JPH09137149A - Hot-melt type acrylic pressure-sensitive adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot-melt type acrylic pressure-sensitive adhesive which has a low curing initiation temp. by comprising: an acrylic copolymer comprising particular components; a blocked polyisocyanate; and a catalyst comprising a quaternary ammonium organic acid salt. SOLUTION: A 4-12C alkyl (meth)acrylate such as butyl acrylate in an amt. of 50 to 99.5wt.% (hereinafter referred to as '%'), 0.5 to 10% α,β-unsated. carboxylic acid such as acrylic acid, and 0 to 40% polymerizable monomer such as 2-ethylhexyl acrylate, are copolymerized to prepare an acrylic copolymer A having a wt.-average mol.wt. of about 5,000 to 1,000,000. The copolymer A, a blocked isocyanate compd. B in an amt. of an NCO group to active hydrogen group equivalent ratio of about (0.01 to 2.5):1, and a quaternary ammonium org. acid salt catalyst represented by the formula (wherein R<1> to R<3> represent a 1-11C hydrocarbon; and R<4> represents a 1-8C alkyl or the like) such as methyltriethylammonium octylate, in an amt. of about 0.01 to 3.0% based on the total amt. of the copolymer A and the compd. B are mixed together to prepare a hot-melt type acrylic pressure-sensitive adhesive compsn.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a hot-melt pressure-sensitive adhesive composition. More specifically, the present invention relates to a hot-melt type acrylic pressure-sensitive adhesive composition suitable for an adhesive label, a sticker, an adhesive tape for light packaging.

[0002]

2. Description of the Related Art Conventionally, as a catalyst used for lowering the dissociation temperature of a blocked polyisocyanate compound used as a cross-linking agent for a hot-melt type acrylic pressure-sensitive adhesive and imparting low temperature curability, an organic metal is used. Tertiary amines such as (heavy metal) catalysts (for example, zinc octylate, lead octylate, tin octylate, etc.), cycloamidines (1,8-diazabicyclo [5,4,0] -7-undecene, etc.), or their A catalyst such as an organic acid salt is known (for example, JP-A-58-34878).

[0003]

However, the one using the above-mentioned organometallic (heavy metal) catalyst becomes a pollution source such as water pollution due to the heavy metal generated from the catalyst;
In the case of using the catalyst of the tertiary amine or the salt thereof, the effect of imparting the low temperature dissociation property of the blocked polyisocyanate compound is insufficient; and the like.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above problems, and as a result, found a catalyst which is excellent in a low-temperature dissociation-providing effect of a blocked polyisocyanate compound and does not become a pollution source. The present invention has been reached. That is, in the present invention, as a constituent unit, an alkyl group having 4 to 12 carbon atoms (meth) acrylic acid alkyl ester (a1) 50 to 99.5% by weight, α, β-unsaturated carboxylic acid (a2) 0. A copolymer (A) obtained by copolymerizing 5 to 10 parts by weight and 0 to 40% by weight of another polymerizable monomer (a3), a blocked polyisocyanate compound (B), and a quaternary ammonium organic compound. The present invention relates to a hot-melt type acrylic pressure-sensitive adhesive composition, which comprises a catalyst comprising an acid salt (C).

The (meth) acrylic acid alkyl ester (a1) having 4 to 12 carbon atoms of the alkyl group constituting the copolymer (A) in the present invention has, for example, 4 to 1 carbon atoms.
(Meth) acrylate from aliphatic alcohol 2 [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 [cyclohexyl (meth) acrylate etc.] from alicyclic alcohol, (meth) acrylate [benzyl (meth) acrylate etc.] from aromatic alcohol and two or more of these A mixture of Of these, particularly preferred are n-butyl acrylate, 2-ethylhexyl acrylate and mixtures thereof.

Examples of the α, β-unsaturated carboxylic acid (a2) include monobasic acids such as (meth) acrylic acid and crotonic acid,
Examples thereof include polybasic acids such as maleic acid, itaconic acid and fumaric acid or acid anhydrides thereof, and monoalkyl esters of these polybasic acids. Of these, preferred are acrylic acid, methacrylic acid, maleic anhydride and itaconic acid, and particularly preferred is acrylic acid.

The other polymerizable monomer (a3) copolymerizable with (a1) and (a2) includes a polymerizable monomer (a3-1) having a reactive functional group and a reactive functional group. The polymerizable monomer (a3-2) which does not have a group is mentioned.
Examples of the (a3-1) include a polymerizable monomer having a hydroxyl group [2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, etc.], amide Group-containing polymerizable monomer [(meth) acrylamide, etc.], epoxy group-containing polymerizable monomer [glycidyl (meth) acrylate, etc.], amino group-containing polymerizable monomer [N, N-dimethylamino] Ethyl (meth) acrylate, etc.], polymerizable monomers having a methylol group [N-methylol acrylamide, etc.], polymerizable monomers having a sulfonic acid group [sodium alkylallyl sulfosuccinate, etc.], polymerization having a phosphoric acid group And a monomer such as a phosphoric acid ester of 2-hydroxyethyl acrylate.

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

Among the above-mentioned other polymerizable monomers (a3), preferable ones are the polymerizable monomers having a hydroxyl group in (a3-1), and particularly preferable one is hydroxyethyl ( (Meth) acrylate. Further, in (a3-2), an aromatic polymerizable monomer, and particularly preferable one is styrene.

The above-mentioned other polymerizable monomer (a3) is
Two or more kinds can be used as a mixture.

The amount of (a1) constituting the polymer (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 tackiness will be reduced, and if it exceeds 99.5% by weight, cohesive force will be reduced and the pressure-sensitive adhesive will not function.

The amount of (a2) is usually 0.5 to 10% by weight,
It is preferably 1 to 8% by weight, particularly preferably 2 to 6% by weight. If the amount of (a2) is less than 0.5% by weight, the cohesive force will decrease, and if it exceeds 10% by weight, the adhesive force and tack at room temperature will decrease.

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

(A1), (a2) and (a) if necessary
The copolymer comprising 3) is produced by a known polymerization method (bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization, etc.) by a known polymerization initiator (azobisisobutyronitrile, azobisisovaleronitrile). And azo-based polymerization initiators such as benzoyl peroxide, di-t-butyl peroxide, and lauryl peroxide-based polymerization initiators).

The molecular weight of the copolymer consisting of (a1), (a2) and optionally (a3) in the present invention is usually 5,000 as determined by gel permeation chromatography (GPC) method.
0 to 1,000,000, preferably 50,000 to 1,0
00,000, more preferably 200,000 to 1.0
It is 00000. When the weight average molecular weight is less than 5,000, the cohesive force is insufficient, and when it exceeds 1,000,000, the melt viscosity becomes high and the handling becomes difficult.

Examples of the organic polyisocyanate constituting the blocked polyisocyanate compound (B) in the present invention include low-molecular polyisocyanates (b1) and free isocyanates (NC) from polyols and (b1).
Urethane prepolymers (b2) having O) groups and mixtures thereof. Examples of the low molecular weight polyisocyanates (b1) include aliphatic polyisocyanates [eg hexamethylene diisocyanate (HDI), lysine diisocyanate, etc.]; alicyclic polyisocyanates [dicyclohexylmethane diisocyanate]. -To (hydrogenated MD
I), isophorone diisocyanate (IPDI), cyclohexane diisocyanate (CHDI), hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, etc.]; aromatic polyisocyanate [eg. Tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), naphthylene diisocyanate
(NDI), xylylene diisocyanate (XD)
I), α, α, α, α'-tetramethylxylylene diisocyanate (TMXDI) and the like]; modified isocyanate (isocyanurate, buret, uretdione, carbodiimide and the like]; and these 2
Mixtures of more than one species. Further, as the polyols constituting the urethane prepolymer (b2) having a free NCO group, low molecular weight polyols (ethylene glycol, propylene glycol, butanediol, glycerin, trimethylolpropane, castor oil, etc.), polyether polyols [above-mentioned Low molecular weight polyol, alkylene oxide (ethylene oxide, propylene oxide, etc.) adduct of amines (alkanolamine, ethylenediamine, diethylenetriamine, aminoethylpiperazine, etc.)], polyester polyol [low molecular weight polyol or polyether polyol and polycarboxylic acid (adipic acid) , Terephthalic acid, etc.) and condensed polyester polyols] and mixtures of two or more thereof.

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

The prepolymerization reaction is usually carried out in the presence of a solvent. Examples of the solvent include aromatic hydrocarbon solvents (toluene, xylene, trimethylbenzene, etc.); ester solvents [ethyl acetate, butyl acetate, DBE
(A mixture of dimethyl succinate, dimethyl glutarate and dimethyl adipate), etc.]; ether system (cellosolve acetate, carbitol acetate etc.); ketone system (methyl ethyl ketone, cyclohexanone etc.); and two or more of these Mention may be made of mixed solvents.

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 10,000, 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 [eg ketoxime such as acetoxime, methylethylketoxime (MEK oxime), methylisobutylketoxime (MIBK oxime)]; lactam compounds ( ε-caprolactam, δ-valerolactam, γ
-Butyrolactam etc.); phenol compound (eg phenol, m-cresol, xylenol etc.); active methylene compound [eg malonic acid diester (diethyl malonate etc.), acetylacetone, acetoacetate ester (ethyl acetoacetate etc.) ) And the like]; alcohol compounds (for example, methanol, ethanol, n-butanol and the like); hydroxyl group-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 (for example, imidazole-
Imide compounds (eg, succinimide, phthalimide, etc.); and mixtures of two or more of these.

Of these, preferred are oxime compounds, lactam compounds and phenol compounds,
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 groups 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 linear or branched, saturated or unsaturated hydrocarbon groups having 1 to 11 carbon atoms (R ¹
Any two of R ³ to R ³ may form a heterocycle via a C, O or N atom. R ⁴ represents an alkyl group having 1 to 8 carbon atoms or an aromatic hydrocarbon group. X represents an organic acid group. In the general formula (1), when R ^{1 to} R ⁴ are all the same, the crystallinity of the obtained (C) is high, so that the solubility in the resin component and the solvent is lowered, and there is a problem that it is difficult to handle during work. Occurs. Therefore, it is desirable that at least one of R ^{1 to} R ⁴ has a different number of carbon atoms.

The manufacturing method of (C) is, for example, the fourth method.
Examples include a method of reacting a quaternary ammonium hydroxide with an organic acid and a method of anion-exchange reaction of 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 step.

Examples of the carbonic acid diester used in the above-mentioned production method include dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, dipropyl carbonate and the like. Particularly preferred is dimethyl carbonate having a small number of alkyl group carbon atoms.

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

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. Carbon dioxide produced as a by-product and, if necessary, alcohol may be added to the reaction system. The organic salt of quaternary ammonium salt (C) can be obtained by appropriately removing After the reaction, if necessary, the reaction solvent may be distilled off and used as it is, or
Or aqueous solution or 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 with respect to 1 mol of (a).
˜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 the obtained (C) is 6.5 to 7.5.

As the tertiary amine constituting (C),
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, etc.]; and mixtures of two or more thereof.
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 acid constituting (C) includes aliphatic monocarboxylic acids [formic acid, acetic acid, octylic acid, 2-ethylhexanoic acid, etc.]; aliphatic polycarboxylic acids (oxalic acid, malonic acid, succinic acid, glutaric acid) Acid, adipic acid, etc.); Aromatic monocarboxylic acid (benzoic acid, toluic acid, ethylbenzoic acid, etc.); Aromatic polycarboxylic acid (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.);
Phosphoric acid compounds and the like. The organic acid is one or two
It can be used as a mixture of more than one species. 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 [5,5].
4,0] -7-undecene octylate and 1,
2,3,4-tetramethylimidazolinium octylate.

Regarding the blending ratio of the blocked polyisocyanate (B) and the acrylic copolymer (A) in the hot-melt acrylic pressure-sensitive adhesive of the present invention, the equivalent ratio of NCO group / active hydrogen group is usually (0. The amount is 01 to 2.5) / 1, preferably (0.05 to 2.0) / 1. NCO group /
If the equivalent ratio of active hydrogen groups is less than 0.01, the cohesive force is insufficient, and if it exceeds 2.5, the tackiness is reduced.
The amount of (C) added is usually 0.01 to 3.0% by weight, preferably 0.05 to 2% by weight, based on the total weight of (A) and (B). Addition amount of (C) is 0.0
If it is less than 1% by weight, the catalytic activity is weak and regeneration of the isocyanate group due to dissociation of (B) becomes insufficient, resulting in 3.0% by weight.
When it exceeds the above value, an unnecessary crosslinking reaction proceeds at a lower temperature, so that the viscosity of the composition increases during melt mixing or coating of (A), (B) and (C), and the mixing or coating is not performed. It can be difficult.

The hot-melt acrylic pressure-sensitive adhesive composition of the present invention may contain various known additives, if necessary, within a range not impairing the effects of the present invention. As various additives, tackifying resins (rosin, rosin derivatives or hydrogenated products thereof, polyterpene resins, terpene phenol resins, xylene resins, styrene resins,
Coumaron / indene resin, C5 petroleum resin, C9 petroleum resin, alicyclic hydrogenated petroleum resin, etc.), plasticizer (carboxylic acid ester represented by phthalic acid ester, chlorinated paraffin, etc.), colorant (oxidation) Titanium, calcium carbonate, etc., anti-UV agent (benzophenone-based anti-UV agent, etc.), antistatic agent (neutralized product of sulfonated polystyrene, etc.), antifungal agent (cuprous oxide, phenolic compound, etc.), antifoaming agent (Alcohol, silicone compound, etc.) and the like.

The pressure-sensitive adhesive composition of the present invention can be applied to a substrate directly or by a transfer method by an ordinary coating method, that is, a method such as hot melt coating. Also, it can be used as it is in a sheet form. The coating amount can be arbitrarily selected according to the purpose of use of the coated product, but is usually 1 to 500 g / m.
² Examples of the base material that can be used include polyethylene, polypropylene, polyethylene terephthalate, various plastic films or sheets such as soft polyvinyl chloride, resin plate, foam, paper, non-woven fabric, metal plate and foil,
Wood etc. can be mentioned. Of these, the transfer method is preferable when using a thermally sensitive plastic film, non-woven fabric, or the like. The melt-coated product is heated to a temperature not lower than the dissociation temperature of the blocked isocyanate compound (B) by the energy of hot air or (near) infrared rays, high frequency, etc., to cause a crosslinking reaction, and further undergoes aging for complete crosslinking. By doing so, it becomes an adhesive processed product that exhibits sufficient adhesive properties. The aging conditions are, for example, about 3 to 7 days at room temperature and 12 to 12 hours under heating at 70 ° C.
It is about 24 hours. The above material coated with the hot-melt acrylic pressure-sensitive adhesive composition of the present invention can be suitably used as an adhesive label, a sticker, various adhesive tapes and the like.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. In the following, "parts" indicates parts by weight and "%" indicates% by weight.

The test method used in this example is as follows. Room temperature retention (cohesion) test: Stainless steel plate (SUS30
Attach the sample piece to 4) so that the adhesive area is 25 mm × 25 mm, and press it back and forth once with a 2 kg roller.
After leaving it in an atmosphere of ℃ × 65% RH for 30 minutes, a static load of 1 kg is 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 falls (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 force (the progress of crosslinking).

Adhesion test: Stainless plate (SUS30
A sample piece of 25 mm width is attached to 4) and 23 ° C x 65%
180 specified in JIS Z2307 under RH conditions
° Peeling test (unit: g) was performed and the adhesive strength (unit: kg /
cm ² ) and the state of adhesive residue on the peeled surface were evaluated. It is indicated that the larger the amount of adhesive residue, the insufficient the crosslinking. 180 ° Judgment standard of adhesive residue on peeling surface No adhesive residue on the entire peeling surface ------------- Adhesive residue on the peeling edge ---------- There is residue ------ Glue remains on the entire peeled surface ---------

Measurement of tack: J. C. under an atmosphere of 23 ° C. × 65% RH. Tack was measured by the Dow method. The smaller the value is, the more the crosslinking is advanced.

[0042]

【Example】

Synthesis Example 1 [Production of Acrylic Copolymer] 47 parts of ethyl acetate was charged into a 4-neck Kolben equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a nitrogen gas inlet tube, and the temperature was raised to 75 ° C. Butyl acrylate 40
Parts, 2-ethylhexyl acrylate 57 parts, acrylic acid 3 parts and 2,2′-azobis (2,4-dimethylvaleronitrile) 0.07 parts 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 completion of the dropwise addition, a solution of 0.3 part of 2,2′-azobis (2,4-dimethylvaleronitrile) dissolved in 5.9 parts of ethyl acetate was added to the solution using a dropping funnel, and 5 to 9 Continuously added over time. Further, the polymerization was continued at the boiling point for 2 hours, and then the solvent was removed. The obtained acrylic copolymer (A-1) has a melt viscosity of 366,000 cP at 130 ° C., a solid content concentration of 99.7%, and a weight average molecular weight (polystyrene conversion) of the copolymer by the GPC method of about 51. It was good.

Synthesis Example 2 [Production of quaternary ammonium / organic acid salt] Triethylamine (1 mol) was added to a stirring 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 added to this product, and carbon dioxide gas and methanol produced as by-products were removed to remove methyltriethylammonium octylate (quaternary ammonium organic acid salt) (C-
1) was obtained.

Synthesis Example 3 [Production of Blocked Polyisocyanate Compound] 161 parts of diisodecyl phthalate "Polyisocyanate IPDI-T1890 / 100" [isophorone diisocyanate trimer, manufactured by Huls Japan KK] 61
1 part was dissolved in a nitrogen stream at 105 to 130 ° C., then 228 parts of methyl ethyl ketoxime was added, and after reacting at 100 to 135 ° C. for 2 hours, the isocyanate group disappeared by infrared absorption spectrum. It was confirmed. Thus, a blocked polyisocyanate compound (B-1) was obtained.

Examples 1 to 4 The copolymer (A-1) prepared in Synthesis Example 1 and the blocked polyisocyanate compound prepared in Synthesis Example 3 as a cross-linking agent (in the blending ratio (weight) shown in Table 1) B-1), as a catalyst, the methyltriethylammonium octylate salt (C-1) prepared in Synthesis Example 2 was blended under heat melting at 100 to 110 ° C., and after uniform mixing, the film thickness was formed on the polyethylene terephthalate film. To 25 μm, heated under the conditions shown in Table 2, and further cured at 45 ° C. for 3 days. This coated sheet was cut into a predetermined width to give a test piece, and an adhesive property test [room temperature retention (cohesion) test, adhesion test, tack measurement] was performed according to the test method described above. . Table 3 shows the results.

Comparative Examples 1 to 4 Instead of the catalyst (C-1) shown in Table 1, 1,8-diazabicyclo [5,4,0] -7-undecene octyl acid salt (a salt of a tertiary amine) was used. ) [Product Name: "U-CAT SA
109 ", manufactured by San-Apro Co., Ltd.] (D-1),
Test pieces were prepared in the same manner as in Examples 1 to 4 and subjected to an adhesive property test. The results are also shown in Table 3.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

[Table 3]

[0050]

EFFECTS OF THE INVENTION The hot-melt acrylic pressure-sensitive adhesive composition of the present invention uses a conventional chloramidine (1,8) by using a quaternary ammonium organic acid salt as a dissociation catalyst for a blocked polyisocyanate compound. -Comparison with a catalyst using a tertiary amine such as diaza-bicyclo [5,4,0] -7-undecene) or a salt thereof or the like can lower the curing initiation temperature (dissociation temperature). It is also possible to crosslink in a short time. Further, it is possible to obtain an adhesive processed product which is excellent in terms of adhesive properties. Further, unlike the case of using an organometallic catalyst, there is no concern about environmental pollution such as water pollution due to heavy metal derived from the catalyst, and the safety is high. From the above effect, the heat-melting acrylic pressure-sensitive adhesive composition of the present invention is an adhesive label for light packaging,
It can be suitably used for industrial purposes such as stickers and various adhesive tapes.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshishige Matsunaga 1 1-11, Hitotsubinohonmachi, Higashiyama-ku, Kyoto Sanyo Chemical Industry Co., Ltd.

Claims (5)

[Claims] 1. A constitutional unit comprising a (meth) acrylic acid alkyl ester (a) having an alkyl group with 4 to 12 carbon atoms.
1) Copolymerized with 50 to 99.5% by weight, 0.5 to 10 parts by weight of α, β-unsaturated carboxylic acid (a2) and 0 to 40% by weight of another polymerizable monomer (a3). Copolymer (A) and blocked polyisocyanate compound (B)
And a catalyst comprising a quaternary ammonium organic acid salt (C), a heat-melting acrylic pressure-sensitive adhesive composition. 2. (C) is the following general formula: [In the formula, R ^{1 to} R ³ are linear or branched, saturated or unsaturated hydrocarbon groups having 1 to 11 carbon atoms (any two of R ^{1 to} R ³ are C, O or N atoms). A hetero ring may be formed via R.), and R ⁴ represents an alkyl group having 1 to 8 carbon atoms or an aromatic hydrocarbon group. X represents an organic acid group. ] The composition of Claim 1 which is a quaternary ammonium organic acid salt shown by these. 3. (C) is 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, and an organic acid. Item 1. The composition according to Item 1 or 2. 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 selected from the group consisting of [0] -7-undecene and 1,2,4-trimethylimidazoline. 5. The organic acid constituting (C) is at least one selected from the group consisting of an aliphatic monocarboxylic acid, an aliphatic polycarboxylic acid, an aromatic monocarboxylic acid and an aromatic polycarboxylic acid. Item 5. The composition according to any one of items 1 to 4.