Stabilized, filled polycarbonate compositions

Abstract

The invention relates to the use of PMMI copolymers for reducing the molecular weight degradation of the polymer induced by oxides such as titanium dioxide or silicon dioxide in compositions based on aromatic polycarbonate. The mechanical, optical and rheological properties of the thermoplastic composition remain good and are in some cases even improved despite the addition of the PMMI copolymer.

Claims

1. A composition containing A) aromatic polycarbonate, B) one or more oxides of metals or metalloids of the 3rd main group, 4th main group and/or 4th transition group, wherein the proportion of oxides of metals or metalloids of the 3rd main group, 4th main group and/or 4th transition group is 15% to 25% by weight based on the total composition and the ratio of oxides of metals or metalloids of the 3rd main group, 4th main group and/or 4th transition group to PMMI copolymer is ≤40, C) PMMI copolymer and D) optionally further additives.

2. The composition according to claim 1, wherein the composition contains A) at least 55% by weight of aromatic polycarbonate, B) 5% to 44% by weight of one or more oxides of metals or metalloids of the 3rd main group, 4th main group and/or 4th transition group, C) 0.1% to 8% by weight of PMMI copolymer and D) optionally further additives.

3. The composition according to claim 1, wherein the composition contains A) at least 56% by weight of aromatic polycarbonate, B) 10% to 35% by weight of one or more oxides of metals or metalloids of the 3rd main group, 4th main group and/or 4th transition group, C) 0.2% to 6% by weight of PMMI copolymer and D) optionally further additives.

4. The composition according to claim 1, consisting of A) at least 60% by weight of aromatic polycarbonate, B) 10% to 30% by weight of one or more oxides of metals or metalloids of the 3rd or 4th main group or 4th transition group, C) 0.2% to 6% by weight of PMMI copolymer and D) optionally one or more further additives distinct from components B and C selected from the group consisting of flame retardants, anti-drip agents, impact modifiers, fillers, antistats, colourants, pigments, carbon black, lubricants and/or demoulding agents, heat stabilizers, blend partners, compatibilizers, UV absorbers and/or IR absorbers.

5. The composition according to claim 1, wherein the composition contains at least 1.5% by weight of PMMI copolymer, based on the overall composition.

6. The composition according to claim 1, wherein the composition contains at least 1.0% by weight of PMMI copolymer.

7. The composition according to claim 1, wherein the PMMI copolymer has methyl methacrylate units, methylmethacrylimide units, methylmethacrylic acid units and methylmethacrylic anhydride units.

8. The composition according to claim 1, wherein the proportion of methylmethacrylimide units is at least 30% by weight, the proportion of methyl methacrylate units is 3% to 65% by weight and the proportion of methylmethacrylic acid and methylmethacrylic anhydride units is in total up to 15% by weight in each case based on the total weight of the PMMI copolymer present in the composition.

9. The composition according to claim 1, wherein the acid number of the PMMI copolymer, determined according to DIN 53240-1:2013-06, is 15 to 50 mg KOH/g.

10. The composition according to claim 1, wherein the proportion of PMMI copolymer in the composition is 2% to 6% by weight.

11. A moulding made from or comprising regions of a composition according to claim 1.

12. The moulding according to claim 11 wherein the moulding is selected from the group consisting of a profile, a plate, a housing part in the electricals/electronics sector, a heatsink, a reflector, a printed circuit board in the electronics sector, an element for an optical application, and a composite.

13. A method comprising providing a polycarbonate composition comprising at least one PMMI copolymer and one or more oxides of metals or metalloids of the 3rd main group, 4th main group and/or 4th transition group during compounding, wherein the proportion of oxides of metals or metalloids of the 3rd main group, 4th main group and/or 4th transition group is 15% to 25% by weight based on the total composition and the ratio of oxides of metals or metalloids of the 3rd main group, 4th main group and/or 4th transition group to PMMI copolymer is ≤40, and reducing the molecular weight degradation of aromatic polycarbonate in the composition.

14. The method according to claim 13, wherein the PMMI copolymer has 3% to 65% by weight of methyl methacrylate units, at least 30% by weight of methylmethacrylimide units, a total of up to 15% by weight of methylmethacrylic acid units and methylmethacrylic anhydride units, in each case based on the total weight of the PMMI copolymer, and an acid number, determined according to DIN 53240-1:2013-06, of 15 to 50 mg KOH/g.

Description

EXAMPLES

(1) Polymers:

(2) PC1: A commercially available polycarbonate based on bisphenol A having an MVR of 19 cm.sup.3/10 min (300° C./1.2 kg, ISO 1133-1:2011) and a Vicat softening temperature (VST/B 120; ISO 306:2013) of 145° C. (Makrolon® 2408 from Covestro Deutschland AG). M.sub.w, determined as described below, about 23 900 g/mol.

(3) PC2: A commercially available copolycarbonate based on bisphenol A and bisphenol TMC having an MVR of 18 cm.sup.3/10 min (330° C./2.16 kg, ISO 1133-1:2011) and a softening temperature (VST/B 120; ISO 306:2013) of 183° C. (Apec® 1895 from Covestro Deutschland AG). Mw, determined as described below, about 27 900 g/mol.

(4) Stabilizers:

(5) PMMI1: Polymethylmethacrylimide copolymer from Evonik (Pleximid® 8803) having a softening temperature (VST/B 50; ISO 306:2013) of 130° C. Acid number: 22.5 mg KOH/g, determined according to DIN 53240-1:2013-06. Proportion of MMI (methylmethacrylimide): 36.8% by weight, proportion of MMA (methyl methacrylate): 51.7% by weight, proportion of MMS (methylmethacrylic acid)+MMAH (methylmethacrylic anhydride): 11.5% by weight, in each case based on the total weight of the PMMI and determined by quantitative .sup.1H-NMR spectroscopy.

(6) PMMI2: Polymethylmethacrylimide copolymer from Evonik (Pleximid® TT50) having a softening temperature (VST/B 50; ISO 306:2013) of 150° C. Acid number: 22.5 mg KOH/g, determined according to DIN 53240-1:2013-06. Proportion of MMI: 83.1% by weight, proportion of MMA: 13.6% by weight, proportion of MMS+MMAH: 3.3% by weight, in each case based on the total weight of the PMMI and determined by quantitative .sup.1H-NMR spectroscopy.

(7) PMMI3: Polymethylmethacrylimide copolymer from Evonik (Pleximid® TT70) having a softening temperature (VST/B 50; ISO 306:2013) of 170° C. Acid number: 41.5 mg KOH/g, determined according to DIN 53240-1:2013-06. Proportion of MMI: 94.8% by weight, proportion of MMA: 4.6% by weight, proportion of MMS+MMAH: 0.6% by weight, in each case based on the total weight of the PMMI and determined by quantitative .sup.1H-NMR spectroscopy.

(8) Stab1: A maleic-anhydride-modified ethylene-propylene-1-octene terpolymer wax (ethene:propene:1-octene weight ratio 87:6:7) from Mitsui Chemical America, Inc. (Hiwax™ 1105A) having an average molecular weight (gel permeation chromatography in ortho-dichlorobenzene at 150° C. with polystyrene calibration) M.sub.w=6301 g/mol, M.sub.n=1159 g/mol and having an acid number of 52.6 mg KOH/g (test method JIS K0070). Maleic anhydride content: 4.4% by weight, based on the total weight of the terpolymer.

(9) Stab2: A maleic anhydride-modified polypropylene copolymer from Honeywell (AC907P) having an average molecular weight (gel permeation chromatography in ortho-dichlorobenzene at 150° C. with polystyrene calibration) M.sub.w=20 700 g/mol, M.sub.n=1460 g/mol and with an acid number of 78 mg KOH/g (ASTM D-1386).

(10) Fillers:

(11) F1: Titanium dioxide from Kronos having a D.sub.50=210 nm (scanning electron microscopy, ECD method; Kronos® 2230).

(12) F2: Quartz material from Quarzwerke GmbH (50226 Frechen, Germany) obtainable under the trade name Amosil FW600 (D.sub.50=4 μm, D.sub.98=13 μm, unsized). This is a fired silicon dioxide having a D.sub.10/D.sub.90 ratio of about 1.5/10 determined according to ISO 13320:2009 and a specific surface area of about 6 m.sup.2/g determined according to DIN-ISO 9277:2014-01.

(13) F3: aluminium oxide from Fluka having a pH of 7.2 measured at room temperature with a Mettler Toledo MP230 pH meter and measured according to ISO 10390:2005 in aqueous suspension.

(14) Production Parameters:

(15) Method A.sup.[1]:

(16) The extruder used was a DSM Micro-Extruder MIDI 2000 having a capacity of 15 cm.sup.3. The melt temperature in the extruder was 280° C., the speed was 150 rpm and the residence time (RT) was 5 minutes or 10 minutes. A DSM injection moulding machine was used for the injection moulding. The melt temperature during injection moulding was: 300° C., the mould temperature 80° C.

(17) Method B.sup.[1]:

(18) The extruder used was a KraussMaffei Berstorff ZE 25 AX 40D-UTX twin-screw extruder. The melt temperature in the extruder was 300° C., the speed was 100 rpm and the throughput was 10 kg/h. The torque was 15% to 40%. Filler addition was effected via the side extruder at housing 5 (of 9).

(19) Analytical Methods:

(20) M.sub.w: Gel permeation chromatography, calibrated against bisphenol A polycarbonate standards, using dichloromethane as eluent. Calibration with linear polycarbonates (formed from bisphenol A and phosgene) of known molar mass distribution from PSS Polymer Standards Service GmbH, Germany, calibration by method 2301-0257502-09D (2009, German language) from Currenta GmbH & Co. OHG, Leverkusen. The eluent is dichloromethane. Column combination of crosslinked styrene-divinylbenzene resins. Diameter of analytical columns: 7.5 mm; length: 300 mm. Particle sizes of column material: 3 μm to 20 μm. Concentration of solutions: 0.2% by weight. Flow rate: 1.0 ml/min, temperature of solutions: 30° C. Injection volume; 100 μl. Detection by means of UV detector.

(21) Yellowness Index (Y.I.) was measured according to ASTM E313-10. Transmission values (Ty) were determined according to ASTM-E-308 and reflectivity was measured according to ASTM E 1331. Both Y.I. and Ty and reflection Ry were evaluated according to D65, 10° (light type: D65/observer: 10°). Gloss was measured according to ASTM D 523 Hunter UltraScanPRO, diffuse/8° (reference: ceramic absolute values). The colour values (L*a*b) were measured according to DIN EN ISO 11664-4:2012-06. The samples had a geometry of 6.0 mm×3.5 mm×1.5 mm.

(22) The viscosity of the polymer melts was determined according to ISO 11443:2005 at a melt temperature of 300° C. and a shear rate of 1000 s.sup.−1.

(23) The Vicat softening temperature (VST/B/50) of the compositions was measured on test specimens according to ISO 306:2013.

(24) The tensile modulus and tensile strength of the compositions were measured on test specimens according to ISO 527-1:2012.

(25) The penetration force and penetration deformation of the compositions were measured on test specimens according to ISO 6603-2:2000.

(26) Results:

EXAMPLES

(27) TABLE-US-00001 TABLE 1 Filler-free polycarbonate.sup.[1] and effect of PMMI 1V 2V 3V 4V 5V 6V 7V RT % by wt. % by wt. % by wt. % by wt. % by wt. % by wt. % by wt. PC1 100 99.8 99.5 99 98 96 94 PMMI1 0.2 0.5 1 2 4 6 M.sub.w [g/mol] 5 min 23365 23408 23395 23409 23493 23554 23689 .sup.[1]Compositions produced by method A

(28) In unfilled polycarbonate, there is no significant degradation of the polymer chains. Therefore, no stabilizer is required. As is apparent from Table 1, the addition of PMMI to filler-free polycarbonate does not have any adverse effect on molecular weight. The average molecular weights are at a constant level within the bounds of measurement accuracy.

(29) TABLE-US-00002 TABLE 2 Filler-free polycarbonate.sup.[1] and effect of PMMI 8V 9V 10V % by wt. % by wt. % by wt. PC1 99 99 99 PMMI1 1 PMMI2 1 PMMI3 1 M.sub.w [g/mol] 23595 23687 23819 Viscosity [Pa .Math. s] 214 198 183 Vicat temperature [° C.] 146.8 146.7 147.1 Tensile modulus [MPa] 2261 2212 2241 Tensile strength [MPa] 69.3 71.6 70 Penetration, maximum force [N] 5238 5218 5178 Penetration, deformation [mm] 19.8 19.5 19.0 .sup.[1]Compositions produced by method B

(30) In unfilled polycarbonate the three employed PMMI types exhibit virtually identical characteristics. The addition of 1% by weight of PMMI copolymer has an only minimal effect on the Vicat temperature. However, the effect of the different softening temperatures of the various PMMI copolymer types is already noticeable at 1% by weight addition:

(31) TABLE-US-00003 TABLE 3 Titanium dioxide-containing polycarbonate compositions.sup.[1] and effect of PMMI co-polymer 11V 12 13 14 15 16 17 RT % by wt. % by wt. % by wt. % by wt. % by wt. % by wt. % by wt. PC1 80 79.8 79.5 79 78 76 74 F1 20 20 20 20 20 20 20 PMMI1 0.2 0.5 1 2 4 6 M.sub.w [g/mol] 5 min 21300 22300 22847 23008 23512 23490 23588 Y.I. 5 min 4.52 4.94 3.60 4.02 3.99 3.39 3.94 L* (D65, 10°) 5 min 98.0 97.6 98.5 98.3 98.2 98.6 98.5 Ry (D65, 10°) [%] 5 min 94.99 93.99 96.18 95.59 95.35 96.31 96.07 .sup.[1]Compositions produced by method B

(32) The additional 20% by weight of titanium dioxide results in a molecular weight degradation of the polycarbonate, which is significant compared to pure polycarbonate, to 21 300 g/mol. Even small amounts of PMMI copolymer of 0.2% by weight bring about a marked reduction in the molecular weight degradation. Addition of only 2% by weight of PMMI copolymer already results in attainment of a plateau range at which further PMMI addition no longer has an appreciable effect and the molecular weight of the polycarbonate remains only minimally below that of the pure polycarbonate. Even after a residence time of 5 minutes the molecular weight is approximately at the level of the unfilled polycarbonate.

(33) In terms of yellowing (Y.I.) no significant difference within the concentration range (0% to 6% by weight of PMMI copolymer) is apparent; if anything the trend appears to be one of minimal reduction in yellowing. Compared to the unstabilized composition (example 11V) the L-value is unchanged and the reflectivity Ry of titanium dioxide-filled polycarbonate is not affected by the addition of PMMI copolymer either.

(34) TABLE-US-00004 TABLE 4 Titanium dioxide-containing polycarbonate compositions.sup.[1] and effect of different PMMI types 18V 19 20 21 RT % by wt. % by wt. % by wt. % by wt. PC1 80 79 79 79 F1 20 20 20 20 PMMI1 1 PMMI2 1 PMMI3 1 M.sub.w [g/mol] 5 min 21300 23008 23024 22801 Y.I. (D65, 10°) 5 min 4.52 4.02 4.03 3.88 .sup.[1]Compositions produced by method A

(35) The employed PMMI copolymer types differ in their content of MMI, MMA, acid and anhydride. No relevant difference in the stabilization of titanium dioxide-filled polycarbonate compositions is detectable between the different PMMI copolymers. Each of the three PMMI copolymers brings about good stabilization. In terms of yellowing too, no significant difference is detectable. Compared to the non-additized polycarbonate composition (example 18V) the addition of PMMI copolymer brings about a slight reduction in the Y.I. value and thus an improvement in yellowing.

(36) TABLE-US-00005 TABLE 5 Comparison of different acid/maleic anhydride-functionalized copolymers as stabilizers.sup.[1] 22V 23V 24V 25 26V 27V RT % by wt. % by wt. % by wt. % by wt. % by wt. % by wt. PC1 99 99 99 79 79 79 F1 20 20 20 PMMI1 1 1 Stab1 1 1 Stab 2 1 1 M.sub.w [g/mol] 5 min 23409 23382 23104 23008 23662 23431 Y.I. (D65, 10°) 5 min 12.75 22.98 16.55 4.02 2.98 3.74 Ty (%) 5 min 80.9 61.8 48.3 — — — .sup.[1]Compositions produced by method A

(37) In combination with titanium dioxide as a filler, PMMI1, Stab 1 and Stab 2 bring about an approximately equally effective stabilization of the polycarbonate.

(38) In unfilled polycarbonate (Examples 22V to 24V), compared to polycarbonate comprising the stabilizers Stab1 and Stab 2, addition of PMMI copolymer results in a Y.I. value that is markedly reduced, i.e. the yellowing is lower. Compared to the PMMI copolymer Stab1 and Stab 2 bring about more severe clouding, detectable by the reduction in the transmission to 61%/48%.

(39) TABLE-US-00006 TABLE 6 Comparison of different filler/additive ratios.sup.[1] 28 29 30 31V 32 33 34 RT % by wt. % by wt. % by wt. % by wt. % by wt. % by wt. % by wt. PC1 89.5 89 88 80 79.8 79.5 79 F1 10 10 10 20 20 20 20 PMMI1 0.5 1 2 0 0.2 0.5 1 F1/PMMI1 20 10 5 0 100 40 20 M.sub.w [g/mol] 5 min 22973 22994 22973 21300 22300 22847 23008 35 36 37 38 39 40 RT % by wt. % by wt. % by wt. % by wt. % by wt. % by wt. PC1 78 76 74 68.5 67 66 F1/PMMI1 20 20 20 30 30 30 PMMI1 2 4 6 1.5 3 4 F1/PMMI1 10 5 3.3 20 10 7.5 M.sub.w [g/mol] 5 min 23512 23490 23588 22967 22855 22905 .sup.[1]Compositions produced by method A Titanium dioxide-filled PC has a maximum achievable stabilization limit at 10% to 30% by weight of filler. This is approximately between 23000-23500 g/mol. The molecular weight no longer changes significantly above about 0.5% by weight of PMMI copolymer.

(40) TABLE-US-00007 TABLE 7 Stabilization of titanium dioxide-filled (co)polycarbonate compositions.sup.[1] with various PMMI copolymer types and waxes. 41V 42 43 44 45 46V 47V 48V 49V % by % by % by % by % by % by % by % by % by wt. wt. wt. wt. wt. wt. wt. wt. wt. PC1 80 79.5 79 78 77 79 78 79 78 PC2 F1 20 20 20 20 20 20 20 20 20 PMMI1 0.5 1 2 3 PMMI2 PMMI3 Stab1 1 2 Stab2 1 2 F1/Stab. 0 40 20 10 6.7 20 10 20 10 Viscosity [Pa .Math. s] 147 225 231 209 250 202 182 173 149 Vicat temperature 144.3 146.7 146.7 146.4 146.4 144.3 143.1 145.6 144.9 [° C.] Tensile modulus 2694 2694 2717 2714 2764 2604 2465 2685 2697 [MPa] Tensile strength 57.6 60.7 60.8 61.6 61.8 52.9 52.1 53.4 53.8 [MPa] Elongation at 33.4 63.1 52.8 68.6 63.2 71.5 82.1 53.9 66.7 break [%] Penetration, 4128 4467 4527 4600 4653 4124 3865 4099 3965 maximum force [N] Penetration, 13.8 14.1 14.0 13.9 14.0 14.6 13.9 14.0 13.6 deformation [mm] M.sub.w [g/mol] 22164 23386 23503 23589 23560 23575 23580 23463 23399 50 51 52 53 54V 55 56 57 % by % by % by % by % by % by % by % by wt. wt. wt. wt. wt. wt. wt. wt. PC1 89 67 79 79 PC2 80 79 79 79 F1 10 30 20 20 20 20 20 20 PMMI1 1 3 1 PMMI2 1 1 PMMI3 1 1 Stab1 Stab2 F1/Stab. 10 10 20 20 0 20 20 20 Viscosity [Pa .Math. s] 229 242 256 230 202 301 301 269 Vicat temperature 146.5 146.0 146.9 146.6 179.1 180.1 179.9 179.8 [° C.] Tensile modulus 2470 3105 2676 2726 2779 2767 2782 2767 [MPa] Tensile strength 60.8 62.4 59.9 59.8 68.1 69.7 70 70 [MPa] Elongation at 99.9 12.4 23.8 28.7 9.6 13.8 11.2 14.5 break [%] Penetration, 4798 3972 4369 4275 3293 4267 3000 2734 maximum force [N] Penetration, 15.7 11.1 13.8 13.5 9.7 11.9 8.8 8.3 deformation [mm] M.sub.w [g/mol] 23607 23466 23500 23343 25398 27034 26468 26296 .sup.[1]Compositions produced by method B

(41) The PMMI copolymer types 2 and 3 result in a markedly poorer elongation at break, i.e. toughness, in bisphenol A-based polycarbonate than the PMMI copolymer I (cf. examples 52, 53 with 43) which is, however, nevertheless in a good range. For polycarbonate copolymer PC-2 as the base material, no appreciable difference in terms of elongation at break is detectable between the employed PMMI copolymer types (examples 55 to 57). However, even at 1% by weight of PMMI copolymer a marked effect on molecular weight stabilization is detectable and is likely to be even more pronounced for greater amounts of PMMI copolymer. Compared to a non-additized composition (Ex. 54V) the addition of only 1% by weight of PMMI1 brings about markedly improved impact characteristics and an increased elongation at break also for PC-2 (Ex. 55). For PC-2 all three PMMI copolymer types increase toughness while strength/stiffness remain unchanged (cf. Ex. 54 V with Ex. 55-57).

(42) Stabilization with Stab1 and Stab2 in identical amounts (1% or 2% by weight) as for PMMI copolymer 1 for comparison has a comparable effect on reducing molecular weight degradation. However, the compositions containing the polyolefin systems Stab1/Stab2 show a relevant reduction in the Vicat temperature. In addition, the mechanical properties are altogether poorer compared to a composition comprising PMMI copolymer; the tensile modulus and tensile strength are reduced. Addition of Stab1 und Stab2 further results in significantly poorer impact characteristics (measured by a achievable maximum force in penetration test) than for addition of PMMI1 (Ex. 46V-49V compared to Ex. 43, 44).

(43) TABLE-US-00008 TABLE 8 Fired silicon dioxide-containing polycarbonate compositions.sup.[1] and effect of PMMI copolymer 58V 59 60 61 62 63 64 % by wt % by wt % by wt % by wt % by wt. % by wt % by wt PC1 80 79.8 79.5 79 78 76 74 F2 20 20 20 20 20 20 20 PMMI1 0.2 0.5 1 2 4 6 RT M.sub.w [g/mol] 5 min 22299 not tested 23388 23556 23581 M.sub.w [g/mol] 10 min 21424 23582 23513 23523 .sup.[1]Compositions produced by method A

(44) Compared to other inorganic fillers the fired silicon dioxide used here has a better compatibility with polycarbonate as is apparent from the lower molecular weight degradation of only about 1000 g/mol without additional stabilizer. The slightly acidic character of the silicon dioxide has a less pronounced incompatibility with polycarbonate. However, here too a stabilizing effect can still be achieved by addition of PMMI copolymer, a plateau range being achieved no later than about 2% by weight. Higher concentrations of 4-6% result in no further improvement.

(45) Particularly at a higher residence time of 10 minutes this stabilization is still effective and the molecular weight is at the level of unfilled PC. While without PMMI copolymer the molecular weight is reduced by a further 1000 g/mol (example 58V) the molecular weights of the additized compounds (examples 62-64) remain unchanged.

(46) TABLE-US-00009 TABLE 9 Measurement of material properties on stabilized compounds.sup.[1] 65 66 67 68V 69 70 71 72 73 74V % by wt. PC1 89.5 89 88 80 79.8 79.5 79 78 77 79 F2 10 10 10 20 20 20 20 20 20 20 PMMI1 0.5 1 2 0.2 0.5 1 2 3 Stab1 1 Stab2 Ratio F2/Stab 20 10 5 0 100 40 20 10 6.7 20 Viscosity 198 262 244 213 297 306 304 309 297 197 [Pa .Math. s] Vicat temperature 147.4 147.2 147 146.7 148 148.1 148 148.1 147.4 145.4 [° C.] Tensile modulus 2619 2639 2696 3179 3138 3195 3159 3212 3198 3031 [MPa] Tensile 60.5 61 61.3 61.9 61.4 62.4 62.6 63.1 63.2 51.2 strength [MPa] Elongation at 83 95.2 84 11.4 16 17.1 20.5 18.8 27 23 break [%] Penetration, 4664 4723 4806 3429 3383 3420 3988 3842 3811 3671 maximum force [N] Penetration, 14.4 14.5 14.9 9.5 9.9 10.2 10.9 10.5 10.3 11.9 deformation [mm] M.sub.w [g/mol] 23652 23722 23807 22623 23376 23659 23825 23834 23808 23491 75V 76V 77V 78 79 80 81 82 % by wt. PC1 78 79 78 68.5 67 66 58 56 F2 20 20 20 30 30 30 40 40 PMMI1 1.5 3 4 2 4 Stab1 2 Stab2 1 2 Ratio F2/Stab 10 20 10 20 10 7.5 20 10 Viscosity —.sup.[2] 196 121 376 374 362 503 474 [Pa .Math. s] Vicat temperature 144.3 146.7 146.2 149.1 148.4 148.3 149.6 149.2 [° C.] Tensile modulus 2975 3151 3216 3825 3917 3902 4747 4802 [MPa] Tensile 45.9 49.2 45.6 65 65.4 65.8 68.1 69.1 strength [MPa] Elongation at 16 31.3 36.4 14.2 14.4 10.9 5 4.8 break [%] Penetration, 1535 3664 3382 852 666 780 533 457 maximum force [N] Penetration, 7.9 12.5 12.2 4.4 3.7 4 4.8 4.6 deformation [mm] M.sub.w [g/mol] 23683 23512 23597 23749 23763 23814 23746 23829 .sup.[1]Compositions produced by method B; .sup.[2]Sample too runny

(47) Upon addition of the wax Stab1 the tensile modulus is slightly reduced (examples 74V, 75V) compared to compositions to which PMMI copolymer has been added (examples 71, 72). Tensile strength remains approximately constant upon addition of PMMI copolymer or increases slightly (examples 69 to 73), while markedly decreasing upon addition of Stab or Stab2. While the filler per se initially has a reinforcing effect this is partially lost again as a result of Stab1 or Stab2 despite these having a stabilizing effect; Stab1 and Stab2 have a plasticizing effect. The Vicat temperature is also significantly reduced (Ex. 71, 72 with 74V-77V). The PMMI copolymer also brings about a slightly better stabilization compared to Stab1 and Stab2 (Ex. 71, 72 with 74V-77V). After an addition amount of about 1% by weight a plateau range is attained.

(48) The compositions containing 10% by weight of fired silicon dioxide and PMMI copolymer (examples 65 to 67) exhibit very high elongation at break values.

(49) TABLE-US-00010 TABLE 10 Fired silicon dioxide-containing polycarbonate compositions.sup.[1] and effect of different PMMI types 83 84 85 % by wt. PC1 79 79 79 F2 20 20 20 PMMI1  1 PMMI2  1 PMMI3  1 Viscosity [Pa .Math. s] 304  291  294  Vicat temperature [° C.] 148   148.3  148.2 Tensile modulus [MPa] 3159  3207  3202  Tensile strength [MPa]   62.6   62.7   62.4 Penetration, maximum 3988  4013  3690  force [N] Penetration, deformation   10.9 11   10.4 [mm] Mw (g/mol) 23 825    23 436    23 253    .sup.[1]Compositions produced by method B

(50) Examples 83 to 85 show that in silicon dioxide-containing compositions the PMMI copolymer having the lowest imide proportion (PMMI1) has the strongest stabilizing effect against molecular weight degradation. PMMI2 achieves the best mechanics (tensile, penetration) and the best Vicat temperature coupled with the best flowability, i.e. lowest viscosity.

(51) TABLE-US-00011 TABLE 11 Aluminium oxide-filled compositions.sup.[1] and effect of PMMI copolymer 86V 87 RT % by wt. % by wt. PC1 90 89 F3 10 10 PMMI1  1 M.sub.w 5 15 844    19 321    .sup.[1]Compositions produced by method A

(52) The degradation caused by 10% by weight of Al.sub.2O.sub.3 at a residence time of 5 min is already very pronounced but can be markedly reduced using only 1% PMMI copolymer.