Implantable medical catheter having reinforced silicone elastomer composition

An implantable medical catheter, the catheter defining at least one fluid passageway and comprising a cured elastomer composition obtained by crosslinking an uncured blend composition that comprises an intimately admixed mixture that comprises the following components:

• (A) silica that had been silyliated by treatment and contains trialkylsilyl groups comprising approximately 23 to 45 percent by weight of the mixture;
• (B) a polysiloxane copolymer composed of divalent —R1R2SiO—, divalent —R3R4SiO— and end-blocking R5R6R7SiO— units, comprising approximately 55 to 77 percent by weight of the mixture,
• where R1 and R2 independently are lower alkyl of 1 to 6 carbons, phenyl or trifluoropropyl, R3 is vinyl, allyl, or other olefinic group having up to 4 carbons, R4 is lower alkyl of 1 to 6 carbons, phenyl or trifluoropropyl, and R5, R6, and R7 independently are lower alkyl of 1 to 6 carbons, phenyl, vinyl, allyl, or other olefinic group having up to 4 carbons and one double bond, the polysiloxane copolymer has a degree of polymerization (D.P.) approximately in the range of 3500 to 6500, and the olefin containing —R3R4SiO— groups are present randomly distributed in the polysiloxane copolymer and approximately in the 0.05 to 0.3 mol percent range, with the provisos that when R1, or R2, or both represent phenyl groups then proportion of the phenyl-containing divalent siloxane units does not exceed 15 mol percent and when R1 or R2 or both represent trifluoropropyl groups, then the proportion of the trifluoropropyl-containing divalent siloxane units does not exceed approximately 40 mol percent in the polysiloxane copolymer;
• (C) a catalyst, and
• (D) an organohydrogen polysiloxane cross-linker, the catalyst and the cross-linker being present in the uncured blend composition in sufficient amount to cause the cross-linking reaction to occur.