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

Patent metadata

Field	Value
Publication number	US-10604592-B2
Application number	US-201515302307-A
Country	US
Kind code	B2
Filing date	Apr 8, 2015
Priority date	Apr 9, 2014
Publication date	Mar 31, 2020
Grant date	Mar 31, 2020

Abstract

Provided is a dispersion stabilizer for suspension polymerization comprising an aqueous emulsion containing a dispersant (A), a dispersoid (B), a graft polymer (C), and an aqueous medium, wherein the dispersant (A) contains a surfactant, the dispersoid (B) contains a polymer having an ethylenically unsaturated monomer unit, the graft polymer (C) is obtained by graft polymerization of the ethylenically unsaturated monomer with the dispersant (A), a mass ratio [A/(A+B+C)] is 0.001 or more and less than 0.18, a mass ratio [C/(A+B+C)] is 0 or more and less than 0.04, and the total content of the dispersant (A), the dispersoid (B), and the graft polymer (C) is 35 to 70 mass %. A vinyl polymer to be obtained by suspension polymerization of a vinyl compound using the dispersion stabilizer has good plasticizer absorption. Further, the number of fish-eyes that occur when the vinyl polymer is formed is small, and the hue deterioration is also suppressed. Further, the dispersion stabilizer also has excellent handleability.

First claim

The invention claimed is:

1. A dispersion stabilizer for suspension polymerization comprising an aqueous emulsion comprising a dispersant (A), a dispersoid (B), a graft polymer (C), and an aqueous medium, wherein:
the dispersant (A) consists of a nonionic surfactant, a cationic surfactant, or an amphoteric surfactant,
wherein when the dispersant (A) is a nonionic surfactant, the nonionic surfactant is polyoxyethylene alkyl ether, polyoxyethylene sorbitan ester or glycerin ester,
the dispersoid (B) comprises a polymer comprising an ethylenically unsaturated monomer unit,
the graft polymer (C) is obtained by graft polymerization of the ethylenically unsaturated monomer with the dispersant (A),
a mass ratio [A/(A+B+C)] of the dispersant (A) with respect to a total amount of the dispersant (A), the dispersoid (B), and the graft polymer (C) is 0.001 or more and less than 0.18,
a mass ratio [C/(A+B+C)] of the graft polymer (C) with respect to the total amount of the dispersant (A), the dispersoid (B), and the graft polymer (C) is 0 or more and less than 0.04, and
a total content of the dispersant (A), the dispersoid (B), and the graft polymer (C) is 35 to 70 mass %.

2. The dispersion stabilizer according to claim 1 , wherein the dispersoid (B) comprises a polyvinyl ester.

3. The dispersion stabilizer according to claim 2 , wherein the polyvinyl ester is polyvinyl acetate.

4. The dispersion stabilizer according to claim 1 , wherein a weight-average molecular weight of a solid content in the aqueous emulsion as measured by gel permeation chromatography is 1,000,000 or less.

5. The dispersion stabilizer according to claim 1 , wherein the dispersant (A) comprises a nonionic surfactant or a cationic surfactant.

6. A method for producing the dispersion stabilizer according to claim 1 , the method comprising:
obtaining the aqueous emulsion by polymerization of 100 parts by mass of the ethylenically unsaturated monomer in the aqueous medium in the presence of 1 to 20 parts by mass of the dispersant (A).

7. The method according to claim 6 , wherein the aqueous emulsion is obtained by polymerization of the ethylenically unsaturated monomer in the presence of a chain transfer agent and the dispersant (A).

8. A method for producing a vinyl resin, the method comprising: performing suspension polymerization of a vinyl compound in an aqueous medium in the presence of the dispersion stabilizer according to claim 1 .

9. The method according to claim 8 , wherein a mass ratio of the vinyl compound with respect to the aqueous medium is 0.57 to 1.25.

Assignees

• Kuraray Co

Inventors

• Fukuhara Tadahito
• Kumaki Yosuke
• Michel Samuel
• Hartmann Dirk

Classifications

• C08F2/18

  Suspension polymerisation · CPC title

• C08F283/06

  on to polyethers, polyoxymethylenes or polyacetals {(C08F283/004 takes precedence)} · CPC title

• C08F2/30

  non-ionic · CPC title

• C08F2/20 Primary

  with the aid of macromolecular dispersing agents · CPC title

• C08F2/24

  with the aid of emulsifying agents · CPC title