JP5243055B2 - Water-based adhesive composition - Google Patents

Description

  The present invention relates to a water-based adhesive, and more particularly to a water-based adhesive composition that exhibits excellent water-resistant adhesion without being hot-pressed and can be suitably used mainly for applications such as furniture and woodworking.

  In general, formaldehyde resins, that is, urea-formaldehyde resins, resorcinol-formaldehyde resins, melamine-formaldehyde resins, and the like are widely used as adhesives for wood from the viewpoint of water resistance and heat resistance. However, adhesives containing these formaldehyde resins release toxic formalin from the adhesive layer inside the laminated plywood into the atmosphere during the manufacturing process of the plywood or after commercialization. There was a problem. In addition, these formaldehyde resin adhesives, for example, after 30 hours at 30 ° C., the viscosity increases with the gelation of the adhesive, which may cause a decrease in coating properties or adhesive strength. But there are still challenges.

  In recent years, due to revisions to the Building Standards Law, the concentration of formaldehyde emitted from building materials used in residential buildings and the like into the atmosphere has been severely restricted, and research on adhesives that do not contain formaldehyde has been actively conducted. Yes. For example, as an adhesive capable of improving water resistance and heat resistance without using formaldehyde, an aqueous solution or aqueous emulsion containing polyvinyl alcohol is mixed with an isocyanate compound and a thickener or a filler capable of reacting with the isocyanate compound. A water-resistant adhesive formed by blending an agent is disclosed (for example, see Patent Document 1). In addition, a two-component fractional coating type adhesive composition in which polyvinyl alcohol containing an acetoacetyl group in the molecule and an isocyanate compound are blended as the liquid A, and an aqueous solution containing a hydrazine compound and a glycidylamine type epoxy resin are blended as the liquid B. The thing is proposed (for example, refer patent document 2).

Moreover, recently, an adhesive composition for wood containing a polyamide epoxy resin (for example, see Patent Document 3) and an aqueous adhesive composition containing a tetrafunctional epoxy compound (for example, Patent Document 4 and Patent Document 5). Adhesive compositions containing various epoxy compounds have been proposed.
Japanese Patent Publication No. 51-30576 (Claim 1) JP-A-6-256748 (Claim 1) JP-A-2001-003022 (Claim 1) JP-A-2005-087701 (Claim 1) JP-A-2005-089702 (Claim 1)

  However, the invention described in Patent Document 1 has little change in viscosity due to high temperature and good apparent coatability, but the adhesive adheres to the iron press during pressing in the bonding process, and the adhesive is removed. There is a problem of causing trouble. In addition, the invention described in Patent Document 2 has excellent points such as improvement in water-resistant adhesive strength and shortening of the pressing time, but on the other hand, it is attempted to use mixed liquid A and liquid B at room temperature (20 ° C.). In this case, a strong interaction occurs immediately between the acetoacetyl group contained in the molecule of the polyvinyl alcohol in the liquid A and the hydrazine compound in the liquid B, resulting in gelation. Therefore, one liquefaction is difficult. Further, the inventions described in the above Patent Documents 3 to 5 can be suitably used for bonding wood mainly composed of hot pressure such as plywood. However, particularly with cold pressure, the expression of water-resistant adhesive strength is not sufficient. For this reason, it is not suitable for bonding wood mainly made of cold pressure, such as furniture and woodworking, which causes trouble when pressed with hot pressure.

  An object of the present invention is to provide an aqueous adhesive composition that exhibits sufficient water-resistant adhesion not only in hot pressure but also in cold pressure.

  Another object of the present invention is to have a stable coating property or adhesive strength by exhibiting a stable viscosity without gelation even when the temperature is changed and left for a long time, and at the time of pressing in the bonding process. An object of the present invention is to provide an aqueous adhesive composition having excellent workability without adhesion to an iron press.

Invention, the acetoacetyl group-containing polyvinyl alcohol, N, and N- diglycidyl amino group-containing compounds, see containing a copolymer emulsion or a copolymer latex, the copolymer emulsion carboxyl-modified emulsions according to claim 1 Alternatively, it is an amino group-containing emulsion, and the aqueous latex composition is characterized in that the copolymer latex is a carboxy-modified latex .

The invention according to claim 2 is the invention according to claim 1 , wherein the carboxy-modified emulsion is a carboxy-modified vinyl acetate- (meth) acrylate copolymer emulsion, a carboxy-modified ethylene-vinyl acetate copolymer emulsion. A water-based adhesive composition.

The invention according to claim 3 is the aqueous adhesive composition according to claim 1 , wherein the amino group-containing emulsion is an amino group-containing (meth) acrylic ester copolymer emulsion.

The invention according to claim 4 is the aqueous adhesive composition according to claim 1 , wherein the carboxy-modified latex is a carboxy-modified diene copolymer latex having a gel content of 20 to 95% by mass. .

The invention according to claim 5 is the aqueous adhesive composition according to claim 4 , wherein the carboxy-modified diene copolymer latex is a carboxyl-modified styrene-butadiene copolymer latex.

According to the aqueous adhesive composition of the present invention, by containing an acetoacetyl group-containing polyvinyl alcohol, an N, N-diglycidylamino group-containing compound, and a predetermined copolymer emulsion or copolymer latex, Since sufficient water-resistant adhesiveness is expressed only by pressure, it can be suitably used not only for bonding wood mainly composed of hot pressure such as plywood but also for bonding wood mainly composed of cold pressure such as furniture and woodworking. . Moreover, since the stability of the viscosity by a temperature change is excellent, stable coating property and adhesive strength can be obtained.

  The best mode of the present invention will be described below.

The aqueous adhesive composition of the present invention comprises an acetoacetyl group-containing polyvinyl alcohol, an N, N-diglycidylamino group-containing compound, and a predetermined copolymer emulsion or copolymer latex. Thereby, sufficient water-resistant adhesiveness can be expressed with cold pressure. Therefore, the aqueous adhesive composition of the present invention can be suitably used particularly as a cold pressure aqueous adhesive composition.

  Specifically, when a plywood is produced using the aqueous adhesive composition of the present invention, the pressing is performed for about 10 to 60 minutes under the pressing conditions of a temperature of 0 to 40 ° C. and a pressure of 0.5 to 1.5 MPa. A plywood that can withstand practical use can be produced. In terms of viscosity stability, a stable viscosity can be maintained for a long time even in a high temperature environment around 40 ° C.

  The technical reason why the water-based adhesive composition of the present invention exhibits sufficient water-resistant adhesion at a cold pressure of 0 to 40 ° C. is not always clear, but is probably an N, N-diglycidylamino group-containing compound. , Acetacetyl-containing polyvinyl alcohol, which is one of the essential components, contributes to the promotion of the curing reaction with respect to the curing reaction at room temperature that is considered to occur between the copolymer emulsion or the copolymer latex. This is presumably due to a strong synergistic effect. In addition, since the water-based adhesive composition of the present invention exhibits excellent water-resistant adhesion even when pressed with hot pressure, it can also be used as an adhesive for plywood mainly composed of hot pressure.

  The acetoacetyl group-containing polyvinyl alcohol constituting the aqueous adhesive composition of the present invention is a polyvinyl alcohol polymer having an acetoacetyl group in the molecule. This acetoacetyl group-containing polyvinyl alcohol can be obtained, for example, by the following method. That is, the acetoacetyl group-containing polyvinyl alcohol can be obtained by reacting polyvinyl alcohol and diketene by a known method. For example, polyvinyl alcohol is dispersed in an acetic acid solvent, and a diketone is added thereto. In this method, alcohol is previously dissolved in a solvent such as dimethylformamide or dioxane, and diketene is added thereto. Also, a method of obtaining polyvinyl alcohol containing acetoacetyl group by directly contacting diketene gas or liquid diketene with polyvinyl alcohol, or adding an acid catalyst such as sulfuric acid in an organic solvent such as DMF, DMSO or acetate of polyvinyl alcohol to esterify acetoacetate There is also a method of obtaining acetoacetyl group-containing polyvinyl alcohol by exchange.

  The polymerization degree of the acetoacetyl group-containing polyvinyl alcohol used is preferably 200 to 3000. The degree of polymerization affects the viscosity and adhesive strength in the aqueous adhesive composition of the present invention. Use of a polymer having a degree of polymerization less than the lower limit is not preferred because the adhesive strength tends to be insufficient. Moreover, it is not preferable to use a polymer having a degree of polymerization exceeding the upper limit because the adhesive composition tends to increase in viscosity. Among these, those having a polymerization degree of 500 to 2500, more preferably 1000 to 2000 are particularly preferable. The saponification degree of the acetoacetyl group-containing polyvinyl alcohol to be used is preferably 80 to 100 mol%. The degree of saponification affects the water-resistant adhesion in the aqueous adhesive composition of the present invention. Use of a saponification degree less than the lower limit is not preferable because the water-resistant adhesion tends to decrease. In addition, use of a saponification degree exceeding the upper limit is not preferable because the viscosity stability tends to decrease. Among these, those having a saponification degree of 85 to 99 mol% are particularly preferable. The content of the acetoacetyl group is preferably 0.1 to 10 mol%. If the content of the acetoacetyl group in the molecule is in the above range, it is preferable in terms of obtaining good water-resistant adhesion. Use of an acetoacetyl group having a content of less than the lower limit is not preferable because it is difficult to obtain good water-resistant adhesion. Moreover, it is not preferred to use a acetoacetyl group having a content of less than the lower limit because problems are likely to occur in the solubility of the acetoacetyl group-containing polyvinyl alcohol. Among these, the content of the acetoacetyl group is particularly preferably 2 to 10 mol%, more preferably 3 to 8 mol%.

  The general formula of the N, N-diglycidylamino group-containing compound constituting the aqueous adhesive composition of the present invention is represented by the following formula.

上記式（１）のＤは、炭素数１〜１２の直鎖又は分岐アルキレン基、炭素数１〜１２の環式アルキレン基、フェニレン基、アルキル基置換フェニレン基及びハロゲン置換フェニレン基からなる群より選ばれた１種の２価の基を示す。上記式（１）で表されるＮ，Ｎ−ジグリシジルアミノ基含有化合物としては、具体的には、Ｎ，Ｎ，Ｎ’，Ｎ’−テトラグリシジルエチレンジアミン、Ｎ，Ｎ，Ｎ’，Ｎ’−テトラグリシジルヘキサメチレンジアミン、１，３−ビス（Ｎ，Ｎ−ジグリシジルアミノメチル）シクロヘキサン、１−（Ｎ，Ｎ−ジグリシジルアミノメチル）１，５，５−トリメチル−３−（Ｎ，Ｎ−ジグリシジルアミノ）シクロヘキサン、Ｎ，Ｎ，Ｎ’，Ｎ’−テトラグリシジル−１，４−フェニレンジアミン、（Ｎ，Ｎ，Ｎ’，Ｎ’−テトラグリシジル）ジアミノトルエン、Ｎ，Ｎ，Ｎ’，Ｎ’−テトラグリシジル−１，３−キシレンジアミン、そのハロゲン２置換体またはハロゲン４置換体、ビス（Ｎ，Ｎ−ジグリシジルアミノフェノール）スルホン、４’−（Ｎ，Ｎ−ジグリシジルアミノ）ベンゼンスルホン酸の４’−（Ｎ，Ｎ−ジグリシジルアミノ）フェニルエステル、ビス（Ｎ，Ｎ−ジグリシジルアミノトリメチレン）アルキレングリコール等を挙げることができるが、Ｎ，Ｎ，Ｎ’，Ｎ’−テトラグリシジル−１，３−キシレンジアミン、１，３−ビス（Ｎ，Ｎ−ジグリシジルアミノメチル）シクロヘキサン等が挙げられる。このうち、特に好ましいのは、Ｎ，Ｎ，Ｎ’，Ｎ’−テトラグリシジル−１，３−キシレンジアミン、１，３−ビス（Ｎ，Ｎ−ジグリシジルアミノメチル）シクロヘキサンである。

D in the above formula (1) is a group consisting of a linear or branched alkylene group having 1 to 12 carbon atoms, a cyclic alkylene group having 1 to 12 carbon atoms, a phenylene group, an alkyl group-substituted phenylene group, and a halogen-substituted phenylene group. One selected divalent group is shown. Specific examples of the N, N-diglycidylamino group-containing compound represented by the above formula (1) include N, N, N ′, N′-tetraglycidylethylenediamine, N, N, N ′, N ′. -Tetraglycidylhexamethylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, 1- (N, N-diglycidylaminomethyl) 1,5,5-trimethyl-3- (N, N -Diglycidylamino) cyclohexane, N, N, N ', N'-tetraglycidyl-1,4-phenylenediamine, (N, N, N', N'-tetraglycidyl) diaminotoluene, N, N, N ' , N′-tetraglycidyl-1,3-xylenediamine, its halogen disubstituted or halogen tetrasubstituted, bis (N, N-diglycidylaminophenol) sulfone, 4 ′-(N, N-dig) Cisylamino) benzenesulfonic acid 4 ′-(N, N-diglycidylamino) phenyl ester, bis (N, N-diglycidylaminotrimethylene) alkylene glycol, and the like can be mentioned, but N, N, N ′, N'-tetraglycidyl-1,3-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane and the like can be mentioned. Of these, N, N, N ′, N′-tetraglycidyl-1,3-xylenediamine and 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane are particularly preferable.

Copolymer emulsion constituting the aqueous adhesive composition of the present invention is a carboxy-modified emulsion or an amino group-containing emulsion. The copolymer latex is a carboxy-modified latex.

  The copolymer emulsion or copolymer latex constituting the aqueous adhesive composition of the present invention is, in particular, a copolymer emulsion or copolymer latex of a known polymer and an unsaturated monomer having a carboxyl group. Alternatively, a copolymer emulsion containing an amino group obtained by further modifying the copolymer emulsion of a polymer and an unsaturated monomer containing a carboxyl group with an imino compound. Known polymers include vinyl acetate, vinyl propionate, ethylene, vinyl chloride, vinylidene chloride, vinyl bromide, vinylidene bromide, ethyl vinyl ether, butyl vinyl ether, styrene, styrene derivatives, butadiene, acrylonitrile, chloroprene, 1,3. -The polymer which consists of 1 type, or 2 or more types of unsaturated monomers chosen from the group which consists of hexadiene, isoprene, isobutene, acrylic acid ester, and methacrylic acid ester is mentioned. Examples of unsaturated monomers having a carboxyl group include maleic acid, maleic acid monoester, maleic acid diester, itaconic acid, itaconic acid monoester, fumaric acid, fumaric acid monoester, citraconic acid, citraconic acid monoester, and mesacone. 1 type, or 2 or more types of unsaturated monomers selected from ethylenically unsaturated dicarboxylic acids or esters thereof such as acids and mesaconic acid monoesters and monocarboxylic acids such as crotonic acid, acrylic acid and methacrylic acid Can be mentioned. The amino group-containing emulsion is an amino group-containing (meth) acrylic acid ester copolymer emulsion having an active hydrogen, and the carboxyl group-containing (meth) acrylic acid ester copolymer emulsion is modified with alkyleneimine. Can be obtained. The aqueous adhesive composition of the present invention contains these copolymer emulsions or copolymer latexes, so that it has high adhesion due to a curing reaction that is considered to occur with the N, N-diglycidylamino group-containing compound. Strength is obtained.

  When the above carboxy-modified emulsion or amino group-containing emulsion is used, it is excellent in versatility and most advantageous in terms of cost. Therefore, a carboxy-modified vinyl acetate- (meth) acrylate copolymer emulsion, carboxy-modified emulsion An ethylene-vinyl acetate copolymer emulsion or an amino group-containing (meth) acrylic ester copolymer emulsion is preferred.

  When a carboxy-modified latex is used, a carboxy-modified diene copolymer latex having a gel content of 20 to 95% by mass is preferred. The carboxy-modified latex is preferably a carboxy-modified diene copolymer latex because it is suitable for obtaining high adhesive strength. The reason why the gel content of the carboxy-modified diene copolymer latex is preferably in the above range is that when the gel content is less than the lower limit, the water-resistant adhesive property of the aqueous adhesive composition tends to decrease, and the upper limit. This is because the room temperature film-forming ability of the carboxy-modified diene copolymer latex is extremely lowered, and the resulting adhesive strength is likely to be insufficient. Among these, the gel content is particularly preferably 30 to 85% by mass. As the carboxy-modified diene copolymer latex, a carboxyl-modified styrene-butadiene copolymer latex is particularly preferable because of its excellent versatility and the most advantageous cost.

  The carboxyl group-modified amount of the carboxy-modified emulsion or carboxy-modified latex is preferably 0.5 to 10% by mass. If the carboxyl group modification amount exceeds the upper limit value, it is not preferable because the adhesive composition tends to increase in viscosity, and if it is less than the lower limit value, it is not preferable because sufficient water-resistant adhesiveness is difficult to obtain. Among these, the carboxyl group modification amount is particularly preferably 1.0 to 8% by mass.

  The aqueous adhesive composition of the present invention includes, in addition to the above components, fillers such as heavy calcium carbonate and talc, organic extenders such as wheat flour and corn starch, etc., other dispersants, thickeners, and emulsifiers. Alternatively, a wet defoaming agent or the like can be added as appropriate alone or in combination of two or more thereof.

  Preparation of the aqueous adhesive composition of the present invention comprises an aqueous solution in which acetoacetyl group-containing polyvinyl alcohol is dissolved, a copolymer emulsion or copolymer latex resin, an N, N-diglycidylamino group-containing compound, In addition, it is performed by mixing a filler, a dispersant and the like.

  The addition amount of the acetoacetyl group-containing polyvinyl alcohol aqueous solution is 5 to 200 parts by mass of the resin component contained in the acetoacetyl group-containing polyvinyl alcohol aqueous solution with respect to 100 parts by mass of the resin component in the carboxy-modified emulsion or carboxy-modified latex. Amount. If it is less than the lower limit value, the viscosity of the adhesive composition is extremely lowered, and thus poor coating such as chipping is not preferable. If the upper limit value is exceeded, the viscosity of the adhesive composition is extremely increased and sufficient. Since it is difficult to obtain adhesiveness, it is not preferable. The addition amount of the N, N-diglycidylamino group-containing compound is 1 to 100 parts by mass with respect to 100 parts by mass of the resin component in the carboxy-modified emulsion or carboxy-modified latex. If it is less than the lower limit, it is not preferable because the adhesive effect is insufficient and it is difficult to obtain good water-resistant adhesion, and if it exceeds the upper limit, the viscosity of the adhesive composition is extremely increased, thereby reducing the coating workability. In addition, it is not preferable because poor adhesion strength is likely to occur and the cost increases.

  Next, examples of the present invention will be described together with comparative examples.

<Example 1>
40 mass parts of an aqueous solution containing 15 mass% of acetoacetyl group-containing polyvinyl alcohol (polymerization degree 1500, saponification degree 99 mol%, acetoacetyl group content 5 mol%, carboxyl group content 0 mol%), and the solid content concentration is 55 parts by mass of carboxy-modified vinyl acetate-acrylic acid ester copolymer emulsion (manufactured by High Pressure Gas Industry Co., Ltd.) and 20 parts by mass of heavy calcium carbonate (manufactured by Maruo Calcium Co., Ltd., trade name: Super SS) To obtain a water acid composition. N, N, N ′, N′-tetraglycidyl-1,3xylenediamine (trade name: TETRAD-X, manufactured by Mitsubishi Gas Chemical Co., Inc.) 10 with respect to 100 parts by mass of the resin content contained in the aqueous dispersion composition Mass parts were mixed to prepare an adhesive composition. The adhesive composition did not show any increase in viscosity or gelation when allowed to stand at room temperature (20 ° C.) for at least 10 hours, and had good standing stability.

  The polymerization degree, saponification degree, and acetoacetyl group content of the acetoacetyl group-containing polyvinyl alcohol used in the preparation of the adhesive composition are shown in Table 1 below.

Next, two veneers each having a thickness of 1.8 mm for capol veneer and 12.0 mm for lauan plywood were prepared, and the adhesive composition prepared above was applied on one side of the lauan plywood at a coating amount of 200 g / m ² . It was applied with. After laminating these single plates and pressing them for 30 minutes under a cold pressure condition of a temperature of 20 ° C. and a pressure of 1.2 MPa, four square pieces each having a side of 75 mm were prepared as test pieces.

<Example 2>
Example 1 except that a carboxy-modified ethylene-vinyl acetate copolymer emulsion (Sumitomo Chemical Co., Ltd., trade name: Sumikaflex SF-456HQ) was used instead of the carboxy-modified vinyl acetate-acrylic ester copolymer emulsion. In the same manner as above, an adhesive composition was prepared to obtain a test piece. The adhesive composition did not show any increase in viscosity or gelation when allowed to stand at room temperature (20 ° C.) for at least 10 hours, and had good standing stability.

<Example 3>
Instead of the carboxy-modified vinyl acetate-acrylate copolymer emulsion, a carboxy-modified styrene-butadiene copolymer latex having a solid content of 50% by mass and a gel content of 87% by mass (trade name: DL-, manufactured by Asahi Kasei Chemicals Corporation) Except that 620) was used, an adhesive composition was prepared in the same manner as in Example 1 to obtain a test piece. The adhesive composition did not show any increase in viscosity or gelation when allowed to stand at room temperature (20 ° C.) for at least 10 hours, and had good standing stability.

<Example 4>
Example 1 except that an amino group-containing acrylic emulsion (trade name: KK-94 manufactured by Kuraray Co., Ltd.) having a solid content concentration of 50% by mass was used instead of the carboxy-modified vinyl acetate-acrylate copolymer emulsion. In the same manner as above, an adhesive composition was prepared to obtain a test piece. The adhesive composition did not show any increase in viscosity or gelation when allowed to stand at room temperature (20 ° C.) for at least 10 hours, and had good standing stability.

<Example 5>
Instead of N, N, N ′, N′-tetraglycidyl-1,3xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane (manufactured by Mitsubishi Gas Chemical Company, Inc., trade name: TETRAD-) An adhesive composition was prepared in the same manner as in Example 1 except that C) was used, and a test piece was obtained. The adhesive composition did not show any increase in viscosity or gelation when allowed to stand at room temperature (20 ° C.) for at least 10 hours, and had good standing stability.

<Comparative Example 1>
Instead of an aqueous solution containing 15% by mass of acetoacetyl group-containing polyvinyl alcohol, a carboxy-modified polyvinyl alcohol polymer (polymerization degree 1700, saponification degree 98 mol%, acetoacetyl group content 0 mol%, carboxyl group content 5.5 Except that an aqueous solution containing 15% by mass) was used, an adhesive composition was prepared in the same manner as in Example 1 to obtain a test piece.

<Comparative example 2>
The adhesive composition was the same as in Example 2 except that the aqueous solution containing the carboxy-modified polyvinyl alcohol polymer used in Comparative Example 1 was used instead of the aqueous solution containing 15% by mass of the acetoacetyl group-containing polyvinyl alcohol. An article was prepared to obtain a test piece.

<Comparative Example 3>
The adhesive composition was the same as in Example 3 except that the aqueous solution containing the carboxy-modified polyvinyl alcohol polymer used in Comparative Example 1 was used instead of the aqueous solution containing 15% by mass of the acetoacetyl group-containing polyvinyl alcohol. An article was prepared to obtain a test piece.

<Comparative example 4>
The adhesive composition was the same as in Example 4 except that the aqueous solution containing the carboxy-modified polyvinyl alcohol polymer used in Comparative Example 1 was used instead of the aqueous solution containing 15% by mass of the acetoacetyl group-containing polyvinyl alcohol. An article was prepared to obtain a test piece.

＜比較試験及び評価＞
実施例１〜５及び比較例１〜４で作製した各試験片について、ＪＡＳ普通合板規格に規定する煮沸繰返し試験（Ｉ類浸漬剥離試験）により、それぞれ接着性能を調べた。この煮沸繰返し試験では、試験片を沸騰水中に４時間浸潰した後、６０±３℃の温度で２０時間乾燥し、これを沸騰水中に４時間浸潰し、更に６０±３℃で３時間乾燥した後、剥離状態を判定する。その結果を以下の表２に示す。
なお表２において、記号Ａは、試験片の同一接着層の剥離する部分が全くなかったこと意味する。記号Ｂは、試験片の同一接着層の剥離する部分が、それぞれの側面における長さの１／３未満であったことを意味する。また記号Ｃは、試験片の同一接着層の剥離する部分が、それぞれの側面における長さの１００％（全面）であったことを意味する。

<Comparison test and evaluation>
About each test piece produced in Examples 1-5 and Comparative Examples 1-4, the adhesive performance was investigated by the boiling repeated test (Class I immersion peeling test) prescribed | regulated to JAS normal plywood specification, respectively. In this boiling repeated test, the test piece was immersed in boiling water for 4 hours, then dried at a temperature of 60 ± 3 ° C. for 20 hours, then immersed in boiling water for 4 hours, and further dried at 60 ± 3 ° C. for 3 hours. Then, the peeled state is determined. The results are shown in Table 2 below.
In Table 2, symbol A means that there was no part to be peeled off of the same adhesive layer of the test piece. The symbol B means that the part where the same adhesive layer of the test piece peels was less than 1/3 of the length on each side surface. Moreover, the symbol C means that the part where the same adhesive layer of the test piece peeled was 100% of the length of each side surface (entire surface).

表２から明らかなように、実施例１〜５と比較例１〜４を比較すると、実施例１〜５の合板は、いずれも試験片の同一接着層の剥離する部分が全く発生しない、或いは発生してもごく僅かであり、合格基準である、試験片の同一接着層の剥離する部分が、それぞれの側面における長さの１／３未満であることを満たす優れた接着性を示した。これに対し、比較例１〜４では試験片の同一接着層が全て剥離或いは殆ど剥離してしまい合格基準を満たさなかった。このことから、本発明の水性接着剤組成物が効果的であることが確認された。

As is clear from Table 2, when Examples 1 to 5 and Comparative Examples 1 to 4 are compared, the plywoods of Examples 1 to 5 do not generate any part of the same adhesive layer of the test piece that peels off, or Even if it generate | occur | produced, the outstanding adhesiveness which satisfy | fills that the part which peels of the same contact bonding layer of a test piece which is a very small and is a pass criterion is less than 1/3 of the length in each side surface was shown. On the other hand, in Comparative Examples 1-4, all the same adhesive layers of the test pieces were peeled off or almost peeled off and did not satisfy the acceptance criteria. From this, it was confirmed that the aqueous adhesive composition of the present invention is effective.

  The water-based adhesive composition of the present invention exhibits a sufficient water-resistant adhesive property at a cold pressure and has a stable coating property or adhesive strength by exhibiting a stable viscosity due to a temperature change. It can be used as an adhesive for wood mainly composed of cold pressure such as furniture and woodworking, as well as adhesion of wood mainly composed of pressure.

Claims (5)

And acetoacetyl group-containing polyvinyl alcohol, N, and N- diglycidyl amino group-containing compound, and a copolymer emulsion or copolymer latex seen including,
The copolymer emulsion is a carboxy-modified emulsion or an amino group-containing emulsion,
The aqueous adhesive composition, wherein the copolymer latex is a carboxy-modified latex . Carboxy-modified emulsion vinyl carboxy modified acetate - (meth) acrylic acid ester copolymer emulsion, carboxyl-modified ethylene - vinyl acetate copolymer emulsion in which claim 1 aqueous adhesive composition. Amino group-containing emulsion amino group-containing (meth) aqueous adhesive composition according to claim 1, wherein the acrylic acid ester copolymer emulsion. Carboxy-modified latex aqueous adhesive composition according to claim 1, wherein the carboxy-modified diene copolymer latex having a gel content of 20 to 95 wt%. The aqueous adhesive composition according to claim 4, wherein the carboxy-modified diene copolymer latex is a carboxyl-modified styrene-butadiene copolymer latex.