# US 4,391,930 A · Stabilized suspension of glass bubbles in an aqueous dispersion of tetrafluoroethylene polymer

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- Number: US 4,391,930 A
- Document ID: US4391930A
- Status: Granted
- Kind: A
- Application number: 06/347,927
- Filed: 1982-02-11
- Granted: 1983-07-05
- Earliest claimed: 1980-11-07
- Assignees: E. I. DuPont de Nemours and Company
- Inventors: Allan H. Olson
- Web page: https://patentgrep.com/patent/US4391930A

## CPC

- C08J 9/32: from compositions containing microballoons, e.g. syntactic foams
- C08J 3/03: in aqueous media
- 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

Hollow glass bubble-containing aqueous dispersions of tetrafluoroethylene polymer having good shelf life are provided, said dispersions also containing nonionic surfactant and water soluble electrolyte.

## Claims

### Claim 1

A stabilized suspension of glass bubbles in an aqueous dispersion of tetrafluoroethylene polymer, which suspension comprises
(a) water having dispersed therein 45-75% by weight, based on water, of a tetrafluoroethylene polymer having a melt viscosity of at least 1.times.10.sup.9 poises at 380.degree. C.,
(b) 5 to 10% by weight, based on polymer, of a nonionic surfactant,
(c) 0.1 to 0.5% by weight, based on water and polymer, of a water-soluble electrolyte, and
(d) 2 to 8% by weight, based on polymer, of glass bubbles having a density between 0.20 and 0.40 g/ml and an average size between 20 and 130 micron,
said dispersion having a viscosity between 135 and 300 cps at 25.degree. C.

### Claim 2 (depends on 1)

The dispersion of claim 1 wherein the polymer concentration is 55 to 65% by wt.

### Claim 3 (depends on 1)

The dispersion of claim 1 wherein the polymer is polytetrafluoroethylene.

### Claim 4 (depends on 1)

The dispersion of claim 1 wherein the surfactant concentration is from 5.0 to 8.0% by weight.

### Claim 5 (depends on 1)

The dispersion of claim 1 wherein said electrolyte is an inorganic barium salt.

### Claim 6 (depends on 1)

The dispersion of claim 1 wherein said electrolyte is an ammonium citrate.

### Claim 7 (depends on 1)

The dispersion of claim 1 wherein the nonionic surfactant is an ethoxylated aliphatic alcohol or ethoxylated alkyl phenol.

### Claim 8 (depends on 1, 2, 3, 4, 5, 6, 7)

The dispersion of claim 1, 2, 3, 4, 5, 6 or 7 wherein the glass bubbles have a density of between about 0.36 and 0.39 g/ml.