JPH0458809B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing fine powder of polyolefin resin at low cost. (Prior Art) Powders of polyethylene, polypropylene, etc. are widely used as coating materials, and the particle size range most in demand is 10μ to 60μ. Therefore, improvements in the dissolution method are aimed at efficiently producing shaped particles within these particle size ranges, and there has been a desire to discover a solvent with good production efficiency, including the solvent recovery process. (Objective of the Invention) An object of the present invention is to provide a method for producing spherical particles of a polyolefin resin having a particle size within the above-mentioned particle size range with good yield, easy solvent recovery, and no need for washing the produced particles with water. (Solution Means and Features of the Present Invention) As a result of researching various water-soluble low-boiling point solvents that can achieve these objectives, the present inventor developed a mixed solvent of diethylethanolamine (Amino Alcohol 2A manufactured by Nippon Nyukazai Co., Ltd.) and xylene. was found to be effective. This solvent has the advantage that it is easy to recover and does not require washing the product particles with water. (Structure of the Invention) The mixed solvent in the present invention is a mixed solvent of 6 to 8 parts by volume of diethylethanolamine and 4 to 2 parts by volume of xylene. In particular, a mixing ratio of 7:3 is the most efficient. Add not more than 40 parts by weight of the polyolefin resin to 100 parts by volume of this mixed solvent, stir and dissolve while heating to approximately 140°C in a non-oxidizing atmosphere, then stop stirring and slowly cool the resin. Fine particles are precipitated during the cooling process. The generated particles are filtered and dried under vacuum (70° to 90°C,
5 to 40 mmHg) and then classified into products. Example 1 Put 30 kg of mixed solvent and 1.5 kg of polypropylene resin into a pressurized dissolution tank, fill it with nitrogen gas, and raise the pressure to 1.
Kg/cm ² and heated to 140° C. with stirring. After about 2 hours, the solution was completely dissolved, so heating and stirring were stopped, and water cooling was performed. Particles precipitated at about 70°C, and the mixture was further cooled to 40°C. Thereafter, the mixture was stirred again for 20 minutes and the particles were filtered off using a filter press. The recovered particles were placed in a heated vacuum dryer at 80° C. with a degree of vacuum of 10 mmHg and dried to obtain a product. The particle size distribution of the product particles was as shown in the table. Example 2 1.5 kg of polyethylene was melted and cooled under the same conditions as in Example 1. In this case, particles precipitated at about 80°C. Thereafter, a product was obtained in the same manner. The particle size distribution was as shown in the table.

【table】

[Table] Note that the resin concentration in the above examples is about 5%, but by increasing this concentration, the average particle size becomes larger, so it is possible to adjust the particle size using this property.

Claims (1)

[Claims] 1 In a container equipped with a stirring and heating device,
After dissolving 1 to 40 parts by weight of a polyolefin resin in 100 parts by volume of a mixed solvent of diethylethanolamine and xylene under pressure and heating in a non-oxidizing atmosphere, heating and stirring were stopped and the mixture was gradually cooled. A method for producing fine polyolefin resin powder, which comprises precipitating fine polyolefin resin powder.