Bonding of Liquid Rubber LR

The curing characteristics of LR will be described first as they differ from those for HTV. 

The curable composition of LR (component A mixed with component B) consists of two sorts of polydimethylsiloxane (PDMS) molecules. One contains vinyl groups on the ends 

This mixture is called addition curing, because silicon-vinyl groups and silicon-hydrogen groups add to each other in the presence of platinum and heat. An advantage of this curing mechanism is the absence of peroxides and their by-products and, moreover, the fast speed of curing. 

HTV rubber is available as peroxide or addition curing. In some applications LR is not capable of out performing HTV rubber. LR is perfect for a vast number of applications, but if very high mechanical properties are required, HTV will be the rubber of choice. 

The recently developed self-adhesive HTV silicone rubbers are addition curing, one component materials which remain processable for several weeks at room temperature. Self-adhesive liquid silicone rubbers are always delivered as two components. This is due to the fact that once components A and B are mixed the processing time is approximately 3-10 days at room temperature. 

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