JP2745469B2 - Manufacturing method of ultra-thin fiberboard - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the present invention, which has a thickness of 0.3 mm.
Regarding the production method of ultra-thin fiberboard of about 0 mm, generally plywood,
It is suitable for use as a surface decoration for furniture, building materials, living rooms, etc. made from wood materials such as particle boards and glued laminated wood, or as a substitute for a thin veneer base plate that has been conventionally made of a single veneer. .

[0002]

2. Description of the Related Art Wood materials such as plywood and particleboard, which are frequently used for furniture, building materials, living equipment, etc., must be subjected to decorative processing on the surface. 0 obtained by cutting raw wood.
It was common to use 3 mm to 1.0 mm thick wood veneers.

[0003]

However, high-quality logs suitable for the above-mentioned wood veneers tend to be gradually depleted not only in Japan but also abroad, and in view of the recent problems of forest protection, etc. 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 in place of these veneers has been demanded from various perspectives.

The inventors of the present invention have studied the possibility of producing the above-mentioned ultra-thin fiberboard, and as a result, the conventional fiberboard-making technology has the following problems unless technically solved.
It has been found that it is impossible to economically produce a high-precision fiberboard having a thickness of 2.0 mm or less. A mat that does not collapse when the thin mat is moved or handled, because it prevents spheroidization of the fiber due to the tackiness of the adhesive applied to the wood fibers, does not cause variations in the planar weight distribution of the mat. Points to ensure strength, etc.

[0005]

Means for Solving the Problems The present inventors diligently conducted experimental studies to solve the above three problems and completed the present invention.

That is, a synthetic fiber having a length of 5 to 15 mm is added to a wooden fiber obtained by defibrating mainly sawdust or old timber.
% (Weight ratio) to obtain a raw material fiber, which is floated in an air stream, coated with an adhesive, and formed into a mat having a required thickness by a dry forming machine having an agitator in a forming box. A means of hot pressing 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 fiber and the adhesive are floating in the air current, and then the air is continuously blown to the forming machine and scraped by the agitator provided in the forming box. Because it is made to fall and accumulate on the forming wire in a mixed state, the fiber coated with the adhesive is prevented from spheroidizing and from adhering and growing on the machine wall and mixing into the mat Can,
It has a special effect that a uniform mat with high accuracy can be obtained over the entire surface.

[0008] In addition, the fact that a relatively long synthetic fiber is blended in the raw material fiber has an effect that the mat strength can be sufficiently increased.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of the present invention will be described below in more detail with reference to one embodiment. In particular, waste materials such as sawdust and old materials are made into chips, which are further made into fibers by a defibrating machine. After adjusting the moisture content by applying a thermosetting or thermoplastic adhesive to the mat, it is a mat, and it is the same as the case of the fiber board by the conventional dry method, such as hot-pressing the mat. In the production method of the present invention, first, a polyester fiber having a length of 5 to 15 mm, preferably about 10 mm is blended with the above-mentioned wood fiber by 2 to 3% by weight to obtain a raw material fiber.

[0010] This raw material fiber is supplied to an air flow blender (JP-B-4).
No. 692 ), while maintaining a state of being suspended in an air stream, an appropriate amount of urea resin adhesive is applied during this time, and this is directly or a bean with a feeder or the like. After being temporarily stored, the air is blown to the forming machine described below.

FIG. 1 shows an example of a forming machine. Reference numeral 1 denotes an air duct for raw material fibers coated with an adhesive, 2 denotes a shooter having a swing bar 2 'near an inlet, and 3 denotes a shooter. The forming box is provided with an agitator zone 5 in the lower half of which is provided with a large number of mixing blades 4 which are rotated by a motor (M). The raw material fiber falls on a forming wire 6 which moves at a constant speed.・ It is made to accumulate.

In the figure, reference numeral 7 denotes the forming wire 6;
2 shows an air flow exhaust duct provided on the lower surface of the air flow.
In addition, the relatively long synthetic resin fiber blended in the raw material fiber has the purpose of increasing the strength of the mat by being entangled with other wood fibers, so that the effect of entanglement is thin when the length is 5 mm or less. On the other hand, if the length exceeds 15 mm, the miscibility with other fibers is rather poor, which tends to cause spheroidization of the fibers. Further, as the synthetic resin fiber, in addition to the polyester resin of the above example, polypropylene and polyethylene fibers are suitable,
The adhesive is not limited to the urea resin, but may be a thermosetting adhesive such as a melamine resin or a thermoplastic adhesive such as a vinyl acetate-based or synthetic rubber-based emulsion.

As described above, in applying the adhesive to the raw fibers, the adhesive is applied in a state where the fibers are suspended in the airflow using an airflow blender.
Prevent spheroidization of the raw material fiber, adhesion to the machine wall, and growth. Further, this is blown into a forming machine and sent to the agitator zone 5 where the fiber is uniformly dropped on the forming wire 6 while stirring. By depositing, it is possible to increase the precision of forming, that is, to minimize variations in the planar weight of the mat.

The mat thus obtained was pressed under the same heating and pressing conditions as in the ordinary fiberboard forming process to produce the desired ultrathin fiberboard.

[0015]

As described in detail above, the ultra-thin fiberboard of the present invention is formed of wood fiber, so that it has excellent surface smoothness as compared with conventional wood veneer, cutting, painting, and makeup. Good surface finish, such as sticking paper, and has no fiber directionality as with wood veneer obtained from natural wood, stable physical strength, and expansion and contraction due to moisture absorption and desorption. Since there is no directionality, there is no warping, twisting or cracking of the product subjected to the surface treatment (makeup), and the dimensional stability is very good.

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

[Table 1]

In order to support the above-mentioned characteristic effects in the present invention, ordinary Rawan synthesis and a veneer obtained by substituting an ultra-thin fiberboard obtained by the method of the present invention for a veneer of a tree type are used. Table 2 shows the results of an accelerated cracking test on each surface of the decorative plywood bonded with the system adhesive.

[Table 2]

In the cracking test, three types of veneer were used: cherry, oak, and pine. After being exposed to an atmosphere at a temperature of 50 ° C. and a relative humidity of 90% for 6 hours, the temperature was further increased to 50 ° C. After exposing for 16 hours in an atmosphere of 30% humidity and repeating 7 times for each sample, the number of cracks generated in the decorative veneer was measured.

In addition, since the ultra-thin fiberboard according to the present invention is a hot-pressed product, a so-called bedrock layer is formed under the front and back surfaces, and the surface height is high. Table
It is highly useful as a face material.In this case, the heel mark test results have a remarkable advantage over the surface of ordinary Rawan plywood, and there is very little variation in the properties of the product unique to fiberboard. Many excellent effects can be expected, such as easy design and processing.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Winding duct of raw fiber 2 Shooter 3 Forming box 4 Mixing blade 5 Agitator zone 6 Forming wire 7 Air flow exhaust duct

Claims (1)

(57) [Claims] 1. A fibrous wood fiber having a length of 5 to 15 m.
m to 2% (weight ratio) were mixed to obtain raw fibers, which were applied to an air flow blender to apply an adhesive, and a mat having a required thickness was formed by a dry forming machine having an agitator in a forming box. rear,
A method for producing an ultra-thin fiberboard, comprising hot-pressing and forming a fiberboard having a thickness of 0.3 to 2.0 mm according to a conventional method.