JPH05179221A - Adhesive used for bonding nylon fiber to woody material - Google Patents

Abstract

PURPOSE:To obtain the subject adhesive improved in bonding operating efficiency by mixing a specific ethylene-vinyl acetate copolymer resin emulsion with a diphenylmethane diisocyanate-containing liquid. CONSTITUTION:The objective adhesive is obtained by mixing (A) 100 pts.wt. ethylene-vinyl acetate copolymer resin emulsion having -10 to -20 deg.C glass transition point, 25-30% ethylene content, 70-75% vinyl acetate content, >=45% solid content and <=65% emulsion content with (B) 3-30 pts.wt. cross-linking agent consisting essentially of diphenylmethane diisocyanate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive agent used for adhering a wood material with a nylon fiber or a material containing nylon fiber as a main material, and its adhesive strength is determined by JAS. The present invention relates to an adhesive having an adhesive strength that sufficiently passes a peeling test.

[0002]

2. Description of the Related Art Conventionally, an adhesive prepared by blending an isocyanate compound with an aqueous emulsion is disclosed in Japanese Patent Publication No.
1-305576, 57-22959, 57-161.
49, all were useful as an adhesive for wood. Further, in the adhesion of the wood material and the nylon fiber material, an ethylene-vinyl acetate copolymer resin emulsion as an adhesive, for example, methyl methacrylate-methyl acrylate-methacrylic acid, methyl methacrylate-ethyl acrylate-methacrylic acid, methyl acrylate-methacrylic acid. It is common to employ an acrylate-based copolymer resin such as, or a polyester-based copolymer resin. When adopting such an adhesive, the adhesive work is usually performed at a temperature of 120 to 160 ° C. for 4 to
It was necessary to continuously hold the press of the adherend for 6 hours.

The adhesive strength of the adhesive obtained by such a method is determined by the Japanese Agricultural Standards (Ministry of Agriculture, Forestry and Fisheries Notification No. 18).
No. 60) does not meet the acceptance criteria of the ordinary plywood dip test.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to an adhesive used for adhering a nylon fiber and a wood material, and is a long-time press under heating which is indispensable in the above-mentioned conventional adhesive adhering work. It is an object of the present invention to eliminate the need for a complicated bonding work such as the above and to significantly improve the bonding strength obtained.

[0005]

Means for Solving the Problems The inventors of the present invention have made extensive studies as to how to solve the above-mentioned problems. The present invention has been achieved by finding that the adhesive strength can be significantly improved by mixing

That is, the present invention has a glass transition point of -10.
An adhesive used for adhering a nylon fiber and a wood material, which is obtained by mixing an ethylene-vinyl acetate copolymer resin emulsion at a temperature of not higher than 0 ° C and a diphenylmethane / diisocyanate-containing liquid.

In the present invention, the glass transition point is -10.
C. or less, -20.degree. C. or more ethylene-vinyl acetate copolymer emulsion, that is, in an emulsion having a solid content of 45% or more and 65% or less, the ethylene content in the solid content is 25% or more, 30% or less, the vinyl acetate content is 70% or more, In a two-component adhesive consisting of a main component of 75% or less ethylene-vinyl acetate copolymer emulsion, and a cross-linking agent containing diphenylmethane diisocyanate as a main component, the mixing ratio of the main component and the cross-linking agent is 100 parts by weight of the main component. It is preferable that the adhesive is 3 parts by weight or more and 30 parts by weight or less.

The present invention will be described in more detail. Among the ethylene-vinyl acetate copolymer resin emulsions used as the main component, those having a glass transition point (hereinafter abbreviated as Tg) of -10 ° C. or less are particularly preferred. Good, especially -1
Those having a Tg in the range of 3 to -20 ° C are desirable. As a material that is generally available, Sumika Chemical Co., Ltd., trade name Sumika Flex 401, Denki Kagaku Kogyo Denka EVA Tex 56 and the like are preferable.

When the Tg of the above-mentioned ethylene-vinyl acetate copolymer resin is -10 ° C or higher, the adhesive state with nylon or a material containing nylon as a main material becomes an excessively hard adhesive state, and the peeling force is increased. Too little absorption and dispersion is not obtained, and a preferable adhesion state cannot be obtained. On the other hand, when Tg is lower than -20 ° C, a sufficient fixed state cannot be obtained, which is not preferable.

The solid content concentration of the ethylene-vinyl acetate copolymer emulsion is usually about 45 to 65% by weight, preferably 50 to 60% by weight.

MDI, which is mentioned as a main component constituting the adhesive of the present invention, acts as a crosslinking agent, and may be used in combination with a plasticizer if desired. In this case, the amount of the plasticizer used is preferably 25% by weight or less and more preferably 13% by weight or less based on the weight of MDI. As the plasticizer used for this purpose, dibutyl phthalate, dioctyl phthalate, toluene and xylene are suitable.

The MDI-containing solution containing the above MDI, and optionally a plasticizer, is usually used as an organic solvent solution having a concentration of 75 to 100% by weight, preferably 87 to 100% by weight.

The adhesive composition constituting the adhesive of the present invention may contain surfactants, protective colloids and other additives which are usually used in order to maintain a suitable emulsion state. ..

As the types of nylon fibers and wood materials to which the adhesive according to the present invention is applied, nylon fibers or wood materials can be applied to any object as long as the materials are mainly nylon fibers or wood materials.

In application to these objects, the ethylene-vinyl acetate copolymer resin emulsion and the MDI-containing liquid are mixed prior to use, and usually applied as a paste liquid to one or both adherends. However, it is possible to obtain a high degree of adhesion by maintaining the adhesion conditions that are easier than the adhesion conditions required for the above-described conventional adhesive bonding operation.

That is, usually, 50 to 300 g / m ² ,
The coating amount is preferably 100 to 200 g / m ^{2 by} a conventional coating method, and is usually 3 to 20 kg / m ^{2 in} the temperature range of 0 to 60 ° C., preferably 5 to 15 k.
It is preferable to press with a force of about g / m ² and maintain the required settling time if necessary.

[0017]

EXAMPLES The present invention will be described in more detail with reference to the following examples.
All parts in the description mean parts by weight.

The test method in the examples was according to the following method.

Two-kind immersion test: Four test pieces each having a 75 mm square are prepared from each sample. 70 test pieces
After soaking in warm water of ℃ ± 3 ℃ for 2 hours, 60 ℃ ± 3
Dry for 3 hours at a temperature of ° C. The test result is judged to be acceptable when the length of the non-stripped portion in the same adhesive layer of the same test piece is 50 mm or more on each measuring surface. Example 1 An adhesive having Tg-18 ° C (Sumitomo Chemical Co., Ltd., Sumikaflex S401) ethylene-vinyl acetate copolymer resin emulsion (solid content concentration 55% by weight) as a main component and MDI as a crosslinking agent, Cross-linking agent 1 to 100 parts of main agent
5 parts (87.5 wt% concentration of MDI dibutyl phthalate solution) were mixed and used as a paste solution. The adherends were nylon fibers and mackerel lumber.

150 g of the above-mentioned glue solution on a mackerel board
After applying at a rate of m ² , a 400 g / m ² woven fabric in which nylon fibers of 15 denier were raised in a pile shape were laminated and pressed at a rate of 10 Kg / cm ² . The pressing time was 60 minutes, and the pressing operation was performed in an atmosphere of 25 ° C.
Then, after being left standing and cured in an environment of 25 ° C. for 3 days, a dip-and-peel test of type II of ordinary plywood defined in the Japanese Agriculture and Forestry Standard (Ministry of Agriculture, Forestry and Fisheries Notification No. 1860) was conducted. That is, a 75 mm square test piece was prepared from the above-described adhesive piece composed of the mackerel pulling board and nylon fiber, immersed in warm water of 70 ° C. for 2 hours, and then dried at a temperature of 60 ° C. for 3 hours.

After that, the presence or absence of peeling was confirmed on each side of the test piece, and no peeling was found.

The acceptance criterion of the main test according to the same standard is that the length of the part where the peeling does not occur in the same adhesive layer of the test piece is 50 mm or more on each side, and the test is used for the main test. The tested test piece was judged to have passed. Example 2 The same ethylene-vinyl acetate copolymer emulsion as in Example 1 having a Tg of -18 ° C was used as the main component, and a crosslinking agent consisting of 80% by weight of MDI and 20% by weight of dibutyl phthalate was used. The nylon fiber and the spruce pine lumber were adhered.

The mixing ratio of the main agent and the crosslinking agent is 100 parts to 10 parts.
As a part, a well-mixed paste solution was applied to a spruce pine wood board at a rate of 100 g / m ² . After that, nylon fibers were stuck together and pressed at a pressure of 8 Kg / cm ^{2 in} an atmosphere of 20 ° C. The pressing time was 45 minutes. Then, after standing and curing in an atmosphere of 20 ° C. for 4 days, the same type II immersion peeling test as in Example 1 was performed.

After the test, no peeling was observed. Comparative Example 1 The same Tg as in Example 1 was obtained without adding MDI.
An ethylene-vinyl acetate copolymer resin emulsion having a temperature of 18 ° C. was used to bond the nylon fiber and the mackerel lumber board.

An ethylene-vinyl acetate copolymer resin emulsion was applied to a mackerel sawing board at a rate of 150 g / m ² , and then nylon fibers similar to those used in Example 1 were laminated,
It pressed for 4 hours using the press maintained at 120 degreeC. The pressure was 10 Kg / cm ² . Then, when the same type II dipping test as in Example 1 was performed, all the test pieces were stripped and the nylon fibers fell off the mackerel sawing plate during dipping in hot water at 70 ° C. Example 3 Tg was -1 so that Tg was -12 ° C.
The ethylene-vinyl acrylate copolymer emulsion having a temperature of 8 ° C. and 0 ° C. was mixed at a ratio of 1: 3 as a main agent, and MD was used.
Adhesion using I as a crosslinking agent was performed in the same manner as in Example 1. Further, the same type II immersion test as in Example 1 was conducted. After the test, the length of the part where peeling does not occur is 50 mm or more on each side, and J
Passed the AS second immersion test. The position of the adhesive layer of the test piece is shown in FIG.

[0026]

[Table 1] Comparative Example 2 Tg was −18 so that Tg was −9 ° C.
Mixing ethylene-vinyl acrylate copolymer emulsion having a temperature of 0 ° C. and 0 ° C. at a ratio of 1: 1 was used as a main component, and MDI was used.
Adhesion similar to that in Example 1 was performed using an adhesive having a cross-linking agent. Further, the same type II immersion test as in Example 1 was conducted. After the test, when the length of the portion where peeling did not occur was measured, peeling exceeding 25 mm was observed on one side. Therefore, the adhesion test piece used for the test was judged to have failed the JAS type II immersion test.

[0027]

[Table 2]

[0028]

The adhesive of the present invention is used as a cross-linking agent in MDI.
Since it is possible to carry out the bonding operation at a lower temperature and pressure than conventional adhesives of this type, it is extremely useful as an adhesive between nylon fibers and wood materials or as an adhesive for the material that is the main material of them. It is useful.

[0029]

[Brief description of drawings]

[0030]

FIG. 1 is a diagram showing the position of a test piece in a dip test of ordinary plywood.

Claims (2)

[Claims] 1. An adhesive used for adhering a nylon fiber and a wood material, which is obtained by mixing an ethylene-vinyl acetate copolymer resin emulsion having a glass transition point of -10 ° C. or less and a diphenylmethane / diisocyanate-containing liquid. 2. A glass transition point of −10 ° C. or lower, −20 ° C.
An ethylene-vinyl acetate copolymer emulsion showing the above,
That is, in an emulsion having a solid content of 45% or more and 65% or less, the amount of ethylene in the solid content is 25% or more and 30% or less,
The ethylene-vinyl acetate copolymer emulsion having a vinyl acetate content of 70% or more and 75% or less is used as a main component, and the mixing ratio of the main component and the cross-linking agent in the two-component adhesive consisting of the cross-linking agent containing diphenylmethane / diisocyanate as the main component is The adhesive according to claim 1, wherein the amount of the crosslinking agent is 3 parts by weight or more and 30 parts by weight or less based on 100 parts by weight of the main agent.