INHIBITING ABILITIES OF HYDROAROMATICS AGAINST DETERIORATION OF HYDROCARBON PRODUCTS .2. APPLICATION TO RUBBERS AND PLASTICS

The inhibiting abilities of hydroaromatics due to hydrogen donation were applied to the deterioration of rubbers and plastics. Heavy hydroaromatics from petroleum (HHAP) were produced by hydrogenating the highly aromatic oil fractions derived from petroleum heavy oil by thermal treatment and distillation to meet the requirements (especially low volatility) for additives to rubbers and plastics. First, the inhibiting ability of HHAP due to its hydrogen donation was examined, and excellent results were obtained. Tests were then conducted on natural rubber (NR) and styrene-butadiene rubber (SBR) after the addition of 2 wt% and 5 wt% of HHAP. It was found that the addition of HHAP was very effective in inhibiting the deterioration of NR, exceeding the effect of the conventional inhibitor IPPD (phenylisopropyl-p-phenylenediamine). Furthermore, low contamination was observed by adding HHAP, in addition to other effects such as lowering Mooney viscosities and improving bending properties. Next, HHAP was applied to plastics. It was found that the addition of HHAP from 0.1-0.5 wt% was effective for inhibition of the deterioration of polyolefins (polyethylene and polypropylene) at 120-degrees-C and 270-degrees-C in air. Moreover, excellent inhibiting ability of HHAP against degradation by radiation (gamma-ray and electron beam) was found for polyolefin plastics. It was confirmed that the inhibiting abilities of hydroaromatics described in Part 1 could be applied to rubbers and plastics.