JP2010150400A - Adhesive composition and optical member using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition having excellent rework property, durability and light leakage property, and to provide an optical member. <P>SOLUTION: The adhesive composition contains a (meth)acrylic polymer (A) obtained by polymerizing (A1) >94 pts.mass to ≤98.9 pts.mass (meth)acrylate based monomer, (A2) ≥1 pts.mass to ≤5 pts.mass macro-monomer and (A3) ≥0.1 pts.mass to <1 pts.mass (meth)acrylate monomer containing at least one crosslinkable functional group selected from a group consisting of carboxyl, amino, amido, hydroxy, and acetoacetoxy groups, (where the total sum of (A1), (A2) and (A3) is 100 pts.mass) and a curing agent (B) having a functional group which reacts with the cross-linkable functional group, and has ≥55% to ≤80% gel fraction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an adhesive composition and an optical member using the same. More specifically, the present invention relates to an adhesive composition and an optical member that are excellent in reworkability, light leakage resistance, and durability.

  In recent years, the use of flat panel displays (FPD) such as liquid crystal display devices (LCD), plasma displays (PDP), and organic EL devices has been expanded. In these display devices, a method is used in which various optical members such as a polarizing plate, a retardation plate, and an antireflection film are adhered to a substrate with an adhesive.

  These display devices are installed in various portable devices, and the downsizing, thinning, and weight reduction of portable devices are being promoted. Adhesives used in such display devices are used in harsh environments and for long-term use. However, it is required that the adhesive strength can be maintained. In particular, there is a problem that defects such as foaming and peeling occur between the pressure-sensitive adhesive and the substrate in a high-temperature and high-humidity environment, and a pressure-sensitive adhesive having excellent durability even under high-temperature and high-humidity conditions is required. ing.

  On the other hand, when a defect such as mixing of foreign matter or positional deviation occurs when the optical member is bonded, it is necessary to peel the optical member from the base material and bond it again. When the optical member is peeled from the base material, reworkability (removability) that can easily peel the optical member from the substrate without causing damage such as a change in the gap of the liquid crystal cell or breakage of the substrate is required. . Moreover, when an adhesive is used for LCD, the characteristic (light leakage resistance) which prevents the light leakage by contraction of a polarizing plate is also calculated | required.

  As a method for improving the durability and reworkability of the pressure-sensitive adhesive, Patent Document 1 discloses (meth) acryloyl group-containing macromonomer 0.2 to 3 having a glass transition temperature of 40 ° C. or higher and a number average molecular weight of 2000 to 20000. Parts by weight, 57 to 98.8 parts by weight of alkyl (meth) acrylate, 1 to 20 parts by weight of a functional group-containing monomer, and 0 to 20 parts by weight of other monomers copolymerizable with at least the alkyl (meth) acrylate An adhesive using a copolymer (weight average molecular weight of 500,000 to 2,000,000) is disclosed.

Patent Document 2 discloses an acrylic copolymer (A) composed of a (meth) acryloyl group-containing macromonomer having a glass transition temperature of 40 ° C. or higher and a number average molecular weight of 2000 to 20000 and an acrylate monomer, and an epoxy group. The adhesive composition formed by mix | blending the silane type compound (B) which has a functional group which reacts with is disclosed.
Japanese Unexamined Patent Publication No. Hei 8-209090 JP-A-10-140122

  However, although the adhesive described in Patent Document 1 has improved durability under high-temperature and high-humidity conditions, it still has strong adhesive strength, and is bonded to a thin glass plate and peeled off (reworked). May be damaged. In addition, the pressure-sensitive adhesive composition described in Patent Document 2 also has good adhesiveness with respect to the micro uneven surface, and thus has high adhesive strength and insufficient rework characteristics. Furthermore, the adhesive described in Patent Document 1 and the pressure-sensitive adhesive composition described in Patent Document 2 have a problem of poor light leakage resistance.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a pressure-sensitive adhesive composition excellent in reworkability, light leakage resistance, and durability, particularly durability under high temperature and high humidity conditions. That is.

  As a result of intensive studies to solve the above problems, the present inventors have found that a pressure-sensitive adhesive composition containing a polymer having a predetermined composition and gel fraction and a curing agent has excellent reworkability, durability, And it discovered that light leakage resistance was expressed, and came to complete this invention.

That is, the problem of the present invention is that (A1) exceeds 94 parts by mass of the (meth) acrylate monomer and is 98.9 parts by mass or less, (A2) 1 to 5 parts by mass of the macromonomer, and (A3) carboxyl group Polymerizing 0.1 part by mass or more and less than 1 part by mass of a (meth) acrylate monomer containing at least one crosslinkable functional group selected from the group consisting of amino group, amide group, hydroxy group and acetoacetoxy group And (meth) acrylic polymer (A) [wherein the total amount of (A1), (A2) and (A3) is 100 parts by mass];
A curing agent (B) having a functional group that reacts with the crosslinkable functional group,
This is achieved by the pressure-sensitive adhesive composition having a gel fraction of 55% or more and 80% or less.

  The pressure-sensitive adhesive composition of the present invention is excellent in reworkability, light leakage resistance, and durability, particularly durability under high temperature and high humidity conditions. Therefore, the pressure-sensitive adhesive composition of the present invention is effective for adhesion of thin-layer adherends such as various plastic films, and particularly when used for a polarizing plate, obtains excellent reworkability, light leakage resistance, and durability. be able to.

  Embodiments of the present invention will be described below.

  The present invention comprises (A1) (meth) acrylate monomer exceeding 94 parts by mass and 98.9 parts by mass or less, (A2) macromonomer 1 part by mass to 5 parts by mass, and (A3) carboxyl group, amino group, A (meth) acrylate monomer containing at least one crosslinkable functional group selected from the group consisting of an amide group, a hydroxy group and an acetoacetoxy group is polymerized from 0.1 parts by weight to less than 1 part by weight (meth) Acrylic polymer (A) [however, the total amount of (A1), (A2) and (A3) is 100 parts by mass]; and curing agent (B) having a functional group that reacts with the crosslinkable functional group And the gel fraction is 55% or more and 80% or less.

  Hereinafter, each component of the pressure-sensitive adhesive composition of the present invention will be described in detail. In the present specification, “(meth) acrylate” is a general term for acrylate and methacrylate. Similarly, a compound containing (meth) such as (meth) acrylic acid is a general term for a compound having “meta” in the name and a compound not having “meta”.

(A) (Meth) acrylic polymer The (meth) acrylic polymer (A) used in the present invention (hereinafter also simply referred to as “component (A)”) is (A1) a (meth) acrylate monomer, (A2 ) Macromonomer and (A3) a crosslinkable functional group-containing (meth) acrylate monomer.

(A1) (Meth) acrylate monomer (Meth) acrylate monomer (hereinafter also simply referred to as “component (A1)”) is an ester of (meth) acrylic acid having no crosslinkable functional group in the molecule. . Specific examples of the component (A1) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth). Acrylate, tert-butyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, tert-octyl (meth) acrylate, 2- Ethylhexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, phenyl (meth) acrylate Benzyl (meth) acrylate, dodecyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, cyclohexyl (meth) acrylate, 4-n-butylcyclohexyl (meth) acrylate, 2-ethylhexyl diglycol (meth) acrylate, butoxyethyl ( (Meth) acrylate, butoxymethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2- (2-methoxyethoxy) ethyl (meth) acrylate, 2- (2-butoxyethoxy) ethyl (meth) acrylate, 4- Butylphenyl (meth) acrylate, phenyl (meth) acrylate, 2,4,5-tetramethylphenyl (meth) acrylate, phenoxymethyl (meth) acrylate, phenoxyethyl (meth) acrylate Polyethylene oxide monoalkyl ether (meth) acrylate, polyethylene oxide monoalkyl ether (meth) acrylate, polypropylene oxide monoalkyl ether (meth) acrylate, trifluoroethyl (meth) acrylate, pentadecafluorooxyethyl (meth) acrylate, 2- Examples include chloroethyl (meth) acrylate, 2,3-dibromopropyl (meth) acrylate, and tribromophenyl (meth) acrylate. These components (A1) may be used alone or in combination of two or more.

  Among these components (A1), methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and tert-butyl (meth) acrylate are preferable, methyl acrylate, ethyl acrylate, n-Butyl acrylate is more preferable, and methyl acrylate and n-butyl acrylate are particularly preferable.

  Component (A1) is used in an amount of 98.9 parts by mass, more than 94 parts by mass, and 95.2 parts by mass or more, 98.5 parts by mass, with the total amount of components (A1) to (A3) being 100 parts by mass. The amount is preferably not more than part by mass, more preferably not less than 96.3 parts by mass and not more than 97.7 parts by mass. Within such a range, good adhesiveness and heat resistance are exhibited.

(A2) Macromonomer A macromonomer is a high molecular weight monomer having a polymerizable functional group (polymerizable group) and comprises a polymer chain portion and a polymerizable group portion.

  The polymerizable group of the macromonomer reacts with the (A1) (meth) acrylate monomer or (A3) the crosslinkable functional group-containing (meth) acrylic monomer to form a main chain structure in the (meth) acrylic polymer (A). The polymer chain portion of the macromonomer forms a side chain grafted to the main chain of the (meth) acrylic polymer (A). This side chain forms a micro domain (discontinuous phase) in the pressure-sensitive adhesive composition of the present invention, and acts as a highly agglomerated component. For this reason, the pressure sensitive adhesive composition of the present invention has a good cohesive force even in a structure where the density of crosslinking by a crosslinking agent or the like is low, and is excellent in stress relaxation after low-speed deformation, and therefore, light leakage resistance, Reworkability and durability are improved.

  As the polymerizable group, a group having an ethylenically unsaturated double bond (ethylenically unsaturated group) is preferable. Specifically, it is preferably at least one selected from the group consisting of a vinyl group, an allyl group, a (meth) acryloyl group, a propenyl group, a vinylidene group, and a vinylene group, and more preferably a (meth) acryloyl group. . The polymerizable group is preferably present at the end of the macromonomer, and more preferably present only at one end of the macromonomer from the viewpoint of stability during polymerization. However, the polymerizable group may exist as a side chain of the macromonomer, or may exist at both ends of the macromonomer chain.

  The polymer chain portion constituting the macromonomer is methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, styrene, acrylonitrile, etc. A (co) polymer having a repeating unit derived from a main structural unit is preferred. These polymer chain portions may be composed of a single repeating unit, or may be composed of a plurality of repeating units. Further, when the polymer chain is a copolymer composed of a plurality of repeating units, the repeating form is not limited, and any of an alternating copolymer, a random copolymer, and a block copolymer may be used.

  Preferable examples of the macromonomer include monomers represented by the following formula (I).

However, in the formula (I), ^{R 1} represents a hydrogen atom or a methyl group. X represents a single bond or a divalent linking group. Y is one or two selected from methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, styrene, acrylonitrile A polymer chain obtained by homopolymerizing or copolymerizing the above monomers is represented. Among these, a polymer chain formed by homopolymerizing methyl methacrylate and styrene, and a polymer chain formed by copolymerizing acrylonitrile and styrene are preferably used.

  Examples of the divalent linking group include a linear, branched or cyclic alkylene group, an aralkylene group, and an arylene group. These may further have a substituent such as a hydroxy group or a cyano group. As carbon number of the said alkylene group, 1-10 are preferable and 1-4 are more preferable. Examples of the alkylene group include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, an octylene group, and a decylene group. Among these, a methylene group, an ethylene group, a propylene group, and the like are preferable. As carbon number of the said aralkylene group, 7-13 are preferable. Examples of the aralkylene group include a benzylidene group and a cinnamylidene group. As carbon number of the said arylene group, 6-12 are preferable. Examples of the arylene group include a phenylene group, a cumenylene group, a mesitylene group, a tolylene group, and a xylylene group. Among these, a phenylene group is preferable.

In the divalent linking group, —NR ² —, —COO—, —OCO—, —O—, —S—, —SO ₂ NH—, —NHSO ₂ —, —NHCOO—, —OCONH are further included. -Or a group derived from a heterocyclic ring, or the like may be interposed as a linking group. R ² is hydrogen or an alkyl group such as a methyl group, an ethyl group, or a propyl group.

  The number average molecular weight (Mn) of the macromonomer is preferably in the range of 2000 to 20000, more preferably in the range of 2000 to 10000, and still more preferably in the range of 4000 to 8000. If the number average molecular weight (Mn) is 2000 or more, sufficient adhesive strength can be secured and heat resistance is excellent. On the other hand, if it is 20000 or less, the fall of workability | operativity by the raise of the viscosity of an adhesive composition can be suppressed. The value of the number average molecular weight (Mn) can be controlled by appropriately selecting the amounts of a chain transfer agent and a polymerization initiator added to the polymerization system. In addition, in this invention, the value of polystyrene conversion measured by GPC (gel permeation chromatography) method shall be employ | adopted for the number average molecular weight (Mn) of a macromonomer.

  The glass transition temperature (Tg) of the macromonomer is preferably 40 ° C to 150 ° C, more preferably 60 to 140 ° C, and further preferably 80 to 130 ° C. The cohesive force (physical crosslinking effect) due to the microdomain of the macromonomer is expressed in a temperature region below the glass transition temperature of the macromonomer, and the cohesive force is reduced in an environment near the glass transition temperature. Therefore, the glass transition temperature (Tg) is preferably 40 ° C. or higher from the viewpoint of securing a sufficient cohesive force. On the other hand, if it is 150 degrees C or less, since the fall of tack property and adhesive force can be suppressed, it is preferable.

  The method for producing such a macromonomer is not particularly limited. For example, (1) a method of producing a polymer chain (living polymer anion) constituting a macromonomer by living anion polymerization and allowing methacrylic acid chloride or the like to act on the polymer chain ; (2) In the presence of a chain transfer agent such as mercaptoacetic acid, a radical polymerizable monomer such as methyl methacrylate is polymerized to obtain an oligomer having a carboxyl group at the terminal, and then this is reacted with glycidyl methacrylate or the like. Method: (3) In the presence of an azo polymerization initiator containing a carboxyl group, a radical polymerizable monomer such as methyl methacrylate is polymerized to obtain an oligomer having a carboxyl group at the terminal, and then converted into a macromonomer with glycidyl methacrylate. Any method can be used such as

  By producing a macromonomer using the method as described above, for example, the following groups are introduced as the divalent linking group represented by X in the above formula (I).

  A commercial item can also be used as said macromonomer. For example, a macromonomer (product name: 45% AA-6 (AA-6S), AA-6; manufactured by Toagosei Co., Ltd.) in which the terminal is a methacryloyl group and the segment is methyl methacrylate (MMA), and the segment is styrene Macromonomer (product name: AS-6S, AS-6; manufactured by Toagosei Co., Ltd.), macromonomer whose segment is a copolymer of styrene / acrylonitrile (product name: AN-6S; manufactured by Toagosei Co., Ltd.) ), A macromonomer having a butyl acrylate segment (product name: AB-6; manufactured by Toagosei Co., Ltd.) and the like.

  Among these components (A2), a (co) polymer (product name: 45% AA-6 (AA-6S), AA-6; Toago) having a repeating unit derived from methyl methacrylate (MMA) as a main constituent unit Synthetic Co., Ltd.) is particularly preferred because of its good compatibility. In addition, these macromonomers may be used independently and may be used together 2 or more types.

  The amount of component (A2) used is from 1 to 5 parts by weight, and from 1.3 to 4.0 parts by weight, with the total amount of components (A1) to (A3) being 100 parts by weight. It is preferable that it is 2.0 parts by mass or more and 3.0 parts by mass or less. By setting it as such a range, it becomes possible to make the cohesiveness of a (meth) acrylic-type polymer into a preferable state. If the amount is less than 1 part by mass, sufficient cohesive force cannot be obtained, and the reworkability may be reduced. On the other hand, when it exceeds 5 parts by mass, the cohesive force becomes too high and the adhesive force may be lowered, and the stress relaxation property may be lowered, and the light leakage resistance may be lowered.

(A3) Crosslinkable functional group-containing (meth) acrylic monomer Crosslinkable functional group-containing (meth) acrylic monomer (hereinafter also simply referred to as “component (A3)”) is an acrylic having a crosslinkable functional group in the molecule. Monomer. A crosslinkable structure is introduced into the (meth) acrylic polymer (A) by the reaction and bonding of the crosslinkable functional group of the component (A3) with the curing agent (B) described later.

  The crosslinkable functional group is at least one of a carboxyl group, an amino group, an amide group, a hydroxy group, and an acetoacetyl group, preferably at least one of a carboxyl group and a hydroxy group, and more preferably a hydroxy group.

  Specific examples of the component (A3) include (meth) acrylic acid, 2-methacryloyloxysuccinic acid, 2-methacryloyloxyethylmaleic acid, 2-methacryloyloxyethylphthalic acid, and 2-methacryloyloxyethylhexahydrophthalic acid. Carboxyl group-containing (meth) acrylic monomers such as monomethylaminoethyl (meth) acrylate, monoethylaminoethyl (meth) acrylate, monomethylaminopropyl (meth) acrylate, monoethylaminoprotyl (meth) acrylate, dimethylaminoethyl (Meth) acrylate, diethylaminoethyl (meth) acrylate, N-tert-butylaminoethyl (meth) acrylate, methacryloxyethyltrimethylammonium chloride (meth) acrylate Amino group-containing (meth) acrylic monomers: (meth) acrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N, N-methylenebis ( Amide group-containing (meth) acrylic monomers such as (meth) acrylamide and 2-hydroxyethylacrylamide; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3- Hydroxypropyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 1,6-hexanediol mono (meth) acrylate, pentaerythritol tri (meth) a Relate, dipentaerythritol penta (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolethane di (meth) acrylate, trimethylolpropane di (meth) acrylate, 2-hydroxy-3-phenyloxypropyl (meth) Hydroxy group-containing (meth) acrylic monomers such as acrylate, 4-hydroxycyclohexyl (meth) acrylate, and cyclohexanedimethanol mono (meth) acrylate; Acetacetoxy group-containing (meth) acrylic such as 2-acetoacetoxyethyl (meth) acrylate System monomers and the like. Furthermore, a compound obtained by an addition reaction between a glycidyl group-containing compound such as alkyl glycidyl ether, allyl glycidyl ether, or glycidyl (meth) acrylate and (meth) acrylic acid may be used. These components (A3) may be used alone or in combination of two or more.

  Among these components (A3), cyclohexanedimethanol mono (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, (meth) acrylic acid, 2-hydroxyethylacrylamide, 2- Acetoacetoxyethyl (meth) acrylate is preferred, cyclohexanedimethanol mono (meth) acrylate, 2-hydroxyethyl (meth) acrylate and 2-hydroxyethylacrylamide are more preferred, and cyclohexanedimethanol mono (meth) acrylate is particularly preferred.

  The amount of the component (A3) used is 0.1 parts by mass or more and less than 1 part by mass, preferably 0.2 parts by mass or more and 0.8 parts by mass, with the total amount of the components (A1) to (A3) being 100 parts by mass. It is not more than part by mass, and more preferably not less than 0.3 part by mass and not more than 0.7 part by mass. If the amount is less than 0.1 parts by mass, the amount of crosslinking due to a crosslinking reaction with a curing agent described later is small, which may lead to deterioration in durability and deterioration in reworkability due to reduction in cohesive force. On the other hand, when the amount is 1 part by mass or more, the stress relaxation property is lowered due to the high crosslinking, and the light leakage resistance may be lowered.

  As described above, in the pressure-sensitive adhesive composition of the present invention, (A2) a high cohesive force is expressed by the microdomain structure formed from the side chain derived from the macromonomer, so the amount of the component (A3) used is within the above range. Thus, even if it is a case where it is a small amount compared to the conventional case and low cross-linking, it has a high cohesive force. Therefore, the pressure-sensitive adhesive composition of the present invention can exhibit excellent durability, reworkability, and light leakage resistance.

  The production method of the (meth) acrylic polymer (A) is not particularly limited, and is a solution polymerization method using a polymerization initiator, an emulsion polymerization method, a suspension polymerization method, a reverse phase suspension polymerization method, a thin film polymerization method, a spray. A conventionally known method such as a polymerization method can be used. Examples of the polymerization control method include adiabatic polymerization, temperature controlled polymerization, and isothermal polymerization. In addition to the method of initiating polymerization with a polymerization initiator, a method of initiating polymerization by irradiating with radiation, electron beam, ultraviolet rays or the like can also be employed. Among these, the solution polymerization method using a polymerization initiator is preferable because the molecular weight can be easily adjusted and impurities can be reduced. For example, ethyl acetate, toluene, methyl ethyl ketone or the like is used as a solvent, and the polymerization initiator is preferably 0.01 parts by mass or more and 0.50 parts by mass or less with respect to 100 parts by mass of the total amount of components (A1) to (A3). For example, at a reaction temperature of 60 to 90 ° C. for 3 to 10 hours. Examples of the polymerization initiator include azo compounds such as azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), azobiscyanovaleric acid; tert-butyl peroxypivalate, tert-butyl. Organic peroxides such as peroxybenzoate, tert-butylperoxy-2-ethylhexanoate, di-tert-butyl peroxide, cumene hydroperoxide, benzoyl peroxide, tert-butyl hydroperoxide; hydrogen peroxide And inorganic peroxides such as ammonium persulfate, potassium persulfate, and sodium persulfate. These may be used alone or in combination of two or more.

  The (meth) acrylic polymer (A) obtained by copolymerizing the components (A1) to (A3) preferably has a weight average molecular weight (Mw) of 700,000 to 2,000,000, preferably 900,000 to 160. More preferably, it is 10,000. If the weight average molecular weight is less than 700,000, heat resistance may be insufficient. On the other hand, when the weight average molecular weight exceeds 2 million, the tack is low and the bonding property may be lowered. In addition, in this invention, the value of polystyrene conversion measured by the method as described in an Example shall be employ | adopted for the weight average molecular weight of (meth) acrylic-type polymer (A). Moreover, there is no restriction | limiting in particular about the copolymerization form of (meth) acrylic-type polymer (A), Any of a random and a block may be sufficient.

  The component (A) may be used alone or in combination of two or more polymers.

(B) Curing Agent In addition to the component (A), the pressure-sensitive adhesive composition of the present invention has a functional group that reacts with the crosslinkable functional group of the crosslinkable functional group-containing (meth) acrylate monomer (A3). Agent (B) (hereinafter, also simply referred to as “component (B)”). The curing agent (B) reacts and bonds with a crosslinkable functional group derived from the component (A3) in the (meth) acrylic polymer (A) to form a crosslinked structure.

  As such a curing agent (B), for example, when the crosslinkable functional group in the crosslinkable functional group-containing (meth) acrylate monomer (A3) is a carboxyl group, an epoxy group-containing compound or an isocyanate group-containing compound is When the crosslinkable functional group is a hydroxy group, an isocyanate group-containing compound, an amino group-containing compound, or a formyl group-containing compound is used. When the crosslinkable functional group is an amino group or an amide group, an epoxy group-containing compound is used. When the group is an acetoacetoxy group, an isocyanate group-containing compound and an amino group-containing compound are each preferably used. Specific examples include isocyanate curing agents, epoxy curing agents, melamine curing agents, urea curing agents, dialdehyde curing agents, metal chelate compounds, metal alkoxides, and metal salts. Among them, in particular, when the crosslinkable functional group in the crosslinkable functional group-containing (meth) acrylate monomer (A3) is a hydroxyl group or a carboxyl group, the curing agent (B) is an isocyanate-based curing agent that is an isocyanate group-containing compound. A combination is preferable in terms of tackiness (initial adhesive strength) and heat resistance.

  The isocyanate curing agent is not particularly limited. Specifically, for example, triallyl isocyanate, dimer acid diisocyanate, 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), 4,4′- Diphenylmethane diisocyanate (4,4′-MDI), 2,4′-diphenylmethane diisocyanate (2,4′-MDI), 1,4-phenylene diisocyanate, xylylene diisocyanate (XDI), tetramethylxylidene diisocyanate (TMXDI), Aromatic diisocyanates such as tolidine diisocyanate (TODI) and 1,5-naphthalene diisocyanate (NDI); hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate Aliphatic diisocyanates such as norbornane diisocyanate methyl (NBDI); transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), H6-XDI (hydrogenated XDI), H12-MDI (hydrogenated MDI), etc. Alicyclic diisocyanates; carbodiimide-modified diisocyanates of the above-mentioned diisocyanates; or these isocyanurate-modified diisocyanates. Moreover, the adduct body of the said isocyanate compound and polyol compounds, such as a trimethylol propane, the biuret body and isocyanurate body of these isocyanate compounds can also be used conveniently.

  The isocyanate curing agent may be synthesized or a commercially available product may be used. Examples of commercially available isocyanate curing agents include Coronate L (trimethylolpropane / tolylene diisocyanate trimer adduct), Coronate HL (trimethylolpropane / hexamethylene diisocyanate trimer adduct), and Coronate HX (hexa). Isocyanurate of methylene diisocyanate), coronate 2030, coronate 2031 (manufactured by Nippon Polyurethane Industry Co., Ltd.), Takenate (registered trademark) D-102, Takenate (registered trademark) D-110N, takenate (registered trademark) D-200 Takenate (registered trademark) D-202 (manufactured by Mitsui Chemicals Polyurethane Co., Ltd.), Duranate (trademark) 24A-100, Duranate (trademark) TPA-100, Duranate (trademark) TKA-100, Duranate (trademark) P301-75E, Duranate (trademark) E402-90T, Duranate (trademark) E405-80T, Duranate (trademark) TSE-100, Duranate (trademark) D-101, Duranate (trademark) D-201 (above, Asahi Kasei Chemicals Corporation Manufactured) and the like.

  Among these isocyanate curing agents, Coronate L, Coronate HL, Takenate (registered trademark) D110N, and Duranate (trademark) 24A-100 are preferable, Coronate L and Takenate (registered trademark) D110N are more preferable, and Coronate L is particularly preferable.

  In addition, a hardening | curing agent (B) may be used individually by 1 type, and may be used in combination of 2 or more type.

  In this invention, it is preferable that the compounding quantity of a component (B) is 0.05 to 5 mass parts with respect to 100 mass parts of components (A). If it is 0.05 part by mass or more, cohesive force and heat resistance can be obtained by introducing a crosslinking point formed by a reaction between the crosslinkable functional group derived from the component (A3) in the polymer (A) and the curing agent (B). Can be improved. On the other hand, if it is 5 parts by mass or less, such crosslinking points do not become excessive, and the pressure-sensitive adhesive composition of the present invention can have excellent reworkability and flexibility. The blending amount is more preferably 0.05 parts by mass or more and 1 part by mass or less, and still more preferably 0.05 parts by mass or more and 0.7 parts by mass or less.

(C) Other components In addition to the said component (A) and (B), the adhesive composition of this invention may also contain a silane coupling agent. By using a silane coupling agent, the reactivity can be improved and the mechanical strength and adhesive strength of the cured product can be improved. Such a silane coupling agent is not particularly limited. Specifically, for example, methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, n-propyltrimethoxysilane, ethyltrimethoxysilane, diethyldiethoxysilane, n-butyltrimethoxysilane, n-hexyltriethoxysilane , N-octyltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, cyclohexylmethyldimethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3 4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropylme Tildimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-acryloxypropyltrimethoxysilane, N-β- (aminoethyl)- γ-aminopropylmethyldimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis- (3- [ bird Tokishishiriru] propyl) tetrasulfide, .gamma. isocyanatepropyltriethoxysilane and the like. Further, a silane coupling agent having a functional group such as an epoxy group (glycidoxy group), an amino group, a mercapto group, or a (meth) acryloyl group, and a functional group having reactivity with these functional groups. A compound having a hydrolyzable silyl group obtained by reacting an agent, another coupling agent, polyisocyanate and the like with each functional group in an arbitrary ratio can also be used.

  The silane coupling agent may be synthesized or a commercially available product may be used. Examples of commercially available silane coupling agents include KBM-303, KBM-403, KBE-402, KBM-403, KBE-502, KBE-503, KBM-5103, KBM-573, KBM-802, and KBM-. 803, KBE-846, KBE-9007 (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like.

  Among these silane coupling agents, KBM-303, KBM-403, KBE-402, KBM-403, KBM-5103, KBM-573, KBM-802, KBM-803, KBE-846, and KBE-9007 are preferable. KBM-403 is more preferred. In addition, the said silane coupling agent may be used independently and may be used in combination of 2 or more types.

  In the present invention, the amount of the silane coupling agent used is not particularly limited. Specifically, the amount of the silane coupling agent is preferably 0.01 parts by mass or more and 5 parts by mass or less, more preferably 100 parts by mass of the total amount of the components (A) to (C). It is 0.03 mass part or more and 2 mass parts or less, More preferably, it is 0.05 mass part or more and 0.5 mass part or less. If it exists in this range, the outstanding heat resistance and adhesiveness can be exhibited. When the compounding amount of the silane coupling agent is less than 0.01 parts by mass, the glass adhesiveness may be lowered. On the other hand, when it exceeds 5 mass parts, heat resistance may fall.

  In addition to or in place of the silane coupling agent, the pressure-sensitive adhesive composition of the present invention comprises a curing accelerator, an ionic liquid, an inorganic filler, a softening agent, an antioxidant, an anti-aging agent, Stabilizer, tackifying resin, modifying resin (polyol resin, phenol resin, acrylic resin, polyester resin, polyolefin resin, epoxy resin, epoxidized polybutadiene resin, etc.), leveling agent, antifoaming agent, plasticizer, dye, pigment ( Including additives such as color pigments, extender pigments, treatment agents, UV blockers, fluorescent brighteners, dispersants, heat stabilizers, light stabilizers, UV absorbers, antistatic agents, lubricants and solvents. Good. Examples of the ionic liquid include phosphonium ion, pyridinium ion, pyrrolidinium ion, imidazolium ion, guanidinium ion, ammonium ion, isouronium ion, thiouronium ion, piperidinium ion, pyrazolium ion, sulfonium ion and the like. As cation component and anion component, halogen ion, nitrate ion, sulfate ion, phosphate ion, perchlorate ion, thiocyanate ion, thiosulfate ion, sulfite ion, tetrafluoroborate ion, hexafluorophosphate ion, formate ion, And substances having an anion component such as oxalate ion, acetate ion, trifluoroacetate ion, and alkylsulfonate ion. Examples of the antioxidant include dibutylhydroxytoluene (BHT), Irganox (registered trademark) 1010, Irganox (registered trademark) 1035FF, Irganox (registered trademark) 565 (all manufactured by Ciba Specialty Chemicals) and the like. Can be mentioned. Examples of the tackifying resin include rosins such as rosin acid, polymerized rosin acid and rosin acid ester, terpene resin, terpene phenol resin, aromatic hydrocarbon resin, aliphatic saturated hydrocarbon resin and petroleum resin. Examples of the ultraviolet absorber include benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, benzoate ultraviolet absorbers, and triazine ultraviolet absorbers. Although the usage-amount of an additive in the case of using the said additive is not restrict | limited in particular, For example, 0.1 mass part or more and 20 mass with respect to 100 mass parts of total amounts of the said component (A) and (B) Or less.

  The pressure-sensitive adhesive composition of the present invention can be prepared by mixing the above-described components all together, mixing each component sequentially, or mixing any plural components and then mixing the remaining components. It can manufacture by stirring so that it may become a uniform mixture. More specifically, it can be prepared by heating, for example, to a temperature of 30 to 40 ° C. as necessary, and stirring for 10 minutes to 5 hours until it becomes uniform with a stirrer or the like.

  The gel fraction of the pressure-sensitive adhesive composition of the present invention is 55% or more and 80% or less, preferably 60% or more and 75% or less, and more preferably 65% by mass or more and 75% or less. When the gel fraction is less than 55%, the cohesive force of the pressure-sensitive adhesive composition is insufficient, and reworkability and durability may be inferior. If it exceeds 80%, the cohesive force of the pressure-sensitive adhesive increases, but the flexibility and tackiness may decrease, or the stress relaxation property may decrease and the light leakage may be inferior. The gel fraction adjusts the composition ratio of (A) (meth) acrylate polymer, especially (A3) the amount of crosslinkable functional group (meth) acrylate monomer used, (B) the amount of curing agent used, and the curing accelerator. By doing so, the above range can be adjusted. In addition, in this invention, the value measured by the method as described in an Example shall be employ | adopted for a gel fraction.

  The viscosity of the pressure-sensitive adhesive composition of the present invention is not particularly limited. However, considering the ease of coating and the like, the viscosity at 25 ° C. is preferably 0.5 to 8.0 Pa · s, more preferably 1.0 to 5.0 Pa · s. If the viscosity is less than 0.5 Pa · s, there may be a case where the coating surface is crushed. On the other hand, if it exceeds 8.0 Pa · s, coating streaks may occur.

  The pressure-sensitive adhesive composition of the present invention preferably has an adhesive strength to glass of 2.0 to 8.0 N / 25 mm, more preferably 3.0 to 7.0 N / 25 mm, and 4.0 to 4.0. More preferably, it is 6.0 N / 25 mm. If it is 2.0 N / 25mm or more, the adhesive force required for bonding of adherends, such as a polarizing plate, will be fully obtained. If it is 8.0 N / 25 mm or less, there is little adhesive residue and it is excellent in reworkability. In addition, in this invention, the adhesive force shall employ | adopt the value measured by the method as described in an Example based on JISZ0237.

  The pressure-sensitive adhesive composition of the present invention can be used for bonding various substrates. Examples of the substrate that can be used here include glass, plastic film, paper, and metal foil. Examples of the glass include general inorganic glass. Examples of the plastic in the plastic film include polyvinyl chloride resin, polyvinylidene chloride, cellulose resin, acrylic resin, cycloolefin resin, amorphous polyolefin resin, polyethylene, polypropylene, polystyrene, ABS resin, polyamide, and polyester. , Polycarbonate, polyurethane, polyvinyl alcohol, ethylene-vinyl acetate copolymer and chlorinated polypropylene. The amorphous polyolefin-based resin usually has a polymerization unit of a cyclic polyolefin such as norbornene or a polycyclic norbornene-based monomer, and may be a copolymer of a cyclic olefin and a chain cyclic olefin. Commercially available non-crystalline polyolefin resins such as Arton from JSR Corporation, ZEONEX (registered trademark) from ZEON Corporation, ZEONOR (registered trademark), APO from Mitsui Chemicals, Apel (registered trademark), etc. There is. In order to form an amorphous polyolefin-based resin into a film, a known method such as a solvent casting method or a melt extrusion method is appropriately used. Examples of the paper include imitation paper, fine paper, craft paper, art coat paper, caster coat paper, pure white roll paper, parchment paper, water resistant paper, glassine paper, and corrugated paper. Examples of the metal foil include aluminum foil.

  Therefore, this invention also provides an optical member provided with the adhesive layer formed from the adhesive composition of this invention.

  Preferred examples of the optical member include a polarizing plate, a retardation plate, an optical film for plasma display, and a conductive film for touch panel. Among these, the adhesive composition of this invention is excellent in the adhesiveness of a polarizing plate and glass. Of course, the present invention is not limited to the above-described form, and can be used for bonding other members.

  The pressure-sensitive adhesive composition of the present invention may be used by directly applying to one or both sides of an optical film to form a pressure-sensitive adhesive layer, or by previously forming a pressure-sensitive adhesive layer on a release film. It may be used by transferring to one side or both sides.

  Coating of the pressure-sensitive adhesive composition of the present invention may be performed by a conventionally known method, for example, natural coater, knife belt coater, floating knife, knife over roll, knife on blanket, spray, dip, kiss roll, squeeze roll, Various coating methods using apparatuses such as a reverse roll, an air blade, a curtain flow coater, a doctor blade, a wire bar, a die coater, a comma coater, a baker applicator, and a gravure coater may be mentioned. Moreover, what is necessary is just to select the application | coating thickness (thickness after drying) of the composition of this invention according to the base material to be used and a use, Preferably it is 5-40 micrometers, More preferably, it is 15-30 micrometers. is there.

  The pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive composition of the present invention is obtained by crosslinking the pressure-sensitive adhesive composition as described above. At that time, the pressure-sensitive adhesive composition is generally crosslinked after application of the pressure-sensitive adhesive composition, but it is also possible to transfer a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition after crosslinking to a substrate or the like. is there. Crosslinking of this pressure-sensitive adhesive composition is usually carried out by allowing it to stand under conditions of a temperature of 20 to 40 ° C., a relative humidity of 30 to 70% RH, and normal pressure (atmospheric pressure).

  The pressure-sensitive adhesive composition of the present invention exhibits excellent flexibility, thereby exhibiting excellent reworkability (removability) and processability. For example, even if a positional deviation between the optical film and the adherend occurs in the bonding step of the optical member, the optical film can be peeled without any adhesive remaining on the adherend. In particular, when used for a polarizing plate, excellent light leakage resistance and reworkability can be obtained.

  In addition, since the pressure-sensitive adhesive composition of the present invention has excellent heat resistance, it can exhibit high durability that does not float or peel off by heat treatment or high-humidity treatment.

  The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples.

  In addition, the solid content and the viscosity of the solution in which the methacrylic polymer (A) is dissolved were measured by the following method.

(Solid content)
About 1 g of the polymer solution is precisely weighed in a precisely weighed glass dish. After drying at 105 ° C. for 1 hour, the temperature is returned to room temperature, and the total mass of the glass dish and the remaining solid is precisely weighed. The solid content was calculated by the following formula 1, where X is the mass of the glass plate, Y is the total mass of the glass plate before drying and the polymer solution, and Z is the total mass Z of the glass plate and the remaining solid content.

(viscosity)
The pressure-sensitive adhesive solution contained in the glass bottle was temperature-controlled at 25 ° C. and measured with a B-type viscometer.

(Gel fraction)
About 0.1 g of the pressure-sensitive adhesive composition was weighed to obtain a weight W ₁ (g). This was collected in a sample bottle, and about 30 g of ethyl acetate was added and left for 24 hours. The contents of the sample bottle after a lapse of a predetermined time are separated by a 200 mesh stainless steel wire mesh (the weight of the wire mesh is W ₂ (g)), and the wire mesh and the residue are dried at 90 ° C. for 1 hour. ₃ (g) was measured. Under the present circumstances, the gel fraction was computed by following Numerical formula 2 from these measured values.

(Weight average molecular weight and number average molecular weight)
The measurement was performed according to the measurement method and measurement conditions shown in Table 1 below.

[Example 1]
A 45% toluene solution of a macromonomer in which 98.5 parts by mass of n-butyl acrylate (manufactured by Nippon Shokubai Co., Ltd.), one end is a methacryloyl group and a segment is methyl methacrylate (MMA) is placed in a container equipped with a reflux and a stirrer. Mn = 6000, trade name: AA-6S, manufactured by Toa Gosei Chemical Co., Ltd.) equivalent to 1 part by mass as solid content, cyclohexanedimethanol monoacrylate (CHDMAA) (manufactured by Nippon Kasei Co., Ltd.) 0.5 part by mass, and acetic acid 130 parts by mass of ethyl was charged. Next, the mixture was heated to 65 ° C. while performing nitrogen substitution, 0.075 parts by mass of azobisisobutyronitrile (AIBN) was added, and polymerization was performed for 6 hours while maintaining 65 ° C. After completion of the polymerization reaction, 270 parts by mass of ethyl acetate was added for dilution to obtain a solution of the methacrylic polymer (A). The obtained polymer solution had a solid content of 19.0% by mass and a viscosity of 5.0 Pa · s. Moreover, the weight average molecular weight of the obtained methacrylic polymer (A) was 1.3 million.

  Next, to the polymer solution obtained above, coronate L (trimethylolpropane / tolylene diisocyanate trimer) which is an isocyanate curing agent which is a curing agent (B) with respect to 100 parts by mass of the methacrylic polymer (A). 0.2 parts by mass of an adduct (manufactured by Nippon Polyurethane Industry Co., Ltd.) and 0.2 of glycidoxypropylmethyldiethoxysilane (trade name: KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.) which is a silane coupling agent These were added so that it might become a mass part, and it mixed for 15 minutes at 25 degreeC, and obtained the solution of the adhesive composition (1).

  This solution is applied onto a peeled PET film (Mitsubishi Chemical Polyester Film Co., Ltd., MRF38, thickness: 38 μm) using a baker applicator so that the thickness after drying is 25 μm, and bonded to a polarizing plate. did. Thereafter, the film was aged for 7 days under conditions of 23 ° C./45% RH to obtain a polarizing plate (1).

[Examples 2 and 3]
Except for using the acrylate polymer (A) components (A1) to (A3), the curing agent (B), and the silane coupling agent in the composition as shown in Table 2 below, the same as in Example 1 The pressure-sensitive adhesive compositions (2) and (3) were prepared.

  Next, in Example 1, instead of the pressure-sensitive adhesive composition (1), in the same manner as in Example 1 except that each of the pressure-sensitive adhesive compositions (2) and (3) prepared above was used. Plates (2) to (3) were obtained.

  The polarizing plates (2) and (3) thus obtained were evaluated for heat resistance, moist heat resistance, light leakage, and reworkability according to the following methods. The results are shown in Table 2 below.

[Comparative Examples 1 and 2]
Except for using the acrylate polymer (A) components (A1) to (A3), the curing agent (B), and the silane coupling agent in the composition as shown in Table 2 below, the same as in Example 1 Comparative adhesive compositions (1) and (2) were prepared.

  Next, in Example 1, instead of the adhesive composition (1), the comparative adhesive compositions (1) and (2) prepared above were used in the same manner as in Example 1, except that Comparative polarizing plates (1) and (2) were obtained.

  The comparative polarizing plates (1) and (2) thus obtained were evaluated for heat resistance, moist heat resistance, light leakage, and reworkability according to the following methods. The results are shown in Table 2 below.

[Evaluation]
(Heat resistance test)
A sample cut into 120 mm (polarizing plate MD direction) × 60 mm from the polarizing plate produced in each example and each comparative example was bonded to a glass plate, and the temperature was 50 ° C. and the pressure was 5 kg / cm ² for 20 minutes. Autoclave treatment was performed. Thereafter, the sample was allowed to stand at a temperature of 80 ° C. for 120 hours, and the state of the sample after being left was observed. In Table 2 below, “good” means that there is no peeling at the film edge, and “peeling” means that there is peeling at the film edge.

(Moisture and heat resistance test)
A sample cut into 120 mm (polarizing plate MD direction) × 60 mm from the polarizing plate produced in each example and each comparative example was bonded to a glass plate, and the temperature was 50 ° C. and the pressure was 5 kg / cm ² for 20 minutes. Autoclave treatment was performed. Thereafter, the sample was allowed to stand for 120 hours at a temperature of 60 ° C. and a humidity of 90% RH, and the state of the sample after being left was observed. In Table 2 below, “good” means that there is no peeling at the film edge, and “peeling” means that there is peeling at the film edge.

(Light leakage resistance test)
Samples cut into 120 mm (polarizing plate MD direction) × 60 mm and 120 mm (polarizing plate TD direction) × 60 mm from the polarizing plates produced in each example and each comparative example were bonded so as to overlap each surface of the glass plate. Then, autoclaving was performed for 20 minutes under the conditions of a temperature of 50 ° C. and a pressure of 5 kg / cm ² . Thereafter, the sample was allowed to stand at a temperature of 80 ° C. for 120 hours, and the state of the sample after being left was observed. In Table 2 below, “good” means that almost no light leakage occurs, “bad” means that the end of the polarizing plate is whitened, and “unevaluable” means that the glass plate and polarizing plate It means that it was not possible to evaluate because peeling occurred.

(Reworkability test)
The adhesive strength was measured according to the JIS Z0237 adhesive tape / adhesive sheet test method. That is, from the polarizing plate produced in each example and each comparative example, a sample cut to a width of 25 mm was bonded to a glass plate, and autoclaved for 20 minutes under conditions of a temperature of 50 ° C. and a pressure of 5 kg / cm ^2. went. Thereafter, using a tensile tester, the adhesive strength (N / 25 mm) was measured at a peeling angle of 90 degrees and a peeling speed of 0.3 m / min, and the peeled state was observed (measuring environment: 20 ° C./50%). RH). In Table 2 below, “af” indicates interface fracture.

  As can be seen from the above table, the optical members (Examples 1 to 3) using the pressure-sensitive adhesive compositions (1) to (3) of the present invention contain (A3) a crosslinkable functional group-containing (meth) acrylate monomer. Compared to the optical member using the pressure-sensitive adhesive composition of Comparative Examples 1 and 2 whose amount is outside the scope of the present invention, it is excellent in durability (heat resistance, moist heat resistance), light leakage resistance, and reworkability. I can confirm.

Claims (5)

(A1) 98.9 parts by mass or less exceeding 94 parts by mass of (meth) acrylate monomer, (A2) 1 part by mass to 5 parts by mass of macromonomer, and (A3) carboxyl group, amino group, amide group, hydroxy (Meth) acrylic polymer obtained by polymerizing 0.1 part by weight or more and less than 1 part by weight of a (meth) acrylate monomer containing at least one crosslinkable functional group selected from the group consisting of a group and an acetoacetoxy group A) [However, the total amount of (A1), (A2) and (A3) is 100 parts by mass];
A curing agent (B) having a functional group that reacts with the crosslinkable functional group,
A pressure-sensitive adhesive composition having a gel fraction of 55% or more and 80% or less.   The adhesive composition of Claim 1 whose adhesive force with respect to glass is 2.0-8.0N / 25mm.   The pressure-sensitive adhesive composition according to claim 1 or 2, further comprising a silane coupling agent.   The compounding quantity of the said hardening | curing agent (B) is 0.05 mass part or more and 1 mass part or less with respect to 100 mass parts of said (meth) acrylic-type polymers (A), Any one of Claims 1-3. 2. The pressure-sensitive adhesive composition according to 1.   An optical member provided with the adhesive layer formed from the adhesive composition of any one of Claims 1-4.