JPH0586158A - Resin composition - Google Patents

Abstract

PURPOSE:To prepare a resin compsn. useful as a putty which prevents not only volume shrinkage due to grain depression after the application to a plywood but also twist or warpage of the plywood by compounding a specific water-base urethane resin with a blowing agent. CONSTITUTION:A water-base carboxylated urethane resin (e.g. Olester UD 500, a product of Mitsui Toatsu Chemicals, Inc.) is compounded with a blowing agent (e.g. NazC03).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition of putty agent for repairing small irregularities on the surface of plywood to a uniform surface. More specifically, the putty agent for improving the fluidity of the resin composition of the putty agent, the coating suitability, the polishing property after applying the putty agent, and the bubble-containing coating film to obtain a smooth surface without volume shrinkage. It relates to a resin composition.

[0002]

2. Description of the Related Art Conventional wood-based resin compositions are classified into solvent-based and water-based compositions. The former is characterized by quick-drying but contains an organic solvent or is used by an operator. There are inconveniences to the environment and health of
In addition, there is a risk of fire hazard during construction. The latter has no inconvenience to the health of the worker and no risk of fire, but the drying property after application is slow and there is a problem in workability.

Furthermore, since a dent caused by the volume shrinkage of the resin, which is usually called "eye stitch", appears after both of them are applied, a resin composition containing a two-pack type urethane resin or a foaming agent has been put on the market. . These meet the needs of a resin having excellent surface smoothness, which does not have a "eye graze", in order to cope with raw wood which is a raw material for plywood and particle board, which have become lower in recent years. At present, it is possible to apply the bubble-containing resin by using a general-purpose device for painting, and then dry and apply the resin at around 100 ° C.

However, this method requires a device for mixing the two liquids, which causes a problem that the work is complicated and the maintenance is troublesome. In addition, wood-based materials such as plywood that are exposed to high temperatures around 100 ° C are "torsion"
In many cases, the value as a product is impaired due to the occurrence of "warp" or "warp". Furthermore, the addition of polyisocyanate shows a foaming effect even at room temperature, but it takes a long time in actual use, it is not economical for industrial use, and the coating itself does not cure. It is sufficient, and there are technical defects such as "clogging" of the paper during sanding in the subsequent process, and its improvement is required.

[0005]

In order to solve these problems, the present inventors have obtained a smooth surface which is foamed and hardened at a low temperature and has no "twist", "warp" and "blurring". The present invention has been completed by finding a low cost putty resin composition for wood, which has good workability and productivity. That is, the present invention relates to a resin composition comprising an aqueous urethane resin having a carboxyl group and a foaming agent.

The present invention will be described in detail below. The aqueous urethane resin having a carboxyl group used in the present invention is manufactured as follows. First, diisocyanates and glycols or polyhydroxycarboxylic acids are reacted at 50 to 100 ° C. in the presence or absence of a solvent to prepare a prepolymer having an isocyanate group.

Next, the prepolymer having an isocyanate group is neutralized with a neutralizing agent, the prepolymer is added to deionized water, and the chain is extended by a chain extender and made aqueous to obtain an aqueous urethane resin.

The diisocyanates used in the present invention include, for example, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 2,
4,4-trimethylhexamethylene diisocyanate,
Aliphatic isocyanates such as 2,8-diisocyanate methyl caproate, 3-isocyanate methyl-3,
5,5-trimethylcyclohexyl isocyanate, dicyclohexylmethane-4,4'-diisocyanate,
Methylcyclohexyl-2,4-diisocyanate,
Alicyclic diisocyanates such as 2,5 and / or 2,6-diisocyanate methylbicyclo [2,2,1] heptane, toluylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthene diisocyanate, diphenylmethylmethane diisocyanate, tetraalkyl Diphenylmethane diisocyanate, 4,4 '
From the group of aromatic diisocyanates such as dibenzyl diisocyanate and 1,3-phenylene diisocyanate, the above chlorinated diisocyanates, brominated diisocyanates, or polyisocyanate compounds which are adducts of these diisocyanates and water Chosen 1
One kind or a mixture of two or more kinds is used.

Examples of glycols include diethylene glycol, butanediol, hexanediol, neopentyl glycol, bisphenol A, cyclohexanedimethanol, trimethylolpropane, glycerin, pentaerythritol, polyethylene glycol, polypropylene glycol, polycarbonate glycol, polyester. One or a mixture of two or more selected from the group of polyol, polycaprolactone, polytetramethylene ether glycol, polythioether glycol, polyacetal polyol, furandimethanol and the like can be mentioned. Furthermore, as the polyhydroxycarboxylic acid, 2,2-dimethylolpropionic acid is preferable.

As the solvent used for producing the aqueous urethane resin, methyl ethyl ketone, methyl isobutyl ketone, isobutyl acetate, butyl acetate, acetone, dimethylformamide, N-methyl-2-pyrrolidone, diethylene glycol dimethyl ether and the like are preferable.

The present invention comprises a step of obtaining an aqueous urethane resin by neutralizing a prepolymer having an isocyanate group with a neutralizing agent, adding the prepolymer to deionized water, and subjecting the prepolymer to chain extension with a chain extender and waterification. Then, a chain extender may be used before adding the prepolymer to deionized water,
It is also possible to add a chain extender to deionized water.

The chain extender used here is preferably water or polyamines, and examples of the polyamines include ethylenediamine, diethylenetriamine, triethylenetetramine, propylenediamine, butylenediamine, hexamethylenediamine, cyclohexylenediamine, piperazine, 2-methylpiperazine, phenylenediamine, tolylenediamine, xylenediamine, α,
α'-methylenebis (2-chloroaniline), 3,3 '
-Dichloro-α, α'-biphenyldiamine, 2,6-
Diaminopyridine, α, α′-diaminodiphenylmethane, m-xylenediamine, isophoronediamine, N-
Methyl-3,3'-diaminopropylamine, 2,5 and / or 2,6-diaminomethylbicyclo [2,2,2]
1] An adduct of heptane or diethylenetriamine and an acrylate, or a hydrolysis product thereof, and the like.

Any known neutralizing agent may be used, but particularly preferred examples thereof include basic organic substances such as dimethylethanolamine, diethylethanolamine and triethylamine.

A resin composition of a putty agent for repairing small irregularities on the surface of plywood to a uniform surface is obtained based on the aqueous urethane resin thus obtained. As the foaming agent used in the resin composition, carbonate compounds such as sodium carbonate, sodium hydrogen carbonate, calcium carbonate, magnesium carbonate, ammonium carbonate, ammonium bicarbonate and ammonium salts such as ammonium chloride, ammonium sulfate and ammonium nitrate are used. .

The amount of the foaming agent added is based on the resin composition.
0.5 to 30% by weight (hereinafter, unless otherwise specified, the weight% is
It is preferably added simply as "%". Addition amount is 0.5
If it is less than%, sufficient results cannot be obtained as a foaming agent. Further, if it exceeds 30%, uniform foaming cannot be obtained, which is not preferable and is economically disadvantageous.

It is more preferable to add a foaming aid in addition to the foaming agent. Examples of the foaming aid used include organic tin compounds. For example, carboxylate salts such as tin (II) acetate, tin (II) octoate, tin (II) ethylhexoate, tin (II) laurate,
Dialkyltin salts such as dibutyltin acetate, dibutyltin laurate, dibutyltin maleate and dioctyltin diacetate are used.

The addition amount of the foaming aid is usually preferably 0.1 to 1.0% with respect to the resin composition. Further, tertiary aliphatic amines are also commonly used,
For example, triethylenediamine, N-ethylmorpholine,
N, N, N-tetramethyl-1,3-butanediamine,
Compounds such as bis-2- (N, N-dimethylamino) ethyl ether, diethylenetriamine, oxybis (N, N-diethanolamine) are used. The amount of the compound added is usually 0.1 to 0.6 with respect to the resin composition.
%, But 0.2 to 0.4% is preferable. The foaming agent and the foaming auxiliary agent are selected from the above-mentioned one and two.
More than one species may be used alone or as a mixture.

Foam stabilizers are often used for uniform and smooth foaming. As these foam stabilizers, silicone-based ones are mainly used, which are added in an amount of 0.05 to 3.0% with respect to the resin composition, and the size of foam bubbles,
It is desirable to adjust the amount and state of foaming. The foam stabilizer has the same function as the defoamer, and the water-based urethane resin is usually
Since the defoaming agent is added, it is necessary to determine the amount of the foam stabilizer used in consideration of this amount of defoaming agent. If the defoaming agent in the water-based urethane resin sufficiently regulates the bubbles in the coating film, the foam stabilizer may not be added.

The pigment used in the resin composition includes, but is not limited to, titanium dioxide, calcium carbonate, mica, talc, clay, bentonite powder, kaolin and the like.

As other additives used in the resin composition, water-soluble polymers such as polyvinyl alcohol, hydroxyethyl cellulose, methyl cellulose and carboxymethyl cellulose, dispersants and film forming aids may be added if necessary.

Usually, the resin composition is prepared immediately before coating,
Immediately applied by the usual application means. Usually, the adjusted resin composition may be applied immediately, but the aqueous urethane resin and the foaming agent, the foaming aid, the foam stabilizer, the defoaming agent, the dispersant and the pigment are mixed at the time of coating to form a putty resin composition, Although it is applied by a usual application means such as a roll or a knife coater, more suitable results can be obtained by applying by the method previously applied (Japanese Patent Application No. 3-184263).

The foaming agent compounded in the resin composition decomposes to the extent that it is slightly heated to generate small bubbles, and the foaming aid promotes and cures foaming to form a strong coating film containing bubbles. Form.

When the resin composition contains a foam stabilizer or an antifoaming agent, the bubbles generated are further uniformly foamed and adjusted. The temperature at which the foaming bubbles uniformly foam and cure is preferably 40 to 80 ° C., more preferably 40 to 80 ° C.
It is 60 ° C. Bubbles are generated in the entire coating film in the foamed coating film, but the formation, amount, growth rate, etc. of the bubbles differ depending on the type and amount of the aqueous urethane resin and the foaming agent, the foam stabilizer, etc. Determined. The resin composition thus obtained is applied to wood-based materials such as plywood and particle board, and has no "eye-loss" and "twist" or "warp".
It is preferable as a wood material for secondary processing because it can be finished smoothly with a non-coated material and has good sanding suitability.

[0024]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples. In the examples and comparative examples, parts are based on weight.

Example 1 The water-based urethane resin used here is "Orestar UD50".
0 ”(manufactured by Mitsui Toatsu Chemicals, Inc.) was used. First, as the water-based urethane resin composition, formulations A, B, C and D in Table 1
I prepared one. Next, the foaming agents I and II shown in Table 2 were prepared.

[0026]

[Table 1]

[0027]

[Table 2]

Then, the aqueous urethane resin and the foaming agent were mixed in the combinations shown in Table 3 to prepare resin compositions AI to DII.
8 kinds were obtained.

[0029]

[Table 3]

For the resin compositions AI to DII, a mixture of an aqueous urethane resin and a foaming aid compound was used for testing 2.5 mm plywood (a back plate usually called Otsu board is also used on the front side, and cracks, pin holes, etc. (Having a defect of concave portion) is coated with a knife coater on the entire surface of 2.5 mm plywood at 50 to 100 g / m ² and then heated at 50 to 60 ° C. for 10 minutes to foam and cure to make the defective concave portion smooth or slightly. I made it into the convex part of.

As a result, there was no occurrence of "twist" or "warp" in the 2.5 mm plywood coated with the resin composition and dried, and there was no "clogging" of the sanding paper even after sanding. Further, the sanded 2.5 mm plywood was allowed to stand at room temperature for 10 minutes, but there was no "eye blemishes".

Comparative Example 1 The aqueous emulsion resin composition of Example 1 (Table 1) was applied under the conditions of Example 1 without adding a foaming agent.
As a result, although the 2.5 mm plywood coated with the resin composition and dried did not cause "twist" or "warp", the recesses were not sufficiently foamed and were still seen even after sanding. Therefore, the drying temperature is set to 90 to 100 ° C. and 10 to 2
When sufficient heating was performed for 0 minutes, the defect recesses were smoothed or smoothed slightly, but "twist" and "warp" occurred on the dried 2.5 mm plywood.

[0033]

According to the present invention, the volume shrinkage due to the "eye loss" after applying to plywood, which has not been achieved by the prior art,
It has been found that the prevention of "twist" and "warp" of the plywood and "clogging" during sanding can be achieved.

That is, in Comparative Examples outside the scope of the present invention,
The purpose of these phenomena was not achieved, the recesses were not sufficiently foamed, and the recesses were still seen even after sanding.
However, in the examples within the scope of the present invention, by adding a foaming agent to the aqueous urethane resin composition, foaming and curing are performed uniformly, and the defect recesses are smoothed, even though the drying temperature is low. Alternatively, the sanding paper was not clogged even if it was sanded with some convex portions, and a resin composition satisfying all of these phenomena could be obtained. The present invention has great significance because the influence on the wood quality and the plywood industry in which the situation of raw wood deteriorates will become greater and greater in the future.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C09D 5/00 PPT 6904-4J 5/34 PRC 7211-4J 175/00 PHM 8620-4J // C09K 3/10 D 9159-4H C08L 75:00 (72) Inventor Nagayoshi Hiroyoshi 7-1, 1-1 Hikoshimasako-cho, Shimonoseki-shi, Yamaguchi Prefecture Mitsui Toatsu Chemical Co., Ltd. (72) Inventor Koichi Tanaka Yamaguchi 7-1 1-1 Hikoshimasako-cho, Shimonoseki-shi, Shizuoka Mitsui Toatsu Chemical Co., Ltd.

Claims (4)

[Claims] 1. A resin composition comprising an aqueous urethane resin having a carboxyl group and a foaming agent. 2. A water-based urethane resin having a carboxyl group is obtained by reacting a diisocyanate with a polyol having a carboxylic acid to obtain a prepolymer having an isocyanate group, which is neutralized with a basic organic substance to obtain a polyamine and / or Alternatively, the resin composition according to claim 1, which is obtained by chain extension with deionized water. 3. The resin composition according to claim 1, wherein the foaming agent is selected from the group consisting of carbonic acid compounds and ammonium compounds. 4. The resin composition according to claim 1, wherein the carboxyl group content of the aqueous urethane resin is 25 to 100 in terms of acid value (calculated as solid content).