# US 4,397,975 A · Heat stabilized polymers

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- Number: US 4,397,975 A
- Document ID: US4397975A
- Status: Granted
- Kind: A
- Application number: 06/324,900
- Filed: 1981-11-25
- Granted: 1983-08-09
- Earliest claimed: 1981-11-25
- Assignees: Monsanto Company
- Inventors: Alva F. Harris
- Web page: https://patentgrep.com/patent/US4397975A

## CPC

- C08K 3/30: Sulfur-, selenium- or tellurium-containing compounds
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## Abstract

The tendency to crosslink of polymer compositions comprising polymer units derived from acrylonitrile and maleic anhydride is controlled by the use of a sulfur acid.

## Claims

### Claim 1

A polymeric composition having a reduced tendency to crosslink during fabrication, which composition comprises a polyblend of (a) a styrene maleic/anhydride polymer containing 50 to 83% by weight of styrene, from 10 to 35% by weight of maleic anhydride and from 0 to 20% by weight of methyl methacrylate; (b) a polymer selected from the group consisting of acrylonitrile-butadiene-styrene polymers having an acrylonitrile content of at least 8% by weight and styrene-acrylonitrile polymers having an acrylonitrile content from 20 to 70% by weight; and (c) an effective amount from about 0.001 to 0.005 mole per 100 gm of polymer, of a sulfur acid.

### Claim 2 (depends on 1)

A polymeric composition according to claim 1 in which the sulfur acid is an organic sulfonic acid.

### Claim 3 (depends on 1)

A polymeric composition according to claim 1 in which the sulfur acid is an aromatic sulfonic acid.

### Claim 4 (depends on 1)

A polymeric composition according to claim 1 in which the sulfur acid is para-toluene sulfonic acid and is present in an amount of from 0.002 to 0.004 mole per 100 gm of polymer.