JPH0623716A - Production of reinforced wooden board - Google Patents

Abstract

PURPOSE:To simplify equipment by simultaneously performing the molding and internal formalization of a wooden board by changing over steam to mixed gas by utilizing the small steam jet orifices preliminarily provided to a hot plate during a hot press molding process due to a steam injection press to inject the gas. CONSTITUTION:Wood chips coated with a thermosetting resin are formed into a mat M with definite thickness by a forming machine 4 to be transferred to an injection press 6. The mat M is pressed by press plates 6, 9 and heated in a compressed state by the steam injected from the small holes 2 of hot plates 8', 9' and the adhesive is thermally cured to mold a wooden board having medium density. After the completion of hot pressing, the supply of steam is stopped to discharge steam to the atmosphere. At this point of time, the mixed gas of formaldehyde separately prepared to be stored in a gas sump 1 and sulfur dioxide is injected from the small holes 2 and passes through the board M to be drawn to the small holes on the opposite side to be circulated to form a formalized wooden board 10. As a result, a formalizing process can be simplified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a porous wood board such as a fiber board or a particle board which has a small dimensional change due to absorption / dehydration and which maintains rigidity when wet and does not deteriorate in strength.

[0002]

2. Description of the Related Art Generally, medium density fiberboard and particle board (hereinafter simply referred to as "wood board")
In the above, the board was stretched, shrunk or swelled due to moisture, water, or drying, and the size of the board was greatly changed. Especially, when the board was wet, the physical properties of the board were remarkably deteriorated.

Therefore, the wooden boards used up to now have problems in that their use is restricted because problems often occur due to instability of dimensions when they are used.

[0004] For the purpose of solving such a problem, the applicant of the present invention pays attention to the porosity of the wooden board having a specific gravity of this kind, and formalizes the surface layer or the inside thereof to form a wet board. Has developed a manufacturing method for wood-based boards that can prevent deterioration of the physical properties of wood and that can surely improve discoloration of the board and dimensional stability during absorption and dehydration.
No. 245 is a patent application.

The technical contents of the invention relating to the above patent application are as follows:
A wood material that has a density of 0.2 to 0.9 g / cm ³ by applying an adhesive to the board raw material obtained by disintegrating wood into fibrous material or crushing it into shavings or powder granules, hot pressing As a board, the board is set by longitudinally cutting the inside of the reaction apparatus of the gas circulation system, and a mixed gas of sulfur dioxide as a catalyst and a formaldehyde source such as trioxane, tetraoxane, and paraformaldehyde in a gas phase is introduced into the apparatus, Gas is penetrated to the front and back layers of the wooden board or inside to perform formalization.

[0006]

However, in order to effectively formalize the wood board after it has been formed, it is set in a reactor of a gas circulation system and heated to about 120 ° C. Therefore, since it was necessary to process gas, the size of the equipment was increased, and a low-cost formalized board could not be obtained in terms of fuel consumption.

[0007]

The present invention solves the above-mentioned problems by improving the conventional technique for manufacturing a formalized board.

That is, the present invention is based on the premise that a steam injection press, which has been conventionally known as a manufacturing apparatus for this type of wood board, is used, and is defibrated or crushed.
In the process of forming a mat of wood board raw material obtained by applying a thermosetting resin adhesive to form a thermocompression plate by a steam injection press, the mat is pressed and the adhesive is thermoset, and formaldehyde is added. By injecting a mixed gas of the source and sulfur dioxide (hereinafter simply referred to as "mixed gas") from one surface of the board in a compressed state, it penetrates in the thickness direction of the board and is recirculated through a suction and circulation pump to make it woody. A method of efficiently performing internal formalization simultaneously with the board formation was used.

[0009]

In the present invention according to the above-described structure, the formalization of the board is carried out simultaneously with the plate forming process in the steam injection press, so that the mixed gas is separately injected as in the conventional case. It does not require a heating process, etc., and has a special effect that the process can be shortened and large-scale equipment can be omitted.

[0010]

EXAMPLES The structure of the present invention will be described in more detail below with reference to one example. The main part of the steam injection press shown in FIG. 1 is a conventionally known device, but in carrying out the present invention. The characteristic part of the gas reservoir is the gas reservoir indicated by the reference numeral 1, and the reference numeral 2 is
3 are a plurality of small holes for injecting mixed gas penetrating the upper and lower heating plates 8'and 9 ', and a pump for circulating mixed gas of 3.

The apparatus will be described in more detail. In the figure, 4 is a homing machine, which separately hoses fibers or chips coated with an adhesive into a mat having a constant thickness, and transfers them to a steam injection press 6 by a conveyor 5. Then, the press side conveyor 7 is continuously connected.
The mat (M) is pressed by the upper and lower press plates 8 and 9, and steam is jetted at a time from the small holes 2 ... Rapidly 12
Heat to above 0 ° C. This heating heats the adhesive to form a medium-density wood board with a predetermined compression ratio, which is similar to the plate-forming technology by the steam injection press before suspension, but in the present invention, the press plate 8 is used.・ A large number of small holes 2 for jetting steam, which are preliminarily provided in the heating plates 8'and 9'of 9
・ By using 2 ... or by using a small hole for mixed gas injection, which is separately provided, after the completion of thermal pressure by steam injection, the supply of steam is stopped and the steam in the board is released to the atmosphere. On the other hand, the mixed gas prepared separately and stored in the gas reservoir 1 is switched to, and the mixed gas is injected from the small holes 2 ...

While this mixed gas penetrates the wood board and is sucked into the small holes 2.2 of the hot plates 8'and 9'on the opposite side and circulates inside the board via the gas circulation pump 3. The formalized wood board 10 is formalized from the press machine and sent to the subsequent cooling and cutting steps to be a product.

The gas reservoir 1 is not limited to the position shown in the embodiment, but may be provided on the upper or lower press plate 8 or 9, and a large number of small holes 2 for injecting a large amount of steam and mixed gas.・ 2 ・
The structure of the press plates 8 and 9 including the hot plates 8 ′ and 9 ′ provided with ··· is not limited to that of the embodiment, and all structural changes within the scope of the present invention are included. is there.

It is most efficient to provide the small holes 2 for injecting the mixed gas on the upper or lower press plate surface.
Even if the mixed gas is injected and injected from the wood mouth surface (side surface) side around the board in the pressed state, the formalization which is the object of the present invention and simultaneous with the wood board forming plate can be achieved. .

[0015]

As described above in detail, according to the present invention, since the formalization by the mixed gas can be simultaneously performed in the pressing device at the time of the hot press forming of the wooden board, the conventional forming board can be used. Compared to the method that is performed separately afterwards, the board heating process can be completely omitted, other attachment processes are greatly simplified, and separate large-scale equipment is not required. Has the advantage that it can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a process layout diagram showing an example of an apparatus used for carrying out a method of the present invention.

[Explanation of symbols]

 1 gas reservoir 2 small hole for mixed gas injection 3 pump for circulating mixed gas 4 homing machine 5 conveyor 6 steam injection press 7 press side conveyor 8.9 upper and lower press plates 8 '・ 9' upper and lower hot plates

Claims (1)

[Claims] 1. In the process of crushing or crushing and applying a thermosetting adhesive to a wood board material to form a mat, and heat-pressing the mat with a steam injection press, the mat is pressed and bonded. Reinforced wood, characterized by performing internal formalization at the same time as the board of wood board by injecting a mixed gas of formaldehyde source and sulfur dioxide from one surface of the board while the agent is heat-cured. Board manufacturing method.