JP6837282B2 - Optical film with adhesive layer - Google Patents

Description

The present invention relates to an optical film with an adhesive layer, and more particularly to an optical film with an adhesive layer used for bonding an optical film such as a polarizing plate or a composite polarizing plate to a liquid crystal cell or the like.

In recent years, as a display panel of various electronic devices, a touch panel that also serves as a display device and an input means is often used. The types of touch panels are mainly resistance film type, capacitance type, optical type and ultrasonic type, resistance film type includes analog resistance film type and matrix resistance film type, and capacitance type has surface. There are types and projection types.

Many touch panels in mobile electronic devices such as smartphones and tablet terminals, which have been attracting attention recently, are of the projection type capacitance type. As a projection type capacitive touch panel in such a mobile electronic device, for example, a liquid crystal display (LCD), an adhesive layer, a transparent conductive film (tin-doped indium oxide: ITO), a glass substrate, and a transparent conductive film (in order from the bottom). It has been proposed that a protective plate such as ITO) and tempered glass is laminated.

A liquid crystal cell is generally used as an optical component constituting the liquid crystal display device. The liquid crystal cell is generally arranged with the alignment layer of the two transparent electrode substrates on which the alignment layer is formed inside at a predetermined interval by a spacer, and the periphery thereof is sealed to form the two transparent electrode substrates. A liquid crystal material is sandwiched between them. Usually, a polarizing plate and a composite polarizing plate having a retardation plate are adhered to the outside of the two transparent electrode substrates in the liquid crystal cell, respectively, via an adhesive.

As an optical pressure-sensitive adhesive, for example, those shown in Patent Document 1 are known. This pressure-sensitive adhesive contains 0.2 to 20 parts by mass of a carboxyl group-containing monomer as a copolymerization component with respect to 100 parts by mass of an alkyl (meth) acrylate having an alkyl group having 4 to 14 carbon atoms as a monomer unit. 0.02 to 2 parts by mass of peroxide as a cross-linking agent and 0.005 to 5 parts by mass of an epoxy-based cross-linking agent with respect to 100 parts by mass of the (meth) acrylic polymer and the (meth) acrylic polymer. Contains.

Japanese Unexamined Patent Publication No. 2009-242786

Here, with the recent demand for thinner mobile electronic devices, it is required to thin optical films such as polarizing plates. However, the thin-film polarizing plate has a high shrinkage rate due to heat or the like, and with conventional adhesives such as Patent Document 1, the display panel is warped, or floats or peels off under high temperature conditions or moist heat conditions. It ends up. Further, it has been pointed out that there is a problem that light leakage (so-called heat unevenness) occurs due to the deviation of the optical axis of the optical film due to the stress at the time of heat shrinkage of the optical film.

Further, when the thinning of the optical film is prioritized, the adhesion to the pressure-sensitive adhesive deteriorates, and the conventional pressure-sensitive adhesive such as Patent Document 1 has insufficient adhesion at the interface between the optical film and the pressure-sensitive adhesive. , Durability tends to be further deteriorated.

On the other hand, since the release sheet laminated on the pressure-sensitive adhesive layer or the optical film such as a polarizing plate or a composite polarizing plate is usually made of a plastic material, it has high electrical insulation and is charged with static electricity when the release sheet is peeled off. Is likely to occur. If a polarizing plate, a composite polarizing plate, or the like is attached to a liquid crystal cell while the static electricity generated in this way remains, the orientation of the liquid crystal molecules may be disturbed, and the presence of static electricity causes dust and dirt. Causes problems such as suction. In order to solve such a problem, it is conceivable to impart antistatic properties to the pressure-sensitive adhesive layer. However, it is required that the durability is not deteriorated and the display panel is not warped.

The present invention has been made in view of such an actual situation, and even when a thinned optical film is used, the present invention is excellent in durability, the display panel is less likely to warp, and heat unevenness is less likely to occur. Furthermore, it is an object of the present invention to provide an optical film with an adhesive layer having excellent antistatic properties.

In order to achieve the above object, the present invention is an optical film with an adhesive layer including an optical film and an adhesive layer laminated on at least one side of the optical film, and the adhesive in the optical film. The surface in contact with the layer is made of an acrylic resin, and the pressure-sensitive adhesive layer contains an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2), and an oxyalkylene group as monomer units constituting the polymer. A pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive obtained from a pressure-sensitive adhesive composition containing a (meth) acrylic acid ester copolymer (A) containing a monomer (a3) and a cross-linking agent (B). An optical film with an adhesive is provided (Invention 1).

According to the above invention (Invention 1), even when the surface of the optical film in contact with the pressure-sensitive adhesive layer is made of an acrylic resin and the optical film is thinned, the (meth) acrylic acid ester is mainly used. By composing the copolymer (A) having the above composition, when it is used for a display panel, it is excellent in durability, the display panel is less likely to warp, heat unevenness is less likely to occur, and further, antistatic property is also excellent.

In the above invention (Invention 1), it is preferable that the adhesive composition further contains an antistatic agent (C) (Invention 2).

In the above inventions (Inventions 1 and 2), it is preferable that the outermost layer of the optical film in contact with the pressure-sensitive adhesive layer is an acrylic resin layer formed through extrusion molding (Invention 3).

In the above invention (Invention 3), it is preferable that the optical film includes at least a retardation plate having the acrylic resin layer and a retardation expression layer (Invention 4).

In the above invention (Invention 4), it is preferable that the retardation expression layer is made of a styrene resin (Invention 5).

In the above inventions (Inventions 4 and 5), the retardation plate may have a second acrylic resin layer on the surface opposite to the surface of the retardation expression layer on the acrylic resin layer side. Preferred (Invention 6).

In the above inventions (Inventions 4 to 6), it is preferable that a second retardation plate is further laminated on the surface side of the retardation plate opposite to the surface on the pressure-sensitive adhesive layer side (Invention 7). ..

In the above invention (Invention 7), it is preferable that the second retardation plate is made of a cycloolefin resin (Invention 8).

In the above inventions (Inventions 7 and 8), it is preferable that a polarizing plate is further laminated on the surface side of the second retardation plate opposite to the surface on the retardation plate side (Invention 9). ..

In the above inventions (Inventions 1 to 9), the (meth) acrylic acid ester copolymer (A) further contains a hydroxyl group-containing monomer (a4) as a monomer unit constituting the polymer, and has a hydroxyl value. It is preferably 5 mgKOH / g or more and 20 mgKOH / g or less (Invention 10).

According to the optical film with an adhesive layer according to the present invention, even when the optical film is thinned, it has excellent durability, the display panel is less likely to warp, heat unevenness is less likely to occur, and further, antistatic. Excellent in sex.

It is sectional drawing of the optical film with an adhesive layer which concerns on one Embodiment of this invention. It is sectional drawing of the optical film with an adhesive layer which concerns on another embodiment of this invention. It is sectional drawing which shows the structural example of the retardation plate. It is a figure (color) which shows the evaluation standard of the heat resistance unevenness test (visual) in the optical film with an adhesive layer.

Hereinafter, embodiments of the present invention will be described.
The optical film with an adhesive layer according to the present embodiment includes an optical film and an adhesive layer laminated on at least one side of the optical film. The surface of the optical film in contact with the pressure-sensitive adhesive layer is made of an acrylic resin, and the pressure-sensitive adhesive layer is composed of an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2) and, as monomer units constituting the polymer. An adhesive composition containing a (meth) acrylic acid ester copolymer (A) containing an oxyalkylene group-containing monomer (a3) and a cross-linking agent (B) (hereinafter, may be referred to as "adhesive composition P"). It consists of an adhesive obtained from). The tacky composition P preferably further contains an antistatic agent (C) and / or a silane coupling agent (D). In addition, in this specification, (meth) acrylic acid ester means both acrylic acid ester and methacrylic acid ester. The same applies to other similar terms.

The optical film with an adhesive layer has excellent durability when applied to a display panel, even when the optical film used is thinner than that of a conventional product, and is used under high temperature conditions, moist heat conditions, or the like. Even under heat shock, the occurrence of floating and peeling is suppressed. Further, the display panel using the above-mentioned adhesive is less likely to warp even under high temperature conditions, is less likely to cause heat unevenness, and is also excellent in antistatic property.

Here, the optical film includes a function expression layer that exhibits optical performance such as polarization performance and retardation performance, and a protective layer (for morphology retention) for protecting the function expression layer and maintaining morphological stability. Often consists of. The present inventors have found that by using an acrylic resin for the protective layer, the optical performance of the function-expressing layer is not deteriorated and the thin film can be formed. However, in the conventional optical film with an adhesive layer, when an acrylic resin is used for the protective layer to form a thin film, it is subjected to durable conditions (high temperature conditions, wet heat conditions or heat shock as exemplified in the test examples described later). In addition to the following, it also includes under high temperature environment and moist heat environment during actual use. Unless otherwise specified, the same applies hereinafter.) In addition to insufficient morphological retention, it also adheres to the adhesive layer. It will be insufficient. As a result, the optical film with an adhesive layer using the optical film was not satisfactory in both durability and heat resistance unevenness. Furthermore, the warp tends to be severe under high temperature conditions. On the other hand, in the optical film with an adhesive layer according to the present embodiment, the residual stress of the adhesive layer due to the shrinkage of the optical film under durable conditions is increased, and the stress relaxation property of the adhesive layer is enhanced by the composition described above. It can be resolved.

[Adhesive layer]
(1) (Meta) acrylic acid ester copolymer (A)
The (meth) acrylic acid ester copolymer (A) in the present embodiment contains an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2), and an oxyalkylene group as the monomer units constituting the polymer. Contains the monomer (a3). By containing the alicyclic structure-containing monomer (a1) and the aromatic ring-containing monomer (a2), the obtained pressure-sensitive adhesive can have appropriate cohesive force and stress relaxation property, and adheres to the acrylic resin. Since it has high properties, it can exhibit excellent durability, warpage suppression property, and heat unevenness when used for a display panel.

Further, the (meth) acrylic acid ester copolymer (A) contains an oxyalkylene group-containing monomer (a3) as a monomer unit constituting the polymer, whereby the (meth) acrylic acid ester copolymer (meth) acrylic acid ester copolymer ( A) As a result, the hydrophilicity of the obtained pressure-sensitive adhesive is improved, and the pressure-sensitive adhesive layer exhibits excellent antistatic properties. Therefore, static electricity is less likely to be generated when the release sheet is peeled from the pressure-sensitive adhesive layer of the optical film with the pressure-sensitive adhesive layer according to the present embodiment. Therefore, for example, when an optical film with an adhesive layer from which a release sheet has been peeled off is attached to a liquid crystal cell, it is possible to prevent the liquid crystal molecules from being disturbed in orientation, and dust and dirt are attracted by static electricity. It can also be suppressed.

Here, the antistatic agent (C) described later is generally a low molecular weight component, and if the amount added is too large, the cohesive force of the obtained adhesive tends to decrease and the durability tends to deteriorate. .. In order to improve the cohesive force of the pressure-sensitive adhesive, the amount of the cross-linking agent (B) added may be increased, but this may cause the pressure-sensitive adhesive layer to become too hard and the resulting display panel to be easily warped. There is. Further, if the amount of the antistatic agent (C) added is too large, the adhesiveness of the pressure-sensitive adhesive layer to the acrylic resin may decrease. On the other hand, the (meth) acrylic acid ester copolymer (A) contains the oxyalkylene group-containing monomer (a3) as the monomer unit constituting the polymer, so that the antistatic agent (C) is added. By reducing the amount, the above-mentioned problems can be prevented, and excellent antistatic properties can be obtained.

From another point of view, the optical film with an adhesive layer according to the present embodiment has a structure in which an adhesive layer made of an acrylic adhesive is laminated on a protective layer made of an acrylic resin. That is, since the protective layer and the pressure-sensitive adhesive layer are made of the same material, migration of low molecular weight components such as the antistatic agent (C) from the pressure-sensitive adhesive layer to the surface of the protective layer is likely to occur, and as a result, both layers are in close contact with each other. There is concern about the problem of worsening sex. On the other hand, in the pressure-sensitive adhesive layer of the present embodiment, it is presumed that the oxyalkylene group derived from the above-mentioned oxyalkylene group-containing monomer (a3) chelately traps the antistatic agent (C), and the pressure-sensitive adhesive layer. It is possible to effectively prevent the transfer of the antistatic agent (C) and the like from the to the protective layer.

The (meth) acrylic acid ester copolymer (A) contains the above-mentioned alicyclic structure-containing monomer (a1), aromatic ring-containing monomer (a2), and oxyalkylene group-containing monomer (a1) as a monomer unit constituting the polymer. In addition to a3), it is preferable to contain a hydroxyl group-containing monomer (a4), and it is particularly preferable to contain a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms. Further, if desired, other monomers may be contained.

Here, the hydroxyl value of the (meth) acrylic acid ester copolymer (A) is preferably 5 mgKOH / g or more, particularly preferably 8 mgKOH / g or more, and further 10 mgKOH / g or more. Is preferable. When the hydroxyl value of the (meth) acrylic acid ester copolymer (A) is 5 mgKOH / g or more, a cross-linking point can be secured and the cohesive force can be maintained high, and the obtained adhesive has excellent durability. It can be effectively demonstrated. The hydroxyl value of the (meth) acrylic acid ester copolymer (A) is preferably 20 mgKOH / g or less, particularly preferably 18 mgKOH / g or less, and further preferably 16 mgKOH / g or less. preferable. When the hydroxyl value of the (meth) acrylic acid ester copolymer (A) is 20 mgKOH / g or less, it is possible to prevent the number of cross-linking points from becoming too large, the resulting adhesive becomes flexible, and excellent stress relaxation property is obtained. As a result, excellent warpage suppression and heat unevenness can be effectively exhibited.

The acid value of the (meth) acrylic acid ester copolymer (A) is preferably 5 mgKOH / g or less, particularly preferably 2 mgKOH / g or less, and further preferably 1 mgKOH / g or less. preferable. When the acid value of the (meth) acrylic acid ester copolymer (A) is 5 mgKOH / g or less, the adhesive is applied to a transparent conductive film such as tin-doped indium oxide (ITO), which causes problems due to the acid. Even in the case of a metal film or the like, those problems caused by acid can be suppressed. In particular, when the object to be attached is a transparent conductive film, it is possible to prevent the transparent conductive film from being corroded or the resistance value of the transparent conductive film from being changed. The lower limit of the acid value of the (meth) acrylic acid ester copolymer (A) is preferably as small as possible, and therefore 0 mgKOH / g is particularly preferable.

Here, the hydroxyl value and the acid value in the present specification are basically theoretical values derived from the blending ratio of the (meth) acrylic acid ester copolymer (A), and if the theoretical values cannot be derived, the theoretical values can be derived. The value is measured based on JIS K0070.

The (meth) acrylic acid ester copolymer (A) contains a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms as a monomer unit constituting the polymer, and thus has preferable adhesiveness. Can be expressed. Examples of the (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms include methyl (meth) acrylic acid, ethyl (meth) acrylic acid, propyl (meth) acrylic acid, and n- (meth) acrylic acid. Butyl, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-decyl (meth) acrylate, (meth) acrylate Examples thereof include n-dodecyl, myristyl (meth) acrylate, palmityl (meth) acrylate, and stearyl (meth) acrylate. Among them, (meth) acrylic acid ester having 1 to 8 carbon atoms of the alkyl group is preferable, and n-butyl (meth) acrylate or 2-ethylhexyl (meth) acrylate is particularly preferable from the viewpoint of further improving the adhesiveness. .. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester copolymer (A) may contain 0% by mass or more of a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms as a monomer unit constituting the polymer. Preferably, from the viewpoint of imparting adhesiveness by the monomer unit, it is particularly preferable to contain 30% by mass or more, and further preferably 45% by mass or more. The (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms of the alkyl group is preferably contained in an amount of 90% by mass or less, particularly preferably 80% by mass or less, and further preferably 70% by mass or less. .. By setting the content of the (meth) acrylic acid alkyl ester to 90% by mass or less, a desired amount of other monomer components can be introduced into the (meth) acrylic acid ester copolymer (A).

The carbon ring having an alicyclic structure in the alicyclic structure-containing monomer (a1) may have a saturated structure or may have an unsaturated bond as a part. Further, the alicyclic structure may be a monocyclic alicyclic structure or a polycyclic alicyclic structure such as two rings or three rings. From the viewpoint of making the distance between the obtained (meth) acrylic acid ester copolymers (A) appropriate and imparting stress relaxation property to the pressure-sensitive adhesive, the alicyclic structure is a polycyclic alicyclic structure. Polycyclic structure) is preferable. Further, in consideration of the compatibility between the (meth) acrylic acid ester copolymer (A) and other components, the polycyclic structure is particularly preferably bicyclic to tetracyclic. Further, from the viewpoint of imparting stress relaxation property as described above, the number of carbon atoms in the alicyclic structure (referring to the total number of carbon atoms in the portion forming the ring, and when a plurality of rings exist independently) , The total number of carbon atoms) is usually preferably 5 or more, and particularly preferably 7 or more. On the other hand, the upper limit of the number of carbon atoms in the alicyclic structure is not particularly limited, but from the viewpoint of compatibility as described above, it is preferably 15 or less, and particularly preferably 10 or less.

Examples of the alicyclic structure include a cyclohexyl skeleton, a dicyclopentadiene skeleton, an adamantan skeleton, an isobornyl skeleton, and a cycloalcan skeleton (cycloheptane skeleton, cyclooctane skeleton, cyclononan skeleton, cyclodecane skeleton, cycloundecane skeleton, cyclododecane skeleton, etc.). , Cycloalkene skeleton (cycloheptene skeleton, cyclooctene skeleton, etc.), norbornen skeleton, norbornadien skeleton, Cuban skeleton, Basquetan skeleton, Hausan skeleton, Spiro skeleton, etc. Those containing a dicyclopentadiene skeleton (carbon number of alicyclic structure: 10), adamantan skeleton (carbon number of alicyclic structure: 10) or isobornyl skeleton (carbon number of alicyclic structure: 7) are preferable, and particularly Those containing an isobornyl skeleton are preferable.

As the alicyclic structure-containing monomer (a1), a (meth) acrylic acid ester monomer containing the above skeleton is preferable, and specifically, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, and the like. Examples thereof include adamantyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, etc., among which they exhibit more excellent durability. Dicyclopentanyl acrylate, adamantyl (meth) acrylate or isobornyl (meth) acrylate are preferred, and isobornyl (meth) acrylate is particularly preferred. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The (meth) acrylic acid ester copolymer (A) is an alicyclic type as a monomer unit constituting the polymer from the viewpoint that the obtained pressure-sensitive adhesive exhibits excellent durability, warpage suppression property and heat resistance unevenness. It is preferable that the structure-containing monomer (a1) is contained in an amount of 1% by mass or more and 20% by mass or less. Further, in addition to the above viewpoints, from the viewpoint that the obtained pressure-sensitive adhesive exhibits excellent reworkability, it is more preferable to contain the alicyclic structure-containing monomer (a1) in an amount of 2% by mass or more, and 3% by mass or more. Is particularly preferred. From the same viewpoint, the alicyclic structure-containing monomer (a1) is more preferably contained in an amount of 15% by mass or less, and particularly preferably contained in an amount of 9% by mass or less.

As the aromatic ring-containing monomer (a2), a (meth) acrylic acid ester having an aromatic ring is preferable. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, a biphenyl ring, a fluorene ring and the like, and a benzene ring is preferable.

Examples of the aromatic ring-containing monomer (a2) include phenyl (meth) acrylate, 2-phenylethyl (meth) acrylate, benzyl (meth) acrylate, naphthyl (meth) acrylate, and phenoxyethyl (meth) acrylate. , (Meta) phenoxybutyl acrylate, ethoxylated o-phenylphenol acrylate, phenoxydiethylene glycol (meth) acrylate and the like, and among them, 2-phenylethyl (meth) acrylate is preferable from the viewpoint of improving cohesiveness. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester copolymer (A) preferably contains 1% by mass or more of the aromatic ring-containing monomer (a2) as a monomer unit constituting the polymer, and particularly contains 3% by mass or more. Is preferable, and more preferably, it is contained in an amount of 12% by mass or more. Further, the aromatic ring-containing monomer (a2) is preferably contained in an amount of 30% by mass or less, particularly preferably 25% by mass or less, and further preferably 22% by mass or less. When the content of the aromatic ring-containing monomer (a2) is in the above range, the obtained pressure-sensitive adhesive can exhibit excellent durability, warpage suppression property, and heat resistance unevenness.

The oxyalkylene group-containing monomer (a3) refers to a monomer having at least one alkylene oxide unit and not containing an alicyclic structure and an aromatic ring. Examples of the oxyalkylene group-containing monomer (a3) include 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxypropyl (meth) acrylate, and 3-methoxypropyl (meth) acrylate. Preferred examples include (meth) acrylic acid alkoxy esters such as methoxypropyl, 2-methoxybutyl (meth) acrylate, and 4-methoxybutyl (meth) acrylate. Further, a (meth) acrylic acid alkoxy ester having a polyethylene glycol chain having a terminal alkoxy group or a polyalkylene glycol chain such as a polypropylene glycol chain can also be preferably mentioned. Among these, 2-methoxyethyl (meth) acrylate is particularly preferable from the viewpoint of chelating the antistatic agent (C) and imparting adhesiveness. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester copolymer (A) preferably contains an oxyalkylene group-containing monomer (a3) in an amount of 0.5% by mass or more, particularly 1% by mass or more, as a monomer unit constituting the polymer. It is preferably contained, more preferably 5% by mass or more, and most preferably 12% by mass or more. Further, the oxyalkylene group-containing monomer (a3) is preferably contained in an amount of 90% by mass or less, particularly preferably 50% by mass or less, and further preferably 25% by mass or less. When the content of the oxyalkylene group-containing monomer (a3) is within the above range, the obtained adhesive exhibits excellent antistatic properties while maintaining excellent durability, warpage suppression and heat unevenness. can do.

The (meth) acrylic acid ester copolymer (A) preferably contains a hydroxyl group-containing monomer (a4) as a monomer unit constituting the polymer. The hydroxyl group exhibits good reactivity with the cross-linking agent (B), and the reaction causes the (meth) acrylic acid ester copolymer (A) to be cross-linked by the cross-linking agent (B). Due to this crosslinked structure, the obtained adhesive has excellent durability.

Examples of the hydroxyl group-containing monomer (a4) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate. , (Meta) acrylic acid hydroxyalkyl esters such as (meth) acrylic acid 3-hydroxybutyl, (meth) acrylic acid 4-hydroxybutyl, etc., among others, from the viewpoint of reactivity with the cross-linking agent (B) ( 2-Hydroxyethyl acrylate or 4-hydroxybutyl (meth) acrylate is preferable, and 2-hydroxyethyl (meth) acrylate is particularly preferable. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester copolymer (A) preferably contains a hydroxyl group-containing monomer (a4) in an amount of 0.5% by mass or more, particularly 1% by mass or more, as a monomer unit constituting the polymer. It is preferably contained in an amount of 2% by mass or more. Further, the hydroxyl group-containing monomer (a4) is preferably contained in an amount of 10% by mass or less, particularly preferably 5% by mass or less, and further preferably 4% by mass or less. When the content of the hydroxyl group-containing monomer (a4) is within the above range, the hydroxyl value of the (meth) acrylic acid ester copolymer (A) is likely to fall within the above range, resulting in excellent durability and warpage suppression. And heat unevenness can be effectively exhibited.

The (meth) acrylic acid ester copolymer (A) preferably does not contain a carboxyl group-containing monomer as a monomer unit constituting the polymer, even if it does, in order to keep the acid value in the above-mentioned range. , 0.5% by mass or less, and particularly preferably 0.1% by mass or less.

The (meth) acrylic acid ester copolymer (A) may contain a monomer other than the above-mentioned monomer as the monomer unit constituting the polymer. As the other monomer, a monomer containing no functional group reactive with the cross-linking agent (B) is preferable so as not to interfere with the reaction between the hydroxyl group of the hydroxyl group-containing monomer (a4) and the cross-linking agent (B). ..

Examples of such other monomers include non-crosslinkable acrylamides such as acrylamide and methacrylamide, and non-crosslinkable acrylamides such as (meth) acrylate N, N-dimethylaminoethyl and (meth) acrylate N, N-dimethylaminopropyl. Examples thereof include (meth) acrylic acid ester having a sex tertiary amino group, vinyl acetate and the like. These may be used alone or in combination of two or more.

The polymerization mode of the (meth) acrylic acid ester copolymer (A) may be a random copolymer or a block copolymer.

The weight average molecular weight of the (meth) acrylic acid ester copolymer (A) is preferably 1.3 million or more, particularly preferably 1.5 million or more, and further preferably 1.6 million or more. When the weight average molecular weight of the (meth) acrylic acid ester copolymer (A) is 1.3 million or more, the durability of the obtained pressure-sensitive adhesive can be satisfactorily ensured. The weight average molecular weight of the (meth) acrylic acid ester copolymer (A) is preferably 3 million or less, particularly preferably 2.5 million or less, and further preferably 1.9 million or less. When the weight average molecular weight of the (meth) acrylic acid ester copolymer (A) is 3 million or less, the stress relaxation property of the obtained pressure-sensitive adhesive is satisfactorily secured, and the warp suppression property and the heat resistance unevenness are effectively exhibited. can do.

Here, the weight average molecular weight in the present specification is a value in terms of standard polystyrene measured by a gel permeation chromatography (GPC) method.

The polymerization mode of the (meth) acrylic acid ester copolymer (A) may be a random copolymer or a block copolymer.

In the adhesive composition P, the (meth) acrylic acid ester copolymer (A) may be used alone or in combination of two or more. Further, the adhesive composition P is a (meth) acrylic acid ester polymer that does not contain an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2), or an oxyalkylene group-containing monomer (a3) as a constituent monomer unit. May be further contained.

(2) Crosslinking agent (B)
The cross-linking agent (B) may be any as long as it reacts with the functional group of the (meth) acrylic acid ester copolymer (A). For example, an isocyanate-based cross-linking agent, an epoxy-based cross-linking agent, an amine-based cross-linking agent, and melamine. Examples include cross-linking agents, aziridine cross-linking agents, hydrazine cross-linking agents, aldehyde-based cross-linking agents, oxazoline-based cross-linking agents, metal alkoxide-based cross-linking agents, metal chelate-based cross-linking agents, metal salt-based cross-linking agents, ammonium salt-based cross-linking agents, etc. Be done.

When the (meth) acrylic acid ester copolymer (A) contains a hydroxyl group-containing monomer (a4) as a monomer unit constituting the polymer, the reactivity with the hydroxyl group derived from the hydroxyl group-containing monomer (a4) is increased. It is preferable to use an excellent isocyanate-based cross-linking agent. The cross-linking agent (B) may be used alone or in combination of two or more.

The isocyanate-based cross-linking agent contains at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanates, and alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate. In addition, these biuret compounds, isocyanate compounds, and adduct compounds, which are reactants with low molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil (collectively, above). It may be referred to as a "modified compound"). Among these, from the viewpoint of the durability of the obtained pressure-sensitive adhesive, a compound having an aromatic ring, that is, an aromatic polyisocyanate or a modified product thereof is preferable, and an organic group (for example, an alkylene chain) is preferably mentioned in the aromatic ring, and the number of carbon atoms is preferable. 1 to 4 alkylene chains are particularly preferable.) Polyisocyanate having an isocyanate group bonded via an isocyanate group or a modified product thereof is particularly preferable. Specifically, xylylene diisocyanate or a modified product thereof is more preferable, and trimethylolpropane-modified xylylene diisocyanate is most preferable. The above-mentioned isocyanate-based cross-linking agent may be used alone or in combination of two or more.

The content of the cross-linking agent (B) in the adhesive composition P is preferably 0.01 part by mass or more with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer (A), and is particularly 0. It is preferably 0.05 parts by mass or more, and more preferably 0.1 parts by mass or more. The content is preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and further preferably 0.4 parts by mass or less. When the content of the cross-linking agent (B) is in the above range, the obtained pressure-sensitive adhesive exhibits good cohesive force and stress relaxation property, and is excellent in durability, warpage suppression property and heat resistance unevenness. ..

(3) Antistatic agent (C)
The adhesive composition P preferably further contains an antistatic agent (C). When the antistatic agent (C) is contained, the pressure-sensitive adhesive (adhesive layer) obtained by interacting with the oxyalkylene group-containing monomer (a3) constituting the (meth) acrylic acid ester copolymer (A) is charged. The preventability becomes better.

The antistatic agent (C) may be any as long as it can impart antistatic properties to the obtained pressure-sensitive adhesive, and examples thereof include ionic compounds and nonionic compounds. Among them, ionic compounds are preferable. .. The ionic compound may be liquid or solid at room temperature, but is preferably solid at room temperature from the viewpoint of easily exhibiting stable antistatic properties even when exposed to durable conditions. .. Here, the ionic compound in the present specification means a compound in which cations and anions are mainly bound by electrostatic attraction.

As the ionic compound, a nitrogen-containing onium salt, a sulfur-containing onium salt, a phosphorus-containing onium salt, an alkali metal salt or an alkaline earth metal salt is preferable, and from the viewpoint that the obtained pressure-sensitive adhesive has excellent durability, the nitrogen-containing onium salt or Alkali metal salts are preferable, and nitrogen-containing onium salts are more preferable. The nitrogen-containing onium salt is preferably an ionic compound composed of a nitrogen-containing heterocyclic cation and its counter anion.

As the nitrogen-containing heterocyclic skeleton of the nitrogen-containing heterocyclic cation, a pyridine ring, a pyrimidine ring, an imidazole ring, a triazole ring, an indole ring and the like are preferable, and a pyridine ring is particularly preferable. Further, as the cation of the alkali metal salt, lithium ion, potassium ion or sodium ion is preferable, and lithium ion or potassium ion is particularly preferable.

On the other hand, as the anion constituting the ionic compound, a halide phosphate anion or a sulfonylimide anion is preferably mentioned. As the halide anion, hexafluorophosphate and the like are preferably mentioned. Further, as the sulfonylimide-based anion, bis (fluoroalkylsulfonyl) imide, bis (fluorosulfonyl) imide and the like are preferably mentioned.

Specific examples of the antistatic agent (C) include N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methylpyridinium hexafluorophosphate, N-octylpyridinium hexafluorophosphate, and N-octyl-4. -Methylpyridinium hexafluorophosphate, N-dodecylpyridinium hexafluorophosphate, N-tetradecylpyridinium hexafluorophosphate, N-hexadecylpyridinium hexafluorophosphate, N-dodecyl-4-methylpyridinium hexafluorophosphate, N-tetradecyl-4 -Methylpyridinium hexafluorophosphate, N-hexadecyl-4-methylpyridinium hexafluorophosphate, N-decylpyridinium bis (fluorosulfonyl) imide, 1-ethylpyridinium bis (fluorosulfonyl) imide, 1-butylpyridinium bis (fluorosulfonyl) Imide, 1-hexylpyridinium bis (fluorosulfonyl) imide, 1-butyl-3-methylpyridinium bis (fluorosulfonyl) imide, 1-butyl-4-methylpyridinium bis (fluorosulfonyl) imide, 1-hexyl-3 -Methylpyridinium bis (fluorosulfonyl) imide, 1-butyl-3,4-dimethylpyridinium bis (fluorosulfonyl) imide, potassium bis (fluorosulfonyl) imide, lithium bis (fluorosulfonyl) imide, potassium bis (fluoromethanesulfonyl) Examples thereof include imide and lithium bis (fluoromethanesulfonyl) imide. Among these, from the viewpoint of compatibility with the (meth) acrylic acid ester copolymer (A), N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methylpyridinium hexafluorophosphate, N- Octyl-4-methylpyridinium hexafluorophosphate, N-decylpyridinium bis (fluorosulfonyl) imide, or potassium bis (fluorosulfonyl) imide are preferred. The above antistatic agent (C) may be used alone or in combination of two or more.

The content of the antistatic agent (C) in the adhesive composition P is preferably 0.1 part by mass or more with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer (A). It is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and most preferably 3.5 parts by mass or more. The content is preferably 15 parts by mass or less, particularly preferably 10 parts by mass or less, and further preferably 5 parts by mass or less. When the content of the antistatic agent (C) is within the above range, the antistatic property can be effectively exhibited, and the deterioration of physical properties such as optical characteristics, durability, and warpage inhibitory property can be prevented. Can be done. In the adhesive composition P, the (meth) acrylic acid ester copolymer (A) contains an oxyalkylene group-containing monomer (a3) as a monomer unit constituting the polymer, whereby an antistatic agent is used. Even if the content of (C) is relatively small as described above, the obtained adhesive exhibits excellent antistatic properties, has high adhesion to acrylic resins, and has durability and warpage suppression properties. It will be excellent.

(4) Silane coupling agent (D)
The adhesive composition P preferably further contains a silane coupling agent (D), and from the viewpoint of imparting excellent durability to the obtained pressure-sensitive adhesive, particularly the epoxy group-containing silane coupling agent (D1) and /. Alternatively, it preferably contains a mercapto group-containing silane coupling agent (D2), and further preferably contains both an epoxy group-containing silane coupling agent (D1) and a mercapto group-containing silane coupling agent (D2).

The epoxy group-containing silane coupling agent (D1) is an organic silicon compound having at least one epoxy group (organic group containing an epoxy group) and at least one alkoxysilyl group in the molecule, and is a pressure-sensitive adhesive component. Those having good compatibility with and having light transmittance, for example, those having substantially transparent are preferable.

Specific examples of the epoxy group-containing silane coupling agent (D1) include 3-glycidoxypropyltrialkoxysilane and 3-glycyl, such as 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane. 3-Glysidoxypropylalkyldialkoxysilanes such as Sidoxypropylmethyldiethoxysilane and 3-glycidoxypropylmethyldimethoxysilane, Methyltri (glycidyl) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane , 2- (3,4-epylcyclohexyl) ethyltrialkoxysilane such as 2- (3,4-epylcyclohexyl) ethyltriethoxysilane and the like. Among them, from the viewpoint of further improving durability, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4 epoxycyclohexyl) ) Ethyltrimethoxysilane is preferable, and 3-glycidoxypropyltrimethoxysilane is particularly preferable. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The mercapto group-containing silane coupling agent (D2) is an organosilicon compound having at least one mercapto group (organic group containing a mercapto group) and at least one alkoxysilyl group in the molecule, and is a pressure-sensitive adhesive component. Those having good compatibility with and having light transmittance, for example, substantially transparent ones are preferable.

Specific examples of the mercapto group-containing silane coupling agent (D2) include mercapto group-containing low molecular weight silane couplings such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane. Agents: Mercapto group-containing silane compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane, and methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyl. Examples thereof include a mercapto group-containing oligomer-type silane coupling agent such as a cocondensate with an alkyl group-containing silane compound such as trimethoxysilane. Among them, a mercapto group-containing oligomer-type silane coupling agent is preferable from the viewpoint of achieving both durability and reworkability, and a cocondensate of a mercapto group-containing silane compound and an alkyl group-containing silane compound is particularly preferable, and further 3- A cocondensate of mercaptopropyltrimethoxysilane and methyltriethoxysilane is preferred. These may be used individually by 1 type, and may be used in combination of 2 or more type.

As the silane coupling agent (D), in addition to the epoxy group-containing silane coupling agent (D1) and the mercapto group-containing silane coupling agent (D2), for example, an acryloyl-based silane coupling agent, if necessary. A hydroxyl group-based silane coupling agent, a carboxyl-based silane coupling agent, an amino-based silane coupling agent, an amide-based silane coupling agent, an isocyanate-based silane coupling agent, or the like may be used in combination.

The total content of the silane coupling agent (D) in the adhesive composition P is preferably 0.01 part by mass or more with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer (A). In particular, it is preferably 0.1 part by mass or more, and further preferably 0.2 part by mass or more. The total content is preferably 5 parts by mass or less, particularly preferably 2 parts by mass or less, and further preferably 1 part by mass or less.

The content of the epoxy group-containing silane coupling agent (D1) in the adhesive composition P is 0.005 part by mass or more with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer (A). It is preferably 0.05 parts by mass or more, and further preferably 0.1 parts by mass or more. The content is preferably 2.5 parts by mass or less, particularly preferably 1 part by mass or less, and further preferably 0.5 parts by mass or less. On the other hand, the content of the mercapto group-containing silane coupling agent (D2) in the adhesive composition P is 0.005 part by mass or more with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer (A). It is preferably 0.05 parts by mass or more, and further preferably 0.1 parts by mass or more. The content is preferably 2.5 parts by mass or less, particularly preferably 1 part by mass or less, and further preferably 0.5 parts by mass or less.

(5) Various Additives The tacky composition P contains various additives usually used for acrylic pressure-sensitive adhesives, for example, dispersants (for example, alkylene glycol dialkyl ethers), tackifiers, and antioxidants, if desired. Agents, UV absorbers, light stabilizers, softeners, fillers, refractive index adjusters and the like can be added. The adhesive composition P represents a mixture of various components remaining in the pressure-sensitive adhesive layer as it is or in a reacted state, and is a component removed in a drying step or the like, for example, polymerization described later. The solvent and the diluting solvent are not included in the adhesive composition P.

(6) Method for Producing Adhesive Composition The adhesive composition P produced a (meth) acrylic acid ester copolymer (A), and the (meth) acrylic acid ester copolymer (A) obtained by producing the adhesive composition P and the (meth) acrylic acid ester copolymer (A). It can be produced by mixing a cross-linking agent (B) and, if desired, an antistatic agent (C), a silane coupling agent (D), an additive and the like.

The (meth) acrylic acid ester copolymer (A) can be produced by polymerizing a mixture of monomer units constituting the polymer by an ordinary radical polymerization method. The polymerization of the (meth) acrylic acid ester copolymer (A) can be carried out by a solution polymerization method or the like using a polymerization initiator, if desired. Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone and the like, and two or more of them may be used in combination.

Examples of the polymerization initiator include azo compounds and organic peroxides, and two or more of them may be used in combination. Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane1-carbonitrile), and 2 , 2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2'-azobis (2-methylpropionate) , 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-hydroxymethylpropionitrile), 2,2'-azobis [2- (2-imidazolin-2-yl)) Propane] and the like.

Examples of the organic peroxide include benzoyl peroxide, t-butylperbenzoate, cumenehydroperoxide, diisopropylperoxydicarbonate, di-n-propylperoxydicarbonate, and di (2-ethoxyethyl) peroxy. Examples thereof include dicarbonate, t-butylperoxyneodecanoate, t-butylperoxyvivarate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide and the like.

In the above polymerization step, the weight average molecular weight of the obtained polymer can be adjusted by adding a chain transfer agent such as 2-mercaptoethanol.

Once the (meth) acrylic acid ester copolymer (A) is obtained, the solution of the (meth) acrylic acid ester copolymer (A) is mixed with a cross-linking agent (B), and if desired, an antistatic agent (C) and silane. By adding the coupling agent (D), the additive, the diluting solvent and the like and mixing them sufficiently, the adhesive composition P (coating solution) diluted with the solvent is obtained.

Examples of the diluting solvent for diluting the adhesive composition P into a coating solution include aliphatic hydrocarbons such as hexane, heptane and cyclohexane, aromatic hydrocarbons such as toluene and xylene, methylene chloride and ethylene chloride. Halogenized hydrocarbons, methanol, ethanol, propanol, butanol, alcohols such as 1-methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, cyclohexanone, esters such as ethyl acetate and butyl acetate, ethyl. A cellosolve-based solvent such as cellosolve is used.

The concentration and viscosity of the coating solution prepared in this manner may be any range as long as it can be coated, and is not particularly limited and can be appropriately selected depending on the situation. For example, the adhesive composition P is diluted so as to have a concentration of 10 to 40% by mass. It should be noted that the addition of a diluting solvent or the like is not a necessary condition when obtaining the coating solution, and the diluting solvent may not be added as long as the adhesive composition P has a coatable viscosity or the like. In this case, the adhesive composition P becomes a coating solution using the polymerization solvent of the (meth) acrylic acid ester copolymer (A) as it is as a diluting solvent.

(7) Adhesive The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer in the present embodiment is obtained from the pressure-sensitive adhesive composition P described above, and specifically, is obtained by cross-linking the pressure-sensitive adhesive composition P. is there. Crosslinking of the adhesive composition P can be performed by heat treatment. In addition, this heat treatment can also serve as a drying treatment when volatilizing the diluting solvent or the like of the adhesive composition P.

When the heat treatment is performed, the heating temperature is preferably 50 to 150 ° C, particularly preferably 70 to 120 ° C. The heating time is preferably 30 seconds to 10 minutes, and particularly preferably 50 seconds to 2 minutes. After the heat treatment, if necessary, a curing period of about 1 to 2 weeks may be provided at room temperature (for example, 23 ° C., 50% RH). When this curing period is required, after the curing period has elapsed, and when the curing period is not required, after the heat treatment is completed, an adhesive layer having predetermined physical properties is formed.

By the above heat treatment (and curing), the (meth) acrylic acid ester copolymer (A) is crosslinked by the cross-linking agent (B) to form a three-dimensional network structure.

The degree of cross-linking of the pressure-sensitive adhesive, that is, the gel fraction is preferably 40% or more, particularly preferably 60% or more, and further preferably 70% or more. When the gel fraction is 40% or more, the durability of the pressure-sensitive adhesive becomes more excellent. The gel fraction is preferably 90% or less, particularly preferably 85% or less, and further preferably 78% or less. When the gel fraction is 90% or less, the stress relaxation property of the pressure-sensitive adhesive becomes better, and the warp suppression property and the heat resistance unevenness become more excellent. The method for measuring the gel fraction of the pressure-sensitive adhesive is as shown in a test example described later.

(8) Physical Properties of Adhesive Layer The thickness of the adhesive layer is preferably 5 μm or more, more preferably 10 μm or more, and further preferably 15 μm or more. The thickness is preferably 100 μm or less, more preferably 60 μm or less, particularly preferably 50 μm or less, and even more preferably 30 μm or less.

The haze value of the pressure-sensitive adhesive layer (value measured according to JIS K7136: 2000) is preferably 2% or less, and particularly preferably 1% or less. When the haze value is 2% or less, the transparency is very high and it is suitable for optical applications.

[Optical film]
The optical film in the present embodiment may be composed of a single layer or a plurality of layers. Examples of the optical film include a polarizer, a polarizing plate, a retardation plate, a composite polarizing plate such as a polarizing plate with a retardation plate, a viewing angle compensation film, a brightness improving film, a contrast improving film, a liquid crystal polymer film, a diffusion film, and a semi. Examples include a transmissive reflective film and a laminate thereof. Among them, the polarizer is easily shrunk, the dimensional change is large, and durability is required. Therefore, the optical film containing the polarizer is suitable as the optical film of the optical film with an adhesive layer according to the present embodiment. In particular, a thin polarizing plate having a thin protective layer and a composite polarizing plate using the polarizing plate tend to shrink due to heat or the like because the protective layer has a weak force to suppress the shrinkage of the polarizer. It is most suitable as an optical film of the optical film with an adhesive layer according to the present embodiment.

Here, the surface of the optical film in contact with the pressure-sensitive adhesive layer is made of an acrylic resin. By using an acrylic resin at the relevant portion of the optical film, it is possible to reduce the film thickness without impairing the predetermined optical performance. When the optical film is composed of a single layer, the optical film is composed of a single layer of acrylic resin. When the optical film is composed of a plurality of layers, the outermost layer in contact with the pressure-sensitive adhesive layer is preferably composed of an acrylic resin layer formed through extrusion molding. The adhesiveness between the acrylic resin and the conventionally known pressure-sensitive adhesive layer was low, and the durability was also low. However, according to the pressure-sensitive adhesive layer in the present embodiment, the adhesive strength is high even for acrylic resins, and the stress relaxation property is also excellent. Therefore, it has excellent durability even under high temperature conditions, moist heat conditions, heat shock, and the like. The "acrylic resin layer formed through extrusion molding" also includes an acrylic resin layer obtained by drawing after extrusion molding.

The optical film in the present embodiment preferably includes at least an acrylic resin layer and a retardation plate having a retardation expression layer, and the retardation expression layer has thinning and retardation expression. From the viewpoint of compatibility, it is preferably made of a styrene resin. Further, it is preferable that the retardation plate has a second acrylic resin layer on the surface side of the retardation expression layer opposite to the surface on the acrylic resin layer side. As described above, by having the acrylic resin layer and the phase difference expressing layer made of the styrene resin, and further by having the second acrylic resin layer, the liquid crystal display device, particularly IPS (In-Place-Switching). ) Mode In the liquid crystal display device, excellent viewing angle compensation performance can be exhibited.

It is preferable that a second retardation plate is further laminated on the surface side of the retardation plate opposite to the surface on the pressure-sensitive adhesive layer side, and the second retardation plate is made of a cycloolefin resin. Is preferable. By having such a second retardation plate, and further by having a second retardation plate made of a cycloolefin resin, the viewing angle compensation performance becomes more excellent.

Further, it is preferable that a polarizing plate is further laminated on the surface side of the second retardation plate opposite to the surface on the retardation plate side. This makes it possible to provide a composite polarizing plate having extremely excellent viewing angle compensation performance.

[Specific example of optical film with adhesive layer]
1. 1. Example of Optical Film as a Polarizing Plate An example of an optical film with an adhesive layer according to this embodiment when the optical film is a polarizing plate will be described with reference to FIG. As shown in FIG. 1, the optical film 10A with an adhesive layer according to the present embodiment has an adhesive layer 1 laminated on one surface (lower surface in FIG. 1) of the polarizing plate 2A and the polarizing plate 2A. It is configured with and. Although not shown, a release sheet may be laminated on the surface of the pressure-sensitive adhesive layer 1 opposite to the polarizing plate 2A side until the optical film 10A with the pressure-sensitive adhesive layer is used.

The pressure-sensitive adhesive layer 1 is made of a pressure-sensitive adhesive obtained from the above-mentioned pressure-sensitive adhesive composition P.

The polarizing plate 2A in the present embodiment includes a polarizer 21, a first protective layer 22 laminated on one surface of the polarizer 21 (upper surface in FIG. 1), and the other surface of the polarizer 21 (FIG. 1). In No. 1, a second protective layer 23 laminated on the lower surface) is provided. Although not shown, an adhesive layer may be interposed between the polarizer 21 and the first protective layer 22 and / or between the polarizer 21 and the second protective layer 23.

(1) Polarizer The polarizing element 21 is preferably made of a polyvinyl alcohol-based resin film in which a dichroic dye is adsorbed and oriented.

The polyvinyl alcohol-based resin constituting the polarizer 21 is obtained by saponifying the polyvinyl acetate-based resin. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith. Examples of other monomers copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids and the like.

The degree of saponification of the polyvinyl alcohol-based resin is usually in the range of 85 to 100 mol%, preferably 98 to 100 mol%. The polyvinyl alcohol-based resin may be further modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol-based resin is usually in the range of 1,000 to 10,000, preferably 1,500 to 5,000.

The polarizer 21 as described above includes a step of uniaxially stretching a polyvinyl alcohol-based resin film, a step of dyeing a polyvinyl alcohol-based resin film with a dichroic dye, and adsorbing the dichroic dye. It is preferably produced by undergoing a step of treating the adsorbed polyvinyl alcohol-based resin film with an aqueous boric acid solution.

The uniaxial stretching may be performed before the dyeing with the dichroic dye, at the same time as the dyeing with the dichroic dye, or after the dyeing with the dichroic dye. When the uniaxial stretching is performed after dyeing with a dichroic dye, the uniaxial stretching may be performed before the boric acid treatment or during the boric acid treatment. Of course, it is also possible to perform uniaxial stretching at these a plurality of stages. For uniaxial stretching, rolls having different peripheral speeds may be uniaxially stretched, or thermal rolls may be used to uniaxially stretch the rolls. Further, it may be a dry stretching performed in the air, or a wet stretching performed in a state of being swollen with a solvent. The draw ratio is usually about 4 to 8 times.

To dye the polyvinyl alcohol-based resin film with a dichroic dye, for example, the polyvinyl alcohol-based resin film may be immersed in an aqueous solution containing the dichroic dye. Specifically, iodine or a dichroic organic dye is used as the dichroic dye.

When iodine is used as the dichroic dye, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide for dyeing is usually adopted. The iodine content in this aqueous solution is usually about 0.01 to 0.5 parts by mass per 100 parts by mass of water, and the content of potassium iodide is usually about 0.5 to 10 parts by mass per 100 parts by mass of water. Is. The temperature of this aqueous solution is usually about 20 to 40 ° C., and the immersion time (staining time) in this aqueous solution is usually about 30 to 300 seconds.

The boric acid treatment after dyeing with a dichroic dye is performed by immersing the dyed polyvinyl alcohol-based resin film in an aqueous boric acid solution. The content of boric acid in the boric acid aqueous solution is usually about 2 to 15 parts by mass, preferably about 5 to 12 parts by mass per 100 parts by mass of water. When iodine is used as the dichroic pigment, this boric acid aqueous solution preferably contains potassium iodide. The content of potassium iodide in the boric acid aqueous solution is usually about 2 to 20 parts by mass, preferably 5 to 15 parts by mass per 100 parts by mass of water. The immersion time in the boric acid aqueous solution is usually about 100 to 1,200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. The temperature of the boric acid aqueous solution is usually 50 ° C. or higher, preferably 50 to 85 ° C.

The polyvinyl alcohol-based resin film after the boric acid treatment is usually washed with water. The water washing treatment is performed, for example, by immersing a boric acid-treated polyvinyl alcohol-based resin film in water. After washing with water, a drying treatment is performed to obtain a polarizer 21. The temperature of water in the washing treatment is usually about 5 to 40 ° C., and the immersion time is usually about 2 to 120 seconds. Subsequent drying treatments are usually performed using a hot air dryer or a far infrared heater. The drying temperature is usually 40 to 100 ° C. The drying treatment time is usually about 120 to 600 seconds.

The thickness of the polarizer 21 is preferably about 3 to 50 μm, and particularly preferably about 3 to 15 μm when thinning is required.

(2) Protective Layer The first protective layer 22 and the second protective layer 23 (hereinafter, may be collectively referred to as “protective layers 22, 23”) are preferably made of a transparent resin film. The transparent resin film constituting the protective layers 22 and 23 may be either a non-stretched film or a uniaxially or biaxially stretched film.

The main component of the transparent resin film constituting the first protective layer 22 is preferably at least selected from the group consisting of polyester-based resin, polycarbonate-based resin, acrylic-based resin, amorphous polyolefin-based resin, and cellulose-based resin. It is a kind of resin. Among the above, the first protective layer 22 is preferably made of a cellulosic resin.

The cellulosic resin is a resin in which at least a part of the hydroxyl groups in cellulose is acetic acid esterified, and even if it is a mixed ester in which a part is acetic acid esterified and a part is esterified with another acid. Good. The cellulosic resin is preferably a cellulosic ester resin, and more preferably an acetyl cellulosic resin. Specific examples of the acetyl cellulose-based resin include triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate. Examples of commercially available films made of such acetyl cellulose-based resins include "Fujitac TD80", "Fujitac TD80UF" and "Fujitac TD80UZ" manufactured by Fujifilm Co., Ltd., and "KC8UX2M" manufactured by Konica Minolta Opto Co., Ltd. , "KC2UA", "KC8UY" and the like.

A cellulosic resin film to which an optical compensation function is provided can also be used. Examples of such an optical compensation film include a film in which a cellulosic resin contains a compound having a phase difference adjusting function, a film in which a compound having a phase difference adjusting function is coated on the surface of the cellulosic resin, and a cellulosic resin uniaxially or biaxially. Examples thereof include a film obtained by stretching on a shaft. Examples of commercially available cellulosic resin optical compensation films include "Wide View Film WV BZ 438" and "Wide View Film WV EA" manufactured by FUJIFILM Corporation, and "Wide View Film WV EA" manufactured by Konica Minolta Opto Co., Ltd. There are "KC4FR-1" and "KC4HR-1" and the like.

Among the above-mentioned cellulosic resins, the first protective layer 22 is more preferably made of a cellulose ester resin, particularly preferably made of an acetyl cellulose resin, and further preferably made of triacetyl cellulose.

On the other hand, the main component of the transparent resin film constituting the second protective layer 23 is preferably an acrylic resin, and in particular, the second protective layer 23 can be easily thinned without impairing the polarization performance. Therefore, it is preferably made of an acrylic resin. In this case, in the layer in which the pressure-sensitive adhesive layer in contact with the second protective layer 23 is made of a conventional acrylic pressure-sensitive adhesive composition, the antistatic agent (C) in the pressure-sensitive adhesive is sucked out, and the second protective layer 23 and the second protective layer 23 This will reduce the adhesion of the interface with the pressure-sensitive adhesive layer. However, in the case of the pressure-sensitive adhesive layer 1 formed from the pressure-sensitive adhesive composition P in the present embodiment, the oxyalkylene group traps the antistatic agent (C) to the extent that the adhesive strength is not insufficient, whereby the above-mentioned The suction phenomenon can be effectively prevented. As a result, the pressure-sensitive adhesive layer 1 has high adhesion to the second protective layer 23. Therefore, the optical film 10A with an adhesive layer has excellent durability even under high temperature conditions, moist heat conditions, heat shock, and the like.

The acrylic resin forming the second protective layer 23 is preferably a polymer containing a methacrylic acid ester as a main monomer, and is a copolymer in which a small amount of other comonomer components are copolymerized. Is particularly preferred. This copolymer can usually be obtained by polymerizing a monofunctional monomer containing methyl methacrylate and methyl acrylate in the presence of a radical polymerization initiator and a chain transfer agent. In addition, the acrylic resin can be copolymerized with a third monofunctional monomer.

Third monofunctional monomers capable of copolymerizing with methyl methacrylate and methyl acrylate include, for example, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate. , And methacrylic acid esters other than methyl methacrylate, such as 2-hydroxyethyl methacrylate; ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, and 2 acrylate. Acrylic esters such as −hydroxyethyl; methyl 2- (hydroxymethyl) acrylate, methyl 2- (1-hydroxyethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, and 2- (hydroxymethyl) acrylic. Hydroxyalkyl acrylate esters such as butyl acrylate; unsaturated acids such as methacrylic acid and acrylate; halogenated styrenes such as chlorostyrene and bromostyrene; substituted styrenes such as vinyltoluene and α-methylstyrene; acrylonitrile and methacrylic acid. Unsaturated nitriles such as ronitrile; unsaturated acid anhydrides such as maleic anhydride and citraconic anhydride; unsaturated imides such as phenylmaleimide and cyclohexylmaleimide can be mentioned. Each of these may be used alone, or a plurality of different types may be used in combination.

When the polyfunctional monomer is copolymerized, examples of the polyfunctional monomer that can be copolymerized with methyl methacrylate and methyl acrylate include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, and triethylene. Acrylate or the hydroxyl groups at both ends of ethylene glycol such as glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, nonaethylene glycol di (meth) acrylate, and tetradecaethylene glycol di (meth) acrylate Esterated with methacrylic acid; esterified at both terminal hydroxyl groups of propylene glycol or its oligomer with acrylic acid or methacrylic acid; neopentyl glycol di (meth) acrylate, hexanediol di (meth) acrylate, and butanediol di The hydroxyl group of a dihydric alcohol such as (meth) acrylate esterified with acrylic acid or methacrylic acid; bisphenol A, an alkylene oxide adduct of bisphenol A, or both terminal hydroxyl groups of these halogen substituents are acrylic acid or methacrylic acid. Esterated with acrylate: Polyhydric alcohols such as trimethylolpropane and pentaerythritol esterified with acrylic acid or methacrylic acid, and glycidyl acrylate or glycidyl methacrylate epoxy group added by ring opening to these terminal hydroxyl groups; Dibasic acids such as succinic acid, adipic acid, terephthalic acid, phthalic acid, halogen substituents thereof, and alkylene oxide adducts thereof to which an epoxy group of glycidyl acrylate or glycidyl methacrylate is ring-opened; aryl ( Meta) Acrylate; Examples thereof include aromatic divinyl compounds such as divinylbenzene. Of these, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and neopentyl glycol dimethacrylate are preferably used.

The acrylic resin having such a composition may be further modified by reacting between the functional groups of the copolymer. Examples of the reaction include a demethanol condensation reaction in a polymer chain between a methyl ester group of methyl acrylic acid and a hydroxyl group of methyl 2- (hydroxymethyl) acrylic acid, and a carboxyl group of acrylic acid and 2- (hydroxymethyl) acrylic. Examples thereof include a dehydration condensation reaction in a polymer chain with a hydroxyl group of methyl acid.

The glass transition temperature (Tg) of the acrylic resin is preferably in the range of 80 to 120 ° C. In order to adjust the glass transition temperature (Tg) of an acrylic resin to the above range, the polymerization ratio of the methacrylic acid ester-based monomer and the acrylic acid ester-based monomer, the carbon chain length of each ester group, and the carbon chain length thereof are usually adjusted. A method of appropriately selecting the type of functional group to have and the polymerization ratio of the polyfunctional acrylic monomer with respect to the entire monomer is adopted.

The acrylic resin may contain a known additive, if necessary. Known additives include, for example, lubricants, antiblocking agents, heat stabilizers, antioxidants, antistatic agents, lightfasteners, impact resistance improvers, surfactants and the like. However, since transparency is required as a protective film laminated on the polarizer, it is preferable to keep the amount of these additives to a minimum.

As a method for producing the acrylic resin film, any method such as a melt casting method, a melt extrusion method such as a T-die method or an inflation method, or a calendar method may be used. Among them, a method of melt-extruding a raw material resin from, for example, a T-die and bringing at least one side of the obtained film-like material into contact with a roll or a belt to form a film is preferable in that a film having good surface properties can be obtained.

The acrylic resin may contain acrylic rubber particles which are impact improving agents from the viewpoint of film forming property on the film and impact resistance of the film. The acrylic rubber particles referred to here are particles containing an elastic polymer mainly composed of an acrylic acid ester as an essential component, and those obtained by uniformly forming the elastic polymer into particles or by using this elastic polymer as 1 An example has a multi-layer structure having two layers.

Examples of such an elastic polymer include a crosslinked elastic copolymer containing an alkyl acrylate as a main component and copolymerizing another copolymerizable vinyl monomer and a crosslinkable monomer. Examples of the alkyl acrylate that is the main component of the elastic polymer include those having an alkyl group having about 1 to 8 carbon atoms, such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, and in particular, carbon. An acrylate having an alkyl group of several 4 or more is preferably used. Examples of other vinyl monomers copolymerizable with this alkyl acrylate include compounds having one polymerizable carbon-carbon double bond in the molecule, and more specifically, a methacrylic acid ester such as methyl methacrylate. , Aromatic vinyl compounds such as styrene, vinyl cyan compounds such as acrylonitrile, and the like. Examples of the crosslinkable monomer include a crosslinkable compound having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, ethylene glycol di (meth) acrylate and butanediol. Examples thereof include (meth) acrylates of polyhydric alcohols such as di (meth) acrylate, alkenyl esters of (meth) acrylic acid such as allyl (meth) acrylate, and divinylbenzene.

Further, the laminate of the film made of an acrylic resin containing no rubber particles and the film made of an acrylic resin containing rubber particles can be used as the protective layers 22 and 23. Acrylic resins can be easily obtained on the market. For example, under the trade names, Sumipex (manufactured by Sumitomo Chemical Co., Ltd.), Acrypet (manufactured by Mitsubishi Rayon Co., Ltd.), and Delpet (Asahi Kasei Co., Ltd.) (Manufactured by Co., Ltd.), Parapet (manufactured by Clare Co., Ltd.), Acrylic (manufactured by Nippon Shokubai Co., Ltd.), etc.

The protective layers 22 and 23 may contain an ultraviolet absorber. This is because the liquid crystal cell can be protected from deterioration due to ultraviolet rays by arranging the protective layer containing the ultraviolet absorber on the visible side of the liquid crystal cell.

Here, the first protective layer 22 and the second protective layer 23 may be made of the same kind of transparent resin film or may be made of different kinds of transparent resin films.

The protective layers 22 and 23 may be subjected to an easy-adhesion treatment such as a saponification treatment, a corona treatment, a primer treatment, an anchor coating treatment or the like on the bonded surface prior to the bonding to the polarizing element 21. Further, various treatment layers such as a hard coat layer, an antireflection layer, and an antiglare layer may be provided on the surface of the protective layers 22 and 23 opposite to the surface to be bonded to the polarizer 21.

The thickness of the protective layers 22 and 23 is usually 5 μm or more, preferably 10 μm or more. The thickness of the protective layers 22 and 23 is usually 200 μm or less, preferably 120 μm or less, particularly preferably 85 μm or less, and further preferably 30 μm or less.

(3) Adhesive Layer An adhesive constituting an adhesive layer that may be interposed between the polarizer 21 and the first protective layer 22 and / or between the polarizer 21 and the second protective layer 23. As appropriate, an appropriate one can be used depending on the type and purpose of the adherend. For example, solvent-based adhesives, emulsion-type adhesives, water-based adhesives, pressure-sensitive adhesives, re-wet-sensitive adhesives, polycondensation-type adhesives, solvent-free adhesives, film-like adhesives, hot-melt adhesives, etc. Can be mentioned.

One preferable adhesive constituting the above-mentioned adhesive is a water-based adhesive, and a typical example thereof is one containing a polyvinyl alcohol-based resin as a main component. Examples of commercially available polyvinyl alcohol-based resins that can be water-based adhesives include "KL-318" manufactured by Kuraray Co., Ltd.

The water-based adhesive may contain a cross-linking agent. As the cross-linking agent, amine compounds, aldehyde compounds, methylol compounds, epoxy compounds, isocyanate compounds, polyvalent metal salts and the like are preferable, and epoxy compounds are particularly preferable. Commercially available cross-linking agents include, for example, glyoxal and "Smilase Resin 650 (30)", which is an aqueous solution of a water-soluble epoxy compound sold by Sumika Chemtex Co., Ltd.

Other preferable adhesives include adhesives composed of an epoxy resin composition containing an epoxy resin that is cured by irradiation with active energy rays or heating. When the adhesive is used, the adhesion between the films irradiates or heats the adhesive layer interposed between the films with active energy rays to cure the curable epoxy resin contained in the adhesive. It can be done by. Curing of the epoxy resin by irradiation or heating with active energy rays is preferably performed by cationic polymerization of the epoxy resin. In the present specification, the epoxy resin means a compound having two or more epoxy groups in the molecule.

From the viewpoint of weather resistance, refractive index, cationic polymerizable property, etc., the epoxy resin contained in the curable epoxy resin composition as an adhesive is preferably an epoxy resin containing no aromatic ring in the molecule. Examples of such epoxy resins include hydrogenated epoxy resins, alicyclic epoxy resins, and aliphatic epoxy resins.

(4) Method for manufacturing the polarizing plate The polarizing plate 2A can be manufactured by a usual method. Hereinafter, as an example, a manufacturing method when a water-based adhesive is used as the adhesive will be described.

First, an adhesive layer is formed on the bonding surface of the polarizer 21 or the bonding surface of the protective layers 22 and 23. For forming the adhesive layer, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method and the like can be used. Further, it is also possible to adopt a method in which the polarizer 21 and the protective layers 22 and 23 are continuously supplied so that the bonding surface of both is on the inside, and the adhesive is spread between them. After applying the adhesive, heat treatment is applied as necessary to evaporate the water content and dry the adhesive layer.

The thickness of the adhesive layer can be arbitrarily set by designing the characteristics of the polarizing plate 2A, but from the viewpoint of reducing the cost of the adhesive material, a smaller thickness is preferable, and from the viewpoint of suppressing defects such as air bubbles and foreign substances during bonding. Therefore, it is preferable that the size is large, and from the viewpoint of adhesion and durability, it is preferable to carry out the operation within the optimum range determined for each combination of the adherend and the adhesive. The film thickness of the adhesive layer is generally 0.005 μm or more, preferably 0.01 μm or more, and more preferably 0.03 μm or more. The film thickness is generally 10 μm or less, preferably 5 μm or less, and more preferably 1 μm or less.

When adhering the polarizer 21 and the protective layers 22 and 23, corona discharge treatment, plasma treatment, flame treatment, and primer treatment are performed on one or both of the bonding surfaces of both before forming an adhesive coating layer. , An easy-adhesion treatment such as an anchor coating treatment may be applied.

After the adhesive layer is formed as described above, the first protective layer 22 is attached to one surface of the polarizer 21 and the second protective layer 23 is attached to the polarizer 21 via the adhesive layer. Adhere to the other side of. As a result, a polarizing plate 2A formed by laminating the first protective layer 22, the polarizer 21, and the second protective layer 23 can be obtained.

The total thickness of the polarizing plate 2A is usually about 15 to 400 μm, and is preferably 20 μm or more, particularly 30 μm or more, from the viewpoint of maintaining polarization performance while meeting the demand for thinning in mobile applications. preferable. From the same viewpoint, the total thickness is preferably 100 μm or less, and particularly preferably 80 μm or less.

(5) Method for Manufacturing Optical Film with Adhesive Layer As a preferable example of the method for manufacturing the optical film 10A with a pressure-sensitive adhesive layer, first, a release sheet is formed on one or both sides of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition P. To manufacture an adhesive sheet made by laminating. Here, as an example, it is assumed that a pressure-sensitive adhesive sheet formed by laminating release sheets on both sides of the pressure-sensitive adhesive layer is manufactured.

Examples of the release sheet include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polyethylene naphthalate film, and polybutylene terephthalate film. Polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, etc. Is used. In addition, these crosslinked films are also used. Further, these laminated films may be used.

It is preferable that at least one surface of the release sheet (particularly the release surface in contact with the pressure-sensitive adhesive layer) is subjected to a release treatment. Examples of the release agent used in the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents. The peeling surface of the release sheet in the present specification means a surface of the release sheet that has peelability, and includes both a surface that has been peeled and a surface that exhibits peelability without peeling. ..

When laminating the release sheets on both sides of the pressure-sensitive adhesive layer, it is preferable that one release sheet is a heavy release type release sheet having a large release force and the other release sheet is a light release type release sheet having a small release force.

The thickness of the release sheet is not particularly limited, but is usually about 20 to 150 μm.

As an example of the method for producing the pressure-sensitive adhesive sheet, a coating solution of the pressure-sensitive adhesive composition P is applied to the peel-off surface of the release sheet, and heat treatment is performed to form a coating film. Laminate the release sheet (so that the release surface is in contact with the coating film) or the base material. The coating film becomes an adhesive layer as it is when the curing period is unnecessary, and becomes an adhesive layer after the curing period elapses when the curing period is required. The conditions for heat treatment and curing are as described above.

As a method for applying the coating solution, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method and the like can be used.

One of the release sheets (light release type release sheet) is peeled from the adhesive sheet obtained as described above. Then, the second protective layer 23 of the polarizing plate 2A is superposed on the exposed pressure-sensitive adhesive layer, and the pressure-sensitive adhesive sheet and the polarizing plate 2A are pressure-bonded. As a result, the optical film 10A with an adhesive layer (with a release sheet) can be obtained.

As another example of the method for producing the optical film 10A with an adhesive layer, a solution (coating solution) containing the above-mentioned adhesive composition P is applied to the peeled surface of the release sheet, and heat treatment is performed to form a coating film. After the formation, the second protective layer 23 of the polarizing plate 2A is superposed on the coating film. When the curing period is required, the curing period is set, and when the curing period is not required, the coating film becomes the adhesive layer 1 as it is. As a result, the optical film 10A with an adhesive layer (with a release sheet) can be obtained.

2. 2. Example of Optical Film as Composite Polarizing Plate An example of the optical film with an adhesive layer according to the present embodiment when the optical film is a composite polarizing plate having a retardation plate will be described with reference to FIG. As shown in FIG. 2, the optical film 10B with an adhesive layer according to the present embodiment is a pressure-sensitive adhesive laminated on one surface (lower surface in FIG. 2) of the composite polarizing plate 2B and the composite polarizing plate 2B. It is configured with layer 1. Although not shown, a release sheet may be laminated on the surface of the pressure-sensitive adhesive layer 1 opposite to the side of the composite polarizing plate 2B until the optical film 10B with the pressure-sensitive adhesive layer is used.

The pressure-sensitive adhesive layer 1 is made of a pressure-sensitive adhesive obtained from the above-mentioned pressure-sensitive adhesive composition P.

The composite polarizing plate 2B in the present embodiment has a first retardation plate 24 in contact with the pressure-sensitive adhesive layer 1 and a second position on the first retardation plate 24 opposite to the pressure-sensitive adhesive layer 1 side. The second pressure-sensitive adhesive layer 26 interposed between the retardation plate 25, the first retardation plate 24 and the second retardation plate 25, and the second pressure-sensitive adhesive layer 26 side of the second retardation plate 25. A polarizing element 21 laminated on the opposite side to the above, and a protective layer 27 laminated on the side opposite to the second retardation plate 25 side of the polarizing element 21 are provided. Although not shown, an adhesive layer may be interposed between the polarizer 21 and the protective layer 27 and / or between the polarizer 21 and the second retardation plate 25. Such a composite polarizing plate 2B satisfactorily exhibits the performance of viewing angle compensation.

(1) First Phase Difference Plate The first phase difference plate 24 may be composed of a single layer that expresses a phase difference, or may be composed of a plurality of layers including a phase difference expression layer. The first retardation plate 24 is preferably laminated on one surface (lower surface in FIG. 3) of the retardation expression layer 242 and the retardation expression layer 242, as shown in FIG. The acrylic resin layer 241 of No. 1 and the second acrylic resin layer 243 laminated on the other surface (upper surface in FIG. 3) of the retardation expression layer 242 are provided. The retardation layer 242 is preferably made of a styrene resin from the viewpoint that the intrinsic birefringence is negative and the thin film can be easily formed. As described above, it has a first retardation plate 24 including a first acrylic resin layer 241, a retardation expression layer 242 made of a styrene resin, and a second acrylic resin layer 243. The composite polarizing plate 2B is excellent in the performance of viewing angle compensation of a liquid crystal display device, particularly an IPS (In-Place-Switching) mode liquid crystal display device. Further, since the retardation expression layer 242 is protected by the first acrylic resin layer 241 and the second acrylic resin layer 243 existing on both sides thereof, the first retardation plate 24 is the retardation expression layer. The optical performance of 242 is not impaired, and the mechanical strength and chemical resistance are excellent.

When the layer in contact with the pressure-sensitive adhesive layer 1 in the first retardation plate 24 is the first acrylic resin layer 241, the pressure-sensitive adhesive layer in contact with the first acrylic resin layer 241 is a conventional acrylic pressure-sensitive adhesive. In the layer made of the composition, the antistatic agent (C) in the pressure-sensitive adhesive is sucked out, and the adhesion of the interface between the first acrylic resin layer 241 and the pressure-sensitive adhesive layer is lowered. However, in the case of the pressure-sensitive adhesive layer 1 formed from the pressure-sensitive adhesive composition P in the present embodiment, the oxyalkylene group traps the antistatic agent (C) to the extent that the adhesive strength is not insufficient, whereby the above-mentioned The suction phenomenon can be effectively prevented. As a result, the pressure-sensitive adhesive layer 1 has high adhesion to the first retardation plate 24. Therefore, the optical film 10B with an adhesive layer has excellent durability even under high temperature conditions, moist heat conditions, heat shock, and the like.

It is preferable that the first retardation plate 24 is provided with in-plane retardation by stretching. As a result, the performance of the viewing angle compensation becomes better.

The styrene-based resin constituting the retardation layer 242 may be a homopolymer of styrene or a derivative thereof, or a binary or higher copolymerization of styrene or a derivative thereof and another copolymerizable monomer. It may be coalesced. The styrene derivative is a compound in which another group is bonded to styrene, and is, for example, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, o-ethylstyrene, p-ethyl. Introducing hydroxyl group, alkoxy group, carboxyl group, halogen, etc. into the benzene nucleus of styrene such as alkyl styrene such as styrene, hydroxy styrene, tert-butoxystyrene, vinyl benzoic acid, o-chlorostyrene, p-chlorostyrene, etc. Examples thereof include substituted styrene.

As the styrene resin, a ternary copolymer as disclosed in JP-A-2003-50316 and JP-A-2003-207640 can also be used.

The styrene resin constituting the retardation layer 242 is preferably a copolymer of styrene or a styrene derivative and at least one monomer selected from acrylonitrile, maleic anhydride, methyl methacrylate and butadiene.

Further, as the styrene resin constituting the retardation expression layer 242, a styrene resin having heat resistance is preferable. The glass transition temperature (Tg) of the styrene resin is generally 100 ° C. or higher, but a styrene resin having a glass transition temperature (Tg) of 120 ° C. or higher is preferable.

The thickness of the phase difference expression layer 242 is preferably 10 to 100 μm. When the thickness of the retardation expression layer 242 is 10 μm or more, a sufficient retardation value is expressed by stretching. On the other hand, when the thickness of the retardation expression layer 242 is 100 μm or less, the impact strength is high, the retardation change due to external stress is small, and thermal unevenness or the like is unlikely to occur when applied to a liquid crystal display device.

The first acrylic resin layer 241 and the second acrylic resin layer 243 are preferably made of a (meth) acrylic resin composition in which rubber particles are mixed with the (meth) acrylic resin. By blending the rubber particles, the impact resistance of the acrylic resin layer can be enhanced.

Examples of the (meth) acrylic resin include homopolymers of methacrylic acid alkyl esters or acrylic acid alkyl esters, copolymers of methacrylic acid alkyl esters and acrylic acid alkyl esters, and the like. Examples of the alkyl methacrylate ester include methyl methacrylate, ethyl methacrylate, propyl methacrylate and the like. Examples of the acrylic acid alkyl ester include methyl acrylate, ethyl acrylate, propyl acrylate and the like. As such a (meth) acrylic resin, a commercially available general-purpose (meth) acrylic resin can be used. Among the (meth) acrylic resins, there are those called impact-resistant (meth) acrylic resins and highly heat-resistant (meth) acrylic resins having a glutaric anhydride structure or a lactone ring structure in the main chain. Also includes what is called.

The rubber particles blended in the (meth) acrylic resin are preferably acrylic particles. Acrylic-based rubber particles are particles having rubber elasticity obtained by polymerizing an acrylic acid alkyl ester such as butyl acrylate or 2-ethylhexyl acrylate as a main component in the presence of a polyfunctional monomer.

The rubber particles may be a material obtained by uniformly forming a material having rubber elasticity into particles, or may be a multilayer structure having at least one rubber elastic layer. As the acrylic rubber particles having a multi-layer structure, those having the above-mentioned particles having rubber elasticity as nuclei and covering them with a hard methacrylic acid alkyl ester polymer, and hard methacrylic acid alkyl ester polymers are used. The core is made of an acrylic polymer having rubber elasticity as described above, and the hard core is covered with an acrylic polymer having rubber elasticity, and the periphery thereof is hard methacrylic acid. Examples thereof include those covered with an alkyl ester-based polymer.

The average diameter of the rubber particles is preferably about 50 to 400 nm. The average diameter of the rubber particles can be measured by the laser diffraction / scattering method.

The content of the rubber particles in the (meth) acrylic resin composition constituting the first acrylic resin layer 241 and the second acrylic resin layer 243 is 5 to 100 parts by mass of the (meth) acrylic resin. It is preferably about 50 parts by mass.

The (meth) acrylic resin composition constituting the first acrylic resin layer 241 and the second acrylic resin layer 243 is commercially available in a state in which the (meth) acrylic resin and the acrylic rubber particles are mixed. Can be used. Examples of commercially available products of (meth) acrylic resin ((meth) acrylic resin composition) containing acrylic rubber particles are "HT55X" sold by Sumitomo Chemical Co., Ltd. under their respective trade names. And "Technoloy S001" and the like.

The glass transition temperature (Tg) of the (meth) acrylic resin composition is generally 160 ° C. or lower, but a (meth) acrylic resin composition having a glass transition temperature (Tg) of 120 ° C. or lower is preferable, and 110 ° C. or lower is particularly preferable. A (meth) acrylic resin composition at ° C. or lower is preferable. That is, it is preferable that the glass transition temperature (Tg) of the phase difference developing layer 242 and the glass transition temperature (Tg) of the first acrylic resin layer 241 and the second acrylic resin layer 243 do not overlap, and the phase difference is expressed. The layer 242 preferably has a higher glass transition temperature (Tg) than the first acrylic resin layer 241 and the second acrylic resin layer 243.

The materials of the first acrylic resin layer 241 and the second acrylic resin layer 243 may be the same or different.

The thickness of the first acrylic resin layer 241 and the second acrylic resin layer 243 is preferably 10 to 100 μm, respectively. If the thickness is 10 μm or more, the film can be easily formed, and if the thickness is 100 μm or less, the retardation of the first acrylic resin layer 241 and the second acrylic resin layer 243 is ignored. Can be done. It is preferable that the thickness of the first acrylic resin layer 241 and the thickness of the second acrylic resin layer 243 are substantially the same.

The surface of the first retardation plate 24 on the side of the second pressure-sensitive adhesive layer 26 may be subjected to surface treatment such as corona treatment.

In order to produce the first retardation plate 24, for example, a styrene resin and a (meth) acrylic resin composition containing rubber particles may be coextruded and then stretched. Stretching can be performed by longitudinal uniaxial stretching, tenter horizontal uniaxial stretching, simultaneous biaxial stretching, sequential biaxial stretching, or the like, and may be stretched so as to obtain a desired retardation value. In addition to the above methods, after preparing single-layer films (phase difference expression layer 242, first acrylic resin layer 241 and second acrylic resin layer 243), they are heat-fused by heat lamination. And the laminated body may be stretched.

The total thickness of the first retardation plate 24 after stretching is preferably 5 μm or more, preferably 10 μm or more, from the viewpoint of meeting the demand for thinning in mobile applications while maintaining sufficient performance. It is more preferable, and it is particularly preferable that it is 15 μm or more. From the same viewpoint, the total thickness is preferably 100 μm or less, more preferably 50 μm or less, and particularly preferably 30 μm or less.

In the first retardation plate 24, the surface in contact with the pressure-sensitive adhesive layer 1 is composed of the first acrylic resin layer 241. In this case as well, the pressure-sensitive adhesive layer 1 is relative to the first acrylic resin layer 241. The adhesive strength is high, and therefore, the optical film 10B with an adhesive layer has excellent durability even under high temperature conditions, moist heat conditions, heat shock, and the like.

(2) Second Phase Difference Plate The second retardation plate 25 is preferably made of an olefin resin. The olefin resin is a structural unit derived from a chain aliphatic olefin such as ethylene and propylene, or an alicyclic olefin such as norbornene or a substitute thereof (hereinafter, these are collectively referred to as a norbornene monomer). It is a resin. The olefin resin may be a copolymer using two or more kinds of monomers.

Among them, as the olefin resin, a cyclic olefin resin which is a resin mainly containing a structural unit derived from an alicyclic olefin is preferably used. Typical examples of the alicyclic olefin constituting the cyclic olefin resin include norbornene-based monomers. Norbornene is a compound in which one carbon-carbon bond of norbornane is a double bond, and is named bicyclo [2,2,1] hept-2-ene according to the IUPAC nomenclature. is there. Examples of the substitution product of norbornene include 3-substitution, 4--substituted, 4,5-di-substituted, etc., with the double bond position of norbornene at the 1- and 2-positions, and further, di-substituted. Cyclopentadiene, dimethanooctahydronaphthalene and the like can also be used as monomers constituting the cyclic olefin resin.

The cyclic olefin resin may or may not have a norbornane ring as its constituent unit. Examples of the norbornene-based monomer forming a cyclic olefin-based resin having no norbornene ring as a constituent unit include those having a 5-membered ring by ring-opening, typically norbornene, dicyclopentadiene, 1- or 4-. Examples thereof include methylnorbornene and 4-phenylnorbornene. When the cyclic olefin-based resin is a copolymer, the arrangement state of the molecule is not particularly limited, and it may be a random copolymer, a block copolymer, or a graft. It may be a polymer.

More specific examples of the cyclic olefin resin include, for example, a ring-opening polymer of a norbornene-based monomer, a ring-opening copolymer of a norbornene-based monomer and another monomer, and addition of maleic acid and cyclopentadiene to them. Examples thereof include the polymer modified products made, polymers or copolymers obtained by hydrogenating them, addition polymers of norbornene-based monomers, and addition copolymers of norbornene-based monomers and other monomers. Examples of other monomers used as copolymers include α-olefins, cycloalkenes, non-conjugated dienes and the like. Further, the cyclic olefin resin may be a copolymer using one or more of norbornene-based monomers and other alicyclic olefins.

Among the above specific examples, as the cyclic olefin-based resin, a resin obtained by hydrogenating a ring-opening polymer using a norbornene-based monomer is preferably used. Such a cyclic olefin resin can be stretched to form a retardation plate, and in addition to stretching, a shrinkable film having a predetermined shrinkage rate is laminated and heat-shrinked. A retardation plate having high uniformity and a large retardation value can also be used.

Commercially available cyclic olefin resins using norbornene-based monomers are all under the trade names "Zeonex" and "Zeonoa" sold by Zeon Corporation, and "Zeonoa" sold by JSR Corporation. There are "Arton" and so on. Commercially available products of these cyclic olefin resin films and stretched films thereof are also available. For example, all of them are trade names such as "Zeonoa Film" sold by Nippon Zeon Co., Ltd. and JSR Co., Ltd. There are "Arton Film" sold and "Scina" sold by Sekisui Chemical Co., Ltd.

Further, as the second retardation plate 25, a film made of a mixed resin containing two or more kinds of olefin resins or a film made of a mixed resin of an olefin resin and another thermoplastic resin can be used. For example, as a mixed resin containing two or more kinds of olefin resins, a mixture of a cyclic olefin resin and a chain aliphatic olefin resin as described above can be mentioned. When a mixed resin of an olefin resin and another thermoplastic resin is used, an appropriate other thermoplastic resin is appropriately selected according to the purpose. Specific examples include polyvinyl chloride resin, cellulose resin, polystyrene resin, acrylonitrile / butadiene / styrene copolymer resin, acrylonitrile / styrene copolymer resin, (meth) acrylic resin, polyvinyl acetate resin, and polychloride. Vinylidene resin, polyamide resin, polyacetal resin, polycarbonate resin, modified polyphenylene ether resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polyphenylene sulfide resin, polysulfone resin, polyether sulfone resin, polyether Examples thereof include ether ketone resins, polyarylate resins, liquid crystal resins, polyamideimide resins, polyimide resins, and polytetrafluoroethylene resins. Only one type of thermoplastic resin can be used alone or in combination of two or more types. Further, the above-mentioned thermoplastic resin can be used after undergoing any appropriate polymer modification. Examples of polymer modification include copolymerization, cross-linking, molecular end modification, and imparting stereoregularity.

When a mixed resin of an olefin resin and another thermoplastic resin is used, the content of the other thermoplastic resin is usually about 50% by mass or less, preferably about 40% by mass or less, based on the whole resin. By keeping the content of other thermoplastic resins within this range, the absolute value of the photoelastic coefficient is small, the wavelength dispersion characteristics are good, and the retardation plate is excellent in durability, mechanical strength and transparency. Can be obtained.

The olefin resin can be formed into a film by a casting method from a solution, a melt extrusion method, or the like. When forming a film from two or more kinds of mixed resins, the film forming method is not particularly limited. For example, a film is formed by a casting method using a uniform solution obtained by stirring and mixing resin components with a solvent at a predetermined ratio. A method for producing the film, a method for producing a film by a melt extrusion method in which resin components are melt-mixed at a predetermined ratio, and the like are adopted.

The film made of the olefin resin may contain other components such as a residual solvent, a stabilizer, a plasticizer, an antiaging agent, an antistatic agent, and an ultraviolet absorber, if necessary. Further, a leveling agent may be contained in order to reduce the surface roughness.

The surface of the second retardation plate 25 on the side of the second pressure-sensitive adhesive layer 26 may be subjected to surface treatment such as corona treatment.

The second retardation plate 25 has the following when the refractive indexes in the in-plane slow phase axial direction, the in-plane advance phase axial direction, and the thickness direction are n _x , n _y, and n _z , respectively, and the thickness of the film is d. Equation (1):
_Re = (n _{x −} n _y ) × d (1)
In-plane retardation value _{R e} in the definition is the wavelength 590nm is 30 to 150 nm, the following formula (2):
Nz coefficient = (n _{x −} n _z ) / (n _{x −} n _y ) (2)
It is preferable that the Nz coefficient defined in is having a refractive index anisotropy of more than 1 and less than 2.

The second retardation plate 25 having the above-mentioned refractive index anisotropy can be obtained by vertical uniaxial stretching, tenter horizontal uniaxial stretching, simultaneous biaxial stretching, sequential biaxial stretching, or the like of a film made of the olefin resin. In addition to appropriately adjusting the stretching ratio and stretching speed, various temperatures such as preheating temperature, stretching temperature, heat setting temperature, and cooling temperature at the time of stretching, and their patterns are appropriately selected to change the desired refractive index. You can get anisotropy.

The thickness of the second retardation plate 25 is preferably 5 μm or more, and particularly preferably 10 μm or more. The thickness is preferably 80 μm or less, and particularly preferably 30 μm or less.

(3) Second Adhesive Layer As the adhesive constituting the second adhesive layer 26, a known adhesive can be used, and it may be a curable adhesive or a non-curable adhesive. Although it may be a pressure-sensitive adhesive, it is preferable to use an active energy ray-curable pressure-sensitive adhesive from the viewpoint of suppressing dimensional changes due to heat shrinkage of the polarizing plate.

The active energy ray-curable pressure-sensitive adhesive may be mainly composed of a polymer having active energy ray-curability, a polymer having no active energy ray-curable property, an active energy ray-curable polyfunctional monomer, and an active energy ray-curable polymer. / Or a mixture with an oligomer may be used as a main component. Further, it may be a mixture of a polymer having active energy ray curability and a polymer not having active energy ray curability, a polymer having active energy ray curability and a polyfunctional monomer having active energy ray curability and /. Alternatively, it may be a mixture with an oligomer, or a mixture of these three types.

Among the above, from the viewpoint of easily obtaining a pressure-sensitive adhesive that exhibits cohesive power while maintaining adhesiveness, a mixture of a polymer having no active energy ray-curable property and an active energy ray-curable polyfunctional monomer and / or oligomer. Is preferable, and in particular, a mixture of a polymer having no active energy ray-curable property and an active energy ray-curable polyfunctional monomer as a main component is preferable.

As the polymer having no active energy ray-curable property, a (meth) acrylic acid ester polymer having no active energy ray-curable group (hereinafter, may be referred to as “(meth) acrylic acid ester polymer (X)”). Is preferable. The (meth) acrylic acid ester polymer (X) preferably contains a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms as a monomer constituting the polymer. Thereby, the obtained pressure-sensitive adhesive can exhibit preferable stickiness. Further, the (meth) acrylic acid ester polymer (X) contains a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms and a monomer having a reactive functional group (reactive functional group-containing monomer). And, if desired, it is a copolymer with another monomer used. When the (meth) acrylic acid ester polymer (X) contains a reactive functional group-containing monomer as a monomer constituting the polymer, the adhesion to the glass surface of a liquid crystal cell or the like can be improved. It is also possible to form a crosslinked structure by reacting with a crosslinking agent (Z) described later.

Examples of the (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms include methyl (meth) acrylic acid, ethyl (meth) acrylic acid, propyl (meth) acrylic acid, and n- (meth) acrylic acid. Butyl, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-decyl (meth) acrylate, (meth) acrylate Examples thereof include n-dodecyl, myristyl (meth) acrylate, palmityl (meth) acrylate, and stearyl (meth) acrylate. Among them, from the viewpoint of further improving the adhesiveness, a (meth) acrylic acid ester having an alkyl group having 1 to 8 carbon atoms is preferable, and n-butyl (meth) acrylic acid is particularly preferable. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester polymer (X) preferably contains 50% by mass or more of the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms of the alkyl group as the monomer unit constituting the polymer. In particular, it is preferably contained in an amount of 60% by mass or more, and more preferably 70% by mass or more. Further, it is preferable that the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms of the alkyl group is contained in an amount of 99% by mass or less, and particularly preferably 98% by mass or less.

Examples of the reactive functional group-containing monomer include a monomer having a hydroxyl group in the molecule (hydroxyl group-containing monomer), a monomer having a carboxyl group in the molecule (carboxyl group-containing monomer), and a monomer having an amino group in the molecule (amino group-containing monomer). Monomer) and the like are preferably mentioned. These reactive functional group-containing monomers may be used alone or in combination of two or more.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and (meth). ) Acrylic acid hydroxyalkyl esters such as 3-hydroxybutyl acrylate and 4-hydroxybutyl (meth) acrylic acid can be mentioned.

Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. Of these, acrylic acid is preferable from the viewpoint of reactivity of the obtained (meth) acrylic acid ester polymer (X) with the cross-linking agent (Z) of the carboxyl group and copolymerizability with other monomers. These may be used alone or in combination of two or more.

Examples of the amino group-containing monomer include aminoethyl (meth) acrylate and n-butylaminoethyl (meth) acrylate. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester polymer (X) preferably contains 1% by mass or more of a reactive functional group-containing monomer, and particularly preferably 2% by mass or more, as a monomer unit constituting the polymer. .. Further, the reactive functional group-containing monomer is preferably contained in an amount of 25% by mass or less, particularly preferably 20% by mass or less, and further preferably 5% by mass or less.

The polymerization mode of the (meth) acrylic acid ester polymer (X) may be a random copolymer or a block copolymer.

The weight average molecular weight of the (meth) acrylic acid ester polymer (X) is preferably 300,000 or more, particularly preferably 1 million or more, and further preferably 1.6 million or more. The weight average molecular weight is preferably 3 million or less, particularly preferably 2.5 million or less, and further preferably 2.2 million or less.

In the adhesive composition P, one type of (meth) acrylic acid ester polymer (X) may be used alone, or two or more types may be used in combination.

As the active energy ray-curable polyfunctional monomer, a polyfunctional acrylate-based monomer having a molecular weight of 1000 or less, which has excellent compatibility with the (meth) acrylic acid ester polymer (X) and the like, is preferable.

Examples of the polyfunctional acrylate-based monomer having a molecular weight of 1000 or less include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and polyethylene glycol di. (Meta) acrylate, neopentyl glycol adipate di (meth) acrylate, neopentyl glycol di (meth) acrylate, dicyclopentanyldi (meth) acrylate, caprolactone-modified dicyclopentenyldi (meth) acrylate, ethylene oxide-modified Bifunctional types such as di (meth) acrylate, di (acryloxyethyl) isocyanurate, and allylated cyclohexyl di (meth) acrylate; trimethylpropantri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propion. Acid-modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide-modified trimethylol propanetri (meth) acrylate, tris (acryloxyethyl) isocyanurate, ε-caprolactone-modified tris- (2-( Trifunctional type such as meta) acryloxyethyl) isocyanurate; tetrafunctional type such as diglycerin tetra (meth) acrylate and pentaerythritol tetra (meth) acrylate; pentafunctional type such as propionic acid-modified dipentaerythritol penta (meth) acrylate Types: Hexa-functional types such as dipentaerythritol hexa (meth) acrylate and caprolactone-modified dipentaerythritol hexa (meth) acrylate can be mentioned. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the active energy ray-curable compound (Y) is preferably 1 part by mass or more, particularly 5 parts by mass or more, with respect to 100 parts by mass of the (meth) acrylic acid ester polymer (X). Is preferable, and more preferably 10 parts by mass or more. The content is preferably 50 parts by mass or less, particularly preferably 30 parts by mass or less, and further preferably 20 parts by mass or less.

The active energy ray-curable pressure-sensitive adhesive preferably contains a cross-linking agent (Z). When the active energy ray-curable pressure-sensitive adhesive contains a (meth) acrylic acid ester polymer (X) containing a reactive functional group-containing monomer as a monomer unit constituting the polymer and a cross-linking agent (Z). When the pressure-sensitive adhesive is heated or the like, the cross-linking agent (Z) reacts with the reactive functional groups of the reactive functional group-containing monomer constituting the (meth) acrylic acid ester polymer (X). As a result, a structure in which the (meth) acrylic ester polymer (X) is crosslinked by the cross-linking agent (Z) is formed, and the cohesive force of the obtained pressure-sensitive adhesive is improved.

The cross-linking agent (Z) may be any as long as it reacts with the reactive functional group of the (meth) acrylic acid ester polymer (X). For example, an isocyanate-based cross-linking agent, an epoxy-based cross-linking agent, and an amine-based cross-linking agent. , Melamine-based cross-linking agent, aziridine-based cross-linking agent, hydrazine-based cross-linking agent, aldehyde-based cross-linking agent, oxazoline-based cross-linking agent, metal alkoxide-based cross-linking agent, metal chelate-based cross-linking agent, metal salt-based cross-linking agent, ammonium salt-based cross-linking agent, etc. Can be mentioned. As the isocyanate-based cross-linking agent, the same cross-linking agent (B) as described above can be used. The cross-linking agent (Z) may be used alone or in combination of two or more.

The content of the cross-linking agent (Z) is preferably 0.01 part by mass or more, and particularly 0.05 part by mass or more with respect to 100 parts by mass of the (meth) acrylic ester polymer (X). Is preferable, and more preferably 0.1 parts by mass or more. The content is preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and further preferably 1 part by mass or less.

If desired, the active energy ray-curable pressure-sensitive adhesive may include various additives such as a photopolymerization initiator, a silane coupling agent, a refractive index adjuster, an antistatic agent, a tackifier, an antioxidant, an ultraviolet absorber, and light. Stabilizers, softeners, fillers and the like may be included.

When ultraviolet rays are used as the active energy rays for curing the active energy ray-curable pressure-sensitive adhesive, the active energy ray-curable pressure-sensitive adhesive preferably contains a photopolymerization initiator.

Examples of the photopolymerization initiator include benzoine, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, and the like. 2,2-Diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenylketone, 2-methyl-1- [4- (methylthio) phenyl]- 2-morpholino-propane-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2 -Methylanthraquinone, 2-ethylanthraquinone, 2-tershary-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, Benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoic acid ester, oligo [2-hydroxy-2-methyl-1 [4- (1-methylvinyl) phenyl] propanone], 2,4,6-trimethylbenzoyl- Examples thereof include diphenyl-phosphine oxide. These may be used alone or in combination of two or more.

The amount of the photopolymerization initiator used shall be 0.1 part by mass or more, particularly 1 part by mass or more, with respect to 100 parts by mass of the active energy ray-curable compound (Y) in the active energy ray-curable pressure-sensitive adhesive. Is preferable. The amount used is preferably 20 parts by mass or less, particularly preferably 12 parts by mass or less.

Further, the active energy ray-curable pressure-sensitive adhesive preferably contains a silane coupling agent from the viewpoint of improving the adhesion of the obtained pressure-sensitive adhesive to the film. The silane coupling agent is preferably an organosilicon compound having at least one alkoxysilyl group in the molecule, which has good compatibility with the adhesive component and has light transmittance.

Examples of such a silane coupling agent include the above-mentioned epoxy group-containing silane coupling agent (D1) and mercapto group-containing silane coupling agent (D2), as well as vinyltrimethoxysilane, vinyltriethoxysilane, and methacryloxypropyltri. Polymerizable unsaturated group-containing silicon compounds such as methoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-amino Amino group-containing silicon compounds such as propylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-isopropylpropyltriethoxysilane, or at least one of these, methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, Examples thereof include a condensate with an alkyl group-containing silicon compound such as ethyltrimethoxysilane. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the silane coupling agent is preferably 0.01 part by mass or more, particularly 0.05 part by mass or more, with respect to 100 parts by mass of the (meth) acrylic acid ester polymer (X). It is preferable, and more preferably 0.1 part by mass or more. The content is preferably 10 parts by mass or less, particularly preferably 5 parts by mass or less, and further preferably 1 part by mass or less.

The polymer having active energy ray curability is a (meth) acrylic acid ester (co) polymer in which a functional group having active energy ray curability (active energy ray curable group) is introduced into the side chain. Is preferable.

The thickness of the second pressure-sensitive adhesive layer 26 is preferably 1 μm or more, and particularly preferably 2 μm or more. The thickness is usually 50 μm or less, preferably 20 μm or less, and particularly preferably 7 μm or less. If the pressure-sensitive adhesive layer is too thin, the adhesiveness is lowered, and if it is too thick, problems such as the pressure-sensitive adhesive sticking out are likely to occur.

(4) Polarizer As the polarizer 21, the same one as the polarizer 21 of the polarizing plate 2A described above can be used.

(5) Protective layer The protective layer 27 is preferably made of a transparent resin film. As the protective layer 27, the same one as the first protective layer 22 in the polarizing plate 2A can be used.

(6) Adhesive Layer The adhesive layer that may be interposed between the polarizer 21 and the protective layer 27 and / or between the polarizer 21 and the second retardation plate 25 is the above-mentioned polarizing plate 2A. The same as the adhesive layer of can be used.

(7) Method for manufacturing composite polarizing plate The composite polarizing plate 2B can be manufactured by a usual method. Hereinafter, as an example, a manufacturing method when a water-based adhesive is used as the adhesive will be described.

First, a coating film of the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer 26 is formed on the peel-off surface of the release sheet. Specifically, the coating liquid of the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer 26 is applied to the peeling surface of the release sheet and dried.

On the other hand, an adhesive layer is formed on the bonding surface of the polarizer 21 or the bonding surface of the second retardation plate 25 and the protective layer 27. The formation of the adhesive layer can be performed in the same manner as the method in the method for producing the polarizing plate 2A described above. The same applies to the thickness of the adhesive layer and the easy-adhesion treatment.

After the adhesive layer is formed as described above, the protective layer 27 is bonded to one surface of the polarizer 21 via the adhesive layer, and the second retardation plate 25 is attached to the other surface of the polarizer 21. A laminated body composed of a protective layer 27, a polarizing element 21, and a second retardation plate 25 is obtained by bonding to the surface of the above.

Next, a coating film of the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer 26 on the release sheet is bonded to the surface of the obtained laminate on the side of the second retardation plate 25. Then, the active energy ray is irradiated through the release sheet to cure the coating film of the pressure-sensitive adhesive, and the coating film is used as the second pressure-sensitive adhesive layer 26.

Here, the active energy beam refers to an electromagnetic wave or a charged particle beam having an energy quantum, and specific examples thereof include an ultraviolet ray and an electron beam. Among the active energy rays, ultraviolet rays, which are easy to handle, are particularly preferable.

The irradiation of ultraviolet rays can be performed by a high-pressure mercury lamp, a metal halide lamp, a fusion H lamp, a xenon lamp, or the like, and the irradiation amount of ultraviolet rays is preferably about ^{50 to 1000 mW / cm 2.} Further, the light quantity is preferably 50~10000mJ / cm ^2, more preferably 80~5000mJ / cm ^2, and particularly preferably 100~1000mJ / cm ^2. On the other hand, the irradiation of the electron beam can be performed by an electron beam accelerator or the like, and the irradiation amount of the electron beam is preferably about 10 to 1000 grad.

Finally, the release sheet is peeled off from the second pressure-sensitive adhesive layer 26 formed above, and the second acrylic resin layer 243 in the first retardation plate 24 is opposed to the exposed second pressure-sensitive adhesive layer 26. Stick the sides together. In this way, a composite polarizing plate 2B formed by laminating a protective layer 27, a polarizing element 21, a second retardation plate 25, a second pressure-sensitive adhesive layer 26, and a first retardation plate 24 is obtained.

The total thickness of the composite polarizing plate 2B is preferably 20 μm or more, more preferably 30 μm or more, and particularly preferably 50 μm or more. The total thickness is preferably 300 μm or less, more preferably 150 μm or less, and particularly preferably 100 μm or less.

(8) Method for Manufacturing Optical Film with Adhesive Layer As a preferable example of the method for manufacturing the optical film 10B with a pressure-sensitive adhesive layer, first, a release sheet is formed on one or both sides of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition P. To manufacture an adhesive sheet made by laminating. Here, as an example, it is assumed that a pressure-sensitive adhesive sheet formed by laminating release sheets on both sides of the pressure-sensitive adhesive layer is manufactured. This pressure-sensitive adhesive sheet can be manufactured by the method described in the method for manufacturing the optical film 10A with a pressure-sensitive adhesive layer.

One of the release sheets (light release type release sheet) is peeled from the adhesive sheet obtained as described above. Then, the first retardation plate 24 of the composite polarizing plate 2B is superposed on the exposed pressure-sensitive adhesive layer, and the pressure-sensitive adhesive sheet and the composite polarizing plate 2B are pressure-bonded. As a result, the optical film 10B with an adhesive layer (with a release sheet) can be obtained.

As another example of the method for producing the optical film 10B with an adhesive layer, the above-mentioned coating solution of the adhesive composition P is applied to the peeled surface of the release sheet, and heat treatment is performed to form a coating film. The first retardation plate 24 of the composite polarizing plate 2B is superposed on the coating film. When the curing period is required, the curing period is set, and when the curing period is not required, the coating film becomes the adhesive layer 1 as it is. As a result, the optical film 10B with an adhesive layer (with a release sheet) can be obtained.

3. 3. Physical Properties of Optical Film with Adhesive Layer The adhesive strength of the optical films 10A and 10B with an adhesive layer according to the present embodiment is that the adhesive strength to non-alkali glass is 0.5 N / 25 mm or more from the viewpoint of durability. Is preferable, and 1N / 25 mm or more is particularly preferable. Further, the adhesive strength is preferably 20 N / 25 mm or less, particularly preferably 10 N / 25 mm or less, and further preferably 7 N / 25 mm or less from the viewpoint of reworkability. The adhesive strength referred to here basically refers to the adhesive strength measured by the 180 ° peeling method according to JIS Z0237: 2009, but the measurement sample is 25 mm wide and 100 mm long, and the measurement sample is adhered. After applying pressure to the body at 0.5 MPa and 50 ° C. for 20 minutes, leaving it for 24 hours under the conditions of normal pressure, 23 ° C. and 50% RH, and then measuring at a peeling speed of 300 mm / min. To do. When the adhesive strength is within the above range, it is possible to prevent floating and peeling when the liquid crystal cell is attached to the liquid crystal cell while maintaining excellent reworkability.

Further, the optical films 10A and 10B with an adhesive layer according to the present embodiment have adhesive strength after being attached to the adherend and further left at 23 ° C. and 50% RH for 14 days (14 days after application). Adhesive strength) is preferably 1N / 25 mm or more, and particularly preferably 3N / 25 mm or more. The adhesive strength is preferably 20 N / 25 mm or less, and particularly preferably 9 N / 25 mm or less. By suppressing the increase in adhesive strength with time in this way, the optical films 10A and 10B with an adhesive layer according to the present embodiment are also excellent in reworkability, and can be easily reattached even after being attached to the liquid crystal cell. be able to.

The surface resistivity of the pressure-sensitive adhesive layer in the optical films 10A and 10B with a pressure-sensitive adhesive layer according to the present embodiment is preferably 1.0 × 10 ¹² Ω / sq or less, and particularly 1.0 × 10 ¹¹ Ω / sq. It is preferably 1.0 × 10 ¹⁰ Ω / sq or less, and more preferably 1.0 × 10 10 Ω / sq or less. When the surface resistivity is not more than the above value, sufficient antistatic property can be exhibited in the display panel. Such surface resistivity is determined by the fact that the (meth) acrylic acid ester copolymer (A) contains the oxyalkylene group-containing monomer (a3) as the monomer unit constituting the polymer, whereby the adhesive composition P contains the oxyalkylene group-containing monomer (a3). Even if the content of the antistatic agent (C) in the above is relatively small, it can be achieved. The surface resistivity of the pressure-sensitive adhesive layer shall be measured according to JIS K6911, specifically as shown in a test example described later. The lower limit of the surface resistivity is not particularly limited, a viewpoint from 5.0 × 10 approximately ⁸ Omega / sq and does not adversely affect the durability and heat uneven resistance.

4. Use of Optical Film with Adhesive Layer By using the optical films 10A and 10B with the adhesive layer, for example, a liquid crystal display device including a liquid crystal cell and an optical film (polarizing plate or composite polarizing plate) can be manufactured. it can.

Specifically, the pressure-sensitive adhesive layers of the optical films 10A and 10B with the pressure-sensitive adhesive layer (in the case where the release sheets are laminated, the pressure-sensitive adhesive layer exposed by peeling the release sheets) are desired for the liquid crystal cell. It may be overlapped with respect to the surface and crimped. As a result, a liquid crystal display device including the liquid crystal cell and the polarizing plate 2A and / or the composite polarizing plate 2B can be obtained.

Since the pressure-sensitive adhesive layer 1 of the optical films 10A and 10B with a pressure-sensitive adhesive layer according to the present embodiment is excellent in stress relaxation property and adhesion to an acrylic resin, the obtained liquid crystal display device is subjected to high temperature conditions and moist heat conditions. Alternatively, even under heat shock, the occurrence of floating or peeling at the interface of the pressure-sensitive adhesive layer 1 is suppressed. For example, when a glass plate to which optical films 10A and 10B with an adhesive layer are attached is left under high temperature conditions of 85 ° C., moist heat conditions of 60 ° C. and 90% RH for 250 hours, or heat of -35 ° C. to 70 ° C. Even when a shock (30 minutes each, 200 cycles) is applied, the occurrence of floating and peeling is suppressed.

Further, since the pressure-sensitive adhesive layer 1 of the optical films 10A and 10B with the pressure-sensitive adhesive layer according to the present embodiment is also excellent in stress relaxation property, the obtained liquid crystal display device is hard to warp even under high temperature conditions, and further, heat unevenness Is unlikely to occur. For example, even when the glass plate to which the optical films 10A and 10B with the adhesive layer are attached is left under high temperature conditions (for example, under the conditions of 80 to 85 ° C.) for 250 hours, it is difficult to warp and heat unevenness is unlikely to occur. In particular, even if the polarizing plate 2A or the composite polarizing plate 2B is a thin film, the liquid crystal display device is unlikely to warp, and even if the liquid crystal cell is a high-definition one, thermal unevenness is unlikely to occur.

Further, since the pressure-sensitive adhesive layer 1 of the optical films 10A and 10B with the pressure-sensitive adhesive layer according to the present embodiment is also excellent in antistatic property, static electricity is generated when the release sheet is peeled off from the pressure-sensitive adhesive layer 1, for example. It becomes difficult to occur. Therefore, for example, when the optical films 10A and 10B with an adhesive layer from which the release sheet has been peeled off are attached to the liquid crystal cell, it is possible to suppress adverse effects on the liquid crystal cell. In addition, it is possible to prevent dust and dirt from being attracted to the optical films 10A and 10B with an adhesive layer due to static electricity.

A transparent conductive film may be present on the surface of the liquid crystal cell with which the pressure-sensitive adhesive layer 1 is in contact. Examples of such transparent conductive film include metals such as platinum, gold, silver and copper, oxides such as tin oxide, indium oxide, cadmium oxide, zinc oxide and zinc dioxide, tin-doped indium oxide (ITO) and zinc oxide-doped oxidation. Examples include composite oxides such as indium, fluorine-doped indium oxide, antimony-doped tin oxide, fluorine-doped tin oxide, and aluminum-doped zinc oxide, and non-oxidizing compounds such as chalcogenide, lanthanum hexaborate, titanium nitride, and titanium carbide. Be done.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Example 1]
1. 1. Manufacture of Optical Film (Composite Polarizing Plate) (1) Preparation of Polarizer A 75 μm-thick polyvinyl alcohol film made of polyvinyl alcohol having an average degree of polymerization of about 2,400 and a saponification degree of 99.9 mol% or more is dried. The film was uniaxially stretched about 5 times and immersed in pure water at 60 ° C. for 1 minute while maintaining a tense state. Then, it was immersed in an aqueous solution having a mass ratio of iodine / potassium iodide / water of 0.05 / 5/100 at 28 ° C. for 60 seconds. Subsequently, it was immersed in an aqueous solution having a mass ratio of potassium iodide / boric acid / water of 8.5 / 8.5 / 100 at 72 ° C. for 300 seconds. Then, it was washed with pure water at 26 ° C. for 20 seconds and then dried at 65 ° C. to obtain a polarizer in which iodine was adsorbed and oriented on polyvinyl alcohol.

(2) Preparation of Laminated Body Containing Protective Layer, Polarizer and Second Phase Difference Plate To 100 parts by mass of water, 3 carboxyl group-modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name "KL-318") was added. A polyamide epoxy-based additive (manufactured by Taoka Chemical Industry Co., Ltd., trade name "Smiley's Resin 650 (30)", aqueous solution having a solid content concentration of 30% by mass), which is a water-soluble epoxy resin, is added to the aqueous solution by dissolving parts by mass. An epoxy adhesive was prepared by adding 1.5 parts by mass. The epoxy adhesive was applied to one surface of the polarizer obtained above.

A 25 μm-thick triacetyl cellulose film (manufactured by Konica Minolta Opto Co., Ltd., trade name “KC2UA”) with a saponified surface is attached to the coating layer of the epoxy adhesive as a protective layer. Then, a laminated body formed by laminating a protective layer and a polarizer was obtained.

Next, an epoxy adhesive is applied to the other surface of the polarizer in the laminate in the same manner as described above, and a cyclic olefin resin having a thickness of 23 μm is applied to the coated layer as a second retardation plate. A zero retardation film made of (manufactured by Nippon Zeon Co., Ltd., trade name "ZEONOR") was attached. Then, the protective layer and the second retardation plate were adhered to the polarizer by drying at 80 ° C. for 5 minutes. After bonding, it is cured at 40 ° C. for 168 hours, and a protective layer (layer thickness 25 μm), a polarizer (stretching magnification 5 times, layer thickness 15 μm) and a second retardation plate (layer thickness 23 μm) are laminated to form a total thickness. A 63 μm laminate was obtained.

(3) Formation of coating film of active energy ray-curable pressure-sensitive adhesive A (meth) acrylic acid ester polymer (X) was prepared by copolymerizing 95 parts by mass of n-butyl acrylate and 5 parts by mass of acrylic acid. When the molecular weight of this (meth) acrylic acid ester polymer (X) was measured by the method described later, the weight average molecular weight (Mw) was 2 million.

As the above (meth) acrylic acid ester polymer (X) 100 parts by mass and the active energy ray-curable compound (Y) (polyfunctional monomer), tris (acryloxyethyl) isocyanurate (manufactured by Toa Synthetic Co., Ltd., trade name " Aronix M-315 ") 15 parts by mass, as a cross-linking agent (Z), 0.3 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name" Coronate L "), and as a polymerization initiator , Benzophenone and 1-hydroxycyclohexylphenylketone in a 1: 1 mass ratio mixture (manufactured by Ciba Specialty Chemicals, trade name "Irgacure 500") and 1.5 parts by mass, and 3-as a silane coupling agent. Active energy ray-curable adhesive by mixing 0.2 parts by mass of glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Industry Co., Ltd., trade name "KBM403"), stirring well, and diluting with ethyl acetate. A coating solution of the agent was obtained.

The obtained coating solution of the active energy ray-curable pressure-sensitive adhesive was applied to the peel-treated surface of a peel-off sheet (Lintec Corporation, SP-PET3811, thickness: 38 μm) in which one side of a polyethylene terephthalate film was peel-treated with a silicone-based release agent. After coating with a knife coater, the film was heat-treated at 90 ° C. for 1 minute to form a coating film of an active energy ray-curable pressure-sensitive adhesive.

(4) Preparation of First Phase Difference Plate A methacrylic resin containing approximately 20% by mass of acrylic rubber particles having an average particle size of 200 nm constituting the first acrylic resin layer (manufactured by Sumitomo Chemical Co., Ltd., The product name "Technoloy S001"), the styrene-maleic anhydride-based copolymer resin (manufactured by Nova Chemical Co., Ltd., product name "Dylark D332") constituting the phase difference expression layer, and the second acrylic resin layer. A methacrylic resin (manufactured by Sumitomo Chemical Co., Ltd., trade name "Technoloy S001") containing about 20% by mass of acrylic rubber particles having an average particle size of 200 nm is coextruded in this order in three layers to form a three-layer structure. Laminated film was obtained. The obtained laminated film is stretched to form a first retardation plate having an in-plane retardation value of 60 nm and a thickness of 25 μm (first acrylic resin layer / retardation developing layer / second acrylic resin layer). Got

(5) Preparation of Composite Polarizing Plate A coating film of the active energy ray-curable pressure-sensitive adhesive obtained in the above step (3) is formed on the surface of the laminate obtained in the above step (2) on the side of the second retardation plate. And irradiated the release sheet with ultraviolet rays under the following conditions to cure the coating film of the pressure-sensitive adhesive to form a second pressure-sensitive adhesive layer. Then, the release sheet is peeled off from the obtained second pressure-sensitive adhesive layer, and the surface of the exposed second pressure-sensitive adhesive layer is exposed to the second in the first retardation plate obtained in the above step (4). The surface on the acrylic resin layer side was bonded. In this way, a composite polarizing plate (optical film) having a total thickness of 93 μm was obtained by laminating a protective layer, a polarizing element, a second retardation plate, a second pressure-sensitive adhesive layer, and a first retardation plate. .. The thickness of the formed second pressure-sensitive adhesive layer was 5 μm.
<Ultraviolet irradiation conditions>
・ Uses high-pressure mercury lamp ・ Illuminance 300mW / cm ² , light intensity 300mJ / cm ²
・ UV illuminance / photometer uses "UVPF-A1" manufactured by iGraphics.

2. 2. Production of optical film with pressure-sensitive adhesive layer (1) Preparation of (meth) acrylic acid ester copolymer 62 parts by mass of n-butyl acrylate, 10 parts by mass of 2-methoxyethyl acrylate, 5 parts by mass of isobornyl acrylate, acrylic acid A (meth) acrylic acid ester copolymer (A) was prepared by copolymerizing 20 parts by mass of 2-phenylethyl and 3 parts by mass of 2-hydroxyethyl acrylate. When the molecular weight of this (meth) acrylic acid ester copolymer (A) was measured by the method described later, the weight average molecular weight (Mw) was 1.6 million. From the above formulation, the hydroxyl value of the (meth) acrylic acid ester copolymer (A) is calculated to be 14.49 mgKOH / g, and the acid value is calculated to be 0 mgKOH / g.

(2) Preparation of Adhesive Composition 100 parts by mass of the (meth) acrylic acid ester copolymer (A) obtained in the above step (1) and trimethylolpropane-modified xylylene diisocyanate as a cross-linking agent (B) ( Mitsui Chemicals, Inc., trade name "Takenate D110N") 0.2 parts by mass, and N-octyl-4-methylpyridinium hexafluorophosphate (an ionic compound solid at room temperature) 5.0 as an antioxidant (C) 0.2 parts by mass, 0.2 parts by mass of 3-glycidoxypropyltrimethoxysilane (manufactured by Shinetsu Chemical Industry Co., Ltd., trade name "KBM403") as an epoxy group-containing silane coupling agent (D1), and a mercapto group-containing silane cup. As a ring agent (D2), a cocondensate of 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane (manufactured by Shinetsu Chemical Industry Co., Ltd., trade name "X-41-1810", mercapto equivalent: 450 g / mol) 0. 2 parts by mass were mixed, thoroughly stirred, and diluted with ethyl acetate to obtain a coating solution of the adhesive composition.

Here, Table 1 shows each formulation (solid content conversion value) of the adhesive composition when the (meth) acrylic acid ester copolymer (A) is 100 parts by mass (solid content conversion value). Details of the abbreviations and the like shown in Table 1 are as follows.
[(Meta) acrylic acid ester copolymer (A)]
BA: n-butyl acrylate MEA: 2-methoxyethyl acrylate IBXA: isobornyl acrylate PhEA: 2-phenylethyl acrylate HEA: 2-hydroxyethyl acrylate MA: methyl acrylate
[Crosslinking agent (B)]
XDI: Trimethylolpropane-modified xylylene diisocyanate (manufactured by Mitsui Chemicals, trade name "Takenate D110N")
[Antistatic agent (C)]
Pry + PF6-: N-octyl-4-methylpyridinium hexafluorophosphate (ionic compound solid at room temperature)
K + FSI-: Potassium N, N-bis (fluorosulfonyl) imide (ionic compound solid at room temperature; manufactured by Mitsubishi Materials Electronics Co., Ltd., trade name "K-FSI")
Pry + FSI-: N-decylpyridinium bis (fluorosulfonyl) imide (ionic compound solid at room temperature)

(3) Preparation of Optical Film with Adhesive Layer A release sheet (manufactured by Lintec Corporation, SP-PET3811, thickness) obtained by peeling the coating solution of the obtained adhesive composition on one side of a polyethylene terephthalate film with a silicone-based release agent. : 38 μm) was applied to the peeled surface with a knife coater, and then heat-treated at 90 ° C. for 1 minute to form a coating film of an adhesive composition.

Next, the composite polarizing plate obtained above was bonded to the coating film so that the surface of the first acrylic resin layer on the first retardation plate and the exposed surface of the coating film were in contact with each other. By curing at 23 ° C. and 50% RH for 7 days, an optical film with an adhesive layer having an adhesive layer formed on the composite polarizing plate was obtained. The thickness of the formed pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer) was 20 μm.

[Examples 2-9, Comparative Examples 1-2]
Table 1 shows the types and proportions of the monomers constituting the (meth) acrylic acid ester copolymer (A), the blending amount of the cross-linking agent (B), and the type and blending amount of the antistatic agent (C). An optical film with an adhesive layer was produced in the same manner as in Example 1 except for modification.

[Reference Example 1]
(1) Preparation of Polarizer A 75 μm-thick polyvinyl alcohol film made of polyvinyl alcohol having an average degree of polymerization of about 2,400 and a saponification degree of 99.9 mol% or more is uniaxially stretched about three times by a dry method, and further. The film was immersed in pure water at 60 ° C. for 1 minute while maintaining a tense state. Then, it was immersed in an aqueous solution having a mass ratio of iodine / potassium iodide / water of 0.05 / 5/100 at 28 ° C. for 60 seconds. Subsequently, it was immersed in an aqueous solution having a mass ratio of potassium iodide / boric acid / water of 8.5 / 8.5 / 100 at 72 ° C. for 300 seconds. Then, it was washed with pure water at 26 ° C. for 20 seconds and then dried at 65 ° C. to obtain a polarizer in which iodine was adsorbed and oriented on polyvinyl alcohol.

(2) Preparation of Plate Plate 3 parts by mass of carboxyl group-modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name "KL-318") is dissolved in 100 parts by mass of water, and a water-soluble epoxy resin is dissolved in the aqueous solution. An epoxy adhesive was prepared by adding 1.5 parts by mass of a polyamide epoxy additive (manufactured by Taoka Chemical Industry Co., Ltd., trade name "Smiley's Resin 650 (30)", an aqueous solution having a solid content concentration of 30% by mass). .. The epoxy adhesive was applied to one surface of the polarizer obtained above.

A triacetyl cellulose film having a thickness of 80 μm (manufactured by Konica Minolta Opto Co., Ltd., trade name “KC8UYW”) having a surface saponified treatment as a first protective layer with respect to the coating layer of the epoxy adhesive. Was pasted together. Similarly, as a second protective layer, a triacetyl cellulose film having a thickness of 80 μm (manufactured by Konica Minolta Opto Co., Ltd., trade name “KC8UYW”) was attached to the other surface of the polarizer.

Then, the first protective layer and the second protective layer were adhered to the polarizer by drying at 80 ° C. for 5 minutes. After bonding, it is cured at 40 ° C. for 168 hours, and the first protective layer (layer thickness 80 μm), the polarizer (stretching magnification 3 times, layer thickness 25 μm) and the second protective layer (layer thickness 80 μm) are laminated. A polarizing plate having a total thickness of 185 μm was obtained.

Next, an adhesive layer was formed on one surface of the polarizing plate obtained in the above step in the same manner as in Comparative Example 1. As a result, an optical film with an adhesive layer whose surface in contact with the adhesive layer was made of triacetyl cellulose was obtained.

Here, the above-mentioned weight average molecular weight (Mw) is a polystyrene-equivalent weight average molecular weight measured under the following conditions (GPC measurement) using gel permeation chromatography (GPC).
<Measurement conditions>
-GPC measuring device: HLC-8020 manufactured by Tosoh Corporation
-GPC column (passed in the following order): TSK guard volume HXL-H manufactured by Tosoh Corporation
TSK gel GMHXL (x2)
TSK gel G2000HXL
-Measurement solvent: tetrahydrofuran-Measurement temperature: 40 ° C

[Test Example 1] (Measurement of gel fraction)
A release sheet (manufactured by Lintec Corporation, SP-) in which one side of a polyethylene terephthalate film was peeled off with a silicone-based release agent instead of the optical film used for producing the optical film with an adhesive layer in Examples, Comparative Examples and Reference Examples. A pressure-sensitive adhesive sheet was prepared using PET3801, thickness: 38 μm). Specifically, the release sheet is brought into contact with the release treatment surface side on the exposed coating film of the composition composed of the release sheet / adhesive composition coating film obtained in the manufacturing process of Examples or Comparative Examples. They were laminated and cured for 7 days under the conditions of 23 ° C. and 50% RH. As a result, a pressure-sensitive adhesive sheet having a structure of a release sheet (SP-PET3801) / adhesive layer (thickness: 20 μm) / release sheet (SP-PET3811) was produced.

The obtained adhesive sheet is cut into a size of 80 mm × 80 mm, the adhesive layer is wrapped in a polyester mesh (mesh size 200), the mass is weighed with a precision balance, and the mass of the mesh alone is subtracted. The mass of the adhesive alone was calculated. The mass at this time is M1.

Next, the pressure-sensitive adhesive wrapped in the polyester mesh was immersed in ethyl acetate at room temperature (23 ° C.) for 24 hours. Then, the adhesive was taken out, air-dried for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 50%, and further dried in an oven at 80 ° C. for 12 hours. After drying, the mass was weighed with a precision balance, and the mass of the adhesive alone was calculated by subtracting the mass of the mesh alone. The mass at this time is M2. The gel fraction (%) is represented by (M2 / M1) × 100. The results are shown in Table 2.

[Test Example 2] (Durability evaluation)
The optical films with an adhesive layer obtained in Examples, Comparative Examples and Reference Examples were cut to prepare a sample having a size of 150 mm × 200 mm. The release sheet is peeled off from this sample, attached to non-alkali glass (Corning Inc., trade name "Eagle-XG") via an exposed adhesive layer, and then 0.5 MPa, 50 ° C. in an autoclave manufactured by Kurihara Seisakusho. Then, the pressure was applied for 20 minutes.

Then, it was put into an environment of the following three durable conditions, and after 250 hours, the presence or absence of floating or peeling was confirmed using a 10-fold loupe. The evaluation criteria are as follows. The results are shown in Table 2.
⊚: No floating or peeling was confirmed.
◯: Floating or peeling with a size of 0.5 mm or less was confirmed.
Δ: Floating or peeling with a size of more than 0.5 mm and 1.0 mm or less was confirmed.
X: Floating or peeling with a size of more than 1.0 mm was confirmed.
<Durability condition>
・ Heat resistance: 85 ° C dry
Moist heat: 60 ° C, relative humidity 90% RH
・ H. S. : Heat shock test for 30 minutes each at -35 ° C ⇔ 70 ° C, 200 cycles

[Test Example 3] (Evaluation of warpage resistance)
The optical films with an adhesive layer obtained in Examples, Comparative Examples, and Reference Examples were cut so as to have a length of 200 mm and a width of 150 mm. The release sheet is peeled off from the optical film with the adhesive layer, and the exposed adhesive layer is placed in the center of non-alkali glass (manufactured by Corning Inc., trade name "Eagle-XG") having a length of 250 mm, a width of 175 mm, and a thickness of 0.5 mm. It was pasted on the part and used as a sample. This sample was left at 85 ° C. in a dry atmosphere for 250 hours. After that, it is taken out in an environment of 25 ° C. and 50% RH, placed on a horizontal table with the polarizing plate side facing up, and the amount of warpage (distance between the corners and the table) from the table at each corner (4 points) of the sample. ) Was measured, and the amount of warpage at each corner was totaled. Based on the results, the warpage resistance was evaluated as follows. The results are shown in Table 2.
⊚: Total amount of warp is 10 mm or less ○: Total amount of warp is more than 10 mm, 15 mm or less Δ: Total amount of warp is more than 15 mm, 20 mm or less ×: Total amount of warp is more than 20 mm

[Test Example 4] (Evaluation of heat unevenness)
The optical film with an adhesive layer obtained in Examples, Comparative Examples and Reference Examples was adjusted to a size of 200 mm × 150 mm using a cutting device (Super Cutter manufactured by Ogino Seisakusho Co., Ltd., PN1-600). The release sheet was peeled off and attached to non-alkali glass (Eagle XG manufactured by Corning Inc.) via an exposed adhesive layer, and then pressurized at 0.5 MPa and 50 ° C. for 20 minutes in an autoclave manufactured by Kurihara Seisakusho. The above bonding was performed by applying an optical film with an adhesive layer on the front and back of the non-alkali glass so that the polarization axes were in a cross-nicol state (polarization axes: ∠45 °, ∠135 °). In this state, after leaving it for 250 hours in an environment of 80 ° C. dry, it was left for 2 hours in an environment of 23 ° C. and 50% RH, and using this as a sample, the heat resistance unevenness was evaluated by the method shown below. The results are shown in Table 2.

<Evaluation method>
The above sample was placed on a flat illuminator (HF-SL-A312LC manufactured by Dentsu Sangyo Co., Ltd., illuminance: 26,000 Lux, brightness: 10,000 cd), and a two-dimensional color luminance meter (manufactured by Konica Minolta Co., Ltd., CA-2000) was placed. ), And converted into a luminance distribution image by analysis software (manufactured by Konica Minolta, CA-S20w). The brightness distribution image of the obtained sample was evaluated based on FIG. 4 and the evaluation criteria shown below.
⊚: The brightness distribution is almost uniform.
◯: There is some distortion in the brightness distribution on all four sides.
Δ: There is a clear distortion in the brightness distribution on all four sides.
X: There is severe distortion in the brightness distribution on all four sides.

[Test Example 5] (Adhesive strength measurement-Reworkability evaluation)
A 25 mm wide and 100 mm long sample was cut out from the optical films with an adhesive layer obtained in Examples, Comparative Examples and Reference Examples, the release sheet was peeled off, and the non-alkali glass was passed through the exposed adhesive layer (Corning Inc.). After sticking to Eagle XG), the mixture was pressurized at 0.5 MPa and 50 ° C. for 20 minutes in an autoclave manufactured by Kurihara Seisakusho. Then, after leaving it to stand for 24 hours under the conditions of 23 ° C. and 50% RH, the adhesive strength (pasting) is performed under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180 degrees using a tensile tester (Tencilon manufactured by Orientec). Adhesive strength after 1 day; N / 25 mm) was measured. Conditions other than those described here were measured in accordance with JIS Z 0237: 2009. The results are shown in Table 2.

Further, after leaving it for 14 days under the conditions of 23 ° C. and 50% RH, the adhesive strength (adhesive strength 14 days after application; N / 25 mm) was measured in the same manner as described above. Separately, after leaving it for 2 days under the conditions of 50 ° C. and 50% RH, the adhesive strength (adhesive strength after 2 days at 50 ° C.; N / 25 mm) was measured in the same manner as described above. The results are shown in Table 2.

Based on the adhesive strength 14 days after the application, the reworkability was evaluated according to the following criteria. The results are shown in Table 2.
⊚: Adhesive strength 14 days after application is 8.8N / 25mm or less ○: Adhesive strength 14 days after application is more than 8.8N / 25mm and less than 10N / 25mm Δ: Adhesive force 14 days after application is 10N / 25mm or more, 20N Less than / 25mm ×: Adhesive strength 14 days after application is 20N / 25mm or more

[Test Example 6] (Measurement of surface resistivity of adhesive layer)
The optical films with an adhesive layer obtained in Examples, Comparative Examples and Reference Examples were cut into a size of 50 mm × 50 mm, and the obtained samples were left at a temperature of 23 ° C. and a humidity of 50% RH for 24 hours. .. After that, the release sheet was peeled off, and the surface resistivity (Ω / sq) of the exposed adhesive layer surface was (Ω / sq) according to JIS K6911 using a resistivity meter (HIRESTA UP MCP-HT450 type manufactured by Mitsubishi Chemical Analytech Co., Ltd.). ) Was measured. The results are shown in Table 2.

As can be seen from Table 2, the optical film with an adhesive layer obtained in the examples was excellent in durability, less likely to warp even at high temperatures, less likely to cause heat unevenness, and further excellent in reworkability. Further, the optical film with the pressure-sensitive adhesive layer obtained in the examples had a low surface resistivity of the pressure-sensitive adhesive layer and had a small adverse effect on the liquid crystal cell and the like. On the other hand, as shown in Reference Example 1, it can be seen that if the conventional polarizing plate is used, there is no problem in durability, heat unevenness and warpage suppression even if the same adhesive as in Comparative Example 1 is used. ..

The optical film with an adhesive layer according to the present invention is suitable for bonding a thinned polarizing plate or a composite polarizing plate to a liquid crystal cell.

10A, 10B ... Optical film with adhesive layer 1 ... Adhesive layer 2A ... Polarizing plate 2B ... Composite polarizing plate 21 ... Polarizer 22 ... First protective layer 23 ... Second protective layer 24 ... First retardation plate 241 ... First acrylic resin layer 242 ... Phase difference developing layer 243 ... Second acrylic resin layer 25 ... Second retardation plate 26 ... Second pressure-sensitive adhesive layer 27 ... Protective layer

Claims (10)

Optical film and
An optical film with an adhesive layer having an adhesive layer laminated on at least one side of the optical film.
The surface of the optical film in contact with the pressure-sensitive adhesive layer is made of an acrylic resin.
The pressure-sensitive adhesive layer
A (meth) acrylic acid ester copolymer (A) containing an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2), and an oxyalkylene group-containing monomer (a3) as a monomer unit constituting the polymer. When,
It comprises a pressure-sensitive adhesive obtained from a pressure-sensitive adhesive composition containing a cross-linking agent (B).
The (meth) acrylic acid ester copolymer (A) contains the aromatic ring-containing monomer (a2) in an amount of 12% by mass or more and 30% by mass or less as a monomer unit constituting the polymer, and is a carboxyl group-containing monomer. An optical film with an adhesive layer, which is characterized by not containing. The optical film with an adhesive layer according to claim 1, wherein the adhesive composition further contains an antistatic agent (C). The optical film with an adhesive layer according to claim 1 or 2, wherein the outermost surface layer of the optical film in contact with the pressure-sensitive adhesive layer is an acrylic resin layer formed through extrusion molding. The optical film with an adhesive layer according to claim 3, wherein the optical film includes at least a retardation plate having the acrylic resin layer and a retardation expression layer. The optical film with an adhesive layer according to claim 4, wherein the retardation expression layer is made of a styrene resin. The fourth or fifth aspect of the present invention, wherein the retardation plate has a second acrylic resin layer on a surface side of the retardation expression layer opposite to the surface of the acrylic resin layer side. Optical film with adhesive layer. The aspect according to any one of claims 4 to 6, wherein a second retardation plate is further laminated on the surface side of the retardation plate opposite to the surface on the pressure-sensitive adhesive layer side. Optical film with adhesive layer. The optical film with an adhesive layer according to claim 7, wherein the second retardation plate is made of a cycloolefin resin. The optical with an adhesive layer according to claim 7 or 8, wherein a polarizing plate is further laminated on the surface side of the second retardation plate opposite to the surface on the retardation plate side. the film. The (meth) acrylic acid ester copolymer (A)
A hydroxyl group-containing monomer (a4) is further contained as a monomer unit constituting the polymer.
The optical film with an adhesive layer according to any one of claims 1 to 9, wherein the hydroxyl value is 5 mgKOH / g or more and 20 mgKOH / g or less.

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