Impact-modified polycarbonate compositions having a good combination of natural color, hydrolytic stability and melt stability
View Patent ↗The present invention relates to polycarbonate compositions comprising A) from 10 to 99 parts by weight, in each case based on the sum of components A+B+C, of aromatic polycarbonate and/or aromatic polyester carbonate, B) from 1 to 35 parts by weight, in each case based on the sum of components A+B+C, of rubber-modified graft polymer of B.1 from 5 to 95 wt. % of at least one vinyl monomer on B.2 from 95 to 5 wt. % of one or more graft bases having a glass transition temperature <10° C., C) from 0 to 40 parts by weight, in each case based on the sum of components A+B+C, of vinyl (co)polymer and/or polyalkylene terephthalate, D) from 0 to 50 parts by weight, in each case based on the sum of components A+B+C, of phosphorus-containing flameproofing agent, E) from 0 to 1.0 part by weight, in each case based on the sum of components A+B+C, of acidic additives, and F) from 0 to 50 parts by weight, in each case based on the sum of components A+B+C, of additives, wherein component B is obtainable by reacting component B.1 with the graft base B.2 by means of emulsion polymerization, with the proviso that in those compositions that are free of components D) and E), the graft polymer dispersion in the spray drying or in the precipitation has a pH value of less than 7, characterized in that there are used in the graft reaction from 0.1 to 5 parts by weight (based on the sum of the parts by weight of the monomers B.1 and of the graft base B.2 that are used=100 parts by weight) of at least one emulsifier selected from the group consisting of alkali, alkaline earth, ammonium and phosphonium salts of a saturated fatty acid having from 10 to 50 carbon atoms, wherein the emulsifier or emulsifiers remains or remain in component B, and also to a process for the preparation of these polycarbonate compositions and to the use of the polycarbonate compositions in the production of molded bodies, and to the molded bodies themselves.
1. A composition comprising
A) from 10 to 99 parts by weight, in each case based on the entirety of components A+B+C, of aromatic polycarbonate and/or aromatic polyester carbonate,
B) from 1 to 35 parts by weight, in each case based on the entirety of components A+B+C, of rubber-modified graft polymer of
B.1 from 5 to 95 wt. % of at least one vinyl monomer on
B.2 from 95 to 5 wt. % of one or more graft bases having a glass transition temperature <10° C.,
wherein the rubber-modified graft polymer component B) comprises 0.1 to 5 parts by weight of an emulsifier comprising potassium stearate (C 17 H 35 COOK), or sodium stearate (C 17 H 35 COONa), or a combination thereof, based on the total weight of the at least one vinyl monomer B.1 and the graft base B.2,
C) from 0 to 40 parts by weight, in each case based on the entirety of components A+B+C, of resinous, thermoplastic and rubber-free vinyl (co)polymer and/or polyalkylene terephthalate,
D) from 0 to 50 parts by weight, in each case based on the entirety of components A+B+C, of phosphorus-containing flame retardant,
E) from 0 to 1.0 part by weight, in each case based on the entirety of components A+B+C, of acidic additives and
F) from 0 to 50 parts by weight, in each case based on the entirety of components A+B+C, of additional substances,
wherein component B is obtained by reacting component B.1 with the graft base B.2 by emulsion polymerisation, with the proviso that, in the case of compositions that are free of components D) and E), the pH of the graft polymer dispersion during a precipitation step is less than 7, and
the graft polymer is precipitated from the dispersion by addition of magnesium sulphate, where the emulsifier or emulsifiers and magnesium sulphate remain in component B.
2. A composition according to claim 1 , wherein the graft reaction uses from 0.3 to 2.5 parts by weight (based on the entirety of the parts by weight of the monomers B.1 used and of the graft base B.2=100 parts by weight) of the emulsifier.
3. A composition according to claim 1 , wherein the graft reaction uses from 1.5 to 2.5 parts by weight (based on the entirety of the parts by weight of the monomers B.1 used and of the graft base B.2=100 parts by weight) of the emulsifier.
4. A process for the preparation of an impact-modified polycarbonate moulding compositions, where the composition comprises
A) from 10 to 99 parts by weight of aromatic polycarbonate and/or aromatic polyester carbonate,
B) from 1 to 35 parts by weight of rubber-modified graft polymer of
B.1 from 5 to 95 wt. % of at least one vinyl monomer on
B.2 from 95 to 5 wt. % of one or more graft bases having a glass transition temperature <10° C.,
wherein the rubber-modified graft polymer component B) comprises 0.1 to 5 parts by weight of an emulsifier comprising potassium stearate (C 17 H 35 COOK), or sodium stearate (C 17 H 35 COONa), or a combination thereof, based on the total weight of the at least one vinyl monomer B.1 and the graft base B.2,
C) from 0 to 40 parts by weight of resinous, thermoplastic and rubber-free vinyl (co)polymer and/or polyalkylene terephthalate,
D) from 0 to 50 parts by weight, in each case based on the entirety of components A+B+C, of phosphorus-containing flame retardant,
E) from 0 to 1.0 part by weight, in each case based on the entirety of components A+B+C, of acidic additives, and
F) from 0 to 50 parts by weight, in each case based on the entirety of components A+B+C, of additional substances,
wherein the process comprises mixing components A)-F) either in succession or simultaneously, at a temperature of 20° C. or higher and, compounding components A)-F) in the melt and extruding components A)-F) in the melt, at temperatures of from 260° C. to 300° C.,
wherein the impact modifier comprises rubber-modified graft polymer (component B) which is prepared by reacting component B.1 with the graft base B.2 by emulsion polymerisation, where
(i) in a first step, the rubber base B.2 is prepared directly in the form of an aqueous dispersion by free-radical emulsion polymerisation or is dispersed in the water,
(ii) in a second step, the reaction of component B.1 with the graft base B.2 (referred to hereinbelow as “graft reaction”) is carried out by emulsion polymerisation, where
1) component B.2 dispersed in water,
2) from 0.1 to 5 parts by weight (based on the entirety of the parts by weight of the monomers B.1 used in the preparation of the graft polymer B and of the graft base B.2=100 parts by weight) of the emulsifier is used, and the monomers according to component B.1 and free-radical generators and optionally molecular weight regulators are added to the rubber base dispersion obtained in step (1),
3) work-up is carried out by
3.1) precipitation with magnesium sulphate and
3.2) separation of the dispersing water,
with the proviso that, in the case of compositions that are free of components D) and E), the pH of the graft polymer dispersion during the precipitation step (3.1) is less than 7,
wherein the resulting moist graft polymer is not washed with additional water, and wherein the emulsifier or emulsifiers and magnesium sulphate remain in component B.
5. A process according to claim 4 , wherein the graft reaction uses from 0.2 to 2.5 parts by weight (based on the entirety of the parts by weight of the monomers B.1 used and of the graft base B.2=100 parts by weight) of the emulsifier.
6. A process according to claim 4 , wherein the graft reaction uses from 1.5 to 2.5 parts by weight (based on the entirety of the parts by weight of the monomers B.1 used and of the graft base B.2=100 parts by weight) of the emulsifier.
7. A moulding or semi-finished product obtained by the process according to claim 4 .
8. A moulding or semi-finished produced prepared from a composition according to claim 1 .
9. A composition according to claim 1 , comprising 0.01 to 1.0 part by weight, in each case based on the entirety of components A+B+C, of acidic additives (E).
10. A composition according to claim 1 , comprising 0.02 to 0.5 part by weight, in each case based on the entirety of components A+B+C, of acidic additives (E).
11. A process according to claim 4 , wherein the composition comprises 0.01 to 1.0 part by weight, in each case based on the entirety of components A+B+C, of acidic additives (E).
12. A process according to claim 4 , wherein the composition comprises 0.02 to 0.5 part by weight, in each case based on the entirety of components A+B+C, of acidic additives (E).
13. A composition according to claim 1 , wherein the emulsifier used in the graft reaction is potassium stearate.
14. A process according to claim 4 , wherein the emulsifier used in the graft reaction is potassium stearate.
15. A composition according to claim 1 , wherein the emulsifier used in the graft reaction is sodium stearate.
16. A process according to claim 4 , wherein the emulsifier used in the graft reaction is sodium stearate.
17. A composition according to claim 1 , comprising 1 to 30 part by weight, in each case based on the entirety of components A+B+C, of component C).
18. A composition according to claim 1 , comprising 1 to 40 parts by weight, in each case based on the entirety of components A+B+C, of component D).
19. A composition according to claim 1 , comprising 0.5 to 25 parts by weight, in each case based on the entirety of components A+B+C, of component F).