Addition-crosslinkable silicone compositions with low coefficients of friction
Addition-crosslinkable silicone compositions contain (A) 100 parts by weight of polydiorganosiloxane(s) which has alkenyl groups and whose viscosity is from 5000 to 50,000,000 mPas at 25° C., having at least 2 alkenyl groups per molecule, and at least 0.15 mol % of alkenylsiloxane units, based on all siloxane units, (B) from 1 to 50 parts by weight of polydiorganosiloxane(s) whose viscosity is at least 5,000,000 mPas at 25° C., and having no alkenyl groups, (C) SiH-functional crosslinking agent(s), (D) hydrosilylation catalyst(s), and (E) from 3 to 90 parts by weight of filler(s) whose BET specific surface area is at least 50 m 2 /g. Vulcanizates of the addition-crosslinkable silicone compositions have low coefficients of friction.
1. An addition-crosslinkable silicone composition, comprising
(A) 100 parts by weight of polydiorganosiloxane(s) having at least 2 alkenyl groups per molecule, whose viscosity is from 2,000,000 to 50,000,000 mPas at 25° C., and having at least 0.15 mol% of alkenylsiloxane units, based on all of the siloxane units,
(B) from 1 to 50 parts by weight of polydiorganosiloxane(s) having no alkenyl groups and whose viscosity is at least 5,000,000 mPas at 25° C.,
(C) at least one SiH-functional crosslinking agent,
(D) at least one hydrosilylation catalyst, and
(E) from 3 to 90 parts by weight of at least one filler whose BET specific surface area is at least 50 m 2 /g.
2. The composition of claim 1 , wherein at least one polydiorganosiloxane (A) has a viscosity of from 9,000,000 to 40,000,000 mPas.
3. The composition of claim 1 , wherein polydiorganosiloxane(s) (B) have a viscosity of 7,000,000 to 40,000,000 mPas.
4. The composition of claim 2 , wherein polydiorganosiloxane(s) (B) have a viscosity of 7,000,000 to 40,000,000 mPas.
5. The composition of claim 1 , wherein polydiorganosiloxane(s) (B) have a viscosity of 9,000,000 to 35,000,000 mPas.
6. The composition of claim 3 , wherein polydiorganosiloxane(s) (B) have a viscosity of 9,000,000 to 35,000,000 mPas.