Core-shell structured silicone rubber graft polymers, impact-resistant modified molding compounds and molded bodies and method for producing the same

2:

• The silicone rubber graft copolymer as claimed in claim 1, wherein the initiator is added in at least three portions to the reaction vessel, each addition taking place after at least 2 minutes.

3-4. (canceled)

5:

• The silicone rubber graft copolymer as claimed in claim 1, wherein the monomers and the initiator are added in the form of a mixture to the reaction vessel.

6:

• The silicone rubber graft copolymer as claimed in claim 1, wherein the concentration of initiator in the reaction vessel is kept below 0.05% by weight, based on the entire reaction mixture.

7:

• The silicone rubber graft copolymer as claimed in claim 1, wherein between the core a) and the shell c) there is another spherical polydialkylsiloxane layer b) present, comprising (R2SiO2/2) units.

8:

• The silicone rubber graft copolymer as claimed in claim 1, wherein the particle diameter of the silicone rubber graft copolymer is in the range from 10 to 300 nm.

10:

• The silicone rubber graft copolymer as claimed in claim 1, wherein the shell c) comprises at least one polymerized (meth)acrylate.

11:

• The silicone rubber graft copolymer as claimed in claim 10, wherein the shell c) is prepared via polymerization of a mixture in which methacrylates and acrylates are present.

12:

• The silicone rubber graft copolymer as claimed in claim 11, wherein the shell c) is prepared via polymerization of a mixture in which methyl methacrylate and at least one acrylate having from 1 to 8 carbon atoms are present.

13:

• The silicone rubber graft copolymer as claimed in claim 1, wherein vinyl groups are present in the core a) prior to preparation of the organic shell c).

14:

• The silicone rubber graft copolymer as claimed in claim 13, wherein the content of the vinyl groups in the core a) is in the range from 2 to 3 mol %, based on the weight of the core.

15:

• A process for preparing a silicone rubber graft copolymer as claimed in claim 1, wherein a core is prepared from polysiloxane by the emulsion polymerization process, and then organic monomers are grafted onto the resultant polysiloxane by a free-radical route, the initiator being added continuously during the free-radical polymerization.

16:

• The process as claimed in claim 15, wherein butyl hydroperoxide is used as initiator.

17:

• A molding composition comprising at least one silicone rubber graft copolymer as claimed in claim 1.

18:

• The molding composition as claimed in claim 17, wherein the molding composition comprises at least one poly(meth)acrylate.

19:

• The molding composition as claimed in claim 17, wherein the molding composition comprises at least one styrene-acrylonitrile polymer.

21:

• The molding composition as claimed in claim 17, wherein the molding composition further comprises at least one acrylate-rubber-based impact modifier.

23:

• An impact-resistant molding produced from the molding composition as claimed in claim 17.

24:

• The impact-resistant molding as claimed in claim 23, wherein the molding has a Vicat softening point according to ISO 306 (B50) of at least 85° C., a notched impact strength NIS (Izod 180/1eA, 1.8 MPa) according to ISO 180 of at least 3.0 kJ/m2 at −20° C. and of at least 2.5 kJ/m2 at −40° C., a modulus of elasticity according to ISO 527-2 of at least 1500 MPa.

25:

• The silicone rubber graph copolymer as claimed in claim 1, wherein the initiator is added in at least three portions, at least 10 minutes apart.

26:

• The silicone rubber graph copolymer as claimed in claim 1, wherein the initiator is added in at least three portions, at least 20 minutes apart.

27:

• The silicone rubber graph copolymer as claimed in claim 1, wherein the weight ratio of the amount of the initiator added during the polymerization to the amount of the initiator present at the start of polymerization is at least 20.