Dispersion stabilizer for suspension polymerization, and manufacturing method for vinyl resin

Patent metadata

Field	Value
Publication number	US-9777080-B2
Application number	US-201314415329-A
Country	US
Kind code	B2
Filing date	Jul 17, 2013
Priority date	Jul 19, 2012
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A dispersion stabilizer for suspension polymerization of vinyl compounds comprising a vinyl alcohol polymer (A) which has a saponification degree of 30 mol % or more and less than 60 mol % and a viscosity-average polymerization degree (P) of more than 200 and less than 600, and has a terminal alkyl group having 6 to 18 carbon atoms, and in which a content of monomer units having an oxyalkylene group is 0.3 mol % or less and the relationship between the viscosity-average polymerization degree (P) and a modification rate (S) (mol %) of the alkyl group satisfies Formula (1). Thus, there can be provided a dispersion stabilizer for suspension polymerization with which, during suspension polymerization of vinyl compounds including vinyl chloride, even when it is used in a small amount, the absorbency of a plasticizer is high, resulting in easy processing and formation of coarse particles is little and the remaining monomer components can be easily removed.

50≦ S×P /1.880<100  (1)

First claim

The invention claimed is:

1. A solution or dispersion, comprising:
a dispersion stabilizer; and
methanol or a compound (C) of formula (I)

wherein R 1 , R 2 and R 5 represent, independently of each other, a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R 3 represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a hydroxyalkyl group having 1 to 6 carbon atoms; R 4 represents a hydrogen atom, a hydroxyl group or an alkoxyl group having 1 to 6 carbon atoms; n represents an integer of 1 to 6,
wherein a content of methanol or the compound (C) in the solution or dispersion is 1 to 50% by mass, and
wherein the dispersion stabilizer comprises:
a vinyl alcohol polymer (A) which has a saponification degree of 35 mol % or more and less than 60 mol % and a viscosity-average polymerization degree (P) of more than 200 and 400 or less, and has a terminal alkyl group having 6 to 18 carbon atoms,
wherein a content of monomer units having an oxyalkylene group is 0.3 mol % or less and the relationship between the viscosity-average polymerization degree (P) and a modification rate (S)(mol %) of the alkyl group satisfies Formula (1):
50 ≦S×P/ 1.880<100  (1); and

a vinyl alcohol polymer (B) having a saponification degree of 65 mol % or more and a viscosity-average polymerization degree of 600 or more, wherein a mass ratio between the vinyl alcohol polymer (A) and the vinyl alcohol polymer (B) (A/B) is 10/90 to 55/45.

2. The solution or dispersion of claim 1 , wherein a block character of the residual vinyl ester groups in the vinyl alcohol polymer (A) is 0.6 or less.

3. The solution or dispersion of claim 1 , wherein the terminal alkyl group has 8 to 15 carbon atoms.

4. The solution or dispersion of claim 1 , wherein the terminal alkyl group is a straight-chain alkyl group or a branched alkyl group.

5. A method for manufacturing a vinyl resin, comprising conducting suspension-polymerization of vinyl compounds in the presence of the solution or dispersion of claim 1 .

6. The method of claim 5 , comprising:
charging a pre-prepared solution or dispersion comprising the dispersion stabilizer and methanol or a compound (C) of formula (I) in a reactor; and then
initiating suspension polymerization:

wherein
R 1 , R 2 and R 5 represent, independently of each other, a hydrogen atom or an alkyl group having 1 to 6 carbon atoms;
R 3 represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a hydroxyalkyl group having 1 to 6 carbon atoms;
R 4 represents a hydrogen atom, a hydroxyl group or an alkoxyl group having 1 to 6 carbon atoms; and
n represents an integer of 1 to 6.

7. The method of claim 5 , wherein the suspension polymerization is conducted at a temperature of 60° C. or higher.

Assignees

• Kuraray Co

Inventors

• Fukuhara Tadahito
• Kumaki Yousuke

Classifications

• C08L29/04

  Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids · CPC title

• C08F8/12

  Hydrolysis · CPC title

• C08F14/06 Primary

  Vinyl chloride · CPC title

• C08F2/38

  Polymerisation using regulators, e.g. chain terminating agents {, e.g. telomerisation} · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title