JPH0516109A - Manufacture of fiber molded form - Google Patents

Abstract

PURPOSE:To uniformly mix water and a powdery adhesive and to disperse this mixture into ligneous fiber by separating both the solid component of the adhesive and water necessary for producing the solution thereof and allowing a fine granular polyacrylate-based polymer to absorb this water and controlling the adhesive property of water and simultaneously making the solid component of the adhesive powdery. CONSTITUTION:Starch powder is selected as a powdery adhesive and added to a polyacrylate-based polymer which contains large amount of water and is made fine granular. This mixture is agitated and mixed. Starch powder 4 is stuck on the whole circumferential surface of polymer granules and thereafter these are uniformly mixed and dispersed into ligneous fiber 3 by using compressed air. This mixture is intruded into a molded form made of glass fiber reinforced plastics by using compressed air and thereafter this molded form is irradiated with microwave to generate steam from water absorbed in the polymer granules. Starch is gelatinized by this steam. Furthermore ligneous fiber 3 is bonded with each other by drying the gelatinized starch and strength of the molded form 1 is exhibited.

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 low density wood fiber molding.

[0002]

2. Description of the Related Art As a method for producing a low-density wood fiber molded body, a water-solvent adhesive is made into a snow-like shape, the adhesiveness of the adhesive is removed, and then this is squeezed into wood fibers using compressed air. There is a method of uniformly mixing and dispersing (Japanese Patent Application No. 3-1023).
82). However, if the snow-like adhesive melts, the adhesive becomes tacky, making it difficult to uniformly mix and disperse and mold it. It should always be cooled until the end. In addition, because microwaves are not easily absorbed by ice, it is necessary to mix a small amount of substances such as salt that easily absorb microwaves into the snow-like adhesive so that the temperature of the snow-like adhesive rises rapidly. Which complicates the manufacturing process.

[0003]

The problem to be solved is that when an adhesive containing water as a solvent is made into a snow-like shape, it melts when the temperature returns to room temperature and has adhesiveness. This is the point that a small amount of substances such as salts that easily absorb microwaves must be mixed. The present invention provides a technique for producing a low-density wood fiber molded body, and its manufacturing method must be simple and inexpensive. Therefore, a method capable of molding at room temperature is advantageous. For this purpose, it is necessary that the adhesive agent using water as a solvent does not have stickiness even at room temperature and is uniformly dispersed in the wood fiber.

[0004]

In order to achieve the above object, in the present invention, a solid component of an adhesive and water necessary for the solution thereof are separated, and water is added to a fine particle polyacrylate polymer. By absorbing the water and suppressing the adhesion of water, the solid component of the adhesive is powdered so that water and the powdered adhesive can be uniformly mixed and dispersed in the wood fiber by using compressed air. To do. After pushing this mixture into various molds using compressed air, microwave heating is performed, because water is present as a liquid in the polymer particles,
The microwave will be rapidly absorbed by the water.

Further, by attaching a powdery adhesive agent to the entire surface of a polyacrylic acid type polymer which contains a large amount of water and is in the form of fine particles, the adhesion of water contained in the polymer particles can be improved. Are eliminated to improve the uniform mixing property of the polymer particles and the wood fiber.

[0006]

[Function] Since there is little adhesion between the polyacrylate type polymer which contains a large amount of water and is in the form of fine particles, and the powdery adhesive does not have tackiness, these are dried by compressed air. It is easily and uniformly dispersed in the wood fiber.
Therefore, water can be uniformly dispersed in the wood fiber at room temperature, and as a result, the water necessary for gelatinization can be supplied to the powdery adhesive that is uniformly dispersed in the wood fiber. At this time, if a powdery adhesive is preliminarily attached to the entire surface around the polymer particles, the adhesiveness of the polymer particles disappears, and the uniform mixing of the polymer particles and the wood fiber is improved. Since water can be efficiently supplied to the powdery adhesive, the amount of water mixed in the wood fiber can be reduced, which leads to a reduction in drying time and cost. If the mixture is microwave heated, the microwaves are selectively absorbed by the water present in the polymer particles. As a result, a large amount of water vapor is generated from the water, and the water vapor causes the powdery adhesive to be gelatinized, and the gelatinized adhesive is dried to allow the wood fibers to be bonded to each other, resulting in the strength of the molded body. Is exhibited, and a low-density wood fiber molding excellent in strength characteristics can be obtained within a short time. At this time, since hydrogen bonds are generated between the hydrophilic groups present in the polyacrylic acid salt-based polymer and the wood fibers, the strength of the molded body can be expected to be improved as compared with the case of using the adhesive alone.

[0007]

Embodiments will be described with reference to the drawings. Inexpensive starch powder is selected as a powdery adhesive agent, and this is added to a polyacrylate polymer that contains a large amount of water and is in the form of fine particles, and the mixture is stirred and mixed to form a polymer particle of the polymer particles. After adhering the starch powder all over the periphery, it is uniformly mixed and dispersed in the wood fiber using compressed air.
This mixture was pressed into a glass fiber reinforced plastic molding die of a predetermined shape using compressed air, then irradiated with microwaves to generate water vapor from the water absorbed in the polymer particles, The steam gelatinizes the starch. Further, by drying the gelatinized starch, the wood fibers are adhered to each other, and the strength of the wood fiber molded body is developed.

If it is desired to omit the step of adhering the starch powder to the entire surface of the polymer particles, first, the starch powder is uniformly mixed and dispersed in the wood fiber by using compressed air, and then the polymer is added thereto. The particles are uniformly mixed and dispersed. When the starch powder is uniformly mixed and dispersed in the wood fiber by using compressed air, if the starch powder is scattered and difficult to mix, the polymer particles are first mixed and dispersed in the wood fiber, and then By uniformly mixing and dispersing the starch powder, the starch powder adheres to the surface of the polymer particles, and thus the scattering can be prevented. Alternatively, the wood fiber, the polymer particles and the starch powder may be uniformly mixed and dispersed at the same time by using compressed air.

The starch powder may be either unprocessed starch or processed starch. As the powdery adhesive agent, in addition to starch powder, those using water as a solvent such as gelatin and polyvinyl alcohol can be used. As an alternative to the wood fiber, recycled pulp from waste paper or the like can be used.

[0010]

As described above, the present invention can form a low-density and uniform wood fiber molding having excellent strength characteristics in a short time, and thus the following effects are brought about. At room temperature, water and a powdery adhesive can be uniformly mixed and dispersed in the wood fiber. Further, since the water exists in a liquid state, the microwave is selectively absorbed by the water without adding a substance that improves the absorption of the microwave to the water. Therefore, the manufacturing of the wood fiber molded body is simplified, and as a result, the manufacturing cost can be reduced.

Since the polyacrylic acid type polymer and the wood fiber are adhered to each other, it can be expected that the strength of the molded product is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state in which starch acrylate is adhered to the entire surface of a polyacrylic acid-based polymer in the form of fine particles containing a large amount of water and wood fibers are uniformly mixed and dispersed in a molding die. It is a figure.

FIG. 2 is a cross-sectional view showing a state in which starch powder is attached to the entire periphery of the polymer particles.

[Explanation of symbols]

1 Mold 2 Hole 3 Wood fiber 4 Polyacrylic acid-based polymer that contains a large amount of water and becomes fine particles 5 Starch powder adheres to one surface around the polymer 5 Poly that contains a large amount of water and becomes fine particles Acrylate-based polymer-6 starch powder

Claims (2)

[Claims] 1. A polyacrylic acid-based polymer which is a fine particle containing a large amount of water in a dried wood fiber.
Powdered adhesive containing water and water as a solvent is added, and these are uniformly mixed and dispersed using compressed air, then molded into various shapes, and heated in this state by microwave heating for a short time. Manufacturing method to get the body. 2. A powdery adhesive agent containing water as a solvent is preliminarily adhered to the entire periphery of a polyacrylate polymer which is in the form of fine particles containing a large amount of water, and the adhesion between the polymer particles. The method for producing a fiber molded body according to claim 1, wherein after extinguishing the property, this is uniformly mixed and dispersed in the dried wood fiber using compressed air.