# US 4,391,763 A · Process for the manufacture of halogen-containing resin particles of larger bulk density comprising mixing particles of the resin with inorganic salts, treated in a mixture in a gaseous phase and separating the inorganic salt from the product

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 4,391,763 A
- Document ID: US4391763A
- Status: Granted
- Kind: A
- Application number: 06/223,947
- Filed: 1981-01-12
- Granted: 1983-07-05
- Earliest claimed: 1980-01-11
- Assignees: Kureha Kagaku Kogyo Kabushiki Kaisha
- Inventors: Kunihiko Ueno; Akiyasu Ishii; Masazi Hukuda; Kazuyuki Nakayama
- Web page: https://patentgrep.com/patent/US4391763A

## CPC

- C08J 3/12: Powdering or granulating
- C08J 2327/00: Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Derivatives of such polymers
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)

## Abstract

This invention relates to a compactingly processing method for the manufacture of spherical particles, having a heavier apparent specific gravity, of halogen-containing ethylene resin. In this method, 100 wt. parts of particles of the resin are mixed with 20-500 wt. parts of one or more of heat-resisting inorganic salts having particle sizes of 0.01-50.mu.. This mixture is subjected to a heat treatment in a gaseous phase at a temperature higher than the melting point of the resin, and then, the once added inorganic salt or salts is/are separated from the heat-treated intermediate products. In this way, the resin particles are subjected to a substantial compacting and size reduction.

## Claims

### Claim 1

A process for the manufacture of spherical particles, having a heavier bulk specific gravity, of halogen-containing ethylene resin prepared from at least one monomer selected from vinylidene fluoride, vinyl fluoride, chlorotrifluoroethylene, trifluoroethylene, tetrafluoroethylene, vinylchloride, vinylidene chloride and vinyl bromide, said process comprising in combination of; a step of mixing 100 wt. parts of particles of the said resin with 20-500 wt. parts of one or more of the heat-resisting inorganic salts having particle sizes of 0.01-50 , which are in the form of stable particles at a temperature higher than the melting point of said halogen-containing ethylene resin; a step for heat-treating said mixture in a gaseous phase at a temperature higher than melting point of the said resin; and a further step for separating said inorganic salt or salts from the heat-treated intermediate products.

### Claim 2 (depends on 1)

The process of claim 1, wherein the halogen-containing ethylene resin is vinylidene fluoride resin.

### Claim 3 (depends on 1)

The process of claim 1, wherein the halogen-containing ethylene resin is vinyl chloride resin.