# US 5,349,008 A · Process for suspension polymerization of vinyl compound

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- Number: US 5,349,008 A
- Document ID: US5349008A
- Status: Granted
- Kind: A
- Application number: 07/778,125
- Filed: 1991-12-04
- Granted: 1994-09-20
- Earliest claimed: 1990-04-05
- Assignees: Kuraray Co., Ltd.
- Inventors: Shigeki Takada; Ken Yuki; Hitoshi Maruyama; Taku Tanaka; Kazunari Igarashi
- Web page: https://patentgrep.com/patent/US5349008A

## CPC

- C08F 2/20: with the aid of macromolecular dispersing agents
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS

## Abstract

Disclosed herein is a process for suspension polymerization of a vinyl polymer which comprises using as the suspending agent a polyvinyl ester polymer having an ionic group at an end thereof or a polyvinyl alcohol polymer having a degree of hydrolysis of 90 mol % or less which is obtained by hydrolysis of the above polyvinyl ester polymer. According to the above-mentioned process, vinyl polymer granules having a sharp granulometric dispersion, high bulk density, high plasticizer absorption and low vinyl monomer residue are obtained.

## Claims

### Claim 1

A process for suspension polymerization of vinyl chloride which comprises using as the secondary suspending agent a self-emulsifiable vinyl ester polymer having an ionic group at an end thereof or a self-emulsifiable vinyl alcohol polymer having a degree of hydrolysis of 60 mol % or less which is obtained by hydrolysis of said vinyl ester polymer, said ionic group being selected from the group consisting of amino group, ammonium group, carboxyl group and sulfonic group.

### Claim 2 (depends on 1)

The process for suspension polymerization of vinyl chloride according to claim 1, wherein said secondary suspending agent is a self-emulsifiable vinyl alcohol polymer having a degree of hydrolysis of 10 to 60 mol % and a degree of polymerization of 50 to 3,000.

### Claim 3 (depends on 1)

The process for suspension polymerization of vinyl chloride according to claim 1, wherein said secondary suspending agent is an aqueous dispersion containing as the dispersoid a self-emulsifiable vinyl ester polymer having an ionic group at an end thereof or a self-emulsifiable vinyl alcohol polymer having a degree of hydrolysis of 60 mol % or less which is obtained by hydrolysis of said vinyl ester polymer, said ionic group being selected from the group consisting of amino group, ammonium group, carboxyl group and sulfonic group.

### Claim 4 (depends on 1, 2, 3)

A process for suspension polymerization of vinyl chloride which comprises using a suspending agent containing the secondary suspending agent as set forth in any one of claims 1 to 3 in a proportion by solid weight of 10 to 70%.

### Claim 5 (depends on 4)

The process for suspension polymerization of vinyl chloride according to claim 4, wherein (A) the secondary suspending agent as set forth in claim 4 and (B) a polyvinyl alcohol having a degree of hydrolysis of 62 to 90 mol % and a degree of polymerization of 300 to 3,000 are used in combination in a (A)/(B) ratio by solid weight of 1/9 to 7/3.

### Claim 6

A secondary suspending agent for suspension polymerization of vinyl chloride which comprises a self-emulsifiable vinyl ester polymer having an ionic group at an end thereof or a self-emulsifiable vinyl alcohol polymer having a degree of hydrolysis of 60 mol % or less which is obtained by hydrolysis of said vinyl ester polymer, said ionic group being selected from the group consisting of amino group, ammonium group, carboxyl group and sulfonic group.

### Claim 7

A secondary suspending agent for suspension polymerization of vinyl chloride which comprises an aqueous dispersion containing as the dispersoid a self-emulsifiable vinyl ester polymer having an ionic group at an end thereof or a self-emulsifiable vinyl alcohol polymer having a degree of hydrolysis of 60 mol % or less which is obtained by hydrolysis of said vinyl ester polymer, said ionic group being selected from the group consisting of amino group, ammonium group, carboxyl group and sulfonic group.

### Claim 8

An aqueous dispersion which comprises water as the dispersion-medium and as the dispersoid a self-emulsifiable vinyl ester polymer having an ionic group at an end thereof or a self-emulsifiable vinyl alcohol polymer having a degree of hydrolysis of 60 mol % or less which is obtained by hydrolysis of said vinyl ester polymer, said ionic group being selected from the group consisting of amino group, ammonium group, carboxyl group and sulfonic group.

### Claim 9

A self-emulsifiable vinyl alcohol polymer having a carboxylic group at an end thereof, a degree of hydrolysis of 10 to 60 mol % and a degree of polymerization of 50 to 3,000.