60% by weight or more, further more preferably Alkyl (meth) acrylate (b1) having a glass transition temperature of 70% by weight or more, more preferably 80% by weight or more, and a homopolymer having a glass transition temperature of 0 ° C. or more (more preferably 20 ° C. or more, still more preferably 40 ° C. or more) ) And the homopolymer have a glass transition temperature of 0 ° C or higher (more preferably 20 ° C or higher, still more preferably 40 ° C or higher); 0.1 to 20% by weight (more preferably 1 to 15% by weight, more preferably 1 to 15% by weight) of at least one high Tg monomer (B) selected from the group consisting of (meth) acryloyl group-containing monomers (b2) having a ring. Is preferably 2.5 to 10% by weight, more preferably 4% to less than 10% by weight. In the case where the alkyl (meth) acrylate (b1) and the (meth) acryloyl group-containing monomer (b2) are used in combination, the total is% by weight.

Examples of the alkyl (meth) acrylate (A) include ethyl acrylate (Tg: −24 ° C.), n-butyl acrylate (Tg: −50 ° C.), 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), i-propyl acrylate ( Tg: -3 ° C), i-butyl acrylate (Tg: -40 ° C), i-octyl acrylate (Tg: -58 ° C) i- octyl methacrylate (Tg: -45 ℃), 2- ethylhexyl acrylate (Tg: -70 ℃), 2- ethylhexyl methacrylate: include (Tg -10 ° C.) and the like. These can be used alone or in combination. Among these, it is preferable to use at least one selected from ethyl acrylate, n-butyl acrylate, n-pentyl methacrylate, n-hexyl acrylate, and 2-ethylhexyl acrylate, and it is more preferable to use n-butyl acrylate . The Tg (glass transition temperature) in each parenthesis is the Tg of a 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.), and n-propyl acrylate (Tg: 3 ° C.). ), N-propyl methacrylate (Tg: 35 ° C.), n-pentyl acrylate (Tg: 22 ° C.), n-tetradecyl acrylate (Tg: 24 ° C.), n-hexadecyl acrylate (Tg: 35 ° C.), n- Linear alkyl (meth) acrylates such as hexadecyl methacrylate (Tg: 15 ° C), n-stearyl acrylate (Tg: 30 ° C), and n-stearyl methacrylate (Tg: 38 ° C); t-butyl acrylate (Tg: 43) ° C), t-butyl methacrylate (Tg: 48 ° C), i-propylmethacrylate Branched alkyl (meth) acrylates such as acrylate (Tg: 81 ° C.) and i-butyl methacrylate (Tg: 48 ° C.); cyclohexyl acrylate (Tg: 19 ° C.), cyclohexyl methacrylate (Tg: 65 ° C.), isobornyl Acrylate (Tg: 94 ° C.); and cyclic alkyl (meth) acrylate such as isobornyl methacrylate (Tg: 180 ° C.). These can be used alone or in combination. Among these, it is preferable to use at least one selected from methyl acrylate, methyl methacrylate, ethyl methacrylate, isobornyl acrylate, and isobornyl methacrylate, and is preferably selected from methyl acrylate, methyl methacrylate, and isobornyl acrylate. More preferably, at least one kind is used.

The (meth) acryloyl group-containing monomer (b2) has a heterocyclic ring. Heterocycle is not particularly limited, for example, aziridine ring, azetidine ring, pyrrolidine ring, piperidine ring, piperazine ring, and heteroaliphatic ring such as morpholine ring, pyrrole ring, imidazole ring, pyrazole ring, oxazole ring, isoxazole ring , A thiazole ring, an isothiazole ring, a pyridine ring, a pyrimidine ring, a pyridazine ring, and a heteroaromatic ring such as a pyrazine ring. The heterocyclic ring may be directly bonded to the (meth) acryloyl group, or may be bonded to the (meth) acryloyl group via a connecting group. Of these, a heteroaliphatic ring is preferred, and a morpholine ring is more preferred. Examples of the (meth) acryloyl group-containing monomer (b2) include N-acryloyl morpholine (Tg: 145 ° C.). These can be used alone or in combination. Among these, it is particularly preferable to use N-acryloylmorpholine.

、１ One or more various monomers can be introduced into the (meth) acrylic polymer by copolymerization for the purpose of improving adhesiveness and heat resistance. Specific examples of such a copolymerized monomer (excluding the (meth) acryloyl group-containing monomer (b2)) include a carboxyl group-containing monomer, a hydroxyl group-containing monomer, a nitrogen-containing monomer, and an aromatic group-containing monomer. No.

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 can be used alone or in combination.

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

Examples of the nitrogen-containing monomer include vinyl monomers having a lactam ring (eg, vinylpyrrolidone monomers such as N-vinylpyrrolidone and methylvinylpyrrolidone, and β-lactam ring, δ-lactam ring, and ε-lactam ring, etc. Vinyl lactam monomers having a lactam ring); maleimide monomers such as maleimide, N-cyclohexylmaleimide, 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) acrylamide, N-methylol (meth) acrylamide, N-methylolpropane (Meta (N-substituted) amide monomers such as acrylamide; aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, t-butylamino (meth) acrylate Aminoalkyl (meth) acrylate monomers such as ethyl and 3- (3-pyridinyl) propyl (meth) acrylate; N- (meth) acryloyloxymethylene succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide; Succinimide monomers such as N- (meth) acryloyl-8-oxyoctamethylene succinimide; cyano (meth) acrylate monomers such as acrylonitrile and methacrylonitrile; vinylpyridine, vinylpiperidone, vinylpyrimidine and vinylpipe Jin, vinyl pyrazine, vinyl pyrrole, vinyl imidazole, vinyl oxazole, vinyl morpholine, and the like N- vinylcarboxylic acid amides. These can be used alone or in combination.

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

In addition to the above monomers, monomers having an acid anhydride group such as maleic anhydride and itaconic anhydride; caprolactone adduct of acrylic acid; styrenesulfonic acid, allylsulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid And sulfonic acid group-containing monomers such as (meth) acrylamidopropanesulfonic acid, sulfopropyl (meth) acrylate and (meth) acryloyloxynaphthalenesulfonic acid; and phosphoric acid group-containing monomers such as 2-hydroxyethylacryloyl phosphate. These can be used alone or in combination.

Further, vinyl monomers such as vinyl acetate, vinyl propionate, styrene, α-methylstyrene, N-vinylcaprolactam; epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate; polyethylene glycol (meth) acrylate; Glycol-based acrylic ester monomers such as polypropylene glycol (meth) acrylate, methoxyethylene glycol (meth) acrylate, and methoxypropylene glycol (meth) acrylate; tetrahydrofurfuryl (meth) acrylate, fluorine (meth) acrylate, silicone (meth) ) Acrylic ester-based monomers such as acrylate and 2-methoxyethyl acrylate can also be used. These can be used alone or in combination.

From the viewpoint of improving the cohesive force of the (meth) acrylic polymer and more effectively suppressing the generation of the nanoslit, the carboxyl group-containing monomer, the hydroxyl group-containing monomer, the nitrogen-containing monomer, and the aromatic Preferably, at least one polar monomer selected from group-containing monomers (excluding the (meth) acryloyl group-containing monomer (b2)) is introduced into the (meth) acrylic polymer by copolymerization, more preferably. Introduces the carboxyl group-containing monomer, the hydroxyl group-containing monomer, and the nitrogen-containing monomer into the (meth) acrylic polymer by copolymerization. As the carboxyl group-containing monomer, (meth) acrylic acid is preferred. The 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 nitrogen-containing monomer is preferably a vinyl monomer having a lactam ring, more preferably the vinyl pyrrolidone monomer, and further preferably N-vinyl pyrrolidone. By introducing the nitrogen-containing monomer into the (meth) acrylic polymer by copolymerization, the generation of nanoslits can be more effectively suppressed, and the durability of the pressure-sensitive adhesive layer at high temperature and / or high humidity can be improved. Properties (peeling resistance) can be improved. The aromatic group-containing monomer is preferably phenoxyethyl (meth) acrylate.

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

The (meth) acrylic polymer preferably contains 0.01 to 1% by weight of the hydroxyl group-containing monomer as a monomer unit, more preferably 0.05 to 1% by weight, and further preferably 0.1 to 1% by weight. ０．５0.5% by weight.

The (meth) acrylic polymer preferably contains 0.1 to 5% by weight of the nitrogen-containing monomer as a monomer unit, more preferably 0.5 to 3% by weight, and still more preferably 1.5 to 3% by weight. ３3% by weight.

The (meth) acrylic polymer preferably contains 1 to 20% by weight, more preferably 1 to 18% by weight, and still more preferably 1 to 15% by weight of the aromatic group-containing monomer as a monomer unit. It is.

The weight average molecular weight of the (meth) acrylic polymer is not particularly limited, but is preferably 1.5 million or less, more preferably 1.4 million or less, and still more preferably 1.3 million from the viewpoint of coatability of the pressure-sensitive adhesive. It is as follows. Further, from the viewpoints of adhesive properties, weather resistance, heat resistance, and the like, the weight average molecular weight is usually 800,000 or more, preferably 1,000,000 or more.

The (meth) acrylic polymer can be produced by a known method, and for example, a radical polymerization method such as a bulk polymerization method, a solution polymerization method, and a suspension polymerization method can be appropriately selected. As the radical polymerization initiator, various known azo-based and peroxide-based initiators can be used. The reaction temperature is usually about 50 to 80 ° C., and the reaction time is 1 to 8 hours. Among the above production methods, a solution polymerization method is preferable, and as a solvent for the (meth) acrylic polymer, ethyl acetate, toluene, and the like are generally used.

架橋 A cross-linking agent can be blended with the pressure-sensitive adhesive. The crosslinking agent can improve the adhesiveness and durability, and can maintain the reliability at a high temperature and maintain the shape of the pressure-sensitive adhesive itself. As a crosslinking agent, an isocyanate type, an epoxy type, a peroxide type, a metal chelate type, an oxazoline type or the like can be appropriately used. These crosslinking agents can be used alone or in combination of two or more.

イソシアネート As the isocyanate-based crosslinking agent, an isocyanate compound is used. As the isocyanate compound, isocyanate monomers such as tolylene diisocyanate, chlorphenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, and these isocyanates Adduct-based isocyanate compounds obtained by adding monomers to trimethylolpropane or the like; urethane prepolymers obtained by addition-reaction of isocyanurates, burette-type compounds, and known polyether polyols, polyester polyols, acrylic polyols, polybutadiene polyols, polyisoprene polyols, and the like. Polymeric isocyanates and the like can be mentioned.

The above isocyanate-based crosslinking agents may be used alone or in a combination of two or more, but the total content is based on 100 parts by weight of the base polymer. Preferably, the crosslinking agent is contained in an amount of 0.01 to 2 parts by weight, more preferably 0.02 to 2 parts by weight, and even more preferably 0.05 to 1.5 parts by weight. preferable. It can be appropriately contained in consideration of cohesion, prevention of peeling in a durability test, and the like.

各種 Various peroxides are used as the peroxide-based crosslinking agent. As the peroxide, di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxy neodecanoate , T-hexylperoxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxyisobutyrate, 1 , 1,3,3-tetramethylbutylperoxy 2-ethylhexanoate, di (4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, and the like. Among these, di (4-t-butylcyclohexyl) peroxydicarbonate, dilauroyl peroxide, and dibenzoyl peroxide, which are particularly excellent in crosslinking reaction efficiency, are preferably used.

The peroxides may be used each alone or two or more of them may be used as a mixture. However, the total content is 100 parts by weight of the base polymer and the peroxide. 0.01 to 2 parts by weight, preferably 0.04 to 1.5 parts by weight, more preferably 0.05 to 1 part by weight. In order to adjust the processability, reworkability, cross-linking stability, and releasability, it is appropriately selected within this range.

In order to obtain an adhesive layer having the adhesive strength P ₀ to P ₂ , the adhesive preferably contains a silane coupling agent. As the silane coupling agent, those having any appropriate functional group can be used. Examples of the functional group include a vinyl group, an epoxy group, an amino group, an acid anhydride group, a mercapto group, a (meth) acryloxy group, an acetoacetyl group, an isocyanate group, a styryl group, and a polysulfide group. Specifically, for example, a vinyl group-containing silane coupling agent such as vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane; γ-glycidoxypropyltrimethoxysilane, γ-glycol Epoxy group-containing silane coupling agents such as sidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane; γ-aminopropyltrimethoxysilane; N-β- (aminoethyl) -γ-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldimethoxysilane, γ-triethoxysilyl-N- (1,3-dimethylbutylidene) Propylamine, N-phenyl-γ Amino group-containing silane coupling agents such as aminopropyltrimethoxysilane; acid anhydride group-containing silane coupling agents such as 3-trimethoxysilylpropylsuccinic anhydride; mercapto group-containing silanes such as γ-mercaptopropylmethyldimethoxysilane Coupling agents; styryl group-containing silane coupling agents such as p-styryltrimethoxysilane; (meth) acryl group-containing silane coupling agents such as γ-acryloxypropyltrimethoxysilane and γ-methacryloxypropyltriethoxysilane; Isocyanate group-containing silane coupling agents such as 3-isocyanatopropyltriethoxysilane; and polysulfide group-containing silane coupling agents such as bis (triethoxysilylpropyl) tetrasulfide. These can be used alone or in combination. Among these, from the viewpoint of obtaining a pressure-sensitive adhesive layer that is difficult to peel off from a glass substrate or the like even when exposed to an environment where dew condensation occurs, an epoxy group, an isocyanate group, a mercapto group, an acid anhydride group, and a group consisting of an amino group It is preferable to use a silane coupling agent having at least one selected functional group, more preferably a silane coupling agent having an epoxy group, an isocyanate group, a mercapto group, or an acid anhydride group.

オリゴマー Also, an oligomer-type silane coupling agent may be used from the viewpoint of obtaining a pressure-sensitive adhesive layer that does not easily peel off from a glass substrate or the like even when exposed to an environment in which dew condensation occurs. Here, the oligomer type refers to a polymer of about 2 to less than 100 monomers, and the weight average molecular weight of the oligomer type silane coupling agent is preferably about 300 to 30,000.

Examples of the oligomer type silane coupling agent include an epoxy group-containing silane coupling agent, a mercapto group-containing silane coupling agent, and an isocyanate group-containing silane coupling agent, and are preferably a mercapto group-containing silane coupling agent. And a silane coupling agent containing an isocyanate group. These can be used alone or in combination.

The epoxy equivalent of the epoxy group-containing silane coupling agent is preferably from 250 to 600 g / mol, more preferably from 250 to 500 g / mol, from the viewpoint of durability of the pressure-sensitive adhesive layer under a high temperature and / or high humidity environment. mol, more preferably 280 to 400 g / mol.

The epoxy group-containing silane coupling agent preferably has two or more alkoxysilyl groups in the molecule. Further, the amount of the alkoxy group in the epoxy group-containing silane coupling agent is preferably 10 to 60% by weight, more preferably 20 to 50% by weight, and more preferably 20 to 40% by weight in the silane coupling agent. % Is more preferable. Further, the epoxy group-containing silane coupling agent has one or more epoxy groups in a molecule, but obtains an adhesive layer that is hard to peel off from a glass substrate or the like even when exposed to an environment where dew condensation occurs. From the viewpoint, it is preferable to have one epoxy group in the molecule. In addition, the epoxy group-containing silane coupling agent preferably has an aromatic ring in the molecule from the above viewpoint.

Oligomeric epoxy group-containing silane coupling agents having two or more alkoxysilyl groups in the molecule include, for example, X-12-981S, X-12-1231, X-41 manufactured by Shin-Etsu Chemical Co., Ltd. -1059A, X-41-1056 and the like.

The mercapto equivalent of the mercapto group-containing silane coupling agent is preferably 1,000 g / mol or less, and more preferably 800 g / mol or less, from the viewpoint of the durability of the pressure-sensitive adhesive layer under a high temperature and / or high humidity environment. More preferably, it is 700 g / mol or less, more preferably 500 g / mol or less. The lower limit of the mercapto equivalent is not particularly limited, but is preferably 200 g / mol or more.

The mercapto group-containing silane coupling agent preferably has two or more alkoxysilyl groups in the molecule. The amount of the alkoxy group in the mercapto group-containing silane coupling agent is preferably 10 to 60% by weight, more preferably 20 to 50% by weight, and more preferably 20 to 40% by weight in the silane coupling agent. % Is more preferable.

Oligomeric mercapto group-containing silane coupling agents having two or more alkoxysilyl groups in the molecule include, for example, X-41-1805, X-41-1810, and X-41 manufactured by Shin-Etsu Chemical Co., Ltd. -1818, X-12-1156 and the like.

The isocyanate equivalent of the isocyanate group-containing silane coupling agent is preferably from 250 to 600 g / mol, more preferably from 250 to 500 g / mol, from the viewpoint of the durability of the pressure-sensitive adhesive layer under a high temperature and / or high humidity environment. mol, more preferably 280 to 400 g / mol.

The isocyanate group-containing silane coupling agent preferably has two or more alkoxysilyl groups in the molecule. The amount of the alkoxy group in the isocyanate group-containing silane coupling agent is preferably 10 to 60% by weight, more preferably 20 to 50% by weight, and more preferably 20 to 40% by weight in the silane coupling agent. % Is more preferable.

Examples of the oligomer type isocyanate group-containing silane coupling agent having two or more alkoxysilyl groups in the molecule include X-40-9318 and X-12-1159L manufactured by Shin-Etsu Chemical Co., Ltd. .

The content of the entire silane coupling agent is preferably 0.05 to 5 parts by weight with respect to 100 parts by weight of the base polymer, from the viewpoint of obtaining a pressure-sensitive adhesive layer having the above-mentioned adhesive strength P ₀ to P _2. Preferably it is 0.1 to 3 parts by weight, more preferably 0.2 to 2 parts by weight.

Further, a silane coupling agent (including an oligomer type silane coupling agent) having at least one kind of functional group selected from the group consisting of an epoxy group, an isocyanate group, a mercapto group, an acid anhydride group, and an amino group. The content is preferably from 0.01 to 3 parts by weight, more preferably from 0.1 to 3 parts by weight, based on 100 parts by weight of the base polymer, from the viewpoint of obtaining a pressure-sensitive adhesive layer having the above-mentioned adhesive strength P ₀ to P _2. It is 2 parts by weight, more preferably 0.1 to 1 part by weight.

Further, it is preferable that the pressure-sensitive adhesive contains a rework improver from the viewpoint of improving reworkability. The rework improver is a chemical substance having a polar group, easily interacting with the glass interface, and easily segregating at the glass interface. Examples of the rework improver include diols having an alkyleneoxy group such as EO and PO, oligomers having a perfluoroalkyl group, and polyether compounds having a reactive silyl group. As the polyether compound, for example, those disclosed in JP-A-2010-275522 can be used.

Examples of the polyether compound having a reactive silyl group include, for example, MS polymers S203, S303, and S810 manufactured by Kaneka Corporation; SILYL @ EST250, EST280; Or S3430 and the like.

The content of the rework improver is preferably at least 0.001 part by weight, more preferably at least 0.01 part by weight, still more preferably at least 0.1 part by weight, based on 100 parts by weight of the base polymer. It is preferably at most 10 parts by weight, more preferably at most 5 parts by weight, further preferably at most 2 parts by weight, still more preferably at most 1 part by weight. When the content of the rework improver is less than 0.001 part by weight, it is difficult to improve the reworkability of the pressure-sensitive adhesive layer, and when it exceeds 10 parts by weight, the pressure-sensitive adhesive property of the pressure-sensitive adhesive layer tends to decrease.

Furthermore, the pressure-sensitive adhesive preferably contains an antistatic agent. At the time of manufacturing the liquid crystal display device, when the piece protective polarizing film with the adhesive layer is attached to the liquid crystal panel, the release film is peeled from the adhesive layer of the piece protective polarizing film with the adhesive layer. Separation generates static electricity. In addition, when bonding a piece-protecting polarizing film with an adhesive layer to a liquid crystal panel, if a bonding error occurs, it is necessary to peel the polarizing film, but the peeling of the polarizing film generates static electricity. . The generated static electricity affects the orientation of the liquid crystal inside the liquid crystal display device, and causes a defect. In addition, display unevenness may occur due to static electricity when the liquid crystal display device is used. By adding an antistatic agent to the pressure-sensitive adhesive, an antistatic function can be imparted to the pressure-sensitive adhesive layer of the piece-protected polarizing film with a pressure-sensitive adhesive layer, and these problems can be prevented.

は The antistatic agent is not particularly limited, and examples thereof include ionic compounds such as onium-anion salts and alkali metal salts. When an ionic compound is added, it is considered that the antistatic function is efficiently exhibited by bleeding out of the ionic compound on the surface of the pressure-sensitive adhesive layer. On the other hand, when the ionic compound comes into contact with the polarizer, optical characteristics such as the degree of polarization may be reduced. From the viewpoint of suppressing a decrease in the optical characteristics, it is particularly preferable to use an alkali metal salt.

は As the alkali metal salt, an organic salt or an inorganic salt of an alkali metal can be used. One alkali metal salt may be used alone, or two or more alkali metal salts may be used in combination.

アルカリ Examples of the alkali metal ion constituting the cation portion of the alkali metal salt include lithium, sodium, and potassium ions. Among these alkali metal ions, lithium ions are preferred.

The anion part of the alkali metal salt may be composed of an organic substance or may be composed of an inorganic substance. Examples of the anion part constituting the organic salt include CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , and (CF ₃ SO ₂ ). _{^{_{_{3 C -, C 4 F 9}}}} SO 3 -, (C 2 F 5 SO 2) 2 N -, C 3 F 7 COO -, (CF 3 SO 2) (CF 3 CO) N -, - O 3 S ( CF ₂ ) ₃ SO ₃ ⁻ , PF ₆ ⁻ , CO ₃ ^2- , and the like are used. In particular, an anion portion containing a fluorine atom is preferably used because an ionic compound having good ion dissociation can be obtained. Examples of the anion portion constituting the inorganic salt include Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , AsF ₆ ⁻ , and SbF. ₆ ⁻ , NbF ₆ ⁻ , TaF ₆₋ , (CN) ₂ N ⁻ and the like are used. As the anion part, (perfluoroalkylsulfonyl) imides such as (CF ₃ SO ₂ ) ₂ N ⁻ and (C ₂ F ₅ SO ₂ ) ₂ N ⁻ are preferable, and particularly represented by (CF ₃ SO ₂ ) ₂ N ⁻ . (Trifluoromethanesulfonyl) imide is preferred.

Specific examples of the alkali metal organic salt include sodium acetate, sodium alginate, sodium lignin sulfonate, sodium toluene sulfonate, LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, and Li (CF ₃ SO _2). ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, Li (C ₄ F ₉ SO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₃ C, KO ₃ S (CF ₂ ) ₃ SO ₃ K, LiO ₃ S (CF ₂ ) ₃ SO ₃ K and the like, among which LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, Li (C ₄₎ F ₉ SO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₃ C and the like are preferable, and Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, Li (C ₄ F ₉ SO) ₂₎ ₂ Fluorine-containing lithium imide salt is more preferably equal, particularly (perfluoroalkyl sulfonyl) imide lithium salts are preferred.

Also, examples of the inorganic salt of an alkali metal include lithium perchlorate and lithium iodide.

アルカリ The content of the alkali metal salt in the adhesive is preferably 0.001 to 5 parts by weight based on 100 parts by weight of the base polymer. If the amount of the alkali metal salt is less than 0.001 part by weight, the effect of improving the antistatic performance may not be sufficient. The content of the alkali metal salt is preferably at least 0.01 part by weight, and more preferably at least 0.1 part by weight. On the other hand, if the content of the alkali metal salt is more than 5 parts by weight, the durability may not be sufficient. The content of the alkali metal salt is preferably 3 parts by weight or less.

As a method of forming the pressure-sensitive adhesive layer, for example, the pressure-sensitive adhesive is applied to a separator or the like that has been subjected to a release treatment, and a polymerization solvent or the like is removed by drying to form a pressure-sensitive adhesive layer. It is prepared by a method of transferring to a polarizer in the embodiment of FIG. 1, or a method of applying the adhesive, drying and removing a polymerization solvent or the like, and forming an adhesive layer on the polarizer side. In applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be newly added as appropriate.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is preferably 25 μm or less, more preferably 23 μm or less, and still more preferably, from the viewpoint of effectively suppressing defects due to the nanoslit and achieving both excellent adhesive properties and reworkability. It is 20 μm or less, preferably 10 μm or more, more preferably 12 μm or more, and still more preferably 15 μm or more.

シリコーン Silicone release liners are preferably used as the release-treated separator. In the step of applying and drying the pressure-sensitive adhesive of the present invention on such a liner to form a pressure-sensitive adhesive layer, an appropriate method may be employed as a method for drying the pressure-sensitive adhesive, depending on the purpose. Preferably, a method of heating and drying the coating film is used. The heating and drying temperature is preferably from 40 ° C to 200 ° C, more preferably from 50 ° C to 180 ° C, and particularly preferably from 70 ° C to 170 ° C. By setting the heating temperature in the above range, an adhesive having excellent adhesive properties can be obtained.

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

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

When the pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected by a sheet (separator) that has been subjected to a release treatment until it is practically used.

As a constituent material of the separator, for example, polyethylene, polypropylene, polyethylene terephthalate, a plastic film such as a polyester film, paper, cloth, a porous material such as a nonwoven fabric, a net, a foamed sheet, a metal foil, and a laminate of these as appropriate Although a thin leaf body and the like can be mentioned, a plastic film is preferably used because of its excellent surface smoothness.

The plastic film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. Examples of the plastic film include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, and vinyl chloride film. Examples include a polymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

セパレータ The thickness of the separator is usually about 5 to 200 μm, preferably about 5 to 100 μm. The separator, if necessary, silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, release and antifouling treatment with silica powder, etc., coating type, kneading type, evaporation type It is also possible to perform an antistatic treatment such as In particular, by appropriately performing a release treatment such as a silicone treatment, a long-chain alkyl treatment, or a fluorine treatment on the surface of the separator, the releasability from the pressure-sensitive adhesive layer can be further improved.

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

フィルム As the base film of the surface protective film, a film material having or close to isotropicity is selected from the viewpoint of testability and manageability. Examples of the film material include a polyester resin such as a polyethylene terephthalate film, a cellulose resin, an acetate resin, a polyether sulfone resin, a polycarbonate resin, a polyamide resin, a polyimide resin, a polyolefin resin, and an acrylic resin. A transparent polymer such as a resin can be used. Of these, polyester resins are preferred. The base film can be used as a laminate of one or more film materials, and a stretched product of the film can also be used. The thickness of the substrate film is generally 500 μm or less, preferably 10 to 200 μm.

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

In addition, on the surface protective film, a release treatment layer can be provided on the surface opposite to the surface on which the pressure-sensitive adhesive layer of the base film is provided, using a low-adhesion material such as silicone treatment, long-chain alkyl treatment, or fluorine treatment. .

<Other optical layers>
The piece-protecting polarizing film provided with the pressure-sensitive adhesive layer of the present invention can be used as an optical film laminated with another optical layer in practical use. The optical layer is not particularly limited. For example, it is used for forming a liquid crystal display device such as a reflection plate, a semi-transmission plate, a retardation plate (including a wavelength plate such as や or や), a viewing angle compensation film, and the like. One or more optical layers that may be used may be used. In particular, a reflective polarizing film or a semi-transmissive polarizing film in which a reflective plate or a semi-transmissive reflective plate is further laminated on the pressure-sensitive adhesive layer-attached piece-protected polarizing film, and a further retardation to the pressure-sensitive adhesive layer-attached piece-protected polarizing film. An elliptically polarizing film or a circularly polarizing film obtained by laminating plates, a wide viewing angle polarizing film obtained by further laminating a viewing angle compensating film on a protective film with an adhesive layer, or a polarizing film having a protective film with an adhesive layer A polarizing film in which an enhancement film is laminated is preferable.

The optical film obtained by laminating the above-mentioned optical layer on the piece protective polarizing film with an adhesive layer can also be formed by a method of sequentially laminating the optical film in a manufacturing process of a liquid crystal display device or the like, but it is possible to form the optical film by laminating in advance. This is superior in quality stability and assembling work, and has an advantage that the manufacturing process of a liquid crystal display device or the like can be improved. Appropriate bonding means such as a pressure-sensitive adhesive layer can be used for lamination. In bonding the above-mentioned piece-protecting polarizing film with an adhesive layer and other optical films, their optical axes can be set at an appropriate angle according to the intended retardation characteristics and the like.

片 The piece-protected polarizing film or optical film with an adhesive layer of the present invention can be preferably used for forming various image display devices such as a liquid crystal display device and an organic EL display device. The formation of the liquid crystal display device can be performed according to a conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell and a piece-protected polarizing film or optical film with an adhesive layer, and an illumination system as necessary, and incorporating a drive circuit. In the present invention, there is no particular limitation except that a piece-protective polarizing film or an optical film with a pressure-sensitive adhesive layer according to the present invention is used. As the liquid crystal cell, any type such as an IPS type and a VA type can be used, but the liquid crystal cell is particularly suitable for the IPS type.

It is possible to form an appropriate liquid crystal display device such as a liquid crystal display device in which a piece protective polarizing film or optical film with an adhesive layer is disposed on one or both sides of a liquid crystal cell, or a lighting system using a backlight or a reflector. it can. In that case, the piece-protecting polarizing film or optical film with the pressure-sensitive adhesive layer according to the present invention can be installed on one side or both sides of the liquid crystal cell. When a piece-protecting polarizing film or an optical film with a pressure-sensitive adhesive layer is provided on both sides, they may be the same or different. Further, when forming the liquid crystal display device, for example, a suitable component such as a diffusion plate, an anti-glare layer, an antireflection film, a protection plate, a prism array, a lens array sheet, a light diffusion plate, a backlight, etc. Two or more layers can be arranged.

<Continuous manufacturing method of image display device>
The above-mentioned image display device comprises the above-mentioned pressure-sensitive adhesive layer-attached polarizing film with an adhesive layer, which is unwound from a roll of the pressure-sensitive adhesive layer-attached one-piece protective film of the present invention and conveyed by the separator. It is preferable to be manufactured by a continuous manufacturing method (roll-to-panel method) including a step of continuously bonding to the surface of the image display panel through the process. Since the piece-protecting polarizing film with the pressure-sensitive adhesive layer of the present invention is a very thin film, it is cut into sheets (sheet-by-sheet cutting) and then bonded to the image display panel one by one (“sheet-to-panel method”). )), It is difficult to handle the sheet at the time of transporting the sheet or laminating it to the display panel, and in the process, the piece-protecting polarizing film (sheet) with the adhesive layer undergoes a large mechanical impact (for example, bending due to adsorption). Etc.). In order to reduce such a risk, for example, a countermeasure such as using a thicker surface protective film having a thickness of the base film of 50 μm or more is required separately. On the other hand, according to the roll-to-panel method, the piece-protected polarizing film with the pressure-sensitive adhesive layer is stably conveyed from the roll to the image display panel by the continuous separator without being cut into sheets (sheet-by-sheet cutting). Then, since the film is directly attached to the image display panel, the risk can be significantly reduced without using a thick surface protection film. As a result, combined with the fact that the pressure-sensitive adhesive layer in which the film thickness and the storage elastic modulus are controlled to satisfy a predetermined relational expression can alleviate the mechanical impact, an image display in which the generation of nanoslits is effectively suppressed is achieved. Panels can be continuously produced at high speed.

FIG. 5 is a schematic diagram showing an example of a continuous manufacturing system for a liquid crystal display device employing a roll-to-panel method. As shown in FIG. 5, the continuous manufacturing system 100 for a liquid crystal display device includes a series of transport units X for transporting a liquid crystal display panel P, a first polarizing film supply unit 101a, a first bonding unit 201a, and a second polarizing film supply. And a second bonding part 201b. The wound body (first roll) 20a of the piece-protecting polarizing film with the first pressure-sensitive adhesive layer and the wound body (second roll) 20b of the piece-protecting polarizing film with the second pressure-sensitive adhesive layer absorb in the longitudinal direction. The one having a shaft and having the mode shown in FIG. 1 is used.

(Transportation section)
The transport section X transports the liquid crystal display panel P. The transport unit X includes a plurality of transport rollers, a suction plate, and the like. The transport unit X is arranged between the first bonding unit 201a and the second bonding unit 201b to exchange the positional relationship between the long side and the short side of the liquid crystal display panel P with respect to the transport direction of the liquid crystal display panel P. A replacement unit (for example, horizontally rotating the liquid crystal display panel P by 90 °) 300 is included. Thus, the first protective polarizing film with an adhesive layer 21a and the second protective polarizing film with an adhesive layer 21b can be bonded to the liquid crystal display panel P in a cross-Nicol relationship.

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

１The first feeding portion 151a has a feeding shaft on which the first roll 20a is set, and feeds the strip-shaped pressure-sensitive adhesive layer-attached protective film 21a provided with the separator 5a from the first roll 20a.

The first cutting unit 152a has a cutting unit such as a cutter and a laser device, and a suction unit. The first cutting portion 152a cuts the band-shaped first protective polarizing film with an adhesive layer 21a in the width direction at a predetermined length while leaving the separator 5a. However, as the first roll 20a, a strip-shaped protective film 21a with a pressure-sensitive adhesive layer having a plurality of cut lines formed in the width direction at a predetermined length is laminated on the separator 5a (notched optical fiber). When a film roll is used, the first cutting portion 152a becomes unnecessary (the same applies to a second cutting portion 152b described later).

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

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

(First lamination part)
The first bonding portion 201a is formed by attaching the first adhesive layer-attached piece-protected polarizing film 21a peeled by the first peeling portion 153a to the liquid crystal display panel P transported by the transport portion X, Continuous bonding is performed via the pressure-sensitive adhesive layer of the protective polarizing film 21a (first bonding step). The first bonding section 81 includes a pair of bonding rollers, and at least one of the bonding rollers is configured by a driving roller.

(Second polarizing film supply unit)
The second polarizing film supply unit 101b continuously feeds the one-piece protective polarizing film with an adhesive layer (with a surface protective film) 21b unwound from the second roll 20b and transported by the separator 5b to the second bonding unit 201b. To supply. The second polarizing film supply unit 101b includes a second feeding unit 151b, a second cutting unit 152b, a second peeling unit 153b, a second winding unit 154b, and a plurality of transport roller units, an accumulating unit such as a dancer roll, and the like. Have. The second feeding portion 151b, the second cutting portion 152b, the second peeling portion 153b, and the second winding portion 154b include a first feeding portion 151a, a first cutting portion 152a, a first peeling portion 153a, and a first winding portion, respectively. It has a configuration and a function similar to those of the taking section 154a.

(2nd bonding part)
The second bonding unit 201b is configured to attach the second adhesive layer-attached piece-protected polarizing film 21b peeled by the second peeling unit 153b to the liquid crystal display panel P transported by the transport unit X, Continuous bonding is performed via the pressure-sensitive adhesive layer of the protective polarizing film 21b (second bonding step). The second bonding unit 201b includes a pair of bonding rollers, and at least one of the bonding rollers is configured by a driving roller.

本 Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the examples described below. In addition, all parts and% in each example are based on weight. The room temperature storage conditions not particularly specified below are all 23 ° C. and 55% RH.

<Preparation of one-sided protective polarizing film>
(Preparation of polarizer)
A corona treatment is applied to one surface of an amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) having a water absorption of 0.75% and Tg of 75 ° C. Alcohol (degree of polymerization 4200, degree of saponification 99.2 mol%) and acetoacetyl-modified PVA (degree of polymerization 1200, degree of acetoacetyl modification 4.6%, degree of saponification 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd. And an aqueous solution containing 9: 1 (trade name “Gosefimer Z200”) at 25 ° C. was applied and dried to form a 11 μm-thick PVA-based resin layer to prepare a laminate.
The obtained laminate was uniaxially stretched 2.0 times in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 120 ° C. with free-end uniaxial stretching (in-air auxiliary stretching treatment).
Next, the laminate was immersed in an insolubilizing bath at a liquid temperature of 30 ° C. (a boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilization treatment).
Next, it was immersed in a dyeing bath at a liquid temperature of 30 ° C. while adjusting the iodine concentration and the immersion time so that the polarizing plate had a predetermined transmittance. In the present example, 0.2 part by weight of iodine was added to 100 parts by weight of water, and the resultant was immersed in an aqueous solution of iodine obtained by mixing 1.0 part by weight of potassium iodide for 60 seconds (dyeing treatment). .
Next, it was immersed in a crosslinking bath at a liquid temperature of 30 ° C. (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).
Thereafter, the laminate is immersed in an aqueous solution of boric acid at a liquid temperature of 70 ° C. (an aqueous solution obtained by mixing 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with respect to 100 parts by weight of water). Meanwhile, uniaxial stretching was performed between rolls having different peripheral speeds in the longitudinal direction (longitudinal direction) so that the total stretching ratio became 5.5 times (underwater stretching treatment).
Thereafter, the laminate was immersed in a washing bath at a liquid temperature of 30 ° C. (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) (washing treatment).
Thus, an optical film laminate including a polarizer having a thickness of 5 μm and a boric acid content of 16% was obtained. The boric acid content in the polarizer was measured by the following method.

The obtained polarizer was subjected to boric acid by attenuated total reflection spectroscopy (ATR) measurement using polarized light as measurement light using a Fourier transform infrared spectrophotometer (FTIR) (trade name “SPECTRUM2000” manufactured by Perkin Elmer). The intensity of the peak (665 cm ^-1 ) and the intensity of the reference peak (2941 cm ^-1 ) were measured. The boric acid content index was calculated from the obtained boric acid peak intensity and reference peak intensity by the following formula, and the boric acid content (% by weight) was determined from the calculated boric acid content index by the following formula.
(Boric acid content index) = (intensity of boric acid peak 665 cm ⁻¹ ) / (intensity of reference peak 2941 cm ⁻¹ )
(Boric acid content (% by weight)) = (Boric acid content index) × 5.54 + 4.1

(Preparation of transparent protective film)
Transparent protective film: A (meth) acrylic resin film having a lactone ring structure having a thickness of 40 μm was subjected to a corona treatment on an easily-adhered surface.

(Preparation of adhesive applied to transparent protective film)
40 parts by weight of N-hydroxyethylacrylamide (HEAA), 60 parts by weight of acryloylmorpholine (ACMO) and 3 parts by weight of a photoinitiator “IRGACURE 819” (manufactured by BASF) were mixed to prepare an ultraviolet-curable adhesive.

(Preparation of one-sided protective polarizing film)
On the surface of the polarizer of the optical film laminate, while applying the ultraviolet-curable adhesive so that the thickness of the adhesive layer after curing becomes 0.5 μm, the transparent protective film is laminated, and then the active film is activated. Ultraviolet rays were irradiated as energy rays to cure the adhesive. Irradiation with ultraviolet light is performed using a gallium-filled metal halide lamp, irradiation apparatus: Light HAMMER10 manufactured by Fusion UV Systems, Inc., bulb: V bulb, peak illuminance: 1600 mW / cm ² , cumulative irradiation amount 1000 / mJ / cm ² (wavelength 380 to 440 nm) ) And the UV illumination was measured using a Sola-Check system from Solatell. Next, the amorphous PET substrate was peeled off, and a one-sided protective polarizing film using a thin polarizer was produced. Using the obtained one-sided protective polarizing film, the simplex transmittance T and the degree of polarization P of the polarizer were measured by the following method. The simplex transmittance T of the polarizer was 42.8%, and the degree of polarization P of the polarizer was 99.99%.

The simplex transmittance T and the degree of polarization P of the polarizer of the obtained one-sided protective polarizing film were measured using a spectral transmittance meter with an integrating sphere (Dot-3c, Murakami Color Research Laboratory).
The degree of polarization P is such that the transmittance (parallel transmittance: Tp) when two identical one-side protective polarizing films are superposed so that their transmission axes are parallel to each other and the transmission axes of both are orthogonal to each other. Is obtained by applying the transmittance (orthogonal transmittance: Tc) when superimposed on the following equation. Degree of polarization P (%) = {(Tp−Tc) / (Tp + Tc)} ^1/2 × 100
Each transmittance is represented by a Y value obtained by correcting luminosity by a 2-degree field of view (C light source) according to JIS Z8701, with 100% of completely polarized light obtained through a Glan-Teller prism polarizer.

<Preparation of both protective polarizing films>
A polyvinyl alcohol film having a thickness of 80 μm was stretched up to 3 times while being dyed in a 0.3% by weight iodine solution at 30 ° C. for 1 minute between rolls having different speed ratios. Thereafter, the film was stretched to a total stretch ratio of 6 while immersing it in an aqueous solution containing boric acid at a concentration of 4% by weight and a potassium iodide at a concentration of 10% by weight for 0.5 minutes at 60 ° C. Next, after washing by immersion in an aqueous solution containing 1.5% by weight of potassium iodide at 30 ° C. for 10 seconds, drying was performed at 50 ° C. for 4 minutes to obtain a polarizer having a thickness of 30 μm. A saponified triacetyl cellulose film having a thickness of 80 μm was attached to both surfaces of the polarizer with a polyvinyl alcohol-based adhesive to prepare both protective polarizing films.

<Formation of adhesive layer>
(Preparation of acrylic pressure-sensitive adhesive 1)
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 89.78 parts of n-butyl acrylate, 8 parts of methyl methacrylate, 1.5 parts of N-vinylpyrrolidone, 0.2 parts of acrylic acid And a monomer mixture containing 0.48 parts of 4-hydroxybutyl acrylate. Further, with respect to 100 parts of the monomer mixture (solid content), 0.15 part of 2,2′-azobisisobutyronitrile as a polymerization initiator was charged together with ethyl acetate, and nitrogen gas was introduced with gentle stirring. After replacing with nitrogen, the polymerization reaction was carried out for 7 hours while maintaining the liquid temperature in the flask at around 60 ° C. Thereafter, ethyl acetate was added to the obtained reaction solution to prepare a solution of an acrylic polymer having a weight-average molecular weight of 1.3 million and adjusted to a solid concentration of 20%.

The weight average molecular weight (Mw) of the acrylic polymer was measured using a GPC device (HLC-8220GPC) manufactured by Tosoh Corporation. The measurement conditions are as follows.
Sample concentration: 0.2% by mass (THF solution)
Sample injection volume: 10 μl
Eluent: THF
Flow rate: 0.6 ml / min
Measurement temperature: 40 ° C
Column: sample column; TSKguardcolumn SuperHZ-H (1) + TSKgel SuperHZM-H (2)
Reference column: TSKgel SuperH-RC (1)
Detector: Differential refractometer (RI)
The weight average molecular weight was determined in terms of polystyrene.

With respect to 100 parts of the solid content of the prepared acrylic polymer solution, 1.5 parts of lithium bis (trifluoromethanesulfonyl) imide (manufactured by Mitsubishi Materials Electronic Chemicals), 1.5 parts of ethylmethylpyrrolidinium-bis (trifluoromethanesulfonyl) imide ( 1 part of Tokyo Kasei Kogyo Co., Ltd., 0.25 parts of isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, trade name "Takenate D160N"), and 0 of peroxide-based cross-linking agent (manufactured by NOF Corporation, trade name "Niper BMT40SV") 0 25 parts, 0.1 part of rework improver (manufactured by Kaneka Corporation, trade name "SAT10"), 0.3 parts of antioxidant (manufactured by BASF Japan, trade name "Irganox @ 1010"), acetoacetyl group-containing silane cup 0.2 parts of a ring agent (trade name “A-100” manufactured by Soken Chemical Co., Ltd.) and an oligomer type mercapto group-containing resin Coupling agent (Shin-Etsu Chemical Co., Ltd., trade name "X-41-1810") by blending 0.2 parts to prepare an acrylic pressure-sensitive adhesive 1.

(Preparation of acrylic pressure-sensitive adhesives 2 to 27)
In the preparation of the acrylic pressure-sensitive adhesive 1, a similar method was used except that the composition of the monomers was changed as shown in Table 1, the polymerization conditions were adjusted, and the types and amounts of the additives were changed as shown in Table 1. To prepare a solution of an acrylic polymer, and acrylic adhesives 2 to 27 were prepared.

(Formation of adhesive layer)
Next, the prepared acrylic pressure-sensitive adhesives 1 to 27 are uniformly applied to the surface of a polyethylene terephthalate film (separator film) treated with a silicone-based release agent, respectively, with a fountain coater. For 1 minute to form an adhesive layer on the surface of each separator film.

The compounds in Table 1 are as follows.
BA: n-butyl acrylate 4HBA: 4-hydroxybutyl acrylate AA: acrylic acid NVP: N-vinylpyrrolidone MMA: methyl methacrylate PEA: 2-phenoxyethyl acrylate Niper BMT40SV: dibenzoyl peroxide D160N: isocyanate crosslinking agent (Mitsui Chemicals Company)
D110N: Isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc.)
C / L: Trimethylolpropane / tolylene diisocyanate adduct (trade name "Coronate L" manufactured by Tosoh Corporation)
SAT10: Rework improver (manufactured by Kaneka Corporation)
LiTFSi: lithium bis (trifluoromethanesulfonyl) imide (manufactured by Mitsubishi Materials Electronic Chemicals)
EMPTFSi: Ethylmethylpyrrolidinium-bis (trifluoromethanesulfonyl) imide (Tokyo Kasei Kogyo)
Irganox 1010: Antioxidant (manufactured by BASF Japan)
A-100: Acetoacetyl group-containing silane coupling agent (manufactured by Soken Chemical Co., Ltd.)
X-41-1810: oligomer type mercapto group-containing silane coupling agent (Shin-Etsu Chemical Co., Ltd.)
KBM-573: N-phenyl-3-aminopropyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd.)
X-12-1156: oligomer type mercapto group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.)
X-40-9318: oligomer type isocyanate group-containing silane coupling agent (Shin-Etsu Chemical Co., Ltd.)
X-88-398: Amino group-containing silane coupling agent (Shin-Etsu Chemical Co., Ltd.)
KBM-6803: N-2- (aminoethyl) -8-aminooctyltrimethoxysilane (Shin-Etsu Chemical Co., Ltd.)
X-12-5263H: Amino group alkoxy polyfunctional group-containing silane coupling agent (Shin-Etsu Chemical Co., Ltd.)
X-12-981S: Organosilane (Shin-Etsu Chemical Co., Ltd.)
X-12-1159L: oligomer type isocyanate group-containing silane coupling agent (Shin-Etsu Chemical Co., Ltd.)
X-121231: Epoxy group-containing silane coupling agent (Shin-Etsu Chemical Co., Ltd.)
X-41-1056: oligomer type epoxy group-containing silane coupling agent (Shin-Etsu Chemical Co., Ltd.)
X-24-9591F: oligomeric acid anhydride group-containing silane coupling agent (Shin-Etsu Chemical Co., Ltd.)
TMPS-E: Amino group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.)
X-12-967C: 3-trimethoxysilylpropylsuccinic anhydride (manufactured by Shin-Etsu Chemical Co., Ltd.)
KBM-3086: Alkoxy polyfunctional group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.)
KBE-9007N: isocyanate group-containing silane coupling agent (Shin-Etsu Chemical Co., Ltd.)
KBM-803: 3-mercaptopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.)
X-12-1056ES: Mercapto group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd.)
KBM-403: 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.)

Examples 1 to 19, Comparative Examples 1 to 11
<Preparation of one-sided protective polarizing film with adhesive layer>
The prepared pressure-sensitive adhesive layers were bonded to the polarizer side of the prepared piece-protected polarizing film, respectively, to prepare piece-protected polarizing films with a pressure-sensitive adhesive layer.
<Preparation of double protective polarizing film with adhesive layer>
The prepared pressure-sensitive adhesive layers were bonded to one side of both of the prepared protective polarizing films, respectively, to prepare both protective polarizing films with a pressure-sensitive adhesive layer.

について The following measurements and evaluations were performed on the pressure-sensitive adhesive layer, the one-sided protective polarizing film with the pressure-sensitive adhesive layer, and the two protective polarizing films with the pressure-sensitive adhesive layer obtained above. Table 2 shows the results.

<Suppression of nanoslit: Guitar pick test>
Sample 11 was prepared by cutting the prepared piece protective polarizing film with an adhesive layer and both protective polarizing films with an adhesive layer into a size of 50 mm x 150 mm (the absorption axis direction was 50 mm). Sample 11 was used by attaching a surface protective film 6 produced by the following method to the protective film 2 side.

(Surface protection film for testing)
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 94 parts by mass of 2-ethylhexyl acrylate (2EHA), 1 part by mass of N, N-diethylacrylamide (DEAA), ethoxydiethylene glycol acrylate ( 1 part by mass of 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 are charged, and gently stirred. While introducing a nitrogen gas, the polymerization reaction was carried out for 5 hours while maintaining the liquid temperature in the flask at around 60 ° C. to prepare an acrylic polymer solution (40% by mass). The acrylic polymer had a weight average molecular weight of 570,000 and a glass transition temperature (Tg) of -68 ° C.
The acrylic polymer solution (40% by mass) was diluted to 20% by mass with ethyl acetate, and 500 parts by mass (100 parts by mass of solid content) of this solution were mixed with an isocyanurate of hexamethylene diisocyanate (Coronate, manufactured by Nippon Polyurethane Industry Co., Ltd.). HX: C / HX) 2 parts by mass (solids content 2 parts by mass), 2 parts by mass of dibutyltin dilaurate (1% by mass ethyl acetate solution) (solids content 0.02 parts by mass) as a crosslinking catalyst were added, and the mixture was stirred. Then, an acrylic pressure-sensitive adhesive solution was prepared.
The acrylic pressure-sensitive adhesive solution is applied to a 38 μm-thick transparent polyethylene terephthalate (PET) film (polyester film) and heated at 130 ° C. for 1 minute to form a 15 μm-thick pressure-sensitive adhesive layer to protect the surface. A film was prepared.

Next, as shown in the conceptual diagram of FIG. 3A and the cross-sectional view of FIG. 3B, the release sheet (separator) is peeled off from the sample 11 and the glass plate 20 is exposed via the exposed adhesive layer 4. Pasted on top. Next, a 200 g load was applied to the central portion of the sample 11 (surface protective film 6 side) by a guitar pick (manufactured by HISTORY, model number “HP2H (HARD))” to apply the absorption axis of the polarizer 1 in the sample 11. A load of 50 reciprocations was repeated at a distance of 100 mm in the orthogonal direction. The load was applied at one location. The load was applied at a high speed (7.5 m / min).
Next, the sample 11 was allowed to stand in an environment of 80 ° C. for 1 hour, and then the presence or absence of cracks in light leakage of the sample 11 was confirmed according to the following criteria.
◎: 0 to 10 ○: 11 to 30 ×: 31 or more

FIG. 4 is an example of a microscopic photograph of the polarizing film surface, which serves as the following index for confirming cracks (nano slits a) of light leakage in the guitar pick test of the piece-protecting polarizing film 11 with the adhesive layer. In FIG. 4A, no crack due to light leakage due to the nanoslit a is confirmed. On the other hand, FIG. 4B shows a case in which three cracks of light leakage due to the nanoslit a occur in the absorption axis direction of the polarizer due to heating. In FIG. 4, the sample in which the nanoslit was generated was observed with a differential interference microscope. When photographing the sample, a sample without nanoslits was set below the sample with nanoslits (transmission light source side) so as to be in a crossed Nicols state, and observation was performed with transmitted light. .

<Measurement of weight change rate>
After 50 mg of the prepared pressure-sensitive adhesive layer was placed in a sample basket and set on an apparatus balance, water absorption / desorption measurement was performed using a water absorption / desorption measuring device (IGA-Sorp, manufactured by Hidden). The measurement conditions are as follows. The weight change rate was calculated by substituting W ₀ and W ₁ obtained in the measurement into the following equation (1).
Drying (pretreatment for removing water in the adhesive layer): (100 ° C., Dry, 1 hour)
Program: (23 ° C., Dry, 2 hours) (W ₀ ) → (23 ° C., 55% RH, 5 hours) → (60 ° C., 95% RH, 5 hours) (W ₁ ) → (23 ° C., 55% RH, 5 hours)
Measurement mode: Sequence
Weight change rate (%) = {(W ₁ −W ₀ ) / W ₀ } × 100 (1)
W ₀ = weight of the pressure-sensitive adhesive layer after drying the pressure-sensitive adhesive layer at 23 ° C. for 2 hours W ₁ = standing of the pressure-sensitive adhesive layer after the drying at 23 ° C. and 55% RH for 5 hours, and further at 60 ° C. 95% Weight of adhesive layer after leaving at RH for 5 hours

<Measurement of adhesive strength, evaluation of peeling>
The prepared piece-protected polarizing film with an adhesive layer and both protective polarizing films with an adhesive layer were used as samples.
The sample was affixed to the surface of the non-alkali glass plate using a laminator, and then autoclaved at 50 ° C. and 5 atm for 15 minutes to completely adhere. Then, using a rework apparatus, the adhesive force P ₀ (N / 25 mm) when the polarizing film was peeled off from the surface of the alkali-free glass plate under the conditions of a peeling temperature of 23 ° C., a peeling speed of 300 mm / min, and a peeling angle of 90 °. It was measured.
The sample was attached to the surface of an alkali-free glass plate using a laminator, and then autoclaved at 50 ° C. and 5 atm for 15 minutes to completely adhere to each other to obtain a laminate. Then, the obtained laminate was immersed in water at 23 ° C. for 2 hours, and the laminate was taken out of the water. Then, using a rework apparatus, the adhesive force P ₁ (N / 25 mm) when the polarizing film was peeled from the surface of the alkali-free glass plate under the conditions of a peeling temperature of 23 ° C., a peeling speed of 300 mm / min, and a peeling angle of 90 °. It was measured.
The obtained laminate was immersed in water at 23 ° C. for 5 hours, and the laminate was taken out of the water. Then, using a reworking apparatus, the adhesive force P ₂ (N / 25 mm) when the polarizing film was peeled from the surface of the alkali-free glass plate at a peeling temperature of 23 ° C., a peeling speed of 300 mm / min, and a peeling angle of 90 ° was used. It was measured.
Further, the obtained laminate was immersed in water at 23 ° C. for 500 hours, and the laminate was taken out of the water. Thereafter, the presence or absence of peeling of the polarizing film was visually observed and evaluated according to the following criteria.
A: No peeling was observed.
：: Wrinkles were observed at the end of the polarizing film.
X: Clear peeling was observed.

<Evaluation of durability>
Separate the separator films of the protective film with adhesive layer and the protective polarizing film with adhesive layer (15 inches) and use a laminator on 0.7 mm thick non-alkali glass (EG-XG, manufactured by Corning Incorporated) using a laminator. Affixed. Then, autoclave treatment was performed at 50 ° C. and 0.5 MPa for 15 minutes to completely adhere the polarizing film to the non-acrylic glass. Next, this was put under the conditions of a heating oven (heating) at 80 ° C. and a thermo-hygrostat (humidification) at 60 ° C./90% RH, respectively, and the presence or absence of peeling of the polarizing plate after 500 hours was determined as follows. Evaluation was based on criteria.
A: No peeling was observed.
：: Peeling was observed to the extent that it could not be confirmed visually.
Δ: Small peeling that can be visually confirmed was observed.
X: Clear peeling was observed.

<Evaluation of conductive stability>
After peeling off the separator film of the one-sided protective polarizing film with an adhesive layer and the two protective polarizing films with an adhesive layer, the surface resistance value (Ω / □) of the adhesive surface was measured using MCP-HT450 manufactured by Mitsubishi Chemical Analytech. It was measured. Also, after storing the polarizing film in a humidified environment of 60 ° C./90% RH for 500 hours, the surface resistance of the pressure-sensitive adhesive surface was measured in the same manner as described above. The rate of change (%) of the surface resistance value was calculated by the following formula and evaluated according to the following criteria.
Rate of change ΔR (%) = (surface resistance value after storage) × 100 / (surface resistance value before storage)
(Evaluation criteria)
〇: 0 ≦ ΔR <500
Δ: 500 ≦ ΔR <700
×: 700 ≦ ΔR

The piece-protecting polarizing film with the pressure-sensitive adhesive layer of the present invention is used alone or as an optical film obtained by laminating the same, for an image display device such as a liquid crystal display (LCD) and an organic EL display.

DESCRIPTION OF SYMBOLS 1 Polarizer 2 Protective film 3 Adhesive layer etc. 4

Adhesive layer

5, 5a,

5b Separator

6, 6a, 6b Surface protective film 10 Protective polarizing film 11 Protective

polarizing film

20a, 20b with adhesive layer With adhesive layer One-sided protective film roll
21a, 21b Single-sided protective polarizing film with adhesive layer (with surface protective film)
100

Continuous manufacturing system

101a, 101b for image display device Polarizing

film supply unit

151a, 151b

Feeding unit

152a, 152b

Cutting unit

153a, 153b

Peeling unit

154a, 154b

Winding unit

201a, 201b Laminating unit 300 Rearrangement unit P Image display panel X Image display panel transport section

Claims

One-sided protective polarizing film having a protective film only on one side of the polarizer and an adhesive layer with an adhesive layer having an adhesive layer directly or through a coating layer on the polarizer side of the one-sided protective polarizing film,
The pressure-sensitive adhesive layer contains a (meth) acrylic polymer as a base polymer,
The pressure-sensitive adhesive layer has a weight change rate calculated by the following formula (1) of 1.1% or more,
The pressure-sensitive adhesive layer has a pressure-sensitive adhesive force P 0 of 10 N / 25 mm or less under the following conditions, and a pressure-sensitive adhesive force P 1 of 1.6 N / 25 mm or more under the following conditions. the film.

Weight change rate (%) = {(W 1 −W 0 ) / W 0 } × 100 (1)
W 0 = weight of the pressure-sensitive adhesive layer after drying the pressure-sensitive adhesive layer at 23 ° C. for 2 hours W 1 = standing of the pressure-sensitive adhesive layer after the drying at 23 ° C. and 55% RH for 5 hours, and further at 60 ° C. 95% Weight of adhesive layer after leaving at RH for 5 hours
Adhesive force P 0 : The pressure-sensitive adhesive layer of the piece-protected polarizing film with the pressure-sensitive adhesive layer was stuck on the surface of an alkali-free glass, and subjected to an autoclave treatment at 50 ° C. and 0.5 atm for 15 minutes. Adhesive force when peeling the pressure-sensitive adhesive layer from the surface of the alkali-free glass under the conditions of a peeling speed of 300 mm / min and a peeling angle of 90 degrees. Adhesive force P 1 : No adhesive layer of the above-mentioned piece-protected polarizing film with an adhesive layer. A laminate obtained by attaching the laminate to the surface of an alkali glass and then performing an autoclave treatment at 50 ° C. and 0.5 atm for 15 minutes is immersed in water at 23 ° C. for 2 hours. Adhesive force when the pressure-sensitive adhesive layer is peeled off from the alkali-free glass surface under the conditions of a temperature of 23 ° C., a peeling speed of 300 mm / min, and a peeling angle of 90 °.
The (meth) acrylic polymer, as a monomer unit,
Alkyl (meth) acrylate (A) having a homopolymer having a glass transition temperature of less than 0 ° C. is 50% by weight or more, and alkyl (meth) acrylate (b1) and a homopolymer having a homopolymer having a glass transition temperature of 0 ° C. or more Having a glass transition temperature of 0 ° C. or higher and at least one high Tg monomer (B) selected from the group consisting of (meth) acryloyl group-containing monomers (b2) having a heterocyclic ring in an amount of 0.1 to 20% by weight. 2. The piece-protecting polarizing film with an adhesive layer according to claim 1.
The (meth) acryl-based polymer is, as a monomer unit, at least one selected from the group consisting of a nitrogen-containing monomer, a carboxyl group-containing monomer, a hydroxyl group-containing monomer, and an aromatic group-containing monomer; The one-sided protective polarizing film provided with an adhesive layer according to claim 2, comprising a polar monomer other than the acryloyl group-containing monomer (b2).
The piece-protecting polarizing film with an adhesive layer according to claim 3, wherein the nitrogen-containing monomer is a vinyl monomer having a lactam ring.
The one-sided protective polarizing film with an adhesive layer according to claim 4, wherein the vinyl monomer having a lactam ring is a vinylpyrrolidone monomer.
The one-sided protective polarizing film with an adhesive layer according to claim 5, wherein the vinylpyrrolidone-based monomer is N-vinylpyrrolidone.
The one-sided protective polarizing film with an adhesive layer according to any one of claims 3 to 6, wherein the (meth) acrylic polymer contains 0.1 to 5% by weight of the nitrogen-containing monomer as a monomer unit.
8. The piece-protecting polarizing film with an adhesive layer according to claim 3, wherein the (meth) acrylic polymer contains the carboxyl group-containing monomer as a monomer unit in an amount of 0.01 to 3% by weight.
片 The one-sided protective polarizing film with an adhesive layer according to any one of claims 3 to 8, wherein the (meth) acrylic polymer contains 0.01 to 1% by weight of the hydroxyl group-containing monomer as a monomer unit.
The one-sided protective polarizing film with an adhesive layer according to any one of claims 3 to 9, wherein the (meth) acrylic polymer contains 1 to 20% by weight of the aromatic group-containing monomer as a monomer unit.
The one-sided protective polarizing film with an adhesive layer according to any one of claims 1 to 10, wherein the (meth) acrylic polymer has a weight average molecular weight of 1.5 million or less.
The pressure-sensitive adhesive layer contains a silane coupling agent having at least one functional group selected from the group consisting of an epoxy group, an isocyanate group, a mercapto group, an acid anhydride group, and an amino group. A piece-protecting polarizing film provided with an adhesive layer according to any one of the above.
The one-sided protective polarizing film with an adhesive layer according to claim 12, wherein the content of the silane coupling agent is 0.01 to 3 parts by weight based on 100 parts by weight of the (meth) acrylic polymer.
片 The piece-protecting polarizing film with an adhesive layer according to any one of claims 1 to 13, wherein the polarizer has a thickness of 12 μm or less.
The polarizer contains a polyvinyl alcohol-based resin, and has an optical property represented by a single transmittance T and a degree of polarization P of the following formula: P>-(10 0.929T-42.4 -1) × 100 (However, T <42.3) or
15. The piece-protecting polarizing film with an adhesive layer according to claim 1, which is configured to satisfy a condition of P ≧ 99.9 (where T ≧ 42.3).
The one-sided protective polarizing film with an adhesive layer according to any one of claims 1 to 15, wherein the polarizer contains boric acid in an amount of 25% by weight or less based on the total amount of the polarizer.
17. The piece-protected polarizing film with an adhesive layer according to claim 1, wherein a separator is provided on the adhesive layer.
The piece-protected polarizing film provided with an adhesive layer according to claim 17, which is a wound body.
An image display device comprising the piece-protected polarizing film provided with the pressure-sensitive adhesive layer according to any one of claims 1 to 16.
19. The image display panel, wherein the piece-protecting piece of polarizing film with an adhesive layer is unwound from the wound body of the piece-protecting piece of polarizing film with an adhesive layer according to claim 18 and is conveyed by the separator, via the adhesive layer. A continuous manufacturing method for an image display device, comprising a step of continuously bonding the image display device to a surface of the image display device.