JPS58196281A - Amino resin adhesive - Google Patents

Abstract

PURPOSE:An amino resin adhesive useful for preparing plywood, particle board, etc. having improved viscosity stability and good solubility, obtained by blending an amino resin adhesive with rice flour or corn flour as an adhesive enhancer, CMC and/or sodium alginate. CONSTITUTION:An amino resin adhesive is blended with (A) preferably 20- 30wt% rice flour or corn flour as an adhesive enhancer and (B) preferably 0.1- 3wt% CMC and/or sodium alginate as a viscosity builder. The particle size of the component A is preferably >=100 meshes. USE:Bonding for common wood, nonwoven fabrics, paper, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an amino resin adhesive having excellent viscosity stability and good solubility.

Conventionally, amine resin adhesives have been prepared by heating and condensing amino compounds such as urea and melamine with aldehydes such as formaldehyde in an aqueous medium in the presence of a catalyst that provides an appropriate pH9. This is required to have a certain viscosity in order to improve temporary adhesive strength and coatability. In order to meet this requirement, if the degree of the condensation reaction is increased, the resulting resin liquid becomes unstable and tends to gel.9 Also, in the case of unmodified resin, there is a drawback that aging of the adhesive part becomes significant. be. As a method for solving these drawbacks, a method has been proposed in which polyvinyl alcohol is added to the condensation reaction system to increase the viscosity. However, modification with polyvinyl alcohol has not always been fully satisfactory in terms of improving the temporary adhesive strength of the adhesive. Therefore, it cannot be applied to the so-called semi-clamp method that has recently been adopted in the manufacture of plywood and the like.

In order to apply K to this type of purpose, it is conceivable to make the degree of polymerization of the polyvinyl alcohol used here extremely high, or to increase the amount of polyvinyl alcohol added to the condensation reaction system. In addition, it is difficult to stop the condensation reaction at a desired condensation rate, and the resulting resin liquid has poor stability and rapidly thickens into a gel.

In addition, as a method of thickening this type of resin adhesive, it is also known to add a thickener such as polyvinyl alcohol or cellulose ether to the resin liquid after the condensation reaction has stopped; Since the compatibility between the agent and the resin liquid is poor, the stability of the system deteriorates, resulting in disadvantages such as phase separation, gelation, and decreased temporary adhesion. Furthermore, it is customary to add wheat flour or rice flour to the resin liquid just before using it as an adhesive to increase its apparent viscosity.
In this case, the compatibility is poor, and the temporary adhesive strength varies greatly depending on the moisture content of the wood used, and if the amount of flour is increased too much, the result is that the normal and water-resistant adhesive strength is not adversely affected.

The present inventors have completed various studies to solve these conventional drawbacks, and as a result, have completed the present invention.

That is, the present invention relates to an amino resin adhesive containing rice flour or corn flour as an adhesion enhancer and a thickener selected from carboxymethyl cellulose and sodium alginate.

According to the present invention, by blending rice flour, corn flour, carboxymethyl cellulose (cMc) and/or sodium alginate into the amino resin adhesive, it is possible to improve the solubility and significantly improve the viscosity stability.

If rice flour or corn flour is simply added to an amino resin adhesive, the adhesive has the disadvantage of poor applicability to veneers due to its low viscosity, and poor temporary adhesion and adhesive strength. In addition, in the present invention, rice flour is used in combination with corn flour, OMO and sodium alginate are added alone to an amine resin adhesive, but the viscosity increases in a short period of time9, and the viscosity decreases during hot pressing, resulting in The disadvantage is that it penetrates into the adhesive and weakens the adhesive. In the present invention, rice flour Maku is used in combination with cornflour.
Although C and sodium alginate are substances known as thickeners, in the present invention, the purpose of the present invention cannot be achieved even if thickeners other than those mentioned above, such as sodium polyacrylate, are used. Examples of amino compounds that are the main components of resin adhesives include urea, thiourea, melamine, pendiguanadenone, acedoguanamide, dicyandiamide, and aniline, and examples of aldehydes include formaldehyde, paraformaldehyde, and aldehyde anhydride. Examples include compounds that decompose to produce formaldehyde, such as acetaldehyde, butyraldehyde, glyoxal, benzaldehyde, or hexamethylenetetramine.

In addition, the rice flour and corn flour according to the present invention are obtained by crushing rice and corn using a crusher such as a roll or pin mill, or by sieving this crushed product and dividing it into appropriate sections. You can also use When the grain size of the rice flour obtained in this manner is set to 70 mesh or less, preferably 100 mesh or less, temporary adhesion can be achieved.

The amount of rice flour and cornflour to be added to the amino resin adhesive is 15 to 35 seconds, preferably 20 to 30 seconds, relative to the amino resin adhesive. Also, the amount of OMO and sodium alginate added is 0.05 to 5, preferably 0.1 to 5, per rice flour and/or corn flour.
The range of 3rd grade is good.

Hardening agents for amino resin adhesives include overt hardening agents represented by acids such as hydrochloric acid, sulfuric acid, oxalic acid, and acetic acid, ammonium salts such as hydrochloric acid, sulfuric acid, nitric acid, and sulfuric acid, and nucleic acids and amino acids. Examples include latent curing agents such as salts with amines such as methyl propatool, and other overbreeding products such as hydrogen peroxide and potassium persulfate.

The amino-based resin adhesive of the present invention has excellent viscosity stability, so even if a thick WK adhesive liquid is prepared during work, it can be used sufficiently, so the work for preparing the adhesive can be significantly reduced. Efficiency is significantly improved.

The amine resin adhesive according to the present invention can be used as an excellent adhesive for manufacturing plywood particle boards, fiberboards, reinforced wood, etc., or for bonding other general woods, nonwoven fabrics, paper, etc., and can also be used in various fields. Widely used as a binder in conventional amino resin adhesives.

Next, the present invention will be described in the ninth example to explain the present invention more specifically, but the present invention is not limited to the following examples.

Example 1 Urea formaldehyde resin (trade name "Resin 210J" manufactured by Futai Shinko Co., Ltd.) 100 weight 11i 1 part, rice flour (100
25 parts by weight (below Metsushi), CM (1! (trade name: "Trogen", manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) α25 heavy construction part, 1 part of water
8 parts by weight and 0.5 parts by weight of ammonium chloride are mixed and stirred for 5 minutes at room temperature to prepare a resin adhesive.

Example 2 Urea formaldehyde side moon "(Resin 210) joof
fi amount part, core placement part lower (100 mesh or less) 25
The overlay part, 0.5 part by weight of sodium alginate, 18 parts by weight of water, and the overlapping part of ammonium chloride 03 are mixed in the same manner as in Example 1 to obtain a resin adhesive.

Example 3 A resin adhesive was prepared in the same manner as in Example 1, except that Resin 641J (trade name, manufactured by Ohshika Shinko Co., Ltd.) was used instead of ψ111 (7) mJ formaldehyde resin (Resin 210).

Comparative Example 1 A resin adhesive was prepared by iM by mixing 100 parts of urea formaldehyde resin (Resin 210), 25 parts by weight of wheat flour, 18 parts by weight of water and 3 parts by weight of ammonium chloride α.

Comparative example 2 Urea formaldehyde resin (Resin 210) 1003F
'1. A resin adhesive is prepared by mixing part 1, 25 parts of rice flour (100 mesh or less), 1 part of water, 18 parts by weight of water, and 0.3 part by weight of ammonium chloride.

Comparative example 6 Urea formaldehyde)-1 resin (Resin 210) 100
Parts by weight, 1 part by weight of CMC (trade name "Celogen"), 1 part by weight of water
A resin adhesive is prepared by mixing 8 parts by weight and 0.5 parts by weight of ammonium chloride.

Comparative Example 4 A resin adhesive is prepared by mixing 100 parts by weight of urea formaldehyde resin (Resin 210), 2 parts by weight of sodium alginate, 18 parts by weight of water, and 0.3 parts by weight of ammonium chloride.

Comparative Example 5 100 parts by weight of urea formaldehyde am<resin 210), 25 parts by weight of rice flour (100 mesh or less), 1125 parts by weight of sodium polyacrylate, 18 parts by weight of water and 0.5 parts by weight of ammonium chloride were mixed. Prepare resin adhesive.

Test Examples The resin adhesives prepared in the above Examples and Comparative Examples were tested for solubility and viscosity change over time. The test results are shown in Table 1.

Solubility Test The solubility of the adhesion enhancer in preparing each of the above Examples and Comparative Examples was investigated.

Viscosity change test over time The resin adhesives prepared in each of the above Examples and Comparative Examples were tested using a BL type rotational viscometer manufactured by Tokyo Keiki Co., Ltd.
The viscosity was measured immediately after AR, 1190 minutes after finishing and 180 minutes after &4 finishing.

Table 1 Example 1 (Rice flour Good 21 21 22 MC Example 2 (''-77 Rawaa, Gi2ddda Good 22 23 23 Comparative example 1 Flour Becomes Mamako 22 27 5
4 Comparative Example 2 Rice Flour Good 344

Claims (1)

[Claims] An amine resin adhesive characterized by containing rice flour or corn flour, carboxymethyl cellulose, and/or sodium alginate as adhesion enhancers.