Polycarbonate composition with improved melt-flowability

1. A process for producing a composition comprising a melt polycarbonate, at least one phosphine of formula (I), and at least one aliphatic carboxylic ester:

wherein

Ar 1 and Ar 2

are, identically or differently optionally substituted aryl moieties, and

R′ is an optionally substituted aryl moiety or one of the following moieties (Ia) to (Ih)

wherein

R is an optionally substituted C 6 -C 14 -aryl moiety,

n and m

are respectively and independently of one another an integer from 1 to 7 and wherein the H atoms of moieties (Ia) to (Ic) are optionally replaced by substituents, and with the proviso that R′ can also be optionally substituted 4-phenyl-phenyl or optionally substituted α-naphthyl if both of the Ar moieties in formula (I) are also respectively optionally substituted 4-phenyl-phenyl or optionally substituted a α-naphthyl;

said process comprising introducing said at least one phosphine of formula (I) and said at least one carboxylic ester into the melt stream of said melt polycarbonate via an ancillary extruder downstream from a final polycondensation stage and optionally mixing said at least one phosphine of formula (I), said at least one carboxylic ester, and said melt polycarbonate in a static mixer.

2. The process of claim 1 , further comprising at least one alkyl phosphate.

3. The process of claim 1 , wherein said melt polycarbonate comprises a compound of formula (IV)

wherein

the square bracket indicates repeating structural units,

Y is H or a group of formula (X)

wherein

R 16 , is, identically or differently, H, C 1 to C 20 -alkyl, C 6 H 5 , or C(CH 3 ) 2 C 6 H 5 , and

u is 0, 1, 2, or 3,

M is Ar or a polyfunctional group A, B, or C, or a group D,

wherein

Ar is a group of formula (VIII) or (IX),

wherein

Z is C 1 to C 8 -alkylidene, C 5 to C 12 -cycloalkylidene, S, SO 2 , or a single bond,

R 13 , R 14 , and R 15

are independently of the others a substituted or unsubstituted C 1 -C 18 alkyl moiety, preferably substituted or unsubstituted phenyl, methyl, propyl, ethyl, butyl, Cl or Br,

r, s, and t

are, independently of one another, 0, 1, or 2,

the polyfunctional group A is a group of formula

the polyfunctional group B is a group of formula

the polyfunctional group C is a group of formula

wherein

X is Y or -[MOCOO] n —Y, wherein M and Y are as defined above,

group D is a group of formula

and the entirety of polyfunctional groups A, B, C and D is ≧5 mg/kg.

4. The process of claim 1 , wherein said at least one phosphine of formula (I) is a compound of formula (I), the oxidic form thereof, or a mixture thereof.

5. The process of claim 1 , wherein said at least one phosphine of formula (I) is triphenylphosphine, the oxidic form thereof, or a mixture thereof.

6. The process of claim 1 , wherein up to 80% of said at least one phosphine of formula (I) is in its oxidic form.

7. The process of claim 2 , wherein said at least one alkyl phosphate is of formula (II):

wherein

R 1 , R 2 , and R 3 are identically or differently H or a linear, branched, or cyclic alkyl group.

8. The process of claim 7 , wherein said at least one alkyl phosphate comprises at least one of mono-, di-, or triisooctyl phosphate (tris-2-ethylhexyl phosphate).

9. The process of claim 1 , wherein said at least one aliphatic carboxylic ester is a compound of formula (III):

(R 4 —CO—O) o —R 5 —(OH) p where o=1 to 4 and p=3 to 0  (III)

wherein

R 4 is an aliphatic saturated or unsaturated, linear, cyclic or branched alkyl moiety and R 5 is an alkylene moiety of a mono- to tetrahydric aliphatic alcohol R 5 —(OH) o+p .

10. The process of claim 1 , wherein said at least one aliphatic carboxylic ester comprises esters of pentaerythritol, glycerol, trimethylolpropane, propanediol, stearyl alcohol, cetyl alcohol, or myristyl alcohol with myristic, palmitic, stearic, or montanic acid, or mixtures thereof.

11. The process of claim 1 , wherein said at least one phosphine of formula (I) is used in an amount of from 10 to 2000 mg/kg based on the total weight of said composition.

12. The process of claim 2 , wherein said at least one alkyl phosphate is used in an amount of from 0.5 to 500 mg/kg based on the total weight of said composition.

13. The process of claim 1 , wherein said at least one aliphatic carboxylic ester is used in an amount of from 50 to 8000 mg/kg based on the total weight of said composition.

14. The process of claim 1 , comprising producing said melt polycarbonate via a melt transesterification reaction of a bisphenol and a carbonic diester.

15. The process of claim 1 , comprising producing said melt polycarbonate via condensation of a carbonate oligomer containing hydroxy and/or carbonate end groups, a bisphenol, and a carbonic diester.

16. The process of claim 1 , comprising metering said at least one carboxylic ester using a membrane pump into the melt stream of said melt polycarbonate downstream from an ancillary extruder and upstream from a static mixer.