NOVEL ALKYL THIOPROPIONATE STABILIZERS FOR POLYOLEFINS.

The susceptibility of polyolefins to oxidation requires the incorporation of an antioxidant or antioxidant system to protect the polymer during elevated-temperature processing and during its useful service life. In addition to primary antioxidants based on hindered or partially hindered phenols, secondary, sulfur-containing antioxidants are often included to provide long-term stability. The synergistic action of these sulfur-containing antioxidants with the higher-priced phenolics often allows a substantial reduction in use levels of the phenolics. This paper presents data which demonstrated that pentaerythritol tetraesters of alkylthiopropionic acid, so far used as secondary antioxidants or synergists, showed good heat stability, low volatility and high compatibility.