Discoloration Resistant Polyolefin Films - Part 2: Phenol vs. Phenol Free Stabilization and the Impact of Selected Grades of TiO2, 2002 PLACE Conference Proceedings

The preservation of physical properties and aesthetics are two key measures for film products. As such, one needs to be selective in terms of choosing the polymer and stabilization systems that are used to derive robust and attractive film products. In selected applications, it is particularly desirable to have film products that do not discolor during processing; and more importantly, while the product is kept in storage. Under a selected set of circumstances, certain types of phenolics have been shown to be susceptible to discoloration, due to various factors; some of which can be controlled, others not. For example, inadequate stabilizer concentrations, harsh processing conditions, improper selection of white pigments (TiO2), and/or prolonged storage of the films in a environment containing oxides of nitrogen (pollution). Approaches to eliminate discoloration, by using “phenol” and “phenol free” stabilization systems without and with two types of TiO2 will be discussed. Overall, “phenol free” stabilization systems are highly recommended for color critical polyolefin film applications.