ANTIOXIDANTS AND STABILISERS | ADDITIVES Delivering a stable future
Stabiliser producers are working at pace to meet new demands such as recyclability and sustainability while matching or exceeding current performance. Peter Mapleston learns more
It seems development activity in antioxidants and stabilisers for thermoplastics has never been as fevered as now. Additive suppliers are working on new products that address multiple issues: the need to make better use of post-consumer recy- clate, the call for reduced contamination in food- contact materials, a general demand for improved sustainability, and improved cost-effectiveness. To those, of course, can be added the basic require- ment of simply obtaining product in today’s very tight market. This article takes a look at a few of the many developments going on around the world. US-headquartered Dover Chemical says it has developed a new technology platform of polymeric process stabilisers. The function of the stabiliser is as a sacrificial additive that will allow as much of the polymer’s original properties to be retained after processing in a twin screw extruder. This is especially important when plastics are recycled, the company says. Colour is an indicator of how well a stabiliser performs. Tests at the company show its new stabiliser — Doverphos LGP12 — performs better than standard stabilisers, which see the polymer becoming progressively darker after each recycling step (Figure 1).
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Dover says the new stabilisers are made from
biodegradable materials and do not contain substances of very high concern (SVHC). Their polymeric nature greatly reduces migration and human exposure in food contact applications. “Besides offering excellent process stability and colour retention, they also have enhanced ancillary effects that are not common to currently used commercial phosphites, such as improved process- ing and reduced melt fracture as well as improved gamma irradiation and NOx gas fade resistance,” says Dr Michael Davies, Director EMEA. The prod- ucts can also be used in post-consumer LLDPE film recyclate to reduce gels as well as improve colour. Many polymer producers, compounders, and
brand owners today are paying increasing attention to the issue of Non-Intentionally Added Substances (NIAS) in food packaging, according to Sumitomo Chemical. The company says its Sumilizer GP stabiliser, part of its Sumilizer G series, is particularly useful in this regard. It is a high performance hybrid-type antioxidant containing phenolic and phosphite moieties within a single molecule. It is already well established in Japan for use in various polymers — mostly polyolefins but also PS — and Sumitomo is now expanding its marketing globally.
Main image: stabiliser chemistries that enable repeated recycling with minimal loss of performance are just one of many demands being placed on developers
� September 2021 | COMPOUNDING WORLD 81
IMAGE: SHUTTERSTOCK
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