JPH08131875A - Production of pulverized powder - Google Patents

Abstract

PURPOSE: To efficiently regulate pulverized powder formed by pulverizing cellulosic materials to a specific grain size or below and to improve the yield of this pulverized powder by improving a technique for pulverizing the cellulosic materials and a technique for sieving the grain sizes after pulverization. CONSTITUTION: The cellulosic materials are subjected to rough primary pulverizing and the primarily pulverized materials subjected to the primary pulverizing is subjected to secondary pulverizing. The secondarily pulverized materials subjected to the secondary pulverizing are subjected to sieving. The materials selected by this sieving are formed as the pulverized powder. The materials which are not selected by the sieving are again subjected to the secondary pulverizing.

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 pulverized powder obtained by pulverizing a cellulosic material.

[0002]

2. Description of the Related Art As a technique related to the present invention, a PC
T JP94 / 00351 (International Publication Number; WO94
/ 20280) "Cellulose-based fine powder particles,
The technology of "wood-like molded products and wood-like products" will be briefly described. The pulverized powder obtained by pulverizing the cellulose material as a raw material is ground to obtain powder particles having an increased bulk specific gravity, and fixed on the outer peripheral surface of the powder particles, surface particles having a smaller diameter and a hardness smaller than the powder particles. Fixed particles are obtained by mixing the resin and the pigment with the fixed particles, melting the fixed particles, and thereafter or simultaneously with melting, forming into a desired shape by extrusion molding or injection molding. Then, it is possible to provide a method for producing a wood-like product and a wood-like product which have a pattern extremely close to the grain of a natural tree on the surface and have a texture such as a touch feeling similar to that of the natural tree.

[0003]

However, in the prior art, means for efficiently forming pulverized powder having a particle size of a certain size or less by pulverizing a cellulosic material has not been established. . That is, the poor yield of pulverized powder caused by immaturity of the technique of pulverizing a cellulosic material or the technique of sieving the grain size after pulverization has been a problem.

The problem to be solved by the present invention is to improve the technique for pulverizing a cellulosic material and the technique for sieving the particle size after pulverization to obtain a pulverized powder obtained by pulverizing a cellulosic material. The object is to efficiently reduce the particle size to a certain value or less and improve the yield of pulverized powder. Here, the object of the invention of claim 1 is to improve the technique of pulverizing a cellulosic material, so that the pulverized powder obtained by pulverizing a cellulosic material can be efficiently reduced to a certain particle size or less. It is to provide a method for producing crushed powder.

The object of the invention described in claims 2 and 3 is to pulverize a cellulosic material by improving the technique for pulverizing the cellulosic material and the technique for sieving the particle size after pulverization. It is an object of the present invention to provide a method for producing pulverized powder, which is capable of efficiently reducing the size of the pulverized powder to a predetermined particle size or less.

[0006]

The present invention is to achieve the above-mentioned object. The method for producing pulverized powder according to claim 1, wherein the cellulosic material is roughly primary pulverized, the primary pulverized material after the primary pulverization is subjected to the secondary pulverization, and the secondary pulverization is completed. A method for producing a crushed powder, characterized by subjecting the next crushed material to sieving, making the crushed powder selected by the sieving, and again subjecting those not selected by sieving to secondary crushing. Is.

Here, the "cellulosic material" is wood, rice straw, bacas, or the like. The method for producing crushed powder according to claim 2 is a technical limitation of the method for producing crushed powder according to claim 1, and the sieving is performed using an air classifier. Here, the "wind force classifier" is a device that separates a particle group based on a particle size and a density based on an equilibrium condition of gravity, inertial force or centrifugal force and gas resistance, and is also called a cyclone classifier.

The method for producing the pulverized powder according to claim 3 is a technical limitation of the method for producing the pulverized powder according to claim 1, and the sieving uses a mesh of at most 500 μm square. It is characterized by using a vibrating screener. It should be noted that the mesh of 500 μm square at the largest used here is usually about 300 μm square, but it is more preferably 150 μm or less.

[0009]

[Operation] The method for producing pulverized powder according to claim 1,
It operates as follows. The cellulosic material becomes a primary pulverized material which is pulverized to some extent by the primary pulverization.
The primary crushed material becomes a secondary crushed material having a size to be crushed powder by the secondary crushing.

The powder selected by sieving from the secondary crushed material becomes crushed powder. Those not selected are subjected to secondary crushing again, and become secondary crushed materials. Since the secondary pulverized material is subjected to sieving, the material selected by sieving from that is pulverized powder. The operation of the pulverized powder manufacturing method described in claim 2 is the same as the above-mentioned operation except that the sieving is performed by the air classifier.

The operation of the method for producing crushed powder according to claim 3 is the same except that the sieving is performed by a vibrating screener using a mesh of at most 500 μm square.
It is similar to the above operation. The finished crushed powder is 5
It means that the crushing is performed so that it can pass through the mesh of 00 μm square.

[0012]

Embodiments of the present invention will now be described with reference to the embodiments and the drawings.
This will be described in more detail. The drawings used here are FIGS. 1 and 2. FIG. 1 is a conceptual diagram showing a first embodiment of an apparatus for realizing the pulverized powder manufacturing method according to the present invention. FIG. 2 is a conceptual diagram showing a second embodiment of the apparatus for realizing the pulverized powder manufacturing method according to the present invention.

First, a first embodiment will be described with reference to FIG. This embodiment is a manufacturing method using a wind power classifier and corresponds to the invention of claim 2. Also, FIG.
In the figure, the process up to the production of fixed particles by adding a further step to the manufactured pulverized powder is illustrated. First, a cellulosic material (“cellulose material” in FIG. 1) is subjected to primary pulverization. As the cellulosic material, a few millimeters to a few centimeters are used, which usually include knots and foreign substances. A cutter mill was used in this example as an apparatus for performing primary pulverization. By this primary pulverization, the cellulosic material is pulverized to several millimeters or less, and becomes the primary pulverized material.

Then, the primary pulverized material is subjected to secondary pulverization. In this example, a stone mill was used as the device for secondary pulverization. By this secondary pulverization, the primary pulverized material becomes the secondary pulverized material pulverized to 1 mm or less. Next, the secondary pulverized material is classified. By this classification, those having an average particle size of 5 μm or less are further classified as a separate use product A used as a separate use from the final fixed particles produced in this example. In addition, a powder having an average particle size of 60 μm is crushed powder. Furthermore, even if the average particle size is about 30 μm, which is neither a separate-use product A nor a pulverized powder, it is more preferable as a separate-use product B used as a separate use from the final fixed particles produced in this example. Divide. The usage of the different-use product A or the different-use product B enables painting with a wood texture, for example, by mixing with the paint.

If the average particle size is about 150 to 300 μm or more, which is neither a different-use product A nor a different-use product B, and is not a crushed powder, it is returned to the secondary crusher and the secondary crushing is performed again. . Next, surface particles, for example, surface particles of titanium oxide are mixed with this pulverized powder and subjected to a grinding treatment to prepare fixed particles. This grinding treatment is performed by a ball mill using ceramic balls, for example.

Next, in order to remove apparently defective products from the fixed grains produced by this grinding treatment, a mesh of about 6 mm square (shown as "# 4" in FIG. 1). "4" means the number of meshes existing in 1 inch), and in some cases, it is sieved by a vibrating screener using a mesh of about 8 mm square. The apparent defective products include crushed powder that has aggregated for some reason, as well as fragments of ceramic balls and the like.

After sieving the defective products, the first sieving is carried out by a vibrating sieving machine using a mesh of 300 μm square (denoted as “# 50” in FIG. 1). Even if it does not pass through this mesh, it will be a fixed-grain finished product as a "mesh-over product". However, with respect to the quality of the molded product made of the fixed particles, the extrusion performance is slightly lower than that of the fixed particles produced by the second embodiment.

On the other hand, the material that has passed through this mesh is subjected to a second sieving with a vibration sieving machine which also uses a mesh of 300 μm square. Those that did not pass through this mesh are treated the same as the fixed-grain finished product. The product that has passed through the second mesh is used as a "finished product" to manufacture a wood-like product that requires higher precision and a higher sense of quality than a normal finished product. The second sieving performed here may not be performed in some cases.

Next, a second embodiment will be described with reference to FIG. This embodiment is a manufacturing method using a vibrating screener and corresponds to the invention of claim 3. Also, FIG.
In the figure, the process up to the production of fixed particles by adding a further step to the produced pulverized powder is also illustrated. First, the procedure until the cellulosic material is subjected to the primary pulverization and the secondary pulverization is the same as that of the first embodiment, and the description thereof will be omitted.

Next, the secondary crushed material is sieved by a vibration sieving machine using a mesh of 300 μm square. Those that did not pass this mesh are
Return to the secondary crusher and perform secondary crushing again. On the other hand, those that pass through this mesh become pulverized powder. Next, surface particles, for example, surface particles of titanium oxide, are mixed with this pulverized powder and subjected to a grinding treatment to prepare fixed particles. In order to remove apparently defective products from the prepared fixed particles, approximately 6 mm square The sieving is carried out by a vibrating sieving machine using the above mesh, but the steps are the same as those in the first embodiment, and therefore the description thereof is omitted.

After sieving defective products, sieving is performed with a vibration sieving machine using a mesh of 300 μm square. What passed through this mesh is a fixed-grain finished product. On the other hand, those that do not pass through this mesh contain large particles and are used as fixed particles for use such as products in which particles are visible in the final molded product. In addition, if the quality of the secondary crushed material is good by using a device that performs secondary crushing with high crushing ability or by spending more time than usual on the secondary crushed material, The mesh used in the vibrating screener for sieving and the mesh used in the vibrating screener for sieving after the grinding treatment are 150 μm square. This improves the quality of the fixed-grain finished product and reduces the proportion of fixed-grain used for other purposes.

[0022]

According to the first aspect of the present invention, by improving the technique for pulverizing the cellulosic material, the pulverized powder obtained by pulverizing the cellulosic material can be efficiently reduced to a certain particle size or less. It was possible to provide a method for producing pulverized powder capable of Further, according to the inventions of claims 2 and 3, by improving the technique of pulverizing the cellulosic material and the technique of sieving the particle size after pulverization, the cellulosic material is pulverized. It was possible to provide a method for producing a crushed powder that can efficiently reduce the crushed powder to a certain particle size or less.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a first embodiment of an apparatus that realizes a pulverized powder manufacturing method according to the present invention.

FIG. 2 is a conceptual diagram showing a second embodiment of the apparatus for realizing the pulverized powder manufacturing method according to the present invention.

Claims (3)

[Claims] 1. A rough primary pulverization of a cellulosic material, a secondary pulverization of a primary pulverized material after the primary pulverization, and a sieving of a secondary pulverized material after the secondary pulverization. And a pulverized powder selected by sieving, and secondary pulverization is again performed on the powder not selected by sieving. 2. The method for producing pulverized powder according to claim 1, wherein the sieving is carried out by using an air classifier. 3. The method for producing pulverized powder according to claim 1, wherein the sieving is carried out by using a vibrating screener having a mesh of at most 500 μm square.