JPH04180982A - Rapidly curable water-base adhesive and method of bonding - Google Patents

Abstract

PURPOSE:To make it possible to cure in a very short time to thereby effect bonding with both excellent initial adhesion and excellent permanent bonding strength after drying by applying liquid A comprising an aqueous solution of a specified resin and liquid B comprising a specified resin respectively to the surface of one adherent and that of the other, and putting the coated surfaces together for joining. CONSTITUTION:Liquid A comprising an aqueous solution of a polyvinyl alcohol resin having acetoacetyl groups (e.g. one obtained by dispersing polyvinyl alcohol in acetic acid and adding diketene thereto) and liquid B comprising a polyaminopolyamide resin having at least two amino and two amino groups in the molecule (e.g. a condensate of a dimer acid obtained from a fatty acid derived from drying oil, semidrying oil, etc., with a polyamine) are applied respectively to the surface of one adherent (e.g. wood, paper or an inorganic material) and that of the other, and the coated surfaces are put together to effect bonding. This gives a very excellent initial adhesion. Merely by allowing to stand after clamping them for a short time, a high adhesive power can be obtained and a permanent water-resistant adhesive power can be revealed. Also, since the curing agent hardly penetrates into the adherends, a good bonded object can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a fast curing water-washing adhesive and a bonding method. More specifically, the present invention relates to a fast-curing adhesive suitable for adhering wood, paper, inorganic materials, etc., and an adhesion method.

[Prior Art] Conventionally, adhesives of this type include polyvinyl alcohols, starches, polyvinyl acetate emulsions, urea resins, rubber resins, Epoquin resins, isocyanate compounds, and the like.

However, with the exception of adhesives made of rubber-based resins, all adhesives have poor initial adhesive strength, and rubber-based resin adhesives also use large amounts of organic solvents, resulting in toxicity and fire hazards, and they also deteriorate over time. It has the disadvantage of being easy. As a countermeasure against this, a fast-curing adhesive consisting of isobutylene-maleimide-maleic anhydride copolymer and glyoxal (Japanese Patent Publication No. 63-1787+), an aqueous solution and/or aqueous emulsion of an acetoacetyl group-containing polymer compound and an aldehyde, Two-component adhesive consisting of polyethyleneimine or hydrazine compound (Japanese Patent Publication No. 1-60190 to 60192)
No.) has been proposed.

[Problems to be Solved by the Invention] However, although the above-mentioned adhesive uses aldehydes, polyethyleneimine, and hydranone compounds as curing agents, and although the initial adhesive strength is improved, it is difficult to penetrate into the porous adherend material. , the yield of the surface portion is insufficient and the initial adhesion strength varies. Furthermore, depending on the application, the initial adhesive strength of the adhesive is not sufficient, and the permanent adhesive strength after drying tends to be insufficient, and there are voices calling for further improvement. Therefore, the object of the present invention is to provide a material that has initial adhesive strength and permanent adhesive strength after drying, without contaminating or aging the adherend, has particularly strong water resistance, has stable adhesive strength, and can be bonded by cold pressing in a short period of time. An object of the present invention is to provide an aqueous adhesive composition and an adhesion method with good workability.

"Means for Solving the Problems" However, in order to achieve the above object, the inventors of the present invention have conducted extensive research1, and as a result, have developed an acetoacetyl group-containing polyvinyl alcohol-based tree M& (hereinafter abbreviated as AA-PVA).
An adhesive consisting of A liquid consisting of an aqueous liquid containing A and B liquid consisting of a polyaminoamide resin having two or more amino groups and amide groups in the molecule, and the above A and B liquids respectively applied to the adherend, and attached. The present invention was completed by discovering an adhesive method for closely bonding coated surfaces together.

The present invention cures in an extremely short time by bringing the above-mentioned liquid A into contact with liquid B, which is a specific curing agent, and exhibits excellent initial adhesion strength. In addition, it has excellent permanent adhesive strength after drying, and the polyamide amine of liquid B has little penetration into the adherend, has excellent adhesion, is stable, exhibits solid adhesive strength, and has low volatility. It has low irritation and oral toxicity, and is advantageous in terms of safety and health. The present invention will be described in detail below.

Of the liquid A used in the present invention, AA-PVA is obtained by reacting polyhinyl alcohol (hereinafter abbreviated as P to A) or a derivative thereof with diketene by a known method. For example, PVA is dispersed in an acetic acid solvent and diketene is added thereto, or PVA is previously dissolved in a solvent such as dimethylformamide or oxane.
This method involves adding diketene to this. In addition, diketene gas or liquid diketene is brought into direct contact with PVA.
A method of obtaining chemically modified PVA may also be adopted. The PVA used in obtaining the AA-PVA is not particularly limited, but preferably has an average degree of polymerization of 200 to 3,500 and an average saponification degree of 30 to 99 mol%. AA-conjugated PV obtained as described above
Among A, those used in the present invention have a degree of acetoacetylation of 0.5 to 20 mol%, which is suitable.

The AA-PVA-containing aqueous solution of the present invention refers to an AA-PVA aqueous solution and an AA-PVA-containing emulsion, and in the case of an aqueous solution, the concentration range is preferably 2 to 50%.

There are no particular limitations on how to prepare an emulsion containing AA-PVA. ■ Emulsion polymerization of monomers using AA-PVA as an emulsifier or protective colloid. ■ Adding a solution or melt of a synthetic resin to AA-PVA. The above three cases include: (1) adding AA-PVA to a synthetic resin emulsion obtained by any method to produce a more stable emulsion; Each case will be specifically explained below.

(2) Method using emulsion polymerization This method is usually suitably carried out when producing a polymer emulsion of a vinyl compound.

In the emulsion polymerization, a conventional emulsion polymerization method can be carried out in which a vinyl compound is added temporarily or continuously in the presence of water, AA-PVA, and a polymerization catalyst, and the mixture is heated and stirred.

The amount of AA-PVA used is 0.1 to 0.1 to the solid content of the polymer.
A weight of 30% by weight, preferably 2-20% by weight, is suitable. If the amount is less than 2% by weight, no sufficient effect will be obtained, and if it is more than 20% by weight, the effect will not increase in proportion to the amount used. The AA
The compound PVA can be added at any time, such as at the beginning, during or after emulsion polymerization, and is usually added at the beginning or during the emulsion polymerization.

Vinyl compounds used in this method include vinyl acetate, vinyl propionate, acrylic ester, methacrylic ester, vinyl chloride, hnylidene chloride, acrylonitrile, methacrylonitrile, styrene, ethylene, propylene, grindyl acrylate, glycol Grindyl group-containing compounds such as methacrylate, grindyl dihinyl ether, and grindyl hinyl ether, N-
Methylol group-containing compounds such as methylol acrylamide and N-methylol methacrylamide, and their alkoxy group-containing derivatives, carboxylic acid amides such as acrylamide and methacrylamide, carboxylic acids such as acrylic acid and methacrylic acid, nohynylambate, and divinyl sacnonate. , triallyl citrate, diallyl fumarate, triallyl citrate, diallyl maleate, vinyl persatate, etc., which are homopolymerized or copolymerized. Among these, vinyl acetate alone or a copolymer mainly composed of vinyl acetate is preferred.

As the emulsion polymerization catalyst, a catalyst used in normal emulsion polymerization is used. Redox catalysts are particularly preferred, and specific examples include hydrogen peroxide, ammonium persulfate, potassium persulfate each alone, sodium metabisulfite, sodium bisulfite, ferrous sulfate, dimethylaniline, formaldehyde zinc sulfoquinlate, or formaldehyde. An example is a combination with sodium sulfoquinolate.

Furthermore, nonionic surfactants and ionic surfactants can also be used in combination with acetoacetylated PVA. Furthermore, other emulsifiers such as PVA, cellulose derivatives (carboxylic methyl cellulose, hydroxyethyl cellulose, methyl cellulose, etc.), polyacrylic acid derivatives, (anhydrous) maleic acid-vinyl ether copolymers, (anhydrous) maleic acid-vinyl acetate copolymers, Vinyl acetate-(meth)allylsulfonic acid (
Saponified copolymers (salts) can also be used in combination as appropriate.

Other various additives and preparation agents used in ordinary emulsion polymerization can also be used as appropriate.

(2) Post-emulsification method This method is preferably carried out when preparing a synthetic resin emulsion that is difficult to produce by emulsion polymerization.

This method is as follows: A: Dissolve AA-PVA in water, drop a solution or molten resin into the solution and stir, or drop an aqueous solution of AA-PVA into the molten resin and stir. .

There is no particular need for heating during emulsification, but if necessary, heating may be performed to about 45 to 85°C. The substance to be emulsified is not particularly limited, and examples include urethane resin, urea-formalin initial condensate, phenol-formaldehyde initial condensate, Alkit resin, polyester resin, ketene dimer, silicone resin, wax, polypropylene, and polyethylene.

The amount of AA-PVA used varies somewhat depending on the resin content of the required emulsion, etc., and is usually selected from the range of 0.1 to 30% by weight, preferably 1 to 25% by weight based on the object to be emulsified. . If necessary, a nonionic activator such as a polyoxine ethylene-alkyl ether type, a polyoquinoethylene-alkyl phenol type, a polyhydric alcohol ester type, or a cationic activator such as a higher alkyl amine salt is appropriately used in combination with the resin. You can also do that.

It is also possible to mix these active agents into the object to be emulsified.

(2) Post-addition method This method is carried out by adding AA-PVA to a synthetic resin emulsion obtained by any method for the purpose of further improving stability or thickening.

Targeted emulsions include styrene/butadiene emulsions, cis-1,4 polyisoprene emulsions, chloroprene emulsions, acrylonitrile/butadiene emulsions, vinylpyridine emulsions, methyl methacrylate/butadiene emulsions, polywemulsions, polyethylene emulsions, Examples include silicone emulsion, polybutene emulsion, and thiol emulsion.

When adding AA-PVA to the emulsion, the PVA
When adding PVA as an aqueous solution, it is sufficient to simply add the aqueous solution to the emulsion at room temperature while stirring, but when adding the PVA powder, add the powder while stirring the emulsion, and add the emulsion to the emulsion while stirring. It is preferable to heat the mixture to 85° C. because uniform mixing can be completed in a short time.

The amount of AA-PVA used is approximately 1 to 40% by weight, preferably 2 to 30% by weight, based on the solid content of the emulsion. When using AA-PVA with a low degree of acetoacetylation, add a large amount; when using AA-PVA with a high degree of acetoacetylation, add a small amount to obtain effects such as thickening. That is, the viscosity increasing effect and the stability improving effect are approximately proportional to the degree of acetoacetylation and the amount added. Therefore, it is desirable to understand these relationships and select the degree of acetoacetylation and the amount added depending on the purpose.)

In this way, the AA-modified PVA aqueous solution and ■, ■, ■ were obtained＼
, and its derivatives, various water-soluble polymers such as starch, or various emulsions and latexes. Furthermore, polyvalent metal salts, isonoanate compounds, and amino resins are used to strengthen adhesion. Coating aids such as plasticizers and high boiling point solvents. Clay, carbonate, talc, calcium silicate. Extender pigments such as kaolin and diatomaceous earth. Colored pigments such as titanium oxide. Preservatives, insect repellents, rust preventives, antifoaming agents, binders, etc. are appropriately mixed and used.

Next, liquid B will be explained. Polyaminoamide resin, which has two or more amino groups and amide groups in its molecule, is a drying oil,
A condensate of dimer acid obtained from fatty acids from semi-drying oil, tall oil, etc. and polyamine, or a condensate and modified product of polycarboxylic acid and polyamine, which contain reactive primary and secondary amino acids in the molecule. It is a polyamide resin having groups.

- Refers to a substance widely used as a curing agent for epochino resin in boat fishing. The polyaminoamide resin used in the present invention is not particularly limited, but has an amine value of 100 to 8.
A suitable viscosity at 0.30°C is 05 to 700 poise. The polyamide amine may be used as it is, or in order to adjust the curing rate, polyamines such as aliphatic polyamines, aromatic polyamines, and alicyclic polyamines, alcohols, and curing accelerators such as phenols, acids, hydroxyamines, and sulfonamides, It is used by appropriately blending a rust preventive agent such as lentin or lanolin, a preservative, a binder, etc., and diluting it with an aqueous solution or a mixed solvent such as a lower alcohol.

The fast-curing water-based adhesive consisting of two liquids A and B obtained by the present invention can be used as a l-wave type in which liquids A and B are mixed in advance, or it is usually used as a two-part type in terms of adhesive stability. used. That is, the adhesion surface of the base material to which liquid A is to be adhered;
For example, if you apply it to the surface of wood, etc., apply it to the surface of the other base material to which you want to adhere, and immediately bring both sides together and press them together, it will be fixed within 10 seconds to 10 minutes at room temperature. l
Since the adhesive can be bonded to a strength of 1, the pressure can be released, and if left as is to cure, a sufficiently high adhesive strength can be obtained.

The coating amount of the adhesive that exhibits excellent initial adhesive strength and permanent adhesive strength is 0.5 to 60 parts, preferably 2 to 30 parts of B liquid per 100 parts by weight (solid content) of A liquid, preferably 2 to 30 parts (polyamino (based on amide resin solid content) is appropriate.

The fast-curing water-based adhesive thus obtained can be used on fibrous materials such as wood, plywood, particle hoard, and hardboard, inorganic materials such as slate boards, silica boards, mortar, and tiles, and plastic materials such as melamine decorative boards, Bakelite, and expanded polystyrene. It can be applied to high-speed adhesion of paper materials such as corrugated paperboard and kraft paper, as well as as a treatment agent for fibers, a binder for non-woven fabrics, and paints.

[Function] The fast-curing water-based adhesive of the present invention causes a curing reaction by applying liquids A and B separately to the surface of the adherend, and then bringing the coated surfaces into contact with each other, with slight compression. Just by applying it, you can achieve strong adhesion in a short time. Therefore, the work is speeded up and labor-saving. Furthermore, compared to conventional fast-curing water-based adhesives, it has a stronger permanent adhesive strength after drying, and because it penetrates less into the adherend, the adhesive strength is always stable, making it extremely advantageous industrially.

[In the example Hereinafter, the present invention will be specifically explained with reference to Examples.

In the examples, "part" or "%" means "1 part by weight" or "% by weight."

Example 1 Solutions A and B shown below were prepared.

Solution A 15% aqueous solution of acetoacetylated polyvinyl alcohol Solution B Tomide #255 (polyamide resin manufactured by Fuji Chemical Industry Co., Ltd.) 20% aqueous solution The normal compressive shear adhesive strength of the fast-curing water-based adhesive consisting of Solutions A and B is shown below. It was measured using the method shown below. The results are summarized in Table 1.

Compressive shear adhesive strength (according to JISK-6852) (normal state) Apply liquid A to one adhesive surface of two pieces of birch wood measuring 25 mm x 30 mm x l Omm at a coating amount of 70 g/m' (solid content). On the other side, 10 ij of liquid B was applied in an amount of 4 m 2 (solid content of polyamide amine resin), and both surfaces were brought into contact and immediately pressed at 5 to 9 r/cm'. Then, the pressure was released after each of the pressing times shown in Table 1, and the compressive shear adhesive strength was measured after curing for 5 minutes and after curing for 72 hours.

(Water Resistance) After the above-mentioned curing, the adhesive test piece was immersed in room temperature water at about 25° C. for 6 hours, and the compressive shear strength was immediately measured.

(Hot Water Resistance) After the above-mentioned curing, the adhesive test piece was immersed in 60° C. hot water for 3 hours and then cooled to room temperature water, and the compressive shear strength was immediately measured.

Example 2 Solutions A and B shown below were prepared.

Solution A: Same as in Example 1, 25 parts of calcium carbonate (White SB Red, manufactured by Shiraishi Chikararunoum Co., Ltd.) is added to a 5% aqueous solution of AA-PVAl - Solution B: 20% Tomide #2500 (polyamide resin, manufactured by Fuji Kasei Kogyo Co., Ltd.) According to Aqueous Solution Example 1, the compressive shear adhesive strength of the fast-curing aqueous adhesive consisting of Liquids A and B shown above was measured. The results are summarized in Table 1.

Example 3 Solutions A and B shown below were prepared.

An emulsion was obtained in the following manner using AA-PVA having an average polymerization degree of 1200, a saponification degree of 96.5 mol%, and an acetoacetylation degree of 4.9 mol%.

In a separable flask equipped with a stirrer, reflux condenser, dropping funnel, and thermometer, water 1501i and the above AA-PVA 1
After 5 parts were charged and heated to completely dissolve, -10 parts of vinyl acetate monomer was added, and the temperature inside the flask was raised to 67°C while stirring. During this time, the inside of the flask was purged with nitrogen gas, and 3 m of 2% potassium persulfate water was added to initiate polymerization.

Initial polymerization was carried out for 60 minutes, and the remaining vinyl acetate monomer 1
10 parts were added dropwise over 3 hours, during which time 12 m (!) of 2% potassium persulfate water was added continuously to charge all the monomers, and then aged at 70°C for 1 hour to obtain an aqueous emulsion.

(Solid content concentration: 45%) Liquid B Same as Example 1. The compressive shear adhesive strength of the fast-curing water-based adhesive made from Liquids A and B shown above was measured according to Example 1. The results are summarized in Table 1.

Example 4 Using the same AA-PVA as in Example 3, an ethylene/vinyl acetate/acrylic acid copolymer emulsion was obtained in the following manner.

8.33% of the above AA-modified PVA was added to the autoclave for polymerization.
300 parts of an aqueous solution was charged, the internal temperature was raised to 65°C, and then ethylene was injected and maintained at 30 kg; 'cm'.
The internal temperature was raised to 75°C, and 10 parts of a 5% aqueous solution of 15 parts of acrylic acid, 140 parts of vinyl acetate, and ammonium persulfate were added.
Emulsion polymerization is carried out by dripping over a period of time, the ethylene pressure is returned to normal pressure, and after further aging for 1 hour, the solid content concentration is 45%.
An aqueous emulsion was obtained.

Liquid B In the same manner as in Example 1, the compressive shear adhesive strength of the fast-curing water-based adhesive consisting of Liquids A and B shown above was measured. The results are summarized in Table 1.

Example 5 Solution A: 100 parts of saponified ethylene-vinyl acetate copolymer (resin content 50%, viscosity 530 cps), polymerization degree 500,
Saponification degree 99 mol%, acetoacetylation degree 6.0 mol%
60 parts of a 20% aqueous solution of AA-PVA was added and mixed to obtain an aqueous emulsion.

Liquid B In the same manner as in Example 1, the compressive shear adhesive strength of the fast-curing water-based adhesive consisting of Liquids A and B shown above was measured. The results are summarized in Table 1.

Control Example 1 An experiment was conducted in accordance with Example 1, except that a 20% glyoxal aqueous solution was used as Solution B. The results are summarized in Table 1.

Control Example 2 An experiment was carried out in accordance with Example 1 except that 15% aciboyl dihydrazide was used as solution B. The results are summarized in Table 1.

Control Example 3 An experiment was carried out in accordance with Example 3, except that polyethyleneimine with a degree of polymerization of 500 was used as liquid B. The results are summarized in Table 1.

Control Example 4 An experiment was conducted in accordance with Example 3 without using Solution B. The results are summarized in Table 1.

[Effects] The fast-curing water-based adhesive of the present invention has extremely excellent initial adhesion, and can obtain extremely high adhesion strength even after being left to stand after being pressed for a short time.

Moreover, it exhibits permanent water-resistant adhesive strength, and the hardening agent hardly penetrates into the adherend and always exhibits adhesive properties, making it an adhesive with high industrial value.

Claims (1)

[Scope of Claims] 1. A fast-curing aqueous solution consisting of a liquid A consisting of an aqueous liquid containing an acetoacetyl group-containing polyvinyl alcohol resin and a liquid B consisting of a polyaminoamide resin having two or more amino groups and amide groups in the molecule. An adhesion method comprising applying adhesive 2, liquid A and liquid B according to claim 1, separately to the surface of an adherend, and then bonding the coated surfaces together.