JPH08225780A - Urethane water-born adhesive composition - Google Patents

Abstract

PURPOSE: To obtain a urethane water-born adhesive composition which is excellent in ordinary joint strength and hydrolysis resistance. CONSTITUTION: (A) A polyisocyanate bearing 2 or more isocyanate groups, (B) a polyol bearing 2 or more hydroxyl groups and having 500-10,000 molecular weight and (C) a dimethylolalkanoic acid are used as essential components and they are allowed to react under such conditions where the isocyanate groups are excessive to the hydroxyl groups to give a urethane prepolymer bearing isocyanate groups on the chain ends. While or after the urethane prepolymer is dispersed in water, a diamine bearing 2 or more of primary and/or secondary amino groups and/or water are added as a chain extender to give this urethane water-born adhesive composition where the polyol (B) comprises 5-100wt.% of a polyester polyol obtained by reaction of dimer acid with an alkylene diol.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a urethane-based water-based adhesive composition having excellent water resistance, heat resistance, and hydrolysis resistance.

[0002]

2. Description of the Related Art Urethane-based water-based adhesives are widely used because they have excellent adhesiveness to a wide range of adherends, have excellent properties such as flexibility, and are suitable for many purposes.
On the other hand, since the organic solvent is volatilized, it is necessary to recover the organic solvent in the workplace and provide equipment such as ventilation, and conversion from a solvent-based adhesive to a water-based adhesive is under study.

In making a urethane-based adhesive water-based,
Generally, when a urethane polymer is water-dispersed using an emulsifier, the emulsifier remains in the dried film and the water resistance of the film is impaired. Therefore, when such a urethane-based water-based adhesive is used, the cohesive force of the adhesive layer is reduced due to water absorption, and the water resistance thereof is significantly reduced.

Therefore, a self-dispersing urethane polymer having an ionic, latent ionic functional group and / or a nonionic hydrophilic group in the molecule is stably dispersed in water without using an emulsifier. Self-dispersing aqueous urethane dispersions are known.

For example, in JP-A-3-21626, a carboxyl group is introduced into a polyurethane chain. In this case, if a volatile basic compound is used as the ionizing agent for the carboxyl group, the ionizing agent scatters during drying, and thus the water resistance of the film is prevented from lowering.

Further, a polyester skeleton as a skeleton of a self-dispersible urethane-based water-based adhesive, particularly one having an adipic acid-based polyester skeleton, has excellent adhesiveness and is therefore widely used. For example, JP-A-63-69
Japanese Patent No. 882 discloses a self-dispersing aqueous adhesive containing a carboxyl group or a sulfonyl group and having an adipic acid polyester skeleton.

[0007]

By the way, since adipic acid type polyesters generally have crystallinity, and the urethane polymer obtained therefrom also shows crystallinity, those having sufficient flexibility and flexibility can be obtained. In addition, the heat resistance was insufficient at the crystal melting point or higher. In addition, the ester bond of adipic acid polyester is susceptible to hydrolysis in the presence of water, and therefore when a water-based adhesive is used, when the joint is exposed to high temperature and humidity for a long time, the polymer There are problems that the chain is broken and the adhesive strength is reduced, and that the molecular weight is lowered by being hydrolyzed by water as a dispersion medium during storage.

The present invention is intended to solve the above-mentioned drawbacks of conventional water-based adhesives, and to provide a urethane-based water-based adhesive having excellent room-temperature adhesive strength, heat-resistant adhesive strength, and hydrolysis resistance.

[0009]

The urethane-based aqueous adhesive composition of the present invention has a polyisocyanate compound (A) having two or more isocyanate groups, two or more hydroxyl groups, and a molecular weight of 500 to 10, Urethane having an isocyanate group at the end, obtained by reacting 000 polyol compound (B) and dimethylolalkanoic acid compound (C) as essential components and reacting them under the condition that the isocyanate group is excessive with respect to the hydroxyl group. During or after dispersion of the prepolymer in water, the primary and / or secondary amino groups are
A urethane-based water-based adhesive composition containing as a main component an aqueous dispersion of a urethane polymer obtained by chain-extending the urethane prepolymer with at least one diamino compound and / or water, the polyol compound (B) Is 5% to 100% by weight of the polyester polyol obtained by the reaction of dimer acid and alkylene diol.

The polyisocyanate compound (A) having two or more isocyanate groups is, for example,
1,4-tetramethylene diisocyanate, 1,6-tetramethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 3-isocyanate methyl-3,5,5-trimethyl Cyclohexyl isocyanate, dicyclohexylmethane-4,4'-
Fatty acids such as diisocyanate, methylcyclohexyl-2,4-diisocyanate, methylcyclohexyl-2,6-diisocyanate, xylene diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, tetramethylxylene diisocyanate, transcyclohexane-1,4-diisocyanate Group isocyanates, 2,4-toluylene diisocyanate, 2,6
-Toluylene diisocyanate, diphenylmethane-
Aromatic diisocyanates such as 4,4′-diisocyanate, 1,5-naphthene diisocyanate, tolidine diisocyanate, tetraalkyldiphenylmethane diisocyanate and paraphenylene diisocyanate, lysine diisocyanate, lysine ester triisocyanate, triphenylmethane triisocyanate, 1,6,6.
11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanate methyl octane, 1,
Examples of triisocyanates such as 3,6-hexanemethylenetriisocyanate group and bicycloheptane triisocyanate may be used alone or in admixture of two or more.

It has two or more hydroxyl groups and a molecular weight of 500 to
It is necessary that 10,000 to 100% by weight of the polyol compound (B) of 10,000 be a polyester polyol obtained by the reaction of a dimer acid and an alkylene diol.

The polyester polyol (B) is obtained by reacting a dicarboxylic acid with an alkylene diol, and the dicarboxylic acid component is a dimer component which is a dimer component obtained by polymerizing an unsaturated fatty acid as a main component. An acid hydrogenated product is used. The hydrogenated product of this dimer acid is represented by the following formula (1) or (2).

[0013]

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[0014]

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In the above formula (1), R¹And R²Are both
Is an alkyl group and R¹And R ²Each charcoal contained in
The sum of prime numbers and m and n is 28, and
(2) Medium, R³And R^FourAre all alkyl groups,
And R³And R^FourThe number of carbon atoms contained in q and r
And the total is 32.

In addition to the above-mentioned dimer acid as the dicarboxylic acid component, various dicarboxylic acid compounds can be used as long as they do not impair the object of the present invention to improve hydrolysis resistance and adhesiveness. These dicarboxylic acid compounds include adipic acid, sebacic acid, itaconic acid,
Examples thereof include maleic acid, maleic anhydride, terephthalic acid, isophthalic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, speric acid and azelaic acid.

As the alkylene diol, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol and 3-methyl are used. Examples include -1,5-pentanediol, 1,9-nonanediol, tripropylene glycol and neopentyl glycol.

The above-mentioned polyol compound (B) has a molecular weight of 5
It is preferably from 00 to 10,000, more preferably from 800 to 7,000, particularly preferably from 1,000 to
It is 5,000. If the molecular weight is less than 500, the adhesive obtained will be too hard, and if it is 10,000 or more, the viscosity of the prepolymer before water dispersion will be too high and the dispersion operation will be difficult.

The proportion of the dimer acid-containing polyester polyol in the polyol compound (B) is 5 to 1
Must be 00% by weight. Preferably 15-10
0% by weight. This is because if it is less than 5% by weight, the effect of improving heat-resistant adhesiveness, hydrolysis resistance and the like which is the object of the present invention cannot be obtained. By appropriately selecting the polyols according to the purpose and application, necessary physical properties such as hardness and adhesiveness of the adhesive can be arbitrarily designed.

In the present invention, in addition to the above polyol compound (B), a molecular weight of 500 to 10,0 may be added if necessary.
00 polyols can be used. Examples of the polyols include polyether polyols such as polyethylene glycol and polypropylene glycol,
Adipic acid, sebacic acid, itaconic acid, maleic acid, maleic anhydride, maleic anhydride, terephthalic acid, isophthalic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, speric acid, azelaic acid, etc. Dicarboxylic acid component of ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 3-methyl-
1,5-pentanediol, 1,9-nonanediol,
Tripropylene glycol, polyester polyols obtained from alkylene diol components such as neopentyl glycol, polycaprolactone polyols, polytetramethylene ether polyols, polybutadiene polyols, polyacrylic acid ester polyols and the like,
One or more of them are used.

Examples of the dimethylolalkanoic acid compound (C) include compounds represented by the following formula (3). Specifically, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, 2 , 2-dimethylol valeric acid and the like.

[0022]

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In the formula, R ⁵ represents an alkyl group having 1 to 4 carbon atoms.

The amount of the dimethylolalkanoic acid compound (C) used is 0.1% per 1 g of the urethane prepolymer obtained.
The amount is preferably 1 to 2.0 mmol, more preferably 0.1 to 1.0 mmol.
If it is less than 0.1 mmol, the hydrophilicity of the prepolymer is insufficient, and it is difficult to stably disperse it in water. On the other hand, if it exceeds 2.0 millimoles, the hydrophilicity of the prepolymer becomes too large, so that the water resistance of the water-based adhesive obtained thereafter decreases.

In the present invention, if necessary,
A low molecular weight diol compound having a molecular weight of less than 500 can also be used. Examples thereof include ethylene glycol, 1,4-butanediol, 1,6-hexanediol and the like.

In the present invention, the above compound (A),
A urethane prepolymer having an isocyanate group at the terminal is synthesized by reacting (B) and (C) as essential components under the condition that the isocyanate group becomes excessive with respect to the hydroxyl group. On the other hand, the condition in which the isocyanate group is excessive is specifically the composition ratio of the above compound [diisocyanate compound (A)
/ (Diol compound (B) and dimethylolalkanoic acid compound (C))], the equivalent ratio of the total amount of the isocyanate group in the diisocyanate compound, the hydroxyl group in the diol compound and the hydroxyl group in the dimethylolalkanoic acid compound is 1.
The conditions are in the range of 1 to 2.0, and more preferably 1.3 to 2.0.

The above reaction (polymerization) temperature is 50 to 150 ° C.
It is performed in the temperature range of. The polymerization reaction method may be bulk polymerization or solution polymerization. The solvent used in the case of solution polymerization is inert to isocyanate groups such as acetone, methyl ethyl ketone, tetrahydrofuran, and methyl acetate, has high miscibility with water, and
Those having a boiling point of 0 ° C. or lower are preferable. This is because with a solvent having a boiling point higher than 100 ° C., it becomes difficult to remove only the solvent out of the system from the dispersion obtained in the step after water dispersion.

In the present invention, the dimethylolalkanoic acid compound (C) converts the carboxyl groups introduced into the urethane prepolymer completely or partially into carboxylate groups to impart self-dispersibility to the polymer. It will be. Therefore, a basic compound is added as a so-called neutralizing agent to the urethane prepolymer before water dispersion. As such a neutralizing agent, ammonia or a volatile tertiary amine such as trimethylamine or triethylamine is preferably used. Since such a neutralizing agent can be removed by scattering during drying, the water resistance of the film does not decrease.

In this case, an alkali metal salt or a non-volatile amine can also be used as a neutralizing agent, but when these are used as the neutralizing agent, the neutralizing agent cannot be scattered and removed during drying, The water resistance of the coating tends to decrease. The addition amount of these neutralizing agents is preferably equal to or less than the equivalent amount of the dimethylolalkanoic acid compound (C) used. This is because if an equivalent amount or more of the neutralizing agent is used, the pH value of the obtained water dispersion becomes extremely large, and a stable water dispersion cannot be obtained.

To obtain the urethane-based water-based adhesive composition of the present invention, a step of dispersing in water a mixture obtained by uniformly mixing the urethane prepolymer, the neutralizing agent and the hydrophilic organic solvent is carried out. At this time, it is preferable to appropriately adjust the amount of the hydrophilic organic solvent used so that the viscosity of the mixture is 50,000 cps or less. This is because when the viscosity exceeds 50,000 cps, problems such as aggregation occur when the mixture is dispersed in water.

Further, it is necessary that the mixture is well mixed to form a homogeneous system. This is because if the mixture is a heterogeneous system, aggregation will occur during dispersion in water, the stability of the resulting urethane-based aqueous adhesive composition will decrease, and precipitation will occur. In such a case, the amount of the hydrophilic organic solvent used is appropriately adjusted so that the mixture becomes a homogeneous system.

As a method for dispersing the above mixture in water, water is gradually added to a compound having a mechanical shearing force such as a homomixer or a disper, or the mixture is gradually added to water having a shearing force. Both a batch method such as a method of adding and a continuous method of quantitatively supplying water and a mixture to various continuous emulsification dispersers and dispersing them can be adopted.

After the dispersion step or at the same time as the dispersion step, the urethane prepolymer is chain-extended. At this time, the diamino having two or more primary and / or secondary amino groups used as a chain extender is used. Examples of the compound include ethylenediamine, 1,4-butanediamine, 1,6-hexamethylenediamine, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, 1,3- (aminomethyl) cyclohexane, xylenediamine, piperazine. Etc.

The compounding amount of the above diamino compound is preferably equal to or less than the equivalent amount of the isocyanate group which is the origin of chain extension in the obtained urethane prepolymer. When the amount is equal to or more than the equivalent of the isocyanate group, the molecular weight of the chain-extended urethane prepolymer decreases and the cohesive force of the adhesive decreases. Also, chain extension with water is possible, and in this case, water as a dispersion medium also serves as a chain extender.

The volatile organic solvent added to the system at the time of polymerization or water dispersion can be removed from the system by means such as heating or depressurization after water dispersion. If a large amount of these organic solvents remains in the dispersion, the solvent resistance and heat resistance of the dry film are deteriorated and the working environment is deteriorated, which is not preferable.

An adhesion-imparting resin may be added to the urethane-based aqueous adhesive composition of the present invention for the purpose of further improving the adhesiveness. A conventionally known resin is used as the adhesion-imparting resin. For example, rosin-based resins such as gum rosin, tall oil rosin, wood rosin, polymerized rosin, hydrogenated rosin, disproportionated rosin, rosin ester, hydrogenated rosin ester, disproportionated rosin, disproportionated rosin ester, and rosin-modified phenolic resin. , Terpene resin, phenolic resin,
Terpene phenol resin, xylene resin, ketone resin,
Examples thereof include aliphatic petroleum resin, aromatic petroleum resin, alicyclic petroleum resin, coumarone resin, styrene resin and the like.

Among them, those which are preferably used are those modified with metaxylene and formaldehyde by a known method such as xylene resin and phenols such as phenol and alkyl-substituted bifunctional phenols such as para-t-butylphenol. Xylene resin, a ketone resin obtained by a known method from a ketone compound such as cyclohexane or methyl ethyl ketone and formaldehyde,
It is a novolak type phenol resin or an alkylphenol resin obtained by reacting phenol and, in some cases, an alkyl-substituted bifunctional phenol such as para-t-butylphenol with formaldehyde by a known method under an acid catalyst.

The above adhesion-imparting resins may be used alone or in combination of two or more, and the addition amount thereof is 100% of the urethane polymer.
It is preferably 5 to 200 parts by weight with respect to parts by weight. It is more preferably 5 to 150 parts by weight, and particularly preferably 10 to 100 parts by weight. If it is less than 5 parts by weight, the effect of improving the adhesiveness cannot be sufficiently obtained, and if it exceeds 200 parts by weight, the cohesive force at a high temperature is extremely decreased and the heat resistance is inevitably decreased.

The softening point of the adhesion-imparting resin is 60 to 16
It is preferably 0 ° C. As a method for adding the adhesion-imparting resin, a method of mixing an aqueous dispersion of the adhesion-imparting resin dispersed in water with an emulsifier with an aqueous dispersion of the urethane polymer, in an organic solvent solution of the urethane prepolymer before being dispersed in water The method of mixing the adhesion-imparting resin with the urethane prepolymer and then dispersing the mixture in water can be mentioned, but the latter method is preferable. This is because the former method requires a large amount of an emulsifier in order to obtain an aqueous dispersion of the adhesion-imparting resin, so that the water resistance of the adhesive decreases.

In obtaining the urethane-based aqueous adhesive composition of the present invention, a known cross-linking agent having a reaction activity with respect to the carboxyl group in the urethane polymer can be used. Examples thereof include isocyanate-based, melamine-based, aziridine-based, epoxy-based, oxazoline-based, carbodiimide-based, and various metal chelate-type cross-linking agents. Suitable examples include aziridine-based, epoxy-based, and carbodiimide-based compounds which are dissolved or dispersed in water.

Examples of the aziridine crosslinking agent include trimethylolpropane-tri-3-[(1-aziridinyl) propionate], diphenylmethane-bis-4,
4'-N, N'-diethylene urea, tetramethylol methane-tri-β-aziridinyl propionate, N,
N'-toluene-2,4-bis- (1-aziridinecarboxamide), N, N'-hexamethylene-1,6-
Examples thereof include bis- (1-aziridinecarboxamide).

Examples of the epoxy crosslinking agent include polypropylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol polyglycidyl ether, trimethylolpropane polyglycidyl ether, resorging glycyl ether, sorbitol polyglycidyl ether, sorbitan polyglycidyl ether, Polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether,
Examples include 1,6-hexanediol diglycidyl ether and the like.

The carboxylic diimide cross-linking agent is represented by the general formula R ⁶ -NC = NR ⁷ . In the formula, R ⁶ and R ⁷ represent hydrogen, a propyl group, a cyclohexyl group, a p-toluoyl group or the like.

In the present invention, further according to the purpose,
Plasticizers, fillers, thickeners, defoamers, fungicides and the like can be added.

The urethane-based aqueous adhesive composition of the present invention comprises
It can be used for adhesion of various adherends by methods such as coating, spraying and impregnation after adjusting it to an appropriate viscosity and concentration.

[0046]

In the urethane-based water-based adhesive composition of the present invention, the self-dispersing urethane polymer having pendant carboxyl groups in the polymer chain does not require an emulsifier when dispersed in water, and therefore has excellent water resistance. Will be. Furthermore, since a polyester polyol obtained from a dimer acid and an alkylene compound is used as a constituent component of the urethane polymer, it is excellent in heat resistance and hydrolysis resistance and has flexibility.

[0047]

【Example】

(Example 1) Polyester polyol consisting of dimer acid and ethylene glycol (OH value 86, number average molecular weight 1,200, "Pespol 200" manufactured by Toagosei Co., Ltd., hereinafter referred to as P-200) 50 parts by weight, polypropylene glycol polyol (OH Value 58, number average molecular weight 2,000
0, "Nissan Uniall D-2000" manufactured by NOF Corporation, hereinafter referred to as D-2000) 50 parts by weight, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate ("VESTANT-IPDI" manufactured by Huls, Inc., hereinafter 35.8 parts by weight of IPDI) and dimethylolpropionic acid (“DMPA” manufactured by Trimerit Technical Products Co., Ltd., hereinafter referred to as DMPA).
7 parts by weight [isocyanate group / hydroxyl group molar ratio = 1.
5] was added with 35.4 parts by weight of methyl ethyl ketone and stirred to carry out boiling point polymerization until the content of the isocyanate group became 2.5% by weight or less. 59.0 parts by weight of methyl ethyl ketone and 4.3 g of triethylamine as a neutralizing agent were added to adjust the viscosity.

Next, 200 g of the above mixture was added under vigorous stirring at room temperature, 300 parts by weight of water was added, and immediately thereafter, 25.4 parts by weight of a 10% by weight ethylenediamine aqueous solution was added. After further stirring for 1 hour at room temperature, the solvent was removed under reduced pressure. The solid content of the obtained urethane polymer aqueous dispersion was 35% by weight.

Example 2 P-200 in Example 1
Instead, a polyester polyol (OH value 98, number average molecular weight 1,200, "Pespol 600" manufactured by Toagosei Co., Ltd., hereinafter referred to as P-600) composed of dimer acid and 1,4-butanediol is used, and the addition amount thereof is used. An aqueous dispersion of a urethane polymer was obtained in the same manner as in Example 1, except that the addition amounts of the other components were as shown in Table 1.

(Example 3) P-200 in Example 1
Instead, a polyester polyol (OH value 56, number average molecular weight 2,000, "Pespol 601" manufactured by Toa Gosei Co., Ltd., hereinafter referred to as P-601) consisting of dimer acid and 1,4-butanediol is used, and the addition amount thereof is An aqueous dispersion of a urethane polymer was obtained in the same manner as in Example 1, except that the addition amounts of the other components were as shown in Table 1.

(Example 4) 50 parts by weight of P-601 and D
-2000 parts by weight 50 parts, IPDI 30.5 parts by weight,
And 5.5 parts by weight of DMPA [isocyanate group / hydroxyl group molar ratio = 1.5] and methyl ethyl ketone 34.0.
The mixed solution containing 1 part by weight was stirred and subjected to boiling point polymerization until the content of the isocyanate group was 2.3% by weight or less. Methyl ethyl ketone 56.
7 parts by weight and 4.2 g of triethylamine as a neutralizing agent,
Novolac alkylphenol resin (softening point 95 ° C,
"Hitanol 1501" manufactured by Hitachi Chemical Co., Ltd., hereinafter H-150
1) 50% by weight solution of methyl ethyl ketone 81.
6 parts by weight were added.

Next, 300 g of water was added to 200 g of the above mixture under vigorous stirring at room temperature, and immediately after that, 25.4 parts of a 10 wt% ethylenediamine aqueous solution was added. After further stirring for 1 hour at room temperature, the solvent was removed under reduced pressure. The solid content of the obtained urethane polymer aqueous dispersion was 35% by weight.

100 parts by weight of the obtained aqueous dispersion was added to an aqueous dispersion of an aziridine-based cross-linking agent (solid content 25%, "Chemite DZ-22-E" manufactured by Nippon Shokubai Co., Ltd., hereinafter referred to as DZ-22-E). .2 parts by weight was added to obtain an aqueous adhesive composition.

Comparative Example 1 P-200 in Example 1
And D-2000 instead of adipic acid and 1,6-hexanediol polyester polyol (OH value 55,
100 parts by weight of a number average molecular weight of 2,000 and "Nipporan 4073" manufactured by Nippon Polyurethane Industry Co., Ltd., hereinafter referred to as N-4073) were used, and the addition amounts of other components were as shown in Table 1 and the resulting water dispersion. 100 parts by weight of DZ-
22-E was added to 4.2 parts by weight to obtain an aqueous adhesive composition.

(Comparative Example 2) 50 parts by weight of P601 and D-
50 parts by weight of 2000, 30.5 parts by weight of IPDI, and 1,4-butanediol (reagent manufactured by Wako Pure Chemical Industries, Ltd.) 3.7.
Parts by weight [isocyanate group / hydroxyl group molar ratio = 1.5]
And 33.5 parts by weight of methyl ethyl ethyl ketone were stirred to carry out boiling point polymerization until the content of the isocyanate group became 2.3% by weight or less. Methyl ethyl ketone 55.9 was added to adjust the viscosity.

Next, 200 g of the above mixture was added with 300 parts by weight of a 1.2% by weight micellar solution of a nonionic emulsifier ("New Coal 210" manufactured by Nippon Emulsifier Co., Ltd.) with vigorous stirring at room temperature, and immediately thereafter. 22.8 parts by weight of a 10% by weight ethylenediamine aqueous solution was added thereto. After further stirring for 1 hour at room temperature, the solvent was removed under reduced pressure. The solid content of the obtained urethane polymer aqueous dispersion was 35% by weight.

An aqueous dispersion of an aziridine-based cross-linking agent (solid content 25%, "Chemite DZ-22-E" manufactured by Nippon Shokubai Co., Ltd., hereinafter referred to as DZ-22) was added to 100 parts by weight of the obtained aqueous dispersion 4.2. A part by weight was added to obtain an aqueous adhesive composition.

(Comparative Example 3) P-601 in Example 4
And D-2000 instead of 100 parts by weight of D-2000
Was used, and an aqueous dispersion of a urethane polymer was obtained in the same manner as in Example 4 except that the addition amounts of other components were as shown in Table 1.

With respect to the water dispersions obtained in Examples 1 to 4 and Comparative Examples 1 to 3, the water resistant adhesive strength and the like were evaluated by the following evaluation methods.

(1) Water-resistant adhesive strength The water dispersion was applied to a canvas and a cold rolled steel plate (width 2
5 mm, length 125 mm, was applied to a thickness of 2 mm) (coating amount: solid content 100 g / m ² with respect to the fabric, the solids content 40 g / m ² with respect to the steel plate), dried for 4 minutes at 80 ° C. air drying oven After that, roll pressure bonding (pressure 60 kg /
25 mm), and a test piece was prepared. After curing the obtained test piece for 1 week (23 ° C.), it was immersed in warm water of 40 ° C. for 12 hours, wiped with water, and subjected to a 90 ° peeling test (23
C., pulling speed 50 mm / min).

(2) Adhesion at high temperature The water dispersion was applied to a canvas (width 25 mm) using a brush (application amount: solid content 100 g / m ² ) and dried at room temperature for 48 hours. The adhesive layer surfaces of this canvas are 25m wide
m and length of 25 mm, and attach it to 80
A 180 ° peeling creep adhesion test piece was prepared by hot press bonding (pressure 10 kg / cm ² , 5 minutes) at ℃. A weight of 1 kg was dropped on the test piece, and the time for the weight to fall was measured under an atmosphere of 100 ° C.

(3) Hydrolysis resistance The water dispersion was cast and dried at room temperature for 1 week to prepare a urethane film having a thickness of 1 mm. This film is cut into a 50 × 50 mm test piece, which is cut at 50 ° C.
It was left for 60 days in an atmosphere with relative humidity of 90%, and its appearance change was observed.

The above measurement results are shown in Table 1. The compounds in the table are indicated by the above abbreviations.

[0064]

[Table 1]

As is clear from Table 1, the urethane-based water-based adhesive compositions of Examples 1 to 4 exhibit excellent room-temperature adhesiveness, water-resistant adhesiveness, heat-resistant adhesiveness and hydrolysis resistance.

[0066]

As described above, the urethane-based water-based adhesive composition of the present invention does not need to use an emulsifier at the time of production, and therefore has no deterioration in water resistance due to the emulsifier and is excellent in water resistance. Further, since it is obtained from the urethane polymer using the above-mentioned specific polyester polyol, a flexible adhesive having excellent heat resistance and hydrolysis resistance can be obtained.

Claims (1)

[Claims] 1. A polyisocyanate compound (A) having two or more isocyanate groups, a polyol compound (B) having two or more hydroxyl groups and having a molecular weight of 500 to 10,000, and a dimethylolalkanoic acid compound (C). ) Is an essential component, and these are reacted under conditions in which the isocyanate group is excessive with respect to the hydroxyl group, and the urethane prepolymer having an isocyanate group at the terminal is dispersed in water or after the dispersion, and the primary and / or 2 secondary amino groups
A urethane-based water-based adhesive composition containing a water dispersion of a urethane polymer obtained by chain-extending the urethane prepolymer with at least one diamino compound and / or water, the polyol compound (B) Is from 5% by weight to 100
A urethane-based water-based adhesive composition, characterized in that a weight% thereof is a polyester polyol obtained by a reaction of a dimer acid and an alkylene diol.