DuPont: New polyacetal optimises impact performance, flow and cost-efficiency

The launch of DuPont™ Delrin® 300CP (www.dupont.com) marks the development of a new polyacetal (polyoxymethylene, POM) offering a distinct combination of properties. The engineering thermoplastic combines high impact resistance, even at low temperatures, with high stiffness, strength and elongation at yield – yet it is particularly efficient during processing, thanks to its relatively low melt viscosity. The cost of the new resin is around that of standard polymer grades. The broad range of potential applications includes automotive components, sports and leisure products as well as mass-produced articles such as fasteners, clips or spring elements.

Designers have typically had to make compromises when balancing mouldability, mechanical performance and low temperature toughness in acetal parts. New Delrin® 300CP now provides an almost universal solution. The material demonstrates consistent impact performance over a broad temperature range. For example, its notched Charpy impact strength of 10.5 kJ/m2, at room temperature, only falls to 10 kJ/m2 at -30 °C, whereas other, specially impact-modified copolymers experience substantial falls in this value at such temperatures (e.g. from 13 kJ/m² to 8 kJ/m² with a high impact-resistant copolymer). Its high elongation at yield and simultaneously high stiffness and creep resistance help extend its application in the design of continuously-loaded, spring-elastic components.

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Delrin® 300CP presents greater design flexibility and freedom by combining high melt-flow with mechanical performance at levels that were, to date, only possible with polyacetals of considerably higher viscosity. This enables the reduction of wall thicknesses and material usage while maintaining load capacity, the design of more complex components, or – at the same wall thickness – the use of longer flow distances. At the same time, the low viscosity of the melt improves weld line strength, thereby facilitating tool optimisation, e.g. the use of several injection gates. Thanks to its high heat deflection temperature, Delrin® 300CP can be used at considerably higher temperatures than comparable copolymers. Of additional benefit to the processor: the material does not need to be pre-dried.

As is typical for all Delrin® polyacetals, the new grade 300CP provides high surface hardness, very low wear and friction, resiliency and a high resistance to chemicals and solvents. Potential applications include automotive components such as fasteners, seatbelt components, levers, brackets, gears and switches, buckles, latches or surface parts for sporting goods, hardware for windows and doors, parts for domestic and commercial irrigation systems, as well as general components with snap-in joints.

DuPont de Nemours (Deutschland) GmbH, Neu-Isenburg, Germany

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