JP3350952B2 - Two-part water-based adhesive composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-pack type water-based adhesive composition which is used for various kinds of bonding and has good heat resistance, good water resistance and a long working life.

[0002]

2. Description of the Related Art Conventionally, emulsion adhesives such as vinyl acetate emulsions and acrylic emulsions and chloroprene and styrene latex adhesives have been widely used as water-based adhesives because of their simplicity of operation. ing. In order to improve the heat resistance and water resistance of such an aqueous adhesive, an isocyanate compound, phenol /
Many studies have been made on mixing a formaldehyde compound and the like to introduce a curing reaction into the bonding process.

[0003] For example, Japanese Patent Publication No. Sho 51-30576,
An aqueous vinyl urethane adhesive composition in which isocyanate is dispersed in an emulsion containing an aqueous polyvinyl alcohol solution described in JP-B-51-30577, and a vinyl acetate emulsion described in JP-B-45-39358 And an adhesive composition mixed with a modified phenol / formaldehyde compound.

Further, an adhesive composition comprising a crosslinkable emulsion having a crosslinking point introduced into the emulsion itself and a crosslinking agent capable of undergoing a crosslinking reaction with the crosslinking point has been studied. For example, JP-B-46-30946. The gazette discloses an adhesive composition comprising an amino group-containing polymer emulsion obtained by modifying a carboxyl group-containing polymer emulsion with an alkylene imine, and an epoxy group-containing polymer emulsion.

[0005] However, emulsion adhesives such as vinyl acetate emulsions and acrylic emulsions and chloroprene and styrene latex adhesives have problems in terms of water resistance. In the case of the mixture, a heating step is required, and generation of formaldehyde becomes a problem. Aqueous vinyl urethane is excellent in terms of adhesiveness and water resistance, but the foaming and thickening of the adhesive is remarkable, the usable time is short, and the coating workability is poor. Furthermore, an adhesive comprising an amino group-containing polymer emulsion having an active hydrogen and an epoxy group-containing polymer emulsion is a reaction between the polymer emulsions, so that a crosslinking reaction becomes insufficient and a sufficient adhesive force cannot be obtained.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a two-part water-based adhesive composition which has a long working time, cures at room temperature, and exhibits excellent adhesiveness and water resistance.

[0007]

Means for Solving the Problems The present inventors diligently studied the drawbacks of the conventional adhesive in consideration of the above-mentioned circumstances, and reached the present invention.

That is, the present invention relates to (a) an amino group-containing polymer emulsion in which a carboxyl group-containing polymer is modified with an alkyleneimine, and (b) a water-soluble polyhydric epoxy having an average molecular weight of 1,000 or less. The present invention relates to a two-part aqueous adhesive composition containing a compound as an essential component.

Hereinafter, the constitution of the two-part water-based adhesive composition of the present invention will be described in more detail. The state of the polymer containing a carboxyl group used in the present invention is not particularly limited, and examples thereof include an emulsion, an aqueous resin, and a state in which a water-insoluble bulk polymer is neutralized with a basic substance. However, preferred in the present invention are emulsions.

The polymer emulsion containing a carboxyl group in the present invention includes a polymerizable monomer (A) containing a carboxyl group and another polymerizable monomer copolymerizable with the monomer (A). A copolymer with the compound (B) can also be used. In consideration of the balance of the performance of the adhesive, it is preferable to copolymerize the monomer (B) rather than the monomer (A) alone.

As the monomer (A), monocarboxylic acids such as (meth) acrylic acid, cinnamic acid and crotonic acid; unsaturated dicarboxylic acids such as itaconic acid, maleic acid and fumaric acid and monoesters thereof; And one or a mixture of two or more selected from the group of unsaturated monomers containing a carboxyl group.

As the monomer (B), (meth) acrylamide, N-methylol (meth) acrylamide, 2-
Hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, Isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, (meth)
Acrylonitrile, styrene, α-methylstyrene, vinyl acetate, vinyl propionate, (meth) acrolein, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, butadiene,
One type or a mixture of two or more types selected from the unsaturated monomer group having no carboxyl group such as ethylene and propylene is exemplified.

As a method for obtaining a polymer emulsion containing a carboxyl group from the monomers (A) and (B), a known method is used. For example, in the presence of a polymerization catalyst such as potassium persulfate, And emulsion polymerization performed in water using a nonionic surfactant or the like. The amount of the carboxyl group (—COOH) of the obtained carboxyl group-containing polymer emulsion is required to be 2% by weight or more as the monomer (A), and preferably 2.5 to 15% by weight.

Examples of the carboxyl group-containing emulsion include carboxyl group-containing acrylic emulsion, carboxyl group-containing styrene-acryl emulsion, carboxyl group-containing vinyl acetate emulsion, carboxyl group-containing vinyl acetate-ethylene emulsion, and carboxyl group-containing emulsion. Containing SBR latex, carboxyl group-containing butadiene-acrylonitrile latex and the like are industrially manufactured, and these can also be used.

In the polymer emulsion containing a carboxyl group, a monomer having two or more copolymerizable unsaturated moieties in one molecule such as divinylbenzene is introduced in the above-mentioned emulsion polymerization step. An emulsion obtained by internally crosslinking an emulsion, a polymer obtained by controlling the degree of polymerization using a chain transfer agent such as t-dodecyl mercaptan, or a multilayer structure (core-shell) obtained by sequentially polymerizing a mixture of two or more kinds of monomers. (Type) emulsion, or emulsion polymerization by a known method such as a power feed method.

[0016]

Examples of the alkyleneimine for modifying the carboxyl group-containing polymer used in the present invention include ethyleneimine, propyleneimine,
Butylene imine; and N- (2-aminoethyl) aziridine, N- (2-aminopropyl) aziridine, N- (2-aminoethyl) propyleneimine and the like.
-(2-aminoalkyl) -substituted alkyleneimines can also be mentioned.

The amount of the alkylene imine to be used is preferably in the range of 0.2 to 2.5 moles, more preferably 0.5 to 1.5 moles, per carboxyl group in the polymer. An amino group-containing polymer having active hydrogen is produced by adding and reacting these alkylene imines to a carboxyl group-containing polymer. In the present invention, an amino group-containing polymer emulsion is preferable. The amino group-containing polymer emulsion may be used alone or as a mixture of two or more.

The average molecular weight used in the present invention is 1,000.
The following water-soluble polyvalent epoxy compounds have an average molecular weight of 100 or more containing two or more epoxy groups in one molecule.
There is no particular limitation as long as it is a water-soluble epoxy compound of 0 or less. And epichlorohydrin in the presence of a basic catalyst. These water-soluble polyvalent epoxy compounds can be used alone or as a mixture of two or more.

The water-soluble polyepoxy compound is mixed with the amino group-containing polymer emulsion as it is or after being diluted with water. The amount of the water-soluble polyhydric epoxy compound used is preferably in the range of 0.5 to 6.0 times, more preferably 0.75 times, as the epoxy equivalent ratio (epoxy equivalent / amine hydrogen equivalent of the amino group-containing polymer). ~ 4.0 times. When the amount of the water-soluble polyvalent epoxy compound used is 0.5 or less in epoxy equivalent ratio, the curing reaction portion is small, so that the improvement in water resistance and heat resistance is insufficient, and 6.0.
In the above case, the pot life after mixing becomes shorter,
Since many unreacted water-soluble polyvalent epoxy compounds remain, the water resistance and the like are lowered.

The adhesive composition according to the present invention may further comprise, in addition to the above essential components, vinyl acetate emulsion, vinyl acetate and unsaturated acids such as (meth) acrylic acid, maleic acid, fumaric acid, crotonic acid and ester compounds thereof. Copolymer emulsions, ethylene-vinyl acetate copolymer emulsions, acrylic-styrene-based copolymer emulsions such as (meth) acrylate-styrene copolymer emulsions, etc., and ethylene-butadiene latex, butadiene-acrylonitrile latex, Synthetic resin emulsions such as chloroprene latex and butyl rubber latex and synthetic rubber latex may be added alone or in combination as appropriate, and rosins, alkylphenol resins and petroleum resins as well-known tackifiers, and high boiling organic compounds Solvent and plastic Coalescents the like, flour, fillers such as starch and corn starch, clay, talc, calcium carbonate, filler such as titanium oxide, red iron oxide and bentonite, primarily cellulose which is used as a thickening agent, hydroxyethyl cellulose, and C
Natural polymers such as cellulose derivatives such as MC and synthetic polymers such as polyvinyl alcohol and polyvinyl alcohol derivatives, preservatives, insect repellents, defoamers and the like can be appropriately added and used.

The adhesive composition may be used for plywood or for secondary processing, woodworking, construction and structural glued laminated materials, particle board, resin such as a soft vinyl chloride resin sheet, paper,
Effective as wood bonding for decorative boards by laminating cloth, metal foil, etc. with wood, resin such as polyester film, paper, cloth or various adhesives for laminating these with other base materials such as steel plate. Adhesive composition.

In the present invention, (a) an amino group-containing polymer emulsion obtained by modifying a carboxyl group-containing polymer with an alkylene imine; and (b) a water-soluble polyepoxy compound having an average molecular weight of 1,000 or less. By using the two-component water-based adhesive composition as an essential component, it is possible to provide an adhesive that can be used for a long time, cures at room temperature, and has excellent adhesiveness and water resistance.

[0024]

EXAMPLES Hereinafter, embodiments of the present invention will be described specifically with reference to examples. The present invention is not limited to these Examples. In the examples,
Parts indicate parts by weight, and percentage (%) indicates% by weight.

Reference Example 1 398 parts of deionized water and 40 parts of an anionic surfactant (25% aqueous solution) were placed in a 1-liter separable flask equipped with a stirrer, a reflux condenser, a thermometer, a nitrogen inlet tube and a dropping funnel. And then heated to 68 ° C. while introducing nitrogen. A polymerizable monomer mixture consisting of 48 parts of acrylic acid, 184 parts of styrene, 57 parts of methyl methacrylate and 111 parts of butyl acrylate was added to a 40-part flask and stirred for 15 minutes.
4.6 parts of a 75% aqueous hydrogen peroxide solution and 4.2 parts of a 3% 1-ascorbic acid aqueous solution were added to initiate polymerization.

From 15 minutes after the start of the polymerization, the remaining polymerizable monomer mixture was dropped uniformly over 90 minutes. 1.75 during this time
41 parts of a 37% aqueous hydrogen peroxide solution and 37 parts of a 3% aqueous L-ascorbic acid solution were divided and dropped into the flask every 10 minutes until the dropping of the polymerizable monomer mixture was completed. After completion of the dropwise addition, the mixture was aged for 1 hour and cooled to obtain a carboxyl group-containing polymer emulsion having a nonvolatile content of 44.5%. Then this emulsion 150
47.8 parts of a 10% aqueous solution of ethyleneimine was added in two portions with stirring, and the mixture was reacted at 50 ° C. for 2 hours to obtain a nonvolatile content of 36.2 parts.
% Of a polymer emulsion containing aminoethyl groups was obtained.

Reference Example 2 48 parts of acrylic acid, 138 parts of styrene, methyl methacrylate
A carboxyl group-containing polymer emulsion was polymerized using the apparatus and polymerization conditions shown in Reference Example 1 except that a polymerizable monomer mixture consisting of 57 parts and 157 parts of butyl acrylate was used. An aminoethyl group-containing polymer emulsion was obtained by operation using ethyleneimine.

Reference Example 3 Acrylic acid 32 parts, styrene 144 parts, methyl methacrylate
A carboxyl group-containing polymer emulsion was polymerized using the apparatus and polymerization conditions shown in Reference Example 1 except that a polymerizable monomer mixture consisting of 60 parts and 164 parts of butyl acrylate was used. An aminoethyl group-containing polymer emulsion was obtained by operation using ethyleneimine.

[0029]

Reference Example 4 A glycidyl group-containing polymer emulsion was prepared in the same apparatus and under the same polymerization conditions as in Reference Example 1 except that 48 parts of glycidyl methacrylate was used instead of acrylic acid in the polymerizable monomer mixture of Reference Example 2. I got

Example 1 To 100 parts of the aminoethyl group-containing polymer emulsion obtained in Reference Example 1, 8 parts of trimethylolpropane polyglycidyl ether was added and uniformly mixed to obtain a nonvolatile matter content of 40.9%.
Was obtained. The obtained adhesive is applied to an adherend made of a birch material so as to have a coating amount of 150 g / m ² , and bonded together. Temperature: 25 ° C., pressing pressure: 10 kg / cm ² , pressing time: 1 hour Were adhered under the following conditions. Further, at a temperature of 25 ° C. and 60% RH,
After curing for one day, the normal adhesive strength and the boiling adhesive strength after repeated boiling treatment were measured as compression shear adhesive strength (kgf / cm ² ) according to JIS K-6852. Table 2 shows the results.

Examples 2 and 3 Using the aminoethyl group-containing polymer emulsions obtained in Reference Examples 1 and 2, an adhesive having the composition shown in Table 1 was obtained in the same manner as in Example 1. Further, the measurement of the adhesive strength of wood using these adhesives was performed in the same manner as in Example 1. Table 2 shows the results.

Comparative Example 1 Using the aminoethyl group-containing polymer emulsion obtained in Reference Example 1, an adhesive having the composition shown in Table 1 was obtained in the same manner as in Example 1. Further, the measurement of the adhesive strength of wood using these adhesives was performed in the same manner as in Example 1. Table 2 shows the results.

Comparative Example 2 An aqueous vinyl urethane-based adhesive having a non-volatile content of 46.8% after mixing and mixing with a crosslinking agent was used as Comparative Example 2. Except for using this adhesive, the adhesive strength of wood was measured in the same manner as in Example 1. Table 2 shows the results.

[0035]

[Table 1]

[0036]

[Table 2]

Example 4 To 100 parts of a vinyl acetate-ethylene copolymer emulsion (Sumikaflex 400, manufactured by Sumitomo Chemical Co., Ltd.), 40 parts of the aminoethyl group-containing polymer emulsion of Reference Example 2 and 2 parts of dibutyl phthalate were added. Was mixed. After mixing, 3 parts of glycerol polyglycidyl ether was added and uniformly mixed to obtain an adhesive. Apply 150 g / m ^{2 of the} obtained adhesive
Apply evenly to a base plate (12m / m ordinary plywood, JAS type 1 applicable Lauan plywood), paste polyethylene foam (lion board, foam, slightly coarse one), temperature: 20 ° C, pressing pressure: 0.5 kg / cm ² , pressing time: 10
Bonded under conditions of minutes. Further, at 20 ° C. and 60% RH,
After curing for one day, the adhesive was evaluated by the following evaluation method. The adhesive was stored in an atmosphere at 30 ° C., and the pot life was measured by the following method. The results are shown in Table 4.

[Evaluation method] Adhesion test: Plane tension (kg / cm ² ) and pulp fracture at that time were measured. Water resistance test; JAS 1 class immersion peel test. Evaluation criteria ◎: No appearance abnormality △; Partial shrinkage or peeling ×; Vigorous shrinkage or peeling Pot life: The point at which the viscosity of the adhesive showed a value of twice or more immediately after compounding was taken as the pot life (pot life). did.

Example 5 Using the aminoethyl group-containing polymer emulsion obtained in Reference Example 3, an adhesive having the composition shown in Table 3 was obtained in the same manner as in Example 4. Further, the adhesive force using these adhesives was measured in the same manner as in Example 4. Table 4 shows the results.

Comparative Examples 3 and 4 The adhesive compositions shown in Table 3 were obtained in the same manner as in Example 4. The adhesive strength of these adhesives was measured in the same manner as in Example 4. Table 4 shows the results.

Comparative Example 5 The two-part aqueous vinyl urethane-based adhesive used in Comparative Example 2 was used as Comparative Example 5. Except for using this adhesive, the adhesive strength was measured in the same manner as in Example 4. Table 4 shows the results.

[0042]

[Table 3]

[0043]

[Table 4]

Example 6 Polyvinyl alcohol having a polymerization degree of 1700 and a saponification degree of 88 mol% was used.
To 100 parts of a vinyl acetate polymer emulsion having a nonvolatile content of 10% and a nonvolatile content of 45%, 10 parts of the aminoethyl group-containing polymer emulsion of Reference Example 1 and 5 parts of dibutyl phthalate were added and mixed uniformly. After mixing, 1 part of glycerol polyglycidyl ether was added and uniformly mixed to obtain an adhesive. The resulting adhesive a coating amount 70 g / m ² was as base paper for paper tube (1.0 m
m), adhered under a deposition time of 3 minutes, adhered under the conditions of temperature: 20 ° C., pressing pressure: 5 kg / cm ² , pressing time: 30 seconds, according to JIS K-6850 A test piece for a tensile shear adhesive strength test was prepared. In addition, 20
After curing for 3 days at 60 ° C. and 60% RH, the adhesive material was subjected to a tensile shear adhesive strength (tensile speed 5 mm) according to the following evaluation method.
/ Min). Further, the adhesive was stored in an atmosphere at 30 ° C., and the evaluation of the adhesive strength after one day had been performed was similarly performed. Table 6 shows the results.

[Evaluation method] Normal condition: Post-curing test under the above conditions. Boiling resistance: After curing under the above conditions, 20
Immerse for a minute, cool in cold water and test wet.

Example 7 Using the aminoethyl group-containing emulsion obtained in Reference Example 2, an adhesive having the composition shown in Table 5 was obtained in the same manner as in Example 6. Further, the adhesive strength of these adhesives was measured in the same manner as in Example 6. Table 6 shows the results.

Comparative Examples 6 and 7 The adhesive compositions shown in Table 5 were obtained in the same manner as in Example 6. The adhesive strength of these adhesives was measured in the same manner as in Example 6. Table 6 shows the results.

Comparative Example 8 The two-part aqueous vinyl urethane-based adhesive used in Comparative Example 2 was used as Comparative Example 8. The adhesive strength was measured in the same manner as in Example 6 except that this adhesive was used. Table 6 shows the results.

[0049]

[Table 5]

[0050]

[Table 6]

Example 8 The aminoethyl group-containing emulsion 10 obtained in Reference Example 2
To 0 parts, 8 parts of trimethylolpropane polyglycidyl ether was added and mixed uniformly to obtain an adhesive having a nonvolatile content of 40.9%. The obtained adhesive is applied to a galvanized steel sheet so that the coating thickness when dried is 6 μm, and the temperature of the steel sheet is 30 seconds.
Heating was performed for 30 seconds in an oven set to 200 ° C. to remove volatile components and melt the adhesive. Immediately after heating, the sheet was bonded to a polyvinyl fluoride film (Tedlar, brown, manufactured by DuPont) at a bonding line pressure of 10 kgf / cm. After curing for 3 days at a temperature of 25 ° C. and a relative humidity of 60%, the adhesion between the steel sheet and the laminate of the polyvinyl fluoride film was evaluated by the following method. The results are shown in Table 8.

[Evaluation Method] Adhesion: A parallel cut having a width of 5 mm reaching the steel sheet from the polyvinyl fluoride film side was cut at a right angle, and extruded 7 mm with an Erichsen tester. Evaluation criteria ◎: No peeling of film at all △: Square part at the top is slightly peeled ×: Square part at the top is completely peeled

Example 9 and Comparative Examples 9 and 10 Using the aminoethyl group-containing polymer emulsion obtained in Reference Example 2, an adhesive having the composition shown in Table 7 was obtained. Further, these adhesives were evaluated for adhesiveness in the same manner as in Example 8. Table 8 shows the results.

[0054]

[Table 7]

[0055]

[Table 8]

Example 10 The same adhesive obtained in Example 8 was applied to a soft polyvinyl chloride film (canvas: soft polyvinyl chloride + nonwoven fabric) so that the coating thickness when dried was 6 μm. Temperature reached in 60 seconds for the above soft polyvinyl chloride film coated with adhesive
After heating to 100 ° C and heating with a nip roll with a linear pressure of 5 kgf / cm, the polyvinyl fluoride film (Tedlar, transparent,
(Made by DuPont). Further, they were pressed by a hot press at 120 ° C. at a pressure of 6 kgf / cm ² for 15 seconds. Temperature 25 ° C, 60
After curing at 24% RH for 24 hours, the following adhesiveness was evaluated. The results are shown in Table 9.

[Evaluation Method] Adhesion: The adhesive end of the laminate of the polyvinyl chloride film and the polyvinyl fluoride film was forcibly peeled off, and the laminate was rubbed by hand 100 times to evaluate the adhesion. Evaluation criteria ◎: No peeling in both forced peeling and hand rubbing △: Peeling out by hand rubbing ×: Peeling out by forced peeling Heat and humidity resistance test: Temperature: 80 ° C, Humidity: One month in a thermo-hygrostat set at 95% RH After storage, the above adhesiveness was evaluated.

Example 11 and Comparative Examples 11 and 12 The same adhesiveness as in Example 10 was evaluated using an adhesive having the same composition as in Example 9 and Comparative Examples 9 and 10, respectively. 11, 12. Table 9 shows the results.

[0059]

[Table 9]

[0060]

As is clear from the examples, the present invention provides an active hydrogen-containing amino group-containing polymer emulsion obtained by modifying a carboxyl group-containing polymer with an alkyleneimine, and an average molecular weight of 1,000. By using a two-part water-based adhesive composition containing the following water-soluble polyepoxy compound as an essential component, the workability is better than conventional adhesives, the usable time is longer, and curing is performed at room temperature. Thus, an adhesive composition capable of forming an adhesive layer having excellent adhesiveness and water resistance can be provided.

Continuation of the front page (56) References JP-A-3-205472 (JP, A) JP-A-2-69587 (JP, A) JP-A-63-12620 (JP, A) JP-A-58-45223 (JP) JP-A-54-77644 (JP, A) JP-B-46-30946 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C09J 163/00

Claims (1)

(57) [Claims] 1. A (a) amino group-containing polymer emulsion in which a carboxyl group-containing polymer is modified with an alkylene imine; and (b) an average molecular weight of 1
A two-part water-based adhesive composition comprising a water-soluble polyepoxy compound having a molecular weight of 000 or less as an essential component.