JPS62149727A - Composite plastic particle and its production - Google Patents

Abstract

PURPOSE:To obtain the titled particles excellent in heat resistance, by coating the surfaces of plastic particles with fine particles of a simple substance, alloy or compound of a (semi-)metal. CONSTITUTION:Plastic particles (A) (e.g., ethylene/vinyl acetate copolymer particles) are mixed with 0.1-50wt% ultrafine particles (B) selected from among a simple substance of a metal (e.g., Ni) or of a semi-metal (e.g., silicon), an alloy of a (semi-)metal (e.g., Fe/Ni alloy) or its compound such as an oxide (e.g., TiO), nitride (e.g., Si3N4) and carbide (e.g., WC), each of which has a particle diameter of 1mum or below, preferably, of 0.01-1mum and is 1/10-1/100 of that of component A to form a composite layer of component B uniformly adhered and the fixed to the surface of component A. If desired, this procedure is repeated to form composite particles of an at least bilayer structure.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to plastic composite particles that improve the functions of various plastics and expand their uses, and a method for producing the same.

(Prior art and its problems) When conventional plastic particles are thermally sprayed as a mixture with ceramic powder, for example, the plastic and ceramic tend to be separated and unevenly distributed due to the difference in the particles, which makes it difficult to obtain a uniform coating film. The problem was that it was difficult to obtain.

(Means for Solving the Problems) This invention not only solves the above problems by making plastic composite particles whose surfaces are coated with ultrafine ceramic particles, but also uses other materials instead of ceramics. It was discovered that if ultrafine particles of this material were similarly applied to the particle surface of plastic, new properties could be added to the plastic and its functions could be improved.

Therefore, the purpose of this invention is to change the properties of conventional plastics by modifying the surface of plastic particles, improve their functions, solve various problems in conventional fields of use, and create new The aim is to expand its uses.

(Structure of the invention) Next, details of this invention will be explained.

First, the plastic particles used as a starting material in this invention are, for example, polyethylene.

Thermoplastic resins such as polypropylene, ethylene/vinyl acetate copolymer, polyvinyl chloride, polystyrene, polyethylene terephthalate, polyamide, methacrylic resin,
Further, examples include particles of thermosetting resins such as epoxy, phenol, polyurethane, and melamine resin alone or in a mixture of two or more thereof.

On the other hand, the ultrafine particles coated in a layer on the surface of these plastic particles have a particle size of 1 μm or less, preferably 0.01 μm or less.
~1 μm, which is 1 μm of the particle size of plastic particles.
/10 to 1/100 is desirable, and the materials include iron, cobalt, nickel, palladium, platinum, chromium, molybdenum, titanium, zirconium, copper, zinc,
metals such as aluminum, silver, manganese, and silicon;
Single metalloids such as boron, alloys of these metals and semimetals such as iron/nickel, silver/palladium, and cobalt/chromium alloys, as well as titanium oxide, silicon oxide, aluminum oxide, zirconium oxide, etc. oxide.

Examples include nitrides such as titanium nitride, silicon nitride, and zirconium nitride, and carbides such as silicon carbide, tungsten carbide, and titanium carbide. These may be used alone or as a mixture of two or more.

This composite particle shape is achieved by simply mixing these ultrafine particles with the aforementioned plastic particles, preferably in a weight proportion of 0.1 to 50%. At this time, the ultrafine particles mentioned above have extremely high surface activity, so the frictional electrification and frictional heat generated during mixing act as triggers, and they are uniformly and firmly attached and fixed to the surface of the plastic particles, forming a composite layer. .

This surface coating layer can be formed into composite particles having a multilayer structure of two or more layers by repeating this operation as necessary.

Example 1 Based on 100 parts by weight of true spherical powder (average particle size 5 μm) of 5P-500 (manufactured by Toshisha Co., Ltd., nylon 12).

Ultrafine particles of titanium nitride (manufactured by Tokyo Steel, average particle size 0.05
20 parts by weight (μm) were added and mixed for 6 hours in a ball mill. The results of measuring the physical properties of the plastic particles before treatment and the composite particles obtained are shown in Table 1, and electron micrographs of both are shown in FIG.

Table 1: When 1 g each of the samples before and after treatment was added to 10 cc of water, stirred, and left to stand, the samples before treatment separated from the water and floated to the surface, but the samples after treatment were uniformly dispersed in the water.

Example 2 Based on 100 parts by weight of powder (average particle size 150 μm) of ethylene/vinyl acetate copolymer (manufactured by Bayer AG).

Ultrafine silicon carbide particles (manufactured by Tokyo Steel, average particle size 0.08
2.5 parts by weight (μm) was added and mixed for 2 hours in a ball mill.

Ethylene vinyl acetate copolymer (EV
When a mixture of powder A) and silicon carbide powder was sprayed onto a steel plate using a gas flame spraying device for plastic powder, the spray nozzle was clogged, resulting in poor workability.
VA powder and silicon carbide powder were separated and unevenly distributed, making it impossible to obtain a uniform coating film. However, when thermal spraying was performed using silicon carbide composite particles of ethylene vinyl acetate copolymer obtained by the above method, there was no problem with workability during thermal spraying, and a uniform and smooth composite coating was obtained. Obtained.

Example 3 Ultrafine nickel metal particles (average particle size 0.07 μm) were added to 100 parts by weight of polyethylene powder (average particle size 100 μm).
A mixture was prepared in the same manner as in Example 1 by adding 10 parts by weight.

The sample after treatment had improved dispersibility and hydrophilicity compared to the sample before treatment.

Example 4 Polyethylene terephthalate powder (average particle size 18,
, jihahaha-1;1. 14 i > kika ζ)
10 parts by weight of ate (average particle size 0.05 μm) were added and mixed and prepared in the same manner as in Example 1.

It was found that the sample after treatment had improved dispersibility and hydrophilicity compared to the sample before treatment.

Example 5 Example 1 was prepared by adding 5 parts by weight of ultrafine particles (average particle size 0.1 μm) of a low melting point metal (metal name: tin) with a melting point of 232°C to 100 parts by weight of nylon powder (average particle size 5 μm). Composite particles were obtained by mixing and preparing in the same manner as above. In addition, ceramic ultrafine particles (compound name: silicon carbide, average particle size 0)
．． 05 μm) was added and mixed in the same manner to obtain composite metallic microcapsules, which were found to have excellent dispersibility.

(Effects of the Invention) As described above, the composite particles of the present invention can be produced by appropriately selecting the type of plastic particles as the starting raw material and the type of material for the coating ultrafine particles. improve durability, abrasion resistance, or weather resistance.

It has the effect of imparting adhesiveness, hydrophilicity, or special functions to plastic particles, and improving the handling of ultrafine particles, so it is useful for thermal spraying materials, pigments, paints, various plastic molding materials, pharmaceutical binders, catalyst carriers, It can be widely used in fields of application such as magnetic materials.

[Brief explanation of drawings]

FIGS. 1(a, b) are electron micrographs showing the state of particles before and after treatment when nylon 12 powder is treated with ultrafine particles of titanium nitride to form a composite.

Claims (1)

[Claims] 1) The surface of the plastic particles is coated with 1 μm or less in particle size.
Plastic composite particles coated with one or more layers of ultrafine particles of a single metal, alloy, or compound of two or more metals or semimetals. 2) By mixing ultrafine particles of one or more metals or semimetals, alloys, or compounds with a particle size of 1 μm or less into plastic particles, the ultrafine particles can be layered on the surface of the plastic particles by their surface activity. 1. A method for producing composite plastic particles, which comprises adhering and fixing the particles to a plastic composite particle, and repeating this process as necessary.