Mineral-filled thermoplastic composition having good mechanical properties

Abstract

The invention relates to a composition for producing a thermoplastic moulding material, wherein the composition contains the following constituents: A) at least one polymer selected from the group consisting of aromatic polycarbonate, aromatic polyestercarbonate and polyester, B) at least one anhydride-functionalized ethylene-α-olefin copolymer or ethylene-α-olefin terpolymer having a weight-average molecular weight Mw of 50000 to 500000 g/mol determined by high-temperature gel permeation chromatography using ortho-dichlorobenzene as solvent against polystyrene standards, C) a talc-based mineral filler, and also to a process for producing the moulding material, to the moulding material itself, to the use of the composition or of the moulding material for producing moulded articles and to the moulded articles themselves.

Claims

1. A composition for producing a thermoplastic moulding material, wherein the composition consists of the following constituents: A) at least one polymer selected from the group consisting of aromatic polycarbonate, aromatic polyestercarbonate and polyester, B) at least one anhydride-functionalized ethylene-α-olefin copolymer or ethylene-a-olefin terpolymer having a weight-average molecular weight Mw of 50000 to 500000 g/mol determined by high-temperature gel permeation chromatography using ortho-dichlorobenzene as solvent against polystyrene standards, C) a talc-based mineral filler, and D) a polymer additive selected from the group consisting of flame retardants, anti-drip agents, flame retardant synergists, smoke inhibitors, lubricants, demoulding agents, nucleating agents, antistats, conductivity additives, stabilizers, flow promoters, compatibilizers, fillers and reinforcers distinct from component C, dyes and pigments.

2. The composition according to claim 1, wherein the component B consists of 2 to 40 mol % of α-olefin units and 60 to 98 mol % of ethylene units based on the sum of α-olefin and ethylene.

3. The composition according to claim 1, wherein the component B has a content of anhydride of 0.1% to 3.0% by weight.

4. The composition according to claim 1, wherein the component B is a maleic anhydride-functionalized copolymer of ethylene and 1-octene.

5. The composition according to claim 1, wherein the component B consists of 10 to 25 mol % of 1-octene units and 75 to 90 mol % of ethylene units based on the sum of 1-octene and ethylene.

6. The composition according to claim 1, wherein the component A consists solely of aromatic polycarbonate.

7. The composition according to claim 1, wherein talc is employed as component C.

8. The composition according to claim 1, consisting of 40% to 98.9% by weight of the component A, 0.1% to 10% by weight of the component B, 1% to 40% by weight of the component C, 0% to 20% by weight of polymer additives as component D.

9. The composition according to claim 1, wherein the component D comprises at least one stabilizer selected from the group of the phenolic antioxidants, phosphites and Brønsted acids.

10. A process for producing moulding materials, containing the steps (i), (ii) and optionally (iii), wherein in a first step (i) a composition according to claim 1 is heated by introduction of thermal and/or mechanical energy, at least the component A) is thus melted and all employed components are dispersed and/or dissolved in one another and in a further step (ii) the melt resulting from process step (i) is (ii) resolidified by cooling and (iii) optionally pelletized, wherein the process steps (ii) and (iii) may be performed in any desired sequence relative to one another.

11. The process according to claim 10, wherein the process is performed with a compounding unit and the component C is added separately from the other components.

12. The process according to claim 11, wherein the compounding unit used is a twin-screw extruder and the component C is added into a zone downstream of the melting zone for the other components via an ancillary intake.

13. A moulding material obtained by the process according to claim 10.

14. A method comprising utilizing the composition according to claim 1 for producing moulded articles.

15. A moulded article obtained from the composition according to claim 1.

Description

EXAMPLES

(1) Components Employed

(2) Component A:

(3) A1: Linear polycarbonate based on bisphenol A having a weight-average molecular weight M.sub.w of 28000 g/mol determined by gel permeation chromatography in methylene chloride with a polycarbonate standard.

(4) Component B:

(5) B1: Maleic anhydride (MAH)-functionalized ethylene-1-octene copolymer having an MAH content of 0.8% by weight and a ratio of ethylene to 1-octene of 87 mol % to 13 mol % and a weight-average molecular weight M.sub.w of 200 000 g/mol (Paraloid™ EXL 3808 D from Dow Chemical).

(6) B2: Maleic anhydride (MAH)-functionalized ethylene-1-octene copolymer having an MAH content of 0.4% by weight and a ratio of ethylene to 1-octene of 83 mol % to 17 mol % and a weight-average molecular weight M.sub.w of 322 000 g/mol (Paraloid™ EXL 3815 from Dow Chemical).

(7) B3 (comparison): Ethylene-propylene-octene-maleic anhydride copolymer having an ethylene:propylene:octene ratio in % by weight of 87:6:7 (corresponds to 94:4:2 in mol %), CAS No. 31069-12-2, having a molecular weight Mw of 5000 g/mol determined by GPC with a polystyrene standard and a maleic anhydride proportion of 4.4% by weight, HiWax™ 1105 A (from Mitsui Chemicals).

(8) B4 (comparison): Kane ACE™ M732, impact modifier having core-shell structure and a butadiene rubber core (from Kaneka).

(9) Component C:

(10) Talc, HTP Ultra™ from Imi Fabi having an MgO content of 31.0% by weight, an SiO.sub.2 content of 61.5% by weight and an Al.sub.2O.sub.3 content of 0.4% by weight, average particle size d.sub.50=0.65 μm.

(11) Component D:

(12) D1: Heat stabilizer, Irganox™ B900 (mixture of 80% Irgafos™ 168 (tris(2,4-di-tert-butylphenyl) phosphite) and 20% Irganox™ 1076 (2,6-di-tert-butyl-4-(octadecanoxycarbonylethyl)phenol); BASF (Ludwigshafen, Germany).

(13) D2: Demoulding agent pentaerythritol tetrastearate.

(14) D3: Citric acid, purity≥99.5% from Acros Organics (Geel, Belgium).

(15) Production and Testing of the Moulding Materials According to the Invention

(16) The mixing of the components was carried out in a Leistritz ZSE-27Maxx twin-screw extruder at a melt temperature of 260° C. In experiments 5, 6, V7 and V8 the talc was added into a zone downstream of the melting zone for the other components via an ancillary intake.

(17) The moulded articles were produced at a melt temperature of 300° C. and a mould temperature of 80° C. in an Arburg 270 E injection moulding machine.

(18) MVR is determined according to ISO 1133 (2012 version) at 300° C. using a loading of 1.2 kg and a melting time of 5 minutes.

(19) The Charpy impact strength was determined at 23° C. and −30° C. according to ISO 179/1eU on 10 test specimens having dimensions of 80 mm×10 mm×4 mm in each case.

(20) The breaking elongation and the nominal breaking elongation were determined at room temperature according to ISO 527 (1996 version).

(21) Used as a further measure of ductility in the practice-relevant impact/crash test was the behaviour in the multiaxial penetration test. The penetration test was performed at 23° C. based on ISO 6603-2 (2000 version; “based on” means that no visual check of the test specimens was performed) using test specimens having dimensions of 60 mm×60 mm×2 mm.

(22) TABLE-US-00001 TABLE 1 Compositions and properties thereof 1 2 V3 V4 5 6 V7 V8 Component (% by wt.) A1 74.40 74.40 74.40 74.40 74.40 74.40 74.40 74.40 B1 5.00 5.00 B2 5.00 5.00 B3 5.00 5.00 B4 5.00 5.00 C 20.00 20.00 20.00 20.00 20.00 20.00 20.00 20.00 D1 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 D2 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 D3 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 Talc addition Main intake (MI) or ancillary intake (AI) MI MI MI MI AI AI AI AI Properties Charpy impact strength Number fractured/unfractured (23° C.)  0/10  0/10  0/10 10/0  0/10  0/10  3/7 10/0 Average for fractured bars (23° C.) kJ/m.sup.2 n.f. n.f. n.f. 107 n.f. n.f.  187/n.f. 69 Number fractured/unfractured (−30° C.) 10/0 10/0 10/0  9/0 10/0 10/0 10/0 10/0 Average for fractured bars (−30° C.) kJ/m.sup.2 214 230 231 90 209 190 179 75 Penetration Maximum force (23° C.) N 4452 4329 1100 3694 4276 4250 1201 3788 Total energy (23° C.) J 36 34 7 22 30 30 4 19 Tensile test Breaking elongation % 14.5 3.1 2.8 3.0 88.3 86.7 15.6 6.7 Nominal breaking elongation % 8.3 3.3 3.1 3.5 60.3 58.5 8.7 5.0 MVR (1.2 kg - 5 min, 300° C.) cm3/[10 min] 6.5 7.6 14.7 6.5 6.7 8.9 15.5 8.2 n.f.: not fractured

(23) The data from table 1 show that the compositions 1, 2, 5 and 6 according to the invention containing the components B1 and B2 can be used to produce moulding materials having good melt flowability (MVR value not impaired compared to V4) and moulded articles having good toughness in impact tests, penetration tests and in tensile tests. When a graft polymer having a core-shell structure is employed (B4) instead of the inventive component B1/B2, impact strength and also maximum force and total energy in the penetration test are lower. When using the elastic component B3 the impact strength is similar to that obtained with B1 or B2 but toughness in the penetration test is markedly impaired.

(24) Also particularly advantageous when using the component B1 are the markedly improved breaking elongation and nominal breaking elongation.

(25) Furthermore, examples 5 and 6 show that addition of the talc-based mineral filler via an ancillary intake brings about a marked improvement in breaking elongation and nominal breaking elongation in the inventive compositions. While the comparative examples V7 and V8 also show an advantage from addition via an ancillary intake, the enhancements in breaking elongation and nominal breaking elongation are markedly less pronounced.