KR102469384B1 - Optical film with adhesive layer - Google Patents

Abstract

(Problem) To provide an optical film with a pressure-sensitive adhesive layer that is excellent in durability and does not easily generate heat unevenness even when a thin optical film is used.
(Solution) An optical film with an adhesive layer (10A) provided with an optical film and an adhesive layer (1) laminated on at least one surface of the optical film, wherein the surface in contact with the adhesive layer (1) in the optical film is an acrylic resin. and (meth)acrylic acid ester copolymer (A) in which the pressure-sensitive adhesive layer (1) contains an alicyclic structure-containing monomer (a1) and an aromatic ring-containing monomer (a2) as monomer units constituting the polymer, and a crosslinking agent 10 A of optical films with an adhesive layer which consist of the adhesive obtained from the adhesive composition which contains (B) and whose content of a low molecular-weight component is 5 mass % or less.

Description

Optical film with adhesive layer {OPTICAL FILM WITH ADHESIVE LAYER}

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

BACKGROUND OF THE INVENTION [0002] In recent years, as display panels of various electronic devices, touch panels that serve as both display devices and input means have been widely used. Types of touch panels mainly include resistive, capacitive, optical and ultrasonic types. Resistive types include analog resistive and matrix resistive types, and capacitance types include surface and projection types.

BACKGROUND OF THE INVENTION As for touch panels in mobile electronic devices such as smart phones and tablet terminals that have recently attracted attention, projection-type capacitive touch panels are often used. As a projection type capacitive touch panel in such a mobile electronic device, for example, in order from the bottom, a liquid crystal display device (LCD), an adhesive layer, a transparent conductive film (tin-doped indium oxide: ITO), a glass substrate, It has been proposed to laminate a transparent conductive film (ITO) and a protective plate such as tempered glass.

As an optical component constituting the liquid crystal display device, a liquid crystal cell is generally used. A liquid crystal cell is generally arranged so that the orientation layer of two transparent electrode substrates on which the orientation layer is formed is placed inside so as to be spaced at a predetermined interval by a spacer, and the periphery thereof is sealed, and the liquid crystal material is placed between the two transparent electrode substrates. will be interfering with Usually, a polarizing plate or a composite polarizing plate having a retardation plate is bonded to the outside of two transparent electrode substrates in a liquid crystal cell through an adhesive, respectively.

As an optical adhesive, what was disclosed in patent document 1 is known, for example. This pressure-sensitive adhesive is a (meth)acrylic polymer containing, as a monomer unit, 0.2 to 20 parts by mass of a carboxyl group-containing monomer as a copolymerization component based on 100 parts by mass of an alkyl (meth)acrylate having an alkyl group having 4 to 14 carbon atoms, and 0.02-2 mass parts of peroxides and 0.005-5 mass parts of epoxy-type crosslinking agents are contained as a crosslinking agent with respect to 100 mass parts of (meth)acrylic polymers.

Patent Document 1: Japanese Unexamined Patent Publication No. 2009-242786

Here, in accordance with the recent request for thinning of mobile electronic devices, thinning of optical films such as polarizing plates is also required. However, a thin film polarizing plate has a high shrinkage rate due to heat or the like, and in conventional pressure-sensitive adhesives such as Patent Document 1, lifting or peeling occurs under high temperature conditions or under moist heat conditions. Furthermore, a problem has been pointed out that light leakage (so-called heat non-uniformity) occurs due to the displacement of the optical axis of the optical film due to the stress at the time of thermal contraction of the optical film.

In addition, when thinning the optical film is prioritized, adhesion to the adhesive deteriorates, and in conventional adhesives such as Patent Document 1, adhesion at the interface between the optical film and the adhesive tends to become insufficient and durability further deteriorates. .

The present invention has been made in view of such a real situation, and an object of the present invention is to provide an optical film with an adhesive layer that is excellent in durability and does not easily generate heat unevenness even when a thinned optical film is used.

In order to achieve the above object, first, the present invention is an optical film with a pressure-sensitive adhesive layer provided with an optical film and a pressure-sensitive adhesive layer laminated on at least one side of the optical film, wherein the surface of the optical film is in contact with the pressure-sensitive adhesive layer. It is composed of silver and an acrylic resin, and the pressure-sensitive adhesive layer includes a (meth)acrylic acid ester copolymer (A) containing an alicyclic structure-containing monomer (a1) and an aromatic ring-containing monomer (a2) as monomer units constituting the polymer. and a crosslinking agent (B), and an optical film with an adhesive layer characterized by comprising an adhesive obtained from an adhesive composition containing a low molecular weight component of 5% by mass or less (Invention 1).

According to the above invention (invention 1), even when the optical film used is thinner than conventional products, durability is excellent when applied to a display panel, and lifting or peeling is suppressed even under high temperature conditions or moist heat conditions. . Moreover, the display panel using the said optical film with an adhesive layer does not generate heat nonuniformity easily.

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

In the above invention (invention 2), it is preferable that the optical film is provided with a retardation plate having at least the acrylic resin layer and a retardation developing layer (invention 3).

In the above invention (invention 3), it is preferable that the phase difference expression layer is made of a styrenic resin (invention 4).

In the above inventions (Inventions 3 and 4), it is preferable that the retardation plate has a second acrylic resin layer on the surface side opposite to the surface on the side of the acrylic resin layer in the phase difference developing layer (Invention 5). ).

In the above inventions (Inventions 3 to 5), it is preferable that a second retardation plate is further laminated on the side opposite to the surface of the retardation plate on the side of the pressure-sensitive adhesive layer (Invention 6).

In the above invention (Invention 6), it is preferable that the second retardation plate is made of a cycloolefin-based resin (Invention 7).

In the above inventions (Inventions 6 and 7), it is preferable that a polarizing plate is further laminated on the side of the second retardation film opposite to the surface on the side of the retardation film (Invention 8).

In the above invention (Inventions 1 to 8), the (meth)acrylic acid ester copolymer (A) further contains a hydroxyl group-containing monomer (a3) as a monomer unit constituting the polymer, and has a hydroxyl value of 5 to 20 mgKOH /g is preferred (Invention 9).

In the above inventions (Inventions 1 to 9), it is preferable that the crosslinking agent (B) is an isocyanate-based crosslinking agent (Invention 10).

In the above inventions (Inventions 1 to 10), it is preferable that the adhesive composition further contains a silane coupling agent (C) (Invention 11).

In the above inventions (Inventions 1 to 11), it is preferable that the adhesive composition further contains an antistatic agent (D) (Invention 12).

In the above invention (Invention 12), it is preferable that the antistatic agent (D) is an ionic compound that is solid at room temperature and composed of a nitrogen-containing heterocyclic cation and a halogenated phosphate anion (Invention 13).

ADVANTAGE OF THE INVENTION According to the optical film with an adhesive layer concerning this invention, even when an optical film is thinned, it is excellent in durability, and a display panel is hard to generate heat nonuniformity.

1 is a cross-sectional view of an optical film with a pressure-sensitive adhesive layer according to an embodiment of the present invention.
Fig. 2 is a cross-sectional view of an optical film with a pressure-sensitive adhesive layer according to another embodiment of the present invention.
3 is a cross-sectional view showing a configuration example of a retardation plate.
4 is a diagram (color) showing evaluation criteria for a heat resistance nonuniformity test (visual observation) in an optical film with an adhesive layer.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described.

An optical film with a pressure-sensitive adhesive layer according to the present embodiment includes an optical film and a pressure-sensitive adhesive layer laminated on at least one surface of the optical film. The surface in contact with the pressure-sensitive adhesive layer in the optical film is composed of an acrylic resin, and the pressure-sensitive adhesive layer contains an alicyclic structure-containing monomer (a1) and an aromatic ring-containing monomer (a2) as monomer units constituting the polymer (method ) An adhesive obtained from an adhesive composition containing an acrylic acid ester copolymer (A) and a crosslinking agent (B) and having a low molecular weight component content of 5% by mass or less (hereinafter sometimes referred to as “adhesive composition (P)”) It is done. In addition, in this specification, (meth)acrylic acid ester means both acrylic acid ester and methacrylic acid ester. The same goes for other similar terms.

Even when the optical film with the pressure-sensitive adhesive layer is thinned compared to conventional products, when applied to a display panel, the optical film with an adhesive layer can be used under durability conditions (under high-temperature conditions, under moist heat conditions, or as exemplified in test examples described later). In addition to heat shock, the occurrence of lifting or peeling is suppressed even in a high temperature environment or a moist heat environment during actual use (the same applies below unless otherwise specified). Moreover, the display panel using the said optical film with an adhesive layer does not generate heat nonuniformity easily.

Here, the optical film often consists of a function expression layer that expresses optical performance such as polarization performance and retardation performance, and a protective layer (for shape retention) for protecting the function expression layer to maintain shape stability. The inventors of the present invention found that, by using an acrylic resin for the protective layer, the optical performance of the function expression layer was not lowered and thinning was possible. However, in the conventional optical film with an adhesive layer, when the protective layer is thinned using an acrylic resin, the shape retention under durability conditions becomes insufficient, and the adhesiveness with the pressure-sensitive adhesive layer becomes insufficient, and as a result, the optical film The used optical film with a pressure-sensitive adhesive layer was not satisfactory in both durability and heat resistance nonuniformity. In contrast, in the optical film with a pressure-sensitive adhesive layer according to the present embodiment, the residual stress of the pressure-sensitive adhesive layer due to shrinkage of the optical film under durability conditions is eliminated by increasing the stress relaxation property of the pressure-sensitive adhesive layer with the composition described above.

Regarding the lack of adhesion between the protective layer made of acrylic resin and the pressure-sensitive adhesive layer, the present inventors, as a result of intensively observing the interface between the protective layer and the pressure-sensitive adhesive layer after the durability test, found that certain components were sucked out from the pressure-sensitive adhesive layer toward the protective layer side. I found out that there are visible flaws. From this discovered phenomenon, under durable conditions, the low molecular weight components in the pressure-sensitive adhesive layer are attracted to the protective layer side, and the low molecular weight components exist at the interface between the protective layer and the pressure-sensitive adhesive layer. , it was inferred that the adhesion at the interface was lowered. Based on this reasoning, the glass transition temperature (Tg) of the main polymer of the pressure-sensitive adhesive layer is raised by the above-described composition, and the content of the low-molecular-weight component is suppressed to 5% by mass or less, thereby removing the optical fiber from the pressure-sensitive adhesive layer under durability conditions. While making it difficult for the low-molecular-weight component to be sucked into the film (the part composed of the acrylic resin), even if it is sucked, it is very small, so it is intended to prevent it from performing a lubricating oil function.

[Adhesive layer]

(1) (meth)acrylic acid ester copolymer (A)

The (meth)acrylic acid ester copolymer (A) in the present embodiment contains an alicyclic structure-containing monomer (a1) and an aromatic ring-containing monomer (a2) as monomer units constituting the polymer. By containing these alicyclic structure-containing monomers (a1) and aromatic ring-containing monomers (a2), the obtained adhesive can have both appropriate cohesive force and stress relaxation properties, and since the adhesiveness to acrylic resin is increased, display panels When used for, it can exhibit excellent durability, warpage inhibition and heat resistance nonuniformity.

The (meth)acrylic acid ester copolymer (A) contains a hydroxyl group-containing monomer (a3) in addition to the above alicyclic structure-containing monomer (a1) and aromatic ring-containing monomer (a2) as monomer units constituting the polymer. is preferred, and it is particularly preferred that the alkyl group contains a (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms. Moreover, you may contain other monomers as desired.

Here, the hydroxyl value of the (meth)acrylic acid ester copolymer (A) is preferably 5 mgKOH/g or more, from the viewpoint of ensuring excellent durability of the adhesive obtained by securing a crosslinking point and maintaining a high cohesive force, and 8 mgKOH /g or more is particularly preferred, and 10 mgKOH/g or more is more preferred. On the other hand, the hydroxyl value is preferably 30 mgKOH / g or less from the viewpoint of preventing an excessive increase in crosslinking points and providing excellent durability and heat resistance nonuniformity of the adhesive obtained, and from the viewpoint of suppression of warpage under high temperature in a display panel In addition, it is particularly preferably 20 mgKOH/g or less, and more preferably 16 mgKOH/g or less.

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 more preferably 1 mgKOH/g or less. If the acid value of the (meth)acrylic acid ester copolymer (A) is 5 mgKOH/g or less, the object to which the pressure-sensitive adhesive is applied is a problem caused by acid, for example, a transparent conductive film such as tin-doped indium oxide (ITO) or the like. Even in the case of a metal film or the like, these problems due to acid can be suppressed. In particular, when the object to be pasted is a transparent conductive film, it can suppress corroding the transparent conductive film or changing the resistance value of the transparent conductive film. Moreover, since the lower limit of the acid value of the (meth)acrylic acid ester copolymer (A) is so preferable that it is small, it is particularly preferable that it is 0 mgKOH/g.

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

The (meth)acrylic acid ester copolymer (A) can express desirable adhesiveness by containing, as a monomer unit constituting the polymer, a (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in an alkyl group. Examples of (meth)acrylic acid alkyl esters having 1 to 20 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, and (meth)acrylate. n-pentyl acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, (meth)acrylic acid Myristyl, palmityl (meth)acrylate, stearyl (meth)acrylate, etc. are mentioned. Among them, from the viewpoint of further improving the adhesiveness, (meth)acrylic acid esters having 1 to 8 carbon atoms in the alkyl group are preferred, and n-butyl (meth)acrylate or 2-ethylhexyl (meth)acrylate is particularly preferred. In addition, these may be used independently and may be used in combination of 2 or more type.

The (meth)acrylic acid ester copolymer (A) preferably contains, as a monomer unit constituting the polymer, 40 to 97.5% by mass of (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group, particularly 55 to 97.5% by mass. It is preferable to contain 94 mass %, and also it is preferable to contain 65-83 mass %. When 40 mass % or more of (meth)acrylic-acid alkylester is contained, favorable adhesiveness can be provided to a (meth)acrylic-acid ester copolymer (A). Moreover, by setting the (meth)acrylic acid alkyl ester to 97.5% 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 of the alicyclic structure in the alicyclic structure-containing monomer (a1) may have a saturated structure or may partially have an unsaturated bond. In addition, the alicyclic structure may be a monocyclic alicyclic structure or a polycyclic alicyclic structure such as two or three rings. The distance between the (meth)acrylic acid ester copolymers (A) obtained is appropriate, and the viewpoint of imparting stress relaxation properties to the pressure-sensitive adhesive and the glass transition temperature (Tg) of the obtained copolymer (A) are raised. It is preferable that the said alicyclic structure is a polycyclic alicyclic structure (polycyclic structure) from a viewpoint of preventing a low molecular weight component from migrating to the acrylic resin side and impairing adhesiveness. In consideration of the compatibility of the (meth)acrylic acid ester copolymer (A) and other components, the polycyclic structure is particularly preferably a two- or four-ring structure. In addition, as in the above, from the viewpoint of imparting stress relaxation properties, the number of carbon atoms in the alicyclic structure (meaning all the number of carbon atoms in the portion forming the ring, and referring to the total number of carbon atoms when a plurality of rings exist independently) , 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 is preferably 15 or less, particularly preferably 10 or less, from the viewpoint of compatibility as described above.

Examples of the alicyclic structure include cyclohexyl skeleton, dicyclopentadiene skeleton, adamantane skeleton, isobornyl skeleton, cycloalkane skeleton (cycloheptane skeleton, cyclooctane skeleton, cyclononane skeleton, cyclodecane skeleton, cycloundecane skeleton, cyclododecane skeleton, etc.), cycloalkene skeleton (cycloheptene skeleton, cyclooctene skeleton, etc.), norbornene skeleton, norbornadiene skeleton, cubane skeleton, basketane skeleton, housein skeleton, Examples include those containing spiro skeletons and the like, and among them, dicyclopentadiene skeletons (carbon atoms in an alicyclic structure: 10), adamantane skeletons (carbon atoms in an alicyclic structure: 10), or It is preferable to include an isobornyl skeleton (carbon number of the alicyclic structure: 7), and it is particularly preferable to include an isobornyl skeleton.

As the alicyclic structure-containing monomer (a1), a (meth)acrylic acid ester monomer containing the above skeleton is preferable. Specifically, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and (meth)acrylic acid adamantyl, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and the like, among which, (meth) Dicyclopentanyl acrylate, adamantyl (meth)acrylate or isobornyl (meth)acrylate is 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) contains an alicyclic structure-containing monomer (a1) from 1 to 20 as a monomer unit constituting the polymer, from the viewpoint of exhibiting excellent durability, warpage suppression property, and heat resistance nonuniformity of the resulting adhesive. It is preferable to contain mass %. In addition to the above viewpoints, from the viewpoint of exhibiting excellent reworkability of the pressure-sensitive adhesive obtained, the alicyclic structure-containing monomer (a1) is more preferably contained in an amount of 2 to 15% by mass, and preferably contained in an amount of 3 to 9% by mass. particularly preferred.

As the aromatic ring-containing monomer (a2), a (meth)acrylic acid ester having an aromatic ring is preferable. As an aromatic ring, a benzene ring, a naphthalene ring, an anthracene ring, a biphenyl ring, a fluorene ring, etc. are mentioned, Among them, 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, phenoxyethyl (meth)acrylate, ( Meth) phenoxybutyl acrylate, ethoxylated o-phenylphenol acrylate, phenoxydiethylene glycol (meth)acrylate, ethylene oxide modified cresol (meth)acrylate, ethylene oxide (EO) modified nonylphenol (meth)acrylate, etc. are mentioned, and among them, 2-phenylethyl (meth)acrylate is preferable from the point of improving cohesive force. These may be used independently and may be used in combination of 2 or more type.

The (meth)acrylic acid ester copolymer (A) preferably contains 1 to 30% by mass of an aromatic ring-containing monomer (a2) as a monomer unit constituting the polymer, particularly preferably 3 to 25% by mass Furthermore, it is preferable to contain 12-22 mass %. When the content of the aromatic ring-containing monomer (a2) is within the above range, the resulting pressure-sensitive adhesive can exhibit excellent durability, warpage suppression properties, and nonuniformity in heat resistance.

The (meth)acrylic acid ester copolymer (A) preferably contains a hydroxyl group-containing monomer (a3) as a monomer unit constituting the polymer. The hydroxyl group shows good reactivity with the crosslinking agent (B), and the (meth)acrylic acid ester copolymer (A) is crosslinked by the crosslinking agent (B) by these reactions. Due to this crosslinked structure, the resulting pressure-sensitive adhesive becomes highly durable.

Examples of the hydroxyl group-containing monomer (a3) include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 2-hydroxy (meth)acrylate. (meth)acrylic acid hydroxyalkyl esters such as butyl, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate is preferred, and 2-hydroxyethyl (meth)acrylate is particularly preferred. These may be used independently and may be used in combination of 2 or more type.

The (meth)acrylic acid ester copolymer (A) preferably contains 0.5 to 10 mass% of a hydroxyl group-containing monomer (a3) as a monomer unit constituting the polymer, particularly preferably 1 to 5 mass% Furthermore, it is preferable to contain 2-4 mass %. When the content of the hydroxyl group-containing monomer (a3) is within the above range, the hydroxyl value of the (meth)acrylic acid ester copolymer (A) tends to fall within the above range, and excellent durability and nonuniformity in heat resistance can be effectively exhibited. Moreover, especially when content of a hydroxyl-containing monomer (a3) is 4 mass % or less, in the display panel obtained, it becomes excellent in curvature suppression property under high temperature.

The (meth)acrylic acid ester copolymer (A) preferably does not contain a carboxyl group-containing monomer as a monomer unit constituting the polymer also in order to set the acid value within the above-mentioned range, and even if it does, the content is 0.5% by mass or less. It is preferable to contain it, and it is especially preferable to contain it with a content of 0.1 mass % or less.

The (meth)acrylic acid ester copolymer (A) may contain other monomers other than the above-mentioned monomers as monomer units constituting the polymer. As the other monomer, a monomer that does not contain a functional group reactive with the crosslinking agent (B) is preferable in order not to interfere with the reaction between the hydroxyl group of the hydroxyl group-containing monomer (a3) and the crosslinking agent (B).

Examples of such other monomers include (meth)acrylic acid alkoxyalkyl esters such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate, non-crosslinkable acrylamides such as acrylamide and methacrylamide, ( (meth)acrylic acid esters having non-crosslinkable tertiary amino groups such as N,N-dimethylaminoethyl meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate; and vinyl acetate. These may be used independently and may be used in combination of 2 or more type.

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 to 3 million, particularly preferably 1.5 million to 2.5 million, and more preferably 1.6 million to 1.9 million. When the weight average molecular weight of the (meth)acrylic acid ester copolymer (A) is 1,300,000 or more, the durability of the resulting adhesive can be ensured satisfactorily. Moreover, if the weight average molecular weight of a (meth)acrylic acid ester copolymer (A) is 3 million or less, the stress relaxation property of the adhesive obtained can be ensured satisfactorily, and warpage suppression property and heat-resistant nonuniformity can be exhibited effectively.

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

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

(2) crosslinking agent (B)

The crosslinking agent (B) should just react with the functional group of the (meth)acrylic acid ester copolymer (A), and examples thereof include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, amine-based crosslinking agents, melamine-based crosslinking agents, aziridine-based crosslinking agents, and hydrazine. crosslinking agents, aldehyde crosslinking agents, oxazoline crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents, and ammonium salt crosslinking agents.

When the (meth)acrylic acid ester copolymer (A) contains a hydroxyl group-containing monomer (a3) as a monomer unit constituting the polymer, an isocyanate-based crosslinking agent having excellent reactivity with hydroxyl groups derived from the hydroxyl group-containing monomer (a3) It is preferable to use In addition, a crosslinking agent (B) can be used individually by 1 type or in combination of 2 or more types.

The isocyanate-based crosslinking 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 diisocyanate, and hydrogenated diphenylmethane. In addition to alicyclic polyisocyanates such as diisocyanates, their biurets, isocyanurates, and further, reactants with low molecular weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil adducts (above generically referred to as “denatured substances” in some cases); and the like. Among these, from the viewpoint of the durability of the pressure-sensitive adhesive obtained, 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 preferable, and a carbon number of 1 A polyisocyanate having an isocyanate group bonded via an alkylene chain of to 4 or a modified product thereof is particularly preferred. Specifically, xylylene diisocyanate or a modified product thereof is more preferable, and trimethylolpropane-modified xylylene diisocyanate is most preferable. The said isocyanate type crosslinking agent can be used individually by 1 type or in combination of 2 or more types.

The content of the crosslinking agent (B) in the adhesive composition (P) is preferably from 0.01 to 10 parts by mass, particularly preferably from 0.05 to 5 parts by mass, based on 100 parts by mass of the (meth)acrylic acid ester copolymer (A). and, by extension, it is preferably 0.1 to 0.4 parts by mass. When the content of the crosslinking agent (B) is within the above range, the resultant adhesive exhibits good cohesive force and stress relaxation properties, and has more excellent durability and nonuniformity in heat resistance. Moreover, especially when content of a crosslinking agent (B) is 0.4 mass % or less, in the display panel obtained, it becomes excellent in the curvature suppression property under high temperature.

(3) Silane coupling agent (C)

The adhesive composition (P) preferably contains a silane coupling agent (C) in addition to the (meth)acrylic acid ester copolymer (A) and the crosslinking agent (B), and from the viewpoint of imparting excellent durability to the resulting adhesive, particularly It is preferable to contain an epoxy group-containing silane coupling agent (C1) and/or a mercapto group-containing silane coupling agent (C2), and furthermore, of the epoxy group-containing silane coupling agent (C1) and the mercapto group-containing silane coupling agent (C2) It is preferable to contain both.

The epoxy group-containing silane coupling agent (C1) is an organosilicon compound having at least one epoxy group (organic group containing an epoxy group) and at least one alkoxysilyl group in the molecule, and has good compatibility with the pressure-sensitive adhesive component and has light transmission properties. , for example substantially transparent.

Specific examples of the epoxy group-containing silane coupling agent (C1) include 3-glycidoxypropyltrialkoxysilanes such as 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropyltrialkoxysilane. 3-glycidoxypropylalkyldialkoxysilanes such as cidoxypropylmethyldiethoxysilane and 3-glycidoxypropylmethyldimethoxysilane, methyltri(glycidyl)silane, 2-(3,4-epoxycyclohexyl) ) 2-(3,4-epoxycyclohexyl)ethyltrialkoxysilanes such as ethyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)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 preferred, and 3-glycidoxypropyltrimethoxysilane is particularly preferred. 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 (C2) 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. Compatibility with pressure-sensitive adhesive components It is preferable, and it is preferable to have light transmission, for example, to be substantially transparent.

Specific examples of the mercapto group-containing silane coupling agent (C2) include mercapto groups such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane. containing low molecular weight silane coupling agent; Mercapto group-containing silane compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane, methyltriethoxysilane, and ethyltriethoxysilane , mercapto group-containing oligomer type silane coupling agents such as cocondensates of alkyl group-containing silane compounds such as methyltrimethoxysilane and ethyltrimethoxysilane. Among them, from the viewpoint of achieving both durability and reworkability, a mercapto group-containing oligomer type silane coupling agent is preferable, and a cocondensate of a mercapto group-containing silane compound and an alkyl group-containing silane compound is particularly preferable, and furthermore, 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 (C), in addition to the above epoxy group-containing silane coupling agent (C1) and mercapto group-containing silane coupling agent (C2), if necessary, for example, an acryloyl-based silane coupling agent, a hydroxyl-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 (C) in the adhesive composition (P) is preferably from 0.01 to 5 parts by mass, particularly from 0.1 to 2 parts by mass, based on 100 parts by mass of the (meth)acrylic acid ester copolymer (A). It is preferable, and it is preferable that it is 0.2-1 mass part by extension.

The content of the epoxy group-containing silane coupling agent (C1) in the adhesive composition (P) is preferably 0.005 to 2.5 parts by mass, particularly 0.05 to 2.5 parts by mass, based on 100 parts by mass of the (meth)acrylic acid ester copolymer (A). It is preferable that it is 1 mass part, and also it is preferable that it is 0.1-0.5 mass part. On the other hand, the content of the mercapto group-containing silane coupling agent (C2) in the adhesive composition (P) is preferably from 0.005 to 2.5 parts by mass, particularly based on 100 parts by mass of the (meth)acrylic acid ester copolymer (A). It is preferable that it is 0.05-1 mass part, and also it is preferable that it is 0.1-0.5 mass part.

(4) antistatic agent (D)

It is preferable that the adhesive composition (P) further contains an antistatic agent (D). Since the release sheet laminated on the pressure-sensitive adhesive layer or the optical member such as a polarizing plate or composite polarizing plate is usually made of a plastic material, electrical insulation is high and static electricity is likely to be generated when the release sheet is peeled off. If a polarizing plate or a composite polarizing plate or the like is bonded to a liquid crystal cell in a state in which static electricity generated in this way remains, there is a risk that the alignment of liquid crystal molecules may be disturbed, and the presence of static electricity may attract dust and dirt. cause problems Then, when the adhesive composition (P) contains the antistatic agent (D), the adhesive (adhesive layer) obtained exhibits antistatic properties, and the above problems can be eliminated.

As an antistatic agent (D), what is necessary is just to be able to provide antistatic property to the adhesive obtained, and although an ionic compound and a nonionic compound etc. are mentioned, for example, an ionic compound is especially preferable. The ionic compound may be a liquid or a solid at room temperature, but is preferably a solid at room temperature from the viewpoint of easy to exhibit stable antistatic properties even when exposed to durability conditions. Here, the ionic compound in this specification refers to a compound in which cations and anions are mainly bound by electrostatic attraction.

As the ionic compound, nitrogen-containing onium salts, sulfur-containing onium salts, phosphorus-containing onium salts, alkali metal salts and alkaline earth metal salts are preferable, and nitrogen-containing onium salts are particularly preferable from the viewpoint of excellent durability of the resulting adhesive. The nitrogen-containing onium salt is preferably an ionic compound composed of a nitrogen-containing heterocyclic cation and its counter anion, and is particularly preferably an ionic compound composed of a nitrogen-containing heterocyclic cation and a halogenated phosphoric acid anion. Furthermore, it is preferable that it is an ionic compound composed of a nitrogen-containing heterocyclic cation and a halogenated phosphoric acid anion as a solid at room temperature. According to the ionic compound composed of a nitrogen-containing heterocyclic cation and a halogenated phosphoric acid anion as a solid at room temperature, both antistatic properties and durability become possible.

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 halogen of the halogenated phosphoric acid anion, fluorine, chlorine, bromine and the like are preferable, and fluorine is particularly preferable.

Specific examples of the antistatic agent (C) include N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methylpyridinium hexafluorophosphate, N-octylpyridinium hexafluorophosphate, 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, 1-butylpyridinium hexafluorophosphate Fluorophosphate, 1-butyl-3-methylimidazolium hexafluorophosphate, etc. are mentioned. Among these, from the viewpoint of compatibility with (meth)acrylic acid ester copolymer (A), N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methylpyridinium hexafluorophosphate, N-octyl -4-methylpyridinium hexafluorophosphate and 1-butylpyridinium hexafluorophosphate are preferred. The above antistatic agent (C) may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the antistatic agent (D) in the adhesive composition (P) is preferably 0.1 to 15 parts by mass, particularly preferably 0.5 to 10 parts by mass, based on 100 parts by mass of the (meth)acrylic acid ester copolymer (A). Furthermore, it is preferable that it is 1-5 mass parts. When the content of the antistatic agent (D) is within the above range, antistatic properties can be effectively exhibited, and deterioration in physical properties such as optical properties and durability can be prevented.

(5) low molecular weight components

The low molecular weight component in this specification means that it does not correspond to any of the said components (B)-(D), and molecular weight (weight average molecular weight in the case of a polymer) is 10,000 or less. Examples of such low molecular weight components include acrylic polymers, styrenic polymers, urethane polymers, and silicones having a weight average molecular weight of 10,000 or less; Hydrocarbons having a molecular weight of 1000 or less, for example, stilbene (cisstilbene, transstilbene), benzyl benzoate, fluorene, diphenylsulfide and the like, but are not limited thereto.

The content of the low molecular weight component in the adhesive composition (P) is 5% by mass or less. When the content of the low-molecular-weight component is 5% by mass or less, the probability that the low-molecular-weight component in the pressure-sensitive adhesive layer will be absorbed to the optical film side (the part composed of acrylic resin) decreases, and even if it is sucked out, the amount Since it is small, it is possible to suppress the function of the low molecular weight component as a lubricating oil. As a result, the adhesiveness of the pressure-sensitive adhesive layer to the optical film increases, and excellent durability can be exhibited when used for a display panel.

From the above viewpoint, the content of the low molecular weight component in the adhesive composition (P) is preferably 3% by mass or less, particularly preferably 2% by mass or less, and more preferably 1.5% by mass or less. In addition, it is preferable that the lower limit of the content of the low molecular weight component in the adhesive composition (P) is 0% by mass.

In addition, in this embodiment, by using the (meth)acrylic acid ester copolymer (A) of the above-mentioned composition as the main agent of the adhesive composition (P), the glass transition temperature (Tg) of the (meth)acrylic acid ester copolymer (A) ) rises, and accordingly, the attraction itself of the low molecular weight component from the pressure-sensitive adhesive layer to the optical film under durability conditions is suppressed.

(6) Various additives

In the adhesive composition (P), as desired, various additives commonly used for acrylic adhesives, such as dispersants (eg, alkylene glycol dialkyl ethers), tackifiers, antioxidants, ultraviolet absorbers, light stabilizers , softeners, fillers, refractive index adjusters and the like can be added. In addition, although some of these additives correspond to the said low molecular weight component, even in that case, it is necessary that content of the low molecular weight component in adhesive composition (P) is 5 mass % or less. In addition, the adhesive composition (P) represents a mixture of various components remaining in the adhesive layer as it is or in a reacted state, and components removed in a drying step or the like, for example, a polymerization solvent or a dilution solvent described later , are not included in the adhesive composition (P).

(7) Method for producing adhesive composition

The adhesive composition (P) is prepared by preparing a (meth)acrylic acid ester copolymer (A), the obtained (meth)acrylic acid ester copolymer (A), a crosslinking agent (B), and optionally a silane coupling agent (C) , antistatic agent (D), additives, etc. can be manufactured by mixing.

The (meth)acrylic acid ester copolymer (A) can be produced by polymerizing a mixture of monomer units constituting the polymer by a conventional radical polymerization method. 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 as desired. As a polymerization solvent, ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone etc. are mentioned, for example, You may use 2 or more types together.

As a polymerization initiator, an azo type compound, an organic peroxide, etc. are mentioned, You may use 2 or more types together. Examples of the azo-based compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), and 1,1'-azobis(cyclohexane 1- carbonitrile), 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] etc. are mentioned.

As the organic peroxide, for example, benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropylperoxydicarbonate, di-n-propylperoxydicarbonate, di-(2-ethoxyethyl)peroxide cidicarbonate, t-butylperoxyneodecanoate, t-butylperoxypivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide and the like. .

Moreover, in the said polymerization process, the weight average molecular weight of the polymer obtained can be adjusted by mix|blending a chain transfer agent, such as 2-mercaptoethanol.

When the (meth)acrylic acid ester copolymer (A) is obtained, to a solution of the (meth)acrylic acid ester copolymer (A), a crosslinking agent (B), and optionally a silane coupling agent (C), an antistatic agent (D), An additive, a diluting solvent, etc. are added and thoroughly mixed to obtain a solvent-diluted adhesive composition (P) (coating solution).

Diluting solvents for diluting the adhesive composition (P) to form a coating solution include, for example, aliphatic hydrocarbons such as hexane, heptane, and cyclohexane, aromatic hydrocarbons such as toluene and xylene, and halogenated hydrocarbons such as methylene chloride and ethylene chloride. Hydrocarbons, alcohols such as methanol, ethanol, propanol, butanol and 1-methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone and cyclohexanone, ethyl acetate and butyl acetate Cellosolve solvents such as ester and ethyl cellosolve are used.

The concentration and viscosity of the coating solution prepared in this way may be within a range capable of being coated, and are not particularly limited, and can be appropriately selected according to the situation. For example, it is diluted so that the concentration of the adhesive composition (P) may become 10-40 mass %. In addition, when obtaining a coating solution, addition of a diluting solvent is not a necessary condition, and as long as the adhesive composition (P) has a coatingable viscosity or the like, it is not necessary to add a diluting solvent. In this case, the adhesive composition (P) becomes a coating solution in which the polymerization solvent of the (meth)acrylic acid ester copolymer (A) is used as a diluting solvent as it is.

(8) adhesive

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer in the present embodiment is obtained from the above-described pressure-sensitive adhesive composition (P), and is specifically formed by crosslinking the pressure-sensitive adhesive composition (P). Crosslinking of the adhesive composition (P) can be performed by heat treatment. Note that this heat treatment can also serve as a drying treatment for volatilizing the diluting solvent or the like of the adhesive composition (P).

In the case of heat treatment, the heating temperature is preferably 50 to 150°C, particularly preferably 70 to 120°C. Moreover, it is preferable that it is 30 second - 10 minutes, and, as for heating time, it is preferable that it is 50 second - 2 minutes especially. After the heat treatment, a curing period of about 1 to 2 weeks may be provided at normal temperature (for example, 23°C, 50% RH) as needed. When this curing period is required, after the curing period has elapsed, and when the curing period is unnecessary, after the heat treatment is completed, an adhesive layer having predetermined physical properties is formed.

By the heat treatment (and curing) described above, the (meth)acrylic acid ester copolymer (A) is crosslinked with the crosslinking agent (B) to form a three-dimensional mesh structure.

The degree of crosslinking of the pressure-sensitive adhesive, that is, the gel fraction, is preferably 40 to 90%, particularly preferably 60 to 85%, and more preferably 73 to 78%. When the gel fraction is 40% or more, the adhesive has more excellent durability. Moreover, when the gel fraction is 90% or less, the stress relaxation property of the pressure-sensitive adhesive becomes better, and the warpage suppression property and heat resistance nonuniformity become more excellent. In addition, the measuring method of the gel fraction of an adhesive is as showing in the test example mentioned later.

(9) physical properties of the pressure-sensitive adhesive layer

The thickness of the pressure-sensitive adhesive layer is preferably 5 to 100 μm, more preferably 10 to 60 μm, particularly preferably 10 to 50 μm, and still more preferably 15 to 30 μm.

It is preferable that it is 2 % or less, and, as for the haze value (value measured according to JIS K7136:2000) of an adhesive layer, it is especially preferable that it is 1 % or less. Transparency is very high as haze value is 2 % or less, and it becomes a thing suitable as an optical use.

[Optical Film]

The optical film in this embodiment may consist of a single layer or may consist of multiple layers. As the optical film, for example, 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 luminance enhancing film, a contrast enhancing film, a liquid crystal polymer film, a diffusion film, a transflective film, those A laminated body etc. are mentioned. Among them, the optical film containing the polarizer is preferable as the optical film of the optical film with a pressure-sensitive adhesive layer according to the present embodiment, from the viewpoint that the polarizer contracts easily, has a large dimensional change, and requires durability. In particular, a thin polarizing plate having a thin protective layer and a composite polarizing plate using the polarizing plate are easily contracted by heat or the like because the protective layer suppresses shrinkage of the polarizer. It is most suitable as an optical film of an optical film with an adhesive layer.

Here, the surface in contact with the pressure-sensitive adhesive layer in the optical film is constituted by an acrylic resin. By using an acrylic resin at the location of the optical film, the film thickness can be reduced without impairing the prescribed optical performance. When an optical film consists of a single layer, the said optical film consists of a single layer of acrylic resin. When the optical film consists of a plurality of layers, it is preferable that the outermost layer in contact with the pressure-sensitive adhesive layer consists of an acrylic resin layer formed through extrusion molding. These acrylic resins and conventionally known pressure-sensitive adhesive layers had low adhesion and low durability. However, according to the pressure-sensitive adhesive layer in the present embodiment, the adhesive force is high also to the acrylic resin, and the stress relaxation property is excellent. Therefore, it is excellent in durability even under high temperature conditions, under moist heat conditions, under heat shock, and the like. In addition, the "acrylic resin layer formed through extrusion molding" also includes an acrylic resin layer obtained by performing an stretching treatment after extrusion molding.

The optical film in the present embodiment is preferably provided with at least an acrylic resin layer and a phase difference plate having a phase difference expression layer, and the phase difference expression layer is a styrenic resin from the viewpoint of making thin film and phase difference expression compatible. It is preferable to consist of Moreover, it is preferable that the said retardation plate has a 2nd acrylic resin layer on the surface side opposite to the surface on the acrylic resin layer side in the said phase difference expression layer. In this way, by having an acrylic resin layer and a retardation developing layer composed of a styrene resin, and further having a second acrylic resin layer, in a liquid crystal display device, particularly an IPS (In-Place-Switching) mode liquid crystal display device, Excellent viewing angle compensation performance can be exhibited.

It is preferable that a second retardation plate is further laminated on a side of the retardation plate opposite to the surface of the pressure-sensitive adhesive layer, and the second retardation plate is preferably made of a cycloolefin-based resin. By having such a 2nd retardation plate and by extension having the 2nd retardation plate which consists of cycloolefin type-resin, the viewing angle compensation performance becomes a thing more excellent.

Further, it is preferable that a polarizing plate is further laminated on a side of a surface of the second retardation film opposite to the surface on the side of the retardation film. Thus, a composite polarizing plate having very good viewing angle compensation performance can be provided.

[Specific examples of optical films with pressure-sensitive adhesive layers]

1. Example where the optical film is a polarizer

An example of the optical film with a pressure-sensitive adhesive layer according to the present embodiment in a case where the optical film is a polarizing plate will be described with reference to FIG. 1 . As shown in FIG. 1, the optical film 10A with an adhesive layer according to this embodiment includes a polarizing plate 2A and an adhesive layer laminated on one surface (the lower surface in FIG. 1) of the polarizing plate 2A ( 1). In addition, although not shown, the peeling sheet may be laminated|stacked on the surface on the opposite side to the polarizing plate 2A side in the adhesive layer 1 until 10 A of optical films with an adhesive layer are used.

The pressure-sensitive adhesive layer 1 is composed of a pressure-sensitive adhesive obtained from the pressure-sensitive adhesive composition (P) described above.

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 (an upper surface in FIG. 1), and a polarizer 21 It is constituted by providing the second protective layer 23 laminated on the other side (the lower side in FIG. 1) of the . In addition, although not shown, an adhesive bond layer may be interposed between the polarizer 21 and the 1st protective layer 22 and/or between the polarizer 21 and the 2nd protective layer 23.

(1) Polarizer

The polarizer 21 is preferably composed 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 a 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 with this. As another monomer copolymerized with vinyl acetate, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids etc. are mentioned, for example.

The degree of saponification of the polyvinyl alcohol-based resin is usually 85 to 100 mol%, preferably 98 to 100 mol%. The polyvinyl alcohol-based resin may be further modified, and for example, polyvinyl formal and polyvinyl acetal modified with aldehydes can 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, and adsorption of the dichroic dye. It is preferably manufactured by passing through a step of treating the polyvinyl alcohol-based resin film with a boric acid aqueous solution.

Uniaxial stretching may be performed before dyeing with the dichroic dye, may be performed simultaneously with dyeing with the dichroic dye, or may be performed after dyeing with the dichroic dye. When uniaxial stretching is performed after dyeing with a dichroic dye, this uniaxial stretching may be performed before boric acid treatment or may be performed during boric acid treatment. Further, of course, it is also possible to perform uniaxial stretching in these plurality of steps. In order to uniaxially stretch, you may stretch uniaxially between rolls with different circumferential speeds, or you may stretch uniaxially using a hot roll. Further, dry stretching in which stretching is performed in air may be used, or wet stretching in which stretching is performed in a state swollen with a solvent may be used. A draw ratio is about 4 to 8 times normally.

What is necessary is just to immerse a polyvinyl alcohol-type resin film in the aqueous solution containing a dichroic dye, in order to dye a polyvinyl alcohol-type resin film with a dichroic dye, for example. As the dichroic dye, iodine or dichroic organic dye is specifically used.

When using iodine as a dichroic dye, a method of dyeing by immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide is usually adopted. The content of iodine 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. The temperature of this aqueous solution is usually about 20 to 40°C, and the immersion time (dyeing time) in this aqueous solution is usually about 30 to 300 seconds.

The boric acid treatment after dyeing with the dichroic dye is performed by immersing the dyed polyvinyl alcohol-based resin film in boric acid aqueous solution. The content of boric acid in the aqueous solution of boric acid 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 using iodine as a dichroic dye, it is preferable that this boric acid aqueous solution contains potassium iodide. The content of potassium iodide in the aqueous solution of boric acid 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 by, for example, immersing the polyvinyl alcohol-based resin film treated with boric acid in water. After water washing, a drying process is performed and the polarizer 21 is obtained. The water temperature in the water washing treatment is usually about 5 to 40°C, and the immersion time is usually about 2 to 120 seconds. The drying treatment performed thereafter is usually performed using a hot air dryer or a far-infrared heater. Drying temperature is 40-100 degreeC normally. Moreover, the time of a drying process is about 120 to 600 second normally.

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

(2) protective layer

It is preferable that the 1st protective layer 22 and the 2nd protective layer 23 (it may be generically called "protective layers 22 and 23" below) consist of a transparent resin film. The transparent resin film constituting the protective layers 22 and 23 may be either an unstretched 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 one selected from the group consisting of polyester-based resins, polycarbonate-based resins, acrylic resins, amorphous polyolefin-based resins, and cellulose-based resins. It is one type of resin. It is preferable that the 1st protective layer 22 consists of a cellulose-type resin among the above.

The cellulose-based resin may be a resin in which at least one part of the hydroxyl group in the cellulose is acetic acid esterified, a mixed ester in which one part is acetic acid esterified and one part is esterified with another acid. The cellulose-based resin is preferably a cellulose ester-based resin, and more preferably an acetyl cellulose-based resin. Specific examples of the acetyl cellulose-based resin include triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, and cellulose acetate butylate. Examples of commercially available films made of such an acetyl cellulose resin include “Fujitac TD80”, “Fujitac TD80UF” and “Fujitac TD80UZ” manufactured by Fujifilm Co., Ltd., manufactured by Konica Minolta Opto Co., Ltd. "KC8UX2M", "KC2UA", and "KC8UY" of

A cellulose-based resin film endowed with an optical compensation function may also be used. As such an optical compensation film, for example, a film in which a compound having a retardation adjusting function is incorporated into a cellulose resin, a compound having a retardation adjusting function applied to the surface of a cellulose resin, and a uniaxial or biaxial cellulose resin and films obtained by stretching. Examples of commercially available cellulose-based resin optical compensation films include "Wideview Film WV BZ 438" and "Wideview Film WV EA" manufactured by Fujifilm Co., Ltd., and "KC4FR-" manufactured by Konica Minolta Opto Co., Ltd. 1” and “KC4HR-1”.

Among the above cellulose resins, the first protective layer 22 is more preferably made of a cellulose ester type resin, particularly preferably made of an acetyl cellulose type resin, and still more preferably made of a 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. In particular, the second protective layer 23 does not impair polarization performance and is easily thinned from the viewpoint of It is preferable to consist 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, low-molecular-weight components in the pressure-sensitive adhesive are sucked out, and the adhesiveness of the interface between the second protective layer 23 and the pressure-sensitive adhesive layer is reduced. will make However, in the case of the pressure-sensitive adhesive layer 1 formed from the pressure-sensitive adhesive composition (P) in the present embodiment, a (meth)acrylic acid ester copolymer (A) having a glass transition temperature (Tg) so high that the adhesive strength is not insufficient is used. In addition, by suppressing the content of the low molecular weight component to 5% by mass or less, the suction of the low molecular weight component from the pressure-sensitive adhesive layer 1 to the second protective layer 23 can be effectively suppressed. As a result, the adhesiveness of the pressure-sensitive adhesive layer 1 to the second protective layer 23 is increased. Therefore, 10 A of said optical films with an adhesive layer become what was excellent in durability also under high temperature conditions, under wet heat conditions, under heat shock, etc.

The acrylic resin forming the second protective layer 23 is preferably a polymer containing methacrylic acid ester as a main monomer, and particularly preferably a copolymer in which a small amount of other comonomer components are copolymerized. This copolymer can usually be obtained by polymerizing monofunctional monomers containing methyl methacrylate and methyl acrylate in the presence of a radical polymerization initiator and a chain transfer agent. Moreover, acrylic resin can copolymerize a 3rd monofunctional monomer.

Examples of the third monofunctional monomer copolymerizable with methyl methacrylate and methyl acrylate include ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, methacrylic acid esters other than methyl methacrylate, such as 2-ethylhexyl methacrylate and 2-hydroxyethyl methacrylate; acrylic esters such as ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl acrylate; Hydroxyalkyl acrylate esters such as 2-(hydroxymethyl)methyl acrylate, 2-(1-hydroxyethyl)methyl acrylate, 2-(hydroxymethyl)ethyl acrylate, and 2-(hydroxymethyl)butyl acrylate ; unsaturated acids such as methacrylic acid and acrylic acid; halogenated styrenes such as chlorostyrene and bromostyrene; substituted styrenes such as vinyltoluene and α-methylstyrene; unsaturated nitriles such as acrylonitrile and methacrylonitrile; unsaturated acid anhydrides such as maleic anhydride and citraconic anhydride; and unsaturated imides such as phenyl maleimide and cyclohexyl maleimide. These may be used independently, respectively, and different multiple types may be used together.

When copolymerizing a polyfunctional monomer, examples of the polyfunctional monomer copolymerizable with methyl methacrylate and methyl acrylate include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tri Both ends of ethylene glycol such as ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, nonaethylene glycol di(meth)acrylate, and tetradecaethylene glycol di(meth)acrylate or oligomers thereof What esterified a hydroxyl group with acrylic acid or methacrylic acid; What esterified the hydroxyl groups of both ends of propylene glycol or its oligomer with acrylic acid or methacrylic acid; What esterified the hydroxyl group of dihydric alcohols, such as neopentyl glycol di(meth)acrylate, hexanediol di(meth)acrylate, and butanediol di(meth)acrylate, with acrylic acid or methacrylic acid; bisphenol A, alkylene oxide adducts of bisphenol A, or those obtained by esterifying the hydroxyl groups at both terminals of halogen-substituted products thereof with acrylic acid or methacrylic acid; those obtained by esterifying polyhydric alcohols such as trimethylolpropane and pentaerythritol with acrylic acid or methacrylic acid, and ring-opening additions of epoxy groups of glycidyl acrylate or glycidyl methacrylate to these terminal hydroxyl groups; dibasic acids such as succinic acid, adipic acid, terephthalic acid, phthalic acid, halogen-substituted products thereof, and alkylene oxide adducts thereof with ring-opening addition of an epoxy group of glycidyl acrylate or glycidyl methacrylate; aryl (meth)acrylate; Aromatic divinyl compounds, such as divinylbenzene, etc. are mentioned. Among them, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and neopentyl glycol dimethacrylate are preferably used.

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

It is preferable that the range of the glass transition temperature (Tg) of the said acrylic resin is 80-120 degreeC. In order to adjust the glass transition temperature (Tg) of the acrylic resin to the above range, usually, the polymerization ratio of the methacrylic acid ester monomer and the acrylic acid ester monomer, the carbon chain length of each ester group and the kind of functional group it has, and the monomer A method of appropriately selecting the polymerization ratio of the polyfunctional acrylic monomer with respect to the whole, and the like are employed.

Acrylic resin may contain a well-known additive as needed. Examples of known additives include lubricants, antiblocking agents, heat stabilizers, antioxidants, antistatic agents, light resistance agents, impact resistance modifiers, and surfactants. However, since transparency is required as a protective film laminated on a 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 calendering method may be used. Among them, a method in which raw resin is melt-extruded from a T-die, and at least one side of the obtained film-like material is brought into contact with a roll or belt to form a film is preferable from the viewpoint of obtaining a film with good surface properties.

The acrylic resin may contain acrylic rubber particles as an impact improving agent from the viewpoint of the film forming property of the film and the impact resistance of the film. The acrylic rubber particles as used herein are particles containing an acrylic acid ester-based elastic polymer as an essential component, and those having a homogeneous particle form with this elastic polymer or those having a multilayer structure with one layer of this elastic polymer are mentioned. can

As an example of such an elastic polymer, the crosslinked elastic copolymer which has alkyl acrylate as a main component and copolymerized another vinyl monomer and a crosslinkable monomer copolymerizable with this is mentioned. Examples of the alkyl acrylate serving as the main component of the elastomer include methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, and the like, in which the number of carbon atoms in the alkyl group is about 1 to 8, In particular, acrylates having an alkyl group having 4 or more carbon atoms are preferably used. Other vinyl monomers copolymerizable with this alkyl acrylate include compounds having one polymerizable carbon-carbon double bond in the molecule, more specifically, methacrylic acid esters such as methyl methacrylate, styrene, etc. aromatic vinyl compounds of , vinyl cyan compounds such as acrylonitrile, and the like. Further, examples of the crosslinkable monomer include crosslinkable compounds having at least two polymerizable carbon-carbon double bonds in the molecule, more specifically, ethylene glycol di(meth)acrylate and butanedioldi(meth)acrylate (meth)acrylates of polyhydric alcohols such as late, alkenyl esters of (meth)acrylic acid such as allyl (meth)acrylate, and divinylbenzene.

Further, a laminate of a film made of acrylic resin not containing rubber particles and a film made of acrylic resin containing rubber particles can also be used as the protective layers 22 and 23 . Acrylic resins can be easily obtained commercially, for example, as trade names, respectively, Smipex (manufactured by Sumitomo Chemical Co., Ltd.), Acripet (manufactured by Mitsubishi Rayon Co., Ltd.), Derpet (Asahi Kasei Co., Ltd.) (manufactured by Co., Ltd.), Parapet (manufactured by Kuraray Co., Ltd.), Ac Reviewa (manufactured by Nippon Shokubai Co., Ltd.), and the like.

The protective layers 22 and 23 may contain a ultraviolet absorber. It is because the liquid crystal cell can be protected from deterioration by ultraviolet rays by disposing the protective layer containing a ultraviolet absorber on the visible side of the liquid crystal cell.

Here, the 1st protective layer 22 and the 2nd protective layer 23 may consist of the same type of transparent resin film, or may consist of different types of transparent resin films.

Prior to bonding to the polarizer 21, the protective layers 22 and 23 may be subjected to easy adhesion treatment such as saponification treatment, corona treatment, priming treatment, anchor coating treatment, etc. on the bonding surface. Moreover, you may have various processing layers, such as a hard-coat layer, an antireflection layer, and an anti-glare layer, on the surface of the protective layers 22 and 23 opposite to the bonding surface with respect to the polarizer 21.

The thickness of the protective layers 22 and 23 is usually in the range of about 5 to 200 μm, preferably 10 to 120 μm, particularly preferably 10 to 85 μm, and still more preferably 10 to 30 μm.

(3) adhesive layer

As an adhesive constituting the 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, depending on the type and purpose of the adherend Accordingly, an appropriate one can be used appropriately. Examples thereof include solvent-type adhesives, emulsion-type adhesives, water-based adhesives, pressure-sensitive adhesives, rewritable adhesives, polycondensation-type adhesives, solvent-free adhesives, film adhesives, and hot-melt adhesives.

One preferable adhesive constituting the adhesive is a water-based adhesive, and a typical example thereof is one having a polyvinyl alcohol-based resin as a main component. Commercially available polyvinyl alcohol-based resins that can be used as water-based adhesives include, for example, "KL-318" manufactured by Kuraray Co., Ltd.

The water-based adhesive may contain a crosslinking agent. As a crosslinking agent, an amine compound, an aldehyde compound, a methylol compound, an epoxy compound, an isocyanate compound, a polyvalent metal salt, etc. are preferable, and an epoxy compound is especially preferable. Commercially available products of the crosslinking agent include, for example, glyoxal and "Sumilaze Resin 650 (30)" which is an aqueous solution of a water-soluble epoxy compound sold from Sumica Chemtex Co., Ltd.

As another preferred adhesive, an adhesive composed of an epoxy-based resin composition containing an epoxy resin that is cured by irradiation with active energy rays or heating is exemplified. In the case of using the adhesive, adhesion between films can be performed by curing the curable epoxy resin contained in the adhesive by irradiating an active energy ray or heating the adhesive layer interposed between the films. Curing of the epoxy resin by active energy ray irradiation or heating is preferably performed by cationic polymerization of the epoxy resin. In addition, in this specification, an epoxy resin means a compound having two or more epoxy groups in a molecule.

From the viewpoints of weather resistance, refractive index, cationic polymerization and the like, the epoxy resin contained in the curable epoxy resin composition as an adhesive is preferably an epoxy resin containing no aromatic ring in its molecule. As such an epoxy resin, a hydrogenated epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin, etc. can be illustrated.

(4) Manufacturing method of polarizing plate

Manufacture of 2 A of polarizing plates can be performed by a conventional method. Hereinafter, as an example, a manufacturing method in the case of using a water-based adhesive as the adhesive is described.

Initially, an adhesive bond layer is formed in the bonding surface of the polarizer 21 or the bonding surface of the protective layers 22 and 23. For formation of 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, or the like can be used. Moreover, the method of casting an adhesive agent in between is also employable, supplying continuously the polarizer 21 and the protective layers 22 and 23 so that both bonding surfaces may become inside. After the adhesive has been applied, heat treatment is performed as necessary to evaporate moisture and the adhesive layer is dried.

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

In adhering the polarizer 21 and the protective layers 22 and 23, corona discharge treatment, plasma treatment, flame treatment, priming, anchoring, before forming the application layer of the adhesive agent on one or both of the bonding surfaces of both An easy adhesion treatment such as a coating treatment may be performed.

When the adhesive layer is formed as described above, the first protective layer 22 is bonded to one surface of the polarizer 21 through the adhesive layer, and the second protective layer 23 is attached to the polarizer 21 ) is bonded to the other side of Thereby, 2 A of polarizing plates formed by laminating|stacking the 1st protective layer 22, the polarizer 21, and the 2nd protective layer 23 are obtained.

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

(5) Manufacturing method of an optical film with an adhesive layer

As a preferable example of the manufacturing method of optical film with an adhesive layer 10A, the adhesive sheet formed by laminating|stacking a peeling sheet on the single side|surface or both surfaces of the adhesive layer formed from adhesive composition (P) is manufactured first. Here, as an example, a pressure-sensitive adhesive sheet formed by laminating release sheets on both surfaces of the pressure-sensitive adhesive layer is manufactured.

Examples of the release sheet include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film, a polyethylene naphthalate film, 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 A film, a fluororesin film, or the like is used. Moreover, these crosslinked films are also used. Moreover, these laminated|multilayer films may be sufficient.

It is preferable that at least one surface of the release sheet (particularly, a 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, silicone, fluorine, unsaturated polyester, polyolefin, and wax release agents. In addition, the release surface of a release sheet in this specification refers to the surface which has release property in a release sheet, and includes both the surface on which the release process was performed and the surface which exhibits release property even without the release process.

When the release sheet is laminated 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.

In one example of the method for manufacturing the pressure-sensitive adhesive sheet, a coating solution of the adhesive composition (P) is applied to the release surface of the release sheet, and a coating film is formed by heat treatment. A release sheet (so that the release surface is in contact with the coating film) or a substrate is laminated. When the curing period is unnecessary, the coating film becomes an adhesive layer as it is, and when a curing period is required, it becomes an adhesive layer after the curing period has elapsed. Heat treatment and curing conditions are as described above.

As a method of 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, or the like can be used.

One release sheet (light release type release sheet) is peeled from the adhesive sheet obtained in the above manner. Then, the second protective layer 23 of the polarizing plate 2A is overlaid on the exposed pressure-sensitive adhesive layer, and the pressure-sensitive adhesive sheet and the polarizing plate 2A are pressed. Thereby, the said optical film 10A with an adhesive layer (with a release sheet) is obtained.

In another example of the manufacturing method of the optical film with an adhesive layer 10A, a solution (coating solution) containing the above-mentioned adhesive composition (P) is applied to a release surface of a release sheet, and a coating film is formed by heat treatment. After that, the second protective layer 23 of the polarizing plate 2A is overlaid on the coated film. When a curing period is required, a curing period is provided, and when a curing period is unnecessary, the coating film becomes the pressure-sensitive adhesive layer 1 as it is. Thereby, the said optical film 10A with an adhesive layer (with a release sheet) is obtained.

2. Example in which the optical film is a composite polarizer

An example of the optical film with a pressure-sensitive adhesive layer according to the present embodiment in a case where the optical film is a composite polarizing plate having a retardation plate will be described with reference to FIG. 2 . As shown in FIG. 2 , the optical film 10B with an adhesive layer according to this embodiment includes a composite polarizing plate 2B and an adhesive laminated on one surface (the lower surface in FIG. 2 ) of the composite polarizing plate 2B. It is constituted with layer (1). In addition, although not shown, the peeling sheet may be laminated|stacked on the surface on the opposite side to the composite polarizing plate 2B side in the adhesive layer 1 until the optical film 10B with an adhesive layer is used.

The pressure-sensitive adhesive layer 1 is composed of a pressure-sensitive adhesive obtained from the pressure-sensitive adhesive composition (P) described above.

The composite polarizing plate 2B in the present embodiment has the first retardation plate 24 in contact with the pressure-sensitive adhesive layer 1 and the side opposite to the pressure-sensitive adhesive layer 1 side in the first retardation plate 24. The second retardation plate 25 positioned thereon, the second pressure-sensitive adhesive layer 26 interposed between the first retardation plate 24 and the second retardation plate 25, and the second retardation plate 25 2 It is configured to include a polarizer 21 laminated on the opposite side to the pressure-sensitive adhesive layer 26 side and a protective layer 27 laminated on the opposite side to the second retardation plate 25 side in the polarizer 21. . 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 . This composite polarizing plate 2B satisfactorily exhibits viewing angle compensation performance.

(1) First retardation plate

The first retardation plate 24 may consist of a single layer that exhibits a phase difference, or may consist of a plurality of layers including a phase difference expression layer. This first retardation plate 24 is preferably laminated on the phase difference expression layer 242 and one surface of the phase difference expression layer 242 (the lower surface in FIG. 3 ), as shown in FIG. 3 . It is comprised by providing the 1st acrylic resin layer 241 and the 2nd acrylic resin layer 243 laminated|stacked on the other surface (upper surface in FIG. 3) of the retardation expression layer 242. The phase difference expression layer 242 has a negative intrinsic birefringence and is preferably made of a styrenic resin from the viewpoint of easy thinning. Thus, a composite polarizing plate having a first retardation plate 24 comprising a first acrylic resin layer 241, a retardation developing layer 242 made of styrene resin, and a second acrylic resin layer 243, (2B) is excellent in the performance of viewing angle compensation of a liquid crystal display device, especially an IPS (In-Place-Switching) mode liquid crystal display device. In addition, since the phase difference expression layer 242 is protected by the first acrylic resin layer 241 and the second acrylic resin layer 243 present on both surfaces thereof, the first phase difference plate 24 is a phase difference expression layer ( 242) does not impair the optical performance and has excellent mechanical strength and chemical resistance.

In addition, 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 composition. In the layer formed, low-molecular-weight components in the pressure-sensitive adhesive are sucked out, and the adhesiveness of the interface between the first acrylic resin layer 241 and the pressure-sensitive adhesive layer is reduced. However, in the case of the pressure-sensitive adhesive layer 1 formed from the pressure-sensitive adhesive composition (P) in the present embodiment, a (meth)acrylic acid ester copolymer (A) having a glass transition temperature (Tg) so high that the adhesive strength is not insufficient is used. In addition, by suppressing the content of the low molecular weight component to 5% by mass or less, the suction of the low molecular weight component from the pressure-sensitive adhesive layer 1 to the first acrylic resin layer 241 can be effectively suppressed. In this way, the adhesiveness of the pressure-sensitive adhesive layer 1 to the first retardation plate 24 is increased. Therefore, the said optical film 10B with an adhesive layer becomes what was excellent in durability also under high-temperature conditions, under moist-heat conditions, under heat shock, etc.

In addition, it is preferable that the first retardation plate 24 is one to which in-plane retardation is imparted by stretching. This makes the performance of viewing angle compensation more excellent.

The styrene resin constituting the phase difference expression layer 242 may be a homopolymer of styrene or a derivative thereof, or a binary or higher copolymer of styrene or a derivative thereof and another copolymerizable monomer. A styrene derivative is a compound in which another group is bonded to styrene, for example, an alkyl such as o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, o-ethylstyrene, or p-ethylstyrene. substituted styrene in which a hydroxyl group, an alkoxy group, a carboxyl group, a halogen, etc. is introduced into the benzene nucleus of styrene, such as styrene, hydroxystyrene, tert-butoxystyrene, vinylbenzoic acid, o-chlorostyrene, and p-chlorostyrene; can

As the styrenic resin, a terpolymer as disclosed in Japanese Unexamined Patent Publication No. 2003-50316 or Japanese Unexamined Patent Publication No. 2003-207640 can also be used.

The styrenic resin constituting the phase difference expression 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.

Moreover, as a styrene-type resin which comprises the phase difference expression layer 242, the styrene-type resin which has heat resistance is preferable. Although the glass transition temperature (Tg) of a styrenic resin is generally 100°C or higher, a styrenic resin having a glass transition temperature (Tg) of 120°C or higher is preferred.

It is preferable that the thickness of phase difference expression layer 242 is 10-100 micrometers. When the thickness of the phase difference 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 phase difference expression layer 242 is 100 μm or less, the impact strength is high, the retardation change due to external stress is small, and when applied to a liquid crystal display device, heat unevenness or the like does not occur easily.

It is preferable that the 1st acrylic resin layer 241 and the 2nd acrylic resin layer 243 consist of a (meth)acrylic resin composition in which rubber particles are mix|blended with (meth)acrylic resin. By blending the rubber particles, the impact resistance of the acrylic resin layer can be improved.

As (meth)acrylic-type resin, the homopolymer of methacrylic acid alkylester or acrylic acid alkylester, the copolymer of methacrylic acid alkylester and acrylic acid alkylester, etc. are mentioned, for example. Examples of methacrylic acid alkyl esters include methyl methacrylate, ethyl methacrylate, and propyl methacrylate. Moreover, methyl acrylate, ethyl acrylate, propyl acrylate etc. are mentioned as acrylic acid alkylester. What is marketed as a general-purpose (meth)acrylic-type resin can be used for such (meth)acrylic-type resin. Further, (meth)acrylic resins include what are called impact-resistant (meth)acrylic resins and what are called highly heat-resistant (meth)acrylic resins having a glutaric anhydride structure or a lactone ring structure in the main chain.

The rubber particles blended with the (meth)acrylic resin are preferably of an acrylic type. Acrylic 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 made of a material having rubber elasticity in the form of homogeneous particles, or may be a multilayer structure having at least one rubber elastic layer. As the acrylic rubber particles having a multilayer structure, a particle having rubber elasticity as described above is used as a nucleus and the periphery thereof is covered with a hard methacrylic acid alkyl ester-based polymer, and a hard methacrylic acid alkyl ester-based polymer is used as a nucleus. and covering the periphery with the acrylic polymer having rubber elasticity as described above, and covering the periphery of the hard core with the acrylic polymer having rubber elasticity, and further covering the periphery with a hard methacrylic acid alkylester-based polymer. etc. can be mentioned.

The average diameter of the rubber particles is preferably about 50 to 400 nm. The average diameter of rubber particles can be measured by a 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 50 parts by mass per 100 parts by mass of the (meth)acrylic resin It is desirable that the degree

As the (meth)acrylic resin composition constituting the first acrylic resin layer 241 and the second acrylic resin layer 243, a commercially available mixture of (meth)acrylic resin and acrylic rubber particles can be used. . Examples of commercially available (meth)acrylic resins ((meth)acrylic resin compositions) containing acrylic rubber particles include "HT55X" and "Technoloy S001" sold by Sumitomo Chemical Co., Ltd. under trade names. can

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 preferred, and particularly 110°C or lower (meth)acrylic resin composition. An acrylic resin composition is preferred. That is, it is preferable that the glass transition temperature (Tg) of the phase difference expression 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 phase difference expression It is preferable that the layer 242 has a glass transition temperature (Tg) higher than that of the first acrylic resin layer 241 and the second acrylic resin layer 243 .

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

It is preferable that the thickness of the 1st acrylic resin layer 241 and the 2nd acrylic resin layer 243 is 10-100 micrometers, respectively. If the thickness is 10 μm or more, it can be easily formed into a film, and if the thickness is 100 μm or less, retardation of the first acrylic resin layer 241 and the second acrylic resin layer 243 can be disregarded. In addition, it is preferable that the thickness of the 1st acrylic resin layer 241 and the thickness of the 2nd acrylic resin layer 243 are substantially the same.

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

To manufacture the first retardation plate 24, for example, a (meth)acrylic resin composition in which a styrene-based resin and rubber particles are blended may be co-extruded and then stretched. Stretching can be carried out by longitudinal uniaxial stretching, tenter transverse uniaxial stretching, simultaneous biaxial stretching or sequential biaxial stretching, or the like, and may be stretched so as to obtain a desired retardation value. In addition to the above method, after producing single-layer films (phase difference expression layer 242, first acrylic resin layer 241, and second acrylic resin layer 243), heat lamination is performed to heat-seal them, and the lamination is performed. The sieve may be stretched.

In addition, the total thickness of the first retardation plate 24 after stretching is preferably 5 to 100 μm, and more preferably 10 to 50 μm, from the viewpoint of meeting the demand for thinning in mobile applications while maintaining sufficient performance. It is preferable, and it is especially preferable that it is 15-30 micrometers.

In the first retardation plate 24, the surface in contact with the pressure-sensitive adhesive layer 1 is constituted by the first acrylic resin layer 241. Even in this case, the pressure-sensitive adhesive layer 1 is the first acrylic resin layer 241 ) is high, therefore, the optical film 10B with an adhesive layer is excellent in durability under high temperature conditions, under moist heat conditions, under heat shock, and the like.

(2) Second retardation plate

It is preferable that the 2nd retardation plate 25 consists of olefin resin. The olefin-based resin is a resin composed of structural units derived from chain-like aliphatic olefins such as ethylene and propylene, or alicyclic olefins such as norbornene and substituents thereof (hereinafter collectively referred to as norbornene-based monomers). The copolymer using 2 or more types of monomers may be sufficient as olefin type resin.

Among them, as the olefin resin, a cyclic olefin resin which is a resin mainly containing structural units derived from alicyclic olefins is preferably used. Typical examples of the alicyclic olefin constituting the cyclic olefin resin include norbornene monomers. Norbornene is a compound in which one carbon-carbon bond of norbornane has become a double bond, and is named bicyclo[2,2,1]hepto-2-ene according to the IUPAC nomenclature. Examples of substituents of norbornene include 3-substituents, 4-substituents, and 4,5-disubstituents in which the double bond position of norbornene is set to the 1,2-position, and dicyclopenta Dienes, dimethanooctahydronaphthalene, and the like can also be used as monomers constituting the cyclic olefin resin.

Cyclic olefin type resin may or may not have a norbornane ring in the structural unit. Examples of the norbornene-based monomer forming a cyclic olefin-based resin having no norbornane ring as a constituent unit include those that become a 5-membered ring by ring opening, typically norbornene and dicyclopenta Diene, 1- or 4-methylnorbornene, 4-phenyl norbornene, etc. are mentioned. When the cyclic olefin-based resin is a copolymer, the arrangement of its molecules is not particularly limited, and may be a random copolymer, a block copolymer, or a graft copolymer.

More specific examples of the cyclic olefin-based resin include, for example, ring-opening polymers of norbornene-based monomers, ring-opening copolymers of norbornene-based monomers and other monomers, and modified polymers obtained by adding maleic acid or adding cyclopentadiene to these. Water, polymers or copolymers obtained by hydrogenating these, addition polymers of norbornene-based monomers, addition copolymers of norbornene-based monomers and other monomers, and the like are exemplified. Examples of other monomers in the case of forming a copolymer include α-olefins, cycloalkenes, and non-conjugated dienes. Moreover, the copolymer using 1 type(s) or 2 or more types of a norbornene-type monomer and other alicyclic olefins may be sufficient as cyclic olefin type resin.

Among the 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-based resin can be made into a retardation plate by subjecting it to a stretching process, and in addition to stretching, a shrinkable film having a predetermined shrinkage rate is bonded to it and heat-shrinking is applied to achieve high uniformity, It is also possible to use a retardation plate having a large retardation value.

Commercially available products of cyclic olefin resins using norbornene monomers include "Zeonex" and "Zeonoa" sold by Nippon Zeon Co., Ltd., and "Aton" sold by JSR Co., Ltd. etc. Films of these cyclic olefin resins and stretched films thereof can also be obtained commercially, for example, "Zeonor Film" sold under a trade name from Nippon Zeon Co., Ltd., sold from JSR Co., Ltd. "Aton Film" sold by Sekisui Chemical Industry Co., Ltd., and "S Shinar" available.

In addition, for the second retardation plate 25, a film made of a mixed resin containing two or more types of olefin resin or a film made of a mixed resin of an olefin resin and another thermoplastic resin can also be used. For example, as mixed resin containing two or more types of olefin type resin, the mixture of above-mentioned cyclic olefin type resin and chain type aliphatic olefin type resin is mentioned. When using mixed resin of an olefin resin and another thermoplastic resin, another thermoplastic resin is suitably selected according to the purpose. Specific examples include polyvinyl chloride-based resins, cellulose-based resins, polystyrene-based resins, acrylonitrile/butadiene/styrene copolymer resins, acrylonitrile/styrene copolymer resins, (meth)acrylic resins, polyvinyl acetate-based resins, poly Vinylidene chloride-based resin, polyamide-based resin, polyacetal-based resin, polycarbonate-based resin, modified polyphenylene ether-based resin, polybutylene terephthalate-based resin, polyethylene terephthalate-based resin, polyphenylene sulfide-based resin, and polysulfone-based resins, polyethersulfone-based resins, polyether ether ketone-based resins, polyarylate-based resins, liquid crystalline resins, polyamideimide-based resins, polyimide-based resins, and polytetrafluoroethylene-based resins. . A thermoplastic resin can be used individually by 1 type or in combination of 2 or more types. Moreover, the said thermoplastic resin can also be used after performing arbitrary suitable polymer modification. Examples of polymer modification include copolymerization, crosslinking, molecular terminal modification, and provision of stereoregularity.

In the case of using a mixed resin of an olefinic resin and another thermoplastic resin, the content of the other thermoplastic resin is usually about 50% by mass or less, preferably about 40% by mass or less, with respect to the entire resin. By setting the content of the other thermoplastic resin within this range, a retardation plate having a small absolute value of the photoelastic coefficient, exhibiting good wavelength dispersion characteristics, and excellent durability, mechanical strength and transparency can be obtained.

Olefin resin can be formed into a film by a casting method from a solution, a melt extrusion method, or the like. In the case of forming a film from two or more types of mixed resin, the film forming method is not particularly limited, and for example, a film is produced by a casting method using a homogeneous solution obtained by stirring and mixing the resin component with a solvent in a predetermined ratio. method, a method of melt-mixing resin components at a predetermined ratio and producing a film by a melt extrusion method, and the like are employed.

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, as necessary. Moreover, in order to make surface roughness small, you may contain a leveling agent.

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 formula (1) when the refractive indices in the in-plane slow axis direction, the in-plane fast axis direction, and the thickness direction are n _x , n _y , and n _z , respectively, and the thickness of the film is d . :

R _e = (n _x - n _y ) × d (1)

The in-plane retardation value (R _e ) at a wavelength of 590 nm defined by is 30 to 150 nm, and the following formula (2):

Nz coefficient = (n _x - n _z )/(n _x - n _y ) (2)

It is preferable to have a refractive index anisotropy in which the Nz coefficient defined by is greater than 1 and less than 2.

The second retardation plate 25 having the above refractive index anisotropy can be obtained by longitudinal uniaxial stretching, tenter transverse uniaxial stretching, simultaneous biaxial stretching or sequential biaxial stretching of the film made of the olefin resin, A desired refractive index anisotropy can be obtained by appropriately selecting various temperatures such as preheating temperature, stretching temperature, heat set temperature, cooling temperature, and pattern during stretching in addition to appropriately adjusting the stretching ratio and stretching speed.

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

(3) 2nd adhesive layer

As the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer 26, a known pressure-sensitive adhesive can be used, and a curable pressure-sensitive adhesive or a non-curable pressure-sensitive adhesive may be used. It is preferable to use an energy ray-curable adhesive.

The active-energy ray-curable pressure-sensitive adhesive may have a polymer having active energy ray-curable property as a main component, or one containing as a main component a mixture of a polymer having no active energy ray-curable property and an active energy ray-curable polyfunctional monomer and/or oligomer. It can be done. Further, it may be a mixture of a polymer having active energy ray curing properties and a polymer having no active energy ray curing property, or a mixture of a polymer having active energy ray curing properties and a polyfunctional monomer and/or oligomer having active energy ray curing properties, and these three It may be a mixture of species.

Among the above, from the viewpoint of easiness to obtain an adhesive that exhibits cohesive force while maintaining adhesiveness, a mixture of a polymer without active energy ray curability and an active energy ray curable polyfunctional monomer and/or oligomer is preferable as a main component, In particular, it is preferable to use as a main component a mixture of a polymer having no active energy ray curability and a polyfunctional monomer having active energy ray curability.

As the polymer having no active energy ray curability, a (meth)acrylic acid ester polymer (hereinafter sometimes referred to as "(meth)acrylic acid ester polymer (X)") having no active energy ray curable group is preferable. The (meth)acrylic acid ester polymer (X) preferably contains a (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in an alkyl group as a monomer constituting the polymer. Thereby, the obtained adhesive can express desirable adhesiveness. Further, (meth)acrylic acid ester polymer (X) is a (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in an alkyl group, a monomer having a reactive functional group (reactive functional group-containing monomer), and other monomers used as desired It is particularly preferred that it is a copolymer of When the (meth)acrylic acid ester polymer (X) contains a reactive functional group-containing monomer as a monomer constituting the polymer, adhesion to a glass surface such as a liquid crystal cell can be improved, and a crosslinking agent (Z) described later and It may react to form a cross-linked structure.

Examples of (meth)acrylic acid alkyl esters having 1 to 20 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, and (meth)acrylate. n-pentyl acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, (meth)acrylic acid Myristyl, palmityl (meth)acrylate, stearyl (meth)acrylate, etc. are mentioned. Especially, from a viewpoint of further improving adhesiveness, (meth)acrylic acid ester of 1-8 carbon atoms of an alkyl group is preferable, and n-butyl (meth)acrylate is especially preferable. In addition, these may be used independently and may be used in combination of 2 or more type.

The (meth)acrylic acid ester polymer (X) preferably contains, as a monomer unit constituting the polymer, 50 to 99 mass% of (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group, particularly 60 to 99 It is preferable to contain by mass %, and also it is preferable to contain 70-98 mass %.

Preferred examples of the reactive functional group-containing monomer include monomers having a hydroxyl group in the molecule (hydroxyl group-containing monomers), monomers having a carboxyl group in the molecule (carboxyl group-containing monomers), and monomers having an amino group in the molecule (amino group-containing monomers). . These reactive functional group containing monomers may be used individually by 1 type, and may be used in combination of 2 or more type.

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

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. Especially, acrylic acid is preferable from the viewpoint of the reactivity of the carboxyl group in the obtained (meth)acrylic acid ester polymer (X) with the crosslinking agent (Z) and copolymerizability with other monomers. These may be used independently and may be used in combination of 2 or more type.

Examples of the amino group-containing monomer include aminoethyl (meth)acrylate and n-butylaminoethyl (meth)acrylate. These may be used independently and may be used in combination of 2 or more type.

The (meth)acrylic acid ester polymer (X) preferably contains 1 to 25% by mass of a reactive functional group-containing monomer as a monomer unit constituting the polymer, particularly preferably 1 to 20% by mass, and further It is preferable to contain 2-5 mass %.

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 to 3,000,000, particularly preferably 1,000,000 to 2,500,000, and more preferably 1,600,000 to 2,200,000.

In addition, (meth)acrylic acid ester polymer (X) may be used individually by 1 type, and may be used in combination of 2 or more type.

As the active energy ray-curable polyfunctional monomer (hereinafter sometimes referred to as "active energy ray-curable compound (Y)"), a polyfunctional acrylic having a molecular weight of 1000 or less that is excellent in compatibility with (meth)acrylic acid ester polymer (X) and the like. Rate-based monomers are preferred.

Examples of the polyfunctional acrylate-based monomer having a molecular weight of 1000 or less include 1,4-butanedioldi(meth)acrylate, 1,6-hexanedioldi(meth)acrylate, and neopentylglycoldi(meth)acrylate. Rate, polyethylene glycol di(meth)acrylate, neopentyl glycol adipate di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, dicyclopentanyl di(meth)acrylate, modified caprolactone bifunctional types such as dicyclopentenyl di(meth)acrylate, ethylene oxide-modified di(meth)acrylate, di(acryloxyethyl)isocyanurate, and allylated cyclohexyl di(meth)acrylate; Trimethylolpropane tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, propionic acid modified dipentaerythritol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, propylene oxide modified trimethylolpropane trifunctional types such as tri(meth)acrylate, tris(acryloxyethyl)isocyanurate, and ε-caprolactone modified tris(2-(meth)acryloxyethyl)isocyanurate; tetrafunctional types such as diglycerin tetra(meth)acrylate and pentaerythritol tetra(meth)acrylate; pentafunctional types such as propionic acid-modified dipentaerythritol penta(meth)acrylate; and hexafunctional types such as dipentaerythritol hexa(meth)acrylate and caprolactone-modified dipentaerythritol hexa(meth)acrylate. 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 to 50 parts by mass, particularly preferably 5 to 30 parts by mass, and more preferably 10 to 50 parts by mass, based on 100 parts by mass of the (meth)acrylic acid ester polymer (X). It is preferable that it is 20 mass parts.

It is also preferable that the said active energy ray-curable adhesive contains a crosslinking agent (Z). When the active energy ray-curable pressure-sensitive adhesive contains, as monomer units constituting the polymer, a (meth)acrylic acid ester polymer (X) containing a reactive functional group-containing monomer and a crosslinking agent (Z), when the pressure-sensitive adhesive is heated, the crosslinking agent (Z) reacts with the reactive functional group 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 acid ester polymer (X) is crosslinked by the crosslinking agent (Z) is formed, and the cohesive force of the resulting pressure-sensitive adhesive is improved.

The crosslinking agent (Z) may be one that reacts with the reactive functional group of the (meth)acrylic acid ester polymer (X), and examples thereof include isocyanate crosslinking agents, epoxy crosslinking agents, amine crosslinking agents, melamine crosslinking agents, aziridine crosslinking agents, and hydrazine. crosslinking agents, aldehyde crosslinking agents, oxazoline crosslinking agents, metal alkoxide crosslinking agents, metal chelate crosslinking agents, metal salt crosslinking agents, and ammonium salt crosslinking agents. As an isocyanate type crosslinking agent, the same thing as the crosslinking agent (B) mentioned above can be used. In addition, a crosslinking agent (Z) can be used individually by 1 type or in combination of 2 or more types.

The content of the crosslinking agent (Z) is preferably from 0.01 to 10 parts by mass, particularly preferably from 0.05 to 5 parts by mass, and more preferably from 0.1 to 1 part by mass, based on 100 parts by mass of the (meth)acrylic acid ester polymer (X). desirable.

The active energy ray-curable pressure-sensitive adhesive contains, as desired, various additives such as photopolymerization initiators, silane coupling agents, refractive index adjusters, antistatic agents, tackifiers, antioxidants, ultraviolet absorbers, light stabilizers, softeners, fillers, etc. You can do it.

When using an ultraviolet ray as an active energy ray for curing the active energy ray-curable pressure-sensitive adhesive, it is preferable that the active energy ray-curable pressure-sensitive adhesive contains a photopolymerization initiator.

Examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl Phenylketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2 -propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiary-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, Acetophenone dimethyl ketal, p-dimethylaminobenzoic acid ester, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], 2,4,6-trimethylbenzoyl-diphenyl - A phosphine oxide etc. are mentioned. These may be used independently and may be used in combination of 2 or more type.

The photopolymerization initiator is preferably used in an amount ranging from 0.1 to 20 parts by mass, particularly 1 to 12 parts by mass, based on 100 parts by mass of the active energy ray-curable compound (Y) in the active energy ray-curable pressure-sensitive adhesive.

Moreover, it is preferable that the said active energy ray-curable adhesive contains a silane coupling agent from a viewpoint of improving the adhesiveness with respect to the film of the adhesive obtained. The silane coupling agent is preferably an organosilicon compound having at least one alkoxysilyl group in its molecule, having good compatibility with an adhesive component and having light transmission properties.

Examples of such a silane coupling agent include vinyltrimethoxysilane, vinyltriethoxysilane, and methacryloxypropyl in addition to the above-mentioned epoxy group-containing silane coupling agent (C1) and mercapto group-containing silane coupling agent (C2). Polymerizable unsaturated group-containing silicon compounds such as trimethoxysilane, 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)- Amino group-containing silicon compounds such as 3-aminopropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, or at least one of these, methyltriethoxysilane, and ethyltriethoxy and condensates of alkyl group-containing silicon compounds such as silane, methyltrimethoxysilane, and 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 from 0.01 to 10 parts by mass, particularly preferably from 0.05 to 5 parts by mass, and more preferably from 0.1 to 1 part by mass, based on 100 parts by mass of the (meth)acrylic acid ester polymer (X). do.

The polymer having active energy ray curability is preferably 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 a side chain.

The thickness of the second pressure-sensitive adhesive layer 26 is usually about 1 to 50 μm, preferably 1 to 20 μm, and particularly preferably 2 to 7 μm. When the pressure-sensitive adhesive layer is too thin, the adhesiveness decreases, and when the pressure-sensitive adhesive layer is too thick, problems such as protrusion of the pressure-sensitive adhesive are likely to occur.

(4) Polarizer

As the polarizer 21, the same thing as the polarizer 21 of the above-mentioned polarizing plate 2A can be used.

(5) protective layer

It is preferable that the protective layer 27 consists of a transparent resin film. As this protective layer 27, the same thing as the 1st protective layer 22 in 2 A of polarizing plates can be used.

(6) adhesive layer

As 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, the same adhesive layer as that of the polarizing plate 2A described above can be used. have.

(7) Manufacturing method of composite polarizing plate

Manufacture of composite polarizing plate 2B can be performed by a conventional method. Hereinafter, as an example, a manufacturing method in the case of using a water-based adhesive as the adhesive is described.

First, a coated film of the pressure-sensitive adhesive constituting the second pressure-sensitive adhesive layer 26 is formed on the release 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 release surface of the release sheet and dried.

On the other hand, an adhesive bond layer is formed in the bonding surface of the polarizer 21 or the bonding surface of the 2nd retardation plate 25 and the protective layer 27. Formation of this adhesive bond layer can be performed by carrying out similarly to the method in the manufacturing method of the above-mentioned polarizing plate 2A. In addition, the thickness of the adhesive layer and the easy bonding treatment are also the same.

When the adhesive layer is formed as described above, while bonding the protective layer 27 to one surface of the polarizer 21 via the adhesive layer, the second retardation plate 25 of the polarizer 21 It is bonded to the other surface to obtain a laminate comprising the protective layer 27, the polarizer 21, and the second retardation plate 25.

Next, the coating film of the adhesive which comprises the 2nd adhesive layer 26 on the said release sheet is bonded to the surface of the obtained laminated body on the side of the 2nd retardation plate 25. Then, active energy rays are irradiated over the release sheet to cure the coated film of the pressure-sensitive adhesive, and the coated film is used as the second pressure-sensitive adhesive layer 26 .

Here, an active energy ray refers to an electromagnetic wave or a charged particle beam having energy quanta, and specific examples thereof include ultraviolet rays and electron beams. Among the active energy rays, ultraviolet rays are particularly preferred because they are easy to handle.

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 amount of irradiation of ultraviolet rays is preferably about 50 to 1000 mW/cm ² . Further, the amount of light is preferably 50 to 10000 mJ/cm ² , more preferably 80 to 5000 mJ/cm ² , and particularly preferably 100 to 1000 mJ/cm ² . On the other hand, electron beam irradiation can be performed by an electron beam accelerator or the like, and the amount of electron beam irradiation is preferably about 10 to 1000 krad.

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 applied to the exposed second pressure-sensitive adhesive layer 26. Glue the sides together. In this way, a composite polarizing plate 2B obtained by laminating the protective layer 27, the polarizer 21, the second retardation plate 25, the second pressure-sensitive adhesive layer 26, and the first retardation plate 24 is obtained.

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

(8) Manufacturing method of an optical film with an adhesive layer

As a preferable example of the manufacturing method of the optical film with an adhesive layer 10B, first, the adhesive sheet formed by laminating|stacking a peeling sheet on the single side|surface or both surfaces of the adhesive layer formed from adhesive composition (P) is manufactured. Here, as an example, a pressure-sensitive adhesive sheet formed by laminating release sheets on both surfaces of the pressure-sensitive adhesive layer is manufactured. This adhesive sheet can be manufactured by the method demonstrated in the manufacturing method of 10 A of optical films with an adhesive layer.

One release sheet (light release type release sheet) is peeled from the adhesive sheet obtained in the above manner. Then, the first retardation plate 24 of the composite polarizing plate 2B is superimposed on the exposed pressure-sensitive adhesive layer, and the pressure-sensitive adhesive sheet and the composite polarizing plate 2B are compressed. Thereby, the said optical film 10B with an adhesive layer (with a release sheet) is obtained.

In another example of the manufacturing method of the optical film with an adhesive layer 10B, the coating solution of the above-mentioned adhesive composition (P) is applied to the release surface of the release sheet, heat treatment is performed to form a coating film, and then the coating is applied. The first retardation plate 24 of the composite polarizing plate 2B is overlaid on the film. When a curing period is required, a curing period is provided, and when a curing period is unnecessary, the coating film becomes the pressure-sensitive adhesive layer 1 as it is. Thereby, the said optical film 10B with an adhesive layer (with a release sheet) is obtained.

3. Physical properties of optical film with pressure-sensitive adhesive layer

As for the adhesive force of the optical film 10A, 10B with an adhesive layer concerning this embodiment, it is preferable that the adhesive force with respect to alkali-free glass is 0.5-20 N/25 mm, and it is especially preferable that it is 1-10 N/25 mm do. Thereby, the optical film with an adhesive layer becomes a thing excellent in durability. Furthermore, it is preferable that the said adhesive force is 2-7 N/25 mm from a viewpoint of making it excellent also in reworkability. In addition, the adhesive force here refers to the adhesive force measured by the 180° peeling method based on JIS Z0237:2009 basically, but the measurement sample is 25 mm wide and 100 mm long, and the measurement sample is 0.5 mm with respect to the adherend. After pressurizing and sticking at MPa and 50°C for 20 minutes, after leaving it to stand for 24 hours under normal pressure, 23°C, and 50% RH conditions, the peeling rate is measured at 300 mm/min. When adhesive force exists in said range, when it affixes on a liquid crystal cell, lifting, peeling, etc. can be prevented.

Moreover, the optical film 10A, 10B with an adhesive layer concerning this embodiment is the adhesive force after being left to stand for 14 days further under conditions of 23 degreeC and 50%RH from sticking to the said adherend (Adhesive force after 14 days of sticking) It is preferable that it is 1-20 N/25 mm, and it is especially preferable that it is 3-9 N/25 mm. Thus, by suppressing the rise of the adhesive force by time passage, optical film 10A, 10B with an adhesive layer which concerns on this embodiment is also excellent in rework property, and can be easily re-sticked after sticking to a liquid crystal cell.

In addition, the optical film 10A, 10B with a pressure-sensitive adhesive layer according to the present embodiment has the adhesive strength after being left to stand for 2 days under conditions of 50°C and 50% RH from sticking to the adherend (adhesive strength after 2 days at 50°C) ) is preferably 1 to 20 N/25 mm from the viewpoint of durability, and particularly preferably 6 to 12 N/25 mm from the viewpoint of reworkability.

The surface resistivity of the pressure-sensitive adhesive layer in the optical film 10A, 10B with a pressure-sensitive adhesive layer according to the present embodiment is preferably 1.0 × 10 ¹² Ω/sq or less, particularly preferably 5.0 × 10 ¹¹ Ω/sq or less, Furthermore, it is preferable that it is 5.0 × 10 ¹⁰ Ω/sq or less. Sufficient antistatic property can be exhibited in a display panel because surface resistivity is below the said value. Such a surface resistivity becomes possible to achieve when adhesive composition (P) contains the above-mentioned antistatic agent (D). In addition, the surface resistivity of the pressure-sensitive adhesive layer is measured according to JIS K6911, and is specifically as shown in the test examples described later. In addition, the lower limit of the surface resistivity is not particularly limited, but is about 5.0 × 10 ⁸ Ω/sq from the viewpoint of not adversely affecting durability or nonuniformity in heat resistance.

4. Use of optical film with pressure-sensitive adhesive layer

By using optical films 10A and 10B with an adhesive layer, a liquid crystal display device provided with a liquid crystal cell and an optical film (a polarizing plate or composite polarizing plate) can be manufactured, for example.

Specifically, the pressure-sensitive adhesive layer (when the release sheet is laminated, the pressure-sensitive adhesive layer exposed by peeling the release sheet) of the optical films 10A and 10B with the pressure-sensitive adhesive layer is overlapped with respect to the desired surface of the liquid crystal cell, you have to squeeze Thereby, the liquid crystal display device provided with the liquid crystal cell, the polarizing plate 2A, and/or the composite polarizing plate 2B is obtained.

Since the adhesive layer 1 of the optical film 10A, 10B with an adhesive layer concerning this embodiment is excellent in durability, even if the obtained liquid crystal display device is under high temperature conditions, under moist heat conditions, or under heat shock, the adhesive layer ( 1) The occurrence of lifting or peeling at the interface of is suppressed. For example, when the glass plate to which the optical films 10A and 10B with an adhesive layer were affixed was subjected to a high temperature condition of 85 ° C., but under a moist heat condition of 60 ° C./90% RH for 250 hours, or -35 ° C. to 70 ° C. heat shock (30 minutes each, 200 cycles), the occurrence of lifting or peeling is suppressed.

Moreover, since the adhesive layer 1 of optical film 10A with an adhesive layer concerning this embodiment, 10B is also excellent in stress relaxation property, the obtained liquid crystal display device does not easily generate heat|fever nonuniformity. For example, even when the glass plate to which optical film 10A and 10B with an adhesive layer was affixed is placed under high-temperature conditions (for example, under 80 to 85°C conditions) for 250 hours, heat unevenness does not occur easily. In particular, even if the liquid crystal cell is a highly precise one, heat unevenness does not occur easily.

A transparent conductive film may exist on the surface of the liquid crystal cell with which the pressure-sensitive adhesive layer 1 contacts. Examples of such a 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. Complex oxides such as doped indium oxide, fluorine-doped indium oxide, antimony-doped tin oxide, fluorine-doped tin oxide, and aluminum-doped zinc oxide; non-oxidized compounds such as chalcogenide, lanthanum hexaboride, titanium nitride, and titanium carbide; can be heard

The embodiments described above are described for facilitating understanding of the present invention, and are not described to limit 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.

Example

Hereinafter, the present invention will be described more specifically by examples and the like, but the scope of the present invention is not limited to these examples and the like.

[Example 1]

1. Manufacture of optical film (composite polarizer)

(1) Fabrication of polarizer

A polyvinyl alcohol film with a thickness of 75 μm made of polyvinyl alcohol having an average degree of polymerization of about 2,400 and a degree of saponification of 99.9 mol% or more was uniaxially stretched about 5 times in a dry manner, and while maintaining a tensioned state, in pure water at 60 ° C. Soaked for minutes. Thereafter, 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, after washing with 26 degreeC pure water for 20 second, it dried at 65 degreeC and obtained the polarizer in which iodine adsorbed and oriented to polyvinyl alcohol.

(2) Production of a laminate including a protective layer, a polarizer, and a second retardation plate

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

To the coating layer of the epoxy adhesive, as a protective layer, a triacetyl cellulose film having a thickness of 25 μm (manufactured by Konica Minolta Opto Co., Ltd., trade name “KC2UA”) subjected to saponification treatment is bonded to the surface, and a protective layer and A laminate formed by laminating polarizers was obtained.

Next, an epoxy adhesive is applied to the other surface of the polarizer in the laminate in the same manner as above, and a cyclic olefin resin having a thickness of 23 μm is applied to the applied layer as a second retardation plate. The zero retardation film (Nippon Zeon Co., Ltd. product, brand name "ZEONOR") which consists of was bonded together. After that, the protective layer and the second retardation plate were bonded to the polarizer by drying at 80°C for 5 minutes. After bonding, curing at 40 ° C. for 168 hours, a protective layer (layer thickness: 25 μm), a polarizer (stretch ratio: 5 times, layer thickness: 15 μm), and a second retardation plate (layer thickness: 23 μm) are laminated to obtain a total thickness of 63 A layered body of μm was obtained.

(3) Formation of a coating film of an active energy ray-curable pressure-sensitive adhesive

95 parts by mass of n-butyl acrylate and 5 parts by mass of acrylic acid were copolymerized to prepare a (meth)acrylic acid ester polymer (X). As a result of measuring the molecular weight of this (meth)acrylic acid ester polymer (X) by the method described later, the weight average molecular weight (Mw) was 2,000,000.

100 parts by mass of the (meth)acrylic acid ester polymer (X) and tris(acryloxyethyl)isocyanurate (trade name “Aronix M- 315”) 15 parts by mass, trimethylolpropane-modified tolylene diisocyanate (manufactured by Nippon Polyurethane Industries, trade name “Colonate L”) as a crosslinking agent (Z), 0.3 parts by mass, and benzophenone and 1-hydroxycyclo as a polymerization initiator 1.5 parts by mass of a mixture of hexylphenyl ketone mixed at a mass ratio of 1:1 (manufactured by Chiba Specialty Chemicals, trade name "Irgacua 500") and 3-glycidoxypropyltrimethoxysilane (Shin-Etsu) as a silane coupling agent A coating solution of an active energy ray-curable pressure-sensitive adhesive was obtained by mixing 0.2 parts by mass of Chemical Industry Co., Ltd., trade name "KBM403", thoroughly stirring, and diluting with ethyl acetate.

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

(4) Fabrication of the first retardation plate

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 diameter of 200 nm constituting the first acrylic resin layer constitutes a phase difference expression layer A styrene-maleic anhydride-based copolymer resin (manufactured by Nova Chemical, trade name "Dyrac D332") and acrylic rubber particles having an average particle diameter of 200 nm constituting the second acrylic resin layer are blended in an amount of about 20% by mass. Three layers of resin (trade name "Technoloy S001" manufactured by Sumitomo Chemical Co., Ltd.) were co-extruded in this order to obtain a laminated film having a three-layer structure. The obtained laminated film was stretched to obtain a first retardation plate (first acrylic resin layer/phase difference expression layer/second acrylic resin layer) having an in-plane retardation value of 60 nm and a thickness of 25 µm.

(5) Fabrication of composite polarizer

The coating film of the active energy ray-curable pressure-sensitive adhesive obtained in the step (3) was bonded to the surface on the side of the second retardation plate in the laminate obtained in the step (2), and ultraviolet rays were irradiated over the release sheet under the following conditions, , the coating film of the pressure-sensitive adhesive was cured to obtain a second pressure-sensitive adhesive layer. After that, the release sheet is peeled off from the obtained second pressure sensitive adhesive layer, and the surface of the second acrylic resin layer side in the first phase difference plate obtained in the step (4) is bonded to the surface of the exposed second pressure sensitive adhesive layer. did In this way, a composite polarizing plate (optical film) having a total thickness of 93 µm formed by laminating the protective layer, the polarizer, the second retardation plate, the second pressure-sensitive adhesive layer, and the first retardation plate was obtained. In addition, the thickness of the formed 2nd adhesive layer was 5 micrometers.

<Ultraviolet irradiation conditions>

･Using a high-pressure mercury lamp

·Illuminance 300 mW/cm ² , Light quantity 300 mJ/cm ²

・The UV illuminance/light meter uses "UVPF-A1" manufactured by Eye Graphics.

2. Manufacture of optical film with pressure-sensitive adhesive layer

(1) Preparation of (meth)acrylic acid ester copolymer

87 parts by mass of n-butyl acrylate, 5 parts by mass of isobornyl acrylate, 5 parts by mass of 2-phenylethyl acrylate, and 3 parts by mass of 2-hydroxyethyl acrylate were copolymerized to prepare a (meth)acrylic acid ester copolymer (A). . As a result of measuring the molecular weight of this (meth)acrylic acid ester copolymer (A) by the method described later, the weight average molecular weight (Mw) was 1,600,000. In addition, 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 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 0.2 parts by mass of trimethylolpropane-modified xylylene diisocyanate (trade name “Takenate D110N” manufactured by Mitsui Chemicals Co., Ltd.) as a crosslinking agent (B) and 0.2 parts by mass of 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Industry, trade name "KBM403") as an epoxy group-containing silane coupling agent (C1), and 3- as a mercapto group-containing silane coupling agent (C2) 0.2 parts by mass of a cocondensate of mercaptopropyltrimethoxysilane and methyltriethoxysilane (manufactured by Shin-Etsu Chemical Industry, trade name "X-41-1810", mercapto equivalent: 450 g/mol), and an antistatic agent (D ) as a mixture of 2.0 parts by mass of N-octyl-4-methylpyridinium hexafluorophosphate (ionic compound solid at room temperature), sufficiently stirred, and diluted with ethyl acetate to obtain a coating solution of an adhesive composition. In addition, in this Example, low molecular weight components other than the above were not blended.

Here, Table 1 shows each formulation (value in terms of solid content) of the adhesive composition when the (meth)acrylic acid ester copolymer (A) is 100 parts by mass (value in terms of solid content). In addition, the details of the abbreviation etc. described in Table 1 are as follows.

[(meth)acrylic acid ester copolymer]

BA: n-butyl acrylate

IBXA: isobornyl acrylate

PhEA: 2-phenylethyl acrylate

HEA: 2-hydroxyethyl acrylate

CHA: cyclohexyl acrylate

MA: methyl acrylate

[Isocyanate-based crosslinking agent]

XDI: Trimethylolpropane-modified xylylene diisocyanate (manufactured by Mitsui Chemicals, trade name "Takenate D110N")

TDI: Trimethylolpropane-modified tolylene diisocyanate (manufactured by Nippon Polyurethane Industry, trade name "Colonate L")

[Antistatic agent]

Pry+PF6- (1): N-octyl-4-methylpyridinium hexafluorophosphate (ionic compound that is solid at room temperature)

Pry+PF6- (2): N-butyl-4-methylpyridinium hexafluorophosphate (ionic compound that is solid at room temperature)

Pry+PF6- (3): 1-butylpyridinium hexafluorophosphate (ionic compound solid at room temperature; manufactured by Tokyo Chemical Industry Co., Ltd.)

[Low Molecular Weight Ingredients]

Transstilbene: Transstilbene (manufactured by Tokyo Kasei Industrial Co., Ltd.)

Benzyl benzoate: Benzyl benzoate (manufactured by Wako Pure Chemical Industries, Ltd.)

Acrylic polymer (1): Acrylic acid ester copolymer having a weight average molecular weight (Mw) of 10,000 obtained by copolymerizing 70 parts by mass of n-butyl acrylate and 30 parts by mass of 2-phenylethyl acrylate.

Acrylic polymer (2): Acrylic polymer with a weight average molecular weight (Mw) of 3000 (trade name "ARUFON UP-1000" manufactured by Toa Synthetic Industries Co., Ltd.)

(3) Production of optical film with pressure-sensitive adhesive layer

The coating solution of the obtained adhesive composition was applied with a knife coater to the release treated surface of a release sheet (SP-PET3811, manufactured by Lintec, thickness: 38 μm) in which one side of a polyethylene terephthalate film was subjected to release treatment with a silicone release agent, It heat-processed at 90 degreeC for 1 minute, and the coating film of the adhesive composition was formed.

Subsequently, the composite polarizing plate obtained above is bonded to the coating film so that the surface of the first acrylic resin layer in the first retardation plate and the exposed surface of the coating film are in contact, and 7 at 23 ° C. and 50% RH By curing for one day, the optical film with an adhesive layer in which the adhesive layer was formed on the composite polarizing plate was obtained. In addition, the thickness of the pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer) formed was 20 µm.

[Examples 2 to 24, Comparative Examples 1 to 4]

Type and ratio of each monomer constituting the (meth)acrylic acid ester copolymer (A), weight average molecular weight (Mw) of the (meth)acrylic acid ester copolymer (A), type and compounding amount of the crosslinking agent (B), silane coupling agent An optical film with an adhesive layer was prepared in the same manner as in Example 1, except that the amount of (C), the type of antistatic agent (D), and the type and amount of low molecular weight components were changed as shown in Table 1.

Here, the weight average molecular weight (Mw) mentioned above is a weight average molecular weight in terms of polystyrene measured using gel permeation chromatography (GPC) under the following conditions (GPC measurement).

<measurement conditions>

GPC measuring device: Tosoh Corporation, HLC-8020

・GPC column (passed in the following order): manufactured by Tosoh Corporation

TSK guard column HXL-H

TSK gel GMHXL (× 2)

TSK gel G2000HXL

・Measurement solvent: tetrahydrofuran

・Measurement temperature: 40 ℃

[Test Example 1] (Measurement of gel fraction)

In place of the optical film used in the production of the optical film with the pressure-sensitive adhesive layer in Examples and Comparative Examples, a release sheet (SP-PET3801, manufactured by Lintec, thickness: 38 μm) in which one side of a polyethylene terephthalate film was subjected to release treatment with a silicone-based release agent was used. Using this, a pressure-sensitive adhesive sheet was prepared. Specifically, the release sheet was laminated on the exposed coating film of the structure comprising the release sheet/coating film of the adhesive composition obtained in the manufacturing process of Examples or Comparative Examples so that the release treatment surface side was in contact with it, and at 23°C, 50 It was cured for 7 days under the condition of %RH. Thus, a pressure-sensitive adhesive sheet composed of a release sheet (SP-PET3801)/a pressure-sensitive adhesive layer (thickness: 20 µm)/a release sheet (SP-PET3811) was produced.

The resulting PSA sheet is cut to a size of 80 mm × 80 mm, the PSA 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 to obtain only the PSA. The mass of was calculated. Let the mass at this time be M1.

Next, the adhesive wrapped in the polyester mesh was immersed in ethyl acetate at room temperature (23°C) for 24 hours. After that, the adhesive was taken out and air-dried in an environment of a temperature of 23°C and a relative humidity of 50% for 24 hours, and further dried in an 80°C oven for 12 hours. After drying, the mass of the adhesive alone was calculated by weighing the mass with a precision balance and subtracting the mass of the mesh alone. Let the mass at this time be M2. Gel fraction (%) is represented by (M2/M1) x 100. A result is shown in Table 2.

[Test Example 2] (durability evaluation)

The optical films with the pressure-sensitive adhesive layer obtained in Examples and Comparative Examples were cut to prepare samples having a size of 150 mm × 200 mm. After peeling off the release sheet from this sample and attaching it to alkali-free glass (Eagle XG, manufactured by Corning Co., Ltd.) via the exposed pressure-sensitive adhesive layer, it was pressurized at 0.5 MPa and 50°C for 20 minutes in an autoclave manufactured by Kurihara Manufacturing Co., Ltd. .

After that, it was introduced under the following three durability conditions, and after 250 hours, the presence or absence of lifting or peeling was confirmed using a 10-fold loupe. The evaluation criteria are as follows. A result is shown in Table 2.

(double-circle): No lifting or peeling was observed.

○: Lifting or peeling with a size of 0.5 mm or less was confirmed.

△: Lifting or peeling with a size of more than 0.5 mm and less than 1.0 mm was confirmed.

x: Lifting or peeling with a size exceeding 1.0 mm was confirmed.

＜Durability conditions＞

Heat resistance: 85 ℃ dry

Moist heat: 60 ℃, relative humidity 90% RH

·H.S. : -35 ℃ ⇔ 70 ℃ heat shock test for 30 minutes each, 200 cycles

[Test Example 3] (Evaluation of warpage resistance)

Optical films with an adhesive layer obtained in Examples and Comparative Examples were cut to a length of 200 mm and a width of 150 mm. The release sheet was peeled off from the optical film with the pressure-sensitive adhesive layer, and the exposed pressure-sensitive adhesive layer was bonded to the central portion of 250 mm long, 175 mm wide, and 0.5 mm thick alkali-free glass (manufactured by Corning, trade name "Eagle-XG"), , this was taken as a sample. This sample was left to stand at 85°C in a dry atmosphere for 250 hours. After that, it was taken out in an environment of 25 ° C. and 50% RH, placed on a horizontal table with the polarizing plate side up, and the amount of warping (distance between the corner and the table) from the table at each corner (4 points) of the sample was measured, and each The deflection amount of the corner was summed. Based on the results, the warpage resistance was evaluated as follows. A result is shown in Table 2.

◎: The total amount of deflection is 10 mm or less

○: The total amount of deflection exceeds 10 mm and is 15 mm or less

△: The total amount of deflection exceeds 15 mm and is 20 mm or less

×: The total amount of deflection exceeds 20 mm

[Test Example 4] (Evaluation of heat resistance nonuniformity)

The optical film with the pressure-sensitive adhesive layer obtained in Examples and Comparative Examples was adjusted to a size of 200 mm x 150 mm using a cutting device (super cutter, PN1-600 manufactured by Ogino Manufacturing Co., Ltd.). After peeling off the release sheet and attaching it to alkali-free glass (Eagle XG, manufactured by Corning Co., Ltd.) via the exposed pressure-sensitive adhesive layer, it was pressurized at 0.5 MPa and 50°C for 20 minutes in an autoclave manufactured by Kurihara Works. In addition, the said bonding was performed so that the polarization axis might become a crossed nicol state (polarization axis: ∠45°, ∠135°) of the optical film with an adhesive layer on the front and back of the alkali-free glass. In this state, after leaving it for 250 hours in an 80°C dry environment, it was left for 2 hours in an environment of 23°C and 50% RH, and this was used as a sample to evaluate heat resistance nonuniformity by the method shown below. A result is shown in Table 2.

<Evaluation method>

The sample was installed on a flat illuminator (HF-SL-A312LC, manufactured by Dentsu Sangyo Co., Ltd., illuminance: 26,000 Lux, luminance: 10,000 cd), and photographed with a two-dimensional color luminance meter (CA-2000, manufactured by Konica Minolta), It was converted into a luminance distribution image by analysis software (manufactured by Konica Minolta, CA-S20w). The luminance distribution image of the obtained sample was evaluated based on the evaluation criteria shown in Fig. 4 and below.

◎: The luminance distribution is almost uniform

○: There is slight deformation in the luminance distribution of the 4 sides

△: There is a clear deformation in the luminance distribution on the 4 sides

x: The luminance distribution on the 4 sides is severely distorted.

[Test Example 5] (adhesion measurement-reworkability evaluation)

A sample having a width of 25 mm and a length of 100 mm was cut out from the optical film with a pressure-sensitive adhesive layer obtained in Examples and Comparative Examples, the release sheet was peeled off, and the exposed pressure-sensitive adhesive layer was passed through the alkali-free glass (Eagle XG, manufactured by Corning). After sticking, it was pressurized at 0.5 MPa and 50 degreeC for 20 minutes with the autoclave by the Kurihara Manufacturing Co., Ltd. product. Then, after leaving it to stand for 24 hours under conditions of 23 ° C. and 50% RH, using a tensile tester (manufactured by Orientec Co., Ltd., Tensilon), the adhesive strength (attachment 1 Adhesion after days; N/25 mm) was measured. Conditions other than those described here were measured based on JIS Z 0237:2009. A result is shown in Table 2.

Furthermore, after leaving it to stand for 14 days under the conditions of 23 degreeC and 50%RH, it carried out similarly to the above and measured the adhesive force (adhesive force after 14 days of sticking; N/25 mm). Separately, after leaving it to stand for 2 days under conditions of 50°C and 50% RH, the adhesive force (adhesive force after 2 days at 50°C; N/25 mm) was measured in the same manner as above. A result is shown in Table 2.

Based on the adhesive strength after 14 days of application, reworkability was evaluated according to the following criteria. A result is shown in Table 2.

◎: Adhesion after 14 days of application is 8.8 N/25 mm or less

○: The adhesive strength after 14 days of attachment is more than 8.8 N/25 mm and less than 10 N/25 mm

△: The adhesive force after 14 days of attachment is 10 N/25 mm or more and less than 20 N/25 mm

×: The adhesive strength after 14 days of sticking is 20 N/25 mm or more

[Test Example 6] (Measurement of surface resistivity of pressure-sensitive adhesive layer)

The optical films with pressure-sensitive adhesive layers obtained in Examples and Comparative Examples were cut to a size of 50 mm x 50 mm, and the obtained samples were allowed to stand for 24 hours at a temperature of 23°C and a humidity of 50% RH. After that, the release sheet was peeled off, and the surface resistivity (Ω/sq) was measured on the surface of the exposed pressure-sensitive adhesive layer according to JIS K6911 using a resistivity meter (Hirestar UP MCP-HT450 type manufactured by Mitsubishi Chemical Analytech Co., Ltd.) ) was measured. A result is shown in Table 2.

As can be seen from Table 2, while being excellent in durability, the optical film with an adhesive layer obtained in the example did not easily generate heat unevenness either. Moreover, the surface resistivity of the adhesive layer of the optical film with an adhesive layer obtained in the Example was low, and the bad influence with respect to a liquid crystal cell etc. was small. Moreover, the optical film with an adhesive layer obtained in Examples 1-22 did not bend easily also under high temperature. Further, the optical films with the pressure-sensitive adhesive layer obtained in Examples 1 to 20 and 22 to 24 were also excellent in reworkability.

The optical film with a pressure-sensitive adhesive layer according to the present invention is suitable for bonding a thin polarizing plate or composite polarizing plate and a liquid crystal cell together.

10A, 10B: Optical film with pressure-sensitive adhesive layer
1: adhesive layer
2A: polarizer
2B: composite polarizer
21: polarizer
22: first protective layer
23: second protective layer
24: first retardation plate
241: first acrylic resin layer
242: phase difference expression layer
243: second acrylic resin layer
25: second retardation plate
26: second adhesive layer
27: protective layer

Claims (13)

an optical film;
A pressure-sensitive adhesive layer laminated on at least one side of the optical film
As an optical film with an adhesive layer provided with,
A 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) and an aromatic ring-containing monomer (a2) as monomer units constituting the polymer;
Crosslinker (B)
contains, and also
The content of the low molecular weight component is 5% by mass or less,
The (meth)acrylic acid ester copolymer (A) is composed of an adhesive obtained from an adhesive composition containing 1 to 30% by mass of the aromatic ring-containing monomer (a2) as a monomer unit constituting the polymer. Layered optical film. According to claim 1,
The optical film with a pressure-sensitive adhesive layer characterized in that the outermost layer of the optical film in contact with the pressure-sensitive adhesive layer is formed of an acrylic resin layer formed through extrusion molding. According to claim 2,
The optical film with an adhesive layer, characterized in that the optical film includes at least a retardation plate having the acrylic resin layer and a retardation developing layer. According to claim 3,
The optical film with an adhesive layer, characterized in that the phase difference expression layer is made of a styrenic resin. According to claim 3,
The said retardation plate has a 2nd acrylic resin layer on the surface side opposite to the surface on the side of the said acrylic resin layer in the said retardation expression layer, The optical film with an adhesive layer characterized by the above-mentioned. According to claim 3,
The optical film with an adhesive layer, characterized in that a second retardation plate is further laminated on a surface side of the retardation plate opposite to the surface on the pressure-sensitive adhesive layer side. According to claim 6,
The optical film with an adhesive layer characterized in that the second retardation plate is made of cycloolefin-based resin. According to claim 6,
An optical film with an adhesive layer, characterized in that a polarizing plate is further laminated on a surface side of the second retardation plate opposite to the surface on the side of the retardation plate. According to claim 1,
The (meth) acrylic acid ester copolymer (A),
As a monomer unit constituting the polymer, a hydroxyl group-containing monomer (a3) is further contained,
An optical film with a pressure-sensitive adhesive layer characterized by having a hydroxyl value of 5 to 20 mgKOH/g. According to claim 1,
The said crosslinking agent (B) is an isocyanate type crosslinking agent, The optical film with an adhesive layer characterized by the above-mentioned. According to claim 1,
The said adhesive composition further contains a silane coupling agent (C), The optical film with an adhesive layer characterized by the above-mentioned. According to claim 1,
The said adhesive composition further contains an antistatic agent (D) The optical film with an adhesive layer characterized by the above-mentioned. According to claim 12,
The optical film with a pressure-sensitive adhesive layer, characterized in that the antistatic agent (D) is an ionic compound that is solid at room temperature and is composed of a nitrogen-containing heterocyclic cation and a halogenated phosphoric acid anion.

Images