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Product details
Silicone rubbers have excellent low temperature flexibility combined with outstanding high temperature resistance. Their service temperatures range from −70 °C to 250 °C.46 Silicone rubbers commonly used in pressure-sensitive adhesives are the dimethylsiloxanes or their phenyl-modified versions, shown in (5), where R = Me or (up to 25 mol %) Ph. The modification with phenyl groups gives materials with higher tack, low temperature flexibility (by preventing crystallization at −40 °C) and increased high temperature stability. These linear gums are blended with highly branched silicon resins—prepared by condensation of trimethyl(chloro)silane with silicic acid—to adjust tack as well as the physical properties of the adhesive.