SILOXANE-CONTAINING BLOCK COPOLYCARBONATES HAVING A SMALL DOMAIN SIZE

Abstract

The present invention relates to a method for preparing a polysiloxane-polycarbonate block co-condensate, wherein a siloxane component containing both aliphatic and aromatic groups is used as a mediator. The invention also relates to a polycarbonate composition and also to the use of the special siloxane component for reducing the particle size distribution of the siloxane domains in a polysiloxane-polycarbonate block co-condensate.

Claims

1.-15. (canceled)

16. A polycarbonate composition containing (i) at least one polysiloxane-polycarbonate block co-condensate, (ii) at least one siloxane of general chemical formula (I), (Ia) or any desired mixtures thereof, ##STR00023## in which Z.sub.1, Z.sub.2 and Z.sub.3 each independently of one another represent methyl, ethyl, propyl, butyl, isopropyl, isobutyl, vinyl, propenyl, butenyl, C5 to C18 alkyl, methacryloxypropyl; monodicarbinol, methoxy, ethoxy, propoxy, butoxy, epoxypropoxypropyl, optionally alkyl- or alkoxy-substituted phenylethyl, phenylisopropyl, 3-phenylpropyl or phenyl, hydroxy, hydrogen, chlorine, fluorine or CN, R.sub.8 and R.sub.9 each independently of one another represent an aliphatic or an aromatic group with the proviso that in the formula (I) or (Ia) at least one R.sub.8 represents an aliphatic group and at least one R.sub.9 represents an aromatic group and s, s.sub.1, s.sub.2, s.sub.3 and s.sub.4 each independently of one another represent a natural number between 1 and 250, (iii) optionally at least one further polymer distinct from component (i) and (iv) optionally at least one further additive.

17. The polycarbonate composition as claimed in claim 16, wherein R.sub.8 in general chemical formula (I) or (Ia) independently at each occurrence represents methyl, ethyl, propyl, butyl, isopropyl, isobutyl, vinyl, C5 to C18-alkyl or optionally alkyl- or alkoxy-substituted phenylethyl, phenylisopropyl, 3-phenylpropyl or phenyl, R.sub.9 in general chemical formula (I) or (Ia) independently at each occurrence represents methyl, ethyl, propyl, butyl, isopropyl, isobutyl, vinyl, C5 to C18-alkyl or optionally alkyl- or alkoxy-substituted phenylethyl, phenylisopropyl, 3-phenylpropyl or phenyl, with the proviso that at least one R.sub.8 represents methyl, ethyl, propyl, butyl, isopropyl, vinyl, isobutyl or C5 to C18-alkyl and at least one R.sub.9 represents optionally alkyl- or alkoxy-substituted phenylethyl, phenylisopropyl, 3-phenylpropyl or phenyl and Z.sub.1, Z.sub.2 and Z.sub.3 in general chemical formula (I) or (Ia) each independently of one another have the definitions recited in claim 16.

18. The polycarbonate composition as claimed in claim 17, wherein R.sub.8 in general chemical formula (I) or (Ia) independently at each occurrence represents methyl, ethyl, trimethylphenyl, —CH.sub.2—CH.sub.2-phenyl, —CH.sub.2—CH.sub.2—CH.sub.2-phenyl, —CH.sub.2—CH(CH.sub.3)-phenyl, —CH.sub.2—CH.sub.2—CH.sub.2-(2-methoxy)phenyl or phenyl and R.sub.9 in general chemical formula (I) or (Ia) independently at each occurrence represents methyl, ethyl, trimethylphenyl, —CH.sub.2—CH.sub.2-phenyl, —CH.sub.2—CH.sub.2—CH.sub.2-phenyl, —CH.sub.2—CH(CH.sub.3)-phenyl, —CH.sub.2—CH.sub.2—CH.sub.2-(2-methoxy)phenyl or phenyl, with the proviso that at least one R.sub.8 represents methyl or ethyl and at least one R.sub.9 represents trimethylphenyl or phenyl and Z.sub.1, Z.sub.2 and Z.sub.3 in general chemical formula (I) or (Ia) each independently of one another have the definitions recited in claim 16.

19. The polycarbonate composition as claimed in claim 16, wherein the at least one siloxane of component (ii) is represented by general chemical formula (II), general chemical formula (IIa), general chemical formula (III) and/or general chemical formula (IV) ##STR00024## in which Z.sub.1, Z.sub.2 and Z.sub.3 each independently of one another represent methyl, ethyl, propyl, butyl, isopropyl, isobutyl, vinyl, propenyl, butenyl, C5 to C18 alkyl, methacryloxypropyl; monodicarbinol, methoxy, ethoxy, propoxy, butoxy, epoxypropoxypropyl, optionally alkyl- or alkoxy-substituted phenylethyl, phenylisopropyl, 3-phenylpropyl or phenyl, hydroxy, hydrogen, chlorine, fluorine or CN, R.sub.10 independently at each occurrence represents hydrogen, methyl, ethyl, propyl, butyl, isopropyl, isobutyl, isooctyl, isononyl or isodecyl, R.sub.11 independently at each occurrence represents methyl, ethyl, propyl, butyl, isopropyl, isobutyl, vinyl, propenyl, butenyl, C5 to C18 alkyl, methacryloxypropyl; monodicarbinol, methoxy, ethoxy, propoxy, butoxy, epoxypropoxypropyl, optionally alkyl- or alkoxy-substituted phenylethyl, phenylisopropyl, 3-phenylpropyl or phenyl, hydroxy, hydrogen, chlorine, fluorine or CN, r is a natural number between 0 and 3, s and t are each independently of one another a natural number between 1 and 250, and w and v are each independently of one another a natural number between 1 and 250, and groups having the indices s, w, v, t and u can have a random distribution in the siloxane of component (ii).

20. The polycarbonate composition as claimed in claim 19, wherein in general chemical formulae (II), (IIa), (III) and (IV) Z.sub.1, Z.sub.2 and Z.sub.3 each independently of one another represent methyl, vinyl, methoxy, ethoxy, hydrogen or hydroxy, R.sub.10 represents hydrogen or methyl, R.sub.11 independently at each occurrence represents methyl, ethyl, propyl, butyl, isopropyl, isobutyl, vinyl, propenyl, butenyl, C5 to C18 alkyl, methacryloxypropyl; monodicarbinol, methoxy, ethoxy, propoxy, butoxy, epoxypropoxypropyl, optionally alkyl- or alkoxy-substituted phenylethyl, phenylisopropyl, 3-phenylpropyl or phenyl, hydroxy, hydrogen, chlorine, fluorine or CN, r is a natural number between 0 and 3, s is a natural number between 5 and 75, t is a natural number between 1 and 75, w is a natural number between 5 and 75, v is a natural number between 1 and 75 and u is a natural number between 1 and 10.

21. A process for producing polysiloxane-polycarbonate block co-condensates, wherein A) at least one polycarbonate is reacted in the melt with B) at least one hydroxyaryl-terminated (poly)siloxane using C) at least one siloxane of general chemical formula (I), (Ia) or any desired mixtures thereof, ##STR00025## in which Z.sub.1, Z.sub.2 and Z.sub.3 each independently of one another represent methyl, ethyl, propyl, butyl, isopropyl, isobutyl, vinyl, propenyl, butenyl, C5 to C18 alkyl, methacryloxypropyl; monodicarbinol, methoxy, ethoxy, propoxy, butoxy, epoxypropoxypropyl, optionally alkyl- or alkoxy-substituted phenylethyl, phenylisopropyl, 3-phenylpropyl or phenyl, hydroxy, hydrogen, chlorine, fluorine or CN, R.sub.8 and R.sub.9 each independently of one another represent an aliphatic or an aromatic group with the proviso that in the formula (I) or (Ia) at least one R.sub.8 represents an aliphatic group and at least one R.sub.9 represents an aromatic group and s, s.sub.1, s.sub.2, s.sub.3 and s.sub.4 each independently of one another represent a natural number between 1 and 250, wherein the process comprises a step of adding the component C) to the component A), to the component B) and/or to a mixture of component A) and B).

22. The process for producing polysiloxane-polycarbonate block co-condensates as claimed in claim 21, wherein wherein component B) is a hydroxyaryl-terminated (poly)siloxane of formula (1), ##STR00026## wherein R.sup.5 represents hydrogen or C1 to C4 alkyl, R.sup.6 and R.sup.7 independently of one another represent C1 to C4 alkyl, Y represents a single bond, —CO—, —O—, C.sub.1- to C.sub.5-alkylene, C.sub.2- to C.sub.5-alkylidene or a C.sub.5- to C.sub.6-cycloalkylidene radical which may be mono- or polysubstituted by C.sub.1- to C.sub.4-alkyl, V represents oxygen, C2-C6 alkylene or C3- to C6-alkylidene, when q=0, W represents a single bond, when q=1, W represents oxygen, C2 to C6-alkylene or C3- to C6-alkylidene, p and q are each independently 0 or 1, o represents an average number of repeating units from 10 to 400, and m represents an average number of repeating units from 1 to 10.

23. The process for producing polysiloxane-polycarbonate block co-condensates as claimed in claim 21, wherein component B) is a hydroxyaryl-terminated (poly)siloxane of formulae (2), (3), (VII), (VIII) or (IX): ##STR00027## wherein R1 represents hydrogen, C1-C4-alkyl, R2 independently represents aryl or alkyl, X represents a single bond, C1 to C5-alkylene, C2 to C5-alkylidene, C5 to C12-cycloalkylidene, —O—, —SO— —CO—, —S—, —SO.sub.2—, isopropylidene, C5 to C12 cycloalkylidene or oxygen, n is a number between 10 and 150, m is a number from 1 to 10, ##STR00028## wherein a in formulae (VII), (VIII) and (IX) represents an average number from 10 to 400.

24. The process for producing polysiloxane-polycarbonate block co-condensates as claimed in claim 21, wherein R.sub.8 in general chemical formula (I) or (Ia) independently at each occurrence represents methyl, ethyl, propyl, butyl, isopropyl, isobutyl, vinyl, C5 to C18-alkyl or optionally alkyl- or alkoxy-substituted phenylethyl, phenylisopropyl, 3-phenylpropyl or phenyl and R.sub.9 in general chemical formula (I) or (Ia) independently at each occurrence represents methyl, ethyl, propyl, butyl, isopropyl, isobutyl, vinyl, C5 to C18-alkyl or optionally alkyl- or alkoxy-substituted phenylethyl, phenylisopropyl, 3-phenylpropyl or phenyl, with the proviso that at least one R.sub.8 represents methyl, ethyl, propyl, butyl, isopropyl, vinyl, isobutyl or C5 to C18-alkyl and at least one R.sub.9 represents optionally alkyl- or alkoxy-substituted phenylethyl, phenylisopropyl, 3-phenylpropyl or phenyl.

25. The process for producing polysiloxane-polycarbonate block co-condensates as claimed in claim 21, wherein R.sub.8 in general chemical formula (I) or (Ia) independently at each occurrence represents methyl, ethyl, trimethylphenyl, —CH.sub.2—CH.sub.2-phenyl, —CH.sub.2—CH.sub.2—CH.sub.2-phenyl, —CH.sub.2—CH(CH.sub.3)-phenyl, —CH.sub.2—CH.sub.2—CH.sub.2-(2-methoxy)phenyl or phenyl and R.sub.9 in general chemical formula (I) or (Ia) independently at each occurrence represents methyl, ethyl, trimethylphenyl, —CH.sub.2—CH.sub.2-phenyl, —CH.sub.2—CH.sub.2—CH.sub.2-phenyl, —CH.sub.2—CH(CH.sub.3)-phenyl, —CH.sub.2—CH.sub.2—CH.sub.2-(2-methoxy)phenyl or phenyl, with the proviso that at least one R.sub.8 represents methyl or ethyl and at least one R.sub.9 represents trimethylphenyl or phenyl.

26. The process for producing polysiloxane-polycarbonate block co-condensates as claimed in claim 21, wherein the at least one siloxane of component C) is represented by general chemical formula (II), general chemical formula (IIa), general chemical formula (III) and/or general chemical formula (IV) ##STR00029## in which Z.sub.1, Z.sub.2 and Z.sub.3 each independently of one another represent methyl, ethyl, propyl, butyl, isopropyl, isobutyl, vinyl, propenyl, butenyl, C5 to C18 alkyl, methacryloxypropyl; monodicarbinol, methoxy, ethoxy, propoxy, butoxy, epoxypropoxypropyl, optionally alkyl- or alkoxy-substituted phenylethyl, phenylisopropyl, 3-phenylpropyl or phenyl, hydroxy, hydrogen, chlorine, fluorine or CN, R.sub.10 independently at each occurrence represents hydrogen, methyl, ethyl, propyl, butyl, isopropyl, isobutyl, isooctyl, isononyl or isodecyl, R.sub.11 independently at each occurrence represents methyl, ethyl, propyl, butyl, isopropyl, isobutyl, vinyl, propenyl, butenyl, C5 to C18 alkyl, methacryloxypropyl; monodicarbinol, methoxy, ethoxy, propoxy, butoxy, epoxypropoxypropyl, optionally alkyl- or alkoxy-substituted phenylethyl, phenylisopropyl, 3-phenylpropyl or phenyl, hydroxy, hydrogen, chlorine, fluorine or CN, r is a natural number between 0 and 3, s and t are each independently a natural number between 1 and 250, w and v are each independently a natural number between 1 and 250, and groups having the indices s, w, v, t and u can have a random distribution in the siloxane of component C).

27. The process for producing polysiloxane-polycarbonate block co-condensates as claimed in claim 26, wherein in general chemical formulae (II), (IIa), (III) and (IV) Z.sub.1, Z.sub.2 and Z.sub.3 each independently of one another represent methyl, vinyl, methoxy, ethoxy, hydrogen or hydroxy, R.sub.10 represents hydrogen or methyl, R.sub.11 independently at each occurrence represents methyl, ethyl, propyl, butyl, isopropyl, isobutyl, vinyl, propenyl, butenyl, C5 to C18 alkyl, methacryloxypropyl; monodicarbinol, methoxy, ethoxy, propoxy, butoxy, epoxypropoxypropyl, optionally alkyl- or alkoxy-substituted phenylethyl, phenylisopropyl, 3-phenylpropyl or phenyl, hydroxy, hydrogen, chlorine, fluorine or CN, r is a natural number between 0 and 3, s is a natural number between 5 and 75, t is a natural number between 1 and 75, w is a natural number between 5 and 75 and v is a natural number between 1 and 75.

28. The process for producing polysiloxane-polycarbonate block co-condensates as claimed in claim 21, wherein 0.01% to 20% by weight of the component C) are added to the component A), to the component B) and/or to a mixture of component A) and B), wherein the % by weight values are based on the sum of the components A), B) and C).

29. The use of a siloxane of general chemical formula (I), (Ia) or any desired mixtures thereof, ##STR00030## in which Z.sub.1, Z.sub.2 and Z.sub.3 each independently of one another represent methyl, ethyl, propyl, butyl, isopropyl, isobutyl, vinyl, propenyl, butenyl, C5 to C18 alkyl, methacryloxypropyl; monodicarbinol, methoxy, ethoxy, propoxy, butoxy, epoxypropoxypropyl, optionally alkyl- or alkoxy-substituted phenylethyl, phenylisopropyl, 3-phenylpropyl or phenyl, hydroxy, hydrogen, chlorine, fluorine or CN, R.sub.8 and R.sub.9 each independently of one another represent an aliphatic or an aromatic group with the proviso that in the formula (I) or (Ia) at least one R.sub.8 represents an aliphatic group and at least one R.sub.9 represents an aromatic group and s, s.sub.1, s.sub.2, s.sub.3 and s.sub.4 each independently of one another represent a natural number between 1 and 250, for reducing the particle size distribution of the siloxane domains in a polysiloxane-polycarbonate block co-condensate in a process for producing this polysiloxane-polycarbonate block co-condensate.

30. The use as claimed in claim 29, wherein the process for producing the polysiloxane-polycarbonate block co-condensate comprises at least one reactive extrusion or at least one melt transesterification.

Description

WORKING EXAMPLES

[0269] There follows a detailed description of the invention with reference to working examples, and the methods of determination described here are employed for all corresponding parameters in the present invention, in the absence of any statement to the contrary.

[0270] MVR

[0271] Unless stated otherwise, the melt volume flow rate (MVR) is determined according to ISO 1133 (2011) (at 300° C.; 1.2 kg), unless any other conditions are stated.

[0272] Solution Viscosity

[0273] Determination of solution viscosity: The solution viscosity (ηrel; also referred to as the relative solution viscosity) was determined using an Ubbelohde viscometer in dichloromethane at a concentration of 5 g/l at 25° C.

[0274] Evaluation of the Siloxane Domain Size Using Atomic Force Microscopy (AFM)

[0275] The siloxane domain size and distribution were determined using atomic force microscopy. To this end the corresponding sample (in the form of a melt cake for laboratory batches or granulate for extrusion batches) was cut at low temperature (nitrogen cooling) using an ultramicrotome. A Bruker D3100 AFM microscope was used. The AFM image was recorded at room temperature (25° C., 30% relative humidity). The “Soft Intermittent Contact Mode” or “Tapping Mode” were used for the measurement. A “tapping mode cantilever” (Nanoworld pointprobe) having a spring constant of about 2.8 Nm-1 and a resonance frequency of about 75 kHz was used to scan the sample. The tapping force is controlled by the ratio of the target amplitude and the free oscillation amplitude (amplitude of the probe tip with free oscillation in air). The sampling rate was set to 1 Hz. To record the surface morphology phase contrast and topography images were recorded on a 2.5 μm×2.5 μm area. The particles/siloxane domains were evaluated automatically using Olympus SIS image processing software (Olympus Soft Imaging Solutions GmbH, 48149, Munster, Germany) via light-dark contrast (from the phase contrast images). The diameters of the particles were determined from the diameter of the corresponding equal area circle of the longest dimension of the particle.

[0276] A plurality of phase contrast images (number of particles greater than 200) are evaluated as described above. The image processing software is used to classify the individual diameters and capture a distribution of the diameters. This is used for assignment to individual D values. The D value indicates the proportion of particles smaller than the specified value. At a D90 value of x 90% of the particles are smaller than x. The proportion of particles smaller than 100 nm is also determined from the distribution.

[0277] Effect of Adding Component C)

[0278] Starting Materials:

[0279] Component A: Polycarbonate

[0280] PC 1: The starting material used for the reactive extrusion is linear bisphenol A polycarbonate having end groups based on phenol and a solution viscosity of 1.17 (see above for description). This polycarbonate contains no additives such as UV stabilizers, mold release agents or thermal stabilizers. The polycarbonate was produced by a melt transesterification process as described in DE 102008019503. The polycarbonate has a content of phenolic end groups of 0.16%.

[0281] Component B: Siloxane

[0282] Bisphenol A-terminated polydimethylsiloxane of formula 3 where n is about 30 and m is in the range from 3 to 4 (R.sup.1═H, R.sup.2=methyl, X=isopropylidene) having a hydroxy content of 18 mg KOH/g and a viscosity of 400 mPa.Math.s (23° C.); the siloxane is admixed with sodium octanoate and the sodium content is 2.5 ppm.

[0283] Component C/(ii):

[0284] Linear oligomeric siloxane of formula (I) where Z.sub.1 and Z.sub.2═OH, R.sub.8=methyl, R.sub.9=phenyl and s is on average about 4 (oligomeric mixture with chains of s=2 to about 10).

[0285] Process:

[0286] The scheme of the experimental setup is apparent from FIG. 1.

[0287] FIG. 1 shows a scheme for producing the siloxane-containing block co-condensates. Polycarbonate (component A) is metered into the twin-screw extruder (1) via the gravimetric feed (2). The extruder (ZSE 27 MAXX from Leistritz Extrusionstechnik GmbH, Nuremberg) is a co-rotating twin-screw extruder with vacuum zones for removal of the vapors. The extruder consists of 11 barrel sections (a to k)—see FIG. 1. Addition of polycarbonate is carried out in barrel section a via the differential metering balance (2) and the melting of the polycarbonate is carried out in barrels b and c. Addition of the liquid siloxane component (component B) is effected in barrel section d. Barrel sections d and e are also used for incorporating the liquid siloxane component (component B). Barrel sections e, g, i and j are provided with degassing openings to remove the condensation products. Barrel section e is assigned to the first vacuum stage and barrel sections g, i and j are assigned to the second vacuum stage. The vacuum in the first vacuum stage is between 45 and 65 mbar absolute pressure. The vacuum in the second vacuum stage is less than 1 mbar. The siloxane (component B) is initially charged in a tank (3) and introduced into the extruder via a metering pump (4). The vacuum is generated via vacuum pumps (5) and (6). The vapors are conducted away from the extruder and collected in 2 condensers (9). The melt strand is passed into a water bath (10) and comminuted by the granulator (11).

Example 1

[0288] For preparation, polycarbonate (component A) was mixed with 0.5% of component C in a solids mixer. 1.9 kg/h of polycarbonate (component A) were metered into the twin-screw extruder (1) via the gravimetric metered addition means (2). The speed of the extruder was set to 120 rpm. 0.09 kg/h of component B were introduced into the barrel (d) of the extruder via the pump (4). A vacuum of 55 mbar was applied to the barrel (e) and a vacuum of 0.5 mbar was applied to each of the barrels (g), (i) and (j). The barrels (g) to (k) were brought to a temperature of 350° C.

[0289] The resulting polycondensate was light in color and had an MVR of 2.1. An AFM image measuring 10×10 μm contained 880 identified objects that were assignable to a soft phase and thus to the siloxane phase. The size distribution of the objects had a D90 diameter of 115 nm. The largest identified object corresponded to an equivalent circle diameter of 156 nm.

Comparative Example 2

[0290] 1.9 kg/h of polycarbonate (component A) were metered into the twin-screw extruder (1) via the gravimetric metered addition means (2). The speed of the extruder was set to 120 rpm. 0.09 kg/h of component B were introduced into the barrel (d) of the extruder via the pump (4). A vacuum of 63 mbar was applied to the barrel (e) and a vacuum of 0.5 mbar was applied to each of the barrels (g), (i) and (j). The barrels (g) to (k) were brought to a temperature of 325° C.

[0291] The resulting polycondensate was light in color and had an MVR of 4.4. An AFM image measuring 10×10 μm contained 624 identified objects that were assignable to a soft phase and thus to the siloxane phase. The size distribution of the objects had a D90 diameter of 185 nm. The largest identified object corresponded to an equivalent circle diameter of 516 nm.

[0292] The following examples were carried out in the manner of example 1/comparative example 2 with variation of the reported parameters:

TABLE-US-00001 TABLE 1 Component Extruder Through- Barrel C) [% by speed put temperature weight] [rpm] [kg/h] [° C.] MVR Comparative — 120 2.0 320 6.8 example 3 Example 4 0.5 180 2.0 310 8.5 Comparative — 120 2.0 325 4.4 example 5 Example 6 0.5 120 2.0 350 2.1 Comparative — 120 1.42 320 9.5 example 7 Example 8 1.0 120 1.05 320 5.6 Example 9 0.5 120 1.42 320 8.1

[0293] As is apparent from this table comparative example 3 and example 4 are essentially comparable with one another. Polymers having a comparable MVR are obtained despite the use of a slightly different extruder speed and barrel temperature. The examples thus differ in terms of the addition of component C) in example 4 and the absence thereof in comparative example 3.

[0294] Similar conclusions can be drawn for the comparability of comparative example 5 and example 6 and of comparative example 7 and examples 8 and 9. The comparisons are suitable for evaluating the effect of adding component C) (and also the amount thereof).

TABLE-US-00002 TABLE 2 Domain distribution results Particle size Content of Volume distribution; D90 particles fraction of of average particle <100 nm particles diameter [nm] [%] <200 nm [%] Comparative example 3 124.9 75.3 84.9 Example 4 105.9 87.6 88.3 Comparative example 5 184.7 54.2 49.9 Example 6 115.0 80.0 100.0 Comparative example 7 101.2 88.7 25.0 Example 8 91.0 94.5 100.0 Example 9 98.8 90.3 61.0

[0295] In the case of throughputs of 2.0 kg/h and materials having an MVR in the range from about 7 to 9 (comparative example 3 and example 4) inventive example 4 shows the positive effect of the low molecular weight siloxane according to the invention. Compared to the comparative example 3 inventive example 4 has a markedly lower D 90 value and thus provides a polymer morphology having a lower siloxane domain size. Increasing the reaction temperature makes it possible to achieve lower viscosities (comparative example 5 and example 6). Inventive example 6, which contains the low molecular weight inventive siloxane addition of component C), shows a markedly lower D90 value than comparative example 5.

[0296] The positive effect of adding the special siloxane component is likewise apparent at relatively low throughputs (1.4 kg or less compared to 2.0 kg/h). While comparative example 7 exhibits a similar D90 value to inventive example 9 the proportion of particles having a volume <200 nm is markedly greater than in inventive example 9. Particles having a large volume are particularly critical in terms of processing defects, for example in injection molding. Increasing the proportion of the inventive siloxane component (example 8) achieves further advantages as is apparent from the lower D90 value and from a better volume distribution (particles having a volume >200 nm are no longer present).

[0297] Effect of Chemical Structure of Component C)

[0298] Starting Materials:

[0299] Component A: Polycarbonate

[0300] PC A: The starting material used for the reactive extrusion is linear bisphenol A polycarbonate having end groups based on phenol from Covestro Deutschland AG which has a melt volume index of 59-62 cm.sup.3/10 min measured at 300° C. and a load of 1.2 kg (according to ISO 1033). This polycarbonate contains no additives such as UV stabilizers, mold release agents or thermal stabilizers. The polycarbonate was produced by a melt transesterification process as described in DE 102008019503. The polycarbonate has a content of phenolic end groups of about 600 ppm.

[0301] PC B: The starting material used for the reactive extrusion is linear bisphenol A polycarbonate having end groups based on phenol and a solution viscosity of about 1.17. This polycarbonate contains no additives such as UV stabilizers, mold release agents or thermal stabilizers. The polycarbonate was produced by a melt transesterification process as described in DE 102008019503. The polycarbonate has a content of phenolic end groups of about 1600 ppm.

[0302] Component B:

[0303] Siloxane 1

[0304] Bisphenol A-terminated polydimethylsiloxane of formula 3 where n is about 15 and m is in the range from 3 to 4 (R.sup.1═H, R.sup.2=methyl, X=isopropylidene) having a hydroxy content of 27.8 mg KOH/g and a viscosity of 165 mPa.Math.s (23° C.); the sodium content is about 4 ppm.

[0305] Siloxane 2:

[0306] Hydroquinone-terminated polydimethylsiloxane of formula 2 where n is about 20 and m is in the range from 3 to 4 (R.sup.1═H, R.sup.2=methyl) having a hydroxy content of 22.2 mg KOH/g and a viscosity of 177 mPa.Math.s (23° C.); the sodium content is about 3 ppm.

[0307] Siloxane 3:

[0308] Bisphenol A-terminated polydimethylsiloxane of formula 3 where n is about 30 and m is in the range from 3 to 4 (R.sup.1═H, R.sup.2=methyl, X=isopropylidene) having a hydroxy content of 17.9 mg KOH/g and a viscosity of 402 mPa.Math.s (23° C.); the sodium content is about 3 ppm.

[0309] Component C/(ii):

[0310] Linear oligomeric siloxane of formula (I) where Z.sub.1 and Z.sub.2═OH, R.sub.8=methyl, R.sub.9=phenyl and s is on average about 4 (oligomeric mixture with chains of s=2 to about 10).

[0311] Comparative Component:

[0312] Octaphenylcyclotetrasiloxane (CAS: 546-56-5), 95% from ABCR GmbH & Co.KG (Karlsruhe Germany).

[0313] Catalyst Masterbatch (without Siloxane-Based Additional Component):

[0314] The catalyst used is tetraphenylphosphonium phenoxide from Rhein Chemie Rheinau GmbH (Mannheim, Germany) in the form of a masterbatch. Tetraphenylphosphonium phenoxide was employed in the form of a solid solution with phenol and contains about 70% tetraphenylphosphonium phenoxide. The amounts which follow are based on the substance obtained from Rhein Chemie (as solid solution with phenol).

[0315] The masterbatch was produced as a 0.25% mixture. To this end 4982 g of Polycarbonate PC A were mixed with 18 g of tetraphenylphosphonium phenoxide in a drum hoop mixer for 30 minutes. Metered addition of the masterbatch was carried out in a ratio of 1:10 and the catalyst was therefore present in the total amount of polycarbonate in a proportion of 0.025% by weight.

Comparative Example 10

[0316] Weighed into a 250 ml glass flask fitted with a stirrer and short path separator were 42.5 g of polycarbonate granulate (PC A; 85% by weight), 2.5 g of siloxane 1 (5% by weight) as well as 5 g (10% by weight) of catalyst masterbatch and 0.1 g (0.2% by weight) of octaphenylcyclotetrasiloxane. The apparatus was evacuated and inertized with nitrogen (3× in each case). The mixture was melted under vacuum over 10 minutes using a metal bath preheated to 350° C. The pressure in the apparatus was about 1.5 mbar. The reaction mixture was kept under this vacuum with stirring for 30 minutes. The mixture was subsequently inertized with nitrogen and the polymer melt withdrawn. An opaque white polymer was obtained. The product has a solution viscosity eta rel=1.345.

Comparative Example 11

[0317] Weighed into a 250 ml glass flask fitted with a stirrer and short path separator were 42.5 g of polycarbonate granulate (PC A; 85% by weight), 2.5 g of siloxane 2 (5% by weight) as well as 5 g (10% by weight) of catalyst masterbatch (in a departure from the above this further contained 1.66% by weight of octaphenylcyclotetrasiloxane). The apparatus was evacuated and inertized with nitrogen (3× in each case). The mixture was melted under vacuum over 10 minutes using a metal bath preheated to 350° C. The pressure in the apparatus was about 1.5 mbar. The reaction mixture was kept under this vacuum with stirring for 30 minutes. The mixture was subsequently inertized with nitrogen and the polymer melt withdrawn. An opaque white polymer was obtained. The product has a solution viscosity eta rel=1.46.

Example 12

[0318] 47.4 g of polycarbonate granulate (PC B; 94.8% by weight) were weighed into a 250 ml glass flask fitted with a stirrer and short path separator. The apparatus was evacuated and inertized with nitrogen (3× in each case). The mixture was melted under atmospheric pressure over 10 minutes using a metal bath preheated to 350° C. A siloxane mixture composed of 2.5 g of siloxane 3 (5% by weight) and 0.13 g (0.2% by weight) of component C (dissolved in siloxane 3) was added at 10 mbar. The pressure in the apparatus was then reduced to about 1.5 mbar. The reaction mixture was kept under this vacuum with stirring for about 5 minutes. The mixture was subsequently inertized with nitrogen and the polymer melt withdrawn. An opaque white polymer was obtained. The product has a solution viscosity eta rel=1.38.

TABLE-US-00003 TABLE 3 Domain distribution results Particle size distribution; Content of particles D90 of average <100 nm particle diameter [nm] [%] Example 12 110.4 85.3

[0319] Comparative examples 10 and 11 showed a clearly coarse particle distribution in the AFM; an exact evaluation was therefore eschewed and only an estimate was made.

TABLE-US-00004 TABLE 4 Domain distribution results Large particle Small particle diameter diameter (40 μm image) [nm] (2.5 μm image) [nm] Comparative example 10 1700 (elongate) 20-270 (round) Comparative example 11 1000 (elongate) 26-240 (round)

[0320] Comparison of example 12 with comparative examples 10 and 11 shows that the addition of a compound comprising both aliphatic and aromatic groups results in a reduced siloxane domain distribution in the production of a polysiloxane-polycarbonate block co-condensate compared to a compound comprising only aromatic groups.