JP6444793B2 - Adhesive, adhesive sheet and optical film with adhesive layer - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive, a pressure-sensitive adhesive sheet, and an optical film with a pressure-sensitive adhesive layer, and particularly relates to a pressure-sensitive adhesive suitable for use in an optical film such as a polarizing plate and a composite polarizing plate, a pressure-sensitive adhesive sheet, and an optical film with a pressure-sensitive adhesive layer. Is.

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

  As a touch panel in a mobile electronic device such as a smartphone or a tablet terminal that has been attracting attention recently, a projected capacitive type is often used. As a projected capacitive touch panel in such mobile electronic devices, for example, in order from the bottom, a liquid crystal display (LCD), an adhesive layer, a transparent conductive film (tin-doped indium oxide: ITO), a glass substrate, a transparent conductive film ( ITO) and a laminate of protective plates such as tempered glass have been proposed.

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

  As an optical pressure-sensitive adhesive, for example, the one shown in Patent Document 1 is known. This pressure-sensitive adhesive contains 0.2 to 20 parts by weight of a carboxyl group-containing monomer as a copolymer component with respect to 100 parts by weight of an alkyl (meth) acrylate having an alkyl group having 4 to 14 carbon atoms as a monomer unit. 0.02 to 2 parts by mass of a peroxide and 0.005 to 5 parts by mass of an epoxy crosslinking agent as a crosslinking agent with respect to 100 parts by mass of the (meth) acrylic polymer and (meth) acrylic polymer to be formed Containing.

JP 2009-242786 A

  However, the conventional pressure sensitive adhesives such as Patent Document 1 do not have sufficient durability, and may float or peel off under high temperature conditions or wet heat conditions. In addition, with the recent thinning of mobile electronic devices, optical films such as polarizing plates have also been thinned. However, thin film polarizing plates have a high shrinkage rate due to heat and the like, and conventional adhesives are not suitable for display panels. Warping will occur. In particular, in order to improve the durability of the pressure-sensitive adhesive, when a monomer having a high glass transition point (Tg) is copolymerized as a component of the (meth) acrylic polymer, a large shrinkage stress is caused under heat resistant conditions. As a result, warping of the display panel increases. Furthermore, there has been pointed out a problem that light leakage (so-called heat unevenness) occurs due to a shift of the optical axis of the optical film due to the stress at the time of thermal shrinkage of the optical film.

  The present invention has been made in view of such a situation, and provides a pressure-sensitive adhesive, a pressure-sensitive adhesive sheet, and an optical film with a pressure-sensitive adhesive layer that are excellent in durability, are less likely to warp a display panel, and hardly cause heat unevenness. With the goal.

  In order to achieve the above object, first, the present invention includes an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2), and a hydroxyl group-containing monomer (a3) as monomer units constituting the polymer. And a (meth) acrylic acid ester copolymer (A) having a hydroxyl value of 5 to 20 mg KOH / g, an acid value of 5 mg KOH / g or less, and a weight average molecular weight of 1.3 to 3 million, and an isocyanate. A pressure-sensitive adhesive obtained from a pressure-sensitive adhesive composition containing a system crosslinking agent (B) and having a gel fraction of 60 to 89% is provided (Invention 1).

  The pressure-sensitive adhesive according to the above invention (Invention 1) has excellent durability when used in a display panel, and floats or peels off even under high temperature conditions, wet heat conditions or heat shock conditions. It is suppressed. Moreover, since the said adhesive is excellent in stress relaxation property, the display panel using the said adhesive is hard to warp also on high temperature conditions, and also it is hard to produce a thermal nonuniformity.

  In the said invention (invention 1), it is preferable that the alicyclic structure in the said alicyclic structure containing monomer (a1) is a polycyclic alicyclic structure (invention 2).

  In the said invention (invention 1 and 2), it is preferable that the said adhesive composition further contains an epoxy-group-containing silane coupling agent (C1) (invention 3).

  In the said invention (invention 1-3), it is preferable that the said adhesive composition further contains a mercapto group containing silane coupling agent (C2) (invention 4).

  In the said invention (invention 1-4), it is preferable that the said adhesive composition further contains an antistatic agent (D) (invention 5).

  In the above invention (Invention 5), the antistatic agent (D) is preferably an ionic compound that is solid at room temperature and is composed of a nitrogen-containing heterocyclic cation and a halogenated phosphate anion (Invention). 6).

  In the said invention (invention 1-6), it is preferable that the said isocyanate type crosslinking agent (B) is a compound which has an aromatic ring (invention 7).

  2ndly this invention provides the adhesive sheet characterized by including the adhesive layer which consists of said adhesive (invention 1-7) (invention 8).

  Thirdly, the present invention includes an optical film, and an optical layer with an adhesive layer, comprising: an optical film; and an adhesive layer made of the adhesive (Invention 1 to 7) laminated on at least one surface of the optical film. A film is provided (Invention 9).

  According to the pressure-sensitive adhesive, pressure-sensitive adhesive sheet and pressure-sensitive adhesive layer-equipped optical film according to the present invention, the durability is excellent, the display panel is hardly warped, and further, heat unevenness is hardly generated.

It is sectional drawing of the optical film with an adhesive layer which concerns on one Embodiment of this invention. It is sectional drawing of the optical film with an adhesive layer which concerns on other embodiment of this invention. It is sectional drawing which shows the structural example of a phase difference plate. It is a figure (color) which shows the evaluation criteria of the heat-resistant unevenness test (visual observation) in an optical film with an adhesive layer.

Hereinafter, embodiments of the present invention will be described.
[Adhesive]
The pressure-sensitive adhesive according to this embodiment contains an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2), and a hydroxyl group-containing monomer (a3) as monomer units constituting the polymer, and has a hydroxyl value. (Meth) acrylic acid ester copolymer (A) having an acid value of 5 to 20 mg KOH / g, an acid value of 5 mg KOH / g or less, and a weight average molecular weight of 1.3 to 3 million, and an isocyanate-based crosslinking agent (B) Is a pressure-sensitive adhesive obtained from a pressure-sensitive adhesive composition (hereinafter sometimes referred to as “pressure-sensitive adhesive composition P”), and has a gel fraction of 60 to 89%. In this specification, (meth) acrylic acid ester means both acrylic acid ester and methacrylic acid ester. The same applies to other similar terms.

  The pressure-sensitive adhesive satisfying the above requirements is excellent in durability when used in a display panel, and is prevented from being lifted or peeled off even under high temperature conditions, moist heat conditions or heat shocks. Moreover, the display panel using the said adhesive is hard to warp also on high temperature conditions, and also it is hard to produce a thermal nonuniformity.

  When the hydroxyl value of the (meth) acrylic acid ester copolymer (A) is less than 5 mgKOH / g, there are too few crosslinking points, the cohesive force is lowered, and the resulting pressure-sensitive adhesive does not exhibit excellent durability. Moreover, when the hydroxyl value of the (meth) acrylic acid ester copolymer (A) exceeds 20 mgKOH / g, there are too many cross-linking points, the resulting pressure-sensitive adhesive becomes inflexible, and the stress relaxation properties are reduced. The display panel warps or heat unevenness occurs under high temperature conditions.

  From the above viewpoint, the lower limit of the hydroxyl value of the (meth) acrylic acid ester copolymer (A) is preferably 8 mgKOH / g or more, and particularly preferably 10 mgKOH / g or more. The upper limit of the hydroxyl value of the (meth) acrylic acid ester copolymer (A) is preferably 18 mgKOH / g or less, and particularly preferably 16 mgKOH / g or less.

  On the other hand, if the acid value of the (meth) acrylic acid ester copolymer (A) is 5 mgKOH / g or less, the sticking target of the pressure-sensitive adhesive is a transparent material such as a tin-doped indium oxide (ITO) that causes problems due to acid. Even in the case of a conductive film, a metal film, or the like, those problems due to acid can be suppressed. In particular, when the object to be pasted is a transparent conductive film, it is possible to suppress corrosion of the transparent conductive film or change of the resistance value of the transparent conductive film.

  From the above viewpoint, the upper limit of the acid value of the (meth) acrylic acid ester copolymer (A) is preferably 2 mgKOH / g or less, and particularly preferably 1 mgKOH / g or less. In addition, since the lower limit of the acid value of (meth) acrylic acid ester copolymer (A) is so preferable that it is small, it is especially preferable that it is 0 mgKOH / g.

  Here, the hydroxyl value and acid value in the present 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, The measured value is based on JIS K0070.

  When the weight average molecular weight of the (meth) acrylic acid ester copolymer (A) is less than 1.3 million, the durability of the pressure-sensitive adhesive according to this embodiment is deteriorated. Moreover, when the weight average molecular weight of the (meth) acrylic acid ester copolymer (A) exceeds 3 million, the stress relaxation property of the pressure-sensitive adhesive according to this embodiment is lowered, and the display panel is warped under high temperature conditions. Or heat unevenness occurs.

  From the above viewpoint, the lower limit of the weight average molecular weight of the (meth) acrylic acid ester copolymer (A) is preferably 1.5 million or more, and particularly preferably 1.6 million or more. The upper limit of the weight average molecular weight of the (meth) acrylic acid ester copolymer (A) is preferably 2.5 million or less, particularly preferably 1.9 million or less.

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

  When the gel fraction of the pressure-sensitive adhesive according to this embodiment is less than 60%, the durability of the pressure-sensitive adhesive deteriorates. In addition, when the gel fraction of the pressure-sensitive adhesive according to the present embodiment exceeds 89%, the stress relaxation property of the pressure-sensitive adhesive according to the present embodiment is lowered, and the display panel is warped or heat unevenness occurs under high temperature conditions. Occur.

  From the above viewpoint, the lower limit of the gel fraction of the pressure-sensitive adhesive according to this embodiment is preferably 65% or more, and particularly preferably 73% or more. Moreover, it is preferable that the upper limit of the gel fraction of the adhesive which concerns on this embodiment is 85% or less, and it is especially preferable that it is 78% or less. In addition, the measuring method of the gel fraction of an adhesive is as showing to the test example mentioned later.

(1) (Meth) acrylic acid ester copolymer (A)
The (meth) acrylic acid ester copolymer (A) in the present embodiment includes, as monomer units constituting the polymer, an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2), and a hydroxyl group-containing monomer. (A3) is contained. Among these monomers, the pressure-sensitive adhesive obtained by combining the alicyclic structure-containing monomer (a1) and the aromatic ring-containing monomer (a2) can have both appropriate cohesive force and stress relaxation properties. At the same time, since the adhesiveness to the optical film and the transparent conductive film is increased, when used for a display panel, it is possible to exhibit excellent durability, warpage suppression, and heat unevenness.

  The (meth) acrylic acid ester copolymer (A) includes, as monomer units constituting the polymer, the alicyclic structure-containing monomer (a1), the aromatic ring-containing monomer (a2), and the hydroxyl group-containing monomer (a3). In addition, it is preferable to contain (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group. Moreover, you may contain another monomer if desired.

  The (meth) acrylic acid ester copolymer (A) contains a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group as a monomer unit constituting the polymer. Can be expressed. Examples of the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylic acid n-. Butyl, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-decyl (meth) acrylate, (meth) acrylic acid Examples include n-dodecyl, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, and the like. Among these, from the viewpoint of further improving the adhesiveness, (meth) acrylic acid esters having 1 to 8 carbon atoms in the alkyl group are preferable, and (meth) acrylic acid n-butyl or (meth) acrylic acid 2-ethylhexyl is particularly preferable. . 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) contains 40 to 97.5 mass% of (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms as the monomer unit constituting the polymer. In particular, it is preferably contained in an amount of 55 to 94% by mass, more preferably 65 to 83% by mass. If it contains 40 mass% or more of (meth) acrylic-acid alkylester, suitable adhesiveness can be provided to a (meth) acrylic-ester copolymer (A). Further, by making the (meth) acrylic acid alkyl ester 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 alicyclic carbocyclic ring in the alicyclic structure-containing monomer (a1) may have a saturated structure or may have an unsaturated bond in part. The alicyclic structure may be a monocyclic alicyclic structure or a polycyclic alicyclic structure such as a bicyclic ring or a tricyclic ring. From the viewpoint of making the distance between the obtained (meth) acrylic acid ester copolymer (A) appropriate and imparting stress relaxation to the pressure-sensitive adhesive, the alicyclic structure is a polycyclic alicyclic structure ( A polycyclic structure). Furthermore, considering the compatibility between the (meth) acrylic acid ester copolymer (A) and other components, the polycyclic structure is particularly preferably bicyclic to tetracyclic. In addition, from the viewpoint of imparting stress relaxation properties as described above, the carbon number of the alicyclic structure (refers to the total number of carbon atoms of the portion forming the ring, and when multiple rings exist independently) , Which means the total number of carbon atoms) is usually preferably 5 or more, and particularly preferably 7 or more. On the other hand, the upper limit of the number of carbon atoms in the alicyclic structure is not particularly limited, but it is preferably 15 or less and particularly preferably 10 or less from the viewpoint of compatibility as described above.

  Examples of the alicyclic structure include a 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, basketn skeleton, Hausan skeleton, spiro skeleton, etc. are included, and among them, more excellent durability is exhibited. Those containing a dicyclopentadiene skeleton (carbon number of alicyclic structure: 10), adamantane skeleton (carbon number of alicyclic structure: 10) or isobornyl skeleton (carbon number of alicyclic structure: 7) are particularly preferable. Contains isobornyl skeleton Preference is.

  The alicyclic structure-containing monomer (a1) is preferably a (meth) acrylic acid ester monomer containing the skeleton, specifically, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, (Meth) acrylic acid adamantyl, (meth) acrylic acid isobornyl, (meth) acrylic acid dicyclopentenyl, (meth) acrylic acid dicyclopentenyloxyethyl, etc. are mentioned, among them, more excellent durability, ( Dicyclopentanyl (meth) 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) is an alicyclic monomer unit that constitutes the polymer from the viewpoint that the resulting pressure-sensitive adhesive exhibits excellent durability, warpage suppression, and heat unevenness. It is preferable to contain 1-20 mass% of structure containing monomers (a1). Furthermore, in addition to the above viewpoint, it is more preferable that the alicyclic structure-containing monomer (a1) is particularly preferably contained in an amount of 2 to 15% by mass from the viewpoint that the resulting pressure-sensitive adhesive exhibits excellent reworkability. % Content is particularly preferable.

  As the aromatic ring-containing monomer (a2), a (meth) acrylic acid ester having an aromatic ring is preferable. Examples of the aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, a biphenyl ring, and a fluorene ring, and 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, and phenoxyethyl (meth) acrylate. , Phenoxybutyl (meth) acrylate, ethoxylated o-phenylphenol acrylate, phenoxydiethylene glycol (meth) acrylate, ethylene oxide modified cresol (meth) acrylate, ethylene oxide (EO) modified nonylphenol (meth) acrylate, and the like. From the viewpoint of improving cohesive strength, 2-phenylethyl (meth) acrylate is preferred. These may be used alone or in combination of two or more.

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

  The (meth) acrylic acid ester copolymer (A) contains a hydroxyl group-containing monomer (a3) as a monomer unit constituting the polymer. The hydroxyl group is highly reactive with the isocyanate group of the isocyanate-based crosslinking agent (B), and the (meth) acrylic acid ester copolymer (A) is crosslinked by the isocyanate-based crosslinking agent (B) by their reaction. Due to this crosslinked structure, the resulting pressure-sensitive adhesive is excellent in durability.

  Examples of the hydroxyl group-containing monomer (a3) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate. , (Meth) acrylic acid hydroxyalkyl esters such as (meth) acrylic acid 3-hydroxybutyl, (meth) acrylic acid 4-hydroxybutyl, etc., among others, the reactivity with the isocyanate-based crosslinking agent (B) To 2-hydroxyethyl (meth) acrylate or 4-hydroxybutyl (meth) acrylate is preferred, and 2-hydroxyethyl (meth) acrylate is particularly preferred. These may be used alone or in combination of two or more.

  The (meth) acrylic acid ester copolymer (A) preferably contains 0.5 to 10% by mass of the hydroxyl group-containing monomer (a3) as a monomer unit constituting the polymer, particularly 1 to 5% by mass. It is preferable to contain, Furthermore, it is preferable to contain 2-4 mass%. When the content of the hydroxyl group-containing monomer (a3) is in the above range, the hydroxyl value of the (meth) acrylic acid ester copolymer (A) easily enters the above range, and has excellent durability and warpage suppression. In addition, the heat unevenness can be effectively exhibited.

  The (meth) acrylic acid ester copolymer (A) preferably does not contain a carboxyl group-containing monomer as a monomer unit constituting the polymer so that the acid value is in the above-described range. The content is preferably 0.5% by mass or less, and particularly preferably 0.1% by mass or less.

  The (meth) acrylic acid ester copolymer (A) may contain a monomer other than the above-described monomers as a monomer unit constituting the polymer. The other monomer includes a functional group having reactivity with the isocyanate-based crosslinking agent (B) in order not to hinder the reaction between the hydroxyl group of the hydroxyl group-containing monomer (a3) and the isocyanate-based crosslinking agent (B). No monomer is preferred.

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

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

  Here, in the adhesive composition P, the (meth) acrylic acid ester copolymer (A) may be used alone or in combination of two or more. The adhesive composition P further includes a (meth) acrylic acid ester polymer that does not contain the alicyclic structure-containing monomer (a1), aromatic ring-containing monomer (a2), or hydroxyl group-containing monomer (a3) as a constituent monomer unit. You may contain.

(2) Isocyanate-based crosslinking agent (B)
The isocyanate-based crosslinking agent (B) has an advantage of excellent reactivity with the hydroxyl group (derived from the hydroxyl group-containing monomer (a3)) of the (meth) acrylic acid ester copolymer (A).

  The isocyanate-based crosslinking agent (B) 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, alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate, etc. In addition to these biuret bodies, isocyanurate bodies, and adduct bodies that are reaction products with low molecular active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylol propane, castor oil, etc. And may be referred to as “denatured”). Among these, from the viewpoint of durability of the obtained pressure-sensitive adhesive, a compound having an aromatic ring, that is, an aromatic polyisocyanate or a modified product thereof is preferable, and an organic group (for example, an alkylene chain is preferably included in the aromatic ring, 1 to 4 alkylene chains are particularly preferred.) Polyisocyanates having an isocyanate group bonded via each other or a modified product thereof are 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 (B) can be used individually by 1 type or in combination of 2 or more types.

  It is preferable that content of the isocyanate type crosslinking agent (B) in the adhesive composition P is 0.01-10 mass parts with respect to 100 mass parts of (meth) acrylic acid ester copolymers (A). In particular, it is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 0.4 parts by mass. When the content of the isocyanate-based crosslinking agent (B) is in the above range, the pressure-sensitive adhesive is easy to enter the above-described range, and a pressure-sensitive adhesive excellent in durability, warpage suppression and heat resistance unevenness is obtained. It becomes easy.

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

  The epoxy group-containing silane coupling agent (C1) is an organosilicon compound having at least one epoxy group (an organic group containing an epoxy group) and at least one alkoxysilyl group in the molecule, Those having good compatibility and having light transmission properties, for example, substantially transparent materials are preferred.

  Specific examples of the epoxy group-containing silane coupling agent (C1) include 3-glycidoxypropyltrialkoxysilane such as 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane, and 3-glycidyl. 3-glycidoxypropylalkyldialkoxysilanes such as sidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, methyltri (glycidyl) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane 2- (3,4-epoxycyclohexyl) ethyltrialkoxysilane such as 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane. Among these, 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 (an organic group containing a mercapto group) and at least one alkoxysilyl group in the molecule, Those having good compatibility and having light transmission properties, for example, substantially transparent materials are preferred.

  Specific examples of mercapto group-containing silane coupling agents (C2) include mercapto group-containing low molecular weight silane couplings such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane. Agents: mercapto group-containing silane compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane, methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyl Examples include mercapto group-containing oligomer type silane coupling agents such as co-condensates with alkyl group-containing silane compounds such as trimethoxysilane. Among these, 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. 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 epoxy group-containing silane coupling agent (C1) and the mercapto group-containing silane coupling agent (C2), for example, an acryloyl-based silane coupling agent, Hydroxyl silane coupling agents, carboxyl group silane coupling agents, amino group silane coupling agents, amide group silane coupling agents, isocyanate group silane coupling agents, and the like may be used in combination.

  The total content of the silane coupling agent (C) in the adhesive composition P is 0.01 to 5 parts by mass with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer (A). Particularly preferred is 0.1 to 2 parts by mass, and further preferred is 0.2 to 1 part by mass.

  Moreover, content of the epoxy group containing silane coupling agent (C1) in the adhesive composition P is 0.005-2.5 with respect to 100 mass parts of (meth) acrylic acid ester copolymers (A). The amount is preferably part by mass, particularly preferably 0.05 to 1 part by mass, and further preferably 0.1 to 0.5 part by mass. On the other hand, the content of the mercapto group-containing silane coupling agent (C2) in the adhesive composition P is 0.005 to 2.5 with respect to 100 parts by mass of the (meth) acrylic acid ester copolymer (A). The amount is preferably part by mass, particularly preferably 0.05 to 1 part by mass, and further preferably 0.1 to 0.5 part by mass.

(4) Antistatic agent (D)
The pressure-sensitive adhesive composition P preferably further contains an antistatic agent (D). Release films laminated on the adhesive layer or optical films such as polarizing plates and composite polarizing plates are usually made of plastic materials, so they have high electrical insulation properties, and static electricity is generated when the release sheets are peeled off. Easy to do. If a polarizing plate, a composite polarizing plate, or the like is bonded to a liquid crystal cell with the generated static electricity remaining, the orientation of liquid crystal molecules may be disturbed. Causes problems such as sucking. Therefore, when the pressure-sensitive adhesive composition P contains the antistatic agent (D), the resulting pressure-sensitive adhesive (pressure-sensitive adhesive layer) exhibits antistatic properties, and the above problems can be solved.

  The antistatic agent (D) is not particularly limited as long as it can impart antistatic properties to the resulting pressure-sensitive adhesive, and examples thereof include ionic compounds and nonionic compounds, among which ionic compounds are preferred. . 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 easily exhibiting stable antistatic properties even when exposed to durability conditions. . Here, the ionic compound in this specification refers to a compound in which a cation and an anion are combined mainly by electrostatic attraction.

  As the ionic compound, a nitrogen-containing onium salt, a sulfur-containing onium salt, a phosphorus-containing onium salt, an alkali metal salt and an alkaline earth metal salt are preferable. From the viewpoint of excellent durability of the obtained adhesive, a nitrogen-containing onium salt is particularly preferable. preferable. The nitrogen-containing onium salt is preferably an ionic compound composed of a nitrogen-containing heterocyclic cation and its counter anion, and is particularly an ionic compound composed of a nitrogen-containing heterocyclic cation and a halogenated phosphate anion. It is preferably an ionic compound that is solid at room temperature and is composed of a nitrogen-containing heterocyclic cation and a halogenated phosphate anion. According to an ionic compound that is solid at room temperature and is composed of a nitrogen-containing heterocyclic cation and a halogenated phosphate anion, it is possible to achieve both antistatic properties and durability.

  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. Moreover, as halogen of the halogenated phosphate anion, fluorine, chlorine, bromine and the like are preferable, and fluorine is particularly preferable.

  Specific examples of the antistatic agent (D) include N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methylpyridinium hexafluorophosphate, N-octylpyridinium hexafluorophosphate, and N-octyl-4. -Methylpyridinium hexafluorophosphate, N-dodecylpyridinium hexafluorophosphate, N-tetradecylpyridinium hexafluorophosphate, N-hexadecylpyridinium hexafluorophosphate, N-dodecyl-4-methylpyridinium hexafluorophosphate, N-tetradecyl-4 -Methylpyridinium hexafluorophosphate, N-hexadecyl-4-methylpyridinium hexafluorophosphate and the like. Among these, N-butyl-4-methylpyridinium hexafluorophosphate, N-hexyl-4-methylpyridinium hexafluorophosphate, and N- from the viewpoint of compatibility with the (meth) acrylic acid ester copolymer (A). Octyl-4-methylpyridinium hexafluorophosphate is preferred. The above antistatic agent (D) may be used individually by 1 type, and may be used in combination of 2 or more type.

  Content of the antistatic agent (D) in the adhesive composition which concerns on this embodiment is 0.1-15 mass parts with respect to 100 mass parts of (meth) acrylic acid ester copolymers (A). In particular, the amount is preferably 0.5 to 10 parts by mass, and more preferably 1 to 5 parts by mass. When the content of the antistatic agent (D) is within the above range, the antistatic property can be exhibited effectively, and the deterioration of physical properties such as optical properties and durability can be prevented.

(5) Various additives For the adhesive composition P, if desired, various additives usually used for acrylic adhesives, such as dispersants (for example, alkylene glycol dialkyl ethers), tackifiers, and antioxidants. An agent, an ultraviolet absorber, a light stabilizer, a softener, a filler, a refractive index adjusting agent, and the like can be added. The pressure-sensitive adhesive composition P represents a mixture of various components that remain in the pressure-sensitive adhesive layer or in a reacted state, and is a component that is removed in a drying step or the like, for example, polymerization described later. Solvents and dilution solvents are not included in the adhesive composition P.

[Method for producing adhesive composition]
The pressure-sensitive adhesive composition P was produced by producing a (meth) acrylic acid ester copolymer (A), the obtained (meth) acrylic acid ester copolymer (A), an isocyanate-based crosslinking agent (B), and a desired Can be produced by mixing a silane coupling agent (C), an antistatic agent (D), an additive and the like.

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

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

  Examples of organic peroxides include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, and di (2-ethoxyethyl) peroxy. Examples include dicarbonate, t-butyl peroxyneodecanoate, t-butyl peroxybivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide and the like.

  In addition, in the said superposition | polymerization process, the weight average molecular weight of the polymer obtained can be adjusted by mix | blending chain transfer agents, such as 2-mercaptoethanol.

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

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

  The concentration / viscosity of the coating solution thus prepared is not particularly limited as long as it can be coated, and can be appropriately selected depending on the situation. For example, it dilutes so that the density | concentration of the adhesive composition P may be 10-40 mass%. In addition, when obtaining a coating solution, addition of a dilution solvent etc. is not a necessary condition, and if a viscosity etc. which can be coated with the adhesive composition P are not necessary, a dilution solvent does not need to be added. In this case, the adhesive composition P becomes a coating solution using the polymerization solvent of the (meth) acrylic acid ester copolymer (A) as a dilution solvent.

  The pressure-sensitive adhesive according to the present embodiment is obtained from the pressure-sensitive adhesive composition P described above. Specifically, the pressure-sensitive adhesive composition P is crosslinked. The pressure-sensitive adhesive composition P can be crosslinked by heat treatment. In addition, this heat processing can also serve as the drying process at the time of volatilizing the dilution solvent of the adhesive composition P, etc.

  When performing heat processing, it is preferable that heating temperature is 50-150 degreeC, and it is especially preferable that it is 70-120 degreeC. The heating time is preferably 30 seconds to 10 minutes, particularly preferably 50 seconds to 2 minutes. After the heat treatment, if necessary, a curing period of about 1 to 2 weeks may be provided at room temperature (for example, 23 ° C., 50% RH). When the curing period is necessary, after the curing period has elapsed, when the curing period is unnecessary, an adhesive layer having predetermined physical properties is formed after the heat treatment.

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

[Adhesive sheet]
The pressure-sensitive adhesive sheet according to this embodiment includes a pressure-sensitive adhesive layer made of the above-described pressure-sensitive adhesive. A release sheet may be laminated on one side or both sides of the pressure-sensitive adhesive layer. Further, a release sheet may be laminated on one surface of the pressure-sensitive adhesive layer, and a desired base material may be laminated on the other surface. In addition, when the base material is an optical film, in this specification, the said adhesive sheet will correspond to the optical film with an adhesive layer mentioned later.

  Although the thickness of an adhesive layer is suitably determined according to the intended purpose of an adhesive sheet, it is 5-100 micrometers normally, Preferably it is the range of 10-60 micrometers, for example, when using as an adhesive layer of an optical film. Is preferably 10 to 50 μm, more preferably 15 to 30 μm.

  As the release sheet, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, 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 film, fluororesin film, etc. Is used. These crosslinked films are also used. Furthermore, these laminated films may be sufficient.

  It is preferable that at least one surface of the release sheet (particularly the release surface in contact with the pressure-sensitive adhesive layer) is subjected to a release treatment. Examples of the release agent used for the release treatment include alkyd, silicone, fluorine, unsaturated polyester, polyolefin, and wax release agents. In addition, the release surface of the release sheet in this specification refers to a surface having peelability in the release sheet, and includes both a surface that has been subjected to a release treatment and a surface that exhibits peelability without being subjected to a release treatment. .

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

  Although there is no restriction | limiting in particular about the thickness of a peeling sheet, Usually, it is about 20-150 micrometers.

  There is no restriction | limiting in particular as a base material, All what is used as a base material sheet of a normal adhesive sheet can be used. For example, in addition to a desired optical member (optical film), woven or non-woven fabric using fibers such as rayon, acrylic, polyester, etc .; synthetic paper; paper such as fine paper, glassine paper, impregnated paper, coated paper; aluminum, Metal foils such as copper; foams such as urethane foam and polyethylene foam; polyester films such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, polyurethane films, polyethylene films, polypropylene films, cellulose films such as triacetyl cellulose, Polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, acrylic resin film, norbornene resin film , A plastic film such as a cycloolefin resin film; and the like of two or more kinds of those laminates. The plastic film may be uniaxially stretched or biaxially stretched.

  Although the thickness of a base material changes also with the kind, it is 5-500 micrometers normally, Preferably it is 10-300 micrometers, Most preferably, it is 20-150 micrometers.

  As an example of the manufacturing method of the adhesive sheet which concerns on this embodiment, after apply | coating the application | coating solution of the adhesive composition P to the peeling surface of a peeling sheet and performing a heat processing and forming a coating film, if desired, Another release sheet (so that the release surface is in contact with the coating film) or a substrate is laminated on the coating film. When the curing period is unnecessary, the coating film becomes an adhesive layer as it is, and when the curing period is necessary, the coating film becomes an adhesive layer after the curing period. The conditions for the heat treatment and curing are as described above.

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

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

[Optical film with adhesive layer]
The optical film with an adhesive layer according to the present embodiment includes an optical film and an adhesive layer laminated on at least one surface of the optical film. An adhesive layer is formed from the adhesive which concerns on this embodiment mentioned above, or consists of an adhesive layer of the adhesive sheet which concerns on this embodiment mentioned above. The thickness and physical properties of the pressure-sensitive adhesive layer are the same as those of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet described above.

  The optical film may be composed of a single layer or a plurality of layers. As an optical film, for example, a polarizer, a polarizing plate, a retardation plate, a polarizing plate with a retardation plate, a viewing angle compensation film, a brightness enhancement film, a contrast enhancement film, a liquid crystal polymer film, a diffusion film, a half Examples thereof include a transflective film and a laminate thereof. Among these, from the viewpoint that the polarizer easily contracts, has a large dimensional change, and requires durability, the optical film including the polarizer is suitable as the optical film of the optical film with the pressure-sensitive adhesive layer according to the present embodiment. In particular, the thin polarizing plate with the protective layer being thinned, and the composite polarizing plate using the polarizing plate have a weak ability to suppress the shrinkage of the polarizer with the protective layer, and thus are easily contracted by heat, etc. It is optimal as an optical film of the optical film with an adhesive layer according to the present embodiment.

  Here, the surface in contact with the pressure-sensitive adhesive layer in the optical film may be composed of an acrylic resin. Moreover, the outermost layer in contact with the pressure-sensitive adhesive layer in the optical film may be composed of an acrylic resin layer formed through extrusion molding. Such an acrylic resin and a conventionally known pressure-sensitive adhesive layer have low adhesion and low durability, but according to the pressure-sensitive adhesive layer according to the present embodiment, the adhesive force to the acrylic resin is high, and Excellent stress relaxation. Therefore, it is excellent in durability even under high temperature conditions, moist heat conditions, heat shocks, and the like. The “acrylic resin layer formed through extrusion molding” includes an acrylic resin layer obtained by stretching after extrusion molding.

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

  The pressure-sensitive adhesive layer 1 is formed from the pressure-sensitive adhesive according to this embodiment 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 (the upper surface in FIG. 1), and the other surface of the polarizer 21 (FIG. 1 is provided with a second protective layer 23 laminated on the lower surface). Although not shown, an adhesive layer may be interposed between the polarizer 21 and the first protective layer 22 and / or between the polarizer 21 and the second protective layer 23.

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

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

  The degree of saponification of the polyvinyl alcohol 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 or polyvinyl acetal modified with aldehydes may be used. The degree of polymerization of the polyvinyl alcohol resin is usually 1,000 to 10,000, preferably 1,500 to 5,000.

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

  Uniaxial stretching may be performed before dyeing with a dichroic dye, may be performed simultaneously with dyeing with a dichroic dye, or may be performed after dyeing with a dichroic dye. When uniaxial stretching is performed after dyeing with a dichroic dye, this uniaxial stretching may be performed before boric acid treatment or during boric acid treatment. Of course, it is also possible to perform uniaxial stretching in these plural stages. For uniaxial stretching, rolls having different peripheral speeds may be uniaxially stretched or uniaxially stretched using a hot roll. Moreover, the dry-type extending | stretching which extends | stretches in air | atmosphere may be sufficient, and the wet extending | stretching which extends | stretches in the state swollen with the solvent may be sufficient. The draw ratio is usually about 4 to 8 times.

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

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

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

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

(2) Protective layer The first protective layer 22 and the second protective layer 23 (hereinafter sometimes collectively referred to as "protective layers 22 and 23") are preferably made 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 is preferably at least one resin selected from the group consisting of polyester resins, polycarbonate resins, acrylic resins, amorphous polyolefin resins, and cellulose resins.

  The amorphous polyolefin resin used for the protective layers 22 and 23 is preferably a cycloolefin resin. Examples of cycloolefin resins include resins obtained by performing ring-opening metathesis polymerization using cyclopentadiene and olefins by Diels-Alder reaction or a derivative thereof as a monomer, followed by hydrogenation; dicyclopentadiene and Resins obtained by performing ring-opening metathesis polymerization from olefins or methacrylates with Diels-Alder reaction obtained by Diels-Alder reaction as a monomer, followed by hydrogenation; norbornene, tetracyclododecene and the like Resins obtained by conducting ring-opening metathesis copolymerization in the same manner using two or more selected from the above derivatives and other cyclic polyolefin monomers, followed by hydrogenation; norbornene, tetra Kurododesen or their derivatives, resins obtained by addition copolymerization of aromatic compounds and the like having a vinyl group. Examples of commercially available amorphous polyolefin resins include “Arton” from JSR Corporation, “ZEONEX” and “ZEONOR” from ZEON Corporation, “APO” and “APO” from Mitsui Chemicals, Inc. Appel ”. When the amorphous polyolefin-based resin is formed into a film, a known method such as a solvent casting method or a melt extrusion method is appropriately used for forming the film.

  The cellulose resin is a resin in which at least a part of hydroxyl groups in cellulose is acetate esterified, and a mixed ester in which part is acetated and partly esterified with another acid. Good. The cellulose resin is preferably a cellulose ester resin, and more preferably an acetyl cellulose resin. Specific examples of the acetyl cellulose resin include triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate. Commercially available films made of such acetylcellulose-based resins include, for example, “Fujitac TD80”, “Fujitac TD80UF” and “Fujitac TD80UZ” manufactured by Fuji Film Co., Ltd., and “KC8UX2M” manufactured by Konica Minolta Opto Co., Ltd. "," KC2UA "," KC8UY "and the like.

  A cellulose resin film provided with an optical compensation function can also be used. As such an optical compensation film, for example, a film in which a compound having a retardation adjusting function is contained in a cellulose resin, a film in which a compound having a retardation adjusting function is applied to the surface of the cellulose resin, a cellulose resin is uniaxial or biaxial. Examples thereof include a film obtained by stretching on a shaft. Examples of commercially available optical compensation films for cellulose resins include “Wide View Film WV BZ 438” and “Wide View Film WV EA” manufactured by Fujifilm Corporation, manufactured by Konica Minolta Opto Corporation. There are “KC4FR-1” and “KC4HR-1”.

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

  Here, the 1st protective layer 22 and the 2nd protective layer 23 may consist of a transparent resin film of the same kind, and may consist of a transparent resin film of a different kind.

  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, primer treatment, and anchor coating treatment on the bonding surface. Moreover, you may have various process layers, such as a hard-coat layer, an antireflection layer, an anti-glare layer, in the surface on the opposite side to the bonding surface to the polarizer 21 of the protective layers 22 and 23. FIG.

  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 more preferably 10 to 30 μm.

  Among the above, the first protective layer 22 is preferably made of a cellulose-based resin, more preferably made of a cellulose ester-based resin, particularly preferably made of an acetylcellulose-based resin, and further preferably made of triacetylcellulose. preferable.

  Among the above, the second protective layer 23 is preferably made of an amorphous polyolefin-based resin, particularly preferably the above-described cycloolefin-based resin. Even in this case, the pressure-sensitive adhesive layer 1 has a high adhesive force to the second protective layer 23. Therefore, the optical film 10A with the pressure-sensitive adhesive layer is durable even under high temperature conditions, wet heat conditions, heat shocks, and the like. Excellent.

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

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

  The aqueous adhesive may contain a crosslinking agent. As the crosslinking agent, an amine compound, an aldehyde compound, a methylol compound, an epoxy compound, an isocyanate compound, a polyvalent metal salt and the like are preferable, and an epoxy compound is particularly preferable. Examples of commercially available cross-linking agents include Glyoxal and “Smilease Resin 650 (30)” which is an aqueous solution of a water-soluble epoxy compound sold by Sumika Chemtex Co., Ltd.

  Another preferred adhesive is an adhesive made of an epoxy resin composition containing an epoxy resin that is cured by irradiation with active energy rays or heating. When the adhesive is used, the adhesive between the films is applied by irradiating active energy rays or heating the adhesive layer interposed between the films to cure the curable epoxy resin contained in the adhesive. Can be done. Curing of the epoxy resin by irradiation with active energy rays or heating is preferably performed by cationic polymerization of the epoxy resin. In this specification, an epoxy resin means a compound having two or more epoxy groups in the molecule.

  From the viewpoint of weather resistance, refractive index, cationic polymerizability, etc., the epoxy resin contained in the curable epoxy resin composition that is an adhesive is preferably an epoxy resin that does not contain an aromatic ring in the molecule. Examples of such epoxy resins include hydrogenated epoxy resins, alicyclic epoxy resins, aliphatic epoxy resins, and the like.

(4) Manufacturing method of polarizing plate The manufacturing method of the polarizing plate 2A can be performed by an ordinary method. Hereinafter, as an example, a manufacturing method when a water-based adhesive is used as the adhesive will be described.

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

  The film thickness of the adhesive layer can be arbitrarily set by the characteristic design of the polarizing plate 2A, but from the viewpoint of reducing the adhesive material cost, a smaller one is preferable, and the viewpoint of suppressing defects such as air bubbles and foreign matters at the time of bonding. From the viewpoint of adhesion and durability, it is preferable to carry out within the optimum range determined for each combination of the adherend and the adhesive. In general, the thickness is 0.005 to 10 μm, preferably 0.01 to 5 μm, more preferably 0.03 to 1 μm.

  In adhering the polarizer 21 and the protective layers 22 and 23, a corona discharge treatment, a plasma treatment, a flame treatment, and a primer treatment are performed on one or both of the bonding surfaces before forming an adhesive coating layer. An easy adhesion treatment such as an anchor 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 bonded to the polarizer 21. Paste it on the other side. Thereby, the polarizing plate 2A formed by laminating the first protective layer 22, the polarizer 21, and the second protective layer 23 is obtained.

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

(5) Manufacturing method of optical film with adhesive layer As an example of the manufacturing method of optical film 10A with an adhesive layer, a peeling sheet is laminated | stacked on both surfaces of an adhesive layer as an adhesive sheet which concerns on this embodiment mentioned above. An adhesive sheet is prepared, and one release sheet (light release type release sheet) is released. And the 2nd protective layer 23 of polarizing plate 2A is piled up on the exposed adhesive layer, and an adhesive sheet and polarizing plate 2A are crimped | bonded. Thereby, 10 A of said optical films with an adhesive layer (with a peeling sheet) are obtained.

  As another example of the manufacturing method of the optical film 10A with an adhesive layer, the solution (coating solution) containing the adhesive composition P mentioned above is apply | coated to the peeling surface of a peeling sheet, and it heat-processes and performs a coating film. After the formation, the second protective layer 23 of the polarizing plate 2A is overlaid on the coating film. When a curing period is required, a curing period is set, and when the curing period is unnecessary, the coating film becomes the pressure-sensitive adhesive layer 1 as it is. Thereby, 10 A of said optical films with an adhesive layer (with a peeling sheet) are obtained.

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

  The pressure-sensitive adhesive layer 1 is formed from the pressure-sensitive adhesive according to this embodiment described above.

  The composite polarizing plate 2B in this embodiment includes a first retardation plate 24 that contacts the adhesive layer 1 and a second position that is located on the opposite side of the first retardation plate 24 from the adhesive layer 1 side. The phase difference plate 25, the second pressure-sensitive adhesive layer 26 interposed between the first phase difference plate 24 and the second phase difference plate 25, and the second pressure-sensitive adhesive layer 26 side of the second phase difference plate 25 The polarizer 21 is laminated on the opposite side of the polarizer 21, and the protective layer 27 is laminated on the opposite side of the polarizer 21 from the second retardation plate 25 side. Although not shown, an adhesive layer may be interposed between the polarizer 21 and the protective layer 27 and / or between the polarizer 21 and the second retardation plate 25. Such a composite polarizing plate 2B exhibits excellent viewing angle compensation performance.

(1) 1st phase difference plate The 1st phase difference plate 24 may consist of a single layer which expresses a phase difference, and may consist of a several layer containing a phase difference expression layer. As shown in FIG. 3, the first retardation plate 24 is preferably a retardation development layer 242 and a first layer laminated on one surface of the retardation development layer 242 (the lower surface in FIG. 3). 1 acrylic resin layer 241 and a second acrylic resin layer 243 laminated on the other surface (upper surface in FIG. 3) of the retardation developing layer 242. The phase difference expression layer 242 is preferably made of a styrene resin. Thus, it has the 1st phase plate 24 comprised including the 1st acrylic resin layer 241, the phase difference expression layer 242 which consists of a styrene resin, and the 2nd acrylic resin layer 243. The composite polarizing plate 2B is excellent in the viewing angle compensation performance of a liquid crystal display device, particularly an IPS (In-Place-Switching) mode liquid crystal display device. In addition, since the retardation development 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 retardation plate 24 has mechanical strength and resistance to resistance. Excellent chemical properties.

  In addition, the first retardation plate 24 is preferably provided with in-plane retardation by stretching. Thereby, the viewing angle compensation performance is further improved.

  The styrene resin constituting the retardation 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. It may be a coalescence. Styrene derivatives are compounds in which other groups are bonded to styrene, such as o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, o-ethylstyrene, p-ethyl. Alkyl styrene such as styrene, hydroxy styrene, tert-butoxy styrene, vinyl benzoic acid, o-chloro styrene, p-chloro styrene, such as hydroxyl group, alkoxy group, carboxyl group and halogen are introduced into the benzene nucleus of styrene. Substituted styrene and the like.

  As the styrenic resin, a terpolymer as disclosed in JP2003-50316A or JP2003-207640A can also be used.

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

  The thickness of the phase difference expression layer 242 is preferably 10 to 100 μm. When the thickness of the retardation developing layer 242 is 10 μm or more, a sufficient retardation value is exhibited by stretching. On the other hand, when the thickness of the retardation developing layer 242 is 100 μm or less, the impact strength is high, and the change in retardation due to external stress is small, so that when applied to a liquid crystal display device, heat unevenness or the like hardly occurs.

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

  Examples of the (meth) acrylic resin include a homopolymer of a methacrylic acid alkyl ester or an acrylic acid alkyl ester, a copolymer of a methacrylic acid alkyl ester and an acrylic acid alkyl ester, and the like. Examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, propyl methacrylate and the like. Examples of the alkyl acrylate ester include methyl acrylate, ethyl acrylate, and propyl acrylate. As such a (meth) acrylic resin, a commercially available (meth) acrylic resin can be used. Some (meth) acrylic resins include those called impact resistant (meth) acrylic resins, and high heat resistant (meth) acrylic resins having a glutaric anhydride structure or a lactone ring structure in the main chain. What is called is also included.

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

  The rubber particles may be made of a material having rubber elasticity uniformly in the form of particles, or may be a multilayer structure having at least one rubber elastic layer. As the acrylic rubber particles having a multilayer structure, particles having rubber elasticity as described above are used as cores, and the periphery thereof is covered with a hard alkyl methacrylate ester polymer, or a hard alkyl methacrylate ester polymer. The core is covered with an acrylic polymer having rubber elasticity as described above, and the hard core is covered with an acrylic polymer having rubber elasticity, and the surroundings are hard methacrylic acid. Examples thereof include those covered with an alkyl ester polymer.

  The average diameter of the rubber particles is preferably about 50 to 400 nm. The average diameter of the rubber particles can be measured by 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 100 parts by mass of the (meth) acrylic resin. The amount is preferably about 50 parts by mass.

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

  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, particularly 110 A (meth) acrylic resin composition at a temperature of 0 ° C. or lower is preferred. That is, it is preferable that the glass transition temperature (Tg) of the retardation developing layer 242 and the glass transition temperatures (Tg) of the first acrylic resin layer 241 and the second acrylic resin layer 243 do not overlap with each other. The layer 242 preferably has a glass transition temperature (Tg) higher than that of the first acrylic resin layer 241 and the second acrylic resin layer 243.

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

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

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

  In order to manufacture the first retardation plate 24, for example, a styrene resin and a (meth) acrylic resin composition containing rubber particles may be coextruded and then stretched. Stretching can be performed by longitudinal uniaxial stretching, tenter transverse uniaxial stretching, simultaneous biaxial stretching, sequential biaxial stretching, or the like, and may be performed so as to obtain a desired retardation value. In addition to the above method, single-layer films (a retardation developing layer 242, a first acrylic resin layer 241 and a second acrylic resin layer 243) are prepared and then thermally fused by heat lamination. And the laminate may be stretched.

  The total thickness of the first retardation plate 24 after stretching is preferably 5 to 100 μm, and 10 to 50 μm from the viewpoint of meeting the demand for thinning in mobile applications while maintaining sufficient performance. Is more 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, but in this case as well, the pressure-sensitive adhesive layer 1 is in contact with the first acrylic resin layer 241. Adhesive strength is high, and thus the optical film 10B with a pressure-sensitive adhesive layer is excellent in durability even under high temperature conditions, wet heat conditions, under heat shock, and the like.

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

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

  The cyclic olefin-based resin may or may not have a norbornane ring in its structural unit. Examples of the norbornene-based monomer that forms a cyclic olefin-based resin having no norbornane ring as a structural unit include, for example, those that become a 5-membered ring by ring opening, typically norbornene, dicyclopentadiene, 1- or 4- Examples thereof include methyl norbornene and 4-phenyl norbornene. When the cyclic olefin resin is a copolymer, the arrangement state of the molecules is not particularly limited, and may be a random copolymer, a block copolymer, or a graft copolymer. It may be a polymer.

  More specific examples of cyclic olefin resins include, for example, ring-opening polymers of norbornene monomers, ring-opening copolymers of norbornene monomers and other monomers, maleic acid addition and cyclopentadiene addition to them. Examples of the polymer-modified product, a polymer or copolymer obtained by hydrogenation of these, an addition polymer of a norbornene monomer, an addition copolymer of a norbornene monomer and another monomer, and the like. Examples of other monomers in the case of a copolymer include α-olefins, cycloalkenes, and non-conjugated dienes. Moreover, the cyclic olefin resin may be a copolymer using one or more of norbornene monomers and other alicyclic olefins.

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

  Commercially available products of cyclic olefin resins using norbornene-based monomers are trade names of “ZEONEX”, “ZEONOR” sold by Nippon Zeon Co., Ltd., and JSR Corp. “ Arton "etc. Commercially available products of these cyclic olefin-based resin films and stretched films thereof are also available, for example, “Zeonor Film” and JSR Co., Ltd., both of which are sold by Nippon Zeon Co., Ltd. There are “Arton Film” sold and “Essina” sold by Sekisui Chemical Co., Ltd.

  The second retardation plate 25 may be a film made of a mixed resin containing two or more types of olefin resins, or a film made of a mixed resin of an olefin resin and another thermoplastic resin. For example, the mixed resin containing two or more types of olefinic resins may include a mixture of the cyclic olefinic resin and the chain aliphatic olefinic resin as described above. When a mixed resin of an olefin resin and another thermoplastic resin is used, another thermoplastic resin is appropriately selected depending on the purpose. Specific examples include polyvinyl chloride resin, cellulose resin, polystyrene resin, acrylonitrile / butadiene / styrene copolymer resin, acrylonitrile / styrene copolymer resin, (meth) acrylic resin, polyvinyl acetate resin, polyvinyl chloride. Vinylidene resin, polyamide resin, polyacetal resin, polycarbonate resin, modified polyphenylene ether resin, polybutylene terephthalate resin, polyethylene terephthalate resin, polyphenylene sulfide resin, polysulfone resin, polyethersulfone resin, polyether Examples include ether ketone resins, polyarylate resins, liquid crystalline resins, polyamideimide resins, polyimide resins, polytetrafluoroethylene resins, and the like. A thermoplastic resin can be used individually by 1 type or in combination of 2 or more types. The thermoplastic resin may be used after any appropriate polymer modification. Examples of the polymer modification include copolymerization, crosslinking, molecular terminal modification, and stereoregularity imparting.

  When a mixed resin of an olefin resin and another thermoplastic resin is used, the content of the other thermoplastic resin is usually about 50% by mass or less and preferably about 40% by mass or less with respect to the entire resin. By setting the content of other thermoplastic resin within this range, the absolute value of the photoelastic coefficient is small, excellent wavelength dispersion characteristics are exhibited, and the retardation plate has excellent durability, mechanical strength and transparency. Can be obtained.

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

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

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

Second retardation plate 25 has an in-plane slow axis direction, and the refractive index in the in-plane fast axis direction and the thickness direction respectively n _x, and n _y and n _z, when the thickness of the film is d, the following Formula (1):
_{R e = (n x -n y} ) × d (1)
In-plane retardation value _{R e} in the definition is the wavelength 590nm is 30 to 150 nm, the following formula (2):
Nz factor _{= (n x -n z) /} (n x -n y) (2)
It is preferable that the Nz coefficient defined by the above has a refractive index anisotropy of more than 1 and less than 2.

  The second retardation plate 25 having the refractive index anisotropy as described above is obtained by longitudinal uniaxial stretching, tenter transverse uniaxial stretching, simultaneous biaxial stretching, sequential biaxial stretching, or the like of the film made of the olefin resin. In addition to adjusting the draw ratio and the draw speed appropriately, the desired refractive index difference can be determined by appropriately selecting various temperatures such as preheating temperature, drawing temperature, heat setting temperature, cooling temperature, and the like during drawing. You can get directionality.

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

(3) Second pressure-sensitive 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 may be used. Although an adhesive may be used, it is preferable to use an active energy ray-curable adhesive from the viewpoint of suppressing dimensional changes due to thermal contraction of the polarizing plate.

  The active energy ray-curable pressure-sensitive adhesive may be mainly composed of a polymer having active energy ray curability, a polymer not having active energy ray curability, an active energy ray curable polyfunctional monomer, and The main component may be a mixture with / or oligomer. Further, it may be a mixture of a polymer having active energy ray curability and a polymer not having active energy ray curability, or a polymer having active energy ray curability and an active energy ray curable polyfunctional monomer and / or Alternatively, it may be a mixture with an oligomer or a mixture of these three.

  Among these, a mixture of a polymer having no active energy ray curability and an active energy ray curable polyfunctional monomer and / or oligomer from the viewpoint of easily obtaining an adhesive that exhibits cohesion while maintaining tackiness. Are preferred, and in particular, those comprising a mixture of a polymer having no active energy ray curability and an active energy ray curable polyfunctional monomer as the main component are preferred.

  As a polymer which does not have active energy ray-curable property, (meth) acrylic acid ester polymer which does not have an active energy ray-curable group (hereinafter may be referred to as “(meth) acrylic acid ester polymer (X)”). Is preferred. The (meth) acrylic acid ester polymer (X) preferably contains a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group as a monomer constituting the polymer. Thereby, the obtained adhesive can express preferable adhesiveness. The (meth) acrylic acid ester polymer (X) is a monomer having a reactive functional group and a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group (reactive functional group-containing monomer). And a copolymer with other monomer used as desired. By including a reactive functional group-containing monomer as a monomer constituting the polymer (meth) acrylic acid ester polymer (X), it is possible to improve the adhesion with a glass surface such as a liquid crystal cell, Moreover, it can react with a crosslinking agent (Z) described later to form a crosslinked structure.

  Examples of the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylic acid n-. Butyl, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-decyl (meth) acrylate, (meth) acrylic acid Examples include n-dodecyl, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, and the like. Among these, from the viewpoint of further improving the adhesiveness, (meth) acrylic acid esters having 1 to 8 carbon atoms in the alkyl group are preferable, and n-butyl (meth) acrylate is particularly 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) may contain 50 to 99% by mass of a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms as a monomer unit constituting the polymer. It is preferable to contain 60-99 mass% especially, and it is preferable to contain 70-98 mass% further.

  As the reactive functional group-containing monomer, a monomer having a hydroxyl group in the molecule (hydroxyl group-containing monomer), a monomer having a carboxyl group in the molecule (carboxyl group-containing monomer), a monomer having an amino group in the molecule (amino group-containing) Monomer) and the like. One of these reactive functional group-containing monomers may be used alone, or two or more thereof may be used in combination.

  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 And (meth) acrylic acid hydroxyalkyl esters such as 3-hydroxybutyl acrylate and 4-hydroxybutyl (meth) acrylate.

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

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

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

  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, a polyfunctional acrylate monomer having a molecular weight of 1000 or less and excellent in compatibility with the (meth) acrylic acid ester polymer (X) and the like is preferable.

  Examples of polyfunctional acrylate monomers having a molecular weight of 1000 or less include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and polyethylene glycol diene. (Meth) acrylate, neopentyl glycol adipate di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified Bifunctional type such as di (meth) acrylate phosphate, di (acryloxyethyl) isocyanurate, allylated cyclohexyl di (meth) acrylate, etc .; trimethylolpropane tri (meth) acrylate , Dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, tris (acryloxyethyl) Trifunctional types such as isocyanurate and ε-caprolactone modified tris- (2- (meth) acryloxyethyl) isocyanurate; tetrafunctional types such as diglycerin tetra (meth) acrylate and pentaerythritol tetra (meth) acrylate; propionic acid 5-functional type such as modified dipentaerythritol penta (meth) acrylate; dipentaerythritol hexa (meth) acrylate, caprolactone modified dipentaerythritol hexa (meth) acrylate 6 functional types such as 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 5 to 30 parts by mass with respect to 100 parts by mass of the (meth) acrylic acid ester polymer (X). It is preferable that it is 10 to 20 parts by mass.

  The active energy ray-curable pressure-sensitive adhesive preferably contains a crosslinking agent (Z). When the active energy ray-curable pressure-sensitive adhesive contains a (meth) acrylate polymer (X) containing a reactive functional group-containing monomer as a monomer unit constituting the polymer, 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). Thereby, the structure by which (meth) acrylic acid ester polymer (X) was bridge | crosslinked with the crosslinking agent (Z) is formed, and the cohesion force of the adhesive obtained is improved.

  The crosslinking agent (Z) may be any one that reacts with the reactive functional group of the (meth) acrylic acid ester polymer (X). For example, an isocyanate crosslinking agent, an epoxy crosslinking agent, an amine crosslinking agent. , Melamine crosslinking agent, aziridine crosslinking agent, hydrazine crosslinking agent, aldehyde crosslinking agent, oxazoline crosslinking agent, metal alkoxide crosslinking agent, metal chelate crosslinking agent, metal salt crosslinking agent, ammonium salt crosslinking agent, etc. Is mentioned. As an isocyanate type crosslinking agent, the thing similar to the isocyanate type 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 0.01 to 10 parts by mass, particularly 0.05 to 5 parts by mass with respect to 100 parts by mass of the (meth) acrylic acid ester polymer (X). It is preferable that it is 0.1 to 1 part by mass.

  The active energy ray-curable pressure-sensitive adhesive may be optionally added with various additives such as a photopolymerization initiator, a silane coupling agent, a refractive index adjusting agent, an antistatic agent, a tackifier, an antioxidant, an ultraviolet absorber, and light. It may contain stabilizers, softeners, fillers and the like.

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

  Examples of the photopolymerization initiator include 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 phenyl ketone, 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′-diethylamino Benzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2 , 4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligo [2-hydroxy-2-methyl-1 [4- (1-methylvinyl) phenyl] propanone], 2,4 , 6-trimethylbenzoyl-diphenyl-phosphine oxide and the like. These may be used alone or in combination of two or more.

  The photopolymerization initiator is an amount in the range of 0.1 to 20 parts by mass, particularly 1 to 12 parts by mass with respect to 100 parts by mass of the active energy ray curable compound (Y) in the active energy ray curable adhesive. Is preferably used.

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

  Examples of such silane coupling agents include, in addition to the above-described epoxy group-containing silane coupling agent (C1) and mercapto group-containing silane coupling agent (C2), vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethyl. Polymerizable unsaturated group-containing silicon compounds such as methoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-amino Amino group-containing silicon compounds such as propylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, or at least one of these, methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane Emissions, such as condensation products of alkyl group-containing silicon compounds such as ethyl trimethoxysilane. These may be used individually by 1 type and may be used in combination of 2 or more type.

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

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

  The thickness of the 2nd adhesive layer 26 is about 1-50 micrometers normally, Preferably it is 1-20 micrometers, Most preferably, it is 2-7 micrometers. If the pressure-sensitive adhesive layer is too thin, the tackiness is lowered, and if it is too thick, problems such as the pressure-sensitive adhesive protruding easily occur.

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

(5) Protective layer The protective layer 27 is preferably made of a transparent resin film. As this protective layer 27, the thing similar to the 1st protective layer 22 in 2A of polarizing plates can be used.

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

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

  First, an adhesive coating film constituting the second adhesive layer 26 is formed on the release surface of the release sheet. Specifically, the adhesive coating liquid constituting the second adhesive layer 26 is applied to the release surface of the release sheet and dried.

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

  When the adhesive layer is formed as described above, the protective layer 27 is bonded to one surface of the polarizer 21 through the adhesive layer, and the second retardation plate 25 is attached to the other side of the polarizer 21. The laminated body (polarizing plate) which consists of the protective layer 27, the polarizer 21, and the 2nd phase difference plate 25 is obtained.

  Next, the coating film of the adhesive which comprises the 2nd adhesive layer 26 on the said peeling sheet is bonded to the surface at the side of the 2nd phase difference plate 25 of the obtained laminated body. And the active energy ray is irradiated through the said peeling sheet, the coating film of the said adhesive is hardened, and the said coating film is made into the 2nd adhesive layer 26. FIG.

  Here, active energy rays refer to those having energy quanta among electromagnetic waves or charged particle beams, and specific examples include ultraviolet rays and electron beams. Among active energy rays, ultraviolet rays that are easy to handle are particularly preferable.

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

  Finally, the release sheet is peeled from the second pressure-sensitive adhesive layer 26 formed as described above, and the second acrylic resin layer 243 in the first retardation plate 24 is exposed to the exposed second pressure-sensitive adhesive layer 26. Adhere the side surface. Thus, the composite polarizing plate 2B formed 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 20 to 300 μm, more preferably 30 to 150 μm, and particularly preferably 50 to 100 μm.

(8) Manufacturing method of optical film with adhesive layer As an example of the manufacturing method of optical film 10B with an adhesive layer, a peeling sheet is laminated | stacked on both surfaces of an adhesive layer as an adhesive sheet which concerns on this embodiment mentioned above. An adhesive sheet is prepared, and one release sheet (light release type release sheet) is released. And the 1st phase difference plate 24 of the composite polarizing plate 2B is piled up on the exposed adhesive layer, and an adhesive sheet and the composite polarizing plate 2B are pressure-bonded. Thereby, the said optical film 10B with an adhesive layer (with a peeling sheet) is obtained.

  As another example of the manufacturing method of the optical film 10B with an adhesive layer, after apply | coating the application | coating solution of the adhesive composition P mentioned above to the peeling surface of a peeling sheet and performing heat processing, forming a coating film, The first retardation plate 24 of the composite polarizing plate 2B is overlaid on the coating film. When a curing period is required, a curing period is set, and when the 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 peeling sheet) is obtained.

3. Physical properties of optical film with pressure-sensitive adhesive layer The pressure-sensitive adhesive strength of optical films 10A and 10B with pressure-sensitive adhesive layer according to this embodiment is preferably 0.5 to 20 N / 25 mm, particularly 1 It is preferable that it is-10N / 25mm. Thereby, the optical film with the pressure-sensitive adhesive layer is excellent in durability. Furthermore, it is preferable that the said adhesive force is 2-7 N / 25mm from a viewpoint which shall be excellent also about rework property. In addition, although the adhesive force here means the adhesive force measured by the 180 degree peeling method according to JIS Z0237: 2009, the measurement sample has a width of 25 mm and a length of 100 mm, and the measurement sample is attached. After being applied to the body by applying pressure at 0.5 MPa and 50 ° C. for 20 minutes, the sample was left for 24 hours under conditions of normal pressure, 23 ° C. and 50% RH, and then measured at a peeling rate of 300 mm / min. To do. When the adhesive strength is within the above range, it is possible to prevent floating or peeling when the adhesive is attached to the liquid crystal cell.

  Moreover, the optical films 10A and 10B with the pressure-sensitive adhesive layer according to the present embodiment are further adhered to the adherend after being left for 14 days under conditions of 23 ° C. and 50% RH (after 14 days of application). Is preferably 1 to 20 N / 25 mm, and particularly preferably 3 to 9 N / 25 mm. Thus, by suppressing the increase in adhesive strength over time, the optical films 10A and 10B with an adhesive layer according to the present embodiment are excellent in reworkability and can be easily reapplied even after being attached to a liquid crystal cell. be able to.

  Moreover, the optical films 10A and 10B with the pressure-sensitive adhesive layer according to this embodiment are further subjected to adhesive strength (50 ° C. 2) after being left on the adherend for 2 days under the conditions of 50 ° C. and 50% RH. The adhesive strength after the day is preferably 1 to 20 N / 25 mm from the viewpoint of durability, and more preferably 6 to 12 N / 25 mm from the viewpoint of reworkability.

The surface resistivity of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive layer-attached optical films 10A and 10B according to the present embodiment is preferably 1.0 × 10 ¹² Ω / sq or less, particularly 5.0 × 10 ¹¹ Ω / sq. Or less, more preferably 5.0 × 10 ¹⁰ Ω / sq or less. When the surface resistivity is not more than the above value, sufficient antistatic properties can be exhibited in the display panel. Such surface resistivity can be achieved when the adhesive composition P contains the antistatic agent (D) described above. In addition, the measurement of the surface resistivity of an adhesive layer shall be performed according to JISK6911, and is specifically as shown in the test example mentioned later. The lower limit value 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 and heat unevenness.

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

  Specifically, the pressure-sensitive adhesive layer of the optical films 10A and 10B with the pressure-sensitive adhesive layer (the pressure-sensitive adhesive layer exposed by peeling the release sheet when the release sheet is laminated) What is necessary is just to superimpose on a surface and to crimp. Thereby, the liquid crystal display device provided with the liquid crystal cell and the polarizing plate 2A and / or the composite polarizing plate 2B is obtained.

  Since the pressure-sensitive adhesive layer 1 of the optical films 10A and 10B with the pressure-sensitive adhesive layer according to this embodiment is excellent in durability, the pressure-sensitive adhesive is obtained even under high-temperature conditions, wet heat conditions, or heat shocks. Occurrence of floating or peeling at the interface of the layer 1 is suppressed. For example, when a glass plate to which the optical films 10A and 10B with adhesive layers are attached is placed under a high temperature condition of 85 ° C. or a wet heat condition of 60 ° C./90% RH for 250 hours, or a heat of −35 ° C. to 70 ° C. Even when a shock is applied (each 30 minutes, 200 cycles), the occurrence of floating or peeling is suppressed.

  Further, since the pressure-sensitive adhesive layer 1 of the optical films 10A and 10B with the pressure-sensitive adhesive layer according to the present embodiment is also excellent in stress relaxation properties, the obtained liquid crystal display device is not easily warped even under high temperature conditions, and further, heat unevenness. Is unlikely to occur. For example, even when a glass plate to which the optical films 10A and 10B with pressure-sensitive adhesive layers are attached is kept under high temperature conditions (for example, 80 to 85 ° C.) for 250 hours, it is difficult to warp and heat unevenness hardly occurs. In particular, even if the polarizing plate 2A or the composite polarizing plate 2B is a thin film, the liquid crystal display device hardly warps, and even if the liquid crystal cell has a high definition, heat unevenness hardly occurs.

  Here, a transparent conductive film may be present on the bonding surface of the liquid crystal cell with the pressure-sensitive adhesive layer 1, but in this case, the transparent conductive film is corroded or the resistance value of the transparent conductive film changes. It is suppressed.

  Examples of the transparent conductive film include metals such as platinum, gold, silver and copper, oxides such as tin oxide, indium oxide, cadmium oxide, zinc oxide and zinc dioxide, tin-doped indium oxide (ITO), and zinc oxide-doped oxide. Examples include composite oxides such as indium, fluorine-doped indium oxide, antimony-doped tin oxide, fluorine-doped tin oxide, and aluminum-doped zinc oxide, and non-oxidized compounds such as chalcogenide, lanthanum hexaboride, titanium nitride, and titanium carbide. It is done.

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

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples etc.

[Example 1]
1. Production of first optical film (polarizing plate) (1) Production of polarizer A polyvinyl alcohol film having a thickness of 75 μm made of polyvinyl alcohol having an average polymerization degree of about 2,400 and a saponification degree of 99.9 mol% or more, The film was uniaxially stretched about 5 times in a dry manner, and further immersed in pure water at 60 ° C. for 1 minute while maintaining the tension state. Then, it was immersed in an aqueous solution having a mass ratio of iodine / potassium iodide / water of 0.05 / 5/100 at 28 ° C. for 60 seconds. Subsequently, it was immersed in an aqueous solution having a mass ratio of potassium iodide / boric acid / water of 8.5 / 8.5 / 100 at 72 ° C. for 300 seconds. Next, after washing with pure water at 26 ° C. for 20 seconds, it was dried at 65 ° C. to obtain a polarizer in which iodine was adsorbed and oriented on polyvinyl alcohol.

(2) Preparation of polarizing plate 3 parts by mass of carboxyl group-modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name “KL-318”) is dissolved in 100 parts by mass of water, and the aqueous solution is a water-soluble epoxy resin. An epoxy adhesive was prepared by adding 1.5 parts by mass of a polyamide epoxy additive (made by Taoka Chemical Industry Co., Ltd., trade name “Smile Resin 650 (30)”, aqueous solution having a solid concentration of 30% by mass). . The said epoxy-type adhesive agent was apply | coated to one side of the polarizer obtained above.

  A 25 μm-thick triacetyl cellulose film (Konica Minolta Opto, Inc., trade name “KC2UA”) having a saponified surface as a first protective layer for the epoxy adhesive coating layer. ).

  Next, an epoxy adhesive is applied to the other surface of the polarizer in the same manner as described above, and a zero-position consisting of a cyclic olefin resin having a thickness of 23 μm is applied to the applied layer as a second protective layer. A phase difference film (manufactured by Zeon Corporation, trade name “ZEONOR”) was bonded. Thereafter, the first protective layer and the second protective layer were adhered to the polarizer by drying at 80 ° C. for 5 minutes. After bonding, the film is cured at 40 ° C. for 168 hours, and a first protective layer (layer thickness 25 μm), a polarizer (stretching ratio 5 times, layer thickness 15 μm) and a second protective layer (layer thickness 23 μm) are laminated. A polarizing plate (first optical film) having a total thickness of 63 μm was obtained.

2. Production of second optical film (composite polarizing plate) (1) Formation of coating film of active energy ray-curable pressure-sensitive adhesive Copolymerizing 95 parts by mass of n-butyl acrylate and 5 parts by mass of acrylic acid, (meth) Acrylic ester polymer (X) was prepared. When the molecular weight of this (meth) acrylic acid ester polymer (X) was measured by the method described later, it was a weight average molecular weight (Mw) of 2,000,000.

  Tris (acryloxyethyl) isocyanurate (manufactured by Toa Gosei Co., Ltd., trade name “100 parts by mass of (meth) acrylic acid ester polymer (X)) and active energy ray-curable compound (Y) (polyfunctional monomer)” Aronix M-315 ") 15 parts by mass, as a crosslinking agent (Z), 0.3 parts by mass of trimethylolpropane-modified tolylene diisocyanate (trade name“ Coronate L ”, manufactured by Nippon Polyurethane Industry Co., Ltd.), and a polymerization initiator , 1.5 parts by mass of a mixture of benzophenone and 1-hydroxycyclohexyl phenyl ketone (Ciba Specialty Chemicals, trade name “Irgacure 500”) mixed at a mass ratio of 1: 1, Glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBM4 3 ") were mixed with 0.2 parts by mass, sufficiently stirred, by diluting with ethyl acetate to obtain a coating solution of the active energy ray-curable pressure-sensitive adhesive.

  On the release treatment surface of the release sheet (SP-PET3811, thickness: 38 μm, manufactured by Lintec Co., Ltd.), one side of the polyethylene terephthalate film was release-treated with a silicone release agent. After coating with a knife coater, heat treatment was performed at 90 ° C. for 1 minute to form a coating film of an active energy ray-curable adhesive.

(2) Production of first retardation plate Methacrylic resin (manufactured by Sumitomo Chemical Co., Ltd.) containing about 20% by mass of acrylic rubber particles having an average particle diameter of 200 nm constituting the first acrylic resin layer. A product name “Technoloy S001”), a styrene-maleic anhydride copolymer resin (manufactured by Nova Chemical Co., Ltd., product name “Dylark D332”) constituting the phase difference layer, and a second acrylic resin layer. A methacrylic resin (manufactured by Sumitomo Chemical Co., Ltd., trade name “Technoloy S001”) containing about 20% by mass of acrylic rubber particles having an average particle size of 200 nm is co-extruded in that order in three layers and has a three-layer structure. A laminated film was obtained. The obtained laminated film is stretched, and a first retardation plate having an in-plane retardation value of 60 nm and a thickness of 25 μm (first acrylic resin layer / retardation expressing layer / second acrylic resin layer) Got.

(3) Preparation of composite polarizing plate First, the first optical film (polarizing plate) described above was prepared. The first protective layer and the second protective layer in the polarizing plate correspond to the protective layer and the second retardation plate in the composite polarizing plate produced here, respectively. That is, a polarizing plate was prepared by laminating a protective layer, a polarizer and a second retardation plate.

A coating film of the active energy ray-curable pressure-sensitive adhesive obtained in the step (1) is bonded to the surface of the polarizing plate on the second retardation plate side, and ultraviolet rays are passed through the release sheet under the following conditions. Irradiated to cure the pressure-sensitive adhesive coating film to form a second pressure-sensitive adhesive layer. Thereafter, the release sheet is peeled from the obtained second pressure-sensitive adhesive layer, and the second surface of the first phase difference plate obtained in the step (2) is exposed to the exposed surface of the second pressure-sensitive adhesive layer. The surface on the acrylic resin layer side was bonded. Thus, a composite polarizing plate (second 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. Got. Note that the thickness of the formed second pressure-sensitive adhesive layer was 5 μm.
<Ultraviolet irradiation conditions>
・ Use of high pressure mercury lamp ・ Illuminance 300mW / cm ² , Light quantity 300mJ / cm ²
・ Uses UVGraph-A1 made by Eye Graphics as UV illuminance / light meter

3. Manufacture of optical film with 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 acrylic acid 2 parts by mass of 2-hydroxyethyl were copolymerized to prepare a (meth) acrylic acid ester copolymer (A). When the molecular weight of this (meth) acrylic acid ester copolymer (A) was measured by the method mentioned later, it was weight average molecular weight (Mw) 1.6 million. In addition, from the said mixing | blending, the hydroxyl value of the said (meth) acrylic acid ester copolymer (A) is calculated to 14.49 mgKOH / g, and an acid value is calculated to 0 mgKOH / g.

(2) Preparation of adhesive composition 100 parts by mass of the (meth) acrylic acid ester copolymer (A) obtained in the above step (1), and trimethylolpropane-modified xylylene as an isocyanate crosslinking agent (B) 0.2 parts by mass of isocyanate (made by Mitsui Chemicals, trade name “Takenate D110N”) and 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., products) as an epoxy group-containing silane coupling agent (C1) Name “KBM403”) 0.2 parts by mass, and as a mercapto group-containing silane coupling agent (C2), a co-condensate of 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name) "X-411-1810", mercapto equivalent: 450 g / mol) 0.2 parts by mass, and antistatic agent (D), N- By mixing 2.0 parts by mass of octyl-4-methylpyridinium hexafluorophosphate (ionic compound that is solid at room temperature), stirring sufficiently, and diluting with ethyl acetate, a coating solution of the adhesive composition was prepared. Obtained.

Here, Table 1 shows each composition (solid content converted value) of the adhesive composition when the (meth) acrylic acid ester copolymer (A) is 100 parts by mass (solid content converted value). Details of the abbreviations and the like described in Table 1 are as follows.
[(Meth) acrylic acid ester copolymer]
BA: n-butyl acrylate MA: methyl acrylate HEA: 2-hydroxyethyl acrylate IBXA: isobornyl acrylate PhEA: 2-phenylethyl acrylate CHA: cyclohexyl acrylate
[Isocyanate-based crosslinking agent]
XDI: trimethylolpropane-modified xylylene diisocyanate (Mitsui Chemicals, trade name “Takenate D110N”)
[Antistatic agent]
Pry + PF6-: N-octyl-4-methylpyridinium hexafluorophosphate (ionic compound solid at room temperature)

(3) Production of optical film with pressure-sensitive adhesive layer A release sheet (SP-PET3811, manufactured by Lintec Corporation, thickness) obtained by subjecting one side of a polyethylene terephthalate film to a release treatment using a silicone-based release agent. : 38 μm) was coated with a knife coater and then heat-treated at 90 ° C. for 1 minute to form a coating film of the adhesive composition.

  Next, the polarizing plate as the first optical film obtained above was bonded to the coating film so that the surface of the second protective layer and the exposed surface of the coating film were in contact with each other. By curing for 7 days at 50% RH, a first optical film with an adhesive layer in which an adhesive layer was formed on the polarizing plate was obtained. The formed pressure-sensitive adhesive layer had a thickness of 20 μm.

  In addition, the composite polarizing plate as the second optical film obtained as described above, the surface of the first acrylic resin layer in the first retardation plate and the exposed surface of the coating film are in contact with each other. The second optical film with the pressure-sensitive adhesive layer in which the pressure-sensitive adhesive layer was formed on the composite polarizing plate was obtained by pasting with the coating film and curing at 23 ° C. and 50% RH for 7 days. The formed pressure-sensitive adhesive layer had a thickness of 20 μm.

[Examples 2 to 13, Comparative Examples 1 to 6]
Kind and ratio of each monomer constituting the (meth) acrylic acid ester copolymer (A), the weight average molecular weight of the (meth) acrylic acid ester copolymer (A), and the blending amount of the isocyanate crosslinking agent (B) The optical film with the pressure-sensitive adhesive layer was produced in the same manner as in Example 1 except for changing as shown in Table 1.

Here, the above-mentioned weight average molecular weight (Mw) is a polystyrene-reduced weight average molecular weight measured under the following conditions (GPC measurement) using gel permeation chromatography (GPC).
<Measurement conditions>
GPC measurement device: manufactured by Tosoh Corporation, HLC-8020
GPC column (passed in the following order): TSK guard column HXL-H manufactured by Tosoh Corporation
TSK gel GMHXL (× 2)
TSK gel G2000HXL
・ Measurement solvent: Tetrahydrofuran ・ Measurement temperature: 40 ° C.

  The following test examples were conducted on the second optical film with the pressure-sensitive adhesive layer produced in Examples and Comparative Examples.

[Test Example 1] (Measurement of gel fraction)
In place of the optical film used for the production of the optical film with the pressure-sensitive adhesive layer in Examples or Comparative Examples, a release sheet (SP-PET 3801, manufactured by Lintec Co., Ltd., thickness) on which one side of the polyethylene terephthalate film was treated with a silicone-based release agent. S: 38 μm) was used to prepare an adhesive sheet. Specifically, the release treatment surface side contacts the release sheet on the exposed coating film of the composition comprising the release sheet / adhesive composition coating film obtained in the production process of the examples or comparative examples. And then cured under conditions of 23 ° C. and 50% RH for 7 days. This produced the adhesive sheet which consists of a structure of a peeling sheet (SP-PET3801) / adhesive layer (thickness: 20 micrometers) / release sheet (SP-PET3811).

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

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

[Test Example 2] (Durability evaluation)
The optical film with an adhesive layer obtained in Examples and Comparative Examples was cut to prepare a sample having a size of 150 mm × 200 mm. The release sheet is peeled off from this sample and attached to an alkali-free glass (Corning Corp., Eagle XG) through the exposed adhesive layer, and then applied at 0.5 MPa and 50 ° C. for 20 minutes in an autoclave manufactured by Kurihara Seisakusho. Pressed.

Then, it put into the environment of the following three durability conditions, and the presence or absence of the float or peeling was confirmed using the 10 time loupe after 250 hours. The evaluation criteria are as follows. The results are shown in Table 2.
A: No lifting or peeling was confirmed.
○: Lifting or peeling of a size of 0.5 mm or less was confirmed.
(Triangle | delta): The float and peeling of a magnitude | size exceeding 0.5 mm and 1.0 mm or less were confirmed.
X: Floating and peeling of a size exceeding 1.0 mm were confirmed.
<Durability conditions>
・ Heat resistance: 85 ℃ dry
-Humid heat: 60 ° C, relative humidity 90% RH
・ H. S. : Heat shock test at -35 ° C to 70 ° C for 30 minutes each, 200 cycles

[Test Example 3] (Evaluation of warpage resistance)
The optical films with pressure-sensitive adhesive layers obtained in Examples and Comparative Examples were cut so as to be 200 mm long and 150 mm wide. The release sheet is peeled off from the optical film with the pressure-sensitive adhesive layer, and the exposed pressure-sensitive adhesive layer is placed in the center of 250 mm long, 175 mm wide, 0.5 mm thick non-alkali glass (trade name “Eagle-XG” manufactured by Corning). This was attached to the part and used as a sample. This sample was allowed to stand for 250 hours at 85 ° C. in a dry atmosphere. Thereafter, the sample is 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 warpage of each corner (four points) of the sample from the table (distance between the corner and the table). ) And the amount of warpage of each corner was summed. Based on the results, warpage resistance was evaluated as follows. The results are shown in Table 2.
◎: Total warpage amount is 10 mm or less ○: Total warpage amount is more than 10 mm, 15 mm or less △: Total warpage amount is more than 15 mm, 20 mm or less ×: Total warpage amount is more than 20 mm

[Test Example 4] (Evaluation of heat resistance unevenness)
The optical film with an adhesive layer obtained in Examples and Comparative Examples was adjusted to a size of 200 mm × 150 mm using a cutting device (Super cutter, PN1-600 manufactured by Hadano Seisakusho Co., Ltd.). The release sheet was peeled off and attached to alkali-free glass (Corning Corp., Eagle XG) through the exposed adhesive layer, and then pressurized at 0.5 MPa and 50 ° C. for 20 minutes in an autoclave manufactured by Kurihara Seisakusho. In addition, the said bonding was performed so that a polarizing axis might be in a crossed nicols state (polarizing axis: ∠45 °, ∠135 °) on the front and back of non-alkali glass. In this state, it was allowed to stand for 250 hours in an 80 ° C. dry environment, and then left for 2 hours in an environment of 23 ° C. and 50% RH. Using this as a sample, the heat resistance unevenness was evaluated by the following method. The results are shown in Table 2.

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

[Test Example 5] (Measurement of adhesive strength-reworkability evaluation)
Samples having a width of 25 mm and a length of 100 mm were cut out from the optical films with pressure-sensitive adhesive layers obtained in Examples and Comparative Examples, the release sheet was peeled off, and alkali-free glass (Corning Corp., Eagle) was exposed through the exposed pressure-sensitive adhesive layer. After being attached to XG), it was pressurized at 0.5 MPa and 50 ° C. for 20 minutes in an autoclave manufactured by Kurihara Seisakusho. Then, after leaving for 24 hours under conditions of 23 ° C. and 50% RH, using a tensile tester (Orientec Co., Ltd., Tensilon), the adhesive strength (adhesion) under the conditions of a peeling speed of 300 mm / min and a peeling angle of 180 degrees. The adhesive strength after 1 day; N / 25 mm) was measured. Conditions other than those described here were measured according to JIS Z 0237: 2009. The results are shown in Table 2.

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

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

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

  As can be seen from Table 2, the optical film with the pressure-sensitive adhesive layer obtained in the examples was excellent in durability, hardly warped even at high temperatures, and hardly caused heat unevenness. Moreover, the optical film with an adhesive layer obtained in the Example had a low surface resistivity of the adhesive layer, and had a small adverse effect on liquid crystal cells and the like. Furthermore, the optical film with an adhesive layer obtained in Examples 1 to 12 was excellent in reworkability.

  The pressure-sensitive adhesive, pressure-sensitive adhesive sheet and optical film with a pressure-sensitive adhesive layer according to the present invention are suitable for bonding a polarizing plate or a composite polarizing plate and a liquid crystal cell, particularly a liquid crystal cell having a transparent conductive film on the bonding surface. is there.

DESCRIPTION OF SYMBOLS 10A, 10B ... Optical film 1 with an adhesive layer ... Adhesive layer 2A ... Polarizing plate 2B ... Composite polarizing plate 21 ... Polarizer 22 ... 1st protective layer 23 ... 2nd protective layer 24 ... 1st phase difference plate DESCRIPTION OF SYMBOLS 241 ... 1st acrylic resin layer 242 ... Retardation expression layer 243 ... 2nd acrylic resin layer 25 ... 2nd phase difference plate 26 ... 2nd adhesive layer 27 ... Protective layer

Claims (9)

As a monomer unit constituting the polymer, an alicyclic structure-containing monomer (a1), an aromatic ring-containing monomer (a2), and a hydroxyl group-containing monomer (a3) are contained, and the hydroxyl value is 5 to 20 mgKOH / g, A (meth) acrylic acid ester copolymer (A) having a value of 5 mg KOH / g or less and a weight average molecular weight of 1.3 to 3 million;
A pressure-sensitive adhesive obtained from a pressure-sensitive adhesive composition containing an isocyanate-based crosslinking agent (B),
A pressure-sensitive adhesive having a gel fraction of 60 to 89%.   The pressure-sensitive adhesive according to claim 1, wherein the alicyclic structure in the alicyclic structure-containing monomer (a1) is a polycyclic alicyclic structure.   The pressure-sensitive adhesive according to claim 1 or 2, wherein the pressure-sensitive adhesive composition further contains an epoxy group-containing silane coupling agent (C1).   The pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive composition further contains a mercapto group-containing silane coupling agent (C2).   The pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive composition further contains an antistatic agent (D).   The pressure-sensitive adhesive according to claim 5, wherein 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 phosphate anion. .   The pressure-sensitive adhesive according to any one of claims 1 to 6, wherein the isocyanate-based crosslinking agent (B) is a compound having an aromatic ring.   A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive according to claim 1. An optical film;
An optical film with an adhesive layer, comprising: an adhesive layer made of the adhesive according to any one of claims 1 to 7, which is laminated on at least one surface of the optical film.

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