JP2017071770A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition which exhibits good durability when stuck as an adhesive layer to a surface of an optical member, an adhesive layer containing the same, and an adhesive layer-attached optical member including the adhesive layer.SOLUTION: The adhesive composition contains: 100 pts.wt. of a (meth)acrylic resin (A) in which the content of a constituent unit derived from a (meth)acrylic monomer having a hydroxyl group is 0.2 to 4 wt.% and the content of a constituent unit derived from a (meth)acrylic monomer having a carboxyl group is 0 to 4 wt.% and which has a glass transition temperature of -55°C or higher; and 0.1 to 1 pt.wt. of an isocyanate-based crosslinking agent (B) in which an isocyanate group is bonded to a carbon atom constituting an aliphatic skeleton. The adhesive layer contains the adhesive composition. The adhesive layer-attached optical member includes the adhesive layer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pressure-sensitive adhesive composition, and also relates to a pressure-sensitive adhesive layer containing the same and an optical member including the pressure-sensitive adhesive layer.

  A polarizing plate formed by laminating and bonding a protective film on one or both sides of a polarizer is an image display device such as a liquid crystal display device or an organic electroluminescence (organic EL) display device, particularly a mobile phone, a smart phone, or a tablet terminal in recent years. It is an optical member widely used in various mobile devices. An optical member such as a polarizing plate is often used by being bonded to another member (for example, an optical member such as a liquid crystal cell in a liquid crystal display device) via an adhesive layer [for example, Japanese Patent Application Laid-Open No. 2010-229321. Gazette (Patent Document 1)]. For this reason, for example, in many cases, a polarizing plate is marketed in the form of a polarizing plate with an adhesive layer in which an adhesive layer is previously provided on one surface thereof.

JP 2010-229321 A

  Durability is required for the pressure-sensitive adhesive composition used for the pressure-sensitive adhesive layer for bonding optical members. That is, the adhesive layer bonded to the optical member and incorporated in the image display device or the like may be placed in a high temperature or high temperature and high humidity environment, or may be placed in an environment where high and low temperatures are repeated. However, the pressure-sensitive adhesive layer is required to be able to suppress problems that may occur with changes in the dimensions of adjacent optical members even under these circumstances. Such defects include floating or peeling at the interface between the pressure-sensitive adhesive layer and the optical member adjacent thereto, and foaming of the pressure-sensitive adhesive layer.

  However, the conventional pressure-sensitive adhesive composition may have insufficient durability when bonded to an optical member as a pressure-sensitive adhesive layer, and the surface of the optical member for bonding the pressure-sensitive adhesive layer is a surface activity such as corona treatment. In particular, the durability may be insufficient when the surface is not easily activated even by the treatment.

  The present invention provides a pressure-sensitive adhesive composition having good durability when bonded to the surface as a pressure-sensitive adhesive layer, even if the surface of the optical member is a surface that is not easily activated even by surface activation treatment, It is an object of the present invention to provide a pressure-sensitive adhesive layer containing, and an optical member with a pressure-sensitive adhesive layer including the pressure-sensitive adhesive layer.

The present invention provides the following pressure-sensitive adhesive composition, pressure-sensitive adhesive layer, and optical member with a pressure-sensitive adhesive layer.
[1] The content of the structural unit derived from the (meth) acrylic monomer having a hydroxyl group is 0.2 to 4% by weight, and the content of the structural unit derived from the (meth) acrylic monomer having a carboxyl group 100 parts by weight of (meth) acrylic resin (A) having an amount of 0 to 4% by weight and a glass transition temperature of −55 ° C. or higher;
0.1 to 1 part by weight of an isocyanate-based crosslinking agent (B) in which an isocyanate group is bonded to a carbon atom constituting an aliphatic skeleton;
A pressure-sensitive adhesive composition comprising:

  [2] The pressure-sensitive adhesive composition according to [1], wherein the isocyanate group is bonded to a carbon atom constituting a methylene group.

  [3] The pressure-sensitive adhesive composition according to [1] or [2], wherein the content of the structural unit derived from the (meth) acrylic monomer having a hydroxyl group is 3.5% by weight or less.

  [4] The pressure-sensitive adhesive composition according to any one of [1] to [3], further containing an ionic compound (C).

  [5] The pressure-sensitive adhesive composition according to any one of [1] to [4], further containing a silane compound (D).

[6] A pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition according to any one of [1] to [5].
[7] An optical member with an adhesive layer comprising an optical member and the adhesive layer according to [6] laminated thereon.

  [8] The optical member with an adhesive layer according to [7], wherein the surface of the optical member on which the adhesive layer is laminated has a contact angle change rate of 40% or less when corona treatment is performed.

[9] The optical member includes a polarizer and a protective film laminated thereon,
The said surface is an optical member with an adhesive layer as described in [8] which is the surface of the said protective film.

  [10] The optical member with an adhesive layer according to [8] or [9], wherein the surface is a corona-treated surface.

  ADVANTAGE OF THE INVENTION According to this invention, an adhesive composition with favorable durability, an adhesive layer containing the same, and an optical member with an adhesive layer provided with the said adhesive layer can be provided.

It is a schematic sectional drawing which shows an example of the optical member with an adhesive layer which concerns on this invention. It is a schematic sectional drawing which shows another example of the optical member with an adhesive layer which concerns on this invention. It is a schematic sectional drawing which shows another example of the optical member with an adhesive layer which concerns on this invention. It is a schematic sectional drawing which shows another example of the optical member with an adhesive layer which concerns on this invention.

<Adhesive composition>
[1] (Meth) acrylic resin (A)
The (meth) acrylic resin (A) is a polymer containing a structural unit derived from a (meth) acrylic monomer having a hydroxyl group. Preferably, in addition to this structural unit, the following formula (I):

It is a polymer which contains as a main component the structural unit derived from the (meth) acrylic acid ester represented by these. In the present specification, “(meth) acryl” means acryl and / or methacryl, and “(meth)” such as (meth) acrylate has the same meaning.

In the above formula (I), R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkyl group having 1 to 14 carbon atoms which may be substituted with an alkoxy group having 1 to 10 carbon atoms, or 1 to 1 carbon atoms. It represents an aralkyl group having 7 to 21 carbon atoms which may be substituted with 10 alkoxy groups. R ² is preferably an alkyl group having 1 to 14 carbon atoms which may be substituted with an alkoxy group having 1 to 10 carbon atoms.

  Specific examples of the (meth) acrylic acid ester represented by the formula (I) include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and n-butyl (meth) acrylate. , (Meth) acrylic acid n-octyl, linear (meth) acrylic acid alkyl ester such as (meth) acrylic acid lauryl; (meth) acrylic acid isobutyl, (meth) acrylic acid 2-ethylhexyl, (meth) Branched (meth) acrylic acid alkyl esters such as isooctyl acrylate are included.

When R ² is an alkyl group substituted with an alkoxy group, i.e., specific examples of the (meth) acrylic acid ester represented by formula (I) when R ² is an alkoxyalkyl group, (meth) acrylic Acid 2-methoxyethyl, (meth) acrylic acid ethoxymethyl and the like. Specific examples of the (meth) acrylic acid ester represented by the formula (I) when R ² is an aralkyl group having 7 to 21 carbon atoms include benzyl (meth) acrylate and the like.

  The (meth) acrylic acid ester represented by the formula (I) may be used alone or in combination of two or more. Especially, it is preferable that (meth) acrylic acid ester contains n-butyl acrylate. The (meth) acrylic resin (A) preferably contains 50% by weight or more of a structural unit derived from n-butyl acrylate in all the structural units constituting the (meth) acrylic resin (A). Of course, in addition to n-butyl acrylate, other (meth) acrylic acid esters represented by the formula (I) may be used in combination.

  Content of the structural unit derived from the (meth) acrylic acid ester represented by the formula (I) is usually 60% by weight or more and less than 100% by weight in all the structural units constituting the (meth) acrylic resin (A). Yes, preferably 70 to 99.9% by weight, more preferably 80 to 99.6% by weight.

  The (meth) acrylic resin (A) contains a structural unit derived from a (meth) acrylic monomer having a hydroxyl group. Inclusion of this structural unit is advantageous for enhancing the adhesion between the pressure-sensitive adhesive layer and the optical member and the durability of the pressure-sensitive adhesive layer. A preferred example of the (meth) acrylic monomer having a hydroxyl group is a (meth) acrylic acid ester having a hydroxyl group. Specific examples of the (meth) acrylic acid ester having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, (meth) acrylic acid 2 -(2-hydroxyethoxy) ethyl, (meth) acrylic acid 2- or 3-chloro-2-hydroxypropyl, diethylene glycol mono (meth) acrylate and the like.

  Content of the structural unit derived from the (meth) acrylic monomer having a hydroxyl group is 4% by weight or less, preferably 3.5% by weight in all the structural units constituting the (meth) acrylic resin (A). % Or less, and more preferably 3% by weight or less. When the content of the structural unit derived from the (meth) acrylic monomer having a hydroxyl group exceeds 4% by weight, the durability of the pressure-sensitive adhesive layer, particularly heat resistance, is insufficient. On the other hand, the content of the structural unit derived from a (meth) acrylic monomer having a hydroxyl group is usually 0.2% by weight or more, preferably 0.5% by weight or more, more preferably 1.0% by weight. % Or more. When the content of the structural unit derived from the (meth) acrylic monomer having a hydroxyl group is less than 0.2% by weight, the adhesiveness between the pressure-sensitive adhesive layer and the optical member, the durability of the pressure-sensitive adhesive layer, etc. are insufficient. .

  The (meth) acrylic resin (A) can contain a structural unit derived from a monomer having a polar functional group other than the (meth) acrylic monomer having a hydroxyl group. The monomer having a polar functional group is preferably a (meth) acrylic monomer having a polar functional group. Examples of the polar functional group possessed by the monomer include a carboxyl group (free carboxyl group), an amino group, a heterocyclic group (for example, an epoxy group), and the like.

  Specific examples of the monomer having another polar functional group include monomers having a carboxyl group such as (meth) acrylic acid, methacrylic acid, β-carboxyethyl (meth) acrylate; acryloylmorpholine, vinylcaprolactam, N -Vinyl-2-pyrrolidone, vinylpyridine, tetrahydrofurfuryl (meth) acrylate, caprolactone-modified tetrahydrofurfuryl acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl (meth) acrylate, 2,5-dihydrofuran Monomers having a heterocyclic group such as: a monomer having an amino group different from a heterocyclic group such as aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and dimethylaminopropyl (meth) acrylate Including mass. As the monomer having another polar functional group, only one kind may be used alone, or two or more kinds may be used in combination.

  In addition to the (meth) acrylic monomer having a hydroxyl group, using a monomer having another polar functional group, in particular, a (meth) acrylic monomer having a carboxyl group, This is advantageous in improving the adhesion to the optical member and the durability (particularly heat resistance) of the pressure-sensitive adhesive layer.

  The content of the structural unit derived from a monomer having another polar functional group, preferably a (meth) acrylic monomer having a carboxyl group, is in all structural units constituting the (meth) acrylic resin (A). , 0% by weight or more, preferably 4% by weight or less. As described above, the (meth) acrylic resin (A) preferably contains a structural unit derived from a (meth) acrylic monomer having a carboxyl group, and the content thereof is (meth) acrylic resin ( In all the structural units constituting A), it is preferably 0.02% by weight or more, more preferably 0.05% by weight or more, and further preferably 0.1% by weight or more. When the content of the structural unit derived from the monomer having another polar functional group is less than 0.02% by weight, the effect of use is hardly recognized. On the other hand, the content of the structural unit derived from a monomer having another polar functional group, preferably a (meth) acrylic monomer having a carboxyl group, is the total constitution of the (meth) acrylic resin (A). In a unit, Preferably it is 4 weight% or less, More preferably, it is 3.5 weight% or less. When the content of the structural unit derived from a monomer having another polar functional group exceeds 4% by weight, durability of the pressure-sensitive adhesive layer, particularly heat resistance, tends to be insufficient. The structural unit derived from the monomer having all polar functional groups including the (meth) acrylic monomer having a hydroxyl group is usually 1 to 4 in all the structural units constituting the (meth) acrylic resin (A). 10% by weight, preferably 1.1-8% by weight.

  The (meth) acrylic resin (A) is a monomer having one olefinic double bond and at least one aromatic ring in the molecule (however, the monomer having the above formula (I) or the above polar functional group). A structural unit derived from (excluding those corresponding to a polymer) may be further included. Preferable examples include (meth) acrylic monomers having an aromatic ring. Such a (meth) acrylic monomer having an aromatic ring includes neopentyl glycol benzoate (meth) acrylate and the like, and in particular, the following formula (II):

A (meth) acrylic acid ester having an aryloxyalkyl group such as a phenoxyethyl group-containing (meth) acrylic acid ester represented by

In the above formula (II), R ³ represents a hydrogen atom or a methyl group, n represents an integer of 1 to 8, and R ⁴ represents a hydrogen atom, an alkyl group, an aralkyl group, or an aryl group. When R ⁴ is an alkyl group, the carbon number can be about 1 to 9, and when it is an aralkyl group, the carbon number is about 7 to 11, and when it is an aryl group, the carbon number is 6 Can be on the order of -10.

Examples of the alkyl group having 1 to 9 carbon atoms constituting R ⁴ in the formula (II) include methyl, butyl and nonyl, and examples of the aralkyl group having 7 to 11 carbon atoms include benzyl, phenethyl and naphthylmethyl. Examples of the aryl group having 6 to 10 carbon atoms include phenyl, tolyl, naphthyl and the like.

  Specific examples of the phenoxyethyl group-containing (meth) acrylic acid ester represented by the formula (II) are: (meth) acrylic acid 2-phenoxyethyl, (meth) acrylic acid 2- (2-phenoxyethoxy) ethyl, ethylene oxide (Meth) acrylic acid ester of modified nonylphenol, 2- (o-phenylphenoxy) ethyl (meth) acrylate, and the like. The phenoxyethyl group-containing (meth) acrylic acid ester may be used alone or in combination of two or more. Among them, phenoxyethyl group-containing (meth) acrylic acid esters include 2-methoxyethyl (meth) acrylate, 2- (o-phenylphenoxy) ethyl (meth) acrylate and / or 2- (2) (meth) acrylic acid. -Phenoxyethoxy) ethyl is preferably included.

  Content of the structural unit derived from the monomer which has an aromatic ring is 0-20 weight% (for example, 6-12 weight%) normally in all the structural units which comprise (meth) acrylic-type resin (A). However, in order to make the glass transition temperature of (meth) acrylic-type resin (A) into the predetermined range mentioned later, it may be preferable not to contain the structural unit derived from the monomer which has an aromatic ring.

  The (meth) acrylic resin (A) is a monomer other than the (meth) acrylic acid ester of the formula (I) described above, a monomer having a polar functional group, and a monomer having an aromatic ring (hereinafter referred to as “monomer”). And may be a structural unit derived from other monomer. Examples of other monomers include structural units derived from (meth) acrylic acid esters having an alicyclic structure in the molecule, structural units derived from styrene monomers, and vinyl monomers. Examples include a structural unit, a structural unit derived from a monomer having a plurality of (meth) acryloyl groups in the molecule, and a structural unit derived from a (meth) acrylamide compound. Other monomers may be used alone or in combination of two or more.

  The alicyclic structure in the (meth) acrylic acid ester having an alicyclic structure in the molecule is a cycloparaffin structure having usually 5 or more carbon atoms, preferably about 5 to 7 carbon atoms. Specific examples of the (meth) acrylic acid ester having an alicyclic structure include isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, cyclododecyl (meth) acrylate, ( Including methyl cyclohexyl acrylate, trimethyl cyclohexyl (meth) acrylate, t-butyl cyclohexyl (meth) acrylate, cyclohexyl phenyl (meth) acrylate, cyclohexyl α-ethoxy acrylate, and the like.

  Specific examples of the styrenic monomer include styrene; alkyl styrene such as methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene, octyl styrene; Halogenated styrene such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, iodostyrene; nitrostyrene, acetylstyrene, methoxystyrene, divinylbenzene and the like.

  Specific examples of vinyl monomers include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate, and other fatty acid vinyl esters; vinyl chloride, vinyl halides such as vinyl bromide; Examples include vinylidene halides such as vinylidene chloride; nitrogen-containing aromatic vinyls such as vinylpyridine, vinylpyrrolidone and vinylcarbazole; conjugated diene monomers such as butadiene, isoprene and chloroprene; acrylonitrile, methacrylonitrile and the like.

  Specific examples of monomers having a plurality of (meth) acryloyl groups in the molecule include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and 1,9-nonanediol. 2 (meth) in the molecule such as di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate A monomer having an acryloyl group; a monomer having three (meth) acryloyl groups in the molecule such as trimethylolpropane tri (meth) acrylate.

  Specific examples of the (meth) acrylamide compound include N-methylol (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, N- (3-hydroxypropyl) (meth) acrylamide, and N- (4-hydroxy). Butyl) (meth) acrylamide, N- (5-hydroxypentyl) (meth) acrylamide, N- (6-hydroxyhexyl) (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meta) ) Acrylamide, N-isopropyl (meth) acrylamide, N- (3-dimethylaminopropyl) (meth) acrylamide, N- (1,1-dimethyl-3-oxobutyl) (meth) acrylamide, N- [2- (2 -Oxo-1-imidazolidinyl) ethyl] (meth) acrylamide, -Acryloylamino-2-methyl-1-propanesulfonic acid, N- (methoxymethyl) acrylamide, N- (ethoxymethyl) (meth) acrylamide, N- (propoxymethyl) (meth) acrylamide, N- (1-methyl) Ethoxymethyl) (meth) acrylamide, N- (1-methylpropoxymethyl) (meth) acrylamide, N- (2-methylpropoxymethyl) (meth) acrylamide [also known as N- (isobutoxymethyl) (meth) acrylamide] N- (butoxymethyl) (meth) acrylamide, N- (1,1-dimethylethoxymethyl) (meth) acrylamide, N- (2-methoxyethyl) (meth) acrylamide, N- (2-ethoxyethyl) ( (Meth) acrylamide, N- (2-propoxyethyl) (meth) Kurylamide, N- [2- (1-methylethoxy) ethyl] (meth) acrylamide, N- [2- (1-methylpropoxy) ethyl] (meth) acrylamide, N- [2- (2-methylpropoxy) ethyl ] (Meth) acrylamide [Alternative name: N- (2-isobutoxyethyl) (meth) acrylamide], N- (2-butoxyethyl) (meth) acrylamide, N- [2- (1,1-dimethylethoxy) ethyl ] (Meth) acrylamide and the like. Among these, N- (methoxymethyl) acrylamide, N- (ethoxymethyl) acrylamide, N- (propoxymethyl) acrylamide, N- (butoxymethyl) acrylamide, and N- (2-methylpropoxymethyl) acrylamide are preferably used.

  The (meth) acrylic resin (A) contains 0 to 20% by weight, preferably 0 to 10% by weight, of other monomers in all the structural units constituting the resin.

  The pressure-sensitive adhesive composition may contain two or more (meth) acrylic resins belonging to the (meth) acrylic resin (A). The pressure-sensitive adhesive composition may contain another (meth) acrylic resin different from the (meth) acrylic resin (A). Examples of other (meth) acrylic resins are (meth) acrylic resins having a structural unit derived from the (meth) acrylic acid ester of the formula (I) and having no polar functional group. However, the pressure-sensitive adhesive composition preferably contains the (meth) acrylic resin (A) as a main component, and the content of the (meth) acrylic resin (A) is that of all (meth) acrylic resins. In the total, it is preferably 60% by weight or more, more preferably 80% by weight or more, and further preferably 90% by weight or more.

  The (meth) acrylic resin (A) has a glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) of −55 ° C. or higher, preferably -50 ° C. or higher. According to the pressure-sensitive adhesive composition according to the present invention containing the (meth) acrylic resin (A) having a Tg of −55 ° C. or higher, the adhesiveness between the pressure-sensitive adhesive layer and the optical member and the durability of the pressure-sensitive adhesive layer are improved. Can be improved. From the viewpoint of adhesion between the pressure-sensitive adhesive layer and the optical member, the Tg of the (meth) acrylic resin (A) is usually −20 ° C. or lower, preferably −25 ° C. or lower, more preferably −30 ° C. It is as follows.

  The (meth) acrylic resin (A) preferably has a weight average molecular weight (Mw) in terms of standard polystyrene by gel permeation chromatography (GPC) in the range of 500,000 to 2,000,000, and 600,000 to 1,800,000. It is more preferable that it is in the range. When the Mw is 500,000 or more, the adhesiveness between the pressure-sensitive adhesive layer and the optical member in a high-temperature and high-humidity environment is improved, and the possibility of floating or peeling between the pressure-sensitive adhesive layer and the optical member is low. In addition, the reworkability of the pressure-sensitive adhesive layer tends to be improved. In addition, when the adhesive layer is bonded to the optical member when the Mw is 2 million or less, even if the dimension of the optical member changes, the adhesive layer tends to follow the dimensional change and easily fluctuate. It is advantageous in terms of adhesion between the pressure-sensitive adhesive layer and the optical member and durability of the pressure-sensitive adhesive layer, and due to the above-mentioned followability, when the optical member with the pressure-sensitive adhesive layer is applied to a liquid crystal display device, the peripheral edge of the liquid crystal cell There is no difference between the brightness of the part and the brightness of the center part, and white spots and color unevenness tend to be suppressed. The molecular weight distribution represented by the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is usually about 2 to 10, preferably 3 to 8.

  The (meth) acrylic resin (A) and other (meth) acrylic resins that can optionally be used together are produced by known methods such as solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization. be able to. In the production of the (meth) acrylic resin, a polymerization initiator is usually used. A polymerization initiator is used about 0.001-5 weight part with respect to a total of 100 weight part of all the monomers used for manufacture of (meth) acrylic-type resin. Moreover, you may manufacture a (meth) acrylic-type resin by the method of advancing superposition | polymerization by active energy rays, such as an ultraviolet-ray, for example.

  As the polymerization initiator, a thermal polymerization initiator, a photopolymerization initiator, or the like is used. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone. Examples of the thermal polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl-2,2′-azobis (2-methylpropio) Azo), 2,2′-azobis (2-hydroxymethylpropionitrile); lauryl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, tert-butyl peroxybenzoate, cumene hydroper Oxide, diisopropyl peroxydicarbonate, dipropyl peroxydicarbonate, ter Organic peroxides such as butyl peroxyneodecanoate, tert-butyl peroxypivalate, (3,5,5-trimethylhexanoyl) peroxide; such as potassium persulfate, ammonium persulfate, hydrogen peroxide And inorganic peroxides. A redox initiator or the like using a peroxide and a reducing agent in combination can also be used as the polymerization initiator.

  As a method for producing the (meth) acrylic resin, the solution polymerization method is preferable among the methods shown above. As an example of the solution polymerization method, a monomer and an organic solvent to be used are mixed, a thermal polymerization initiator is added under a nitrogen atmosphere, and the temperature is about 40 to 90 ° C., preferably about 50 to 80 ° C. for 3 to 15 hours. It is about stirring. In order to control the reaction, a monomer or a thermal polymerization initiator may be added continuously or intermittently during the polymerization, or may be added in a state dissolved in an organic solvent. Examples of the organic solvent include aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; aliphatic alcohols such as propyl alcohol and isopropyl alcohol; acetone, methyl ethyl ketone, and methyl isobutyl ketone. Such ketones can be used.

[2] Isocyanate-based crosslinking agent (B)
The pressure-sensitive adhesive composition further contains an isocyanate-based crosslinking agent (B). This isocyanate-based crosslinking agent (B) is an isocyanate-based crosslinking agent that has two or more isocyanate groups in the molecule, and at least one isocyanate group is bonded to a carbon atom constituting the aliphatic skeleton. By using this isocyanate type crosslinking agent (B) as a crosslinking agent, the adhesiveness of an adhesive layer and an optical member and durability of an adhesive layer can be improved.

  The aliphatic skeleton means a skeleton other than an aromatic ring, and includes, for example, an alicyclic structure in addition to a chain or branched hydrocarbon group. The isocyanate-based crosslinking agent (B) can contain an aromatic ring as long as it has an isocyanate group bonded to the carbon atom constituting the aliphatic skeleton. A suitable example of the isocyanate-based crosslinking agent (B) is an isocyanate-based crosslinking agent in which an isocyanate group is bonded to a carbon atom of a methylene group constituting an aliphatic skeleton.

  The number of methylene groups constituting the aliphatic skeleton, that is, the number of carbon atoms constituting the aliphatic skeleton is usually 1 to 15, preferably 1 to 10.

  A specific example of the isocyanate-based crosslinking agent (B) is an aliphatic isocyanate-based crosslinking agent that is composed of an aliphatic skeleton and does not contain an aromatic ring. Examples of the aliphatic isocyanate-based crosslinking agent include 1,6-hexamethylene diisocyanate, 1,4-tetramethylene diisocyanate, 2-methyl-1,5-pentane diisocyanate, 3-methyl-1,5-pentane diisocyanate, and lysine diisocyanate. , Isophorone diisocyanate, cyclohexyl diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tetramethylxylene diisocyanate and the like.

  Another specific example of the isocyanate-based crosslinking agent (B) is an isocyanate-based crosslinking agent having an isocyanate group bonded to a carbon atom constituting the aliphatic skeleton and containing an aromatic ring. Examples of such isocyanate-based crosslinking agents include xylylene diisocyanate and the like.

  Among these, an aliphatic isocyanate-based crosslinking agent that is composed of an aliphatic skeleton and does not contain an aromatic ring is advantageous for further improving the adhesion between the pressure-sensitive adhesive layer and the optical member.

  The isocyanate-based crosslinking agent (B) is a polyhydric alcohol compound adduct of the above isocyanate compound (for example, an adduct of trimethylolpropane), an isocyanurate, a burette type compound, a polyether polyol, a polyester polyol, an acrylic polyol, It includes derivatives such as urethane prepolymer type isocyanate compounds that have undergone addition reaction with polybutadiene polyol, polyisoprene polyol and the like. An isocyanate type crosslinking agent (B) may be used individually by 1 type, and may use 2 or more types together.

  Content of isocyanate type crosslinking agent (B) is 0.1-1 weight part with respect to 100 weight part of (meth) acrylic-type resin (A), Preferably it is 0.2-0.9 weight part. . When the content of the isocyanate-based crosslinking agent (B) is less than 0.1 parts by weight, depending on the material of the surface of the optical member on which the pressure-sensitive adhesive layer is laminated, the adhesiveness between the pressure-sensitive adhesive layer and the optical member is insufficient. Become. Further, depending on the material of the surface of the optical member on which the pressure-sensitive adhesive layer is laminated, durability when the pressure-sensitive adhesive layer is bonded to the optical member is lowered. When the content of the isocyanate-based crosslinking agent (B) exceeds 1 part by weight, the adhesiveness between the pressure-sensitive adhesive layer and the optical member becomes insufficient even when sufficient curing time is taken. Further, durability when the pressure-sensitive adhesive layer is bonded to the optical member, particularly heat resistance, is lowered.

[3] Ionic compound (C)
The pressure-sensitive adhesive composition may further contain an ionic compound (C) as an antistatic agent for imparting antistatic properties to the pressure-sensitive adhesive layer. The ionic compound (C) is a compound having an inorganic cation or an organic cation and an inorganic anion or an organic anion. Two or more ionic compounds (C) may be used.

Examples of the inorganic cation include alkali metal ions such as lithium cation [Li ⁺ ], sodium cation [Na ⁺ ], and potassium cation [K ⁺ ], beryllium cation [Be ²⁺ ], and magnesium cation [Mg ²⁺ ]. And alkaline earth metal ions such as calcium cation [Ca ²⁺ ].

  Examples of the organic cation include an imidazolium cation, a pyridinium cation, a pyrrolidinium cation, an ammonium cation, a sulfonium cation, and a phosphonium cation.

  Of the cation components described above, the organic cation component is preferably used because of its excellent compatibility with the pressure-sensitive adhesive composition. Among organic cation components, pyridinium cation and imidazolium cation are particularly preferably used from the viewpoint that they are difficult to be charged when the release film provided on the pressure-sensitive adhesive layer is peeled off.

Examples of inorganic anions include chloride anions [Cl ⁻ ], bromide anions [Br ⁻ ], iodide anions [I ⁻ ], tetrachloroaluminate anions [AlCl ₄ ⁻ ], heptachlorodialuminate anions [Al ₂ Cl ₇ ⁻ ], tetrafluoroborate anion [BF ₄ ⁻ ], hexafluorophosphate anion [PF ₆ ⁻ ], perchlorate anion [ClO ₄ ⁻ ], nitrate anion [NO ₃ ⁻ ], hexafluoroarsenate anion [AsF _6] ^- ], Hexafluoroantimonate anion [SbF ₆ ⁻ ], hexafluoro niobate anion [NbF ₆ ⁻ ], hexafluoro tantalate anion [TaF ₆ ⁻ ], dicyanamide anion [(CN) ₂ N ⁻ ] and the like. It is done.

Examples of the organic anion include acetate anion [CH ₃ COO ⁻ ], trifluoroacetate anion [CF ₃ COO ⁻ ], methanesulfonate anion [CH ₃ SO ₃ ⁻ ], trifluoromethanesulfonate anion [CF ₃ SO ₃ ⁻ ], p-toluenesulfonate anion [p-CH ₃ C ₆ H ₄ SO ₃ ⁻ ], bis (fluorosulfonyl) imide anion [(FSO ₂ ) ₂ N ⁻ ], bis (trifluoromethanesulfonyl) imide anion [(CF ₃ SO ₂ ) ₂ N ⁻ ], tris (trifluoromethanesulfonyl) methanide anion [(CF ₃ SO ₂ ) ₃ C ⁻ ], dimethyl phosphinate anion [(CH ₃ ) ₂ POO ⁻ ], (poly) hydrofluorofluoride anion [ F (HF) _n ⁻ ] (n is about 1 to 3), thiocyan anion [SC N ^-], perfluorobutane sulfonate anion [C ₄ F ₉ SO ₃ ^-], bis (pentafluoroethane sulfonyl) imide anion _{[(C 2 F 5 SO 2)} 2 N - ], perfluoro butanoate anion [C ₃ F ₇ COO ⁻ ], (trifluoromethanesulfonyl) (trifluoromethanecarbonyl) imide anion [(CF ₃ SO ₂ ) (CF ₃ CO) N ⁻ ], perfluoropropane-1,3-disulfonate anion [ ⁻ O ₃ S (CF ₂ ) ₃ SO ₃ ⁻ ], carbonate anion [CO ₃ ²⁻ ] and the like.

  Among the above-mentioned anion components, an anion component containing a fluorine atom is preferably used because it gives an ionic compound (C) excellent in antistatic performance. Specific examples include a bis (fluorosulfonyl) imide anion, a hexafluorophosphate anion, or a bis (trifluoromethanesulfonyl) imide anion.

  Specific examples of the ionic compound (C) can be appropriately selected from a combination of the cation component and the anion component. When the examples of the ionic compound (C) having an organic cation are classified according to the structure of the organic cation, the following may be mentioned.

Pyridinium salt:
N-hexylpyridinium hexafluorophosphate,
N-octylpyridinium hexafluorophosphate,
N-octyl-4-methylpyridinium hexafluorophosphate,
N-butyl-4-methylrupyridinium hexafluorophosphate,
N-decylpyridinium bis (fluorosulfonyl) imide,
N-dodecylpyridinium bis (fluorosulfonyl) imide,
N-tetradecylpyridinium bis (fluorosulfonyl) imide,
N-hexadecylpyridinium bis (fluorosulfonyl) imide,
N-dodecyl-4-methylpyridinium bis (fluorosulfonyl) imide,
N-tetradecyl-4-methylpyridinium bis (fluorosulfonyl) imide,
N-hexadecyl-4-methylpyridinium bis (fluorosulfonyl) imide,
N-benzyl-2-methylpyridinium bis (fluorosulfonyl) imide,
N-benzyl-4-methylpyridinium bis (fluorosulfonyl) imide N-hexylpyridinium bis (trifluoromethanesulfonyl) imide,
N-octylpyridinium bis (trifluoromethanesulfonyl) imide,
N-octyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide,
N-butyl-4-methyllpyridinium bis (trifluoromethanesulfonyl) imide.

Imidazolium salt:
1-ethyl-3-methylimidazolium hexafluorophosphate,
1-ethyl-3-methylimidazolium p-toluenesulfonate,
1-ethyl-3-methylimidazolium bis (fluorosulfonyl) imide,
1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide,
1-butyl-3-methylimidazolium methanesulfonate,
1-butyl-3-methylimidazolium bis (fluorosulfonyl) imide.

Pyrrolidinium salt:
N-butyl-N-methylpyrrolidinium hexafluorophosphate,
N-butyl-N-methylpyrrolidinium bis (fluorosulfonyl) imide,
N-butyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl) imide.

Quaternary ammonium salt:
Tetrabutylammonium hexafluorophosphate,
Tetrabutylammonium p-toluenesulfonate,
(2-hydroxyethyl) trimethylammonium bis (trifluoromethanesulfonyl) imide,
(2-Hydroxyethyl) trimethylammonium dimethylphosphinate.

  Examples of the ionic compound (C) having an inorganic cation include the following.

Lithium bromide,
Lithium iodide,
Lithium tetrafluoroborate,
Lithium hexafluorophosphate,
Lithium thiocyanate,
Lithium perchlorate,
Lithium trifluoromethanesulfonate,
Lithium bis (fluorosulfonyl) imide,
Lithium bis (trifluoromethanesulfonyl) imide,
Lithium bis (pentafluoroethanesulfonyl) imide,
Lithium tris (trifluoromethanesulfonyl) methanide,
Lithium p-toluenesulfonate,
Sodium hexafluorophosphate,
Sodium bis (fluorosulfonyl) imide,
Sodium bis (trifluoromethanesulfonyl) imide,
Sodium p-toluenesulfonate,
Potassium hexafluorophosphate,
Potassium bis (fluorosulfonyl) imide,
Potassium bis (trifluoromethanesulfonyl) imide,
Potassium p-toluenesulfonate.

  The ionic compound (C) is preferably a solid at room temperature. Compared with the case of using an ionic compound (C) that is liquid at room temperature, the antistatic performance can be maintained for a long time. From the viewpoint of such antistatic long-term stability, the ionic compound (C) preferably has a melting point of 30 ° C. or higher, more preferably 35 ° C. or higher. On the other hand, if the melting point is too high, the compatibility with the (meth) acrylic resin (A) is deteriorated, so the melting point is preferably 90 ° C. or less, more preferably 70 ° C. or less, and even more preferably less than 50 ° C. It is.

  The content of the ionic compound (C) in the pressure-sensitive adhesive composition is preferably 0.2 to 8 parts by weight, more preferably 0.2 to 100 parts by weight of the (meth) acrylic resin (A). -5 parts by weight, more preferably 0.3-5 parts by weight, and particularly preferably 0.5-3 parts by weight. The content of the ionic compound (C) being 0.2 parts by weight or more is advantageous for improving the antistatic performance, and the content of 8 parts by weight or less is advantageous for maintaining the durability of the pressure-sensitive adhesive layer. .

[4] Silane compound (D)
The pressure-sensitive adhesive composition can further contain a silane compound (D). Thereby, the adhesiveness of an adhesive layer and optical members, such as a glass substrate, can be improved.

  Examples of the silane compound (D) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2 -Aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ) Ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxy Silane, 3-glycidoxypropyl triethoxysilane, 3-glycidoxypropyl dimethoxymethyl silane, 3-glycidoxypropyl-ethoxy dimethyl silane, and the like. Two or more silane compounds may be used.

  The silane compound (D) may be of a silicone oligomer type. When the silicone oligomer is shown in the form of a (monomer) oligomer, for example, the following can be mentioned.

3-mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer,
3-mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer,
3-mercaptopropyltriethoxysilane-tetramethoxysilane copolymer,
A copolymer containing a mercaptopropyl group, such as 3-mercaptopropyltriethoxysilane-tetraethoxysilane copolymer;
Mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer,
Mercaptomethyltrimethoxysilane-tetraethoxysilane copolymer,
Mercaptomethyltriethoxysilane-tetramethoxysilane copolymer,
A mercaptomethyl group-containing copolymer such as a mercaptomethyltriethoxysilane-tetraethoxysilane copolymer;
3-glycidoxypropyltrimethoxysilane-tetramethoxysilane copolymer,
3-glycidoxypropyltrimethoxysilane-tetraethoxysilane copolymer,
3-glycidoxypropyltriethoxysilane-tetramethoxysilane copolymer,
3-glycidoxypropyltriethoxysilane-tetraethoxysilane copolymer,
3-glycidoxypropylmethyldimethoxysilane-tetramethoxysilane copolymer,
3-glycidoxypropylmethyldimethoxysilane-tetraethoxysilane copolymer,
3-glycidoxypropylmethyldiethoxysilane-tetramethoxysilane copolymer,
Copolymers containing 3-glycidoxypropyl groups, such as 3-glycidoxypropylmethyldiethoxysilane-tetraethoxysilane copolymer;
3-methacryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer,
3-methacryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer,
3-methacryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer,
3-methacryloyloxypropyltriethoxysilane-tetraethoxysilane copolymer,
3-methacryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer,
3-methacryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer,
3-methacryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer,
A methacryloyloxypropyl group-containing copolymer such as 3-methacryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymer;
3-acryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer,
3-acryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer,
3-acryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer,
3-acryloyloxypropyltriethoxysilane-tetraethoxysilane copolymer,
3-acryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer,
3-acryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer,
3-acryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer,
Copolymers containing acryloyloxypropyl groups, such as 3-acryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymer;
Vinyltrimethoxysilane-tetramethoxysilane copolymer,
Vinyltrimethoxysilane-tetraethoxysilane copolymer,
Vinyltriethoxysilane-tetramethoxysilane copolymer,
Vinyltriethoxysilane-tetraethoxysilane copolymer,
Vinylmethyldimethoxysilane-tetramethoxysilane copolymer,
Vinylmethyldimethoxysilane-tetraethoxysilane copolymer,
Vinylmethyldiethoxysilane-tetramethoxysilane copolymer,
Vinyl group-containing copolymers such as vinylmethyldiethoxysilane-tetraethoxysilane copolymer;
3-aminopropyltrimethoxysilane-tetramethoxysilane copolymer,
3-aminopropyltrimethoxysilane-tetraethoxysilane copolymer,
3-aminopropyltriethoxysilane-tetramethoxysilane copolymer,
3-aminopropyltriethoxysilane-tetraethoxysilane copolymer,
3-aminopropylmethyldimethoxysilane-tetramethoxysilane copolymer,
3-aminopropylmethyldimethoxysilane-tetraethoxysilane copolymer,
3-aminopropylmethyldiethoxysilane-tetramethoxysilane copolymer,
Amino group-containing copolymers such as 3-aminopropylmethyldiethoxysilane-tetraethoxysilane copolymer.

  Many of the silane compounds (D) exemplified above are liquids. Content of the silane compound (D) in an adhesive composition is 0.01-10 weight part normally with respect to 100 weight part of (meth) acrylic-type resin (A), Preferably it is 0.05-5 weight. Part, more preferably 0.2 to 0.4 part by weight. When the content of the silane compound (D) is 0.01 parts by weight or more, an effect of improving the adhesion between the pressure-sensitive adhesive layer and an optical member such as a glass substrate is easily obtained. Moreover, the bleeding out of the silane compound (D) from an adhesive layer can be suppressed as content is 10 weight part or less.

[5] Other components The pressure-sensitive adhesive composition is other than a crosslinking catalyst, weathering stabilizer, tackifier, plasticizer, softener, dye, pigment, inorganic filler, light scattering fine particles, (meth) acrylic resin (A). An additive such as a resin may be contained. In addition, it is also useful to blend an ultraviolet curable compound into the pressure-sensitive adhesive composition, form an pressure-sensitive adhesive layer, and then cure by irradiating with ultraviolet rays to form a harder pressure-sensitive adhesive layer. Examples of the crosslinking catalyst include amine compounds such as hexamethylenediamine, ethylenediamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethylenetetramine, isophoronediamine, trimethylenediamine, polyamino resin, and melamine resin.

<Adhesive layer>
The pressure-sensitive adhesive layer according to the present invention includes the above-mentioned pressure-sensitive adhesive composition according to the present invention, and typically comprises the pressure-sensitive adhesive composition according to the present invention. The pressure-sensitive adhesive layer can be obtained by dissolving or dispersing each component constituting the pressure-sensitive adhesive composition in a solvent to obtain a solvent-containing pressure-sensitive adhesive composition, and then applying the composition on a base film and drying it. . The pressure-sensitive adhesive layer according to the present invention is excellent in adhesion and durability.

  The base film is generally a plastic film, and a typical example thereof is a release film (separator) that has been subjected to a release treatment. The release film is, for example, a film on which a pressure-sensitive adhesive layer of a film made of various resins such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, and polyarate is formed and subjected to release treatment such as silicone treatment. it can. For example, the pressure-sensitive adhesive composition is directly applied to the release treatment surface of the release film to form a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer with the release film is laminated on the optical member to obtain the optical member with the pressure-sensitive adhesive layer. Can do. Alternatively, the pressure-sensitive adhesive composition may be directly applied to the surface of the optical member to form a pressure-sensitive adhesive layer, and if necessary, a release film may be laminated on the outer surface of the pressure-sensitive adhesive layer to form an optical member with a pressure-sensitive adhesive layer. When the pressure-sensitive adhesive layer is provided on the surface of the optical member, it is preferable to subject the bonding surface of the optical member and / or the bonding surface of the pressure-sensitive adhesive layer to surface activation treatment, such as plasma treatment or corona treatment. More preferably, the treatment is performed.

  The thickness of the pressure-sensitive adhesive layer is preferably 10 to 45 μm, more preferably 10 to 30 μm, and still more preferably 10 to 20 μm. When the thickness of the pressure-sensitive adhesive layer is within this range, it is advantageous for adhesion between the pressure-sensitive adhesive layer and the optical member and durability when the pressure-sensitive adhesive layer is bonded to the optical member. For the same reason, the pressure-sensitive adhesive layer preferably has a gel fraction in the range of 30 to 85%.

<Optical member with adhesive layer>
The pressure-sensitive adhesive layer according to the present invention can be suitably used as a pressure-sensitive adhesive layer for bonding members, particularly optical members. The optical member with the pressure-sensitive adhesive layer according to the present invention can be, for example, one in which a pressure-sensitive adhesive layer is laminated on a certain optical member, and another optical member is laminated and bonded to the outer surface of the pressure-sensitive adhesive layer. Can be.

[1] 1st Embodiment One preferable embodiment of the optical member with an adhesive layer which concerns on this invention contains the resin film as an optical member, and the adhesive layer laminated | stacked on the at least one surface. A resin film is a surface protective film (protective film) that is bonded to optical films such as polarizers, protective films, retardation films, etc., or optical films that are protected objects, and used to protect the surface from scratches and dirt. Film).

  A polarizer is a film that has the function of extracting linearly polarized light from incident natural light, and a suitable example is that a dichroic dye such as iodine or a dichroic dye is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol resin film. It is what. The thickness of the polarizer is not particularly limited, but is usually 0.5 to 35 μm.

  The protective film is a translucent (preferably optically transparent) resin, for example, a polyolefin resin such as a chain polyolefin resin (polypropylene resin, etc.) or a cyclic polyolefin resin (norbornene resin, etc.). A cellulose resin such as triacetyl cellulose and diacetyl cellulose; a polyester resin; a polycarbonate resin; a (meth) acrylic resin; a polystyrene resin; a polyether ether ketone resin; a film made of a thermoplastic resin such as a polysulfone resin; Can be.

  Examples of the chain polyolefin-based resin include a homopolymer of a chain olefin such as a polyethylene resin and a polypropylene resin, and a copolymer composed of two or more chain olefins.

  Cyclic polyolefin resin is a general term for resins that are polymerized using cyclic olefins as polymerization units. Specific examples of cyclic polyolefin resins include ring-opening (co) polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins and chain olefins such as ethylene and propylene (typically Are random copolymers), graft polymers obtained by modifying them with unsaturated carboxylic acids or derivatives thereof, and hydrides thereof. Among these, norbornene resins using norbornene monomers such as norbornene and polycyclic norbornene monomers as cyclic olefins are preferably used.

  Cellulosic resin is a part or complete esterified product of cellulose, and examples thereof include cellulose acetate ester, propionate ester, butyrate ester, and mixed ester thereof. Of these, triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, cellulose acetate butyrate and the like are preferably used.

  The polyester-based resin is a resin other than the above cellulose-based resin having an ester bond, and is generally made of a polycondensate of a polyvalent carboxylic acid or a derivative thereof and a polyhydric alcohol. As the polyvalent carboxylic acid or a derivative thereof, a dicarboxylic acid or a derivative thereof can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylate. A diol can be used as the polyhydric alcohol, and examples thereof include ethylene glycol, propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol.

  Specific examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethyl terephthalate, and polycyclohexanedimethyl naphthalate.

  The polycarbonate resin is composed of a polymer in which monomer units are bonded via a carbonate group. The polycarbonate-based resin may be a resin called a modified polycarbonate having a modified polymer skeleton, a copolymer polycarbonate, or the like.

  The (meth) acrylic resin can be a polymer having a methacrylic acid ester as a main monomer, and is preferably a copolymer in which a small amount of other comonomer components are copolymerized. The (meth) acrylic resin is more preferably a copolymer of methyl methacrylate and methyl acrylate, and a third monofunctional monomer may be further copolymerized.

  Examples of the third monofunctional monomer include other than methyl methacrylate such as ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxyethyl methacrylate. Acrylates such as ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate; 2- (hydroxy Hydroxyalkyl acrylics such as methyl) methyl acrylate, 2- (1-hydroxyethyl) methyl acrylate, 2- (hydroxymethyl) ethyl acrylate, 2- (hydroxymethyl) butyl acrylate Esters; unsaturated acids such as methacrylic acid and acrylic acid; halogenated styrenes such as chlorostyrene and bromostyrene; substituted styrenes such as vinyltoluene and α-methylstyrene; such as acrylonitrile and methacrylonitrile Unsaturated nitriles; unsaturated acid anhydrides such as maleic anhydride and citraconic anhydride; unsaturated imides such as phenylmaleimide and cyclohexylmaleimide. The third monofunctional monomer may be used alone or in combination of two or more.

  A polyfunctional monomer may be further copolymerized with the (meth) acrylic resin. Examples of the polyfunctional monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, nonaethylene glycol di (meth) acrylate, Ethylene glycol such as tetradecaethylene glycol di (meth) acrylate or its both end hydroxyl groups esterified with acrylic acid or methacrylic acid; propylene glycol or its both end hydroxyl groups esterified with acrylic acid or methacrylic acid Dihydric alcohol water such as neopentyl glycol di (meth) acrylate, hexanediol di (meth) acrylate, butanediol di (meth) acrylate Esterified with acrylic acid or methacrylic acid group; bisphenol A, alkylene oxide adduct of bisphenol A, or those obtained by esterifying both hydroxyl groups of these halogen-substituted products with acrylic acid or methacrylic acid; trimethylolpropane, Those obtained by esterifying polyhydric alcohols such as pentaerythritol with acrylic acid or methacrylic acid, and those obtained by ring-opening addition of an epoxy group of glycidyl acrylate or glycidyl methacrylate to these terminal hydroxyl groups; succinic acid, adipic acid, terephthalic acid, Phthalic acid, dibasic acids such as halogen-substituted products, and alkylene oxide adducts thereof obtained by ring-opening addition of an epoxy group of glycidyl acrylate or glycidyl methacrylate; aryl (meth) acrylate ; Aromatic divinyl compounds such as divinylbenzene, and the like. Of these, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and neopentyl glycol dimethacrylate are preferably used.

  The (meth) acrylic resin may be modified by further reacting between functional groups of the copolymer. As the reaction, for example, demethanol condensation reaction in a polymer chain between a methyl ester group of methyl acrylate and a hydroxyl group of methyl 2- (hydroxymethyl) acrylate, a carboxyl group of acrylic acid and 2- (hydroxymethyl) acrylic Examples thereof include a dehydration condensation reaction in the polymer chain with a hydroxyl group of methyl acid. The (meth) acrylic resin may have any structure of a glutarimide derivative, a glutaric anhydride derivative, or a lactone ring structure.

  The (meth) acrylic resin may contain an additive as necessary. Examples of the additive include a lubricant, an antiblocking agent, a heat stabilizer, an antioxidant, an antistatic agent, a light resistance agent, an impact resistance improver, and a surfactant.

  The (meth) acrylic resin may contain acrylic rubber particles from the viewpoints of film-formability on the film and impact resistance of the film. Acrylic rubber particles are particles having an elastic polymer mainly composed of an acrylate ester as an essential component. The acrylic rubber particles have a single-layer structure consisting essentially of this elastic polymer, or one elastic polymer. The thing of the multilayered structure used as a layer is mentioned. Examples of this elastic polymer include a cross-linked elastic copolymer obtained by copolymerizing an alkyl acrylate as a main component with another vinyl monomer and a cross-linkable monomer copolymerizable therewith. Examples of the alkyl acrylate as the main component of the elastic polymer include those having an alkyl group with about 1 to 8 carbon atoms, such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and the like. In particular, acrylic acid having an alkyl group having 4 or more carbon atoms is preferably used. Examples of the other vinyl monomer copolymerizable with the alkyl acrylate include a compound having one polymerizable carbon-carbon double bond in the molecule, and more specifically, a methacrylic compound such as methyl methacrylate. Examples thereof include acid esters, aromatic vinyl compounds such as styrene, vinylcyan compounds such as acrylonitrile, and the like. Examples of the crosslinkable monomer include a crosslinkable compound having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, ethylene glycol di (meth) acrylate, butanediol di ( Examples include (meth) acrylates of polyhydric alcohols such as (meth) acrylate, alkenyl esters of (meth) acrylic acid such as allyl (meth) acrylate, and divinylbenzene.

  A laminate of a film made of (meth) acrylic resin not containing rubber particles and a film made of (meth) acrylic resin containing rubber particles can also be used as a protective film.

  The retardation film is an optical film exhibiting optical anisotropy, and in addition to a resin that can be used for the protective film, for example, a polyvinyl alcohol resin, a polyarylate resin, a polyimide resin, and a polyether sulfone resin. By stretching a resin film made of polyvinylidene fluoride / polymethyl methacrylate resin, liquid crystal polyester resin, saponified ethylene-vinyl acetate copolymer, polyvinyl chloride resin, etc. to about 1.01 to 6 times It can be a stretched film obtained. Among them, a stretched film obtained by uniaxially stretching or biaxially stretching a polycarbonate resin film, a cycloolefin resin film, a (meth) acrylic resin film, or a cellulose resin film is preferable. In the present specification, a zero retardation film is also included in the retardation film (however, it can also be used as a protective film). In addition, a film called a uniaxial retardation film, a wide viewing angle retardation film, a low photoelastic modulus retardation film, or the like is also applicable as the retardation film.

The zero Letters retardation film in-plane retardation value R _e and the thickness direction retardation R _th means a film are both -15～15Nm. This retardation film is suitably used for an IPS mode liquid crystal display device. Plane retardation value R _e and the thickness direction retardation R _th are preferably both -10～10Nm, more preferably both -5～5Nm. Here plane retardation value refers R _e and the thickness direction retardation R _th is a value at a wavelength of 590 nm.

The in-plane retardation value _Re and the thickness direction retardation value R _th are respectively expressed by the following formulas:
_{R e = (n x -n y} ) × d
R _th = [(n _x + _ny ) / 2−n _z ] × d
Defined by Wherein, n _x is a refractive index in a slow axis direction (x-axis direction) in the film plane, n _y is the fast axis direction in the film plane of the (y-axis direction orthogonal to the x-axis in a plane) It is a refractive index, _nz is the refractive index in the film thickness direction (z-axis direction perpendicular to the film surface), and d is the thickness of the film.

  As the zero retardation film, for example, a resin film made of a polyolefin resin such as a cellulose resin, a chain polyolefin resin, and a cyclic polyolefin resin, a polyethylene terephthalate resin, or a (meth) acrylic resin can be used. In particular, a cellulose resin, a polyolefin resin, or a (meth) acrylic resin is preferably used because the retardation value is easily controlled and easily available. For example, a retardation film can be obtained by laminating a (meth) acrylic resin on one or both sides of a retardation developing layer made of a resin different from a (meth) acrylic resin.

  Moreover, the film which expressed optical anisotropy by application | coating and orientation of a liquid crystalline compound, and the film which expressed optical anisotropy by application | coating of an inorganic layered compound can also be used as retardation film. In such a retardation film, a so-called temperature compensation type retardation film, and a rod-like liquid crystal sold under the trade name “NH film” from JX Nippon Mining & Energy Co., Ltd. are tilted. Film, a film with a disc-shaped liquid crystal sold under the trade name “WV film” from FUJIFILM Corporation, and a complete biaxial film sold under the trade name “VAC film” from Sumitomo Chemical Co., Ltd. Examples of the orientation type film include a biaxial orientation type film sold by Sumitomo Chemical Co., Ltd. under the trade name “new VAC film”.

  On the other hand, a surface protective film is a film used for the purpose of protecting the surface of an optical film or the like as an object to be protected from scratches and dirt. For example, a polarizer, a protective film, or an optical member for a liquid crystal display device. Various optical films such as phase difference films, light diffusion sheets, and reflective sheets are usually in a state where a surface protective film is bonded to the surface (the surface on the side opposite to the pressure-sensitive adhesive layer when the pressure-sensitive adhesive layer is provided on one side). It is in circulation. The surface protective film is usually peeled off after the optical film is bonded to a liquid crystal cell or the like.

  Examples of the substrate for the surface protective film include polyolefin resins such as polyethylene, polypropylene, and polymethylpentene; fluorinated polyolefin resins such as polyvinyl fluoride, polyvinylidene fluoride, and polyfluorinated ethylene; polyethylene naphthalate, polyethylene Polyester resins such as terephthalate, polybutylene terephthalate, polyethylene terephthalate / isophthalate copolymer; polyamides such as nylon 6, nylon 6,6; polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate Copolymer, ethylene-vinyl alcohol copolymer, vinyl polymer such as polyvinyl alcohol and vinylon; cellulose resin such as triacetyl cellulose, diacetyl cellulose and cellophane; Methyl methacrylate, polyethyl methacrylate, polyethyl acrylate, such as butyl polyacrylate (meth) acrylic resin and the like; polystyrene, polycarbonate, polyarylate, polyimide, and the like. The optical member with the pressure-sensitive adhesive layer according to the present invention in which the resin film is a surface protective film is obtained by providing a pressure-sensitive adhesive layer on this substrate.

  In the optical member with the pressure-sensitive adhesive layer according to the present embodiment, it is preferable that the above-mentioned release film is attached to the surface of the pressure-sensitive adhesive layer and is temporarily protected until use. The optical member with the pressure-sensitive adhesive layer according to this embodiment to which the release film is attached is formed by applying the pressure-sensitive adhesive composition on the release film to form a pressure-sensitive adhesive layer, and further adding a resin film to the obtained pressure-sensitive adhesive layer. Can be produced by a method of laminating a film, a method of applying a pressure-sensitive adhesive composition on a resin film, forming a pressure-sensitive adhesive layer, and attaching a release film to the surface of the pressure-sensitive adhesive.

[2] Second Embodiment Another preferred embodiment of the optical member with the pressure-sensitive adhesive layer according to the present invention includes a laminate of resin films and a pressure-sensitive adhesive layer laminated on at least one surface thereof. The laminate of the resin film is preferably an optical film laminate selected from optical films such as a polarizer, a protective film, and a retardation film. A typical example of a laminate of optical films is a polarizing plate. Also in the optical member with the pressure-sensitive adhesive layer according to the present embodiment, it is preferable to attach a release film to the surface of the pressure-sensitive adhesive layer and protect it temporarily until use.

  As a polarizing plate, a linearly polarizing plate having a property of absorbing linearly polarized light having a vibrating surface in a certain direction incident on the film surface and transmitting linearly polarized light having a vibrating surface orthogonal to the polarizing surface, and in a certain direction incident on the film surface Examples include a polarizing separation plate having a property of reflecting linearly polarized light having a vibration surface and transmitting linearly polarized light having a vibration surface orthogonal to the polarization plane, and an elliptically polarizing plate in which a retardation film is laminated on a linear polarizing plate.

  The linearly polarizing plate generally has a configuration in which the above protective film is bonded to one side or both sides of the above polarizer. When a protective film is bonded on both surfaces of a polarizer, an adhesive layer can be formed on at least one surface of the protective film. When bonding a protective film only to the single side | surface of a polarizer, an adhesive layer can be formed in the surface (surface where the protective film is not bonded) of a polarizer. The elliptically polarizing plate is obtained by laminating a retardation film on a linear polarizing plate, and the linear polarizing plate generally has the same configuration as above. When laminating an adhesive layer on an elliptically polarizing plate, the adhesive layer is usually laminated on the retardation film side.

  The specific example of the optical member with an adhesive layer in case an optical member is a polarizing plate is demonstrated with reference to drawings. In the example shown in FIG. 1, a polarizing plate 10 is configured by sticking a protective film 3 having a surface treatment layer 2 on one surface of a polarizer 1 on the surface opposite to the surface treatment layer 2. The pressure-sensitive adhesive layer 20 is provided on the surface of the polarizer 1 opposite to the protective film 3, and a pressure-sensitive adhesive layer-attached polarizing plate (optical member with a pressure-sensitive adhesive layer) 25 is configured. The pressure-sensitive adhesive layer 20 can be bonded to the glass substrate 30 on the surface opposite to the polarizing plate 5, and the glass substrate 30 will be described later.

  The polarizing plate 25 with an adhesive layer shown in FIG. 2 is the same as FIG. 1 except that the polarizing plate 10 includes a second protective film 4 attached to the other surface of the polarizer 1. The pressure-sensitive adhesive layer 20 is laminated on the outer surface of the second protective film 4. The polarizing plate with pressure-sensitive adhesive layer 25 shown in FIG. 3 is the same as FIG. 1 except that the polarizing plate 10 includes a retardation film 7 that is bonded to the other surface of the polarizer 1 via an interlayer pressure-sensitive adhesive 8. It is. The polarizing plate with pressure-sensitive adhesive layer 25 shown in FIG. 4 is the same as that shown in FIG. 2 except that the polarizing plate 10 includes a retardation film 7 that is bonded to the outer surface of the second protective film 4 via an interlayer pressure-sensitive adhesive 8. Is the same. In the example shown in FIGS. 3 and 4, the pressure-sensitive adhesive layer 20 is stuck to the retardation film 7.

  The surface treatment layer 2 formed on the surface of the protective film 3 can be a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, or the like. Of these, a plurality of layers may be provided. When the polarizing plate 10 includes the retardation film 7 as in the example shown in FIGS. 3 and 4, if the liquid crystal display device is a small and medium size, a preferable example of the retardation film 7 is a quarter wavelength plate. Can be mentioned. In this case, the polarizer 1 and the retardation film 7 are generally arranged so that the absorption axis of the polarizer 1 and the slow axis of the retardation film 7 intersect each other at about 45 degrees, but the angle is set to 45 according to the characteristics of the liquid crystal cell. There may be some deviation from the degree. On the other hand, in the case of a large liquid crystal display device such as a television, a retardation film 7 having various retardation values according to the characteristics of the liquid crystal cell is used for the purpose of phase difference compensation and viewing angle compensation of the liquid crystal cell. . In this case, the polarizer 1 is generally arranged so that the absorption axis of the polarizer 1 and the slow axis of the retardation film 7 are substantially orthogonal or substantially parallel. When the retardation film 7 is composed of a quarter wavelength plate, a uniaxial or biaxial stretched film is preferably used. In addition, when the retardation film 7 is provided for the purpose of retardation compensation or viewing angle compensation of a liquid crystal cell, in addition to uniaxial or biaxial stretching film, a film oriented in the thickness direction in addition to uniaxial or biaxial stretching. What is called an optical compensation film, such as a film obtained by applying a retardation-expressing substance such as liquid crystal on a support film and fixing the orientation, can also be used as the retardation film 7.

  A common (meth) acrylic pressure-sensitive adhesive is usually used for the interlayer pressure-sensitive adhesive 8 in FIGS. 3 and 4, but it is of course possible to form a pressure-sensitive adhesive layer according to the present invention. In the case where the absorption axis of the polarizer 1 and the slow axis of the retardation film 7 are arranged so as to be substantially orthogonal or substantially parallel, as in the large liquid crystal display device described above, an interlayer adhesive is used. Instead of 8, it is also possible to use an adhesive. Examples of the adhesive include an aqueous adhesive that is composed of an aqueous solution or an aqueous dispersion and exhibits adhesive strength by evaporating water as a solvent, and an ultraviolet curable adhesive that is cured by ultraviolet irradiation and exhibits adhesive strength. Etc. Bonding of the polarizer 1 and the protective films 3 and 4 is also usually performed using an adhesive.

  Since the pressure-sensitive adhesive layer includes the pressure-sensitive adhesive composition according to the present invention, the optical member with the pressure-sensitive adhesive layer according to the present embodiment has good adhesion and durability between the pressure-sensitive adhesive layer and the optical member. According to the present invention, even if the surface of the optical member to which the pressure-sensitive adhesive layer is bonded is a surface that is difficult to be activated by a conventional surface activation treatment such as corona treatment or plasma treatment, An optical member with a pressure-sensitive adhesive layer having good adhesion and durability between the adhesive layer and the optical member can be obtained. The surface that is difficult to be activated by the surface activation treatment herein is, for example, a surface having a contact angle change rate of 40% or less, further 30% or less when the corona treatment is performed. The contact angle change rate is usually 0.1% or more, preferably 0.5% or more.

Contact angle change rate is expressed by the following formula:
Contact angle change rate (%) = {(contact angle before corona treatment−contact angle after corona treatment) / contact angle before corona treatment} × 100
Defined by The contact angle after corona treatment refers to the above surface subjected to a corona treatment once under the conditions of an output of 0.3 kW and a line speed of 10 m / min, and then left for 24 hours in an environment of a temperature of 23 ° C. and a relative humidity of 60%. The contact angle when The contact angle is a contact angle with respect to water, and its unit is “°”.

  The contact angle change rate when the corona treatment is performed differs depending on the constituent material of the surface of the optical member. Examples of the thermoplastic resin having a contact angle change rate of 40% or less include (meth) acrylic resins, cellulose resins, polyester resins, and polycarbonate resins. The surface of the optical member composed of these thermoplastic resins can be the surface of an optical film such as a protective film or a retardation film.

[3] Third Embodiment Still another preferred embodiment of the optical member with an adhesive layer according to the present invention is further provided on the outer surface of the adhesive layer in the optical member with an adhesive layer according to the first or second embodiment. Another optical member is laminated and bonded. The other optical member is preferably a glass substrate, and FIGS. 1 to 4 also show a state where the polarizing plate with the adhesive layer according to the second embodiment is bonded to the glass substrate 30. .

  Examples of the glass substrate 30 include a glass substrate of a liquid crystal cell, an antiglare glass, and a glass for sunglasses. Examples of the material of the glass substrate 30 include soda lime glass, low alkali glass, non-alkali glass, and the like. Among these, the glass substrate is preferably a glass substrate of a liquid crystal cell.

  Normally, a polarizing plate is laminated on both surfaces of the liquid crystal cell via an adhesive layer. Of these polarizing plates, only the polarizing plate disposed on the front side (viewing side) of the liquid crystal cell is included in the present invention. The polarizing plate with an adhesive layer which concerns may be sufficient, and only the polarizing plate arrange | positioned at the back side (backlight side) of a liquid crystal cell may be a polarizing plate with an adhesive layer which concerns on this invention, These Both may be the polarizing plate with an adhesive layer which concerns on this invention. The driving method of the liquid crystal cell may be any conventionally known method. The polarizing plate disposed on the back side (backlight side) usually does not have the surface treatment layer 2. Various optical films known to be disposed on the back side of the liquid crystal cell, such as a brightness enhancement film, a light collecting film, and a diffusion film, can also be provided on the outer surface of the outer polarizing plate disposed on the back side.

  An optical member with an adhesive layer such as a polarizing plate with an adhesive layer can be suitably used for a liquid crystal display device. The liquid crystal display device includes, for example, personal computers including notebook type, desktop type, PDA (Personal Digital Assistant) and the like; various mobile devices such as smartphones and tablet terminals; TVs; in-vehicle displays; electronic dictionaries; digital cameras; It can be suitably used as a liquid crystal display device for video cameras, electronic desk calculators, watches, and the like.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, this invention is not limited by these examples. Hereinafter, the part and% showing usage-amount thru | or content are a basis of weight unless there is particular notice.

<Production Examples 1 to 9: Production of (meth) acrylic resin for pressure-sensitive adhesive layer>
Monomer mixture having a monomer composition shown in Table 1 (% by weight when the total amount of monomers is 100% by weight) and diluted with ethyl acetate in a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer and a stirrer The internal temperature was raised to 55 ° C. while substituting the air in the apparatus with nitrogen gas to make it oxygen-free. Thereafter, a total amount of a solution of azobisisobutyronitrile (polymerization initiator) dissolved in ethyl acetate was added. After adding the initiator, the temperature was maintained at this temperature for 1 hour, and then ethyl acetate was continuously added into the reaction vessel while maintaining the internal temperature at 54 to 56 ° C., and the concentration of (meth) acrylic resin was 35% by weight At that time, the addition of ethyl acetate was stopped, and the temperature was kept at this temperature until 12 hours had elapsed from the start of the addition of ethyl acetate. Finally, ethyl acetate was added to adjust the concentration of the (meth) acrylic resin to 20% by weight to prepare an ethyl acetate solution of the (meth) acrylic resin.

  The weight average molecular weight (Mw) and glass transition temperature (Tg) of the obtained (meth) acrylic resin were measured. Mw has 4 columns of “TSKgel XL” manufactured by Tosoh Corp. and “Shodex GPC KF-802” manufactured by Showa Denko Co., Ltd. A total of 5 were connected in series, and tetrahydrofuran was used as an eluent, and the measurement was performed in terms of standard polystyrene under the conditions of a sample concentration of 5 mg / mL, a sample introduction amount of 100 μL, a temperature of 40 ° C., and a flow rate of 1 mL / min. Tg is measured using a differential scanning calorimeter (DSC) “EXSTAR DSC6000” manufactured by SII Nano Technology Co., Ltd. under a nitrogen atmosphere under a measurement temperature range of −80 to 50 ° C. and a heating rate of 10 ° C./min. did. Table 1 summarizes the monomer composition (% by weight) of the monomer mixture used and the Mw and Tg of the obtained (meth) acrylic resin.

Abbreviations in the column of “Monomer composition” in Table 1 mean the following monomers.
BA: butyl acrylate,
EHA: 2-ethylhexyl acrylate
MA: methyl acrylate,
AA: acrylic acid,
HEA: 2-hydroxyethyl acrylate.

<Examples 1 to 10, Comparative Examples 1 to 4>
(1) Preparation of pressure-sensitive adhesive composition The crosslinking agent (B) and ionic compound (C) shown in Table 2 with respect to 100 parts by weight of the solid content of the (meth) acrylic resin (A) obtained in the above production example. , And the silane compound (D) were mixed in the amounts (parts by weight) shown in Table 2, and ethyl acetate was added so that the solid content concentration was 28% by weight to prepare a solution of the pressure-sensitive adhesive composition. The compounding amount of each compounding component shown in Table 2 is the number of parts by weight as an active ingredient contained therein when the product used contains a solvent or the like.

The details of each compounding component shown in abbreviations in Table 2 are as follows.
B1: Ethyl acetate solution of trimethylolpropane adduct of m-xylylene diisocyanate (solid content concentration 75%), “Takenate D-110N” obtained from Mitsui Chemicals,
B2: Isocyanurate of hexamethylene diisocyanate, liquid with almost 100% active ingredient, “Coronate HXR” obtained from Nippon Polyurethane Co., Ltd.
B3: Ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solid content concentration 75%), “Coronate L” obtained from Nippon Polyurethane Co., Ltd.
B4: Ethyl acetate solution of isocyanurate form of tolylene diisocyanate (solid content concentration 50%), “Takenate D-204N” obtained from Mitsui Chemicals, Inc.
C1: N-butyl-4-methylpyridinium hexafluorophosphate,
S1: 3-glycidoxypropyltrimethoxysilane, “KBM403” obtained from Shin-Etsu Chemical Co., Ltd.

(2) Production of pressure-sensitive adhesive layer Each pressure-sensitive adhesive composition prepared in (1) above was a release film composed of a polyethylene terephthalate film subjected to a release treatment [“PLR-382051” obtained from Lintec Corporation]. An adhesive layer (pressure-sensitive adhesive sheet) was prepared by applying to the mold release surface of the film using an applicator so that the thickness after drying was 20 μm and drying at 100 ° C. for 1 minute.

(3) Production of polarizing plate with pressure-sensitive adhesive layer Protective films made of the thermoplastic resin described in Table 3 on both surfaces of a 23 μm-thick polarizer in which iodine is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol film via an adhesive. A polarizing plate was produced by pasting. Next, the surface opposite to the separator (adhesive layer surface) in the pressure-sensitive adhesive layer prepared in (2) above was bonded to the outer surface of one protective film with a laminator, and then the temperature was 23 ° C. and the relative humidity was 65%. The plate was cured under conditions for 7 days to obtain a polarizing plate with an adhesive layer.

Abbreviations described in the column of “Protective film” in Table 3 mean the following thermoplastic resins.
AC: (meth) acrylic resin (contact angle change rate based on the above definition: 17.2%),
PE: polyester resin (contact angle change rate based on the above definition: 14.7%),
CE: Cellulosic resin (contact angle change rate based on the above definition: 21.7%).

(4) Durability Evaluation After peeling the separator from the polarizing plate with the pressure-sensitive adhesive layer produced in the above (3), the pressure-sensitive adhesive layer surface was applied to both surfaces of a glass substrate for liquid crystal cells [“Eagle XG” manufactured by Corning]. A sample for evaluation was prepared by sticking to cross Nicol. The following three types of durability tests were performed using this sample.
[Durability test]
・ Heat resistance test held at a temperature of 80 ° C. for 500 hours,
-Moisture and heat resistance test held for 500 hours in an environment of temperature 60 ° C and relative humidity 90%,
A heat shock resistance (HS) test in which an operation of holding for 30 minutes under a drying condition at a temperature of 70 ° C. and then holding for 30 minutes under a drying condition at a temperature of −40 ° C. is one cycle, and this is repeated 200 cycles.

  The sample after each test was visually observed, and durability was evaluated according to the following evaluation criteria. The results are shown in Table 3.

A: No change in appearance such as floating, peeling, foaming, etc.
B: Almost no change in appearance such as floating, peeling, foaming, etc.
C: Many appearance changes such as floating, peeling and foaming are observed.
D: Appearance changes such as floating, peeling and foaming are remarkably recognized.

(5) Evaluation of adhesion between protective film and pressure-sensitive adhesive layer A test piece having a width of 25 mm and a length of 150 mm was cut from the polarizing plate with the pressure-sensitive adhesive layer prepared in (3) above. Next, after peeling a separator from this test piece, it fixed to the adhesive force evaluation jig | tool made from Nippon System Group, and the next peeling test was implemented. A test rubber piece [material: neoprene rubber, hardness: JIS A hardness 65] is applied to the surface of the pressure-sensitive adhesive layer, and the rubber piece is reciprocated 20 times on the test piece to rub the surface of the pressure-sensitive adhesive layer with the rubber piece. It was. The moving direction of the test rubber piece and the width direction of the test piece were parallel.

  The surface on the pressure-sensitive adhesive layer side of the test piece after the peel test was observed. In any of the examples and comparative examples, the pressure-sensitive adhesive layer was peeled off at one end side in the width direction of the test piece after the peel test, and a part of the pressure-sensitive adhesive layer remained on the other end side. The position of the remaining pressure-sensitive adhesive layer (position in the length direction of the test piece) was determined, and the distance from the one end to the position was measured as the peel distance. The results are shown in Table 3. If peeling distance (curing period 7 days) is 15 mm or less, it can be said that the adhesiveness of a protective film and an adhesive layer is favorable.

  DESCRIPTION OF SYMBOLS 1 Polarizer, 2 Surface treatment layer, 3, 4 Protective film, 7 Retardation film, 8 Interlayer adhesive, 10 Polarizing plate, 20 Adhesive layer, 25 Adhesive layer attached polarizing plate, 30 Glass substrate.

Claims (10)

The content of the structural unit derived from the (meth) acrylic monomer having a hydroxyl group is 0.2 to 4% by weight, and the content of the structural unit derived from the (meth) acrylic monomer having a carboxyl group is 0. 100 parts by weight of (meth) acrylic resin (A) having a glass transition temperature of −55 ° C. or higher, and ˜4% by weight;
0.1 to 1 part by weight of an isocyanate-based crosslinking agent (B) in which an isocyanate group is bonded to a carbon atom constituting an aliphatic skeleton;
A pressure-sensitive adhesive composition comprising:   The pressure-sensitive adhesive composition according to claim 1, wherein the isocyanate group is bonded to a carbon atom constituting a methylene group.   The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the content of the structural unit derived from the (meth) acrylic monomer having a hydroxyl group is 3.5% by weight or less.   The pressure-sensitive adhesive composition according to any one of claims 1 to 3, further comprising an ionic compound (C).   The pressure-sensitive adhesive composition according to any one of claims 1 to 4, further comprising a silane compound (D).   The adhesive layer containing the adhesive composition of any one of Claims 1-5.   The optical member with an adhesive layer containing an optical member and the adhesive layer of Claim 6 laminated | stacked on it.   The optical member with an adhesive layer according to claim 7, wherein the surface of the optical member on which the adhesive layer is laminated has a contact angle change rate of 40% or less when corona treatment is performed. The optical member includes a polarizer and a protective film laminated thereon,
The said surface is an optical member with an adhesive layer of Claim 8 which is the surface of the said protective film.   The optical member with an adhesive layer according to claim 8 or 9, wherein the surface is a corona-treated surface.

Images