JPH11151702A - Woody plate and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for dimensional stabilization of woody plates which provides high productivity and cost advantage. SOLUTION: In a woody plate, a heat-compacted layer impregnated with a glyoxal resin is formed at least on one side of a woody substrate. By the heat compaction of the surface on which the glyoxal resin is applied, the impregnation and adhesion of the resin can be achieved easily. By the impregnation carried out under high pressure heat compaction of the substrate surface, the surface layer increases its density and fixed firmly so that a woody plate is obtained in which not only the dimensional stability but the surface strength and the flexural strength are improved remarkably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dimensionally stabilized wooden board and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, WPC, acetylation, etherification, polyethylene glycol, formalization and the like have been implemented or proposed as techniques for improving the dimensional stability of wooden boards.

[0003]

However, the above-mentioned prior art requires large-scale facilities, requires a long time for treatment, discolors or embrittles a wooden material with a treating agent, or reduces the amount of the treating agent. Both have some disadvantages such as toxicity and problems in the treatment of waste liquid, and cannot achieve both productivity and cost.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a technique for stabilizing the size of a wooden board, which is excellent in productivity and advantageous in cost.

[0005] In order to achieve this object, a wood board according to the present invention according to the first aspect is characterized in that a wood substrate is formed on at least one side with a glyoxal resin impregnated and fixed layer formed by hot pressing. .

Further, in the method for manufacturing a wooden board according to the present invention, a glyoxal resin is applied to at least one surface of a wooden substrate, and the applied glyoxal resin is pressed by heat and pressure. It is characterized in that it is impregnated and fixed to form an impregnated and fixed layer of glyoxal resin.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION As a wooden substrate used in the present invention, a sawn timber, a laminated veneer, a plywood, a fiberboard, a particle board, a laminated wood and the like are suitably used.

A glyoxal resin is applied to at least one surface of such a wooden substrate using an application device such as a roll coater, a flow coater, a curtain coater, a spray coater, or a spray.

The wood substrate coated with the glyoxal resin is hot-pressed by a hot-pressing device such as a hot press or a hot roll press to impregnate and fix the applied glyoxal resin, and to impregnate and fix the glyoxal resin. To form

[0010] In this hot pressing, the hot plate can be brought into contact with the surface of the wooden substrate or pressed with a low pressure to fix and impregnate the glyoxal resin. Alternatively, a high pressure may be applied to the surface of the wooden substrate with a hot platen to compress and fix the surface of the wooden substrate while impregnating and fixing the glyoxal resin.

The glyoxal resin is an initial condensate composed of urea, glyoxal and formaldehyde, and the molar ratio thereof is preferably from 1: 0.5 to 1: 1 to 3.

The glyoxal resin impregnated and fixed on the wooden substrate is insolubilized by a self-polycondensation reaction.
It is insolubilized by an ether bond with a hydroxyl group of cellulose or the like in the wooden substrate.

A catalyst is added to the glyoxal resin as needed. As the catalyst, a magnesium chloride catalyst, an organic amine salt catalyst, a zinc nitrate catalyst, or the like can be used. Addition of such a catalyst activates the self-polycondensation reaction of the glyoxal resin and promotes insolubilization. For this reason, 0.5 to 23% by weight of the non-volatile component of the glyoxal resin is used. Is preferred. There is no problem if the catalyst is added in an amount of 23% by weight or more, but the effect is not significantly improved, so that the practical meaning is poor.

Further, a polyhydric alcohol is added to the glyoxal resin as required. As the polyhydric alcohols, ethylene glycol, propylene glycol, glycerin, pentaerythol and the like can be used alone or in any combination. Polyhydric alcohols have a weight ratio of 8 to the nonvolatile components of the glyoxal resin.
It is preferable to mix in the range of 0:20 to 60:40. By adding polyhydric alcohols, in addition to the glyoxal resin being ether-bonded to hydroxyl groups of cellulose or the like in the wood-based substrate, the hydroxyl groups of the polyhydric alcohols are also ether-bonded, so that the crosslink density is high and condensed. Promotes insolubilization.

When a polyhydric alcohol is added to a glyoxal resin for use, it is preferable that the molecular weights of the glyoxal resin and the polyhydric alcohol are similar. When a polyhydric alcohol having a lower molecular weight or a higher molecular weight than the glyoxal resin is added, the glyoxal resin and the polyhydric alcohol are separated without being uniformly penetrated into the wood fiber, and a sufficient ether bond is formed. To be hindered,
The effect of insolubilization cannot be obtained as expected.

In the present invention, it is essential to impregnate and fix the glyoxal resin on at least one surface of the wooden substrate. However, the glyoxal resin is impregnated and fixed on both surfaces of the wooden substrate, and further on the entire surface including the four-sided edge. Is also good.

According to the wood board of the present invention, a glyoxal resin is impregnated and fixed on at least one surface of the wood board, and is insolubilized by a self-polycondensation reaction of the glyoxal resin and an ether bond with a hydroxyl group such as cellulose in the wood board. However, when a polyhydric alcohol is added, the glyoxal resin is also ether-bonded to the hydroxyl group of the polyhydric alcohol to form a water-insoluble reactant. Reduced and exhibit extremely good dimensional stability. In addition, since moisture is absorbed and released between hydroxyl groups of polyhydric alcohols, dimensional stabilization can be achieved while maintaining the original properties of wood materials.

Further, according to the present invention, the surface of the glyoxal resin is hot-pressed after application, so that the glyoxal resin is easily impregnated and fixed.

When the hot-pressing is performed by applying a high pressure to the surface of the wooden substrate and the surface of the wooden substrate is compressed and impregnated with glyoxal resin, the surface of the wooden substrate is compressed. Since the densified surface layer is fixed by impregnating and fixing the glyoxal resin, it is possible to manufacture a wooden board having not only dimensional stability but also significantly improved surface strength and bending strength. it can.

The surface of the glyoxal resin-impregnated fixed layer of the wooden board of the present invention is subjected to a base treatment such as a sealing treatment, a sealer treatment, an undercoating treatment, a sanding treatment, etc., if necessary, and then is subjected to coloring coating or pattern printing. , An arbitrary decorative layer can be formed. Alternatively, after performing the same base treatment as necessary, with or without an adhesive, veneer, artificial veneer, veneer or artificial veneer with a backing material stuck thereon, or decorative paper, cosmetic synthetic resin The decorative layer may be formed by sticking a decorative sheet such as an impregnated paper or a decorative synthetic resin film.

[0021]

According to the present invention, a wooden board having low hygroscopicity and excellent dimensional stability can be obtained.

Claims (2)

[Claims] 1. A wood board, characterized in that a glyoxal resin-impregnated fixed layer is formed on at least one surface of a wood-based substrate by hot pressing. 2. A method for applying a glyoxal resin to at least one surface of a wood-based substrate and then hot-pressing the wood-based substrate to impregnate and fix the applied glyoxal resin to form a glyoxal resin-impregnated fixed layer. A method for producing a wooden board, characterized by the following.