ELASTOSIL® R plus 4305/70 US
ELASTOSIL® R plus 4305/70 US HCR silicone rubbers are addition-curing, two part compounds (batch grades). The vulcanizates show excellent transparancy and good to very good mechanical properties. Properly postcured vulcanizates of ELASTOSIL® R plus 4305/70 US comply with BfR and FDA food contact regulations. The material also passes USP XXIII Class VI.
ELASTOSIL® R plus 4305/70 US may not be cured with peroxides, only with the catalyst batch ELASTOSIL® AUX PT1.
ELASTOSIL® R plus 4305/70 US and Curing Agent PT 1 are mixed homogeneously on a roll mill in a ratio of 100 : 1.5. Care must be taken to keep the mill and compound as cool as possible during mixing.
The temperature of the rubber should not exceed 35°C or risk partial curing and reduced pot life.
Crosslinking begins when Curing Agent PT 1 has been added. The rate and degree of crosslinking depends on the storage time and temperature.
At 23°C, the mixture has a pot life of about 24 hours. This can be extended by storing the catalyzed mixture at a lower temperature.