JPH0327199A - Organic fiber board and preparation thereof - Google Patents

Abstract

PURPOSE:To prepare a fiber board slightly absorbing water, having excellent dimensional stability and exhibiting flame-proof function by acetylating organic fibers, filling or adhering a non-flammable inorganic compound it or to the cell holes, outer periphery, etc., of the fibers and integrally molding the fibers with an adhesive substance. CONSTITUTION:Organic fibers (e.g. fibers prepared by cutting needle-leaf trees or wide leaf trees into chips and subsequently opening the fibers of the chips and having a length of 1-30mm and a thickness of 2-300mum) is acetylated, and a non-flammable inorganic compound (e.g. calcium compound or magnesium compound) is filled in, adhered to or stuck to the cellular holes, cellular hole inner walls and outer periphery of the fibers. The fibers are subsequently integrally molded with an adhesive substance (e.g. a urea resin or melamine resin) to provide the objective fiber board.

Description

[Detailed description of the invention] Industrial application fields> The present invention relates to an organic fiberboard and a method for manufacturing the same.

<Prior art> Wood modification technology is known in which nonflammable inorganic compounds are dispersed and fixed in the cell pores of wood in the state of wood sticks, boards, or veneers to make them flame retardant (Japanese Unexamined Patent Application Publication No. 1983-1982). 244502).

According to this prior art, in order to impart the required flame retardancy to wood, a nonflammable inorganic compound must be added to
It is necessary to disperse 0% by weight or more.

Furthermore, organic fiberboards manufactured by compression molding organic fibers obtained by cutting various softwood or hardwood materials into chips and defibrating the chips are known.

<Problems to be Solved by the Invention> However, in the above-mentioned conventional wood modification method, non-combustible inorganic compounds of 40% or more of the absolute dry weight of the wood in the form of a stick, board or veneer are used. It is actually extremely difficult to disperse. According to the above-mentioned prior art, as a method for dispersing nonflammable inorganic compounds, wood is impregnated with an aqueous solution of a water-soluble inorganic compound, and then a compound that reacts with the inorganic compound to produce an insoluble inorganic compound is added. , and a method in which wood is impregnated with a sol of an insoluble inorganic compound and then dried, but in either case, it takes a long time to achieve sufficient impregnation, and more of the impregnation occurs in the periphery of the wood. Therefore, it is difficult to uniformly disperse the particles into the interior.

Furthermore, when using this method, the nonflammable inorganic compound impregnated in large quantities around the wood becomes powder after drying and adheres to the surrounding area, impairing the surface cosmetic properties, so it cannot be used as is. This required a process such as washing with water to remove it. This removal process is not only troublesome, but also uneconomical because it is difficult to recover the removed nonflammable inorganic compounds, and it also has many problems such as the need for an additional waste liquid treatment process. was.

In addition, conventional organic fiberboard lacks dimensional stability because the board expands or contracts as the organic fiber absorbs moisture and dries, resulting in warping or cracking. This caused problems such as corrosion occurring from inside the board as a result of contaminants entering the board.

Means for Solving the Problems> In view of the current situation, the present inventor has conducted extensive research in order to provide an organic fiberboard that has non-combustible properties and has excellent dimensional stability against moisture absorption and release. As a result of repeated efforts, the present invention has been completed.

That is, the organic fiberboard according to the present invention is acetylated and has a nonflammable inorganic compound filled in, attached to, or fixed to the inside of the cell pores or the inner wall surface and outer periphery of the cell pore, and a certain organic fiber is adhesively molded and integrated. It is characterized by consisting of: Furthermore, the method for producing an organic fiberboard according to the present invention includes acetylating organic fibers, and then filling or adhering a nonflammable inorganic compound into the cell pores of the organic fibers or the inner wall surfaces of the cell pores and the outer periphery of the organic fibers. The method is characterized in that the organic fibers thus treated are fixed and integrally molded using an adhesive substance.

The organic fiber used as a raw material in the present invention is a fiber obtained by chipping softwood such as pine, cedar, and cypress, or hardwood such as lauan, capor, chestnut, and poplar, and then defibrating it in accordance with a conventional method. Generally, most of them are about 1 to 30 mm in length, 2 to 300 μm in diameter. These organic fibers generally have a structure like a bundle of conduits and tracheids or cells, and the cell walls at the outer periphery of the fibers are often torn or cracked. In the present invention, "cell pore" means, for example, a void within a conduit or tracheid.

Such organic fibers are first subjected to acetylation treatment according to a conventional method. For example, organic fibers are impregnated with an aqueous solution of metal acetate such as sodium acetate or potassium acetate without a catalyst or as a catalyst, dried, and then acetic anhydride,
Immerse in an acetic anhydride reaction solution such as chloroacetic anhydride, and
By performing a heating reaction at o-150°C for several minutes to several hours, the hydroxyl groups in the organic fibers are replaced with acetyl groups,
Next, the acetylation treatment is performed by discharging the excess reaction solution, washing and drying.

In this way, the cell pores of the acetylated organic fibers are filled with a nonflammable inorganic compound, or the nonflammable inorganic compound is fixed or adhered in a layer along the inner wall of the cell pores, and also on the outer periphery of the organic fiber. Nonflammability treatment is performed by fixing or adhering the nonflammable inorganic compound. This nonflammability treatment can be performed, for example, by the following steps. That is, after acetylated organic fibers are thoroughly immersed in an aqueous solution of water-soluble inorganic salts (hereinafter referred to as "liquid I"), the organic fibers are dried to leave them in a surface dry state. Alternatively, it is kept in an absolutely dry state, and if necessary, the split crystals of the first liquid deposited on the surface are removed. Next, a compound liquid (hereinafter referred to as "second liquid") that reacts with the first liquid to produce an insoluble, nonflammable inorganic compound is added and mixed using a blender, spray, etc. to form the second liquid. Impregnate organic fibers. In this way, a nonflammable inorganic compound is formed by the reaction between the first liquid and the second liquid in the organic fiber. Since this nonflammable inorganic compound is insoluble, it is filled in, adhered to, or fixed in the cell pores of the organic fiber or on the inner wall surface of the cell pore and the outer periphery of the fiber.

Nonflammable inorganic compounds are also attached or fixed to the inner wall surface of the cell pores of organic fibers and the outer periphery of the fibers, so even if there are cracks or crevices in the cell walls of the outer periphery of the fibers, it is necessary to close or fill them. This means that nonflammable inorganic compounds exist in the form of In order to increase the reaction efficiency between the first liquid and the second liquid, the addition and mixing of the second liquid is carried out under a heated atmosphere, especially at 40°C.
It is preferable to conduct the reaction at a temperature of 0°C or higher, more preferably 5000°C or higher.

Examples of nonflammable inorganic compounds include calcium compounds,
Magnesium compounds, aluminum compounds, barium compounds, lead compounds, zinc compounds, silicate compounds, etc. are preferably used. Furthermore, the nonflammable inorganic compound must be mixed in at a ratio of 33% by weight or more to the organic fibers, and if it is less than this, sufficient fireproof performance cannot be obtained.

The present invention can be achieved by adding an adhesive to the acetylated and nonflammable organic fibers, adjusting the moisture content, forming a mat, and pressing or hot pressing depending on the curing conditions of the adhesive. is obtained from fiberboard. The adhesive used in this case is, for example, urea resin. Thermosetting adhesives such as melamine resins and phenolic resins, thermoplastic adhesives such as vinyl acetate adhesives, adhesives such as rubber resins, two-component reactive resins, and moisture-curing resins can be used alone or A plurality of them can be mixed and used.

Furthermore, in the present invention, since a nonflammable inorganic compound is fixed or attached to the outer periphery of the organic fiber, it is necessary to take care not to reduce the adhesive strength due to this nonflammable inorganic compound, and an adhesive with good permeability is used. It is preferable to use Furthermore, adding a flame retardant to the adhesive or using an adhesive that has been subjected to flame retardant treatment in advance is beneficial in further improving the fire retardant performance of the resulting organic fiberboard.

<Function> The organic fibers in the organic fiberboard are made less likely to absorb water by acetylation treatment, and are made flame retardant by impregnation or attachment of a nonflammable inorganic compound.

Example: Radiata pine chips were heated at 160°C. 7hy/c
After boiling at m2 for 3 minutes and defibrating with a defibrator-type 7-iner, the dried wood fibers were immersed in acetic anhydride and heat-treated at 120°C for 1 hour to perform acetylation. Immediately after the reaction was completed, the mixture was washed with water and dried to obtain acetylated wood fibers. The weight increase rate due to this acetylation treatment was 17%.

Next, the acetylated wood fibers were immersed in an aqueous solution containing barium chloride as the main component for 10 minutes for diffusion treatment, the solution was squeezed out and dried with hot air until the moisture content reached 7%, and then ammonium phosphate was added using a blender. A non-combustible inorganic compound consisting of insoluble barium phosphate and barium hydrogen phosphate is formed in the cell pores of the wood fiber or on the inner wall surface of the cell pore and the outer periphery of the fiber. Then l
The moisture content was adjusted to 7% by hot air drying at 15°C.

The weight increase rate due to this nonflammability treatment was 36%.

Using organic fibers that have been acetylated and made non-combustible, a melamine resin adhesive containing aumonium phosphate is used. An organic fiberboard is obtained by adding 100% of the organic fiber and heat-pressing it at 140°C for 3 minutes.

When this organic fiberboard was subjected to a quasi-inflammability test according to JIS, it passed.

<Effects of the Invention> In the organic fiberboard of the present invention, since the organic fibers are acetylated, the fibers are difficult to absorb moisture, and therefore the expansion or contraction of the board due to moisture absorption and drying is substantially reduced. It has excellent dimensional stability. Also,
Corrosion problems due to contaminants entering with moisture are solved.

Furthermore, since the organic fibers are filled with or adhered to a nonflammable inorganic compound in the cell pores or on the inner wall surface of the cell pores and the outer periphery of the fibers, the obtained organic fiberboard can exhibit excellent fireproofing performance. In the present invention, the nonflammable inorganic compound is filled or attached to the organic fibers themselves, and each organic fiber is sufficiently and evenly treated to be nonflammable.

Claims (3)

[Claims] (1) Organic fibers that have been acetylated and are filled with, adhered to, or fixed to the cell pores or the inner wall surface and outer periphery of the cell pores with a nonflammable inorganic compound are integrally bonded and molded. Organic fiberboard. (2) The organic fiberboard according to claim 1, wherein the nonflammable inorganic compound is contained in an amount of 33% or more by weight of the organic fiber. (3) Organic fibers are acetylated, and then a nonflammable inorganic compound is filled, adhered, or fixed to the cell pores of the organic fibers or the inner wall surface of the cell pores and the outer periphery of the organic fibers, and the thus treated organic fibers are treated with a nonflammable inorganic compound. 1. A method for producing an organic fiberboard characterized by integrally molding fibers using an adhesive substance.