JP5280798B2 - Adhesive for optical members - Google Patents

Description

  The present invention relates to an adhesive for optical members and an optical member with an adhesive using the same. More specifically, the present invention relates to an optical member pressure-sensitive adhesive and an optical member with pressure-sensitive adhesive for attaching a glass substrate to various optical members such as a polarizing plate, an antireflection film, and an electromagnetic wave shielding film.

A liquid crystal display or a plasma display is formed by bonding various optical members such as a polarizing plate, an antireflection film, an electromagnetic wave shielding film, and a glass substrate together. Adhesives are usually used for laminating these optical members because of their good workability and high reliability of adhesive properties. In general, a release liner or the like is used for the purpose of protecting the surface of the pressure-sensitive adhesive layer, and a plastic film is used as the release liner particularly in electronic applications that require cleanliness. Plastic materials such as plastic films have high electrical insulation, and generate static electricity during friction and peeling. The static electricity attracts surrounding dust and causes electrostatic breakdown of electronic components. In order to prevent the generation of static electricity, the following methods (for example, see Patent Documents 1, 2, and 3) have been proposed.
(1) To impart antistatic properties to the release liner.
(2) An antistatic agent layer is provided between the release liner and the pressure-sensitive adhesive layer or on the side having no pressure-sensitive adhesive layer.
(3) To impart antistatic properties to the pressure-sensitive adhesive layer.

JP 58-191777 A JP-A-7-26223 JP-A-1-253482

However, the above method has the following problems.
The method (1) is a method of kneading a low molecular surfactant, a polymer antistatic agent, metal powder, and carbon black into a base film, and has a problem that the antistatic effect is insufficient.
The method (2) is a method of providing an antistatic layer made of a surfactant, an antistatic resin, a conductive resin or the like, which also has a problem that the antistatic effect is insufficient.
The method (3) is a method of kneading a low molecular surfactant, a polymer antistatic agent, a metal powder, and carbon black into the pressure-sensitive adhesive layer. Deterioration of durability due to surfactant bleed-out, pressure-sensitive adhesive layer There are problems such as a decrease in transparency.
As described above, the pressure-sensitive adhesive for optical members is required to have not only antistatic properties but also excellent durability, adhesive strength and transparency suitable for long-term use such as polarizing plate applications.

As a result of intensive studies to solve the above problems, the present inventors have arrived at the present invention. That is, the present invention relates to a (meth) acrylate-based copolymer (A) having an active hydrogen atom-containing group (h) (hereinafter sometimes simply referred to as (A)), a crosslinking agent (B) and a silane. A pressure-sensitive adhesive containing a coupling agent (C), wherein the copolymer (A) has a group represented by the general formula (1) in a side chain, and AO in the general formula (1) is an oxy copolymer units an ethylene group adhesive for bonding the optical member and the glass substrate containing 20 to 50 wt% based on the weight of (a); a pressure-sensitive adhesive layer including the pressure-sensitive adhesive, the optical element An optical member with a pressure-sensitive adhesive on at least a part of at least one surface thereof; and an image display device in which the optical member and a glass substrate are bonded together using the pressure-sensitive adhesive.
_{-COOCH 2 CH (OH) CH 2} O- (AO) n -R (1)
In the formula, R represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, AO represents an oxyalkylene group having 2 to 4 carbon atoms, and n represents a number of 10 to 50.

The pressure-sensitive adhesive of the present invention has the following effects.
(1) Excellent antistatic properties.
(2) Excellent transparency.
(3) Little change with time in adhesive strength.

In the present invention, the active hydrogen in the (meth) acrylate copolymer (A) having an active hydrogen atom-containing group (h) [hereinafter sometimes simply referred to as copolymer (A) or (A)] Examples of the atom-containing group (h) include a hydroxyl group, a carboxyl group, a primary amino group, a secondary amino group, and a thiol group. Among these, since the copolymer (A) has a group represented by the general formula (1) in the side chain, a hydroxyl group is included as an essential active hydrogen atom-containing group (h). In addition, the active hydrogen atom-containing group (h) is preferably a combination of a carboxyl group and a hydroxyl group contained in the group represented by the general formula (1) from the viewpoint of adhesiveness. When the copolymer (A) has an active hydrogen atom-containing group (h), a reaction between the active hydrogen atom, a crosslinking agent (B) and a silane coupling agent (C) described later occurs, and the adhesive is excellent. Function can be demonstrated.

The copolymer (A) in the present invention can exhibit an excellent function as an adhesive, particularly an antistatic property, by having a group represented by the general formula (1) in the side chain.
_{-COOCH 2 CH (OH) CH 2} O- (AO) n -R (1)
In the formula, R represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, AO represents an oxyalkylene group having 2 to 4 carbon atoms, and n represents a number of 10 to 50.

Among R, as the alkyl group having 1 to 18 carbon atoms, methyl group and ethyl group, and linear or branched propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group Lauryl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group and octadecyl group. Of these, alkyl groups having 1 to 12 carbon atoms are preferred from the viewpoint of antistatic properties as an adhesive.

Examples of the oxyalkylene group having 2 to 4 carbon atoms represented by AO include oxyethylene group, 1,2-oxypropylene group, 1,3-oxypropylene group, 1,2-oxybutylene group and 1,4-oxybutylene. Groups. Of these, oxyethylene groups and 1,2-oxypropylene groups are preferable from the viewpoint of antistatic properties of the pressure-sensitive adhesive.

n is a number of 10 to 50, preferably a number of 12 to 45, more preferably a number of 15 to 40, from the viewpoint of the antistatic property of the pressure-sensitive adhesive. In addition, (AO) _n may be a combination of two or more oxyalkylene groups, and their bonding mode may be block, random or a combination thereof.
Since (AO) _n is usually an alkylene oxide adduct structure, there is a distribution in the number of moles added, so n is an average value and is not necessarily an integer.

In the copolymer (A) in the present invention, the unit in which AO in the general formula (1) is an oxyethylene group is 20 to 50% by weight based on the weight of the copolymer (A), preferably 25. Contains ~ 45 wt%. When the unit in which (AO) is an oxyethylene group is less than 20% by weight, the antistatic performance is insufficient, and when it exceeds 50% by weight, the adhesion to the glass substrate is insufficient.

In the copolymer (A), the weight ratio of the unit in which AO in the general formula (1) is an oxyethylene group is usually determined from the charged amount of each raw material component during the production of the copolymer (A). Can be calculated. When AO is an oxyethylene group alone or an oxyethylene group and a 1,2-oxypropylene group and does not contain an oxyalkylene group other than AO derived from the group represented by the general formula (1), By analyzing the copolymer by this method, the content of the oxyethylene group unit can be quantified.

H ¹ -NMR is measured using a mixture of copolymer (A) and methyl methacrylate as an internal standard substance and deuterated chloroform as a solvent. The content of the oxyethylene group unit in (A) can be determined from the ratio of the area of the 3.6 ppm peak derived from the oxyethylene group to the area of the 6.2 ppm peak derived from the double bond of methyl methacrylate. . For example, (A) x (g) and methyl methacrylate y (g) are uniformly mixed and H ¹ -NMR is measured, and the ratio of the peak area of 3.6 ppm to the peak area of 6.2 ppm is determined. If it is set to Z, content (weight%) of the oxyethylene group unit in (A) can be calculated with the following formula.
Content of oxyethylene group unit in (A) (wt%)
= (1100 × y × Z) / (86 × x)

The copolymer (A) is a (meth) acrylate copolymer precursor (A ₀ ) having a carboxyl group [hereinafter, simply referred to as a copolymer precursor (A ₀ ) or (A ₀ ). Can be obtained by reacting the carboxyl group of the compound represented by formula (2) with the glycidyl group of the compound represented by the general formula (2).

  In the formula, R represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, AO represents an oxyalkylene group having 2 to 4 carbon atoms, and n represents a number of 10 to 50. Examples and preferred examples of the alkyl group having 1 to 18 carbon atoms, examples and preferred examples of AO, and preferred examples of n are the same as described above.

As the monomer constituting the copolymer precursor (A ₀ ), a carboxyl group-containing monomer (a1) is essential, and a (meth) acrylate monomer (a2) and other monomers (a3) not containing a carboxyl group are included. The copolymer precursor (A ₀ ) is a copolymer mainly composed of a (meth) acrylate structure.

Examples of the carboxyl group-containing monomer (a1) include unsaturated monobasic acids [(meth) acrylic acid, crotonic acid, cinnamic acid, vinylbenzoic acid, etc.], unsaturated dibasic acids [maleic acid, itaconic acid, fumaric acid, citracone Acid and mesaconic acid, etc.], monoester of unsaturated dibasic acid [monoalkyl ester of unsaturated dibasic acid], succinic acid monoester [succinic anhydride ring-opening adduct of 2-hydroxyalkyl (meth) acrylate, Succinic anhydride ring-opening adduct of polyoxyalkylene mono (meth) acrylate, succinic anhydride ring-opening adduct of caprolactone adduct of 2-hydroxyalkyl (meth) acrylate, and a mixture of two or more of these It is done.

  Among the carboxyl group-containing monomers (a1), from the viewpoint of the balance between the adhesive strength and durability of the pressure-sensitive adhesive, anhydrous (meth) acrylic acid and poly (degree of polymerization = 2-30) oxyalkylene mono (meth) acrylate are preferable. A succinic acid ring-opening adduct, more preferably (meth) acrylic acid.

Examples of the (meth) acrylate monomer (a2) not containing a carboxyl group include alkyl (meth) acrylate (a21) and other (meth) acrylates (a22). Of the (meth) acrylate monomers (a2) not containing a carboxyl group, alkyl (meth) acrylate (a21) is preferable from the viewpoint of tackiness.

Examples of the alkyl (meth) acrylate (a21) include (meth) acrylates having 1 to 18 carbon atoms in the alkyl group, such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and n-butyl (meth) ) Acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, neopentyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) ) Acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, myristyl (meth) acrylate, cetyl (meth) acrylate, and stearyl (meth) acrylate. Among these, alkyl (meth) acrylates having an alkyl group having 1 to 8 carbon atoms are preferable from the viewpoint of the antistatic property of the pressure-sensitive adhesive.

Other (meth) acrylates (a22) include hydroxyalkyl (meth) acrylate, amino group-containing (meth) acrylate, and active hydrogen atom-containing (meth) acrylate such as polyoxyalkylene glycol mono (meth) acrylate, and alkoxy. Examples include polyoxyalkylene glycol (meth) acrylate.

Examples of the hydroxyalkyl (meth) acrylate include those having 2 to 4 carbon atoms in the alkyl group, such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate.

Examples of amino group-containing (meth) acrylates include aminoethyl (meth) acrylate, monomethylaminoethyl (meth) acrylate, and monoethylaminoethyl (meth) acrylate.

Examples of polyoxyalkylene glycol mono (meth) acrylates include those having 2 to 4 carbon atoms of an alkylene group, such as poly (polymerization degree 2 to 100) oxyethylene glycol mono (meth) acrylate and poly (polymerization degree 2 to 100) oxy. Examples include propylene glycol mono (meth) acrylate.

Examples of the alkoxypolyoxyalkylene glycol (meth) acrylate include those having an alkoxy group having 1 to 4 carbon atoms and an alkylene group having 2 to 4 carbon atoms, such as methoxypoly (degree of polymerization 2 to 100) oxyethylene glycol (meth) acrylate and methoxypoly (Polymerization degree 2-100) Oxypropylene glycol (meth) acrylate etc. are mentioned.

Examples of the other (meth) acrylate (a22) further include dialkylaminoalkyl (meth) acrylate, aromatic group-containing (meth) acrylate, and alicyclic group-containing (meth) acrylate.

Of the other (meth) acrylates (a22), active hydrogen atom-containing (meth) acrylates are preferable from the viewpoint of cohesive strength of the pressure-sensitive adhesive.

Among the monomers constituting the copolymer precursor (A ₀ ), other monomers (a3) include (meth) allyl monomers (allyl alcohol, methallyl alcohol, allyl acetate, polyoxyalkylene allyl ether, etc.), carbonized Hydrogen monomers [ethylene, propylene, butadiene, isoprene, neoprene, isobutylene, diisobutylene, styrene, vinyltoluene, etc.] (a32), amide group-containing monomers [(meth) acrylamide, methylol (meth) acrylamide, dimethylaminoethyl (meth) Acryamide, etc.], carboxylic acid vinyl esters [vinyl acetate, etc.], alkyl vinyl ethers [methyl vinyl ether, etc.] and unsaturated dicarboxylic acid dialkyl esters [maleic acid dimethyl ester, maleic acid dibutyl ester, etc.] And the like.

The molar ratio (a1) / (a2) / (a3) of the monomer constituting the copolymer precursor (A ₀ ) is usually 5 to 50/40 to 95/0 to 10 in terms of mol%. Yes, preferably 10-40 / 55-90 / 0-5.

When (a2) and (a3) are used as a monomer having an oxyethylene group [for example, polyoxyethylene glycol mono (meth) acrylate, methoxypolyoxyethylene glycol (meth) acrylate, etc.], a copolymer precursor is used. Based on the weight of the body (A ₀ ), the oxyethylene group unit is preferably used in a proportion of preferably 20% by weight or less, more preferably 10% by weight or less, particularly preferably not used at all. . If it is 20% by weight or less, the possibility of gelation during polymerization tends to be reduced.

Weight average molecular weight of the copolymer precursor (A ₀ ) [hereinafter abbreviated as Mw, and measurement is based on gel permeation chromatography (GPC) method (polystyrene conversion). ] Is preferably 1,000,000 from the viewpoint of durability, more preferably 1,100,000, particularly preferably 1,200,000, and a preferable upper limit from the viewpoint of coating properties is 2,000,000, More preferably, it is 1,900,000, and particularly preferably 1,800,000.

The lower limit of Tg of (A ₀ ) is preferably −100 ° C., more preferably −90 ° C., particularly preferably −80 ° C. from the viewpoint of the adhesive strength of the pressure-sensitive adhesive. Further, from the viewpoint of tackiness of the pressure-sensitive adhesive, the upper limit is preferably 30 ° C, more preferably 0 ° C, and particularly preferably -10 ° C.
Furthermore, (A ₀ ) may be used as a mixture of two or more.

The method for producing the copolymer precursor (A ₀ ) is not particularly limited, and a known method can be used. A radical polymerization method is preferable, and a solution polymerization method is particularly preferable because the molecular weight is easily adjusted.

Solvents used in the solution polymerization include esters (C2-C8, for example, ethyl acetate, butyl acetate), alcohols (C1-C8, for example, methanol, ethanol, octanol), hydrocarbons (C4-C8, Examples thereof include cyclohexane and toluene, and ketones (having 3 to 9, for example, methyl ethyl ketone).

In the present invention, the compound of the general formula (2) is added with 10 to 50 moles of an average of 2 to 4 alkylene oxides in water, a glycol having 2 to 4 carbon atoms or an alkanol having 1 to 18 carbon atoms, Can be obtained by glycidyl etherification of the hydroxyl group (however, when water or glycol is used, one of the hydroxyl groups).

Examples of the glycol having 2 to 4 carbon atoms include ethylene glycol, propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediool and the like. Examples of the alkanol having 1 to 18 carbon atoms include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, t-butyl alcohol, 2-ethylexyl alcohol, lauryl alcohol and stearyl alcohol. .

Examples of the alkylene oxide include ethylene oxide, 1,2-propylene oxide, 1,2-butylene oxide, 1,4-butylene oxide, and the like. This is the same as described in the description of 1).

The glycidyl etherification reaction can be carried out by reacting an alkylene oxide adduct with epichlorohydrin in the presence of an alkali metal hydroxide. As the alkali metal hydroxide, a solid (granular or powder) or aqueous solution (concentration of 30% by weight or more) of sodium hydroxide or potassium hydroxide can be used, but a solid is preferable from the viewpoint of suppressing side reactions. Water of 40 ° C. or lower, preferably 10 to 40 ° C., is usually added to the reaction mixture after the reaction to dissolve and separate excess alkali metal hydroxide and product salt. After liquid separation, an alkali adsorbent is added to the organic layer, and epichlorohydrin is distilled off preferably under a reduced pressure (preferably −85 KPaG or less) at 70 to 120 ° C., followed by filtration to obtain a high-purity glycidyl ether. be able to.

The copolymer (A) in the present invention can be obtained by mixing, heating, and reacting the copolymer precursor (A ₀ ) and the compound of the general formula (2). The reaction temperature is preferably 50 to 150 ° C. The reaction time is preferably 3 to 50 hours. Moreover, you may use a well-known catalyst (for example, 2-methylimidazole) as needed. The reaction solvent is preferably an ester (having 2 to 8 carbon atoms such as ethyl acetate or butyl acetate), a hydrocarbon (having 4 to 8 carbon atoms such as cyclohexane or toluene) and a ketone (having 3 to 9 carbon atoms such as methyl ethyl ketone).

The charge ratio of the compound of (A ₀ ) to the general formula (2) is 20-50% by weight of oxyethylene units based on the weight of (A), and the formula (2) with respect to the carboxyl group in (A ₀ ) It is preferable that the equivalent ratio of glycidyl groups in the compound is 0.1-1. If the equivalent ratio of glycidyl groups is greater than 1, unreacted compound of general formula (2) remains, causing a decrease in adhesive strength. Moreover, since the excess carboxyl group remains as an active hydrogen atom containing group (h) in a copolymer (A) as the equivalent ratio of a glycidyl group is 0.1-1, it is preferable from an adhesive viewpoint.

As another production method of the copolymer (A) in the present invention, a (meth) acrylate having a glycidyl group is used as one of the constituent monomers as a copolymer precursor, and the copolymer precursor obtained is A method of reacting a glycidyl group with an alkylene oxide adduct represented by HO— (AO) _n —R can be mentioned. A method of reacting the copolymer precursor (A ₀ ) with the glycidyl ether compound represented by the general formula (2) is preferable from the viewpoint of the simplicity of the production process and the yield.

  The lower limit of Mw of the copolymer (A) in the present invention is preferably 1,100,000, more preferably 1,200,000, particularly preferably 1,300,000, from the viewpoint of durability. Therefore, the preferable upper limit is 2,100,000, more preferably 2,000,000, and particularly preferably 1,900,000.

The lower limit of Tg of (A) is preferably −100 ° C., more preferably −90 ° C., particularly preferably −80 ° C. from the viewpoint of the adhesive strength of the pressure-sensitive adhesive. Further, from the viewpoint of tackiness of the pressure-sensitive adhesive, the upper limit is preferably 30 ° C, more preferably 0 ° C, and particularly preferably -10 ° C.

  In this invention, a crosslinking agent (B) is an essential component which improves the cohesion force of an adhesive. As the crosslinking agent (B), an organic compound (B1) having 2 to 5 reactive functional groups in one molecule capable of reacting with the active hydrogen atom-containing group (h) in (A), and a valence of 2 At least one selected from the group consisting of polyvalent metal chelate compounds (B2) which are ˜4 is preferred. Examples of the reactive functional group include an isocyanate group, an epoxy group, a hydrazide group, an oxazolinyl group, and an aziridinyl group.

  Examples of the organic compound (B1) in the crosslinking agent (B) include polyisocyanate, polyepoxide, hydrazide, oxazoline compound, and aziridine compound.

  Polyisocyanates include cycloaliphatic diisocyanates such as isophorone diisocyanate and dicyclohexylmethane diisocyanate, aromatic diisocyanates such as tolylene diisocyanate and diphenylmethane diisocyanate, araliphatic diisocyanates such as xylylene diisocyanate, and part of the isocyanate groups of these diisocyanates. And carbodiimide, uretdione, uretoimine, urea, burette, isocyanurate, and / or a urethane group, and an isocyanate-terminated urethane prepolymer obtained by reacting an excess amount of diisocyanate with an active hydrogen compound.

Examples of the active hydrogen compound include low-molecular polyvalent (divalent to tetravalent or higher) alcohols and divalent to trivalent poly (degree of polymerization = 2 to 30) oxyalkylene (C2-4) polyols.

  Examples of the low molecular weight polyhydric alcohol include aliphatic dihydric alcohols (for example, ethylene glycol, diethylene glycol, propylene glycol, 1,3- and 1,4-butanediol, 1,6-hexanediol, 3-methylpentanediol and neo Pentyl glycol), aliphatic trihydric alcohols (eg glycerin and trimethylolpropane); other alicyclic alcohols, aromatic ring-containing alcohols, pentaerythritol, α-methylglucoside, sorbitol, xylit, mannitol, glucose, fructose, Examples thereof include sugar, dipentaerythritol, and polyglycerol (degree of polymerization 2 to 20).

Examples of the divalent to trivalent polyoxyalkylene polyol include polyether polyols obtained by adding an alkylene oxide to the above low-molecular polyhydric alcohol or polyhydric phenol bisphenol A).

  The polyisocyanate exemplified above may be blocked with a blocking agent. Examples of the blocking agent include phenol compounds; active methylene compounds; lactams; oximes; alcohols; secondary aromatic amines; mercapto compounds; imidazole compounds; acid amides; acid imides and bisulfites.

  The NCO content (% by weight) in the urethane prepolymer is usually 3 to 35%. Of the polyisocyanates, an isocyanate-terminated urethane prepolymer is preferable from the viewpoint of adhesive strength to a glass substrate. As a commercially available isocyanate-terminated polyurethane prepolymer preferable as a crosslinking agent, for example, “Coronate L” manufactured by Nippon Polyurethane Co., Ltd., an isocyanate-terminated prepolymer composed of trimethylolpropane and TDI) can be mentioned.

  Examples of the polyepoxide include bisphenol A diglycidyl ether, trimethylolpropane triglycidyl ether, polyalkylene glycol polyglycidyl ether, and diglycidyl ether of bisphenol A alkylene oxide adduct.

  Examples of hydrazides include polycarboxylic acids [aliphatic polycarboxylic acids (oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid and maleic acid), aromatic polycarboxylic acids (phthalic acid, terephthalic acid, isophthalic acid and naphthalene dicarboxylic acid). Acid) and the like] and alkylene (carbon number 2 to 6) dihydrazide (ethylene-1,2-dihydrazide, propylene-1,3-dihydrazide, etc.).

  Examples of the oxazoline compound include 2-oxazoline, 2-methyl-2-oxazoline, 2-ethyl-2-oxazoline, 2-isopropyl-2-oxazoline, 2-n-propyl-2-oxazoline, and the like.

  Examples of the aziridine compound include polyamine derivatives [1,1 ′-(methylene-di-p-phenylene) bis-3,3-aziridinylurea, 1,1 ′-(hexamethylene) bis-3,3-aziridinylurea, etc. ], Poly (2-aziridinylpropionate) of low molecular weight polyhydric alcohol [ethylenebis- (2-aziridinylpropionate), trimethylolpropane-tris- (2-aziridinylpropionate) 2,4,6-triaziridinyl-1,3,5-triazine and the like].

  The lower limit of the molecular weight per functional group of the organic compound (B1) is preferably a molecular weight of 40, more preferably 60 from the viewpoints of cohesive strength and adhesive strength of the pressure-sensitive adhesive. Moreover, a preferable upper limit is 20,000 molecular weight, More preferably, it is 10,000, Most preferably, it is 5,000.

  As the polyvalent metal chelate compound (B2) in the crosslinking agent (B), a polyvalent (2-4 valent) metal [IIA group (Mg, Ca, etc.), IIB group (Zn etc.), IIIA group (Al etc.) ), IVA group (Sn, Pb, etc.), transition metals (Ti, Zr, manganese, Fe, Co, Ni, Cu, etc.), etc.] Chelate compounds (β diketones, acetylacetone, acetoacetates, etc., chelate compounds ). Commercially available products of aluminum acetylacetonate include “Aluminum Chelate A (W)” manufactured by Kawaken Fine Chemical Co., Ltd. and “Narsem Aluminum” manufactured by Nippon Chemical Industry Co., Ltd. When the copolymers (A) and (B2) are mixed, the chelate ligand in (B2) is released, and the polyvalent metal is coordinated to the carboxyl group of the copolymer (A) to perform crosslinking.

The molecular weight per valence of the polyvalent metal of the polyvalent metal chelate compound (B2) is preferably 40, more preferably 50 from the viewpoints of cohesive strength and adhesive strength of the adhesive, and from the viewpoint of cohesive strength and adhesive strength. The upper limit is 140, more preferably 130, particularly preferably 110.

As a crosslinking agent (B), the crosslinking agent as described in Unexamined-Japanese-Patent No. 2008-7702 is further mentioned.

  The amount of the crosslinking agent (B) used is expressed in terms of the equivalent ratio of the active hydrogen atom in the copolymer (A) and (B) that reacts with the active hydrogen atom. From the viewpoint of adhesive strength, the amount is preferably 1 / 0.01 to 1/2, more preferably 1 / 0.02 to 1/1, and the weight ratio (A) / (B) is preferably 99. .9 / 0.1 to 90/10.

In this invention, the silane coupling agent (C) which an adhesive contains is an essential component for further improving the adhesive force with respect to a glass substrate. Examples of the silane coupling agent (C) include polymerizable unsaturated group-containing silicon compounds (vinyltrimethoxysilane, vinyltriethoxysilane, methacryloxypropyltrimethoxysilane, etc.), epoxy group-containing silicon compounds [3-glycidoxypropyl Trimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, etc.], amino group-containing silicon compound [3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxy Silane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane and the like], 3-chloropropyltrimethoxysilane and the like, and mixtures thereof. Examples of commercially available 3-glycidoxypropyltrimethoxysilane include “KBM-403” manufactured by Shin-Etsu Chemical Co., Ltd. From the viewpoint of adhesive strength to a glass substrate, an epoxy group-containing silicon compound is preferable.

The amount of the silane coupling agent (C) used is generally 0.001 to 10% based on the weight of the copolymer (A), and preferably 0.005 to 5 from the viewpoint of the adhesive strength and durability of the adhesive. %.

In the pressure-sensitive adhesive of the present invention, the preferred contents (total of 100% by weight) of the copolymer (A), the crosslinking agent (B) and the silane coupling agent (C) based on the weight of the solid content of the pressure-sensitive adhesive are as follows. Is as follows. In the present invention, the “solid content” means components other than water and organic solvents.

The copolymer (A) is preferably 88 to 99.89% by weight, more preferably 90 to 99.45% by weight; the crosslinking agent (B) is preferably 0.1 to 9% by weight, more preferably 0 0.5-8 wt% The silane coupling agent (C) is preferably 0.01-3 wt%, more preferably 0.05-2 wt%.

The pressure-sensitive adhesive of the present invention preferably contains an organic solvent (S) from the viewpoint of coatability. Examples of the organic solvent (S) include the organic solvents used when solution copolymerizing the copolymer precursor (A ₀ ). The content of the organic solvent (S) is preferably 90% by weight or less, more preferably 10 to 90% by weight of the pressure-sensitive adhesive.

The pressure-sensitive adhesive of the present invention includes a tackifier resin (D1), a plasticizer (D2), a filler (D3), a pigment (D4), and an ultraviolet absorber as long as the effects of the present invention are not impaired. At least one additive (D) selected from the group consisting of (D5) and an antioxidant (D6) can be further added. As specific examples of (D1) to (D6), those described in Japanese Patent Application Laid-Open No. 2008-7702 can be used within the range of the amounts described in the same publication.

The viscosity of the pressure-sensitive adhesive of the present invention is usually 100 to 10,000 mPa · s at 25 ° C. (the measurement method is the method described in JIS-K7117-2).

The antistatic pressure-sensitive adhesive of the present invention is (A), (B), (C) If necessary, (S) and (D) are uniformly mixed with an ordinary mixing device (mixing tank equipped with a stirrer, static mixer, etc.) It can manufacture by mixing. (D) may be added at the stage of production of (A) (raw material before production, reaction product during production or product after production).

  The optical member with a pressure-sensitive adhesive of the present invention has a pressure-sensitive adhesive layer made of the pressure-sensitive adhesive on at least a part of at least one side of the optical member. Examples of the optical member include a film-like optical member such as a polarizing plate, a retardation plate, an optical compensation film, a brightness enhancement film, and a laminate of these.

  As a method for forming the pressure-sensitive adhesive layer, a method in which a pressure-sensitive adhesive is applied to at least a part of at least one side of the film-like optical member by an appropriate method such as a casting method or a coating method and dried, Examples thereof include a method of transferring from the provided release liner onto the surface of the optical member. As a coating method, a roll coating method (reverse coating, gravure coating, etc.), a spin coating method, a screen coating method, a fountain coating method, a dipping method, and a spray method can be employed. After applying the pressure-sensitive adhesive, a pressure-sensitive adhesive layer having a predetermined thickness can be obtained by volatilizing the solvent and water in the drying step.

  Examples of heating means for forming the pressure-sensitive adhesive layer include hot air (60 to 150 ° C.), (near) infrared rays, and high frequencies. In addition, examples of curing conditions include about 3 to 7 days at room temperature or about 12 to 72 hours at 45 ° C. The coating thickness (after drying) of the pressure-sensitive adhesive layer in the present invention is usually 1 to 50 μm, and preferably 5 to 30 μm from the viewpoint of durability and adhesion.

  Examples of the image display device to which the optical member with an adhesive of the present invention is attached include a liquid crystal display, an organic EL display, a plasma display, a field emission display, and the like.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. In the following, “parts” represents parts by weight, and “%” represents% by weight.

[Production of (Meth) acrylate Copolymer Precursor (A ₀ )]
Production Example 1
In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping funnel and nitrogen gas inlet tube, 70 parts of ethyl acetate was charged and the temperature was raised to 78 ° C. a monomer compounded liquid in which 264 parts (2.1 mole parts) of n-butyl acrylate and 36 parts (0.5 mole parts) of acrylic acid were blended, and 2,2′-azobis (2,4-dimethylvaleronitrile); An initiator solution in which 1 part was dissolved in 55 parts of ethyl acetate was subjected to radical polymerization by continuously dropping it over 4 hours from a separate dropping funnel while blowing nitrogen into the reaction vessel. After completion of dropping, the mixture was aged for 2 hours, and then an initiator solution in which 0.6 part of 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved in 28 parts of ethyl acetate was continuously added over 2 hours using a dropping funnel. Added. Furthermore, after continuing the polymerization reaction at the boiling point (80 ° C.) for 2 hours, 1047 parts of ethyl acetate was added to prepare a solution (solid content concentration = 20%) of the (meth) acrylate copolymer precursor (A ₀ 1). Obtained. Mw was 1.5 million.

Production Example 2
In Production Example 1, the same as Production Example 1 except that 204 parts (1.6 mole parts) of n-butyl acrylate and 60 parts (0.6 mole parts) of methyl methacrylate were used instead of 264 parts of n-butyl acrylate. Thus, a solution (solid content concentration = 20%) of the (meth) acrylate copolymer precursor (A ₀ 2) was obtained. Mw was 1.4 million.

[Production of alkylene oxide adduct]
Production Example 3
In a 2 liter stainless steel autoclave with a stirring and temperature control function that was previously dried in a thermostat at 150 ° C. for 8 hours, 93 parts (0.5 mole part) of lauryl alcohol and 2.0 parts of 45% potassium hydroxide aqueous solution were added. The mixed system was replaced with nitrogen. Thereafter, dehydration was performed at 100 ° C. for 2 hours under reduced pressure (1 to 5 mmHg). Subsequently, 220 parts (5 mole parts) of ethylene oxide (hereinafter abbreviated as EO) were introduced so that the gauge pressure was 1 to 3 kgf / cm ² , thereby obtaining a lauryl alcohol EO 10 mole adduct (z1).

Production Examples 4 to 9 and Comparative Production Example 1
In Production Example 3, the alkylene oxide adducts (z2) to (z7) and (Ratio) were prepared in the same manner as in Production Example 3 except that the amount of alkylene oxide described in Table 1 was used instead of 220 parts of EO. z1) was obtained. In Table 1 and below, / represents a random bond.

[Production of glycidyl ether compound]
Production Example 10
(Z1) 315 parts, epichlorohydrin 83 parts, toluene 250 parts in a reaction tank equipped with a stirrer, temperature control measures, wet pulverizer (attached to the outside of the reaction tank), and the inside of the reaction tank under a nitrogen atmosphere, 38 parts of granular sodium hydroxide under a nitrogen atmosphere at 19 ° C. was dropped intermittently at 19-29 ° C. over 9.5 hours, and the sodium hydroxide in the reaction vessel was pulverized using a wet pulverizer during this period. Thereafter, the reaction was aged at 25 to 29 ° C. for 5 hours to form glycidyl ether. The wet pulverizer was operated continuously from the start of dropping sodium hydroxide to the end of reaction ripening. After cooling the inside of the tank to 16 ° C., 200 parts of 23 ° C. water was added in the range of 20 to 28 ° C., stirred for 0.5 hours, and allowed to stand at 17 ° C. for 0.5 hours. 10 parts of “KYOWARD 600” (manufactured by Kyowa Chemical Industry Co., Ltd .; alkali adsorbent) was added to the remaining upper layer (organic layer), the temperature was increased under reduced pressure, and the mixture of epichlorohydrin and toluene was increased to 120 ° C. and −98.0 KPaG. The residue was filtered and circulated using “Radiolite # 700” (manufactured by Kyowa Chemical Industry Co., Ltd .; diatomaceous earth filter aid) to obtain lauryl alcohol EO10 mol glycidyl ether compound (g1). .

Production Examples 11 to 16 and Comparative Production Example 2
In Production Example 10, a glycidyl ether compound was produced in the same manner as in Production Example 10 except that the alkylene oxide adduct shown in Table 2 was used in place of 315 parts of lauryl alcohol EO 10 mol adduct (z1). (G2) to (g7) and (ratio g1) were obtained. In Table 2, GE represents glycidyl ether.

[Production of (Meth) acrylate Copolymer (A)]
Production Example 17
In a reaction vessel equipped with a stirrer, a thermometer and a reflux condenser, 100 parts of the solution of the copolymer precursor (A ₀ 1) and 10 parts of the glycidyl ether compound (g1) [based on the carboxyl group of (A ₀ 1)] The equivalent ratio of glycidyl group (g1) = 0.42] and 40 parts of ethyl acetate were charged and the temperature was raised to 80 ° C. Thereafter, the reaction was continued for 10 hours to obtain a solution (solid content concentration = 20%) of the (meth) acrylate copolymer (A1) having an oxyalkylene chain in the molecular side chain. The oxyethylene unit in (A1) was 20.4% from the quantification by the measurement of the aforementioned H ¹ -NMR. The acid value of (A1) was 36, and the presence of the carboxyl group (h1) was confirmed.

Production Examples 18 to 23 and Comparative Production Examples 3 to 5
Copolymers of Production Examples 18 to 23 (A2) in the same manner as in Example 17 except that the copolymer precursor solution, glycidyl ether compound and ethyl acetate described in Table 3 were used in the amounts described in Table 3. ) To (A7) solutions (solid content concentration = 20%) and the solutions (solid content concentration = 20%) of the copolymers (ratio A1) to (ratio A3) of Comparative Production Examples 3 to 5 were produced.

[Manufacture of adhesives]
Example 1
A 75% ethyl acetate solution of an isocyanate-terminated urethane prepolymer of trimethylolpropane as a crosslinking agent (B) was added to 100 parts of the above-mentioned (meth) acrylate copolymer (A1) (solid concentration = 20%) [trade name "Coronate L" manufactured by Nippon Polyurethane Co., Ltd. 1 part and 0.05 part of 3-glycidoxypropyltrimethoxysilane [trade name "KBM-403", Shin-Etsu Chemical Co., Ltd.] as silane coupling agent (C) The pressure-sensitive adhesive (X1) of the present invention was prepared by mixing uniformly. The viscosity (measurement method: method described in JIS-K7117-2) of the pressure-sensitive adhesive (X1) was 7,200 (mPa · s) at 25 ° C.

Examples 2-7 and Comparative Examples 1-4
The solutions of Examples 2 to 7 were used in the same manner as in Example 1 except that the copolymer solution, the crosslinking agent (B) and the silane coupling agent (C) described in Table 4 were used in the amounts shown in Table 4. The pressure-sensitive adhesives (X2) to (X7) and the pressure-sensitive adhesives (ratio X1) to (ratio X4) of Comparative Examples 1 to 4 were produced. In Table 4, “Narsem *” represents aluminum acetylacetonate [trade name “Narsem Aluminum”, manufactured by Nippon Chemical Industry Co., Ltd.].

Comparative Example 5
In the same manner as in Example 1, except that 100 parts of the copolymer precursor (A ₀ 1) solution was used instead of 100 parts of the copolymer (A1) solution, X5) was prepared.

Comparative Example 6
250 parts of a solution of the copolymer precursor (A ₀ 1), 1 part of lithium perchlorate, 20 parts of polyether diol [trade name “Sanix PP-400”, manufactured by Sanyo Chemical Industries, Ltd.] and 80 of ethyl acetate Parts were mixed to obtain a blend. A pressure-sensitive adhesive of Comparative Example 6 (Ratio X6) was prepared in the same manner as in Example 1 except that 100 parts of the blend was used instead of 100 parts of the solution of the copolymer (A1).

Comparative Example 7
Into 250 parts of the copolymer precursor (A ₀ 1) solution, 2.5 parts of an alkyl phosphate antistatic agent [trade name “Phosphanol RD-510Y”, manufactured by Toho Chemical Industry Co., Ltd.] A formulation was obtained. A pressure-sensitive adhesive of Comparative Example 7 (Ratio X7) was prepared in the same manner as in Example 1 except that 100 parts of the blend was used instead of 100 parts of the solution of the copolymer (A1).

Comparative Example 8
2.5 parts of carbon black was dispersed in 250 parts of a solution of the copolymer precursor (A ₀ 1) to obtain a dispersion. A pressure-sensitive adhesive of Comparative Example 8 (ratio X8) was prepared in the same manner as in Example 1, except that 100 parts of the dispersion was used instead of 100 parts of the solution of (A1).

The pressure-sensitive adhesives (X1) to (X7) and (Ratio X1) to (Ratio X8) were separated from the release polyester film [trade name “Super Tech SP-PET38”, manufactured by Lintec Corporation]. The pressure-sensitive adhesive sheet 1 was obtained by coating with an applicator to 25 μm, drying with hot air at 60 ° C. for 1 minute and further at 100 ° C. for 1 minute, and curing at 45 ° C. for 3 days.

The obtained adhesive sheet 1 was affixed on one side of the polarizing plate to obtain an adhesive sheet 2. Using the pressure-sensitive adhesive sheet 1 and the pressure-sensitive adhesive sheet 2, the surface resistivity, transparency, adhesive strength and durability were evaluated by the following test methods. The results are shown in Table 5.

[Performance test method]
(1) Surface Specific Resistance Value After the pressure-sensitive adhesive sheet 1 was allowed to stand for 12 hours under the condition of 23 ° C. × 65% RH, the surface specific resistance of the pressure-sensitive adhesive film was measured by the method described in JIS-K6911.
(2) The total light transmittance of the transparent adhesive sheet 1 was measured by the method described in JIS-K7361-1, and evaluated according to the following criteria.
○: Total light transmittance is 85% or more ×: Total light transmittance is less than 85% (3) Adhesive strength The pressure-sensitive adhesive sheet 2 is cut into 2.5 cm × 15 cm, the release polyester film is peeled off, and alkali-free. The adhesive strength at 23 ° C. was measured on a glass plate [trade name “1737”, manufactured by Corning Inc.] by the method described in JIS-Z0237.
(4) Durability The pressure-sensitive adhesive sheet 2 was cut into 24 cm × 14 cm, and the release polyester film was peeled off and attached to the alkali-free glass plate. The obtained sample was allowed to stand for 500 hours under the conditions of 85 ° C./dry and 60 ° C./95% RH, and the presence or absence of foaming of the pressure-sensitive adhesive layer, peeling from the glass plate or floating was visually evaluated according to the following evaluation criteria. .
○: No foaming, peeling or floating is observed.
X: At least one of foaming, peeling and floating is observed.

  From the results of Table 5, it can be seen that the pressure-sensitive adhesive for optical members of the present invention has excellent antistatic properties as compared with those of Comparative Examples, and at the same time, is excellent in transparency, adhesive strength and durability.

  The pressure-sensitive adhesive for optical members of the present invention is a liquid crystal display, organic EL display, plasma display, field emission display as a pressure-sensitive adhesive for bonding various optical members such as polarizing plates, retardation plates, light diffusing plates and glass substrates. It can be used for a wide range of various image display devices such as the above, and is extremely useful.

Claims (7)

A pressure-sensitive adhesive containing a (meth) acrylate copolymer (A) having an active hydrogen atom-containing group (h), a crosslinking agent (B) and a silane coupling agent (C), wherein the copolymer (A ) Has a group represented by the general formula (1) in the side chain, and a unit in which AO in the general formula (1) is an oxyethylene group is 20 to 50 weight based on the weight of the copolymer (A). % adhesive for bonding the optical member and the glass substrate containing.
_{-COOCH 2 CH (OH) CH 2} O- (AO) n -R (1)
[Wherein, R represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, AO represents an oxyalkylene group having 2 to 4 carbon atoms, and n represents a number of 10 to 50. ]   The pressure-sensitive adhesive according to claim 1, wherein the active hydrogen atom-containing group (h) of the copolymer (A) is a carboxyl group and a hydroxyl group contained in the group represented by the general formula (1). The copolymer (A) is a copolymer obtained by reacting a (meth) acrylate copolymer precursor (A ₀ ) having a carboxyl group with a compound represented by the general formula (2). The pressure-sensitive adhesive according to claim 1 or 2.

[Wherein, R represents a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, AO represents an oxyalkylene group having 2 to 4 carbon atoms, and n represents a number of 10 to 50. ] The cross-linking agent (B) has an organic compound (B1) having 2 to 5 reactive functional groups per molecule capable of reacting with the active hydrogen atom-containing group (h) in the copolymer (A) and a valence. The pressure-sensitive adhesive according to any one of claims 1 to 3, which is at least one selected from the group consisting of polyvalent metal chelate compounds (B2) having a number of 2 to 4. Furthermore, the adhesive in any one of Claims 1-4 formed by containing an organic solvent (S). The optical member with an adhesive which has an adhesive layer which consists of an adhesive in any one of Claims 1-5 in at least one part of the at least single side | surface of an optical member. The image display apparatus formed by bonding an optical member and a glass substrate using the adhesive in any one of Claims 1-5.