AU741719B2

AU741719B2 - ABS moulding compositions produced in an emulsion-free manner and with a very high notched bar impact strength

Info

Publication number: AU741719B2
Application number: AU60611/98A
Authority: AU
Inventors: Herbert Eichenauer; Peter Kruger; Edgar Leitz; Gisbert Michels; Ralph Ostarek; Richard Weider
Original assignee: Bayer AG
Current assignee: Bayer AG
Priority date: 1997-04-15
Filing date: 1998-04-01
Publication date: 2001-12-06
Anticipated expiration: 2018-04-01
Also published as: AR012416A1; AU6061198A; DE19715595A1; EP0872520A1; DE59807924D1; BR9801051A; JPH10292087A; CN1197816A; CN1137205C; ES2195214T3; CA2234542A1; EP0872520B1

Description

Our Ref: 679442 P/00/011 Regulation 3:2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT r Applicant(s): Bayer Aktiengesellschaft D-51368 Leverkusen

GERMANY

Address for Service: Invention Title: DAVIES COLLISON CAVE Patent Trade Mark Attorneys Level 10, 10 Barrack Street SYDNEY NSW 2000 ABS moulding compositions produced in an emulsion-free manner and with a very high notched bar impact strength The following statement is a full description of this invention, including the best method of performing it known to me:- 5020 Le A 32 296 -foreign countries KM/by/S-W6 ABS moulding compositions produced in an emulsion-free manner and with a very high notched bar impact strength ABS moulding compositions have already been used for many years in large amounts as thermoplastic resins for the production of mouldings of all types. The property spectrum of these resins ranges from relatively brittle to very tough.

One particular area of application for ABS moulding compositions is the production of mouldings on which severe demands are made as regards toughness on impact, particularly at low temperatures also, wherein the other properties, such as the modulus of elasticity, surface hardness and dimensional stability when hot should not be adversely affected.

Hitherto, it was only possible to approach property combinations such as these by using special graft rubbers produced by emulsion polymerisation, wherein high toughness values could only be obtained, however, at the cost of reduced values of the modulus of elasticity (due to increasing the total rubber content of the moulding compositions).

Other disadvantages of ABS polymers produced by emulsion polymerisation include the large amount of waste water which is formed during production or work-up, and the inherent yellowish colour imparted to products produced in this manner in their noncoloured state, due to their content of polymerisation processing materials (e.g.

emulsifiers).

The object was therefore to provide graft polymer moulding compositions of the ABS type (hereinafter abbreviated to ABS moulding compositions) having very high toughness values, wherein the production thereof should not be effected by emulsion polymerisation.

As the solution according to the invention which achieves this object, it has been found that ABS moulding compositions with the required properties can be obtained by a combination of particular finely divided ABS polymers having a high rubber content, which are specially Le A 32 296 -2produced by solution polymerisation, with special, coarse particulate, bulk, solution or suspension ABS polymers.

Combinations of ABS polymers with different particle sizes which are produced by bulk or solution polymerisation are known.

Thus, amongst other features, EP-A 412 801 describes the direct production of bimodal bulk ABS polymers by the polymerisation of rubber/monomer solutions in two reactors, whereupon particle sizes of 0.05 to 1.5 pm and 0.7 to 10 gm result; in practice, the rubber content of these ABS polymer resins is 7.4 by weight. Thus high-toughness ABS products cannot be produced by this means.

EP-A 507 117 describes ABS moulding compositions with a bimodal rubber particle size distribution (100-500 nm and 600-10,000 nm).

The rubber contents of the ABS polymer resins used are 17 by weight, and even at a maximum amount of 30 by weight which can be used in the moulding composition, high-toughness ABS moulding compositions cannot be obtained.

ooo 20 Bimodal moulding compositions of the ABS type are also described in US-PS 5 286 792, wherein the bimodality is obtained in one process step. The components with large or small rubber particle sizes can no longer be mixed in a targeted manner by this means; moreover bimodality is only made possible by the additional use of a comonomer which results in possible disadvantages reduced dimensional stability when hot).

The present invention relates to graft polymer moulding compositions of the ABS type, containing A) 30 to 80 parts by weight, preferably 35 to 75 parts by weight, and most preferably 40 to 70 parts by weight, of at least one graft polymer which is produced by solution polymerisation and which has a rubber content of 20 to Le A 32 296 -3by weight, preferably 22.5 to 45 by weight, and most preferably 25 to by weight, and an average particle diameter of the rubber phase of 80 to 600 nm, preferably 150 to 400 nm, and most preferably 200 to 350 nm, B) 5 to 50 parts by weight, preferably 7.5 to 45 parts by weight, and most preferably to 40 parts by weight, of at least one ABS polymer produced by bulk, solution or suspension polymerisation, which has a rubber content of 3 to 18 by weight, preferably 5 to 16.5 by weight, and most preferably 7.5 to 15 by weight, and an average particle diameter of the rubber phase of 700 to 15,000 nm, preferably of 800 to 10,000 nm, and most preferably of 1000 to 5000 nm and

C

C) 5 to 70 parts by weight, preferably 7.5 to 65 parts by weight, and most preferably 15 10 to 60 parts by weight, of at least one rubber-free thermoplastic resin synthesised from vinyl monomer units and produced by bulk, solution or suspension .*.polymerisation.

The production of ABS polymers B) is known. Thus these polymers can be produced by bulk or solution polymerisation methods or by suspension polymerisation (see DE-OS 3 100 785, US-PS 4 012 462, US-PS 4 362 850, EP-OS 67 356, for example).

The graft polymer corresponding to component A) is preferably polymerised by a radical mechanism from a monomer mixture comprising D) 90 to 20 parts by weight of an aromatic monoalkenyl compound, E) 10 to 50 parts by weight of an ethylenically unsaturated nitrile, F) 0 to 30 parts by weight of further copolymerisable compounds, in the presence of -4to 50 parts by weight per 100 parts by weight of monomer of a soluble, gel-free butadiene polymer or butadiene/styrene copolymer, and in the presence of to 200 parts by weight of a solvent per 100 parts by weight of monomers E) and F), wherein the solvent is an aliphatic (Ci-Cs) or cycloaliphatic (C 5

-C

6 alcohol, ketone, ether, ester or nitrile (Al) or a mixture of (Al) with an aliphatic (C 4

-C

1 0 cycloaliphatic or aromatic hydrocarbon (A2) in a ratio by weight of A1:A2 from 100:0 to 30:70, and the polymerisation is conducted as far as a polymer content in the total mixture of 30 to 70% by weight, with thorough mixing and optionally with the subsequent metered addition of regulators and initiator, so that the isolated thermoplastic moulding composition contains 20 to 50% by weight of butadiene o.. polymer.

The total rubber content of the moulding compositions according to the invention is preferably 5 to 30 by weight, more preferably 7.5 to 25 by weight, and most preferably 10 to 20 by weight.

Moreover, the proportion of rubber incorporated via ABS polymer A) is preferably to 95 by weight, more preferably 55 to 92.5 by weight, and most preferably 60 to 90 by weight (with respect to the total amount of rubber in the moulding composition in each case).

ABS polymers A) are produced by solution polymerisation using at least one solvent selected from an aliphatic or cycloaliphatic Ci-C 8 alcohol, ketone, ether, ester, nitrile, or a mixture of at least one of said solvents with an aliphatic or cycloaliphatic C 4

-C

1 0 hydrocarbon and/or aromatic hydrocarbon under special conditions of compatibility.

The polymer content of the total mixture here is preferably 30 to 60 by weight, particularly 35 to 50 by weight, the total content of solvent is 25 to 60 by weight, and the balance is unreacted monomers.

Le A 32 296 During the preferred production of component when using solvents or solvent mixtures from group (Al) and optionally from group (A2) in the given ratios by weight of 1:0 to 3:7, it is possible to pass rapidly through a phase inversion whilst achieving satisfactory conversions, despite higher rubber contents, so that a finely dispersed phase of graft rubber is formed.

The production of component A) can be carried out batch-wise, semi-continuously or continuously. In the continuous embodiment, the solution of monomers and rubber in solvents can advantageously be polymerised in a continuously fed, thoroughly mixed, stirred tank reactor, with a steady-state conversion of monomer in the first stage after phase inversion of more than 10 by weight with respect to the sum of monomers, and i radical-initiated polymerisation can be continued in at least one further stage as far as a monomer conversion, with respect to the sum of monomers, of 30 to 70 by weight, with thorough mixing in one or more further continuously operated stirred vessels in cascade, or in a thoroughly mixed graft flow reactor and/or in a combination of both types of reactor. Residual monomers and solvents can be removed by conventional techniques in heat-exchange evaporators, flash evaporators, long-tube .evaporators, thin film or thin layer evaporators, screw-type evaporators) and recycled to the process. It may also be advantageous to conduct continuous polymerisation in three stages, wherein the first stage is operated at a steady-state monomer conversion of less than 10 by weight before phase inversion and the further stages are operated with the conversions described above.

Batch-wise and semi-continuous polymerisation can be conducted in one or more filled or partly filled thoroughly mixed stirred vessels connected in series, with the rubber monomers and the solvent being placed in the vessel and with polymerisation being effected as far as the given monomer conversion of 30 to 70 by weight.

To achieve better mixing throughout and better comminution of the rubber fed in, the polymer syrup can be pumped in circulation, both for the continuous and batch-wise modes of operation, via elements which impart a thorough mixing and shearing effect.

"Loop operations" such as these are state of the art, and may be helpful in order to

I

Le A 32 296 -6adjust the particle size of the rubber. However, it is more advantageous to provide an arrangement of shearing elements between two separate reactors in order to prevent back-mixing, which results in a broadening of the particle size distribution.

The average residence time is 1 to 10 seconds. Polymerisation is advantageously conducted at 60 to 120°C, preferably at the boiling point of the solvent/polymer mixture.

Polymerisation is advantageously conducted at normal pressure, although polymerisation under a slight overpressure up to 6 bar is also possible.

The viscosities of the stirred or transported media are within a range with a maximum of 150 Pa.s.

The graft polymer can be isolated in the known manner by precipitation in solvents, by stripping with water and/or steam, or by evaporative concentration to form a polymer melt, e.g. in flash evaporators, long-tube evaporators, spiral tube evaporators, thin film evaporators, certain thin layer evaporators, falling film evaporators or screw-type evaporators.

Solvents and residual monomers can also be removed in stirred multi-phase evaporators 20 comprising kneading and stripping devices. The use of gas developing and entrainment agents, e.g. steam, is possible in conjunction; however, a very low residual monomer content can also be obtained by simple evaporative concentration methods without the use of entraining agents such as these, despite the high amounts of solvent.

Solvents of group (Al) are alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, tert.-butanol, amyl alcohol, isoamyl alcohol, isooctanol and cyclohexanol; ketones such as acetone, methyl ethyl ketone; methyl isopropyl ketone, cyclopentanone and cyclohexanone; ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl, -diethyl, -dipropyl and -diisopropyl esters; esters such as ethyl acetate, propyl acetate, butyl acetate etc., and nitriles such as acetonitrile, propionitrile or butyronitrile. Methyl ethyl ketone and acetone are preferred.

Le A 32 296 -7- Solvents of group (A2) are aliphatic hydrocarbons such as butane, pentane, hexane, heptane, octane or iso-derivatives thereof, cycloaliphatic hydrocarbons such as cyclopentane, cyclohexane, alkyl-cyclopentane and alkyl-cyclohexane, and aromatic hydrocarbons such as benzene, toluene, xylenes and ethylbenzene. Toluene and ethylbenzene are preferred.

Mixtures of acetone and ethylbenzene and of acetone and toluene are particularly preferred.

It is also possible to employ only solvents of group Methyl ethyl ketone is then preferred.

Customary molecular weight regulators can be used for adjusting the molecular weight, such as mercaptans and olefines, e.g. tert.-dodecylmercaptan, ndodecylmercaptan, cyclohexene, terpinols, dimeric ca-methylstyrene, etc., in amounts of 0.05 to 1.0 by weight with respect to the copolymerising monomers.

Suitable initiators for the radical-induced polymerisation are graft-active peroxides which decompose to form radicals, such as peroxycarbonates, peroxydicarbonates, diacyl peroxides, perketals or dialkyl peroxides, and/or azo compounds or mixtures thereof Examples include azodiisobutyric acid dinitrile, azoisobutyric acid alkyl esters, and tert.-butyl perpivalate, peroctoate, perbenzoate and perneodecanoate. These initiators are used in amounts of 0.01 to 1 by weight with respect to monomers 1. to 3.

Customary additives can be added during polymerisation or before work-up, such as the colorants, anti-oxidants, parting agents or stabilisers known to one skilled in the art.

Suitable rubbers for the production of component A) are preferably soluble, gel-free butadiene polymers, such as polybutadienes for example, as well as styrene-butadiene copolymers in random and/or block form with a high 1,2-vinyl fraction of 2 to 40 Le A 32 296 -8preferably 8 to 25 with respect to the double bonds, and with molecular weights of 50,000 to 500,000, including branched and star-shaped polymers with gel contents <1000 ppm.

The aromatic monoalkenyl compounds 1. are preferably styrene, ac-methylstyrene, alkylstyrenes with substituted nuclei, and chlorostyrenes with substituted nuclei The ethylenically unsaturated nitriles are preferably acrylonitrile or meth-acrylonitrile.

Examples of copolymerisable compounds include acrylic esters such as methyl (meth)acrylate, ethyl (meth)acrylate, tert.-butyl (meth)acrylate, esters of fumaric or itaconic acids, maleic derivatives such as maleic anhydride, maleic acid esters, N- -substituted maleinimides such as, advantageously, N-cyclohexyl- or N-phenylmaleinimide or N-alkyl-phenyl-maleinimide, and also acrylic acid, methacrylic acid, 15 fumaric acid, itaconic acid or amides thereof.

ABS polymers A) which are suitable according to the invention have a rubber content of 20 to 50 by weight, preferably 22.5 to 45 by weight, and most preferably 25 to by weight, and their average particle diameters are 80 to 600 nm, preferably 150 to 400 nm, and most preferably 250 to 350 nm.

In addition, ABS polymers A) preferably have a degree of grafting of 0.2 to 1 (see M.

Hoffmann, H. Kr6mer, R. Kuhn in "Polymeranalytik Georg Thieme Verlag Stuttgart 1977) and a gel content of 30 to 50 by weight (measured in methyl ethyl ketone).

The production of ABS polymers B) is known. These polymers can thus be produced by bulk or solution polymerisation methods or by suspension polymerisation (see DE- OS 3 100 785, US-PS 4 012 462, US-PS 4 362 850, EP-A-67 536, for example).

ABS polymers B) which are suitable according to the invention have a rubber content of 3 to 18 by weight, preferably 5 to 16.5 by weight, and most preferably 7.5 to Le A 32 296 -9by weight, and their average particle diameters are 700 to 15,000 nm, preferably 800 to 10,000 nm, and most preferably 1000 to 5000 nm.

Substances which are suitable according to the invention as rubber-free thermoplastic resins C) based on vinyl monomers and which are preferably used are homo-, co- or terpolymers which are produced by the polymerisation of styrene, a-methylstyrene, acrylonitrile, maleic anhydride, N-phenylmaleinimide or methyl methacrylate. Examples of polymers of this type include styrene/acrylonitrile copolymers, styrene/acrylonitrile/methyl methacrylate terpolymers, styrene/methyl methacrylate copolymers, acrylonitrile/methyl methacrylate copolymers, a-methylstyrene/acrylonitrile copolymers, styrene/a-methylstyrene/acrylonitrile terpolymers, amethylstyrene/methyl methacrylate/acrylonitrile terpolymers, styrene/a-methyl- :styrene/methyl methacrylate terpolymers, styrene/maleic anhydride copolymers, styrene/methyl methacrylate/maleic anhydride terpolymers, styrene/acrylonitrile/Nphenylmaleinimide terpolymers, styrene/N-phenylmaleinimide copolymers, and polymethyl methacrylate.

The preferred thermoplastic resins C) are styrene/acrylonitrile copolymers, amethylstyrene/acrylonitrile copolymers, styrene/N-phenylmaleinimide copolymers and styrene/acrylonitrile/N-phenylmaleinimide terpolymers.

Polymers of this type are known, and can be produced by radical-induced polymerisation, particularly by bulk, solution or suspension polymerisation. They preferably have average molecular weights M, of 20,000 to 200,000 or limiting viscosities [ii] of 20 to 110 ml/g (measured in dimethylformamide at 25 0

C).

The ABS moulding compositions according to the invention can be obtained by mixing their constituents A, B and C with each other at elevated temperature, particularly at T 100C to 280 0 C, e.g. in kneaders, in cylinder mills or in screw-type machines.

P:\WPDOCS Hj Specs\679442pgs.do~-23/0/01 Additives which are necessary or advisable can be added to the ABS moulding compositions according to the invention, during their production, work-up, further processing and final moulding. Examples include anti-oxidants, UV stabilisers, peroxide destroyers, parting agents, anti-static agents, demoulding agents, flame retardants, pigments, fillers or reinforcing agents (glass fibres, carbon fibres, etc.), and colorants.

The final moulding operation can be effected in commercially available processing units, .i and comprises injection moulding processing, sheet extrusion, optionally with subsequent hot forming, cold forming, extrusion of tubes and sections, and calender processing.

1 Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

Le A 32 296 11 Examples In the following examples, the parts quoted are always parts by weight and the percentages quoted are always percentages by weight, unless stated otherwise.

Polymer components ABS polymer Al A solution of 72 parts by weight of a rubber (poly-cis-butadiene-co-block-styrene, 11 by weight styrene, solution viscosity 27.5 mPa.s, 5 solution in styrene) in 257 parts by weight styrene, 120 parts by weight acrylonitrile and 229 parts by weight 2-butanone was placed in a 100 1 reactor fitted with an anchor agitator at 400 to 50 0 C, together with 0.95 parts by weight tert.-dodecylmercaptan, 0.15 parts by weight 2,5-di-tert.-butylphenol and 15 7.6 parts by weight paraffin oil. After heating to 75 oC, a solution of 0.57 parts by weight tert.-butyl perpivalate (60 in a hydrocarbon mixture) and 0.16 parts by weight tert.-butyl .peroctoate in 18 parts by weight 2-butanone was added, and stirring was continued for about 45 minutes until the end of the phase inversion (identifiable by the decrease in torque). The batch was then polymerised to the final conversion, with the addition of 0.19 :O 20 parts by weight tert.-dodecylmercaptan (dissolved in 37 parts by weight 2-butanone), and whilst increasing the temperature (1.5 hours at 84 0 C, 1 hour at 87 0 C, 4.5 hours at 90 0

C),

after which 2 parts by weight p- 2 ,5-di-tert.-butylphenol-propionic acid octyl ester (Irganox 1076, Ciba-Geigy) (dissolved in 11 parts by weight 2-butanone) were added as a stabiliser.

The solids content of the polymerisation syrup after completion of the reaction was 39 by weight. The solution was then concentrated in a ZSK laboratory screw-type evaporation concentrator, up to a final temperature of250 0 C, and was granulated. The granular material contained 25 by weight of rubber, the gel content (measured in acetone) was 33 by weight, and the average particle size of the rubber phase (weight average value) was about 250 nm.

Le A 32 296 12- ABS polymer B 1 An ABS polymer produced by suspension polymerisation, with a rubber content (polybutadiene) of 15 by weight, an acrylonitrile content of the styrene/acrylonitrile copolymer phase of 26 by weight, a gel content (measured in acetone) of 26.5 by weight, and an average particle size of the rubber phase (weight average value) of about 1500 nm.

ABS polymer B 2 An ABS polymer produced by suspension polymerisation, with a rubber content (polybutadiene) of 13.5 by weight, an acrylonitrile content of the styrene/acrylonitrile copolymer phase of 26 by weight, a gel content (measured in acetone) of 27 by weight, and an average particle size of the rubber phase (weight average value) of about 15 8000 nm.

ABS polymer V (comparison material) An ABS polymer produced by emulsion polymerisation, with a rubber content e. .20 (polybutadiene) of 55 by weight, an acrylonitrile content of the styrene/acrylonitrile copolymer phase of 27 by weight, a gel content (measured in acetone) of 89 by weight, and an average particle size of the rubber phase (weight average value) of about 450 nm.

Thermoplastic resin C 1 A styrene/acrylonitrile random copolymer produced by solution polymerisation (styrene/acrylonitrile ratio by weight 72:28) with an average molecular weight Mw of about 85,000 and Mw/M -1 2.

Le A 32 296 -13- Moulding compositions The polymer components described above were mixed in the proportions given in Table 1, in an internal kneader, together with 1 part by weight pentaerythritol tetrastearate, and after granulation were processed by injection moulding to form test bars and to form a flat sheet (for the assessment of the surface).

The following data were determined: the notched bar impact toughness at room temperature (akRT) and at -40 0 C (a&k according to ISO 180 1/A (units: k/m 2 "the indentation hardness HL according to DIN 53 456 (units: N/mm 2 the MVI flow properties according to DIN 53 753 U (units: cm 3 /10 min), and the gloss properties according to DIN 67530 at an angle of reflection of 600 (reflectometer value).

20 It can be seen from the examples that the moulding compositions according to the invention result in excellent toughness values, both at room temperature and at low temperature, with i good values of hardness and flowability being obtained at the same time. The surface gloss could be varied over a wide range, and was centred on the production of mouldings with matt surfaces.

Le A32 296 14 Table 1: Compositions of moulding compositions Data in parts by weight Example Al BI B2 A 9 9* 1 2 3 4 5 6 (comparison) 7 (comparison) 8 (comparison) 43 38.5 33.5 43 38.5 48 Cl. Total rubber content in the moulding composition by weight) 49 12 45.5 12 42.5 12 48 12 43 12 52 12 20 12 9 18.5 (comparison) 11 12 13 14 (comparison) 57.5 50.5 65 72 23 18.5 13.5 21 28 32.5 67.5 (comparison) Le A32 296 15 Table 2: Test data on moulding compositions Example 1 2 3 4 6 (comparison) 7 (comparison) (kJ/m') 21.3 27.4 27.4 21.9 22.4 6.7 ak -40C (ki/in 2 8.9 9.0 9.0 7.8 7.5 6.4 111 108 107 106 98 110 Mxq (cm 3 /1 0 min) 12.3 11.7 14.6 13.5 13.6 8.5 Gloss (reflectometer value) 59 72 76 58 92 t. S.

.5 5 *55* 5*55

S

**5*S

S.

5 5 *5 5*5* (S S S *5 12.0 10.0 14.3 10.4 31.0 (comparison) 9 (comparison) 10 11 12 13 14 (comparison) 7.1 6.1 117 143:. 53.4 52.1 48.1 24.9 16.1 30.1I 28.2 26.4 30.9 14.2 24.1 (comparison)

Claims

1. Graft polymer moulding compositions of the ABS type, containing A) 30 to 80 parts by weight of at least one graft polymer which is produced by solution polymerisation and which has a rubber content of 20 to by weight and an average particle diameter of the rubber phase of to 600 nm, B) 5 to 50 parts by weight of at least one ABS polymer produced by bulk, solution or suspension polymerisation, which has a rubber content of 3 to 18 by weight and an average particle diameter of the rubber phase of 700 to 15,000 nm, v* and C) 5 to 70 parts by weight of at least one rubber-free thermoplastic resin synthesised from vinyl monomer units and produced by bulk, solution or suspension polymerisation.

2. ABS moulding compositions according to claim 1, containing A) 35 to 75 parts by weight of at least one ABS polymer which is produced by solution polymerisation and which has a rubber content of 22.5 to by weight and an average particle diameter of the rubber phase of 150 to 400 nm, B) 7.5 to 45 parts by weight of at least one ABS polymer produced by bulk, solution or suspension polymerisation, which has a rubber content of 5 to

16.5 by weight and an average particle diameter of the rubber phase of 800 to 10,000 nm, Le A 32 296

17- and C) 7.5 to 65 parts by weight of at least one rubber-free thermoplastic resin synthesised from vinyl monomer units and produced by bulk, solution or suspension polymerisation. 3. ABS moulding compositions according to claim 1, containing A) 40 to 70 parts by weight of at least one ABS polymer which is produced by solution polymerisation and which has a rubber content of 25 to by weight and an average particle diameter of the rubber phase of 200 to 350 nm, B) 10 to 40 parts by weight of at least one ABS polymer produced by bulk, solution or suspension polymerisation, which has a rubber content of 7.5 to by weight and an average particle diameter of the rubber phase of 1000 to 5000 nm, and C) 10 to 60 parts by weight of at least one rubber-free thermoplastic resin synthesised from vinyl monomer units and produced by bulk, solution or suspension polymerisation. 4. ABS moulding compositions according to claims 1 to 3, wherein the graft polymer corresponding to component A) is polymerised by a radical mechanism from a monomer mixture comprising D) 90 to 20 parts by weight of an aromatic monoalkenyl compound, E) 10 to 50 parts by weight of an ethylenically unsaturated nitrile,

18- F) 0 to 30 parts by weight of further copolymerisable compounds, in the presence of to 50 parts by weight per 100 parts by weight of monomer of a soluble, gel-free butadiene polymer or butadiene/styrene copolymer, and in the presence of to 200 parts by weight of a solvent per 100 parts by weight of monomers E) and F), wherein the solvent is an aliphatic (Cl-C 8 or cycloaliphatic (C 5 -C 6 alcohol, ketone, ether, ester or nitrile (Al) or a mixture of (Al) with an aliphatic (C 4 Clo), cycloaliphatic or aromatic hydrocarbon (A2) in a ratio by weight of A1:A2 from 100:0 to 30:70, and the polymerisation is conducted as far as a polymer content of the total mixture of 30 to 70% by weight, with thorough mixing and optionally with the subsequent addition of regulators and initiator, so that the isolated thermoplastic moulding composition contains 20 to by weight of the butadiene polymer. 5. ABS moulding compositions according to claims 1 to 4, characterised in that o: component was produced by solution polymerisation using at least one solvent selected from an aliphatic or cycloaliphatic Ci-C 8 alcohol, ketone, ether, ester, nitrile, or a mixture of at least one of said solvents with an aliphatic or cycloaliphatic C 4 -Co 0 hydrocarbon and/or aromatic hydrocarbon. 6. The use of the ABS moulding compositions according to claims 1 to 4 for the production of mouldings. P:\WPDOCS\Hij.Sp-679442PgS.d.23110/OI 18A 7. Moulding compositions substantially as hereinbefore described with reference to the Examples. DATED this 23rd day of October 2001 BAYER AKTIENGESELLSCHAFT' By its Patent Attorneys DAVIES COLLISON CAVE