# US 4,397,980 A · Process for preparing PTFE powdered resins containing pigments employing ammonium carbonate or ammonium bicarbonate

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- Number: US 4,397,980 A
- Document ID: US4397980A
- Status: Granted
- Kind: A
- Application number: 06/419,545
- Filed: 1982-09-17
- Granted: 1983-08-09
- Earliest claimed: 1982-09-17
- Assignees: E. I. Du Pont de Nemours and Company
- Inventors: Theodore G. Tsakumis
- Web page: https://patentgrep.com/patent/US4397980A

## CPC

- C08J 3/212: {and solid additives}
- C08J 3/22: using masterbatch techniques
- C08J 2327/18: Homopolymers or copolymers of tetrafluoroethylene
- 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

Process for uniformly incorporating pigment into fine powder TFE polymers by premixing pigment and ammonium carbonate or bicarbonate, and then adding the mixture to a TFE polymer aqueous dispersion, followed by coagulating the pigment and TFE polymer.

## Claims

### Claim 1

Process for preparing tetrafluoroethylene (TFE) polymer resins having pigment dispersed therein, which comprises
a. mixing a pigment with ammonium carbonate or ammonium bicarbonate or both in a proportion of at least 40% by weight carbonate or bicarbonate,
b. adding the mixture to an aqueous dispersion containing 10-30% by weight of a non-melt-processible TFE polymer,
c. coagulating the TFE polymer and pigment,
d. collecting the resulting pigmented TFE polymer that was coagulated in step (c).

### Claim 2 (depends on 1)

The process of claim 1 wherein, in step 1, the pigment and the carbonate or bicarbonate or both are mixed in proportion of 50-85% by weight carbonate or bicarbonate and complementally 50-15% by weight pigment.

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

The process of claim 1 or 2, wherein the TFE polymer is TFE homopolymer.

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

The process of claim 1 or 2 wherein in step (b), the amount of the mixture added is between 1 and 5 percent by weight based on TFE polymer.