Polycarbonate composition comprising pearlescent pigment and/or interference pigment

Abstract

The invention relates to compositions based on aromatic polycarbonate comprising metal oxide-coated micas as effect pigment, which do not have any significant increase in molecular weight of the polycarbonate, as can be seen from the MVR, under thermal stress. This is achieved by the addition of small amounts of an anhydride-modified α-olefin polymer, optionally in combination with phosphorus-containing thermal stabilizer.

Claims

1. A composition comprising A) 50 wt % to 98.5 wt % of aromatic polycarbonate, having melt volume flow rate (MVR) of from 5 to 20 cm.sup.3/(10 min) determined according to ISO 1133:2012-03 at a testing temperature of 300° C. with a load of 1.2 kg, B) 0.8 wt % to ≤3.0 wt % of interference pigment and/or pearlescent pigment comprising a titanium dioxide-coated mica; C) 0.05 wt % to ≤3 wt % of anhydride-modified α-olefin polymer, wherein the olefinic portion of the anhydride-modified α-olefin polymer has an ethylene content of 65.0-96.0 wt %, a propylene content of 2.0-10.0 wt % and a 1-octene content of 2.0-25.0 wt % and D) 0.001 wt % to 0.500 wt % of one or more phosphorus-containing thermal stabilizers.

2. The composition according to claim 1, comprising A) 90.0 wt % to 97.5 wt % of aromatic polycarbonate, B) 1.0 to 2.5 wt % of interference pigment and/or pearlescent pigment comprising a titanium dioxide-coated mica, C) 0.02 wt % to ≤1 wt % of anhydride-modified α-olefin polymer.

3. The composition according to claim 1, comprising 1.2 to 2.0 wt % of interference pigment and/or pearlescent pigment comprising a titanium dioxide-coated mica.

4. The composition according to claim 1, wherein component D comprises one or more phosphites as thermal stabilizer.

5. The composition according to claim 1, wherein component D comprises i) phosphine, phosphite and phenolic antioxidant or ii) phosphine, phosphonite and phenolic antioxidant as phosphorus-containing thermal stabilizers.

6. The composition according to claim 1, wherein the thermal stabilizer present is bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite.

7. The composition according to claim 1, wherein the anhydride-modified α-olefin polymer has an average molecular weight M.sub.w, determined by means of gel permeation chromatography in ortho-dichlorobenzene at 150° C. with polystyrene calibration, of 1000 to 15 000 g/mol and an acid number of 45 to 170 mg KOH/g, determined according to DIN ISO 17025, by means of potentiometric titration.

8. The composition according to claim 1, wherein the composition has a melt volume flow rate (MVR) of 8 cm.sup.3/(10 min) or less, determined according to ISO 1133:2012-03 at a testing temperature of 300° C. with a load of 1.2 kg.

9. A moulding produced from a composition according to claim 1.

10. The composition according to claim 1, wherein the composition comprises A) 90.0 wt % to 97.5 wt % of aromatic polycarbonate, B) 1.2 wt % to 2.0 wt %, of pearlescent pigment and/or interference pigment from the group of the titanium dioxide-coated micas, C) 0.2 wt % to ≤1 wt % of anhydride-modified α-olefin polymer, wherein the olefinic portion of the anhydride-modified α-olefin polymer has an ethylene content of 65.0-96.0 wt %, a propylene content of 2.0-10.0 wt % and a 1-octene content of 2.0-25.0 wt %, D) 0.05 to 0.270 wt % of phosphorus-containing thermal stabilizer comprising i) phosphine, phosphite and phenolic antioxidant or ii) phosphine, phosphonite and phenolic antioxidant, E) up to 7% by weight of further additives selected from the group consisting of flame retardants, anti-dripping agents, thermal stabilizers other than component D), impact modifiers, fillers, antistats, colourants, pigments other than component B, carbon black, lubricants, demoulding agents, hydrolysis stabilizers, compatibilizers, UV absorbers and/or IR absorbers.

11. The composition according to claim 10, wherein the composition consists of component A), B), C), D) and E).

12. The composition according to claim 10, wherein further additives optionally present according to component E are solely colourants, demoulding agents, thermal stabilizers other than component D and/or pigments other than component B.

13. A composition comprising: A) 50 wt% to 98.5 wt% of aromatic polycarbonate, having melt volume flow rate (MVR) of from 5 to 20 cm.sup.3/(10 min) determined according to ISO 1133:2012-03 as a testing temperature of 300° C. with a load of 1.2 kg, B) 0.8 wt% to ≤ 3.0 wt% of interference pigment and/or pearlescent pigment comprising a titanium dioxide-coated mica; C) 0.05 wt% to ≤ 3 wt% of anhydride-modified olefin polymer, wherein the anhydride-modified olefin polymer has been modified with maleic anhydride and is based on polypropylene, and 0.001 wt to 0.500 wt% of one or mroe phosphorus-containing thermal stabilizers.

Description

EXAMPLES

(1) A: Makrolon® 3108 powder from Covestro Deutschland AG. Linear polycarbonate based on bisphenol A having a melt volume flow rate MVR of 6 cm.sup.3/(10 min) (as per ISO 1133:2012-03, at a testing temperature of 300° C. with a load of 1.2 kg). B-1: Pearlescent pigment. Anatase-coated mica Mearlin® Magnapearl® 3000 from BASF SE. B-2: Mearlin® Magnapearl® 1100 pearlescent pigment. Rutile-coated mica; manufacturer: BASF SE. B-3: Mearlin® Magnapearl® 2300 pearlescent pigment. Rutile-coated mica; manufacturer: BASF SE. B-4: Iriodin® 119 Way pearlescent pigment. Rutile-coated mica; manufacturer: Merck KGaA. B-5: Pyrisma® M30-58 Ambercup Orange. Pearlescent pigment TiO.sub.2— and Fe.sub.2O.sub.3-coated mica; manufacturer Merck. B-6: Iriodin® 119 Polar White. Rutile-coated mica; manufacturer: Merck KGaA. C-1: Maleic anhydride-modified ethylene-propylene-octene terpolymer (ethylene:propylene:1-octene 70:8:22), CAS No. 31069-12-2, with molecular weight (gel permeation chromatography in ortho-dichlorobenzene at 150° C. with polystyrene calibration) M.sub.w=4900 g/mol, M.sub.n=1159 g/mol, density 940 kg/m.sup.3, acid number 53 mg KOH/g, maleic anhydride content 4.5 wt %, based on the total weight of component C. The parameters stated (M.sub.n analogously to M.sub.w) were determined as described in the general part of the description. C-2: AC 907P. Maleic anhydride-modified polypropylene from Honeywell. D-1: ADK STAB® PEP-36, bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol diphosphite, available from Adeka Palmarole. D-2: Hostanox PEPQ. Stabilizer mixture, comprising tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenyl diphosphonite as the main component, available from Clariant. D-3: Irganox® 1076, n-octadecyl 3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, available from BASF SE. D-4: Irganox® B900, mixture of four parts Irgafos® 168 and one part Irganox® 1076. Irgafos® 168: tris(2,4-tert-butylphenyl) phosphite, available from BASF SE. D-5: triphenylphosphine, available from BASF SE. E1: pentaerythritol tetrastearate; Loxiol VPG 861 from Emery Oleochemicals. E-2: mixture of standard colourants and carbon black.

(2) The polycarbonate compositions described in the examples which follow in Tables I to 3 were produced by compounding in an Evolum EV32 extruder from Clextral with a throughput of 50 kg/h. The melt temperature was 300° C. Table 3 cites examples in which process parameters were varied.

(3) Melt volume flow rate (MVR) was determined according to ISO 1133:2012-03 (at a testing temperature of 300° C., mass 1.2 kg) using the Zwick 4106 instrument from Zwick Roell. The MVR relates to the value after heating for one minute plus holding at temperature for four minutes; the IMVR is the value after heating for one minute plus holding at temperature for 19 minutes.

(4) TABLE-US-00001 TABLE 1 Compositions and MVR 1V 2V 3V 4V 5V 6E 7E [wt %] [wt %] [wt %] [wt %] [wt %] [wt %] [wt %] A 97.48 97.38 97.28 97.38 97.28 97.28 97.38 B-1 1.94 1.94 1.94 1.94 1.94 1.94 1.94 C-1 0.4 0.4 D-1 0.08 0.16 0.16 D-2 0.08 0.16 0.08 D-3 0.02 0.04 0.02 0.04 0.024 0.02 D-4 D-5 0.05 0.05 0.05 0.05 0.05 0.05 0.05 E-1 0.4 0.4 0.4 0.4 0.4 E-2 0.13 0.13 0.13 0.13 0.13 0.13 0.13 MVR 12.74 11.57 9.72 12.64 12.09 7.92 7.65 [cm.sup.3/(10 mins)] 8E 9V 10V 11E 12E 13V 14V [wt %] [wt %] [wt %] [wt %] [wt %] [wt %] [wt %] A 97.28 97.38 97.28 97.38 97.28 97.48 97.48 B-1 1.94 1.94 1.94 1.94 1.94 1.94 1.94 C-1 0.4 0.4 0.4 D-1 D-2 0.16 D-3 0.04 D-4 0.1 0.2 0.1 0.2 D-5 0.05 0.05 0.05 0.05 0.05 0.05 0.05 E-1 0.4 0.4 0.4 0.4 E-2 0.13 0.13 0.13 0.13 0.13 0.13 0.13 MVR 7.93 12.57 14.21 7.57 7.51 11.78 17.83 [cm.sup.3/(10 mins)]

(5) TABLE-US-00002 TABLE 2 Compositions and properties 15V 16 17 18 19 20 [wt %] [wt %] [wt %] [wt %] [wt %] [wt %] A1 97.51 97.41 97.41 97.51 97.61 97.01 B-1 1.94 1.94 1.94 1.94 1.94 1.94 B-2 B-3 C-1 0.4 0.8 C-2 0.4 0.3 0.2 D-1 0.08 0.08 0.08 0.08 0.08 D-3 0.02 0.02 0.02 0.02 0.02 E-1 0.4 E-2 0.15 0.15 0.15 0.15 0.15 0.15 Properties MVR 12.5 7.0 6.7 6.9 7.0 7.1 [cm.sup.3/(10 min)] IMVR [cm.sup.3(10 min)] 17.5 7.8 7.1 6.7 7.1 7.0 Charpy notched impact (ISO 179/1eA) [kJ/m.sup.2] Number of tough/brittle/unbroken 0/9/0 5/5/0 10/0/0 Average of tough/brittle 0/15 48/27 53/0 (kJ/m.sup.2) 21 22 23V 24 25V 26 [wt %] [wt %] [wt %] [wt %] [wt %] [wt %] A1 98.35 95.95 97.51 97.41 97.51 97.41 B-1 1.0 3.0 B-2 1.94 1.94 B-3 1.94 1.94 C-1 0.4 0.8 0.4 0.4 C-2 D-1 0.08 0.08 0.08 0.08 D-3 0.02 0.02 0.02 0.02 E-1 0.4 0.4 E-2 0.15 0.15 0.15 0.15 0.15 0.15 Properties MVR 6.9 7.0 14.6 6.6 12.7 6.6 [cm.sup.3/(10 min)] IMVR [cm.sup.3(10 min)] 7.0 7.1 16.0 6.9 16.3 7.0 Charpy notched impact (ISO 179/1eA) [kJ/m.sup.2] Number of tough/brittle/unbroken 0/10/0 4/6/0 Average of tough/brittle 0/14 36/24 (kJ/m.sup.2) 27 V 28 29 V 30 31 V 32 [wt %] [wt %] [wt %] [wt %] [wt %] [wt %] A1 97.51 97.41 97.51 97.41 97.51 97.41 B-4 1.94 1.94 B-5 1.94 1.94 B-6 1.94 1.94 C-1 0.4 0.4 0.4 D-1 0.08 0.08 0.08 D-3 0.02 0.02 0.02 E-1 0.4 0.4 0.4 E-2 0.15 0.15 0.15 0.15 0.15 0.15 Properties MVR [cm.sup.3/(10 min)] 10.0 6.6 10.7 7.1 20.2 7.0 IMVR [cm.sup.3/(10 min)] 11.6 6.8 14.7 7.5 20.4 7.2 Charpy notched impact (ISO 179/1eA) Number of tough/brittle/unbroken 0/10/0 6/3/0 0/10/0 0/9/0 0/10/0 9/0/0 Average of tough/brittle 0/15 55/25 0/16 0/24 0/14 43/0 [kJ/m.sup.2] It is apparent from the comparative tests (15V, 23V, 25V) without component C, compared to the analogous inventive tests with component C (Examples 16-22, 24, 26), that the addition of anhydride-modified α-olefin polymer leads to a significant reduction in the pigment-induced degradation of the polycarbonate. Significant stabilization of the polycarbonate by anhydride-modified α-olefin polymer also occurs in the case of micas coated by different metal oxide than titanium dioxide, here with titanium dioxide/iron oxide-coated mica (Example 30 compared to 29V), but the stabilizing effect here seems to be slightly worsened compared to those compositions comprising titanium dioxide-coated micas as pigment.

(6) TABLE-US-00003 TABLE 3 Dependence on the process parameters. 33V 34V 35V 36V 37 38 39 40 [wt %] [wt %] [wt %] [wt %] [wt %] [wt %] [wt %] [wt %] A1 97.51 97.51 97.51 97.51 97.41 97.41 97.41 97.41 B-1 1.94 1.94 1.94 1.94 1.94 1.94 1.94 1.94 C-1 0.4 0.4 0.4 0.4 D-1 0.08 0.08 0.08 0.08 D-3 0.02 0.02 0.02 0.02 E-1 0.4 0.4 0.4 0.4 E-2 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 Machine parameters Temperature (° C.) 280 280 300 300 280 280 300 300 Speed (rpm) 300 600 300 600 300 600 300 600 Properties MVR 17.2 26.6 16.8 25.5 6.5 6.7 6.5 6.6 [cm.sup.3/(10 min)] IMVR 19.7 28.3 19.1 27.4 7.1 7.2 6.7 7.2 [cm.sup.3/(10 min)] Charpy notched impact (ISO 179/1eA) Number of tough/brittle/unbroken 0/10/0 0/10/0 0/10/0 0/9/0 10/0/0 9/0/0 9/0/0 10/0/0 Average of tough/brittle 0/13 0/10 0/12 0/11 81/0 82/0 79/0 81/0 [kJ/m.sup.2] The results in Table 3 show that the effect of stabilization also occurs in the case of “harder” process conditions. Neither an increase in temperature by 20° C. nor twice as high a speed has any adverse effect on flowability in the case of stabilization; significant polymer degradation can thus be avoided in all the cases examined (tests 37 to 40). Without component C, however, (experiments 33V to 36V), there is significant polymer degradation, especially at elevated speeds (experiments 34V, 36V), as apparent from the higher MVR values and the poorer mechanical properties.