Bulk moulding compound system

There are several drawbacks to the use of self-bonding compounds which are worthy of mention. To make a self-bonding compound, one must modify the properties of the bulk rubber compound in order to affect the chemistry of the reactions which are required to take place only at the rubber to metal interface. Processing is adversely affected since the compounds want to bond to the mould and metals alike, and the environmental resistance of the rubber to metal bond is generally poor compared to that which is obtained with the use of a conventional rubber to metal adhesive system. 

Metal powders for highly dense plastics compounds have been developed by Ametek Specialty Metal Products, USA. Stainless steel alloys can be used in lock hardware, appliance parts, and exhaust system components. A 50 50 mixture of irregular stainless steel powder and PTFE gives parts with cross direction elongation of 200-240%, 69065 Shore D hardness, and a bulk density of 600— 1000 g 1. The recommended moulding pressure is 500 kg cm and maximum sintering temperature is 3 7 5°C. 

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