JP2002285117A - Two-component quick-curable aqueous adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a two-component quick-curable aqueous adhesive having an excellent initial adhesive force, a permanent adhesive force, excellent hot water-resistance and slight uniformity of the adhesive force. SOLUTION: This two-component quick-curable aqueous adhesive comprises an aqueous liquid (A) containing an acetoacetic acid ester group-containing polyvinyl alcohol having 0.3-0.6 block character [η] and an aqueous liquid (B) containing at least one kind of a compound selected from the group consisting of a hydrazine compound, an aldehyde compound, a polyethyleneimine, a polyamide resin and a silane compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an acetoacetic ester group-containing polyvinyl alcohol-based resin (hereinafter referred to as AA
More specifically, the present invention relates to a two-pack type fast-curing aqueous adhesive having excellent adhesiveness, and particularly having a small variation in adhesive strength.

[0002]

2. Description of the Related Art Conventionally, an adhesive called "honeymoon adhesive" has been known as an adhesive for wood materials and the like. Such an adhesive applies a main agent to the adherend surface of one adherend, applies a curing agent to the adherend surface of the other adherend, and presses these surfaces together for a fixed time. Thereby, the main agent and the curing agent react instantaneously on the adherend surface to adhere the adherends to each other, and have a characteristic that the adherends can be instantly adhered to each other.

In recent years, in the wood industry, etc., there has been an attempt to continuously mass-produce a production process using a conveyor system. In such a production process, the bonding speed greatly affects productivity.
There is a demand for an adhesive having a high bonding speed.

For the purpose of improving the bonding speed, Japanese Patent Application Laid-Open No. 6-172727 discloses an average degree of polymerization of 1500 to 1500.
2000, a two-component, separate-coating, fast-setting, water-based adhesive consisting of an aqueous solution of acetoacetylated polyvinyl alcohol and an aqueous solution of a hydrazine compound having a saponification degree of 85 to 90 mol% and an acetoacetyl group content of 5 to 15 mol%. In addition, Japanese Patent Publication No. 1-60192 also discloses a two-liquid separate coating type instant-curing aqueous adhesive comprising an aqueous liquid and / or an aqueous emulsion having an acetoacetyl group and a hydrazine compound. I have.

[0005]

However, when the present inventors examined the above-mentioned adhesives in detail, all the adhesives used general AA-PVA, and although the curing speed was high, the adhesive strength was low. It has been found that variations may occur.

That is, when AA-PVA is used as the main agent, a synthetic resin emulsion is usually used in combination to impart flexibility, toughness, elasticity, and the like to the adhesive layer (Japanese Patent Publication No. 1-60192-11). (See columns 23-26) (in all of the above-mentioned examples of the known literature, a vinyl acetate resin emulsion is used in combination). In such a case, AA-PVA and microemulsion of the emulsion are used. It is speculated that there may be variations in the adhesive strength due to typical compatibility and dispersibility.
In particular, the advantage of the production line as described above is that a uniform (homogeneous) product without variation can be efficiently manufactured. If the variation in adhesive strength is large, the rate of defective products increases, and the productivity is improved. It becomes a factor that hinders. Therefore, to suppress this variation as much as possible,
It is very useful.

[0007]

Accordingly, the present inventor has conducted intensive studies in view of the present situation. As a result, the aqueous liquid (A) containing AA-PVA having a block character [η] of 0.3 to 0.6 has been developed. And a two-component fast-curing aqueous adhesive comprising an aqueous liquid (B) containing at least one compound selected from the group consisting of hydrazine compounds, aldehyde compounds, polyethylene imines, polyamide resins, and silane compounds, meets the above object. This led to the completion of the present invention.

[0008] The block character [η] referred to here is measured by ¹³ C-NMR (as an internal standard substance).
3- (Trimethylsilyl) propionic-2,2,3,3, -d ₄ acid, sodium
salt, the absorption based on the methylene carbon moiety found in the range of 40 to 49 ppm [(OH, OH) = 4
6-49 ppm absorption, (OH, OR) = 43.5-4
5.5 ppm absorption, (OR, OR) = 40-43 pp
m, where OR represents an O-acetate group or an O-acetoacetate group], and more specifically, a value calculated from the following formula (1).

[Η] = (OH, OR) / 2 (OH) (OR) (1) [However, (OH, OR), (OH), and (OR) are all expressed in mole fractions. Calculate)

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

As described above, the AA-PVA used in the aqueous liquid (A) of the two-part quick-curing aqueous adhesive of the present invention has a block character [η] of 0.3 to 0.6 (more preferably, 0.3 to 0.6). 3 to 0.55, especially 0.3 to 0.5), and it is difficult to industrially obtain an acetoacetic acid group-containing PVA having a block character of less than 0.3,
Conversely, if it exceeds 0.6, it becomes difficult to obtain the effects of the present invention.

Conventionally, in controlling the block character value of unmodified PVA, the blocking property is lowered by acid saponification or the alkali saponification (in the presence of a solvent having a low dielectric constant) to reduce the blocking property. However, in order to obtain an AA-PVA having a specific block character value as described above used in the present invention, some contrivance is required during the production of a general AA-PVA.

That is, during the saponification reaction, it is necessary to leave the acetic acid group in a state of high blocking property and then to perform acetoacetic esterification. As a means for increasing the blocking property, a solvent having a low dielectric constant ( A method in which methyl acetate, hexane, benzene, ethyl acetate, liquid paraffin, toluene, acetone, isopropyl acetate, trichloroethylene, xylene, etc. are contained in an amount of 3 to 40% by weight (further 5 to 20% by weight, particularly 10 to 20% by weight). A method of increasing the saponification temperature to 40 to 50 ° C., a method of increasing the resin content at the time of saponification, a method of eliminating moisture in the saponification reaction system, and the like, which can be realized by appropriately combining these methods. .

Hereinafter, the AA-modified PV specifically used in the present invention will be described.
The method for producing A will be described. AA used in the present invention
The PVA is obtained by reacting PVA with diketene or reacting PVA with acetoacetate to transesterify as described below to introduce an acetoacetate group into PVA. Generally, a saponified product or a derivative thereof obtained by saponifying a lower alcohol solution of polyvinyl acetate with a saponification catalyst such as an alkali or an acid is used, and further a monomer having copolymerizability with vinyl acetate and vinyl acetate are used. And the like can also be used.

Examples of the monomer include ethylene, propylene, isobutylene, α-octene, α-dodecene,
Olefins such as α-octadecene, acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride,
Unsaturated acids such as itaconic acid or salts thereof or mono- or dialkyl esters; nitriles such as acrylonitrile and methacrylonitrile; amides such as acrylamide and methacrylamide; olefins such as ethylenesulfonic acid, allylsulfonic acid and methallylsulfonic acid Sulfonic acids or salts thereof, alkyl vinyl ethers,
N-acrylamidomethyltrimethylammonium chloride, allyltrimethylammonium chloride, dimethyldiallylammonium chloride, dimethylallylvinylketone, N-vinylpyrrolidone, vinyl chloride, vinylidene chloride, polyoxyethylene (meth) allyl ether, polyoxypropylene (meth) allyl Polyoxyalkylene (meth) allyl ether such as ether, polyoxyethylene (meth) acrylate, polyoxyalkylene (meth) acrylate such as polyoxypropylene (meth) acrylate, polyoxyethylene (meth)
Polyoxyalkylene (meth) acrylamide such as acrylamide, polyoxypropylene (meth) acrylamide, polyoxyethylene (1- (meth) acrylamide-1,1-dimethylpropyl) ester, polyoxyethylene vinyl ether, polyoxypropylene vinyl ether, poly Oxyethylene allylamine, polyoxypropylene allylamine, polyoxyethylene vinylamine, polyoxypropylene vinylamine and the like can be mentioned.

As the PVA used as the raw material of the AA-PVA, the above-mentioned saponified product can be used. However, when producing such a saponified product, some contrivance is required as described above. That is, it is necessary that the degree of saponification of the obtained PVA be 98 mol% or less (more preferably 80 to 97 mol%, particularly 85 to 95 mol%). When the saponification degree is 98 mol% or more, [η ] = P of 0.3-0.6
It becomes difficult to obtain VA. Although the lower limit of the saponification degree is not specified, if it is too low, the water solubility of PVA is reduced, and it may be difficult to prepare an aqueous liquid.

The average degree of polymerization of the obtained PVA is 30.
0 to 4000 (further 500 to 3500, especially 700 to
3000), and the degree of polymerization is 30.
If it is less than 0, it is difficult to obtain a sufficient adhesive strength. On the other hand, if it exceeds 4000, the viscosity of the adhesive becomes too high, which causes not only a problem in workability but also a decrease in "wetability" to an adherend. As a result, the adhesive strength is undesirably reduced.

Further, the shape of the PVA is not particularly limited. However, in consideration of uniform adsorption of diketene, uniform reaction by absorption, and improvement of the reaction rate with diketene, which will be described later, the shape of the powder, especially the particle size distribution, is considered. Is preferably narrow and porous, and the particle size is preferably from 50 to 450 mesh, and more preferably from 80 to 320 mesh.

Further, the PVA may contain several weight% of alcohols and water during the production process, and these components react with diketene to consume diketene and reduce the reaction rate of diketene. So, when submitting to the reaction,
It is desirable to reduce the temperature as much as possible by performing heating and decompression operations before use.

In the present invention, powdered PVA can be used as the raw material PVA as described above. However, in view of simplification of the manufacturing process, the PVA after the saponification process during the manufacturing of the raw material PVA is considered. Solvents (methanol, methanol, (iso)
It is preferable that the slurry-like PVA containing propanol or the like is substituted with a fatty acid ester and used as a raw material PVA.

In introducing an acetoacetate group into the PVA obtained as described above, a method of reacting PVA with diketene, a method of transesterifying PVA with acetoacetate, or a method of converting vinyl acetate and vinyl acetoacetate. Although a method of copolymerization and the like can be mentioned, it is preferable to produce by a method of reacting PVA (powder) with diketene from the viewpoint that the production process is simple and a high quality AA-PVA is obtained.

Hereinafter, such a method will be described, but the method is not limited thereto. As a method of reacting PVA powder and diketene, PVA may be directly reacted with gaseous or liquid diketene, or an organic acid may be reacted with PVA.
A method of spraying and reacting liquid or gaseous diketene under an inert gas atmosphere after pre-adsorbing and absorbing the powder, or spraying and reacting a mixture of an organic acid and liquid diketene on PVA powder is used. .

In the method using an organic acid, acetic acid is most advantageous as the organic acid, but is not limited thereto, and propionic acid, butyric acid, isobutyric acid and the like can be optionally used. The amount of the organic acid is preferably within the limit that the PVA powder in the reaction system can adsorb and occlude, in other words, the amount of the organic acid separated from the resin in the reaction system does not exist. Specifically, 0.1 to 80 parts by weight, preferably 0.5 to 50 parts by weight, particularly preferably 5 to 30 parts by weight of an organic acid is suitably co-present with 100 parts by weight of PVA.
Outside this range, the degree of acetoacetic esterification (hereinafter referred to as A
(It may be abbreviated as the degree of A conversion.) A product having a non-uniform distribution is likely to be obtained, unreacted diketene tends to increase, and a gel or the like may be generated, which is not preferable.

In order to uniformly adsorb and occlude the organic acid on the PVA, any means such as a method of spraying the organic acid alone onto the PVA, a method of dissolving the organic acid in an appropriate solvent and spraying the same can be used. is there. As for the reaction conditions of PVA and diketene, when liquid diketene is uniformly adsorbed and absorbed by means such as spraying on PVA powder, it is heated to a temperature of 20 to 120 ° C. in an inert gas atmosphere and stirred for a predetermined time. Alternatively, it is preferable to continue fluidization.

When the diketene gas is reacted, the contact temperature is from 0 to 250 ° C., preferably from 25 to 100 ° C., and the gaseous diketene is contacted at a temperature at which it does not liquefy when it comes into contact with PVA and under a diketene partial pressure condition. Although it is preferable that some of the gas is turned into droplets, there is no problem. The contact time depends on the contact temperature, that is, when the temperature is low, the time is long, and when the temperature is high, the time may be short. The contact time is appropriately selected from the range of 1 minute to 6 hours.

When the diketene gas is supplied, the diketene gas may be used as it is, or a mixed gas of the diketene gas and an inert gas may be used. However, it is preferable to bring the gas into contact after heating.

As a catalyst for the reaction of acetoacetic esterification (hereinafter sometimes abbreviated as AA), basic compounds such as sodium acetate, potassium acetate, primary amine, secondary amine and tertiary amine are effective. The amount of the catalyst may be smaller than that of a known reaction method, and may be less than 0.1% based on the PVA powder.
1 to 1.0% by weight. Since PVA powder usually contains sodium acetate, it is often unnecessary to add a catalyst. If the amount of the catalyst is too large, a side reaction of diketene easily occurs, which is not preferable.

As a reaction device for carrying out AA conversion,
A device that can be heated and has a stirrer is sufficient. Examples thereof include a kneader, a Henschel mixer, a ribbon blender and other various blenders, and a stirring and drying device.

The content of the acetoacetate group in the AA-PVA is preferably 1 to 10 mol% (more preferably 2 to 8 mol%, particularly 3 to 7 mol%), and the content is 1 mol%. %, Adhesive strength is not sufficiently obtained.
If it exceeds 0 mol%, no remarkable improvement in the effect is observed, which is not preferable.

Thus, an AA-PVA used as a main component of the two-pack type fast-curing aqueous adhesive of the present invention is obtained. In the present invention, an aqueous liquid (A) containing the AA-PVA is used as the main component. (Hereinafter, may be referred to as A liquid). That is, such AA-P
The main agent is in the form of an aqueous solution or a dispersion (emulsion) of VA.

In the case of the former aqueous solution, such AA
Can be directly dissolved in water, and the concentration of the aqueous solution at this time is 1 to 30% by weight.
(More preferably 1 to 25% by weight, particularly 1 to 20% by weight). If the concentration is less than 1% by weight, it may be difficult to obtain a sufficient effect.
If the content exceeds 0% by weight, the viscosity of the aqueous solution becomes high, and workability may become difficult, which is not preferable.

In the case of the latter emulsion, AA PV
An emulsion containing A may be prepared. In such preparation, 1) a method in which a monomer is emulsion-polymerized using AA-PVA as an emulsifier or a protective colloid, and 2) a solution or melt of a synthetic resin is mixed with AA-PVA. 3) a method of adding an AA-PVA to a synthetic resin emulsion obtained by an arbitrary method to produce a more stable emulsion, and the like, which will be specifically described. However, the present invention is not limited to these methods.

1) Method by emulsion polymerization Ethically unsaturated monomer and / or diene monomer are added temporarily or continuously in the presence of water, AA-PVA and polymerization catalyst, and heated and stirred. Ordinary emulsion polymerization method such as,
In the presence of water, AA-PVA and a polymerization catalyst, the ethylenically unsaturated monomer and / or diene-based monomer is converted to AA-PVA.
An emulsion polymerization method in which a dispersion (pre-emulsion) mixed and dispersed in an aqueous solution of the above is temporarily or continuously added, followed by heating and stirring can be carried out.

The amount of AA-PVA used varies somewhat depending on the resin content of the emulsion, but the lower limit is usually 0.1% by weight (further 1% by weight, especially 2% by weight, based on the whole emulsion polymerization reaction system). %), And the upper limit is 3
It is preferably 0% by weight (more preferably 25% by weight, especially 20% by weight).

When the amount is less than 0.1% by weight, it is difficult to maintain a stable emulsified state of the polymer particles. On the other hand, when the amount exceeds 30% by weight, the viscosity of the emulsion becomes too high and the workability is lowered. Is not preferred.

As the polymerization initiator, potassium persulfate, ammonium persulfate, potassium bromate or the like is used alone or in combination with sodium acid sulfite, and hydrogen peroxide-tartaric acid, hydrogen peroxide-iron salt, Water-soluble redox-based polymerization initiators such as hydrogen oxide-ascorbic acid-iron salt, hydrogen peroxide-longalit, and hydrogen peroxide-longalit-iron salt are used, and azobisisobutyronitrile and benzoyl peroxide are used. An oil-soluble polymerization initiator such as the above can also be used.

The method of adding the polymerization initiator is not particularly limited, and a method of adding the polymerization initiator all at once or a method of adding the polymerization initiator continuously as the polymerization proceeds can be employed. In the above emulsion polymerization, a water-soluble polymer, a nonionic activator and an anionic activator can be used in combination as an emulsion dispersion stabilizer.

Examples of the water-soluble polymer include unmodified PVA, carboxyl group-containing PVA, and PVA other than AA-PVA.
Formal compound, acetal compound, butyral compound,
Examples thereof include PVA such as urethane compound, esterified compound with sulfonic acid and carboxylic acid, and saponified copolymer of vinyl ester and a monomer copolymerizable therewith. Monomers copolymerizable with vinyl esters include ethylene, butylene, isobutylene, α-octene, α-dodecene, and α-
Olefins such as octadecene, unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, and itaconic acid or salts thereof, mono- or dialkyl esters, etc., nitriles such as acrylonitrile and methacrylonitrile, and acrylamide Amides such as diacetone acrylamide and methacrylamide, olefin sulfonic acids or salts thereof such as ethylene sulfonic acid, allyl sulfonic acid and methallyl sulfonic acid, alkyl vinyl ethers, vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinylidene chloride and the like Is mentioned.

Examples of the water-soluble polymers other than PVA include methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxypropyl methyl cellulose, hydroxybutyl methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, aminomethyl hydroxypropyl cellulose, aminoethyl hydroxypropyl cellulose and the like. Cellulose derivatives, starch, tragacanth, pectin, glue, alginic acid or its salts, gelatin, polyvinylpyrrolidone, polyacrylic acid or its salts, polymethacrylic acid or its salts, polyacrylamide, polymethacrylamide, vinyl acetate and maleic acid, anhydride Copolymers with unsaturated acids such as maleic acid, acrylic acid, methacrylic acid, itaconic acid, fumaric acid, crotonic acid, Copolymers of Ren and the unsaturated acid, salts or esters of the copolymer and the copolymer of vinyl ether and the unsaturated acid.

Examples of the nonionic activator include polyoxyethylene-alkyl ether type, polyoxyethylene-alkylphenol type, polyoxyethylene-polyhydric alcohol ester type, ester of polyhydric alcohol and fatty acid, oxyethylene oxy And propylene block polymers.

Examples of the anionic activator include higher alcohol sulfate, higher fatty acid alkali salt, polyoxyethylene alkylphenol ether sulfate, alkylbenzene sulfonate, naphthalene sulfonate formalin condensate, alkyl diphenyl ether sulfonate,
And dialkyl sulfosuccinates and higher alcohol phosphates. Further, a plasticizer such as a phthalic acid ester and a phosphoric acid ester, and a pH adjuster such as sodium carbonate, sodium acetate and sodium phosphate may be used in combination.

2) Method by post-emulsification In producing an emulsion by the post-emulsification method, AA-PVA is dissolved in water, and a solution of ethylenically unsaturated monomer and / or diene monomer in solution is added thereto. The polymer is added dropwise and stirred or the AA-P is added to the polymer in a solution state.
A VA aqueous solution may be dropped and stirred. There is no particular need for heating for emulsification, but if necessary,
What is necessary is just to heat to about 85 degreeC. There is no particular limitation on the substance to be emulsified, epoxy resin, urethane resin, urea-formalin initial condensate, phenol-formaldehyde initial condensate, alkyd resin, ketene dimer, rosin, silicone resin, wax, polypropylene, polyethylene,
Asphalt and the like.

Although the amount of the AA-PVA used varies somewhat depending on the required resin content of the emulsion, it is usually 0.1 to 30% by weight, preferably 1 to 30% by weight, based on the emulsified substance.
-25% by weight. If necessary, a nonionic activator such as a polyoxyethylene-alkyl ether type, a polyoxyethylene-alkylphenol type, a polyhydric alcohol ester type, or a cationic activator such as a higher alkylamine salt is appropriately used together with the resin. You can also. These activators can also be mixed in the emulsified object.

If necessary, a nonionic activator such as a polyoxyethylene-alkyl ether type, a polyoxyethylene-alkylphenol type, a polyhydric alcohol ester type, or a cationic activator such as a higher alkylamine salt may be used. Any of the various surfactants used in the emulsion polymerization described above can be used in combination. These activators can also be mixed in the emulsified object. Further, a pH adjuster such as phthalate, sodium acetate, sodium phosphate and the like can be used in combination.

3) Method by post-addition In this method, AA-PVA is added to a synthetic resin emulsion obtained by an arbitrary method. Examples of the emulsion include a styrene / butadiene emulsion,
Cis-1,4 polyisoprene emulsion, chloroprene emulsion, acrylonitrile / butadiene emulsion, vinylpyridine emulsion, methyl methacrylate / butadiene emulsion, polyurethane emulsion, acrylic ester emulsion, vinyl acetate emulsion, ethylene / vinyl acetate emulsion,
Examples thereof include a vinyl chloride emulsion, a polystyrene emulsion, a polyethylene emulsion, a silicone emulsion, a polybutene emulsion, and a thiochol emulsion.

When adding AA-PVA to the emulsion, when adding the PVA as an aqueous solution, the aqueous solution may be added to the emulsion while stirring it at room temperature, but the PVA powder is added. Sometimes,
Add the powder while stirring the emulsion and add 50-8
Heating to 5 ° C. is preferable because uniform mixing is completed in a short time.

The amount of the AA-PVA used is 1 to 40% by weight (further 2 to 30% by weight) based on the solid content of the emulsion.
The range of the degree is preferable.

Thus, the aqueous liquid (A) containing AA-PVA having a block character [η] of 0.3 to 0.6
Can be appropriately added to the aqueous liquid (A), if necessary, with additives such as a pigment, a dispersant, and an antifoaming agent thickener.

Next, an aqueous liquid (B) (hereinafter, referred to as a curing agent)
(Sometimes referred to as liquid B). The aqueous liquid (B) is an aqueous liquid containing at least one compound selected from the group consisting of a hydrazine compound, a dialdehyde compound, polyethyleneimine, a polyamide resin, and a silane compound.

Examples of the hydrazine compound include hydrazine, hydrazine hydroxide, inorganic salts of hydrazine such as hydrochloric acid, sulfuric acid, nitric acid, sulfurous acid, phosphoric acid, thiocyanic acid and carbonic acid, and organic salts such as formic acid and oxalic acid; Monosubstituted products such as ethyl, propyl, butyl, and allyl, 1,1-dimethyl, 1,1-diethyl, 4-n-
Examples thereof include symmetric disubstitutes such as butyl-metal, and further, as dihydrazine, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide,
Adipic dihydrazide, azelaic dihydrazide,
Sebacic dihydrazide, dodecane diacid dihydrazide,
Maleic acid dihydrazide, fumaric acid dihydrazide, diglycolic acid dihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, dimer acid dihydrazide, etc. Dibasic acid hydrazide, carbohydrazide, 2,
4-dihydrazino-6-methylamino-sym-triazine, poly (meth) acrylic hydrazide and the like can also be mentioned.

The content of the hydrazine compound in the aqueous liquid (B) is 1 to 50% by weight (further 2 to 25% by weight,
In particular, when the content is less than 1% by weight, the effect of the present invention may not be sufficiently obtained. On the other hand, when the content exceeds 30% by weight, it may not be dissolved in water, The effect of the present invention may not be improved in some cases, which is not preferable.

Examples of the aldehyde compound include monoaldehydes such as formaldehyde, acetaldehyde, propionaldehyde, crotonaldehyde, and benzaldehyde; glyoxal, glutaraldehyde, malondialdehyde, terephthalaldehyde, and dialdehyde starch. Glyoxal is preferred. Used for

The content of the aldehyde compound in the aqueous liquid (B) is 1 to 50% by weight (further 2 to 25% by weight,
In particular, when the content is less than 1% by weight, the effect of the present invention may not be sufficiently obtained. On the other hand, when the content exceeds 30% by weight, it may not be dissolved in water, The effect of the present invention may not be improved in some cases, which is not preferable.

As the polyethyleneimine, those having a molecular weight of about 300 to 100,000 represented by the following general formula (2) can be mentioned. Low molecular weight liquids can be used as they are, but high molecular weight ones can be used. It is preferably used as a 1-40% aqueous solution.

[0055]

As the polyamide-based fat, a polyaminoamide resin having two or more amino groups and amide groups in the molecule is used. Such a resin is a dimer acid obtained from a fatty acid obtained from a drying oil, a semi-dry oil, a tall oil and the like. Polyamide resin which is a condensate of polyamine and polyamine or a condensate and modified product of polycarboxylic acid and polyamine and has reactive primary and secondary amino groups in the molecule. Refers to those widely used as The resin is not particularly limited, but has an amine value of 100 to 8
The viscosity at 00 and 30 ° C. is suitably from 0.5 to 700 poise.

The content of the polyamide resin in the aqueous liquid (B) is preferably 1 to 30% by weight (more preferably 2 to 25% by weight, particularly 3 to 20% by weight). If the amount is less than 30% by weight, the function and effect of the present invention may not be sufficiently obtained. On the contrary, if the amount exceeds 30% by weight, the viscosity of the aqueous liquid becomes high, which may cause a problem in workability.

The silane compound is preferably represented by the following general formula (3): Y—R—Si (CH ₃ ) _3-n X _n (3) (where Y is a vinyl group, Epoxy group, amino group, methacryl group, mercapto group, chloro group, X is an alkoxy group,
R is an alkyl group, an alkylene group, and n is 1, 2 or 3
Is shown. ) Specifically, γ-aminopropyltrimethoxysilane,
N-β (aminoethyl) γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ
-Methchlorooxypropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane,
β-epoxycyclohexylethyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane and the like can be mentioned.

The content of the silane compound in the aqueous liquid (B) is preferably 1 to 50% by weight (more preferably 2 to 40% by weight, particularly 3 to 30% by weight). If the amount is less than 1% by weight, the function and effect of the present invention may not be sufficiently obtained. Conversely, if the amount exceeds 50% by weight, no remarkable improvement in the effect can be obtained, which is not preferable.

Thus, a two-pack type fast-setting aqueous adhesive comprising the aqueous liquids (A) and (B) as described above is obtained. The curable aqueous adhesive is usually used by separately applying a liquid A and a liquid B to an adherend.

That is, the solution A is applied to the surface of the substrate to be bonded, such as wood, and the solution B is applied to the surface of the other substrate to be bonded. When both sides are brought into contact with each other and pressed, they adhere to a considerable strength within a few seconds to 10 minutes at room temperature, so that they can be decompressed.

The two-pack type fast-curing aqueous adhesive of the present invention has excellent initial adhesive strength, permanent adhesive strength, excellent heat-resistant water adhesive strength, less variation in adhesive strength, wood and plywood. , Particle board, hard board etc., fibrous material, slate board, siliceous board, mortar, tile etc., inorganic material, melamine decorative board, bakelite, styrofoam etc. plastic material, corrugated cardboard, paperboard,
It is useful for high-speed bonding of paper materials such as kraft paper.

[0063]

The present invention will be described below in more detail with reference to examples. Unless otherwise noted, "%",
“Parts” indicate weight standards.

Example 1 (Production of PVA) Polyvinyl acetate obtained by a conventional method (average degree of polymerization: 2,000; completely saponified to JIS K6)
Methyl acetate was added to a methanol solution of polyvinyl acetate / methanol /
After adjusting so that methyl acetate = 48/39/13 (weight ratio) to obtain a polyvinyl acetate solution, 100 parts of the solution was charged into a kneader, and the solution temperature was adjusted to 40 ° C. When the liquid temperature reached 40 ° C., 3 parts of a 2% aqueous sodium hydroxide solution was charged as a catalyst and saponification was performed for 1.4 hours. Then, after neutralizing with acetic acid to stop the saponification reaction, washing is repeatedly performed with methanol, and then drying is performed to obtain a P having a saponification degree of 88 mol% (residual acetic acid group: 12 mol%).
VA was obtained.

(Production of AA-PVA) The P
200 parts of VA powder was charged into a kneader, and acetic acid 2 was added thereto.
After adding 0 parts and swelling, the temperature was raised to 60 ° C. while stirring at a rotation speed of 20 rpm, 20 parts of diketene was added dropwise over 4 hours, and the mixture was further reacted for 30 minutes to obtain AA-PVA. The degree of acetoacetylation of the obtained AA-PVA was 2.5 mol%, and the block character [η] was 0.48.

In calculating the block character [η], the block character [η] was calculated from the measurement result of ¹³ C-NMR measured under the following conditions. Measurement instrument: Burker Co. "AVANCE DPX400" solvent: D ₂ O integration number: 8192 pulse interval: 2 seconds Internal standard substance: 3- (Trimethylsilyl) propionic-2,2,3,3 , -d 4 acid, sodiumsalt Measurement temperature: 50 ° C Concentration: 7.5%

[Preparation of two-pack type fast-curing aqueous adhesive] The following base agent and curing agent were prepared. -Main agent (Solution A): 100 parts of the above 10% aqueous solution of AA-PVA 100 parts Vinyl acetate resin emulsion with a solid content of 42% 50 parts ("Movinyl AD50" manufactured by Clariant Polymer Co., Ltd.)-Curing agent (Solution B): Adipoyl 10% aqueous solution of hydrazide

The following evaluation was performed using the two-pack type fast-curing aqueous adhesive prepared above. Normal adhesive strength A main agent (solution A) is applied to one of the ^two surfaces of birch material having a size of 25 mm x 30 mm x 10 mm so as to be 100 g / m2, and a curing agent (solution B) is applied to the other surface. was coated to a 50 g / m ^2, immediately 5 kg / cm is adhered to both sides
Press in ² and release after 5 seconds, immediately after 5 minutes and 72
The adhesive strength after time (left at room temperature) was measured in accordance with JIS K 6852. The measurement was performed on 100 samples, and the average value was measured as the adhesive force (kg / c).
m ² ), and the number of samples exhibiting a value lower than 80% of the adhesive force of the average value was examined to determine the variation in the adhesive force.

Water-Resistant Adhesive Strength An adhesive sample prepared as described above was left at room temperature for 72 hours, immersed in boiling water for 4 hours, dried in air at 60 ° C. for 20 hours, and immersed again in boiling water for 4 hours. After that, the adhesive strength immediately after being taken out of the water (while still wet) was measured by JIS K68.
52.

Adhesive strength after standing The two-pack type fast-curing aqueous adhesive prepared above was cured at 30 ° C. for 1 hour.
After standing for a month, the same evaluation as the above (normal adhesive strength) was performed.

Example 2 In Example 1, the two-component quick-curing aqueous adhesive was as follows: Main agent (Solution A): 100 parts of a 10% aqueous solution of the above-mentioned AA-PVA 100 parts Vinyl acetate resin emulsion having a solid content of 42% 50 parts (“Movinyl AD50” manufactured by Clariant Polymer Co., Ltd.) Curing agent (Solution B): A 10% aqueous solution of glyoxal was prepared and evaluated in the same manner.

Example 3 Example 2 was repeated except that a 20% aqueous solution of polyethyleneimine having a degree of polymerization of about 70,000 was prepared and used as a curing agent (solution B) for the two-part quick-curing aqueous adhesive. Evaluation was performed similarly.

Example 4 In Example 2, a 20% aqueous solution of a polyaminoamide resin (“Tomide # 2500” manufactured by Fuji Kasei Kogyo Co., Ltd.) was prepared as a curing agent (liquid B) for a two-pack type fast-curing aqueous adhesive. The evaluation was performed in the same manner except that the above was used.

Example 5 In Example 2, a 20% aqueous solution of N-β (aminoethyl) γ-aminopropyltrimethoxysilane was prepared as a curing agent (solution B) for a two-part quick-curing aqueous adhesive. Except for using, evaluation was performed in the same manner.

Example 6 In Example 1 (Production of PVA), the saponification
The same procedure was carried out except that the time was changed to obtain PVA having a saponification degree of 92.9 mol% (residual acetic acid groups: 7.1 mol%). PV
Production of A was performed to obtain AA-PVA having a degree of acetoacetylation of 4.5 mol%. The block character [η] of the obtained AA-PVA was 0.54. AA obtained
Using the modified PVA, a two-part fast-curing aqueous adhesive was prepared in the same manner as in Example 1, and was similarly evaluated.

Example 7 The procedure of Example 1 (manufacture of PVA) was repeated except that the composition of the polyvinyl acetate solution was changed to polyvinyl acetate / methanol / methyl acetate = 48/44/8 (weight ratio). , Saponification degree 90.1 mol% (residual acetic acid group 9.9 mol%)
Was prepared in the same manner as above except that the amount of the diketene added was changed to 20 parts to obtain an AA-PVA having a degree of acetoacetylation of 2.5 mol%. The block character [η] of the obtained AA-PVA is 0.5
It was 7. Example 1 was prepared using the obtained AA-PVA.
A two-part quick-curing aqueous adhesive was prepared in the same manner as in the above, and evaluated in the same manner.

Example 8 In Example 1 (Production of PVA), the polymerization degree was 1200.
Of polyvinyl acetate having a saponification degree of 88.5 mol% (residual acetic acid groups of 11.5 mol%).
A was obtained, and then the production of AA-PVA was carried out in the same manner except that the dropping amount of diketene was changed to 33 parts to obtain an AA-PVA having a degree of acetoacetylation of 4.5 mol%. AA obtained
The block character [η] of the modified PVA was 0.57. Using the obtained AA-PVA, a two-part quick-curing aqueous adhesive was prepared in the same manner as in Example 1, and the evaluation was performed in the same manner.

Example 9 In Example 1 (manufacture of PVA), the composition of the polyvinyl acetate solution was set to polyvinyl acetate / methanol / methyl acetate = 48/34/18 (weight ratio). The same procedure was carried out except that the charged amount was 3.5 parts, to obtain PVA having a saponification degree of 87.5 mol% (residual acetic acid group: 12.5 mol%), and then the amount of the diketene dropped was 35 parts. Except for the above, an AA-PVA was produced in the same manner to obtain an AA-PVA having an acetoacetylation degree of 4.4 mol%. The block character [η] of the obtained AA-PVA was 0.49. Using the obtained AA-PVA, a two-part fast-curing aqueous adhesive was prepared in the same manner as in Example 1 and evaluated in the same manner.

Example 10 10 parts of the AA-modified PVA obtained in Example 9 was dissolved in a separable flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer by adding 90 parts of water to a temperature of 70 ° C. Further, 0.02 parts of sodium acetate and 10 parts of vinyl acetate monomer were charged as a pH adjuster, and 5 parts of a 1% aqueous solution of ammonium persulfate was added as a polymerization initiator while stirring to start polymerization. One hour after the start of the polymerization, 90 parts of a vinyl acetate monomer was further added dropwise over 4 hours to carry out the polymerization. Meanwhile 1
Every hour, 5 parts of a 1% aqueous solution of ammonium persulfate was added. After aging for 1 hour, the mixture was cooled to obtain a polyvinyl acetate resin emulsion having a solid content of 50%. Evaluation was performed in the same manner as in Example 1 except that 150 parts of this emulsion was used as the main agent (agent A).

Comparative Example 1 Using the polyvinyl acetate of Example 1, a polyvinyl acetate solution of vinyl acetate / methanol = 50/50 (weight ratio) was prepared. 100 parts of the obtained solution was charged into a kneader, the temperature was raised to reflux, 0.8 parts of sulfuric acid was charged, saponification was performed for 12 hours, and the mixture was neutralized with sodium hydroxide. 9 mol% of PVA was obtained. P obtained
VA was converted to AA according to Example 1, and the degree of AA conversion was 2.7 mol%.
VA was obtained. Example 1 was prepared using the obtained AA-PVA.
The evaluation was performed in the same manner as described above.

Comparative Example 2 In Example 2, AA-PVA was used in Comparative Example 1
The same evaluation was performed except that the PVA was changed to PVA.

Comparative Example 3 In Example 3, AA-PVA was used in Comparative Example 1
The same evaluation was performed except that the PVA was changed to PVA.

Comparative Example 4 In Example 4, AA PVA was used in Comparative Example 1
The same evaluation was performed except that the PVA was changed to PVA.

Comparative Example 5 In Example 5, AA-PVA was used in Comparative Example 1
The same evaluation was performed except that the PVA was changed to PVA.
Table 1 shows the evaluation results of the examples and the comparative examples.

[Table 1]     Immediately 5 minutes later 72 hours later Example 1 47 (7 pieces) 113 (3 pieces) 241 (0 pieces) 161 230 (2 pieces) 〃 2 28 (10 pieces) 75 (8 pieces) 192 (0 pieces) 124 175 (3 pieces) ３ 3 30 (11) 72 (8) 185 (0) 126 180 (4) 〃 4 33 (13) 87 (7) 221 (0) 139 210 (2) ５ 5 31 (14) 77 (9 pieces) 175 (0 pieces) 121 165 (5 pieces) ６ 643 (9 pieces) 101 (4 pieces) 229 (0 pieces) 153 227 (2 pieces) ７ 7 39 (11 pieces) 98 (5 pieces) ) 213 (0) 147 208 (3) 〃 8 41 (9) 100 (5) 219 (0) 150 209 (5) ９ 949 (5) 119 (3) 255 (0) ) 163 249 (1)〃 10 51 (4) 121 (2) 255 (0) 181 247 (1) Comparative Example 1 24 (39) 99 (18) 165 (7) 84 128 (15) 〃 2 14 (45) 59 (21) 145 (5) 76 107 (17) ３ 3 15 (32 pieces) 57 (23 pieces) 150 (6 pieces) 78 125 (15 pieces) ４ 416 (39 pieces) 72 (20 pieces) 140 (8 pieces) 72 120 (20 pieces)〃 5 16 (32 pieces) 62 (25 pieces) 135 (11 pieces) 73 115 (22 pieces) Note) indicates normal bonding strength, indicates water-resistant bonding strength, and indicates bonding strength after standing. The number in parentheses indicates the variation-number-.

[0086]

According to the present invention, the two-pack type fast-curing aqueous adhesive has an AA-PV having a specific block character [η] value.
Because A is used, it has excellent initial adhesive strength, permanent adhesive strength, excellent hot water adhesive strength, less variation in adhesive strength, wood, plywood, particle board, hard board, etc. It is useful for high-speed bonding of inorganic materials such as fibrous materials, slate boards, silica plates, mortars, tiles, etc., plastic materials such as melamine decorative boards, bakelite and styrofoam, and paper materials such as corrugated cardboard, paperboard and kraft paper.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09J 179/02 C09J 179/02 183/04 183/04 F term (Reference) 4J040 DD021 EG022 EH012 EK032 GA05 GA07 HB17 HC15 HD30 JA13 KA10 MA01 MA08 MA09 MA10 NA12 4J100 AD02P BA03H BA15H CA01 CA04 CA31 DA01 DA28 HA09 HA13 HC25 HC33 JA03

Claims (3)

[Claims] 1. A block character [η] of 0.3 to
An aqueous liquid (A) containing an acetoacetic ester group-containing polyvinyl alcohol of 0.6 and an aqueous liquid (B) containing at least one compound selected from the group consisting of hydrazine compounds, aldehyde compounds, polyethyleneimines, polyamide resins, and silane compounds ), A two-part fast-curing aqueous adhesive. 2. The two-pack type fast-curing aqueous adhesive according to claim 1, wherein the average degree of polymerization of the acetoacetic ester group-containing polyvinyl alcohol is 300 to 4000. 3. The acetoacetate group-containing polyvinyl alcohol according to claim 1, wherein the content of the acetoacetate group is 1 to 10 mol%.
Liquid-type fast-curing aqueous adhesive.