HNBR compounds having an improved flowability

1 . A composition comprising at least one hydrogenated nitrile rubber and at least one organopolysiloxane with at least one hydrocarbon radical having less than four carbon atoms.

2 . A composition according to claim 1 , wherein the organopolysiloxane has at least one hydrocarbon radical having less than four carbon atoms and has the general structure (I)

R″ 2 R′SiO—(R″R′SiO) m —(R″ 2 SiO) n —SiRR″ 2   (I)

wherein R and R′ and R″ may be the same or different and are independently a substituted or unsubstituted monovalent hydrocarbon radical with in the range of from 1 to 3 carbon atoms, and m/n is equal or less than 1.

3 . A composition according to claim 2 , wherein the organopolysiloxane is polydimethylsiloxane (PDMS).

4 . A composition according to claim 1 , wherein the hydrogenated nitrile rubber comprises repeating units derived from at least one conjugated diene, at least one alpha, beta-unsaturated nitrile and optionally further one or more copolymerizable monomers.

5 . A composition according to claim 1 , further comprising one or more fillers and/or one or more vulcanization agents or curing systems.

6 . A composition according to claim 1 , wherein the composition has improved flowability.

7 . A composition according to claim 1 , wherein the composition has an improved fluid aging resistance.

8 . A method of improving the flowability of a composition comprising adding at least one organopolysiloxane with at least one hydrocarbon radical having less than four carbon atoms to least one hydrogenated nitrile rubber.

9 . A method of improving the fluid aging of a composition comprising adding at least one organopolysiloxane with at least one hydrocarbon radical having less than four carbon atoms to at least one hydrogenated nitrile rubber.

10 . A process for the manufacture of a shaped article comprising injection molding, extrusion molding or compression molding a composition according to claim 1.