JPH10235717A - Extrusion pressure controller and method for extrusion-molding wood plastic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology which can do molding relatively easily while improving a wood feel in the technology of molding wood plastic. SOLUTION: In the extrusion molding of wood plastic in which wood powder is mixed with a resin, to control extrusion pressure applied to a resin material, after the melting of the material and before the feeding of the material to a mold, the molding is done to increase the pressure stepwise and discontinuously. For example, an extrusion pressure controller in which the passage of the resin is formed to narrow stepwise and discontinuously toward the side of the mold is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for extruding a wooden plaque having a woody appearance, and more particularly, to a pressure regulator for adjusting an extrusion pressure during extrusion of a wooden plaque, and to perform pressure adjustment. It concerns the manufacturing method.

[0002]

2. Description of the Related Art Various techniques have been provided for producing a molded product called a so-called wood plastic by mixing natural wood powder (wood flour) with a resin. P from it
CTJP94 / 00351 (International publication number; WO94
/ 20280) "cellulose-based fine powder,
The technology of "wood-like molded articles and wood-like products" will be briefly described.

A powder obtained by pulverizing a cellulose material as a raw material is subjected to a grinding treatment to obtain powder particles having an increased bulk specific gravity, and the outer peripheral surface of the powder particles has a surface particle smaller in diameter and harder than the powder particles. Are fixed to form fixed particles, and the resin and the pigment are mixed and melted in the fixed particles, and thereafter or simultaneously with the melting, formed into a desired shape by extrusion molding or injection molding. Then, it is possible to provide a method of manufacturing a wood-like product and a wood-like product having a pattern very close to the grain of a natural tree on the surface and having a feeling such as a touch feeling similar to that of a natural tree.

[0004]

However, there has been a problem that there is no established technique regarding the wood texture of the molded article in the above-mentioned molding technique of wood plastic. This will be described in more detail. One of the conditions for determining the woody texture is the degree of mixing of the wood powder (crushed powder of cellulose material, “fixed grains” in PCTJP94 / 00351) with the resin. That is, the higher the mixing ratio of the wood powder (fixed grains) with the resin, the more the woody feel is obtained. On the other hand, if the mixing ratio is high, the molding itself may be difficult, for example, it may take a long time to knead the resin, or a molding failure may easily occur.

The problem to be solved by the present invention is to provide a technique for forming a wooden plaque that can be formed relatively easily while enhancing the woody feel. Here, an object of the present invention described in claim 1 is to provide an extrusion pressure regulator that contributes to relatively easy molding while enhancing the feeling of wood. It is another object of the present invention to provide a method for extruding a wooden plastic that can be formed relatively easily while enhancing the woody feel.

[0006]

SUMMARY OF THE INVENTION The present invention is to achieve the above object. (1) The extrusion pressure regulator according to the above (1), wherein the extrusion pressure applied to the resin material after the resin material is melted and before being sent to the mold in the extrusion molding of the wood plastic in which the wood powder is mixed with the resin. , Wherein the passage of the resin material is formed so as to gradually and discontinuously narrow toward the mold side.

(Definition of terms) "Resin" is a resin suitable for extrusion molding of wood plastics, including hard resins and soft resins, for example, vinyl chloride resin, foamed vinyl chloride resin, polyethylene resin, polypropylene resin , Phenol resin, urethane resin, polyurethane resin, ABS resin, polystyrene resin and the like. It is determined by the function and use of the final molded product.

[0008] "Wood flour" may be ground powder of rice straw, bacas, etc. in addition to ground powder of natural wood and its sawdust. Further, it is assumed that the wood powder specified in claim 3 is included.
The “stepwise and discontinuous” configuration refers to, for example, a configuration that is formed in a step shape in a cross-sectional shape in the extrusion direction.
The stage is determined from various conditions such as the properties of the resin material and the type of the final molded product. If the number of steps is too large, the discontinuity approaches continuous, so that an appropriate number of steps is selected for the surface desired for the molded article.

(Operation) The operation of the extrusion pressure regulator according to the first aspect will be described. When the melted resin material is fed into the extrusion pressure regulator, the passage becomes a resistance at a portion formed so as to gradually and discontinuously become narrower, the pressure increases, and the kneading of the resin material proceeds. . Also, the resin is rubbed against the inner wall of the extrusion pressure regulator and remains there. As a result, the wood powder contained in the resin material relatively floats near the surface of the mold. Therefore, it is possible to provide a molded article having a high woody feel for the content of the wood flour. In other words, since the content of the wood flour is small, it is possible to reduce troubles such as defective molding which are likely to occur when the content of the wood flour is large. According to a second aspect of the present invention, in the extrusion molding of a wood plastic in which wood powder is mixed with a resin, after the resin material is melted and before being sent to a mold, the extrusion pressure applied to the resin material is gradually increased. It is a method for extruding a wooden plastic, which is discontinuously increased. (Claim 3) The method for extruding a wooden plastic according to claim 3 is as follows.
The method for extruding a wooden plastic according to claim 2 is technically limited, and the “wood flour” used in the method for extruding a wooden plastic according to claim 2 is a powder obtained by grinding. The method is characterized in that surface particles smaller in diameter and harder than the particles are fixed to the outer peripheral surface of the particles.

[0010] In addition, pigments are often included in order to make the wood closer to real wood. The “pigment” is a colored pigment, for example, an inorganic or organic pigment such as iron oxide, cadmium yellow, or carbon black. (Definition of terms) The method of “fixing surface particles having a smaller diameter and harder than the particles on the surface of the particles” includes, for example, crushing by a ball mill and long-term high-speed stirring by a high-speed rotating blade type mixer. There is a method. The treatment for removing the fluff of the cellulosic fibers may be performed separately from the fixing of the surface grains.

"Surface grains" include metals and metal compounds such as titanium oxide, ferrite, aluminum, nickel, silver and calcium carbonate, and nonmetals such as ceramics. (Action) When the wood flour is limited as in claim 3, a molded product having a feeling closer to a real wood than a normal wood plastic can be obtained.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to embodiments and drawings. The drawing used here is FIG. FIG. 1 is a conceptual diagram of the present invention.
First, the configuration of this embodiment will be described. The extrusion pressure adjuster described in this embodiment adjusts the extrusion pressure applied to the resin material after the resin material is melted and before being sent to a mold in the extrusion molding of wood plastic in which wood powder is mixed with resin. An extrusion pressure regulator, wherein a passage of a resin material is formed so as to gradually and discontinuously narrow toward a mold side.

Here, the resin material will be described in detail. “Resin” is a resin suitable for extrusion molding of wood plastic, and in this embodiment, is a vinyl chloride resin. Also,
The "wood flour" mixed with the resin is obtained by further crushing the sawdust into finely ground powder, and on the outer peripheral surface of the powder,
Surface particles smaller in diameter and harder than the powder particles were fixed. In addition to such a resin and wood flour, a pigment is contained to form a pellet in advance to obtain a wood-like pellet.
By changing the kind of pigment, plural kinds of wood-like pellets are prepared. The plurality of types of wood-like pellets are melted and mixed, and then sent to the above-mentioned extrusion pressure regulator before being sent to the mold.

[0014] The molten resin material is extruded from a cylinder having a diameter of 50 mm. This extrusion pressure regulator is made of iron, has a cross-section in the extrusion direction formed in a two-step shape, an inner diameter on the cylinder side of 30 mm, an inner diameter on the mold side of 25 mm, and a length in the extrusion direction. It is 100 mm. In addition, between the cylinder and the extrusion pressure regulator, a member for adjusting the flow of the resin called a “core” is often installed. The core is
Since the flow condition may be fine-tuned after installation,
In general, brass is used so that cutting can be easily performed.

When the melted resin material is fed into the extrusion pressure regulator, the pressure increases due to resistance in the path where the resin material is formed so as to gradually and discontinuously become narrower, and the resin material is mixed. Refining proceeds. Also, the resin is rubbed against the inner wall of the extrusion pressure regulator and remains there. As a result, the wood powder contained in the resin material relatively floats near the surface of the mold. Therefore, it is possible to provide a molded article having a high woody feel for the content of the wood flour. In other words,
Since the content of the wood flour is small, it is possible to reduce troubles such as molding defects which are likely to occur when the content of the wood flour is large.

Further, since the wood flour is limited as described above, a molded article having a feeling closer to a real wood than a normal wood plastic can be obtained. Extrusion pressure regulators and cores can be used.

[0017]

According to the first aspect of the present invention, it is possible to provide an extrusion pressure regulator which contributes to relatively easy molding while improving the feeling of wood. Further, according to the second and third aspects of the present invention, it is possible to provide a method for extruding a wooden plastic that can be formed relatively easily while enhancing the feeling of wood.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of the present invention.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Jun Taniguchi 2-4-5 Takaido East, Suginami-ku, Tokyo Inside Misawa Homes Co., Ltd. (72) Inventor Kenji Ogawa 2-4-5 East Takaido, Suginami-ku, Tokyo Misawa Home Co., Ltd. (72) Inventor Yoshinori Nakano 2-45-5 Takaido Higashi, Suginami-ku, Tokyo Misawa Home Co., Ltd. (72) Yoshiaki Kobayashi 2-4.5 Takaido Higashi, Suginami-ku, Tokyo Misawa Home (72) Inventor Masami Kato 2-4-5 Takaido Higashi, Suginami-ku, Tokyo Misawa Homes Co., Ltd.

Claims (3)

[Claims] In an extrusion molding of a wood plastic in which wood powder is mixed with a resin, after melting a resin material and before sending it to a mold,
An extrusion pressure regulator for adjusting an extrusion pressure applied to a resin material, wherein a passage of the resin material is formed so as to be gradually and discontinuously narrowed toward a mold side. . 2. In the extrusion molding of wood plastic in which wood powder is mixed with resin, after melting the resin material and before sending it to a mold,
A method for extruding a wood plastic, wherein the extrusion pressure applied to the resin material is increased stepwise and discontinuously. 3. The powdered wood according to claim 1, wherein the powdered wood is obtained by grinding the powder, and the surface of the powder is fixed on the outer peripheral surface of the powder, which is smaller in diameter and harder than the powder. 2. The method of extrusion molding of wood plastic.