JPS587467A - Adhesive composition - Google Patents

Abstract

PURPOSE:A formaldehyde-free adhesive composition that is composed of a latex of diene copolymer containing carboxyls, an epoxy resin and diethylene ureas in a specific proportion, thus showing high adhesion at ordinary states and high water resistance. CONSTITUTION:(A) A latex of diene copolymer containing carboxyl groups, such as carboxyl-modified styrene-butadiene copolymer latex, (B) an epoxy resin, preferably having 2 or more epoxy groups in one molecule and a molecular weight of 300-400, and (C) a diethyleneurea of the formula (R is -CnH2n-; n is 4-15) such as tolylene-bis-1,4-N,N'-diethyleneurea) are mixed so that the weight ratio of A to B is 99/1-50/50, preferably 98/2-80/20, B/C is 30/1-1/3, preferably 10/1-1/1 on the solid basis to give the objective composition. USE:Adhesive for laminating and wood works.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a non-formalin adhesive composition having excellent normal adhesive strength and water-resistant adhesive strength.

Traditionally, diene copolymer latex adhesives have been used in many applications due to their flexibility, rubber elasticity, and good cold resistance, which are not found in other adhesives. It is not possible to obtain strong adhesive force like that of adhesives, and the adhesive force is not fully satisfactory. In order to compensate for this drawback, it is known to improve the diene copolymer latex by mixing it with a resin containing an epoxy group (Japanese Patent Publication No. 14096/1986, etc.), but the water-resistant adhesive strength is not necessarily sufficient. It wasn't.

Although it is effective to add a methylolmelamine water-resistant agent to improve water-resistant adhesive strength, it requires a heat treatment temperature of 130° C. or higher during bonding and also has the disadvantage of generating formalin.

As a result of intensive studies to solve these problems, the inventors of the present invention were able to obtain an adhesive composition that is a latex/epoxy resin mixed system, has excellent normal adhesive strength and water-resistant adhesive strength, and does not generate formalin. They were successful and completed the present invention.

That is, in the present invention, the mixing ratio of diene copolymer latex containing a carboxyl group and resin containing an epoxy group is 99:1 to 50:50 in parts by weight (solid content), and the epoxy group is Containing resin and general formula % formula % (However, R is -CnH2n- or -CnH2n-2t
Provided is an adhesive composition with excellent water resistance, which is blended with a diethylene urea compound represented by (n = an integer of 4 to 15) in a mixing ratio of 30 = 1 to 1:3 in parts by weight (solid content). It is.

The carboxyl group-containing diene copolymer latex used in the present invention is prepared by adding a carboxyl group-containing polymerizable monomer, a conjugated diene monomer, and optionally an ethylenic monomer copolymerizable with these in a conventional manner. It can be obtained by emulsion polymerization. Examples of the polymerizable monomer having a carboxyl group include acrylic acid, methacrylic acid, itaconic acid, fumaric acid, and maleic acid. Examples of the conjugated diene monomer include butadiene and isoprene, with butadiene being particularly preferred.

Ethylene monomers include styrene, α-methylstyrene, halostyrene, methyl methacrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride, and vinylpyridine. Among them, styrene, methyl methacrylate, etc. are particularly preferred.

The composition of this copolymer is usually 0.5 to 10% by weight of carboxyl group-containing monomer and 0 to 40% by weight of ethylenic monomer.
, the remainder consists of conjugated diene monomers. This copolymer is
Usually, the molecular weight is approximately the same as that of ordinary diene-based synthetic rubber, and it may be partially crosslinked.

The epoxy group-containing resin used in the present invention preferably has two or more epoxy groups per molecule, regardless of whether it is water-soluble or water-insoluble, but its molecular weight is 300.
~400 is preferred.

Such epoxy base-containing resins include: (1) glycidyl ethers of polynuclear phenols, such as glycidyl ethers of bisphenol A (Epicote 8 manufactured by Shell Oil Co., Ltd.);
28 etc.) □ ■ Glycidyl ether of alcohol,
For example, glycidyl ether of dipropylene glycol (e.g., Evicron 705 manufactured by Dainippon Ink), glycidyl ether of glycerin (Denacol EX3 manufactured by Nagase Sangyo, etc.).
13) ■ Glycidyl esters of carboxylic acids, such as glycidyl esters of phthalic acid (Epicote 190 manufactured by Shell Petroleum)
etc.) ■ Bisphenol A and alkylene oxide derivatives,
For example, diglycidyl ether of bisphenol A-glopyrene oxy, side 2 mole adduct (Epolite 3002 manufactured by Kyoeisha Yushi Kagaku, etc.) ■ Alicyclic epoxy resin, such as hydrogenated bisphenol A
Diglycidyl ether (Kyoeisha Yushi Kagaku Evolite 4
000, etc.).

The diethylene urea compound used in the present invention is represented by the general formula (%), and is, for example, tolylene-bis-1,
4-N,N-diethyleneurea, diphenylmethane-bis-4,,4'-N, N'-diethyleneurea, hexane-bis-1,6-N.

N/, > ethylene urea, butane-bis-1゜4-N
, N'-diethyleneurea, and the like.

In the present invention, the mixing ratio of the diene copolymer latex having a carboxyl group and the resin containing an epoxy group is 99=1 to 50:50 in weight parts (solid content), preferably 98:2 to 80:20. be. Mixing ratio is 99:
When the ratio is less than 1, the normal adhesive strength decreases, while when it exceeds 50:50, the blend stability decreases.

In the present invention, the mixing ratio of Jugetsukou containing an epoxy group and diethylene urea compound is 30 parts by weight (solid content).
:1 to 1:3, preferably 10:1 to 1:1. If the mixing ratio is less than 30 parts, the water-resistant adhesive strength will decrease, and 1:3.
If it exceeds this amount, the stability of the formulation will decrease.

In addition to the above-mentioned ingredients, this adhesive contains fillers such as wheat flour, rice flour, wood flour, blood powder, calcium carbonate, calcium chloride, etc. that are commonly used in the technical field, methyl cellulose, Cal-oxymethyl cellulose, hydroxyethyl cellulose, polyester acrylic acid.

Thickeners such as soda, quaternary ammonium salts, amines, acid anhydrides, epoxy resin curing agents, and other auxiliary agents may be used in combination as appropriate.

The preparation time of this adhesive is based on the copolymer latex containing carboxyl groups, the resin containing epoxy groups, and diethyl 2
When urea compounds are mixed, the curing time is determined by the curing time at room temperature.

Although this adhesive can be cured at room temperature, it is generally preferable to heat it after adhesion in order to increase the normal adhesive strength and water-resistant adhesive strength. The heating temperature varies depending on the type of adherend, but is usually 80°C.
Performed at ~120°C.

This adhesive can be used as an adhesive for wood, paper, fibers, plastics, metals, etc., but especially for wood-to-wood, wood-to-other adherends (e.g., paper, textiles, plastics such as PVC, aluminum). Its performance is particularly evident when bonding other inorganic materials such as metals, metals, asbestos slate, and plasterboard. That is, it is suitable as an adhesive for plywood and woodworking.

The invention will be explained below based on examples.

In addition, in the following, "department" means "unless otherwise specified".
Parts by weight (solid content).

[Adhesive evaluation method]

The obtained adhesive was applied to an adherend by the method shown below to prepare a test piece for measuring adhesive strength.

The adherend has a thickness of 1.61L with a moisture content of 11 to 13%.
Using a lauan veneer of II, the adhesive is applied onto the lauan veneer at a rate of 20 jib/2 by using a roll coater, and the same lauan veneer is bonded thereon. Furthermore, the same amount of adhesive was similarly applied thereon, and the same lauan veneer was laminated to create a total of three plywood sheets.

10 Kp/cd (for plywood) of the obtained plywood
x 5 minutes at room temperature, then further heated to 120℃ for 10Ky/d
Heat pressure was applied for 3 minutes (on plywood).

After curing at room temperature for 20 hours, "Japanese Agricultural and Forestry Standards for General-purpose Boards"
The test piece was cut to the dimensions specified in 1 and used as a sample test piece.

The tests were conducted according to the "Japanese Agricultural and Forestry Standards for General Compliant Boards": (1) Normal adhesion test, (2) Class 1 immersion peel test (boiled water), and (2) Class 2 immersion peel test (70°C hot water).

The testing machine used was a plywood tensile testing machine manufactured by Toyo Shikenki Co., Ltd., and all tests were conducted at a peeling rate of 501 LII/min.

Example 1 Carboxy-modified styrene-butadiene co-polymer latex 95 parts (Japan Synthetic Rubber Co., Ltd. JSRO697) Epoxy resin 5 (Nagase Sangyo Co., Ltd. Denacol EX-313) Diphenylmethane-Beiko-4,4'-N,N'-diethylene urea
5 (FS-50 manufactured by Kaisei Chemical Co., Ltd.) Calcium carbonate 100 (Super S manufactured by Maruo Calcium Co., Ltd.) Thickener 1 (Aron A-20L manufactured by Toagosei Co., Ltd., 17.5% aqueous solution) With the above formulation, follow the recipe from the top Approximately 1 in a container with a stirrer
The adhesive composition was prepared by adding sequentially over a period of minutes. The solid content concentration of the product is 62.7%, and the viscosity is 2500CPS (
BM viscometer 6Orpm.

The rotor was Nα4).

Example 2 Carboxy-modified acrylonitrile-butadiene copolymer latex (Crossrene NA-13, manufactured by Takeda Pharmaceutical Co., Ltd.) was used as the diene copolymer latex.
An adhesive composition was produced in the same manner as in Example 1.

Example 3 As an epoxy resin (Kyoeisha Yushi Kagaku Epolite 30
An adhesive composition was produced in the same manner as in Example 1, except that 02) was used.

Comparative Example 1 An adhesive composition was produced in Example 1 except that the carboxy-modified styrene-butadiene latex JSR0697 was changed to 99.5 parts and the epoxy resin Bunacol EX-313 was changed to 0.5 parts.

Comparative Example 2 An adhesive composition was produced by changing the amount of diethylene urea compound F8-50 from 5 parts to 0.1 part in Example 1.

Table 1 shows the evaluation results of Examples 1 to 3 and Comparative Examples 1 and 2.

Examples 1 to 3 all exhibited excellent normal adhesive strength and water-resistant adhesive strength. Comparative Examples 1 and 2 are examples in which the epoxy resin and diethylene urea compound are insufficient, respectively, and both have low normal adhesive strength and water-resistant adhesive strength, and the wood breakage rate when immersed in water is zero.

Examples 4 to 9 and Comparative Examples 3 to 7 Adhesives were prepared according to the formulations shown in Table 2 according to Example 1, and tested for normal adhesive strength, type 1 and type 2 immersion peeling, The results are shown in Table 2.

Examples 4 to 9 all showed excellent normal adhesive strength and water-resistant adhesive strength. In Comparative Example 4, the amount of epoxy resin blended was too large relative to the amount of latex, and the blend became unstable and could not be used as an adhesive. Comparative examples 6 and 7
is an example in which an amine compound known as an epoxy resin curing agent was used instead of a diethylene urea compound, but the wood breakage rate when immersed in water was extremely small at 0 to 10%.

Claims (1)

[Claims] (1) The mixture ratio of diene copolymer latex containing carboxyl groups and resin containing epoxy groups is 99:1 to 50:50 in parts by weight (solid content), and contains epoxy groups. Resin and general formula (where R is -CnH2n- or -CnH2n 2
1n = an integer of 4 to 15) An adhesive composition with excellent water resistance, which is blended in a mixing ratio of 30=1 to 1:3 in parts by weight (solid content) with a diethylene urea compound.