Phenol and Phenol Free -- Stabilization of High Density Polyethylene, 1998 Polymers, Laminations & Coatings Conference Proceedings

Traditional stabilizer systems for polyolefns are typically based on a combination of a phenolic antioxidant, a phosphorus based melt processing stabilizer, (plus an acid acceptor for Ziegler-Natta type polymers). The phenolic antioxidant provides melt processing stability as a hydrogen atom donor and free radical scavenger, but is also incorporated for some desired level of short term {storage) or long term thermal stability. The phosphorus based melt processing stabilizer, functions as a hydroperoxide decomposer during the melt compounding step. These chemistries work together to help maintain the original molecular architecture of the polymer as it moves through its life cycle, both above and below the melting point of the polymer.

Recently, powerful new stabilizers based on hydroxylamine and lactone chemistry have been introduced. Investigations have been underway to examine the impact of both “phenol” and ‘phenol free” based formulations in regard to enhancing the pegormance of traditional stabilization systems. These new developments lead to improved physical and aesthetic properties. In this paper we will review peeormance data regarding the stabilization of high molecular weight density polyethylene. Both stabilization concepts have been explored and each have strengths for specific end-use applications. The relative pelformance of these “‘phenol” and “‘phenol free” stabilizer systems and their applicability to existing and new markets will be discussed.