Process for producing fluorinated polymer having ion-exchange groups

• US 4,298,699 A
• Filed: 02/07/1980
• Issued: 11/03/1981
• Est. Priority Date: 02/07/1980
• Status: Expired due to Term

• Current Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Original Assignee: Asahi Glass Company, Limited (AGC, Inc.)
• Inventors: Yamashita, Masami, Sugaya, Yoshio, Miyake, Haruhisa, Asawa, Tatsuro
• Primary Examiner(s): Hamrock, William F.
• Assistant Examiner(s): Kulkosky, Peter F.
• Application Number:
  US06/119,521
• Time in Patent Office: 635 Days
• Field of Search: 521/27, 521/31
• US Class Current: 521/31
• CPC Class Codes: C08F 20/00 Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
• CPC Class Codes: C08F 214/18 Monomers containing fluorine
• CPC Class Codes: C08F 214/184 with fluorinated vinyl ethers

Abstract

A fluorinated copolymer having ion-exchange group is produced by copolymerizing a fluorinated ethylenic unsaturated monomer and a functional monomer having a functional group of carboxylic acid group or a group which can be converted to carboxylic acid group in an aqueous medium in the presence of a polymerization initiator source. The fluorinated copolymer obtained by the copolymerization is treated with an alcohol at higher than 20° C. in the form of particles before a molding. The melt flowability of the fluorinated copolymer is improved.

Claims

1. A process for producing a fluorinated copolymer having ion-exchange groups, comprising:

copolymerizing a fluorinated ethylenic unsaturated monomer and a monomer having a carboxylic acid group or group convertible to a carboxylic acid group in an aqueous solution in the presence of a polymerization initiator;

treating the particles of copolymer product obtained with an alcohol at a temperature greater than 20°

C.; and

drying said alcohol treated particles, thereby substantially removing said alcohol from said particles.

2. The process according to claim 1, wherein the fluorinated copolymer is granular and said alcohol treatment is conducted by stirring said granular copolymer in a large amount of an alcohol at an elevated temperature.

3. The process according to claim 1, wherein said alcohol treatment is conducted by incorporating a small amount of an acid in an alcohol.

4. The process according to claim 1, wherein the functional monomer is a fluorovinyl compound having the formula

5. The process according to claim 1, wherein the fluorinated ethylenic unsaturated monomer is a fluorinated olefin having the formula

6. The process according to claim 4, wherein the fluorovinyl compound is a compound having the formula ##STR3## wherein p is 0 or 1;

l is 0 or 1;

m is 0 to 1;

n is 0 to 8;

A represents --COF or --COOR₁ and R₁ represents a lower alkyl group.

7. The process according to claim 5, wherein the fluorinated ethylenic unsaturated monomer is tetrafluoroethylene.

8. The process according to claim 1 or 2 wherein said alcohol is a C₁ -C₅ lower alcohol.

9. The process according to claim 1 wherein the time period for the alcohol treatment is in the range of 1 to 50 hours.

10. The process according to claim 1 or 2 wherein said alcohol is used in an amount of more than 100 ml. per 100 g. of the fluorinated copolymer.

11. The process according to claim 3 wherein the acid is incorporated in an amount of 1 to 5 wt. parts per 100 wt. parts of the fluorinated copolymer.