JPH11286668A - Aqueous adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an aq. adhesive compsn. which can solve the problems with toxicity, hazard and work environment caused by a solvent and the problems with sprayability of an aq. one-component type by compounding a rubber latex with a specified amt. of an amphoteric compd. and/or an adsorbent substance and by adjusting the pH of the compsn. to a specified value. SOLUTION: 100 pts.wt. (solid basis) rubber latex (e.g. an NR latex, an SBR latex, an IR latex, or a CR latex) is compounded with 0.05-50 pts.wt. amphoteric compd. (e.g. antimony oxide, EDTA, nitrilotriacetic acid, or glycine) and/or adsorbent substance (e.g. sepiolite, silica gel, or zeolite). The compsn. is adjusted to a pH of 6.0-11.0. The pH can be easily adjusted by adjusting the amt. of the amphoteric compd. and/or the adsorbent substance or by the addition of an alkali such as ammonia or sodium hydroxide. The compsn. is prepd. by charging first a rubber latex and then an amphoteric compd. and/or an adsorbent substance followed by stirring for 5-30 min.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based adhesive composition which is applied to both surfaces or one surface of an adherend, for example, by spraying, rolling or brushing, and the adhesive-applied surfaces are adhered to each other. More specifically, urethane foam used for molded parts represented by molded ceilings, molded doors and molded rears, which are interior materials for automobiles, polypropylene, vinyl chloride resin, polyethylene, polyurethane, polyvinyl alcohol-based synthetic fibers, polyester Adhesion of skin sheets made of fibers and other materials such as wood chipboard, polystyrene, painted metal plates, resin boards, corrugated cardboard, glass mats, or sofas, beds,
The present invention relates to a water-based adhesive composition used for bonding water-absorbing foam adherends, such as household articles such as chairs, toys such as stuffed animals, automobile articles, and toys such as stuffed animals. In the following description, a case where an adherend is mainly a foam will be described.

[0002]

2. Description of the Related Art Conventionally, for example, a rubber-based adhesive composition represented by polychloroprene has been used as an adhesive which is applied to both surfaces of an adherend by spraying or brushing, and the adhesive-applied surfaces are adhered to each other. Is dissolved in an organic solvent. However, an adhesive containing an organic solvent is highly harmful to the human body, and it is necessary to use equipment that does not diffuse the organic solvent as much as possible by using local exhaust equipment such as a hood. Further, at present, the workplace is used in a state where the organic solvent is full due to volatilization of the organic solvent contained in the bonded product. In addition, the organic solvent collected by a hood or the like is generally released into the atmosphere in some cases, and the odor of the solvent is dissipated from the factory, causing deterioration of the natural environment and water pollution.

On the other hand, as an adhesive containing no organic solvent,
Hot-melt adhesives and two-component adhesives have been developed.Hot-melt adhesives have a short bonding time and are effective for bonding simple diapers and sanitary products. Not suitable for bonding complex furniture and toys.
A number of attempts have been made on adhesives that do not contain water, and two-part adhesives are disclosed in, for example, JP-A-56-59.
No. 874 discloses a two-part adhesive.
When the two-component adhesive is applied by spraying, there are a method of mixing the adhesive in advance, a method of mixing with a sprayer tip, and a method of mixing on an adherend (overcoating, honeymoon), and the like. . However, in the method of mixing the adhesive in advance, the pot life of the adhesive and the initial bonding cannot be balanced, and in the method of mixing at the tip of the spray machine, the mixing ratio of the adhesive is not stable. The method of mixing on the body has problems such as unstable bonding work and cannot be used.

Further, there is a bonding method using a one-part type water-based adhesive as disclosed in Japanese Patent Application Laid-Open No. Hei 4-298536. There is a problem that it cannot be used continuously because of poor properties. Other conventional one-part water-based adhesives require drying equipment or require a long period of time to follow the process of drying and solidification, and are suitable for bonding large and complex furniture. Not available.

[0005]

SUMMARY OF THE INVENTION The present invention has been made on the background of the above-mentioned conventional technical problems, and solves the problems of harmfulness, danger, working environment, and water-based one-component spray workability due to a solvent. It is an object to provide a water-based adhesive composition that can be solved.

[0006]

According to the present invention, 0.05 to 50 parts by weight of an amphoteric compound and / or an adsorptive substance is compounded with respect to 100 parts by weight of a rubber-based latex in terms of solid content, and the pH is adjusted. The present invention provides an aqueous adhesive composition having a pH of 6.0 to 11.0.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The rubber latex used in the present invention includes natural rubber latex, styrene-butadiene rubber latex, styrene-butadiene-methyl methacrylate rubber latex, polychloroprene latex, butadiene-acrylonitrile rubber latex,
Butyl rubber latex, polyisoprene latex, styrene-isoprene rubber latex, and the like.
Of these rubber latexes, preferred are natural rubber latex, styrene-butadiene rubber latex, polychloroprene latex, and polyisoprene latex, and more preferred are natural rubber latex, polychloroprene latex, and polyisoprene latex. Natural rubber latex, polychloroprene latex, and polyisoprene latex, which are the rubber-based latexes mentioned last, have self-adhesiveness and therefore have particularly excellent initial adhesive strength. In addition, the polychloroprene latex can further improve the initial adhesive strength by selecting a high crystalline type. The above rubber-based latex can be used alone or in combination of two or more. The rubber-based latex has a solid content of 4
0 to 65% by weight, preferably 45 to 60% by weight, having a viscosity of 20 to 20,000 mpa · s, preferably 30 to 5,
A rubber-based latex of 000 mpa · s is preferred.

The rubber-based latex used in the present invention comprises:
Except for the natural rubber latex, the rubber component is prepared by an emulsion polymerization method, a re-emulsification method, a solution polymerization method, or the like. At this time, an anionic and / or nonionic emulsifier is used as an emulsifier. Among these emulsifiers, anionic emulsifiers having excellent emulsifying power are preferable, and fatty acid soap and rosin acid soap are more preferable. Among them, as the fatty acid soap, oleic acid, stearic acid, lauric acid, palmitic acid, myristic acid, sodium or potassium salts such as maleic acid,
The rosin acid soaps include the hydrogenated, disproportionated or dimerized sodium or potassium salts of abietic acid. The rubber-based latex obtained by using these anionic emulsifiers is excellent in the necessary stabilization in the coating step and the initial adhesive strength due to low contact pressure when bonding the adherend.

Next, the amphoteric compounds used in the present invention include amphoteric oxides such as zinc, cadmium, boron,
Oxides such as aluminum, gallium, indium, silicon, germanium, tin, lead, arsenic, antimony and bismuth; amphoteric hydroxides, zinc hydroxide, arsenic hydroxide, tin hydroxide; amphoteric electrolytes, ethylenediaminetetra Acetic acid, nitrilotriacetic acid, hydroxyethylethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, hydroxyethyliminodiacetic acid, dihydroxyethylglycine; Cystine, cystine, methionine, aspartic acid, glutamic acid, lysine, arginine, phenylalanine, tyrosine, histidine, tryptophan, broline, oxyproline, aminobutyric acid, Ntoraniru acid, m, p-aminobenzoic acid, such as proteins and the like, other, and amphoteric polymer compounds having a carboxyl group and an amino group, and the like amphoteric ion-exchange resin. These amphoteric compounds can be used alone or in combination of two or more.

The adsorptive substance used in the present invention includes silica gel, diatomaceous earth, allophane, talc,
Bentonite, potassium titanate, zeolite, sepiolite and the like can be mentioned. These adsorptive substances can be used alone or as a mixture of two or more.

In the present invention, by blending an amphoteric compound and / or an adsorptive substance with the rubber-based latex, it is possible to obtain the effect that the self-adhesiveness can be improved and the initial adhesive strength at the time of bonding can be improved. The amount of the amphoteric compound and / or adsorbent is 0.05 to 50 parts by weight, preferably 0.1 to 45 parts by weight, more preferably 5 to 40 parts by weight, based on 100 parts by weight of the solid content of the rubber latex. Parts by weight. If the amount is less than 0.05 part by weight, the self-adhesiveness of the aqueous adhesive composition is impaired, and the initial adhesive strength at the time of adhesion is weak. On the other hand, when the amount exceeds 50 parts by weight, the stability of the composition is deteriorated, and the self-adhesiveness is impaired due to the decrease in the latex content, and the initial adhesive strength and cohesive strength are insufficient, which is not preferable. No reasonable performance is obtained.

Further, the pH of the aqueous adhesive composition of the present invention
Is 6.0 to 11.0, preferably 6.5 to 10.5,
More preferably, it is 7.0 to 10.0. Composition p
When H is less than 6.0, the stability of the composition is deteriorated, and gelation occurs during storage. Even if gelling does not occur, the composition may gel or coagulate under the slight pressure during application of the adhesive. This is not preferable because the coating workability is significantly impaired. On the other hand, p
If H is higher than 11.0, the self-adhesiveness of the composition is impaired, and the initial adhesive strength at the time of adhesion is unfavorably deteriorated.
The pH value of the composition can be easily adjusted by means such as adding the amphoteric compound and / or the adsorptive substance, or adding an alkali compound such as ammonia or sodium hydroxide.

The water-based adhesive composition of the present invention may contain various emulsions such as an acrylic resin emulsion, a styrene-acryl resin emulsion, a vinyl acetate resin emulsion, and a vinyl chloride resin emulsion for the purpose of improving performance. , A plasticizer, a tackifier resin, an antifoaming agent, a stabilizer, an antioxidant, a preservative, a thickener, and a coloring agent. The amount of these additives is
It is preferably 40 parts by weight or less, more preferably 0.1 to 30 parts by weight, based on 100 parts by weight of the solid content of the rubber latex. If the amount exceeds 40 parts by weight, the self-adhesiveness of the composition decreases, and the initial adhesive strength deteriorates, which is not preferable.

In order to prepare the water-based adhesive composition of the present invention, usually, a rubber-based latex, an amphoteric compound and / or an adsorptive substance are added in this order and stirred for about 5 to 30 minutes. Further, to adhere the adherend using the water-based adhesive composition of the present invention, to apply to both sides or one side of the adherend, using a spray, a roll, a brush or the like, and to adhere the adherend use.

The water-based adhesive composition of the present invention can be used for urethane foam, polypropylene, polyvinyl chloride, polyethylene, polyurethane which is used in molded parts represented by molded ceilings, molded doors and molded rears, which are important interior materials for automobiles. Adhesion of skin sheets made of polyvinyl alcohol-based synthetic fibers, polyester fibers, etc. to base materials such as wood chipboard, polystyrene, painted metal plates, resin boards, cardboard, glass mats, or sofas, beds,
It is useful for bonding between foam-adhered materials having a water-absorbing property, such as household articles such as chairs, toys such as stuffed animals, automobile articles, and toys such as stuffed animals.

[0016]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples. In the examples, parts and% are by weight unless otherwise specified. Various measurements in the examples are as follows.

(1) Measurement of pH value The prepared adhesive was measured using a glass electrode type hydrogen ion concentration meter (manufactured by Toa Denpa Kogyo Co., Ltd.). (2) Emulsion Stability After preparing the adhesive, it was filtered through a 200-mesh stainless steel wire mesh, and the amount of aggregates was determined. ；: Less than 3% of the aggregate of the adhesive generated Δ: 3% or more and less than 5% of the adhesive, ×: more than 5% of the aggregate of the adhesive

(3) Spray suitability The prepared adhesive was applied using a spray gun (Iwata W-77, caliber = 2 mmφ) for 10 minutes at a maximum discharge rate (air pressure of 50 pa), and the applicability and the gun Clogging was determined. ；: Spray coating can be performed without clogging in the gun for 10 minutes or more. Δ: Spray coating can be performed without clogging in the gun for 5 minutes or more and less than 10 minutes. ×: In less than 5 minutes, clogging of the inside of the gun occurs, and spray coating cannot be performed.

(4) Initial adhesive strength The produced adhesive was spray-coated (50 g / m2) on urethane foam (polyether-based soft 80-fold foam).
² and WET), the coated surfaces were immediately bonded together and pressure-bonded (30 g / cm ² ), and immediately thereafter, the adhesive strength was judged by the feel of the hand. ○: Adhesion is possible immediately after application △: Adhesion is possible 2 minutes after application ×: Adhesion is possible 5 minutes after application

(5) Room-Temperature Adhesive Strength The prepared adhesive is spray-coated (50 g / m 2) on urethane foam (polyether-based soft 80-fold foam).
^2, WET) was then, it is crimped by bonding the coated surface to each other after 5 minutes (30g / cm ^2), after crimping, after standing at 20 ° C. 24 hours for 180 ° peel measured at 200 mm / min. ；: Adhesive strength is as strong as 900 g / 25 mm or more. Δ: Adhesion force of 600 g / 25 mm or more, 900 g / 25
x: Weak, with an adhesive strength of less than 600 g / 25 mm.

(6) Water-resistant adhesive strength The produced adhesive is spray-coated (50 g / m2) on urethane foam (polyether-based soft 80-fold foamed foam).
^2, WET) was then crimping by bonding the coated surface to each other after 5 minutes is (30g / cm ^2), after crimping, after standing at 20 ° C. for 24 hours, 24 hours, the adhesive was then cured in water at 20 ° C. Immediately at 200 mm / min while containing water
An 80 ° peel measurement was performed. ；: Adhesive strength is strong at 700 g / 25 mm or more. Δ: Adhesion force of 500 g / 25 mm or more, 700 g / 25
x: Weak, with an adhesive strength of less than 500 g / 25 mm.

(7) Heat-resistant adhesive strength The produced adhesive is spray-coated (50 g / m2) on urethane foam (polyether-based soft 80-fold foam).
^2, WET) was then, after 5 minutes, allowed bonding the coated surface to each other crimping (30 g / cm ²⁾ is, after pressure bonding, 2 at 20 ° C.
After standing for 4 hours, the adhesive was cured at 80 ° C. for 24 hours, and immediately 180 ° peeling measurement was performed at 200 mm / min without cooling. ；: Adhesive strength is strong at 500 g / 25 mm or more. Δ: Adhesion force of 350 g / 25 mm or more, 500 g / 25
×: less than 350 g / 25 mm.

(8) Adhesive layer texture The prepared adhesive is spray-coated (50 g / m2) on urethane foam (polyether-based soft 80-fold foam).
^2, WET) was then, is crimped by bonding the coated surface to each other after 5 minutes (30g / cm ^2), after crimping, after standing at 20 ° C. 24 h, it was determined by finger touch. ；: The texture of the urethane foam and the adhesive layer is equal. Δ: The texture of the adhesive layer is slightly harder than urethane foam. X: The adhesive layer is harder than urethane foam.

The components used in the examples are shown below. Rubber-based latex A; natural rubber latex (NR latex) [JLX113, manufactured by Resitex Corporation] B: styrene-butadiene rubber latex (SBR latex) [JSR 056, manufactured by JSR Corporation]
1] C; polyisoprene latex (IR latex) [manufactured by Sumitomo Seika Co., Ltd., IR-900] D: polychloroprene latex (CR latex)
[OL-0040, manufactured by Denki Kagaku Kogyo KK] E: Acrylic resin emulsion (AR emulsion)
[AE333, manufactured by JSR Corporation]

Amphoteric compound a: ethylenediaminetetraacetic acid [manufactured by Kyrest Co., Ltd.
Nitrilotriacetic acid [Cylest 3A];
T] c; antimony oxide [A255, manufactured by Nissan Chemical Industries, Ltd.
0L] d; Glycine [Showa Denko KK] adsorptive substance e; Sepiolite [Showa Mining Co., Ltd., Aidplus] f; Silica gel [Fuji Silysia Chemical Ltd., Sylysia 450] g; Zeolite [Japan Chemical Industry Co., Ltd., CX110
P] Other additives h; dibutyl sebacate [manufactured by Daihachi Chemical Industry Co., Ltd., DB
S] i; Methylcellulose [Shin-Etsu Chemical Co., Ltd., Metrose 90SH4000]

Examples 1 to 23 and Comparative Examples 1 to 13 Using the rubber latexes A to E and the additives a to i, adhesive compositions were prepared according to the formulations shown in Tables 1 to 5. did. Table 1 shows the emulsion stability, spray suitability, initial adhesive strength, room temperature adhesive strength, water resistant adhesive strength, heat resistant adhesive strength, adhesive layer texture, and pH value of these adhesive compositions.
Are shown in FIGS. In Tables 1 to 5, the number of parts of rubber-based latex (100 parts) is in terms of solid content. As is clear from Tables 1 to 3, Examples 1 to 23 have achieved the performances aimed at by the present invention. In contrast, Comparative Example 1 in Tables 4 and 5
, 2, 8 to 9, and 11, the pH value of the composition is out of the range of the present invention, and the initial adhesive strength and the water resistant adhesive strength are inferior. Comparative Examples 3 to
In Nos. 4, 12 and 13, the amphoteric compound and / or the adsorptive substance are out of the range of the present invention, and the initial adhesive strength and the water / heat resistant adhesive strength are inferior. In Comparative Examples 5 to 7, and 10, the rubber latex was out of the range of the present invention, and the initial adhesive strength was poor.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

[Table 3]

[0030]

[Table 4]

[0031]

[Table 5]

[0032]

The water-based adhesive composition of the present invention has the following properties: initial application after being applied to an adherend for a short time at low temperature and room temperature; and heat resistance, water resistance and durability required for the adhesive. sex,
And it has the performance of excellent texture and workability of the adhesive layer after bonding. Therefore, when the aqueous adhesive composition of the present invention is applied to an adherend by spraying or the like and used as an adhesive, the following effects are obtained. Since it is water-based, it does not contain solvents, and there is no risk of toxicity or pollution. Because of the one-pack type, coating work and work management are easy. During spray coating, the adhesive does not clog the inside of the gun, and the coating operation is easy. Excellent initial adhesion and short lamination work. Since the adhesive layer is relatively soft, the texture is not impaired.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshiaki Yonekawa 2-3-1 Nihombashi, Chuo-ku, Tokyo Inside E-Tech Co., Ltd.

Claims (1)

[Claims] 1. A rubber-based latex having a solid content of 100
0.05 to 50 parts by weight of an amphoteric compound and / or an adsorptive substance is blended with respect to parts by weight, and the pH is 6.0 to 6.0.
An aqueous adhesive composition which is 11.0.