JP3065923B2 - One-part acrylic pressure-sensitive adhesive composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an acrylic pressure-sensitive adhesive composition. More specifically, adhesive labels, stickers, and adhesive tapes for light packaging, wiring fixing tapes in electrical equipment, masking tapes for baking paint,
The present invention relates to a one-component crosslinked acrylic pressure-sensitive adhesive composition suitable for a tape for sealing an electrolytic capacitor and the like.

[0002]

2. Description of the Related Art Heretofore, as a one-part cross-linkable acrylic pressure-sensitive adhesive, for example, an acrylic ester, N-methylolacrylamide and / or N-alkoxymethylacrylamide, and an acrylic ester containing an epoxy group are used. Copolymerized (Japanese Patent Laid-Open No. 50-1135)
No. 39) and those comprising a carboxyl group-containing acrylic copolymer and an amino resin such as alkoxylated methylolmelamine (Japanese Patent Publication No. 48-1420).

[0003]

However, in the above, the heat treatment temperature required for crosslinking is relatively high,
In addition, there is a problem that the adhesive properties are inferior to those using a polyisocyanate crosslinking agent. An object of the present invention is to provide an acrylic pressure-sensitive adhesive which is one-packed, has excellent storage stability, can be crosslinked at a relatively low temperature, and exhibits excellent adhesive properties.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, have used a cross-linking agent comprising a blocked polyisocyanate in combination with a catalyst comprising a quaternary ammonium organic acid salt. As a result, the present inventors have found that an acrylic pressure-sensitive adhesive which can be cross-linked by a one-component treatment at a relatively low temperature and has excellent adhesive properties can be obtained, and the present invention has been achieved. That is, the present invention provides an alkyl (meth) acrylate having 4 to 12 carbon atoms in the alkyl group (a1) in an amount of 50 to 99.5% by weight,
The following unsaturated carboxylic acid or acid anhydride (a2) of (1)
A copolymer (A) having 0.5 to 10 parts by weight and optionally 0 to 40% by weight of another polymerizable monomer (a3) as a constituent unit, a blocked polyisocyanate compound (B), and the following ( A solution or emulsion type one-part acrylic pressure-sensitive adhesive composition, characterized by comprising a catalyst comprising a quaternary ammonium organic acid salt (C) obtained from the organic acid of 2). (1) Unsaturated carboxylic acid or acid anhydride selected from (meth) acrylic acid, crotonic acid, (anhydride) maleic acid, (anhydride) itaconic acid and (anhydride) fumaric acid (2) aliphatic monocarboxylic acid, fat Group polycarboxylic acids,
At least one organic acid selected from the group consisting of aromatic monocarboxylic acids, aromatic polycarboxylic acids, phenol compounds, sulfonic acid compounds and phosphoric acid compounds

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The alkyl (meth) acrylate (a1) having 4 to 12 carbon atoms in the alkyl group constituting the copolymer (A) in the present invention is, for example, a fatty acid having 4 to 12 carbon atoms. (Meth) acrylate from aliphatic alcohol [n-butyl (meth) acrylate, 2-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, octyl (meth)
Acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, etc., (meth) acrylate from alicyclic alcohol [cyclohexyl (meth) acrylate, etc.], fragrance (Meth) acrylates from aliphatic alcohols [such as benzyl (meth) acrylate] and mixtures of two or more thereof. Of these, particularly preferred are n-butyl acrylate, 2-ethylhexyl acrylate and mixtures thereof.

Unsaturated carboxylic acids or acid anhydrides (a2)
Examples thereof include monobasic acids such as (meth) acrylic acid and crotonic acid, polybasic acids such as maleic acid, itaconic acid and fumaric acid, and acid anhydrides or monoalkyl esters thereof. Preferred of these are (meta)
Acrylic acid, (anhydrous) maleic acid and itaconic acid, with acrylic acid being particularly preferred.

The other polymerizable monomer (a3) optionally used together with (a1) and (a2) includes a polymerizable monomer (a3-1) having a reactive functional group and a reactive functional group (a3-1). And a polymerizable monomer (a3-2) having no group. Examples of (a3-1) include polymerizable monomers having a hydroxyl group [such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate]; Polymerizable monomer having a group [such as (meth) acrylamide], polymerizable monomer having an epoxy group [such as glycidyl (meth) acrylate], polymerizable monomer having an amino group [N, N-dimethylamino] Ethyl (meth) acrylate, etc.], polymerizable monomer having a methylol group [such as N-methylol acrylamide], polymerizable monomer having a sulfonic acid group [such as sodium alkyl allyl sulfosuccinate], polymerization having a phosphoric acid group Monomer [phosphoric acid ester of 2-hydroxyethyl acrylate and the like] and the like.

The above (a3-2) includes, for example, (meth) acrylic acid esters of alcohols having 1 to 3 carbon atoms in the alkyl group [methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate; Acrylate, etc.), (meth) acrylic acid esters of alcohols having 13 to 18 carbon atoms in the alkyl group [tridecyl (meth) acrylate, myristyl (meth) acrylate,
Cetyl (meth) acrylate, stearyl (meth) acrylate, etc.], aromatic polymerizable monomers [styrene, vinyltoluene, etc.], polymerizable monomers having allyl group [allyl acetate, etc.], polymerization having nitrile group Monomer [(meth) acrylonitrile, (meth) α-chloroacrylonitrile, etc.], halogen-containing vinyl or vinylidene polymerizable monomer [vinyl chloride, vinylidene chloride, etc.], vinyl ester polymerizable monomer [ Vinyl acetate, vinyl propionate, vinyl butyrate, vinyl versatate, etc.] and vinyl ether-based polymerizable monomers [vinyl ethyl ether, vinyl propyl ether, vinyl isobutyl ether, etc.].

Of the above-mentioned other polymerizable monomers (a3), preferred are those having a hydroxyl group in (a3-1), and particularly preferred are those having a hydroxyl group. Ethyl (meth) acrylate. Among (a3-2), an aromatic polymerizable monomer and a vinyl ester polymerizable monomer are preferable, and styrene and vinyl acetate are particularly preferable.

[0010] The other polymerizable monomer (a3) is
Two or more kinds can be used as a mixture.

The amount of (a1) constituting the copolymer (A) is usually 50 to 99.5% by weight, preferably 60 to 99.5.
% By weight, particularly preferably 70 to 99% by weight. (A
If the amount of (1) is less than 50% by weight, tack and adhesive strength will be reduced, and if it exceeds 99.5% by weight, cohesive strength will be reduced, and the function as a pressure-sensitive adhesive will not be achieved.

The amount of (a2) is usually 0.5 to 10% by weight, preferably 1 to 8% by weight, particularly preferably 2 to 6% by weight.
% By weight. When the amount of (a2) is less than 0.5% by weight, the cohesive strength decreases, and when it exceeds 10% by weight, tack and adhesive strength at room temperature decrease.

The amount of (a3) is usually 5% by weight or less, preferably 2% by weight or less in the case of (a3-1).
In the case of 3-2), it is usually 40% by weight or less, preferably 30% by weight.
% By weight or less. If the amount of (a3) exceeds the above range, the tack and the adhesive strength at room temperature decrease.

(A1), (a2) and if necessary (a
The production of the copolymer comprising 3) can be carried out by a known polymerization method (bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization, etc.) by a known polymerization initiator (azobisisobutyronitrile, azobisisovaleronitrile). Azo-based polymerization initiators such as benzoyl peroxide, di-t-butyl peroxide, lauryl peroxide, etc.).

The weight average molecular weight (in terms of polystyrene) of the copolymer (A) in the present invention by gel permeation chromatography (GPC) is usually 5,000.
~ 1,000,000, preferably 50,000 ~ 1,000
000, more preferably 200,000 to 1,000.
It is 0,000. If the weight average molecular weight is less than 5,000, the cohesive strength will be insufficient, and if it exceeds 1,000,000, the solution viscosity will be high and handling will be difficult.

The organic polyisocyanate constituting the blocked polyisocyanate compound (B) in the present invention includes a low molecular weight polyisocyanate (b1), a free isocyanate (NCO) group from a polyol and an excess (b1). Urethane prepolymers (b2) and mixtures thereof. As the above (b1),
Aliphatic polyisocyanates [eg, hexamethylene diisocyanate (HDI), lysine diisocyanate, etc.]; Alicyclic polyisocyanates [dicyclohexylmethane diisocyanate (hydrogenated MDI), isophorone diisocyanate (IPDI), cyclohexane diisocyanate (CHDI), hydrogenated tolylene diisocyanate , Hydrogenated xylylene diisocyanate]; aromatic polyisocyanates [for example, tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MD
I), naphthylene diisocyanate (NDI), xylylene diisocyanate (XDI), α, α, α, α ′
-Tetramethylxylylene diisocyanate (TMXD
Modified isocyanates (modified isocyanurates, burettes, uretdione, carbodiimides, etc.); and mixtures of two or more of these.The urethane prepolymer (b2) having a free NCO group is also included. Examples of the constituent polyols include low molecular polyols (ethylene glycol, propylene glycol, butanediol, glycerin, trimethylolpropane, castor oil, etc.), polyether polyols [the above low molecular polyols, amines (alkanolamine, ethylenediamine, diethylenetriamine, Alkylene oxide (ethylene oxide, propylene oxide, etc.) adduct of aminoethyl piperazine, etc.), polyester polyol [low molecular weight polyol or polyether polyol and polycarbonate Bon acid (adipic acid and terephthalic acid) reaction by condensation polyester polyols, etc.] and mixtures of two or more of these resulting with the like.

In the urethane prepolymer (b2), the equivalent ratio of the NCO / OH reaction between (b1) and the polyol is usually 1.2 to 3.0, preferably 1.5 to 2.2.

The prepolymerization reaction is usually performed in the presence of a solvent. Examples of the solvent include aromatic hydrocarbons (toluene, xylene, trimethylbenzene, etc.); esters [ethyl acetate, butyl acetate, DBE
(A mixture of dimethyl succinate, dimethyl glutarate, and dimethyl adipate)]; ethers (eg, cellosolve acetate, carbitol acetate); ketones (eg, methyl ethyl ketone, cyclohexanone); and mixed solvents of two or more of these. be able to.

The reaction temperature is usually 50 to 120 ° C, preferably 70 to 100 ° C. The reaction time is usually 2 to 10 hours, preferably 5 to 8 hours.

The number average molecular weight of (b2) is not particularly limited, but is usually 500 to 10000, preferably 700 to 8
000. The content of the free NCO group in (b2) is usually 1 to 20% by weight, preferably 2 to 15% by weight.

Examples of the blocking agent constituting the blocked polyisocyanate compound (B) include oxime compounds [for example, ketoxime such as acetoxime, methyl ethyl ketoxime (MEK oxime) and methyl isobutyl ketoxime (MIBK oxime)]; lactam compounds ( ε-caprolactam, δ-valerolactam, γ
-Butyrolactam and the like); phenol compounds (for example, phenol, m-cresol, xylenol and the like); active methylene compounds [for example, malonic acid diester (for example, diethyl malonate), acetylacetone, acetoacetate (for example, ethyl acetoacetate) and the like]; alcohol compounds (E.g., methanol, ethanol, n-butanol, etc.); hydroxyl-containing ether compounds (methyl cellosolve,
Butyl cellosolve, ethyl carbitol, etc.); hydroxyl-containing ester compounds (eg, ethyl lactate, amyl lactate, etc.); mercaptan compounds (eg, butyl mercaptan, hexyl mercaptan, etc.); acid amide compounds (eg, acetanilide, acrylamide, dimer amide, etc.); Imidazole compounds (eg, imidazole, 2-ethylimidazole, etc.); acid imide compounds (eg, succinimide, phthalic imide, etc.); and mixtures of two or more of these.

Among these, oxime compounds, lactam compounds and phenol compounds are preferred.
Particularly preferred are MEK oxime, ε-caprolactam and xylenol.

The amount of the blocking agent constituting (B) is usually 1 to 2 equivalents, preferably 1.05 to 1.5 equivalents, based on the free NCO group of (b1) and / or (b2). is there. The blocking reaction temperature is usually 50 to 1
50 ° C.

The quaternary ammonium organic acid salt (C) in the present invention is a compound represented by the following general formula (1).

[0025]

Embedded image

[In the formula, R ^{1 to} R ³ are a straight-chain or branched, saturated or unsaturated hydrocarbon group having 1 to 11 carbon atoms (provided that any two of R ^{1 to} R ³ are C, A heterocyclic ring may be formed via an O or N atom);
⁴ represents an alkyl group having 1 to 8 carbon atoms or an aromatic hydrocarbon group. X ^- represents an organic acid anion group. In the above general formula (1), R ^{1 to} R ³ each independently have usually 1 to 11, preferably 1 to 8 carbon atoms. If the number of carbon atoms exceeds 11, the catalytic activity becomes insufficient. Further, the carbon number of R ⁴ is usually 1 to 8, preferably 1 to 4. If the number of carbon atoms exceeds 8, industrial production becomes difficult. Also,
In the above general formula (1), when R ^{1 to} R ⁴ are all the same, the obtained (C) has high crystallinity, so that the solubility in the resin component and the solvent is reduced, and there is a problem that it is difficult to handle during work. Occurs. Therefore, at least one of R ^{1 to} R ⁴ is
Desirably, the carbon numbers are different.

As the manufacturing method of (C), for example, the fourth method
A method of reacting a quaternary ammonium hydroxide with an organic acid, and a method of causing an anion exchange reaction between a quaternary ammonium carbonate obtained by reacting a tertiary amine with a carbonic acid diester and an organic acid. The production method is preferable in that there is no halogen element or alkali (earth) metal mixed in the process.

Examples of the diester carbonate used in the above-mentioned production method include dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate and the like, and particularly preferred is dimethyl carbonate.

The molar ratio of the tertiary amine to the carbonic acid diester in the production method is usually 1: (0.3 to 4). If necessary, a reaction solvent (methanol, ethanol, etc.) may be used. The reaction temperature is usually 30 to 150
° C, preferably 50 to 100 ° C.

The anion exchange reaction between the quaternary ammonium carbonate (a) and the organic acid (b) may be carried out in the presence or absence of a solvent. , The quaternary ammonium organic acid salt (C) can be obtained quantitatively. After the reaction, if necessary, the reaction solvent is distilled off and used as it is, or an aqueous solution or an organic solvent [methanol, ethanol, acetone, (poly) ethylene glycol, (poly) propylene glycol, γ-butyrolactone, N-
Methylpyrrolidone, etc.] solution.

In the anion exchange reaction between (a) and (b), the amount of (b) is 0.5 to 1 mol of (a).
To 4.0 mol is preferable, and it is particularly preferable to carry out the anion exchange reaction at a compounding ratio such that the pH (aqueous solution or organic solvent solution) of (C) obtained is 6.5 to 7.5.

The tertiary amine constituting (C) includes:
Aliphatic amines (trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-octylamine, diethyl-1-propylamine, etc.); alicyclic amines [N-methylpyrrolidine, N -Ethylpyrrolidine, N-methylpiperidine, N
-Ethylpiperidine, N-methylhexamethyleneimine, N-ethylhexamethyleneimine, N-methylmorpholine, N-butylmorpholine, N, N'-dimethylpiperazine, N, N'-diethylpiperazine, 1,5-diazabicyclo ( 4,3,0) -5-nonene, 1,8-diazabicyclo [5,4,0] -7-undecene, pyridine, 4-dimethylaminopyridine, picolines, 1-methylimidazole, 1,2-dimethylimidazole ,
1,4-dimethyl-2-ethylimidazole, 1,2-
Dimethylimidazoline, 1,2,4-trimethylimidazoline, 1,4-dimethyl-2-ethylimidazoline and the like]; and a mixture of two or more of these.
Of these, preferred are trimethylamine and triethylamine among aliphatic amines; and 1,5-diazabicyclo [4, among alicyclic amines.
3,0] -5-nonene, 1,8-diazabicyclo [5,
4,0] -7-undecene and 1,2,4-trimethylimidazoline.

The organic acids constituting (C) include aliphatic monocarboxylic acids [formic acid, acetic acid, octylic acid, 2-ethylhexanoic acid, etc.]; aliphatic polycarboxylic acids (oxalic acid, malonic acid, succinic acid, glutaric acid). Acids, adipic acid, etc.); aromatic monocarboxylic acids (benzoic acid, toluic acid, ethylbenzoic acid, etc.); aromatic polycarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid, nitrophthalic acid, trimellitic acid, etc.); phenol Compounds (phenol, resorcin, etc.); sulfonic acid compounds (alkylbenzenesulfonic acid, toluenesulfonic acid, benzenesulfonic acid, etc.);
Phosphate compounds and the like. The organic acids can be used alone or as a mixture of two or more. Of these, preferred are aliphatic carboxylic acid compounds and aromatic carboxylic acid compounds, and particularly preferred are octylic acid and formic acid.

Particularly preferred as (C) used in the present invention are methyltriethylammonium octylate, N-8-methyl-1,8-diazabicyclo [5,
4,0] -7-undecene octylate and 1,
2,3,4-tetramethylimidazolinium octylate.

The mixing ratio of the blocked polyisocyanate (B) and the acrylic copolymer (A) in the solution-type or emulsion-type one-part acrylic pressure-sensitive adhesive of the present invention is (latent) NCO group / active hydrogen The equivalent ratio of the groups is usually (0.001 to 2.5) / 1, preferably (0.001
~ 2.0) / 1. When the equivalent ratio of NCO group / active hydrogen group is less than 0.001, cohesive strength is insufficient, and when it exceeds 2.5, tack and adhesive strength are reduced. Further, the amount of (C) to be added depends on the above (A) and (B)
Is usually 0.01 to 3.0% by weight, preferably 0.05 to 2% by weight, based on the total weight of. If the added amount of (C) is less than 0.01% by weight, the catalytic activity is weak and the regeneration of NCO groups due to dissociation of (B) becomes insufficient, and if it exceeds 3.0% by weight, unnecessary crosslinking reaction at low temperature. Progresses, and the storage stability of the one-pack type composition may decrease.

The solution-type or emulsion-type one-part acrylic pressure-sensitive adhesive composition of the present invention may contain, if necessary,
Various known additives can be contained as long as the effects of the present invention are not impaired. As various additives, tackifying resins (rosin, rosin derivative or hydrogenated product thereof, polyterpene resin, terpene phenol resin, xylene resin, styrene resin, cumarone / indene resin,
C5 petroleum resin, C9 petroleum resin, alicyclic hydrogenated petroleum resin, etc.), plasticizer (carboxylate ester represented by phthalate ester, paraffin chloride, etc.), coloring agent (titanium oxide, calcium carbonate, etc.) ), UV inhibitors (benzophenone UV inhibitors, etc.), antistatic agents (neutralized sulfonated polystyrene, etc.), fungicides (cuprous oxide, phenolic compounds, etc.), defoamers (alcohol,
Silicone compound).

The pressure-sensitive adhesive composition of the present invention can be applied to a substrate directly by a usual coating method (a method such as solution coating or emulsion coating) or by a transfer method. It can also be used in the form of a sheet as it is. The amount of application can be arbitrarily selected depending on the purpose of use of the coated product, but usually 1 to 500 g
/ M ² . Examples of the substrate that can be used include various plastic films or sheets such as polyethylene, polypropylene, polyethylene terephthalate, and soft polyvinyl chloride, resin plates, foams, papers, nonwoven fabrics, metal plates and foils, and wood. When a thermally sensitive plastic film, nonwoven fabric, or the like is used, a transfer method is preferable. The coated product is
Heating (usually 80 to 140 ° C.) by hot air or energy such as (near) infrared ray or high frequency to the dissociation temperature of the blocked polyisocyanate compound (B) to advance a crosslinking reaction, and further aging to complete crosslinking. Thereby, an adhesive processed product exhibiting sufficient adhesive properties can be obtained. The aging conditions are, for example, about 3 to 7 days at room temperature and about 12 to 24 hours under heating at 45 ° C.

[0038]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
In the following, "parts" indicates parts by weight and "%" indicates% by weight.

The test method used in the examples is as follows. Room temperature holding power (cohesion) test: stainless steel plate (SUS30)
4) A sample piece was stuck so as to have an adhesion area of 25 mm x 25 mm, and was reciprocated by 2 kg rollers once.
After leaving for 30 minutes in an atmosphere of ° C. and 65% RH, a static load of 1 kg was applied to the lower end of the test piece, and the shift distance (unit: mm) after 1 hour or the time until the test piece dropped (unit: Min) was measured. The smaller the value of the displacement distance and the longer the time until the test piece falls, the higher the cohesive strength (the more advanced the crosslinking).

Adhesive residue test: Stainless steel plate (SUS30
4) Attach a 25mm wide sample to 23 ° C x 65%
180 specified in JIS Z2307 under the condition of RH
゜ A peel test was performed to evaluate the state of the adhesive residue on the peeled surface.
The larger the adhesive residue, the more insufficient the crosslinking. Judgment criteria for adhesive residue state on 180 ° peeled surface No glue residue on entire peeled surface ----------------- 1 Adhesive residue on peeled end ---------------- Sparse glue on peeled surface Residual ------------ 3 Adhesive remains on the entire peeled surface --------

Production Example 1 [Production of Blocked Polyisocyanate Compound] 161 parts of diisodecyl phthalate was mixed with "polyisocyanate IPDI-T1890 / 100" [isophorone diisocyanate trimer, manufactured by Huls Japan Ltd.] 61
One part was dissolved at 105 to 130 ° C. under a nitrogen stream, 228 parts of methyl ethyl ketoxime was added, and the mixture was further reacted at 100 to 135 ° C. for 2 hours. The infrared absorption spectrum revealed that the isocyanate group had disappeared. It was confirmed. Thus, a blocked polyisocyanate compound (B-1) was obtained.

Production Example 2 [Production of quaternary ammonium / organic acid salt] Triethylamine (1 mol) was added to a stirring type autoclave.
Dimethyl carbonate (1.5 mol) and methanol (2.0 mol) as a solvent were charged.
The reaction was carried out for an hour to obtain a methanol solution of methyltriethylammonium methyl carbonate. Octylic acid (1 mol) was charged into the mixture, and by-product carbon dioxide and methanol were removed to remove methyltriethylammonium octylate (quaternary ammonium organic acid salt) (C-
1) was obtained.

EXAMPLE 1 5.5 parts of butyl acrylate and 3.9 of 2-ethylhexyl acrylate were placed in a four-necked corben equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen gas inlet tube.
Parts, 18.9 parts of ethyl acetate and 32.000 parts of cyclohexane.
4 parts were charged and heated to 75 ° C. Butyl acrylate 4
9.5 parts, 2-ethylhexyl acrylate 36.1
Parts, 2-hydroxyethyl methacrylate 1 part, acrylic acid 4 parts, 2,2′-azobis (2,4-dimethylvaleronitrile) 0.06 part and 2,2′-azobisisobutyronitrile 0.06 part Was mixed. The resulting monomer mixture was continuously dropped by a dropping funnel over 4 hours while blowing nitrogen into the kolben to perform radical polymerization. After completion of the dropwise addition, 0.21 part of 2,2′-azobis (2,4-dimethylvaleronitrile) was added to ethyl acetate 7.9.
The solution dissolved in the part was continuously added using a dropping funnel over 6 to 8 hours after the initiation of the polymerization. Further, after continuing the polymerization at the boiling point for 2 hours, toluene.
9 parts were added and made uniform. The viscosity of the resulting acrylic copolymer solution (A-1) was 4,250 cP at 30 ° C., the solid content concentration was 38.0%, and the weight average molecular weight (in terms of polystyrene) of the copolymer by GPC was about It was 330,000.
To 100 parts of the obtained acrylic copolymer solution (A-1), 0.1% of (B-1) prepared in Production Example 1 was used as a crosslinking agent.
3 parts of (C-1) prepared in Production Example 2 as a catalyst were added in 0.1 part.
19 parts, 26.7 parts of toluene was blended as a diluting solvent,
After uniform mixing, the mixture was coated on a polyethylene terephthalate film so as to have a thickness of 25 μm, and was applied at 120 ° C. × 1
Heated in 0 minutes. After leaving to cool, the coated sheet is cut into a predetermined width to prepare a test piece, and the test piece is used in accordance with the above-described test method to determine an adhesive property test [normal temperature holding force (cohesive force) test, adhesive force test, measurement of tack]. Was done. Table 1 shows the results. The viscosity at 30 ° C. of the coating liquid obtained by mixing with a B-type viscometer was 15 poise. After leaving the coating solution at room temperature for one month, the viscosity was measured.
The viscosity was 8 poise, and almost no increase in viscosity was observed.

Example 2 Vinyl acetate 12 was added to a four-necked kolben equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen gas introduction pipe.
Parts, butyl acrylate 3.8 parts, ethyl acetate 28.6
And 23.6 parts of cyclohexane were charged and the temperature was raised to 75 ° C. 72.7 parts of butyl acrylate, 8.5 parts of 2-ethylhexyl acrylate, 3 parts of acrylic acid and 0.125 part of 2,2′-azobisisobutyronitrile were mixed. The resulting monomer mixture was continuously dropped by a dropping funnel over 4 hours while blowing nitrogen into the kolben to perform radical polymerization. After dropping, 2,2'-
Using a dropping funnel, a solution of 0.175 part of azobisisobutyronitrile dissolved in 7.5 parts of ethyl acetate was divided into three times at 6, 7, and 9 hours after the start of polymerization. Added. After the polymerization was continued at the boiling point for 2 hours, 8.3 parts of ethyl acetate and 99.8 parts of toluene were added to make the mixture uniform. The solution of the obtained acrylic copolymer (A
The viscosity of -2) was 5,100 cP at 30 ° C., the solid content concentration was 37.0%, and the weight average molecular weight (polystyrene conversion) of the copolymer by GPC was about 410,000. To 100 parts of the obtained acrylic copolymer solution (A-2), 1.0 part of (B-1) prepared in Production Example 1 as a cross-linking agent, and 1.0 part of (C- 1) 0.19 parts,
23.3 parts of toluene was blended as a diluting solvent, and a test piece was prepared in the same manner as in Example 1 to perform an adhesive property test. Table 1 shows the results.

Comparative Example 1 100 parts of butyl acrylate and 1.7 parts of N-butoxymethyl acrylamide were placed in a four-necked colben equipped with a stirrer, thermometer, reflux condenser, dropping funnel and nitrogen gas inlet tube.
Parts, 1.7 parts of glycidyl methacrylate and 0.8 parts of benzoyl peroxide were dissolved in 270 parts of ethyl acetate. This was reacted at 70 ° C. for 7 hours while stirring in a nitrogen stream. The solution of the obtained acrylic copolymer (D-
Using only 1), a test piece was prepared in the same manner as in Example 1, and an adhesive property test was performed. The results are also shown in Table 1.

Comparative Example 2 The solution of the acrylic copolymer obtained in Example 2 (A-
2) 1.0 part of methoxymethylol melamine resin was added as a crosslinking agent to 100 parts, and a test piece was prepared in the same manner as in Example 1 to conduct an adhesive property test. The results are also shown in Table 1.

[0047]

[Table 3]

[0048]

The solution-type or emulsion-type one-part acrylic pressure-sensitive adhesive composition of the present invention can be prepared by using a quaternary ammonium organic acid salt as a dissociation catalyst for a blocked polyisocyanate compound. Compared with those, it is one-part and has excellent storage stability, and can be crosslinked at a relatively low temperature. Further, an adhesive processed product excellent in adhesive properties can be obtained. The solution-type or emulsion-type one-component acrylic pressure-sensitive adhesive composition of the present invention, which exhibits the above-described effects, is particularly suitable for light-weight adhesive labels, stickers, adhesive tapes, and tapes for fixing wiring in electric devices. It can be suitably used as a masking tape at the time of baking paint, a tape for sealing an electrolytic capacitor, and the like.

────────────────────────────────────────────────── ─── Continuation of the front page Examiner Koichiro Tanaka (56) References JP-A-58-109527 (JP, A) JP-A-5-17555 (JP, A) JP-A 9-137149 (JP, A) ( 58) Field surveyed (Int. Cl. ⁷ , DB name) C09J 1/00-201/10 CA (STN) REGISTRY (STN)

Claims (5)

(57) [Claims] 1. An alkyl (meth) acrylate having 4 to 12 carbon atoms in the alkyl group (a1).
5% by weight, 0.5 to 10% by weight of an unsaturated carboxylic acid or acid anhydride (a2) of the following (1) and, if necessary, 0 to 40% by weight of another polymerizable monomer (a3) as constituent units. A solution comprising a copolymer (A), a blocked polyisocyanate compound (B), and a catalyst comprising a quaternary ammonium organic acid salt (C) obtained from the following organic acid (2). And emulsion type one-part acrylic pressure-sensitive adhesive compositions. (1) Unsaturated carboxylic acid or acid anhydride selected from (meth) acrylic acid, crotonic acid, (anhydride) maleic acid, (anhydride) itaconic acid and (anhydride) fumaric acid (2) aliphatic monocarboxylic acid, fat Group polycarboxylic acids,
At least one organic acid selected from the group consisting of aromatic monocarboxylic acids, aromatic polycarboxylic acids, phenol compounds, sulfonic acid compounds and phosphoric acid compounds (C) is represented by the following general formula: [Wherein, R ^{1 to} R ³ are linear or branched, saturated or unsaturated hydrocarbon groups having 1 to 11 carbon atoms (provided that R ^{1 to} R ³
May form a heterocyclic ring via a C, O or N atom. ), And R ⁴ has 1 carbon atom
To 8 alkyl groups or aromatic hydrocarbon groups. X ^-
Represents an organic acid anion group. The composition according to claim 1, which is a quaternary ammonium organic acid salt represented by the formula: 3. A quaternary ammonium organic acid salt obtained by an anion exchange reaction between a quaternary ammonium carbonate obtained by reacting a tertiary amine and a carbonic acid diester with an organic acid. The composition according to claim 1. 4. The tertiary amine is trimethylamine,
Triethylamine, 1,5-diazabicyclo [4,3
0] -5-nonene, 1,8-diazabicyclo [5,4,
The composition according to claim 3, which is at least one member selected from the group consisting of 0] -7-undecene and 1,2,4-trimethylimidazoline. 5. A coated product obtained by applying the composition according to claim 1 to a substrate by solution coating or emulsion coating, and heating the coated product to a temperature higher than the dissociation temperature of the blocked polyisocyanate compound (B). A method of using a pressure-sensitive adhesive composition which forms a pressure-sensitive adhesive product by cross-linking.