Q-Flex QDI, Quinone Diimine Antidegradant - Evidence ofCompetitive Chemistries During Mixing-Part II - Protecting Polymers During Mixing - Continued Developments in Diene / NR Blend Compounds

摘要

Earlier work indicated Quinone diimine antidegradant reacts faster than conventional antidegradants to stabilize broken chains and minimize the oxidative chain degradation that occurs during mixing of NR compounds, preventing the accumulation of low molecular weight polymer. Preserving the molecular weight distribution allows for faster carbon black dispersion which results in achieving lower viscosities much faster, thus reducing processing costs. In spite of the shorter mix cycles, good black dispersion with improved polymer-to-filler interaction provides vulcanizates with comparable or improved performance characteristics. Recent developments expanded this mixing concept to high level diene blends with NR. Preliminary results supported the concept that in the diene based elastomers, radicals react to increase molecular weight thereby increasing viscosity. Thus, the molecular weight building reactions in the diene phase must be limited. This paper presents data from additional comparative mixing studies with quinone diimine, paraphenylene diamine antidegradant or a peptizer, in compounds containing high levels of diene based polymers and NR under various mixing conditions including time, temperature, and rotor speeds.