Overview

Designers of electrical and electronic components have a wide choice of polymers at their disposal and this report lists the most commonly used with brief notes on their properties. One of industry's main concerns is the implementation of the European Restriction of Hazardous Substances (RoHS) 2002/95/EC directive. The regulations relate to eight distinct categories of equipment including, for example, consumer electronics which comprises such items as television sets, audio equipment, video recorders and digital cameras. Products must not contain any of the following substances in excess of the prescribed levels of 0.01% for cadmium and 0.10% for lead, mercury, hexavalent chromium, polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE). The implementation of the legislation heralds the arrival of a new generation of lead-free solders and solder paste whose melting points are around 34 C higher than their predecessors. This change dramatically affects the selection of polymers for specific applications. Polymer suppliers have risen to the challenge by changing product formulations to comply with the new requirements.

Cost and competition are imposing ever more stringent specification criteria on the equipment designer who, in turn, is demanding significantly improved performance from his polymer supplier. The role of mineral fillers in plastic compounds is changing. In the past they were used to reduce costs by replacing polymer content by a less expensive material. Now they have a more important role to play since their use can modify processing characteristics or the properties of the finished part. Other uses include their ability to...