JPH0623714A - Production of extremely thin fiberboard - Google Patents

Abstract

PURPOSE:To obtain an extremely thin fiberboard as the surface decorative material of furniture, a building material or living things generally produced from a wooden material such as plywood, particle board or a laminated material or the substitute material of a thin decorative substrate plate constituted of veneer heretofore. CONSTITUTION:2-3wt.% of a synthetic fiber with a length of 5-15mm is mixed with a wooden fiber obtained by a usual method to form a raw material fiber which is, in turn, coated with an adhesive in a state suspended in air streams. This coated fiber is formed into a mat with required thickness by a dry forming machine wherein agitators 5 are provided in a forming box 3 and this mat is thermally pressed and molded to produce an extremely thin fiberboard with a thickness of about 0.3-2.0mm by a usual method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention has a thickness of 0.3 mm-2.
Regarding the manufacturing method of ultra-thin fiber board of about 0 mm, plywood,
It is suitable for use as a surface makeup for furniture, building materials, household appliances, etc. made from wood materials such as particle board and laminated wood, or as a substitute material for a thin plate for makeup base that was conventionally composed of a single plate. .

[0002]

2. Description of the Related Art Wood materials such as plywood and particle boards, which are widely used for furniture, building materials, household appliances, etc., have to be subjected to makeup processing on their surfaces. Obtained by cutting the raw wood of 0.
It was common to utilize wood veneer with a thickness of 3 mm to 1.0 mm.

[0003]

However, the above-mentioned high-quality raw wood suitable for the above-mentioned wood veneer tends to be exhausted not only domestically but also abroad, and in view of the recent problems of forest protection, It is becoming difficult to secure these wood veneers both quantitatively and economically, and the fact is that the development of ultra-thin wood fiber boards to replace these veneers is being demanded from many directions.

Therefore, as a result of studying the manufacturability of the above-mentioned ultra-thin fiber board, the inventors of the present invention have found that the conventional fiber board-making technology does not technically solve the following problems.
It has turned out that it is impossible to economically manufacture a high-precision fiberboard having a thickness of 2.0 mm or less. That is, it prevents the spheroidization of the fibers due to the toughness of the adhesive applied to the wood fibers, does not cause variations in the planar weight distribution of the mat, and does not collapse when the thin mat is moved or handled. The point is to secure strength, etc.

[0005]

The present inventors have completed the present invention by earnestly conducting experimental research to solve the above three problems.

[0006] That is, a synthetic fiber having a length of 5 to 15 mm is contained in wood fiber obtained mainly by disintegrating sawdust and old wood.
% (Weight ratio) to make a raw material fiber, which is suspended in the air flow and coated with an adhesive, and then a mat of the required thickness is formed by a dry forming machine having an agitator in the forming box. The method of forming a hot-pressed plate by the method was used.

[0007]

According to the method of the present invention, the adhesive is applied in a state where the raw material fibers and the adhesive are suspended in the air flow, and then the air is continuously blown to the forming machine and scratched by the agitator provided in the forming box. Since it is designed to drop and accumulate on the forming wire in a mixed state, it is possible to prevent fibers coated with an adhesive from spheroidizing or from adhering to the machine wall and growing and mixing into the mat. You can
It has a special effect of obtaining a highly accurate mat that is uniform over the entire surface.

Further, by mixing a relatively long synthetic fiber in the raw material fiber, the mat strength can be sufficiently increased.

[0009]

EXAMPLES The construction of the present invention will be described in more detail below with reference to one example. Waste materials such as sawdust and old materials are made into chips, which are then made into fibers by a defibrating machine. After adjusting the water content by applying a thermosetting or thermoplastic adhesive to the mat, and forming a mat and then heat-pressing the mat, it is the same as the case of the fiber board by the dry method before. In the manufacturing method of the present invention, first, a polyester fiber having a length of 5 to 15 mm, preferably about 10 mm, is mixed in the above wood fiber in a weight ratio of 2 to 3% to obtain a raw material fiber.

This raw material fiber is introduced into a device (not shown) called an air flow blender, kept in a state of being suspended in the air flow, and an appropriate amount of urea resin adhesive is applied during this period, either directly or by a feeder. After being temporarily stored in an attached bean, etc., it is blown to the forming machine described below.

FIG. 1 shows an example of a forming machine. Reference numeral 1 is an air duct for raw material fibers coated with an adhesive, 2 is a shooter having a swing bar 2'in the vicinity of the inlet, and 3 is a shooter. The forming box is equipped with an agitator zone 5 having a large number of mixing blades 4 rotated by a motor (M) in its lower half, and the above raw material fibers fall onto a forming wire 6 which moves at a constant speed. -It was made to deposit.

Reference numeral 7 in the drawing denotes the forming wire 6 described above.
2 shows an air flow exhaust duct provided so as to face the lower surface of FIG.
Further, the relatively long synthetic resin fibers blended in the above raw material fibers have the purpose of increasing the strength of the mat by being entangled with other wood fibers, so if the length is 5 mm or less, the effect of entanglement is small. On the other hand, if the length exceeds 15 mm, the mixing property with other fibers is rather bad and the fibers tend to be spheroidized. Therefore, the range is set to 5 to 15 mm. Further, as the synthetic resin fiber, polypropylene or polyethylene fiber is suitable in addition to the polyester resin in the above example,
The adhesive is not limited to the above urea resin, and a thermosetting adhesive such as a melamine resin or a thermoplastic adhesive such as a vinyl acetate-based or synthetic rubber-based emulsion may be used.

As described above, in applying the adhesive to the raw material fibers, the adhesive is applied in a state where the fibers are suspended in the air flow by using an air flow blender.
The raw material fibers are prevented from spheroidizing, adhering to the machine wall, and growing, and are further blown into a forming machine and fed into the agitator zone 5, where the fibers are uniformly dropped onto the forming wire 6 while stirring, By depositing, it is possible to improve the accuracy of forming, that is, to minimize the variation in planar weight of the mat.

The desired ultra-thin fiber board was manufactured by pressing the thus obtained mat under the same heating and pressing conditions as in the general fiber board forming step.

[0015]

As described in detail above, since the ultrathin fiberboard of the present invention is formed by molding wood fibers, it has excellent surface smoothness as compared with the conventional wood veneer, and has excellent cutting, painting and makeup. It has a good surface finish such as paper sticking, and it has no physical orientation of fibers like wood veneer made from natural wood, its physical strength is stable, and it expands and contracts due to moisture absorption and desorption. However, since there is no directionality, the product subjected to surface treatment (makeup) does not cause warping, rolling or cracking, and the dimensional stability is excellent.

Regarding the above-mentioned dimensional stability, the maximum dimensional change rate (100-percentage of the maximum change amount with respect to the original length of the plate) due to the change in the water content of the conventional lauan veneer and the ultrathin fiber plate of the present invention
Is as shown in Table 1.

[Table 1]

In order to support the above-mentioned characteristic effects of the present invention, ordinary lauan synthesis is used, and the surface veneer is replaced with the ultrathin fiber board obtained by the method of the present invention. Table 2 shows the results of the accelerated cracking test on each surface of the decorative plywood bonded with the system adhesive.

[Table 2]

In the cracking test, three types of decorative veneer are used: cherry tree, oak tree, and pine tree, exposed to an atmosphere of 50 ° C. and 90% relative humidity for 6 hours, and then 50 ° C. The number of cracks generated in the decorative veneer was measured after exposing each sample for 16 hours in an atmosphere of 30% humidity and repeating 7 times for each sample.

In addition, since the ultrathin fiber board according to the present invention is a thermocompression molded product, a so-called bedrock layer is formed under the front and back surfaces, and the surface hardness is so hard that a floor material, etc., which is particularly required to have hardness, is used. The result is that the heel mark test has a significant advantage over the surface of ordinary lauan plywood, and the product quality peculiar to the fiberboard has very little variation. Many excellent effects can be expected, such as easy design and processing.

[Brief description of drawings]

FIG. 1 is a central sectional view showing an example of a forming machine used for carrying out the present invention.

[Explanation of symbols]

 1 Raw material fiber air duct 2 Shooter 3 Forming box 4 Scraping blade 5 Agitator zone 6 Forming wire 7 Air flow exhaust duct

Claims (1)

[Claims] 1. A wood fiber obtained by a conventional method, having a length of 5 to 15 mm.
2 to 3% (weight ratio) of the synthetic fiber of the above is used as a raw material fiber, and the adhesive is applied in a state of being suspended in an air flow. Then, a dry forming machine having an agitator in a forming box is used to obtain a required thickness. After forming the mat,
A method for producing ultra-thin fiberboard, which is characterized by hot-pressing by a conventional method.