JP2008266384A - Vinyl acetate-based adhesive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vinyl acetate-based adhesive having excellent adhesiveness, water resistance and mechanical characteristics, usable for woodwork use such as dressing plywood, flush plywood and furniture, paper and packaging material use such as corrugated cardboard, book binding, bag-making and paper box, construction use such as flooring material, plastic tile, wall paper and wall cloth, etc., capable of keeping the film-forming properties even in a low-temperature condition of 0-2°C at a cold region or in winter or the like, being an all-season type, and hardly causing environmental pollution and bad effects on a living body because of containing little VOC (volatile organic compound). <P>SOLUTION: The vinyl acetate-based adhesive comprises (A) a vinyl acetate-based resin emulsion and (B) a trialkyl citrate regulated so that the content of the trialkyl citate (B) may be 5-15 pts.wt. based on 100 pts.wt. solid component of the vinyl acetate-based resin emulsion (A). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vinyl acetate adhesive. More specifically, it is a vinyl acetate adhesive using a vinyl acetate resin emulsion. For example, for woodwork such as decorative plywood, flash plywood, furniture, and paper and packaging materials such as cardboard, bookbinding, bag making, paper boxes, etc. Used for construction of flooring materials, vinyl tiles, wallpaper, wall cloth, etc., especially excellent performance such as film-forming property, adhesiveness, water resistance, and mechanical properties under low temperature conditions of 0-2 ° C Have

  Conventionally, vinyl acetate resin emulsions have relatively good adhesion and weather resistance, and from the viewpoint of workability, cost, safety, etc., for example, for woodworking, paper / packaging materials, construction, etc. It has been used extensively as an adhesive.

  However, adhesives using a conventional type of vinyl acetate resin emulsion have a minimum film forming temperature (abbreviated as MFT) of about 20 ° C., so that the adhesive is made under low temperature conditions such as in cold districts and in winter. The film properties are inferior, the film forming speed is extremely slow, and the performance such as adhesiveness, water resistance, and mechanical properties is insufficient.

  Therefore, for example, dibutyl phthalate (DBP), diheptyl phthalate (DHP), phthalate is used for the purpose of lowering the minimum film-forming temperature (MFT) to 0 to 2 ° C. and enabling use under low temperature conditions. A method of blending a phthalate ester compound such as dimethyl acid (DMP) into a vinyl acetate resin emulsion as a so-called “film-forming aid” has been performed.

  Among the phthalate ester compounds, dibutyl phthalate (DBP) is mainly used for reasons such as odor and cost. DBP is usually 20 parts per 100 parts by weight of the solid content of the vinyl acetate resin emulsion. If not more than a part by weight is added, the minimum film-forming temperature (MFT) cannot be lowered to a low temperature range of 0 to 2 ° C. If DBP is added in such a large amount, the resin itself is excessively plasticized. As a result, the cohesive strength of the resin is excessively reduced, and there is a detrimental effect that the adhesive strength is lowered particularly at room temperature or high temperature.

  Furthermore, some of the phthalate-based compounds have been pointed out to be suspected of environmental hormones, and their use tends to be avoided in the industry. Such compounds are used as film-forming aids. Therefore, it has been desired to develop a vinyl acetate adhesive that has a low VOC (Volatile Organic Compound) and has almost no adverse effects on the environment and the living body.

  In order to improve such a problem, an adhesive comprising a vinyl acetate resin emulsion containing a polyethylene glycol alkyl ether benzoate as a film-forming auxiliary has been proposed. The film-forming temperature (MFT) can be lowered to a low temperature range of 0 to 2 ° C., can be appropriately plasticized, and can reduce the deterioration of adhesiveness, water resistance, mechanical properties due to plasticization (for example, (See Patent Document 1).

  However, the water-based adhesive obtained in Patent Document 1 is inferior in heat resistance and has high volatility of polyethylene glycol alkyl ether benzoates under high temperature conditions. It was never satisfactory in practical use.

  Moreover, the glass transition temperature formed by mix | blending an organic polyisocyanate compound with respect to the aqueous emulsion containing polyvinyl alcohol (PVA) and the vinyl copolymer resin which has a primary hydroxyl group and / or a carbonyl group in a molecule | numerator- A two-component adhesive composition having a temperature of 20 ° C. or less has been proposed, and the two-component adhesive composition contains 2,2,4-trimethyl 1,3-pentanediol diisobutyrate (TXIB) and has a good initial value. Adhesiveness and adhesion durability can be imparted, and it is highly safe as a plasticizer and has a low VOC. In particular, adhesion between plastic materials such as plastic films, and plastic materials, wood, paper, and inorganic plates It is suitable for adhesion with a porous material such as the above (for example, see Patent Document 2).

  However, the two-component adhesive composition obtained in Patent Document 2 is inferior in film-forming properties under low temperature conditions and contains TXIB, which has a relatively high volatility. Concerned and not satisfactory in practice.

JP 2000-80234 A JP 2005-15710 A

  The object of the present invention is excellent in performance such as film-forming property, adhesiveness, water resistance and mechanical properties under low temperature conditions of 0 to 2 ° C., and exhibits excellent performance even in harsh conditions such as cold regions and winter. The present invention relates to a vinyl acetate-based adhesive that is an all-season type that can be produced and that has a low VOC and has almost no adverse effects on environmental pollution or living organisms.

  More specifically, for example, used for construction of decorative plywood, flash plywood, woodwork such as furniture, paper and packaging materials such as cardboard, bookbinding, bag making, paper boxes, flooring, vinyl tile, wallpaper, wall cloth, etc. It is a vinyl acetate adhesive, can maintain excellent film-forming properties even under low temperature conditions of 0 to 2 ° C., has excellent performance such as adhesion, water resistance and mechanical properties, and has low VOC. Therefore, it is to provide a vinyl acetate-based adhesive that has almost no adverse effects on the environment and the living body.

  As a result of intensive research to solve the above problems, the present inventor has blended a small amount of vinyl acetate resin emulsion with a trialkyl citrate as a film-forming aid as compared to conventional film-forming aids. The vinyl acetate-based adhesive can maintain excellent film-forming properties even under low temperature conditions of 0 to 2 ° C., has excellent performance such as adhesion, water resistance, mechanical properties, and low VOC. As a result, the present inventors have found that there is almost no adverse effect on environmental pollution or living organisms and have completed the present invention.

  That is, the present invention is an adhesive comprising a vinyl acetate resin emulsion (A) and a trialkyl citrate (B), and the content of the trialkyl citrate (B) is a vinyl acetate resin emulsion. The vinyl acetate-based adhesive is characterized by being 5 to 15 parts by weight with respect to 100 parts by weight of the solid content of (B).

  The vinyl acetate-based adhesive of the present invention is unexpectedly prepared by using a trialkyl citrate in a vinyl acetate-based resin emulsion in a small amount as compared with a conventional film-forming aid. The film-forming temperature (MFT) can be lowered to a low temperature range of 0 to 2 ° C. to maintain excellent film-forming properties, and the vinyl acetate resin itself is appropriately plasticized to reduce the cohesive strength of the resin itself. Because it is an all-season type that has excellent adhesion, water resistance, mechanical properties, etc., can exhibit excellent performance even in harsh conditions such as cold regions and winter, and has low VOC There is almost no adverse effect on the environment and living organisms.

  The matters necessary for carrying out the present invention are described below.

  First, the vinyl acetate adhesive of the present invention comprises a vinyl acetate resin emulsion (A) and a trialkyl citrate (B).

  The vinyl acetate resin emulsion (A) used in the present invention can be obtained by emulsion polymerization of vinyl acetate alone or a mixture of one or more vinyl monomers copolymerizable with vinyl acetate.

  The vinyl acetate resin emulsion (A) is, for example, vinyl acetate alone or vinyl acetate in the presence of a polymerization initiator such as ammonium persulfate, potassium persulfate, or hydrogen peroxide using polyvinyl alcohol (PVA) as a protective colloid. It can be obtained by emulsion polymerization of a vinyl monomer copolymerizable with the polymer.

  Examples of the vinyl monomers copolymerizable with vinyl acetate include (meth) methacrylate (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and the like. ) Acrylic acid alkyl esters, glycidyl (meth) acrylate, vinyl propionate, vinyl versatate, ethylene, propylene, styrene, acrylonitrile, (meth) acrylic acid, (meth) acrylic acid amide, crotonic acid, maleic acid, anhydrous Examples include maleic acid, fumaric acid, itaconic acid, ethylene glycol mono (meth) acrylate, propylene glycol mono (meth) acrylate, ethylene glycol di (meth) acrylate, dibutyl fumarate, and fumaric acid half ester.

  The use amount of the copolymerizable vinyl monomer is preferably less than 50% by weight and more preferably in the range of 5 to 30% by weight with respect to 100% by weight of the total amount of vinyl acetate and the copolymerizable vinyl monomer. .

  The polyvinyl alcohol used as the protective colloid preferably has a saponification degree of 78 to 98 mol%. When the saponification degree of the polyvinyl alcohol is in the range of 78 to 98 mol%, the adhesive is excellent in low temperature stability, low temperature fluidity, initial adhesive force, and the like.

  The amount of polyvinyl alcohol used as the protective colloid is preferably in the range of 5 to 20% by weight with respect to the total weight of vinyl monomers such as vinyl acetate. If the usage-amount of the said polyvinyl alcohol is the range of 5 to 20 weight%, the viscosity of a reaction system will become moderate and it is excellent in the stability at the time of superposition | polymerization.

  The polymerization method of the vinyl monomer such as vinyl acetate is not particularly limited. For example, hydrogen peroxide is used as a polymerization initiator, and this is divided or continuously added, and a vinyl monomer such as vinyl acetate is appropriately used. A method of completing the emulsion polymerization by adding sequentially over a period of time, usually 3 to 5 hours, is suitable.

  In the emulsion polymerization, for example, any known emulsifier such as an anionic emulsifier, a cationic emulsifier, an amphoteric emulsifier, and a nonionic emulsifier can be used.

  Examples of the anionic emulsifier include alkyl sulfate ester salts, alkylbenzene sulfonate salts, fatty acid salts, polyoxyethylene alkyl ether sulfate ester salts, and the like;

Examples of the cationic emulsifier include alkylamine salts and quaternary ammonium salts;

Examples of the amphoteric emulsifier include alkylbetaines and alkylamine oxides;

Examples of the nonionic emulsifier include polyoxyethylene alkyl ether, polyoxyalkylene alkyl ether, sorbitan fatty acid ester, polyoxyethylene fatty acid ester and the like, and these emulsifiers are used in combination as long as they do not impair the object of the present invention. May be.

  Furthermore, a reactive emulsifier can also be used, for example, at least one hydrophilic group selected from the group consisting of a sulfonic acid metal base, a sulfonic acid ammonium base, a sulfinic acid metal base, a sulfinic acid ammonium base, and an ethylene oxide group; Those having both an ethylenically unsaturated group which is a reactive group are preferred.

  Examples of the reactive emulsifier include sodium styrene sulfonate, sodium vinyl sulfonate, Latemul S-180A (manufactured by Kao Corporation), Eleminol JS-2 (manufactured by Sanyo Chemical Co., Ltd.), Aqualon HS-10 (Daiichi Kogyo). Pharmaceutical Co., Ltd.), HS-1025 (manufactured by the company), KH-05 (manufactured by the company), KH-10 (manufactured by the company), Adekaria soap SE-10N (manufactured by Asahi Denka Kogyo Co., Ltd.) and the like. It is not limited to these.

  In the production of the vinyl acetate resin emulsion (A), for example, polymerization conditions such as polymerization temperature, polymerization time, and monomer addition method (for example, batch, split, drop, continuous) can be set as appropriate, and are not particularly limited.

  Next, the trialkyl citrate (B) used essentially in the present invention will be described below.

  The trialkyl citrate (B) can be obtained by an esterification reaction using citric acid and an aliphatic alcohol having a linear, branched or cyclic alkyl group as raw materials.

  Citric acid is a plant-derived raw material produced mainly from starch and the like by fermentation and the like, and there are anhydrides and hydrates, but both can be used in the present invention, and the production method is particularly limited. do not do.

  The aliphatic alcohol is preferably an aliphatic alcohol having a linear, branched or cyclic alkyl group having 2 to 8 carbon atoms.

  Examples of the aliphatic alcohol having a linear, branched or cyclic alkyl group having 2 to 8 carbon atoms include ethanol, 1-propanol, 1-butanol, 2-butanol, isobutyl alcohol, tert-butyl alcohol, 1- Pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, isopentyl alcohol, tert-pentyl alcohol, 3-methyl-2-butanol, neopentyl alcohol, 1-hexanol, 2-methyl- 1-pentanol, 4-methyl-2-pentanol, 2-ethyl-1-butanol, 1-octanol, 2-methylhexanol, cyclohexanol, cyclopentanol, allyl alcohol, crotyl alcohol, methyl vinyl methanol, etc. Can be mentioned. If the carbon number of the alkyl group of the aliphatic alcohol that is the reaction raw material of the trialkyl citrate (B) is in the range of 2 to 8, the volatility is moderate and the film forming property, adhesiveness, and water resistance are excellent. Moreover, since it has a low VOC, there is almost no adverse effect on the environment or the living body, which is preferable.

  Furthermore, in the present invention, an alcohol having an aromatic ring can be used as a reaction raw material for obtaining a trialkyl citrate (B), such as benzyl alcohol, α-phenylethyl alcohol, β-phenylethyl alcohol, and the like. Can be mentioned.

  Among the trialkyl citrates (B), tributyl citrate, tripropyl citrate, and triethyl citrate are preferable, and tributyl citrate is more preferable because better film-forming properties, adhesion, and water resistance can be obtained. .

  The content of the trialkyl citrate (B) is 5 to 15 parts by weight, preferably 7 to 13 parts by weight, based on 100 parts by weight of the solid content of the vinyl acetate resin emulsion (A). . If the content of the trialkyl citrate (B) is within such a range, the minimum film-forming temperature (MFT) is an appropriate low-temperature region of 0 to 2 ° C., and excellent film-forming properties can be obtained. Plasticization is possible, and excellent performance such as cohesive strength, adhesive strength, and mechanical properties can be obtained.

  Examples of a method for obtaining the vinyl acetate-based adhesive of the present invention by adding the trialkyl citrate (B) to the vinyl acetate-based resin emulsion (A) include citric acid in the vinyl acetate-based resin emulsion (A). A method in which trialkyl (B) is added in an amount within a predetermined range as described above and uniformly stirred is exemplified and is not particularly limited.

  The vinyl acetate adhesive of the present invention contains a trialkyl citrate (B) for obtaining a minimum film-forming temperature (MFT) of 0 to 2 ° C. with respect to the solid content of the vinyl acetate resin emulsion (A). Since the amount may be smaller than that of a conventional film-forming auxiliary, the vinyl acetate resin itself is not significantly plasticized, and the cohesive force due to the trialkyl citrate (B) is not significantly reduced. For this reason, when used as an adhesive, there is usually no significant decrease in adhesive strength or water resistance caused by the addition of a film-forming aid, and there is almost no odor generation due to volatile organic compounds. There is almost no adverse effect on

  Examples of the vinyl acetate adhesive of the present invention include fillers such as calcium carbonate, clay, talc, silica, and alumina, colorants such as titanium oxide, thickeners such as methylcellulose and carboxymethylcellulose, preservatives, and silanes. You may add well-known additives, such as an antifoamer, such as a compound and a fluorine-type compound, aqueous thermosetting resins, such as a urea resin, and metal powder, in the range which does not inhibit the objective of this invention.

  The vinyl acetate adhesive of the present invention is, for example, for woodwork such as decorative plywood, flash plywood and furniture, for paper and packaging materials such as cardboard, bookbinding, bag making, paper box, flooring, vinyl tile, wallpaper, wall cloth, etc. It can be applied to construction adhesives, etc., and has a minimum film-forming temperature (MFT) in the low temperature range of 0 to 2 ° C. Furthermore, it has performance such as adhesiveness, water resistance, mechanical properties, etc., and has a low VOC, so there is almost no adverse effect on the environment and living organisms.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the scope of the present invention is not limited only to these examples. In the following, unless otherwise specified, “%” means “% by weight” and “part” means “part by weight”. The measurement method and evaluation method used in the present invention are as follows.

[Method for measuring volatile content (%) of film-forming aid]
About 1 g of a film-forming aid sample was precisely weighed in a petri dish, the weight (g) after heating at 108 ° C. for 1 hour was measured, and the volatile content (%) was calculated from the following formula.
Volatile content (%) = (Sample amount before drying−Sample amount after drying) / Sample amount before drying

[Method for preparing adhesive evaluation sample]
The adhesive is cast on a glass plate using an applicator, and a film having a thickness of 0.4 mm after being dried at room temperature for 24 hours is prepared. The film tensile strength, the minimum film-forming temperature (MFT), and the compressive shear strength (normal state) ) Was measured according to the following method. The measurement results are shown in Table 1.

[Measurement method of minimum film-forming temperature (MFT) of adhesive]
The minimum film-forming temperature (MFT) was measured by a method according to the standard of vinyl acetate resin emulsion wood adhesive of JIS K 6804.

[Method for measuring film tensile strength of adhesive]
In accordance with the tensile test of JIS K 7113, the film was cut out into a No. 2 dumbbell, the tensile test was performed at a tensile speed of 200 mm / min, and the tensile strength was measured.

[Method of measuring compressive shear strength (normal state)]
The compression shear strength (normal state) was measured by a method according to the standard of the compression shear bond strength test method of the adhesive of JIS K 6852.

[Synthesis Example 1] Synthesis of vinyl acetate resin emulsion (A1) In a reactor equipped with a stirrer, a thermometer and a dropping funnel, 135 parts of water and Gohsenol GH-17 (polyvinyl alcohol (PVA), manufactured by Nippon Synthetic Chemical Co., Ltd.) ) 7 parts and 4 parts of Gohsenol GL-05 (PVA, manufactured by Nippon Synthetic Chemical Co., Ltd.) were added, stirred and dispersed in water to prepare a dispersion. Next, this dispersion was heated to an internal temperature of 80 ° C., and held at the internal temperature of 80 ° C. for 1 hour to dissolve PVA to obtain a PVA aqueous solution. Next, this aqueous PVA solution was cooled to an internal temperature of 70 ° C., and 5 parts of vinyl acetate and 0.2 part of ammonium persulfate as a polymerization initiator were added thereto for initial polymerization. Thereafter, the internal temperature was raised to 80 ° C., and the reaction was carried out while dropping 95 parts of vinyl acetate and 0.4 part of ammonium persulfate separately over 4 hours. After completion of dropping, the reaction solution was further stirred at an internal temperature of 80 ° C. for 1 hour to obtain a vinyl acetate resin emulsion (A1) having a solid content of 45% by weight.

[Synthesis Example 2] Synthesis of trialkyl citrate (B1) 500 parts of citric acid (using anhydride), 751 parts of 1-butanol and 7 parts of paratoluenesulfonic acid (PTS) were mixed with a thermometer, a stirrer, a reflux condenser and The mixture was charged into a two-necked flask with an internal volume of 2 liters equipped with a decanter and subjected to esterification while dehydrating with stirring at an internal temperature of 120 ° C. When the acid value of the reaction product reached 3.0 mgKOH / g, Excess 1-butanol was distilled off under reduced pressure. Subsequently, the residue after distilling was transferred to a separating funnel, neutralized with an aqueous sodium hydroxide solution, and then washed with water three times to obtain a trialkyl citrate (B1). The volatile content of trialkyl citrate (B1) was 2.0%.

[Synthesis Example 3] Synthesis of trialkyl citrate (B2) 500 parts of citric acid (using anhydride), 467 parts of ethanol and 9.7 parts of PTS were added with a thermometer, stirrer, reflux condenser and decanter 2 The reaction mixture was charged into a liter four-necked flask and dehydrated with stirring at an internal temperature of 80 ° C. When the acid value of the reaction product reached 4.1, excess ethanol was distilled off under reduced pressure. Subsequently, the residue after the distillation was transferred to a separatory funnel, neutralized with an aqueous sodium hydroxide solution, and then washed with water three times to obtain a trialkyl citrate (B2). The volatile content of trialkyl citrate (B2) was 4.9%.

[Synthesis Example 4] Synthesis of trialkyl citrate (B3) 400 parts of citric acid (using anhydride), 1050 parts of 2-ethylhexanol and 0.072 part of tetraisopropyl titanate (TIPT) were thermometer, stirrer and reflux cooled. In a four-necked flask with an internal volume of 2 liters equipped with a kettle and a decanter, the mixture was dehydrated with stirring at an internal temperature of 200 ° C., and when the acid value of the reaction product became 1.1, excess 2-ethylhexanol was distilled off under reduced pressure. Subsequently, the residue after the distillation was transferred to a separatory funnel, neutralized with an aqueous sodium hydroxide solution, and then washed with water three times to obtain a trialkyl citrate (B3). The volatile content of trialkyl citrate (B3) was 0.1%.

[Examples 1-3]
As shown in Table 1, as Examples 1 to 3, the trialkyl citrate obtained in Synthesis Examples 2 to 4 (100 parts by weight of the solid content of the vinyl acetate resin emulsion (A1) obtained in Synthesis Example 1 was used. After adding a predetermined amount of each of (B1) to (B3), the mixture was stirred at 1000 rpm for 5 minutes at room temperature using a chemical mixer, and then the vinyl acetate adhesive (X1) to (X1) to ( X3) was obtained. The evaluation results are shown in Table 1.

[Comparative Examples 1-6]
As shown in Table 1, when the adhesive (Y1) was obtained using only the vinyl acetate resin emulsion (A1) as Comparative Example 1, the blending amount of trialkyl citrate (B1) in Example 1 as Comparative Example 2 Is changed from 10 parts by weight to 3 parts by weight, and an adhesive (Y2) is obtained, and as Comparative Example 3 (A1), 10 parts of dibutyl phthalate (DBP) is used to obtain an adhesive (Y3) In Comparative Example 4, when 20 parts of DBP was used in (A1) to obtain an adhesive (Y4), 10 parts of tetraethylene glycol 2-ethylhexyl ether benzoate (TEGEHE) was used in (A1) as Comparative Example 5. As a comparative example 6, 20 parts of 2,2,4-trimethyl 1,3-pentanediol diisobutyrate (TXIB) was used as (A1) to obtain an adhesive (Y6). If you went. The evaluation results are shown in Table 1.

Note 1) In Table 1, the vinyl acetate resin emulsion (A1) used in Synthesis Example 1 was used.
Note 2) In Table 1, the film-forming aids used for evaluation are as follows.
(B1); Tributyl citrate (B2); Triethyl citrate (B3); Tri-2-ethylhexyl citrate DBP; Dibutyl phthalate TAGEHE; Tetraethylene glycol 2-ethylhexyl ether benzoate TXIB; 2,2,4-trimethyl 1,3-pentanediol diisobutyrate

  From Table 1, the vinyl acetate adhesive of the present invention is unexpectedly obtained by adding a small amount of trialkyl citrate as a film-forming aid to a vinyl acetate resin emulsion. The minimum film-forming temperature (MFT) of the emulsion can be lowered to a low temperature range of 0 to 2 ° C., and excellent film-forming properties can be maintained. Moreover, excessive plasticization of the vinyl acetate resin itself is suppressed, and the resin itself It can be seen that there is little reduction in cohesive force, excellent performance such as adhesiveness, water resistance, mechanical properties, etc., and low VOC results in almost no environmental pollution or adverse effects on living organisms.

  The vinyl acetate adhesive of the present invention is, for example, for woodwork such as decorative plywood, flash plywood and furniture, for paper and packaging materials such as cardboard, bookbinding, bag making, paper box, flooring, vinyl tile, wallpaper, wall cloth, etc. It can be applied to construction adhesives, etc., and has a minimum film-forming temperature (MFT) in the low temperature range of 0 to 2 ° C., so it can maintain excellent film-forming properties even in low-temperature conditions such as in cold regions and in winter. Furthermore, it has performance such as adhesiveness, water resistance, mechanical properties, etc., and has a low VOC, so there is almost no adverse effect on the environment and living organisms.

Claims (4)

An adhesive comprising a vinyl acetate resin emulsion (A) and a trialkyl citrate (B), wherein the content of the trialkyl citrate (B) is a solid content of the vinyl acetate resin emulsion (A). A vinyl acetate-based adhesive, characterized by being 5 to 15 parts by weight with respect to 100 parts by weight. The vinyl acetate adhesive according to claim 1, wherein the alkyl group of the trialkyl citrate (B) has a carbon number of 2 to 8. The vinyl acetate adhesive according to claim 1 or 2, wherein the trialkyl citrate (B) is tributyl citrate. The content of the trialkyl citrate (B) is 7 to 13 parts by weight with respect to 100 parts by weight of the solid content of the vinyl acetate resin emulsion (A). Vinyl acetate adhesive.