New crosslinkable PBT compounds from Dimelika
By Barry Copping
Posted 6 September 2012
Dimelika Plast, headquartered in Brühl in Germany’s Baden region, is expanding its CompaDur polyester family to include radiation-crosslinkable PBT compounds.
According to the company, radiation treatment of engineering plastics makes it possible to use cheaper materials in applications requiring resistance to high temperatures.
Finished plastic components are irradiated with a precisely calibrated dose of beta and gamma rays. Radiant energy is absorbed by the material, chemical bonds are split and free radicals are formed. These rearrange and recombine to achieve the desired thermal and mechanical properties.
Dimelika cites a higher heat distortion temperature, greater glow-wire resistance and better flame retardancy, along with improved resistance to abrasion, ageing, chemicals and stress cracking. Improved fibre/matrix adhesion is said to enhance component stiffness.
According to the company, radiation crosslinking renders engineering plastics suitable for environments around lead-free soldering (up to 280°C) and short-term high-temperature soldering (up to approx. +450°C) – conditions which it says were previously the domain of thermosets.
The crosslinkable CompaDur PBT compounds contain an additive package which is not sensitive to temperature. No mould changes or modifications to moulds are required, and the additive package does not affect the compound’s cooling and shrinkage behaviour. Because radiation crosslinking takes place after injection moulding, components remain dimensionally and inherently stable throughout the crosslinking process, says Dimelka. The is usable alongside filler materials, reinforcing agents and functional additives, enabling components with improved stiffness and noise damping properties to be produced.
Liborius Flöper, Dimelika’s managing director, said projects are “already at advanced stages” in automotive electrics – underbonnet components subjected to high thermal loads – and in the electrical and electronics industries.
To serve markets in Europe more efficiently, the company has upgraded its sales structure. CompaDur materials are available in the UK via Rugeley-based K.D. Feddersen.
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