Process for the production of impact-modified filled polycarbonate compositions

1. A process for producing an impact-modified polycarbonate composition filled with carbon nanotubes, wherein said process produces reduced degradation in molecular weight of said polycarbonate, said process comprising:

(i) in a first step, mixing a Component C comprising carbon nanotubes with Component B comprising a rubber-containing vinyl copolymer and/or Component D comprising a rubber-free vinyl copolymer on a twin screw extruder, to obtain a masterbatch,

wherein:

the rubber-containing vinyl copolymer of Component B comprises at least one graft polymer of

B.1. 5 to 95 wt. % of at least one vinyl monomer on

B.2. 95 to 5 wt. % of at least one graft base with glass transition temperatures of <10° C.,

wherein the B.1 monomer consists of a mixture of

B.1.1 50 to 99 parts by weight vinyl aromatics and/or vinyl aromatics substituted in the nucleus and/or (meth)acrylic acid (C 1 -C 8 ) alkyl esters, and

B.1.2 1 to 50 parts by weight vinyl cyanides and/or (meth)acrylic acid (C 1 -C 8 ) alkyl esters, anhydrides and imides of unsaturated carboxylic acids; and

Component D is selected from the group consisting of thermoplastic vinyl (co)polymers D.1 and terephthalates D.2,

wherein D.1 vinyl (co)polymers comprise

D.1.1 50 to 99 parts by weight vinyl aromatics and/or vinyl aromatics substituted in the nucleus and/or (meth)acrylic acid (C 1 -C 8 ) alkyl esters, and

D.1.2 1 to 50 parts by weight vinyl cyanides and/or (meth)acrylic acid (C 1 -C 8 ) alkyl esters, and/or unsaturated carboxylic acids and/or anhydrides and imides of unsaturated carboxylic acids; and

(ii) in a second step, mixing the masterbatch produced from step (i) with Component A comprising an aromatic polycarbonate and/or aromatic polyester carbonate and optionally with Component B and/or Component D and optionally with an additive on a twin screw extruder.

2. A process according to claim 1 , wherein the first step is carried out at a temperature of from 240 to 300° C.

3. A process according to claim 1 , wherein, in the first step, the ratio of the parts by weight of Component C to the sum of the parts by weight of Components B and D is 2:98 to 25:75.

4. A process according to claim 1 , wherein, in the first step, Components C, B and/or D are introduced into the twin screw extruder simultaneously.

5. A process according to claim 1 , wherein the second step is carried out at a temperature of from 240 to 300° C.

6. A process according to claim 1 , wherein, in the second step, the masterbatch, component A and optionally Component B, and/or Component D and optionally said additive are fed simultaneously or sequentially.

7. A process according to claim 1 , wherein after the first step, the masterbatch is granulated.

8. A process of claim 1 , wherein said additive comprises a flame retardant, anti-drip agent, lubricant, mold release agent, nucleating agent, antistatic, stabilizer, filler, reinforcing agent, dye, and/or pigment.

9. A process according to claim 1 , wherein B.1 the at least one vinyl monomer is present in an amount of 30 to 90 wt %.

10. A process according to claim 1 , wherein B.2 the at least one graft base is present in an amount of 70 to 10 wt %.

11. A process according to claim 1 , wherein D.1.2 comprises maleic acid.

12. A process according to claim 1 , wherein the produced polycarbonate has an average molecular weight that is from 95% to 100% of the average molecular weight of the aromatic polycarbonate and/or aromatic polyester carbonate in component A.

13. A process according to claim 12 , wherein the produced polycarbonate has an average molecular weight that is from 95% to 98% of the average molecular weight of the aromatic polycarbonate and/or aromatic polyester carbonate in component A.

14. A process according to claim 1 , wherein the produced polycarbonate composition comprises

A) 30 to 94 parts by weight of Component A,

B) 5 to 30 parts by weight of Component B,

C) 1 to 10 parts by weight of Component C, and

D) 0 to 30 parts by weight of Component D.

15. A process according to claim 14 , wherein the produced polycarbonate composition comprises

A) 49 to 73 parts by weight of Component A,

B) 10 to 20 parts by weight of Component B,

C) 2 to 6 parts by weight of Component C, and

D) 15 to 25 parts by weight of Component D.

16. A process according to claim 1 , wherein the carbon nanotubes is present in an amount ranging from 2.0% (weight/weight) to 6.0% (weight/weight).

17. A process according to claim 1 , wherein the carbon nanotubes have an external diameter ranging from about 3 nanometers to about 80 nanometers, have a length ranging from about 0.1 micrometers to about 20 micrometers, have from about 2 to 50 graphite layers, and have a minimum internal diameter ranging from about 2 nanometers to about 6 nanometers.