JPH03186386A - Powder processing - Google Patents

Abstract

PURPOSE:To clean powder completely by allowing powder to come in contact with fibrillary fiber and flocculating powder in the fibrillary fiber. CONSTITUTION:Powder is flocculated in fibrillary fiber by allowing the former to come in contact with the latter. In this case, the material for the fibrillary fiber is not particularly defined but any type of the fiber is acceptable regardless of the material, organic or inorganic. For example, the fiber may be made pulp, cellulose fiber, polyamide polymer, polyester polymer, polyolefin polymer, acrylic polymer, vinyl chloride or vinylidene chloride polymer, polyvinyl alcohol polymer or asbestos.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for processing powder.

[Conventional technology]

In the process of pulverizing a substance, for example, in pulverizing an acrylonitrile polymer, when switching the type of polymer, it is necessary to completely remove the polymer powder remaining in the pulverizer. In this case, there is a method of cleaning the inside of the pulverizer with compressed air to remove the remaining powder, but this method has the problem that the polymer powder scatters and pollutes the environment. Furthermore,
This method using compressed air has the disadvantage that powder adhering to the recesses in the pulverizer cannot be completely removed.

Furthermore, during work such as grinding or polishing materials, powder of the material to be ground or polished is generated, and there is a problem of contamination of the floor surface due to the scattering of the powder. Cleaning of such contamination is generally carried out by methods such as suction removal with a vacuum cleaner, removal with water or a cleaning agent, and the like. However, these methods cannot be called excellent methods because they cause powder to fly into the air and require secondary treatment such as waste water treatment.

Under these circumstances, a dust treatment method using a fibrillating polytetrafluoroethylene resin is known (Japanese Patent Laid-Open No. 81832/1983).

In this method, first, a fibrillating polytetrafluoroethylene resin and two substances that react with each other to generate reaction heat, such as a combination of quicklime and water, are mixed with dust-generating powder, and the reaction heat is After the temperature of the mixture is raised by , the polytetrafluoroethylene resin is fibrillated by compression-shearing action. This is a dustproof treatment method for dust-producing powder, in which the fibrillated resin traps the dust-producing powder.

The disadvantage of this method is that the two react with each other and generate reaction heat.
The temperature of the polytetrafluoroethylene resin must be increased by the heat of reaction, and the mixture of this resin and the dust-generating substance must be subjected to compression-shearing action. It is something that must be given. The need to mix materials other than polytetrafluoroethylene resin and apply compression-shearing effects is not only complicated to operate, but also restricts the conditions and scope of use, making it difficult to use for general purposes. isn't it.

Under these circumstances, there is a demand for a simple and effective method for removing powder, but no excellent method has been found so far.

(Problems to be Solved by the Invention) In view of the above-mentioned current situation, the present invention provides a method by which powder can be easily removed with a simple operation.

[Means to solve the problem]

The present inventors have completed the present invention by discovering that fibrillated fibers have the ability to aggregate powder as a result of repeated research to solve the above problems.

That is, the present invention is a powder processing method characterized by bringing the powder into contact with fibrillated fibers and agglomerating the powder onto the fibrillated fibers.

Hereinafter, the powder processing method of the present invention will be explained in more detail.

The powder processing method of the present invention is characterized by using fibrillated fibers that have the ability to aggregate powder.

The fibrillated fiber used in the present invention is a fiber in which a large number of fine whisker-like filaments branching from the above-mentioned fibers are generated on the surface of the main fiber.

Figure 1 is an electron micrograph (100x magnification) showing the structure of fibrillated fibers made of acrylonitrile polymer used in Example 1.As can be seen from Figure 1, fibrillated fibers have thick trunks. On the surface of the fibers, many fine whisker-like filaments branching from the above-mentioned trunk occur. In addition, it was observed that the fibers forming the trunk were partially split and separated into a plurality of finer fibers.

Figure 2 is an electron micrograph (100x magnification) showing the structure of fibrillated fibers made of aromatic polyamide.Similar to the fibrillated fibers shown in Figure 1, the surface of the thick trunk fiber has branches extending from the trunk. Many fine, separated whisker-like filaments occur.

The fibrillated fibers used in the present invention are not particularly limited in material, and may be either organic or inorganic fibers, such as wood, cellulose fibers, polyamide polymers, polyester polymers, and polyolefin polymers. These fibers are made of acrylic polymers, vinyl chloride or vinylidene chloride polymers, polyvinyl alcohol polymers, asbestos, and the like.

When the fibrillated fiber used in the present invention is made from wood, valves commonly used in the paper industry and for boat fishing can be used.

When cotton or various synthetic fibers are used as raw materials, they can be produced by beating these fibers using a machine such as a beater or refiner used in the paper industry.

When producing fibrillated fibers for use in the present invention from synthetic fibers, it is more preferable to use fibers with a structure that more easily produces whisker-like filaments by beating with the beater or refiner. Synthetic fibers with filaments are preferably fibers having many independent or continuous pores, especially fibers in which the pores have a large number of openings of unspecified shapes in the cross section of the fiber, and A fiber in which the above-mentioned openings form a linear (straw-shaped) void having a length of 60 μm or more and substantially parallel to the longitudinal direction of the fiber inside the fiber is excellent. This fiber can be produced by mixing a polymer, at least one of which is fiber-forming, with another polymer, spinning the mixture to form a fiber, and then extracting and removing the other polymer.

To explain the above fiber using an acrylic polymer as an example, a conventionally known polymer containing acrylonitrile as the main component and a random or block combination of ethylene oxide and propylene oxide with a number average molecular weight of 500 to 50,000 are used. It can be manufactured by aging a spinning dope containing a polymer, spinning it, and then performing normal fiber manufacturing processes such as washing with water and stretching.

The diameter of the fibrillated fibers used in the present invention is 20 denier or less for thick trunk fibers, preferably 10 denier or less, more preferably 5 denier or less, and for whisker-like fibers branched from the above, 1 Denier or less, preferably 0.17' denier or less, more preferably 0
．． 05 denier or less. The reason for this is that the finer the fibers, the more effective they are in aggregating powder. Furthermore,
An excellent feature of the fibrillated fiber of the present invention is that it has a fiber portion that becomes a thick trunk. In the case of ultrafine fibers consisting of whisker-like filaments, the filaments appear in the state of fine dust, causing problems in handling.

Next, the method of agglomerating powder into fibrillated fibers according to the present invention involves mixing fibrillated fibers with powder and stirring, or using an aggregate of fibrillated fibers, such as a non-woven fabric, to disperse powder. This can be done by wiping or other means.

〔Example〕

The present invention will be explained below with reference to Examples.

Example 1 Acrylonitrile 95.0%, methyl acrylate 4.5%
% and sodium methallylsulfonate 0.5% (% is superimposed)
A copolymer consisting of a polyethylene oxide-polypropylene oxide-polyethylene oxide block polyether (number average molecular weight 10,000, ratio of polyethylene oxide and polypropylene oxide 70:30) was dissolved in dimethylformamide, and an acrylic-based polyether was dissolved in dimethylformamide. 23% copolymer, block polyether 2.
A 3% spinning stock solution was prepared. This spinning stock solution was allowed to stand still for 6 hours, then extruded through a spinneret into a coagulation bath with a temperature of 35°C and a dimethylformamide concentration of 75%, washed with water, stretched 12 times in boiling water, and dried in hot air at 80°C. 1.
A 5d fiber was produced.

Observation of an electron micrograph (4000x magnification) of a longitudinal cross-section cut in the longitudinal direction of the fiber revealed that the fiber was in the form of a striation having a length of 60 parts or more that was approximately parallel to the longitudinal direction of the fiber. It was found that the material had voids of the shape (shape). Also, from a similar photograph of the cross section, the shape of the opening of the void is approximately circular;
It was found that they had unspecified shapes, such as flat shapes, repeated sharp bends at the edges, large cross-sections, and small cross-sections, and that a large number of these shapes were irregularly mixed together.

The above fibers were cut into 15-pieces, 10 parts of the fibers were mixed with 90 parts of water, and the fiber dispersion was then mixed with a disc gap of 0.
Processed with a papermaking disc refiner adjusted to 1-
It was beaten to a freeness of 450 cc.

Electron micrograph of the fiber obtained by this treatment (10
0x) is shown in Figure 1.

This fibrillated acrylic fiber log was put into a small pulverizer used for pulverizing acrylonitrile polymer and a household mixer (Kenko Denki Sangyo ■, product name MX-M3).
Stir for 1 minute. The acrylonitrile polymer remaining in the container aggregated and adhered to the fibrillated acrylic fibers, and the container was completely washed.

In particular, powder adhering to the back side of the stirring blade and remaining in the gap between the stirring blade and the bottom of the container could not be easily removed due to the lack of an appropriate cleaning method in the past. According to this method, it was possible to remove it extremely easily and completely.

Example 2 The same operation as in Example 1 was carried out, except that 10 g of a generally commercially available fibrillated aromatic boria ξ-do fiber (Fig. 2) was used.

As a result, as in Example 1, it was confirmed that the acrylonitrile polymer powder remaining in the container could be completely removed.

Example 3 Using a wood valve as a beater commonly used in the paper industry
A dry fibrillated wood pulp was produced by beating with water, followed by washing with water, dehydration, and drying.

10 g of this fibrillated wood pulp was processed using a pulverizer similar to that used in Example 1 used for pulverizing an acrylonitrile polymer (
The mixture was poured into a household ξ mixer and stirred for 1 minute.

The acrylonitrile polymer powder remaining in the mill was aggregated into fibrillated wood pulp, and the mill was thoroughly cleaned. In particular, the powder adhering to areas that are difficult to clean using normal methods, such as the gap between the stirring blades and the gap between the stirring blade and the bottom of the container, was completely removed as in Example 1, and the fibrils were completely removed. It was confirmed that the treated wood pulp has excellent powder aggregation ability.

〔Effect of the invention〕

According to the present invention, for example, the powder of acrylonitrile polymer remaining in the crusher can be completely washed by simply introducing the fibrillated fibers into a container and stirring the container. It is particularly effective for cleaning powder remaining on the back side of the stirring blade and the gap between the stirring blade and the bottom of the crusher.

As described above, by utilizing the present invention, powder can be completely removed with a simple operation.

[Brief explanation of drawings]

Figure 1 is an electron micrograph (100x magnification) of the structure of the fibrillated acrylic fiber used in Example 1, and Figure 2 is an electron micrograph of the structure of the fibrillated aromatic boria ξ-do fiber used in Example 2. (100 times).

Claims (1)

[Claims] 1. A powder processing method characterized by bringing the powder into contact with fibrillated fibers and agglomerating the powder onto the fibrillated fibers.