Reactive processing reaction injection moulding

Note 3 Reaction injection moulding and reinforced reaction injection moulding are types of reactive polymer processing. 

Reaction injection moulding (RIM) is a low-pressure process that allows two reactive streams, A and B say, to meet and react to form a cured polymer in the mould. Figure 6.16 shows the process in a simplified form. 

RRIM polyurethanes are an extension to Reaction Injection Moulding (RIM) which is a relatively recent, but now established, plastics processing technique. Simplified, RRIM is the inclusion of a reinforcement - short glass fibres - into one of the components used in the RIM process. However, the inclusion of glass reinforcement into one of the reactive components, usually the polyol, has meant that certain processing equipment modifications were necessary in order to handle the... 

The production of integral foams requires the metering and fast mixing of reactive components and the injection of the resulting mixture into a closed mould. This process is known as reaction injection moulding (RIM). It may be noted that reaction injection moulding is applied mainly to polyurethanes but the process can be used with other systems, e.g. polyamides (see section 10.2.3(d)). 

The move to couple reaction and processing will continue. Reactive injection moulding is a good way to get round the high viscosity processing problem in that the low viscosity material is fed into the mould and the reaction completed within the material. This of course can lead to other complicating issues. 

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