JPH0425124B2 - - Google Patents

Description

[Detailed description of the invention]

(a) Purpose of the invention (field of industrial application) This invention relates to a particle board. More specifically, the present invention relates to particle boards useful as various building materials such as flooring materials and wall materials, and furniture materials. (Prior art) A plate-shaped material made by integrally molding pieces of wood or other plant fibers (wood chips) with a synthetic resin adhesive has traditionally been used as a building material, and is generally called particle board. . Such particle boards are usually manufactured by drying wood chips of a predetermined size, adding a urea-based, melamine-based, or phenol-based adhesive, and press-molding them under heat. (Problems to be Solved by the Invention) However, such particle boards are inferior to ordinary building materials in water absorption/hygroscopicity and decay resistance. Therefore, it could not be used as a building material in places where water absorption, hygroscopicity, decay resistance, etc. are required. Furthermore, resistance to termite damage, such as termite resistance, was inferior to that of ordinary building materials. This invention has been made to solve the above problems. (B) Structure of the Invention According to the present invention, in a particle board formed by integrally molding a large number of wood chips using a synthetic resin adhesive, the wood chips are mixed with acetylated wood chips and untreated wood chips. There is provided a particle board characterized in that it is composed of mixed chips and chips. The most distinctive feature of this invention is that particle board is constructed by mixing acetylated wood chips with ordinary wood chips. The wood chips may be in either flake or wafer shape. Also, depending on the mixture, it may be flame retardant treated. Such acetylation treatment of wood chips is, for example,
The chips were added to a mixture of acetic acid and an acetylation catalyst (e.g., industrial sodium acetate, etc.) and heated to approx.
This can be easily carried out by reacting at 120 to 180°C for a period of ten minutes to several tens of minutes. In some cases, known acetylation methods using acetic anhydride or chloroacetic acid may also be applied. Although the degree of acetylation is not particularly limited, the above-mentioned treatment can usually acetylate the theoretical amount, that is, about 15 to 20% of the total number of hydroxyl groups in the cellulose molecules of wood chips. The acetylated wood chips thus obtained are used as a raw material for the production of particle board after being subjected to appropriate washing and drying treatments. The acetylated wood chips are mixed with ordinary wood chips that have not been subjected to acetylation treatment to produce particle board. The mixing ratio of acetylated wood chips and ordinary wood chips at this time can be about 1:9 to about 9-1 by weight, but is preferably about 1:4 to about 1:1. . The amount of acetylated wood chips mixed is 1/1 of that of untreated wood chips.
If it is less than 4, the improvement in rot resistance is insufficient and undesirable, and if it is more than the untreated chips, it becomes difficult to obtain a board with strength that can be used in actual use, as it becomes difficult to bond and integrate with synthetic resin adhesive. This is difficult and undesirable. The most preferred mixing ratio is from about 1:4 to about 2:1 acetylated wood chips:untreated wood chips. After suitably drying the above-mentioned mixed chips, the particle board of the present invention can be obtained by spraying a synthetic resin adhesive, filling it into a mold, and subjecting it to press molding under heating. As for the manufacturing conditions at this time, known methods can be applied as they are. For example, urea-based adhesives, which are conventionally used as synthetic resin adhesives,
Solutions of melamine or phenolic adhesives in organic solvents (usually about 7-14% by weight) can be used. Note that the unacetylated wood chips to be mixed with the above acetylated wood chips may be impregnated with various known insect repellents, and such impregnation treatment may inhibit the strength and characteristics of the particle board itself. Insect control treatment can be carried out efficiently without any problems. Therefore, according to another aspect, the invention includes:
A particle board made by integrally molding a large number of wood chips using a synthetic resin adhesive, characterized in that the wood chips are a mixture of acetylated wood chips and insect repellent-impregnated wood chips. The present invention also provides a particle board with the following characteristics. The mixing ratio of wood chips at this time is the same as above. Among these insect repellents, it is most preferable to impregnate termite repellents for use as building materials, and specific examples include phoxim (O, O-diethyl-o-(a-cyanobenzylideneamino) thiophosphate). ), sumithion (dimethyl-o-4-nitro-m-tolylthiophosphoric acid), chlorpyrifos (O,O-diethyl-
o-3,5,6-trichloro-2-pyridyl-phosphorothioate), tetrachlorvinphos (2
-Chloro-1-(2,4,5-trichlorophenyl)vinyl dimethyl phosphate), etc., Sevin (l-naphthyl methylcarbamate), Batusa (methylcarbamate -o-sec-
Carbamate compounds such as butylphenyl), vermethrin (3-phenoxybenzyl-3-(2,
Examples thereof include pyrethroid compounds such as (2-dichlorovinyl)-2,2-dimethyl-cyclopropanecarboxylate) and chlorine compounds such as chlordane. The specific impregnation treatment is carried out by immersing the wood chips in an organic solvent (for example, toluene) containing 0.3 to 1.0% by weight of the termiticide for several minutes to several tens of minutes. (Examples) Hereinafter, examples of the particle board of the present invention will be described in detail. Example 1 Wood chips cut into flakes with a shaving machine (average width of about 5 mm) are heated to a predetermined density (4 to 5 mm).
15%) sodium acetate (catalyst) aqueous solution so that the catalyst addition rate is 10% or more, and dry until completely dry. 1 kg of this wood chips, 300 ml of acetic anhydride
and stirred for 30 minutes while heating to 120 to 130°C to react. The obtained acetylated wood chips were taken out, washed with hot water, transferred to a cloth centrifuge, dehydrated for 5 minutes, washed again with hot water, and dried in a cloth centrifuge for 5 minutes. Dehydrate for a minute and wash repeatedly until the acetic acid odor disappears. This was dried until completely dry to obtain acetylated wood chips used in this invention.

[Table] Thus, it can be seen that particle board mixed with acetylated wood chips is excellent in both water absorption and decay resistance. Example 2 As unacetylated wood chips, wood chips impregnated with a termiticide obtained by immersing wood chips in a toluene solution (1% by weight) of an organic phosphorus compound (phoxim) as a termiticide for 20 minutes were used. A particle board of the present invention was produced in the same manner as in Example 1. Furthermore, acetylated wood chips and
The mixing ratio with termite-impregnated wood chips was 1:2. A 3 cm square specimen was cut from the particle board obtained in this way, placed in a container, and 200 worker ants and 20 soldier ants of the house termite were released into the container and left in this state for 3 weeks. The weight loss rate and mortality rate of the specimens were measured to evaluate termite resistance.
The results are shown in the table below along with comparative examples.

[Table] (c) Effects of the invention As described above, according to the particle board of the present invention, water absorption, hygroscopicity, and decay resistance are significantly improved, and the termite resistance itself is also improved. Therefore, it can be put to practical use even in a high humidity environment where conventional particle boards cannot be used, and can be used for a long period of time. Furthermore, the particle board of the present invention, which is constructed by impregnating unacetylated wood chips with an insect repellent, exhibits a strong insect repellent effect in addition to the above-mentioned effects, and is particularly ideal as a building material.

Claims (1)

[Scope of Claims] 1. In a particle board formed by integrally molding a large number of wood chips using a synthetic resin adhesive, the wood chips include acetylated wood chips and untreated wood chips in a ratio of 1:2. A particle board characterized by being composed of mixed chips having a weight ratio of ~1:1. 2. In a particle board formed by integrally molding a large number of wood chips using a synthetic resin adhesive, the ratio of wood chips to acetylated wood chips and insect repellent-impregnated wood chips is 1:2 to 2.
A particle board characterized by being composed of mixed chips with a weight ratio of 1:1. 3. The particle board according to claim 2, wherein the insect repellent is an anticide.