JPH04277580A - Bonding method - Google Patents

Abstract

PURPOSE:To realize the instantaneous development of the initial adhesive power of an adhesive by simultaneously spraying a specified aqueous emulsion adhesive and a gelling agent for this adhesive to mix them in a sprayed droplet state and applying the mixture to an adherend. CONSTITUTION:A principal component which is composed mainly of an emulsion adhesive having acetoacetyl groups and a gelling agent which comprises an aqueous solution of a hydrazine compound are simultaneously sprayed and mixed in a sprayed droplet state at a weight ratio of the former to the latter of about 1:0.1 to 1:5 and the mixture is applied to an adherend.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive method for instantaneously developing initial adhesive strength using a specific two-component water-dispersed adhesive.

0002

[Prior Art] Conventionally, adhesives mainly using organic solvents as a medium have been used, but due to flammability, toxicity, and other pollution problems, in recent years, one or both of the adherends has been In the case of materials that permeate and absorb water vapor, water-dispersed adhesives such as emulsion-type water-based adhesives have come to be widely used. Emulsion type water-based adhesives are generally
It is an adhesive made of an emulsion of a polymeric substance in water as a medium, mixed with tackifier, fillers, plasticizers, colorants, anti-aging agents, etc., and is non-flammable, has low toxicity, and is safe. It has various advantages such as being hygienic, having a large filling effect due to its low viscosity even though it has a large nonvolatile content, and being dilutable with water. However, compared to conventional organic solvent-based adhesives, emulsion-type water-based adhesives have a major drawback in that the initial adhesive strength is slow to develop and it takes time to develop sufficient adhesive strength. , has become a big problem.

Therefore, various methods have been investigated to quickly develop the initial adhesive strength of the adhesive, such as increasing the solid content of the adhesive to increase its viscosity, or heating the adherend before or after applying the adhesive. Methods have been proposed, such as evaporating the water by evaporating the adhesive, but these methods deteriorate the storage stability and application workability of the adhesive, require separate equipment, and are not very effective. I haven't found anything that satisfies me yet.

[0004]Also, an adhesion method has been considered in which an emulsion-type water-based adhesive and a gelling agent are separately applied to the adherend and bonded together, but the two form separate layers at the adhesive interface and do not mix well. Therefore, there was a drawback that sufficient initial adhesive strength was not developed.

[0005]

[Problems to be Solved by the Invention] The problem to be solved by the present invention is to provide an adhesive method that instantly develops stable initial adhesive strength using a water-dispersed adhesive such as an emulsion-type water-based adhesive. It's about doing.

[0006]

[Means for Solving the Problems] The present invention provides a two-liquid solution consisting of a main component mainly composed of an emulsion type water-based adhesive having an acetoacetyl group, and a gelling agent mainly composed of an aqueous solution of a hydrazine compound. When adhering adherends using a dispersion type adhesive, this is an adhesion method characterized by spraying a base agent and a gelling agent at the same time, mixing them in the form of mist droplets, and applying the mixture to the adherend.

That is, in bonding adherends using an emulsion-type water-based adhesive, the present invention simultaneously sprays the adhesive and a gelling agent containing a substance to gel the adhesive. , provides an adhesion method characterized in that the mixture is mixed in the form of mist droplets and applied to an adherend. Compared to conventional methods, the method of the present invention develops initial adhesive strength extremely quickly, does not require temporary fixing, and improves adhesive workability. It has the advantage of not requiring special equipment. Furthermore, when an emulsion-type water-based adhesive and a gelling agent are applied separately to an adherend, they form separate layers at the adhesive interface and do not mix well, resulting in insufficient initial adhesive strength. However, the method of the present invention According to the method, the adhesive and the gelling agent are well mixed in the air in the form of droplets just before being applied to the adherend, so that extremely excellent initial adhesive strength is developed.

[0008] Thus, in the method of the present invention, the emulsion type water-based adhesive and the gelling agent are each simultaneously sprayed onto the adherend so that the spray areas overlap. The spraying equipment used is not particularly limited, and any equipment may be used as long as the adhesive and gelling agent can be sprayed at the same time and their spraying areas overlap, and either air spray or airless spray may be used. For example, two spray guns adjusted so that their spray areas overlap may be used, or a two-headed spray gun (for example, BINKS MANUFACTURRIN in the US) may be used.
Made by G COMPANY, 69GM PLURAL
COMPONENTSPRAY GUN) can be used. It is also possible to use one spray gun and spray the adhesive and gelling agent simultaneously from its nozzle and air hole, respectively.

The emulsion-type water-based adhesive having an acetoacetyl group used in the present invention is an aqueous solution of a polymer compound having an acetoacetyl group in the molecule, ie, a water-soluble highly water-based adhesive such as polyvinyl alcohol, hydroxyalkylcellulose, starch, etc. Aqueous solutions of acetoacetylated polyvinyl alcohol, acetoacetylated, acetoacetylated starch, etc., which are acetoacetylated molecular compounds, and natural rubber polyvinyl acetate, vinyl acetate copolymer, etc. Polyacrylic acid ester, acrylic acid ester copolymer, ethylene vinyl acetate copolymer, polyolefin, styrene butadiene copolymer, methyl methacrylic acid ester butadiene copolymer, nitrile butadiene copolymer, polychloropyrene, polyisoprene. There are blends of emulsions whose main components are styrene isoprene copolymer, polyvinyl chloride, vinylidene chloride copolymer, polyvinyl alkyl ether, and phenol-formalin reactive mixture. Furthermore, monomers containing an acetoacetyl group, such as acryl acetoacetate, vinyl acetoacetate, 2-acetoacetoxyethyl acrylate, 2-acetoacetoxyethyl methacrylate, 2-acetoacetoxypropyl acrylate, 2-acetoacetoxypropyl methacrylate, etc. , α, β ethylenic monomer,
For example, vinyl esters such as vinyl acetate, saturated aliphatic vinyl esters branched at the α-position, methyl acrylate or methyl methacrylate [hereinafter referred to as methyl (meth)acrylate], ethyl (meth)acrylate, butyl (meth)acrylate , 2-ethylhexyl (
By emulsion copolymerizing with (meth)acrylates such as meth)acrylate and nonyl(meth)acrylate, and monovinyl monomers such as styrene, acrylonitrile, ethylene, and vinyl chloride, polymers with acetoacetyl groups in the molecule are produced. Aqueous emulsions of the compounds are suitable. It also includes an aqueous polymer emulsion obtained by emulsion polymerization using acetoacetylated polyvinyl alcohol as an emulsifier.

[0010] Next, the hydrazine compound for gelling the adhesive includes hydrazine, hydrazine hydrade, inorganic salts and acids of hydrazine such as hydrochloric acid, sulfuric acid, nitric acid, nitrous acid, phosphoric acid, thiocyanic acid, carbonic acid, and oxalic acid. organic salts such as hydrazine, monosubstituted hydrazine such as methyl, ethyl, propyl, butyl, allyl, 1,1-dimethyl, 1,
asymmetric disubstituted products such as 1-diethyl, 4-n-butyl-metal, and 1,2-dimethyl, 1,2-diethyl,
Examples include symmetric disubstituted compounds such as 1,2-diisopropyl. Particularly suitable hydrazine compounds are carbodihydrazide, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide,
These include terephthalic acid dihydrazide, glycolic acid dihydrazide, and polyacrylic acid hydrazine.

The concentration of these aqueous solutions is usually 1 to 50% of the hydrazine compound, with 2 to 25% being effective in terms of performance and cost.

It is preferable to spray the aqueous adhesive of the present invention onto the adherend at a weight ratio of 1:01 to 1:5; if the gelling agent is too small than the above ratio, gelation may occur. The capacity decreases, resulting in insufficient initial strength, and if too much, the adhesion to the adherend decreases.

Note that a synthetic resin emulsion or synthetic rubber latex may be used in combination with the adhesive of the present invention for the purpose of improving adhesion, heat resistance, water resistance, toughness, elasticity, etc. Further, fillers such as calcium carbonate, plasticizers, preservatives, colorants, etc. can be used in combination as appropriate.

[0014]

[Effects of the Invention] According to the method of the present invention, the adhesive and gelling agent are well mixed in the air in the form of mist droplets immediately before being applied to the adherend, resulting in uniform gelation and extremely stable gelation. Initial strength can be obtained.

The two-component water-based adhesive of the present invention can be applied to fibrous materials such as wood, plywood, particle board, and hardboard, inorganic materials such as slate board, silica board, and mortar, plastic materials such as styrofoam, cardboard, It is suitable for high-speed adhesion of porous adherends such as paperboard and kraft paper.

[0016] Examples and comparative examples will be described below, where % and parts indicate weight % and parts by weight, respectively.

[0017]

[Example] Example 1 15% aqueous solution 3 of acetoacetylated polyvinyl alcohol Gosefimer Z-100 (manufactured by Nippon Gosei Kagaku Co., Ltd.)
0 parts and 70 parts of acrylic emulsion Primal N-580 (manufactured by Rohm & Haas) to prepare a water-based adhesive. Further, a 10% aqueous solution of adipic acid dihydrazide was used as a gelling agent.

Example 2 Acetoacetylated modified acrylic emulsion RA-10
00 (manufactured by Aica Kogyo Co., Ltd.) was used as the water-based adhesive. Moreover, the gelling agent of Example 1 was used as a gelling agent.

[0019]

[Comparative Example] Comparative Example 1 The water-based adhesive of Example 1 was used as a water-based adhesive. No gelling agent.

Comparative Example 2 Acrylic emulsion Primal N-580 was used as a water-based adhesive. A 10% adipic acid hydrazide aqueous solution was used as a gelling agent.

Comparative Example 3 Same as Example (water-based adhesive/gelling agent) except that Example 1
~2, Comparative Examples 1 and 2 were the main adhesion method (air mixing method), and Comparative Example 3 was separate application to the adherend.

The outline of the test method is as follows. The adhesion methods of Examples 1 and 2 and Comparative Examples 1 and 2 were as follows: Adherent: melamine alkyd coated steel plate x urethane foam. Application: Spray on the steel plate side at the same time to mix in the air. Water-based adhesive: 150g/m2 Gelling agent: 25g/m2 Lamination: Lamination immediately after application. Curing...1 minute/room temperature. The adhesion method of Comparative Example 3 was as follows: Adherent: Same as above. Application: Water-based adhesive on the steel plate side. Separately apply gelling agent to urethane foam. Water-based adhesive: 150g/m2 Gelling agent: 25g/m2 Lamination: Lamination immediately after application. Curing...1 minute/room temperature.

The measuring method is as follows. After curing,
Hold the adhesive horizontally with the urethane side facing down, apply a downward load of 100 g to one end of the urethane foam, and
Measure the time until 0 mm peels off. (90 degree peel retention force) The measurement width of the adherend is 25 mm, and the measurement temperature is 25 mm.
℃.

The measurement results are shown in Table 1.

[0025]

[Table 1]

Claims (1)

[Claims] [Claim 1] A two-component water-dispersed adhesive consisting of a main component mainly composed of an emulsion-type water-based adhesive having an acetoacetyl group and a gelling agent mainly composed of an aqueous solution of a hydrazine compound. An adhesion method characterized in that when adhering an adherend, a base agent and a gelling agent are each sprayed simultaneously, mixed in the form of mist droplets, and applied to the adherend.