vol. 19, No. 5, Page 3

SYNERGISTIC ANTIOXIDANT

An antioxidant synergist that combines the benefits of the thio- esters and phosphates is described in this paper. The compound,

marketed by the Pennwalt Corp. under the name Anoxsyn 442, is a bis alkyl sulphide containing only carbon, hydrogen, and sul-

phur, and provides good process, colour and long-term stability, and synergism with UV stabilizers. It can be processed at ele- vated temperatures without creating objectionable odours. Con- ventional thioester synergists cannot be used in odour-sensitive applications or where good colour and process stability are re- quired. They also behave antagonistically toward UV stabilizers, and therefore cannot be used in outdoor applications.

Mod. Plast. lnt., 1989, 9, (Feb.), 44-46

HEAT STABILIZATION Polyamide imide and PEEK are two of the various approved poly-

OF PPS merit additives for polyphenylene sulphide which are particu- larly effective as heat stabilizers; especially in the tempera- ture range from 150-35O'C. They reduce the amount of sulphur- containing corrosive gases evolved by up to 75% and therefore increase the upper service temperature of the material in the presence of corrosion-prone components by 20 to 50K. The effec- tiveness of the additives is seen in their radical-stabilizing aromatic structure.

Kunststoffe, 1989, 79, (Jan.), 52-54

VITAMIN E The use of d-alpha-tocopherol (vitamin E) as an antioxidant for AS ANTIOXIDANT polypropylene has been suggested by Nippon Jushi, Kenkyusho in FOR POLYPROPYLENE Japan, particularly for food-contact end-uses. The company has

compared three levels of addition (0.05, 0.10, and 0.15%) with two levels of butylated hydroxytoluene (BHT) and lrganox 1010. It was found that vitamin E discoloured badly, and was not so effective as lrganox 1010 in preventing loss of strength at very high temperatures. However, its effectiveness in preventing oxidation of the polymer during processing was superior to that of either of the traditional additives. Rate of extractionusing N-heptane was comparable to BHT and lrganox 1010, but signifi- cantly higher quantities of vitamin E were leached out by boil- ing water. The company suggest that a synergistic effect with other stabilizers and/or lubricants may be achievable.

Packaging, Japan, 1988, 9, (461, 49

EMBEDDING ADDITIVES A likely method for embedding additives into plastics, such as INTO PLASTICS fragrances, etc. has been developed in Japan by Japan Liquid

Crystal and Seiko Sangyo Co. It is called Cellresin, and is a masterbatch based on a material called cyclodextrin which has the capability of capturing other materials on a molecular basis, depending upon their molecular structure and weight. The "guest" material can include volatile materials such as perfumes or fra-

Cont./......

ADDITIVES FOR POLYMERS

@ 1989 ElswierScience Publishers Ud., England./89/$0.90 + 2.20 No part of this publication may bee reproduced, stored in a retrieval system. or transmitted by any form or by any means, electronic. mechanical. photocopying, reccording or otherwise, without the prior permission of the publishers (Readers in the USA. -please see special regulations listed on back cover.)