JP2983079B2 - Method for producing synthetic resin-injected wood - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of impregnating and hardening a wood material containing a large amount of quinones with a radical polymerization type resin solution.
The present invention relates to a method for manufacturing a synthetic-resin-injected wood material having improved durability, hardness, and cosmetic properties.

[0002]

2. Description of the Related Art Wood materials injected with synthetic resin (hereinafter referred to as WPC)
This is called a radical polymerization type resin liquid such as acrylic or polyester resin is injected into a void portion in the wooden material and cured to improve hardness and durability, which are defects of the wooden material. Such WPC materials are widely used for floor materials, stairs, furniture surface materials, and the like.

The reason for using a radical polymerization type resin liquid as a synthetic resin liquid to be injected into a wood material is that this resin not only has a high heat-curing speed and good productivity but also has a solvent such as styrene or methyl methacrylate. At the same time, by adding a compound that is capable of radical polymerization and curing itself, the viscosity of the resin liquid can be reduced to facilitate penetration into the wood material.Furthermore, the generation of gas during heat pressure can be minimized. This is to prevent uneven distribution of punctures and resins and to increase the resin filling in the wood material.

[0004]

However, wood cedars, zelkova, walnuts, and the like, which are high-grade precious woods used for high-quality building materials and furniture, contain a large amount of quinones in their woody materials. Therefore, when a radical polymerization type resin solution is directly injected into such a wood material, there is a problem that polymerization is inhibited by quinones and uneven filling occurs, and the resin is not completely cured and stickiness remains.

Further, when a large amount of wood is impregnated many times in the radical polymerization type resin liquid tank, the liquid is contaminated by extracting the components of the wood, and if used in that state, there is a possibility that curing inhibition and coloring contamination may occur. There is. Therefore, even if an attempt is made to extract the polymerization-inhibiting component in advance with hot water, alcohol, or the like, it cannot be completely removed from the complicated and fine structure of the wooden material, and the above problem cannot be solved.

The present invention has been made in view of such problems, and has been developed for a wood material containing a large amount of quinones that cause poor curing of a radical polymerization type resin solution.
An object of the present invention is to provide a method for producing a synthetic-wood-injected wood material for the purpose of improving durability, hardness, cosmetic properties, and the like by completely curing a resin.

[0007]

In order to achieve the above-mentioned object, a method for producing a synthetic resin-injected wood material according to the present invention is disclosed in
A wood-based material containing a large amount of quinones that cause polymerization inhibition when a polymerized resin solution is injected, a condensed polymerized resin solution such as a phenolic resin is added in advance to the cell lumen of the wood-based material. And then impregnating and curing the radical polymerization type resin liquid into the voids.

[0009]

[Function] If the condensation polymerization resin solution is impregnated before injecting the radical polymerization type resin solution into the wood material, the condensation polymerization resin and a part of the polymerization inhibiting substances such as quinones contained in the wood material are converted. It reacts and denatures to become a substance that does not inhibit radical polymerization.

Further, since the condensation polymerization resin solution is injected in the form of an aqueous solution, it easily penetrates into the cell walls of the wooden material which is hydrophilic and volatilizes the water after the infiltration, so that the cell cavity of the wooden material can be removed. It cures while filling the small voids in the cell wall with the large voids remaining. for that reason,
The inhibitor is blocked so as not to float and does not inhibit the radical polymerization.

Thereafter, when the radical polymerization type resin liquid is injected into the wooden material, the radical polymerization type resin liquid penetrates into the voids in the wooden material, and fills and hardens into the remaining large voids.

Accordingly, the dimensional stability is imparted by the condensation polymerization resin cured in the cell wall, and the difference in behavior between the resin and the radical polymerization type resin filled in the large void is reduced. Thus, a resin-injected wood material that prevents cracks and contaminants from penetrating can be obtained.

[0013]

EXAMPLES Next, examples of the present invention will be described in detail. An aqueous solution of a condensation polymerization resin adjusted to have a non-volatile content of 40% by weight or less, preferably 5 to 25% by weight, by adding an appropriate amount of water to a fiber is prepared. It is poured into undried wood having a water content below the saturation point (even a water content of about 50% is acceptable). As the condensation polymerization resin, urea resin, melamine resin, phenol resin, furan resin, and the like are used, and are injected into the wood material as an aqueous solution adjusted to the above concentration.
If this is the case, impairment of the impregnation of the radical polymerization type resin solution to be described later occurs, so the content is adjusted within the above range.

When an acid such as toluenesulfonic acid, xylenesulfonic acid, benzenesulfonic acid or the like is added to the aqueous solution of the condensation polymerization resin, the low molecular weight compound in the wood material component is hardly modified into a quinone structure together with the catalytic action. It is considered to be effective in preventing the formation of radical polymerization inhibitors.

The method of injecting the condensation polymerization resin solution into the wooden material is carried out by a reduced pressure or pressure injection method, but may be carried out by a dipping or diffusion method.
A method and conditions suitable for the shape and size of the material, permeability, and tree species may be appropriately selected so as to be impregnated. In addition, as the polycondensation resin to be injected, a low molecular weight resin having a molecular weight of 200 or less is used to facilitate the penetration of the wood material into the cell wall. On the other hand, the wood material to be injected may be any of a thin plate such as a veneer, a thick lumber such as a square or plate material, a hollow material, a plywood, a laminated wood, and the like.

When the aqueous solution of the condensation polymerization resin is injected into the wooden material using such an appropriate injection means, a large amount of water is present in the aqueous solution of the condensation polymerization resin. For example, the aqueous solution of the condensation polymerization resin easily penetrates.

After injecting the aqueous condensed polymer resin solution into the wood material, the resin-injected wood material is heated while paying attention to the occurrence of warpage, cracks, etc., to volatilize the water in the aqueous condensed polymer resin solution impregnated in the wood material. Exclude. In addition, you may perform using a hot-air dryer as a heating and drying means.

When water, which is the solvent in the aqueous solution of the condensation polymerization resin, is volatilized in this manner, most of the water is mainly scattered into large cavities such as cell cavities of the wood material and released from the cavities to the outside of the material. Thus, voids (cell lumens) not filled with the resin are formed, while small voids in the cell wall remain filled with the resin.

At this time, the curing of the resin starts even at a low temperature such as the drying by the heating means, and the curing is gradually performed after the water in the wooden material is volatilized as described above. This is preferable because it does not occur. Such heating and drying treatments are 80-160 ° C depending on the thickness of the wood.
For several minutes to several hours.

When the rate of weight increase of the wood material after the injection polymerization of the condensation polymerization resin solution is 5 to 40%, preferably 10 to 25%, the presence of voids such as cell cavities in the wood material is maintained. As a result, the condensation polymerization resin is sufficiently injected into the wall and hardened without impeding the injection of the later-described radical polymerization type resin solution, so that good dimensional stability and antiseptic and insect repellency can be secured.

In this case, if the resin filling rate in the void portion of the wood material increases, adverse effects such as coloring by the resin and cost increase occur. Therefore, the concentration of the aqueous solution of the condensation polymerization resin is limited to the above range of 40% by weight or less. The adjustment of.

After the aqueous solution of the condensation polymerization resin is injected into the cell walls of the wooden material and cured, the radical polymerization type resin liquid is then filled into the voids formed by the elimination of water in the wooden material and cured. Let it.

This filling and curing step comprises injecting a resin solution containing a radical polymerizable monomer alone or a polymerizable prepolymer as a main component or a mixed resin solution thereof into the condensed polymer resin-injected wood material. Can be carried out under reduced pressure or under reduced pressure.

As the radical polymerizable monomer used in this step, styrene monomer, methyl methacrylate, styrene oxide, epichlorohydrin, divinylbenzene and the like can be mentioned.

Examples of the radical polymerizable prepolymer include vinyl polymer acrylate, melamine polymerizable acrylic prepolymer, unsaturated polyester prepolymer, acrylic urethane prepolymer and epoxy prepolymer. In addition, a reaction initiator, a plasticizer, a coloring agent, and / or a flame retardant can be appropriately added to the above resin liquid.

The treated wood material impregnated with the resin liquid by the above method is subjected to the next curing step. In this step, if necessary, the wood material is heated under pressure at 80 to 250 ° C. with a hot plate, or is wrapped so that the resin liquid is not scattered, and heated at normal pressure.

Next, specific examples of the present invention will be described. Example 1 A cedar veneer having a thickness of 0.5 mm, a width of 10 cm, a length of 1 m and a water content of 15% was coated with an aqueous urea resin solution having a resin nonvolatile content of 15% by weight under reduced pressure of 40 Torr for 30 minutes at 5 kg / cm ² . Pressure reduction and pressure injection were performed under pressure for 30 minutes. Next, the resin-injected veneer is dried in a hot air dryer at 60 ° C. for half a day, and then heated at 140 ° C. for 45 minutes by a hot-plate press, whereby a urea resin-injected hardened wood material having a weight increase rate of 23% is obtained. I got

Next, a resin solution obtained by adding a small amount of a polymerization initiator (benzoyl peroxide) to a mixture of an addition-polymerizable resin of unsaturated polyester: methyl methacrylate = 50: 50 is added to the urea resin-injected and cured wood material. The injection was carried out by a reduced pressure method. After the injection, the substrate was subjected to a heat and pressure treatment at 130 ° C. for 30 minutes to obtain a resin-injected and cured cedar veneer modified without causing curing failure.

The treated veneer thus obtained had a wet tarnish color with the appearance maintaining the color tone characteristic of wood. In addition, the addition polymerization type resin was completely filled in the large void portion such as the cell cavity of the veneer, and was excellent in durability, hardness and stain resistance.

Example 2 In the above Example 1, a zelkova veneer was used in place of the cedar veneer, and a melamine resin aqueous solution was injected into the zelkova veneer in place of the urea resin aqueous solution under the same conditions as in Example 1 and cured. I let it. The subsequent resin injection treatment with the addition polymerization type resin mixture was performed under the same processing conditions as in Example 1 above. The treated veneer thus obtained had good cosmetic properties and excellent physical properties such as durability and hardness.

In Example 1, a teak veneer was used in place of the cedar veneer, and a phenol resin aqueous solution was injected into the teak veneer and cured in place of the urea resin aqueous solution under the same conditions as in Example 1. The subsequent resin injection treatment with the addition polymerization type resin mixture was performed under the same processing conditions as in Example 1 above. The treated veneers thus obtained were obtained in Examples 1 and 2
In the same manner as in the above, it had good cosmetic properties and was excellent in physical properties such as durability and hardness.

[0029]

As described above, according to the method for producing a resin-treated wood material of the present invention, a wood solution containing a large amount of quinones is previously coated with a condensation polymerization resin solution such as a phenolic resin. After impregnated and hardened so that voids such as cell cavities remain, the above-mentioned voids are impregnated and hardened with a radical polymerization type resin solution. Nevertheless, it is possible to convert the wood material of a tree species, for which WPC treatment has been difficult, to WPC because it contains a large amount of quinones.

In addition, during the WPC treatment, the condensation polymerization resin solution is injected in the form of an aqueous solution, so that the condensation polymerization resin solution can be easily impregnated into even small voids in the cell wall of the wood material. In addition, by evaporating the water after the impregnation, large voids such as the cell lumen of the wood can be hollowed out.

Accordingly, dimensional stability can be imparted by the resin injected into the cell wall and cured, and the large voids can be easily filled with the radical polymerization type resin solution. The difference in behavior with the radical-polymerized resin liquid is reduced, and no void is formed between the resin and the cell wall due to water absorption or the like, and a resin-injected wood material that prevents cracks and contaminants from entering can be obtained. .

In addition, coloring contamination of the radical polymerization type resin liquid is reduced, poor curing is prevented from occurring, and adjustment of the pot life is facilitated.

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shinji Miura 2-3-18 Nakanoshima, Kita-ku, Osaka Daiken Kogyo Co., Ltd. (58) Field surveyed (Int. Cl. ⁶ , DB name) B27K 3/15

Claims (1)

(57) [Claims] 1. When a radical polymerization type resin solution is injected,
After a wood material containing a large amount of quinones that cause the synthesis inhibition, a condensation polymerization resin solution such as a phenol resin is impregnated and cured in advance so that voids such as cell cavities of the wood material remain, and then radical polymerization is performed. A method for producing a synthetic resin-injected wood material, comprising impregnating and hardening a mold resin liquid into the void.