EP1341845A2

EP1341845A2 - Thermoplastic moulding materials

Info

Publication number: EP1341845A2
Application number: EP01984756A
Authority: EP
Inventors: Herbert Eichenauer
Original assignee: Bayer AG
Current assignee: Styrolution Jersey Ltd
Priority date: 2000-12-05
Filing date: 2001-11-23
Publication date: 2003-09-10
Also published as: US6646045B2; WO2002046304A2; JP4129394B2; CN1535297A; JP2004515595A; WO2002046304A3; AU2002233195A1; TW548311B; US20020103296A1; CN1247693C; DE10060411A1

Abstract

The invention relates to compositions containing graft polymers with various initiator systems, characterised by a combination of good viscosity and reduced opacity, enabling the amount of pigment required to colour the moulding material/composition to be reduced.

Description

Thermoplastic molding compounds

The invention relates to compositions which contain graft polymers prepared with different initiator systems and which are distinguished by a combination of good toughness and reduced opacity. This means that significantly lower amounts of pigment are required to color the composition / molding compound.

ABS molding compounds have been used in large quantities as thermoplastic resins for the production of all kinds of molded parts for many years. The range of properties of these resins can be varied within a wide range.

In view of the constantly increasing demands on plastic materials and new application areas, ABS polymers with special combinations of properties are increasingly required.

Such a special combination of properties relates to ABS polymers for the production of colored impact-resistant molded parts, in particular in the application area of housings and cover plates. Here, the smallest possible amounts of

Colorants are required to set the desired color, which e.g. can be achieved by a lower opacity of the polymer material and a lighter color in the non-colored state (low yellowness index).

When using the technology of emulsion polymerization, attempts are usually made to achieve the desired properties by combining various graft rubber components with a thermoplastic resin matrix.

For example, describe DE-A 24 20 357 and DE-A 24 20 358 the use of specific graft polymers obtained by persulfate initiation with defined

Values for, among other things, rubber contents, particle size, degree of grafting, polystyrene acrylonitrile Ratio in the graft polymers and in the styrene / acrylonitrile copolymer used to achieve improved values for toughness, machinability and surface gloss. Despite the relatively complicated production of these molding compositions, optimal toughness, flowability and toughness / gloss relationships as well as insufficient inherent colors are not achieved.

Similar problems are found in the products produced according to EP-A 470 229, EP-A 473 400 and WO 91/13118, whereby by combining a graft polymer obtained by redox initiation with a low rubber content and low particle diameter with one obtained by redox initiation

Graft polymers with a high rubber content and larger particle diameter, shock-resistant, high-gloss thermoplastic resins can be obtained. However, the thermoplastic flow properties and the opacities of these molding compositions do not meet the constantly increasing requirements for such materials.

DE-A 41 13 326 describes thermoplastic molding compositions with two different graft products, the rubber contents of the graft rubbers each being a maximum of 30% by weight. The specification does not give more precise information on the properties; the variability of the products or the product properties is likely to be severely limited due to the low rubber content of the graft polymers.

DE-A 196 49 255 teaches the production of ABS molding compositions with very high gloss numbers while maintaining good values for toughness and machinability. a combination of a coarse particle produced by persulfate initiation

Graft polymer and a finely divided graft polymer produced by persulfate initiation, while observing special values for particle size distribution and gel content of the rubbers used. Disadvantages of these products are, in addition to the necessary compliance with numerous parameters during manufacture, the not always sufficient toughness values, inadequate inherent color and excessive opacity.

The object was therefore to provide compositions of the ABS type which do not have the disadvantages mentioned above, which have a combination of good toughness, a low yellowness index and reduced opacity and whose other properties are not intended to be adversely affected.

Even small reductions in opacity, which can be determined very precisely, lead to a noticeable reduction in the amount of pigment required to color the molding compositions.

The invention relates to compositions containing

A) at least one graft rubber produced by radical emulsion polymerization of at least one vinyl monomer, preferably styrene and acrylonitrile in a weight ratio of 90:10 to 50:50, it being possible for styrene and / or acrylonitrile to be replaced in whole or in part by α-methylstyrene, methyl methacrylate or N-phenylmaleimide, particularly preferably from

Styrene and acrylonitrile in the presence of at least one rubber present in latex form a) with a glass transition temperature below 0 ° C., preferably a butadiene rubber present in latex form, particularly preferably polybutadiene, using at least one peroxodisulfate compound as initiator,

B) at least one graft rubber produced by radical emulsion polymerization of at least one vinyl monomer. preferably of styrene and acrylonitrile in a weight ratio of 90:10 to 50:50, with styrene and / or acrylonitrile being able to be replaced in whole or in part by α-methylstyrene, methyl methacrylate or N-phenylmaleimide, particularly preferably of styrene and acrylonitrile in the presence of at least one rubber present in latex form b) with a glass transition temperature below 0 ° C., preferably a butadiene rubber present in latex form, particularly preferably polybutadiene, using at least one suitable azo compound as initiator and optionally

C) at least one thermoplastic rubber-free polymer obtained by polymerizing at least one resin-forming vinyl monomer, preferably styrene and acrylonitrile in a weight ratio of 90:10 to 50:50, it being possible for styrene and / or acrylonitrile to be replaced in whole or in part by α-methylstyrene, methyl methacrylate or N-phenyl.

In general, the compositions according to the invention can contain the graft rubbers A) and B) in any proportions, usually in the range from 5 to 95 parts by weight of A) and 95 to 5 parts by weight of B); 20 to 90 are preferred

Parts by weight of A) and 10 to 80 parts by weight of B), 30 to 80 parts by weight of A) and 20 to 70 parts by weight of B) are particularly preferred, and 40 to 75 parts by weight are very particularly preferred. Parts A) and 25 to 60 parts by weight B) (each based on 100 parts by weight A + B).

The optionally used thermoplastic rubber-free vinyl polymer C) can be used in amounts of 50 to 2000 parts by weight, preferably 100 to 1500 parts by weight and particularly preferably 150 to 1000 parts by weight (in each case based on 100 parts by weight of A + B ) are used.

The graft rubber polymers A) and B) used preferably have rubber contents of more than 50% by weight, more preferably more than 55% by weight, and very particularly preferably more than 58% by weight.

In addition, the compositions cannot contain other rubber-free ones

Contain thermoplastic resins built up vinyl monomers, whereby these thermo- plastic resins in amounts up to 1000 parts by weight, preferably up to 700 parts by weight and particularly preferably up to 500 parts by weight (in each case based on 100 parts by weight of A + B + C).

The one used to produce the graft rubber A) is in latex form

Rubber a) and the rubber b) present in latex form for the production of the graft rubber B) can be in the form of latices with monomodal, bimodal, trimodal or multimodal particle size distribution.

Combinations of graft rubbers A) and B) are preferred in which

Production of at least one of the rubber latices a) and b) used has a bimodal or trimodal particle size distribution.

Combinations of graft rubbers A) and B) are particularly preferred in which the rubber latex a) used has a monomodal particle size distribution and the rubber latex b) has a bimodal particle size distribution or the rubber latex a) uses a monomodal particle size distribution and the rubber latex used b) has a trimodal particle size distribution or in the production thereof the rubber latex a) has a bimodal particle size distribution and the rubber latex b) has a bimodal particle size distribution or in the production thereof the rubber latex a) has a bimodal particle size distribution and the rubber latex b) has a trimodal particle size distribution or in the production thereof, the rubber latex used a) has a bimodal particle size distribution and the rubber latex used b) has a monomodal part size distribution.

Combinations of graft rubbers A) and B) are particularly preferred in which the rubber latex a) used has a monomodal particle size distribution and the rubber latex b) has a bimodal particle size distribution or the rubber used latex a) has a bimodal particle size distribution and the rubber latex used b) has a bimodal particle size distribution. The average particle diameters (d ₅ o-Werf) of the monomodal, bimodal, trimodal or multimodal rubber latices a) and b) used to produce the graft rubbers A) and B) can be varied within wide ranges. Suitable particle diameters are, for example, between 50 and 600 nm, preferably between 80 and 550 μm and particularly preferably between 100 and 500 nm.

Preferably, the average particle diameter (i.e. ₅ o) of the Kaut- used schuklatices a) is smaller than the average particle diameter (d ₅ o) of the inserted

Rubber latices b), particularly preferably the average particle diameters of the rubber latices a) and b) used differ by at least 40 nm, very particularly preferably by at least 80 nm.

In principle, all rubber polymers with a glass transition temperature below 0 ° C. are suitable for the preparation of the graft rubbers according to component A) and component B) in rubber form a) and b). Examples of such rubber polymers are polydienes such as e.g. Polybutadiene and polyisoprene, alkyl acrylate rubbers based on Ci-Cg alkyl acrylates such as e.g. Poly-n-butyl acrylate, polysiloxane rubbers such as e.g. Products based on polydimethylsiloxane.

Preferred rubbers a) and b) for the production of the graft rubbers A) and B) are butadiene polymer latices which can be prepared by emulsion polymerization of butadiene. This polymerization process is known and e.g. in

Houben-Weyl, Methods of Organic Chemistry, Macromolecular Substances, Part 1, p. 674 (1961), Thieme Verlag Stuttgart. Up to 50% by weight, preferably up to 30% by weight (based on the total amount of monomers used for butadiene polymer preparation) of one or more monomers copolymerizable with butadiene can be used as comonomers. Examples and preferred for such monomers are isoprene, chloroprene, acrylonitrile, styrene, α-methylstyrene, C 1 -C 4 -alkylstyrenes, C 1 -C 6 -alkyl acrylates, C 1 -C 6 -alkyl methacrylates. Called alkylene glycol diacrylates, alkylene glycol dimethacrylates, divinylbenzene; butadiene is preferably used alone. In the production of a) and b) it is also possible to first produce a finely divided butadiene polymer by known methods and then to agglomerate it in a known manner to adjust the required particle size. Relevant techniques have been described (see EP-A 0 029 613; EP-A 0 007 810; DD-A 144 415; DE-A 12 33 131; DE-A 12 58 076; DE-A 21 01 650; US- A 1 379 391).

In principle, the rubber latices a) and b) can also be prepared by emulsifying finely divided rubber polymers in aqueous media (cf. Japanese patent application 55 125 102).

To produce rubber latices a) and b) with bimodal, trimodal or multimodal particle size distributions, preferably monomodal rubber latices of different average particle sizes and narrow particle size distributions are mixed together.

Monomodal rubber latices with a narrow particle size distribution within the meaning of the invention are understood to mean those latices which have a width of the particle size distribution (measured as d ₉ or _aus o from the integral particle size distribution) of 30 to 150 nm, preferably of 35 to 100 nm and particularly preferably of 40 have up to 80 nm.

The differences in the mean particle diameters (d ₅₀ value from the integral particle size distribution) of the rubber latices used for the mixing in the preferred production of bimodal, trimodal or multimodal particle size distributions are preferably at least 30 nm, particularly preferably at least 60 nm and very particularly preferably at least 80 nm. Monomodal rubber latices with a narrow particle size distribution are preferably produced by emulsion polymerization of suitable monomers, preferably butadiene-containing monomer mixtures, particularly preferably butadiene, by the so-called seed polymerization technique, in which a finely divided polymer, preferably a rubber polymer, particularly preferably a butadiene polymer, and then as a latex are prepared by further conversion with rubber-forming monomers, preferably with monomers containing butadiene, to further polymerize to larger particles (see, for example, in Houben-Weyl, Methods of Organic Chemistry, Macromolecular Substances Part 1, p.339 (1961), Thieme Verlag Stuttgart).

It is preferably carried out using the seed batch process or the seed feed process.

The gel contents of those used to produce the graft rubbers A) and B)

Rubber latices a) and b) are generally not critical and can be varied over a wide range. Usually values between approx. 30% and 98%, preferably between 40% and 95%, are set.

The gel contents of the rubber latices a) used are preferably higher than that

Gel contents of the rubber latices b) used, particularly preferably the gel contents of the rubber latices a) and b) used differ by at least 5%, very particularly preferably by at least 10%.

The determination of the mean particle diameter d ₅ o and the dio and d ₉ o

Values can be determined by ultracentrifuge measurement (cf. W. Scholtan, H. Lange: Kolloid Z. and Z. Polymer 250, pp. 782 to 796 (1972)), the values given for the gel content relate to the determination according to Wire cage method in toluene (cf. Houben-Weyl, Methods of Organic Chemistry, Macromolecular Substances, Part 1, p. 307 (1961), Thieme Verlag Stuttgart). The gel contents of the rubber latices a) and b) can be adjusted in a manner known in principle by using suitable reaction conditions (for example high reaction temperature and / or polymerization up to high conversion and, if appropriate, addition of crosslinking substances to achieve a high gel content or, for example, low reaction temperature and / or termination of the polymerization reaction before excessive crosslinking occurs and optionally addition of molecular weight regulators such as n-dodecyl mercaptan or t-dodecyl mercaptan to achieve a low gel content). As the emulsifier, conventional anionic emulsifiers such as alkyl sulfates, alkyl sulfonates, aralkyl sulfonates, soaps of saturated or unsaturated fatty acids and alkaline disproportionated or hydrogenated abietic or tall oil acids may be used, preferably emulsifiers ₈ fatty acids with carboxyl groups (for example salts of Cιo-Cι, disproportionated abietic acid ) used.

The graft polymerization in the preparation of the graft rubbers A) and B) can be carried out in such a way that the monomer mixture is added in portions or continuously to the rubber latex a) or to the rubber latex b) and polymerized.

Special monomer: rubber ratios are preferred.

In order to produce the graft rubber A) according to the invention, inorganic persalts selected from ammonium peroxodisulfate, potassium peroxodisulfate, sodium peroxodisulfate or mixtures thereof must be used.

The reaction temperature in the preparation of the graft rubber A) according to the invention can be varied within wide limits. It is generally 25 ° C. to 160 ° C., preferably 40 ° C. to 100 ° C. and particularly preferably 50 ° C. to 90 ° C., the temperature difference between the start and end of the reaction being at least 10 ° C., preferably at least 15 ° C. and is particularly preferably at least 20 ° C. To produce the graft rubber B) according to the invention, at least one suitable azo compound must be used as an initiator.

Azo compounds suitable according to the invention are, for example, compounds of the formulas (I), (II), (III) and (TV):

with R = CH ₃ , C ₂ H ₅ , C ₃ H ₇ , C ₄ H ₉

where the isomeric residues nC ₃ H ₇ , iC ₃ H ₇ , nC ₄ H ₉ , iC ₄ H ₉ , t-QHg are included,

CH, CH,

H 3, C - C 1 - N = N - C I - CH 3, (πi),

CN COOCH,

CH, CH, CH, CH,

H ₃ C- -C— CH, -C 1 - N = N— C 1 - CH «5-— C 1 - -CH, (IV)

I

OCH, CN CN OCH,

Preferred azo compounds suitable according to the invention are compounds of

Formula (I), compounds (I) with R = CH ₃ , C ₂ H ₅ , C ₄ H ₉ are particularly preferred. The reaction temperature in the preparation of the graft rubber B) according to the invention can be varied within wide limits. It is generally 25 ° C. to 120 ° C., preferably 35 ° C. to 100 ° C. and particularly preferably 40 ° C. to 85 ° C., the temperature difference between the start and end of the reaction being at least 10 ° C., preferably at least 15 ° C and particularly preferably at least 20 ° C.

To produce the graft rubber A) according to the invention, preferably 20 to 60 parts by weight, particularly preferably 25 to 50 parts by weight, and very particularly preferably 25 to 42 parts by weight, of at least one vinyl monomer, preferably a mixture of styrene and acrylonitrile , where styrene and or acrylonitrile can be replaced in whole or in part by α-methylstyrene, methyl methacrylate or N-phenylmaleimide, in the presence of preferably 40 to 80 parts by weight, particularly preferably 50 to 75 parts by weight and very particularly preferably 58 to 75 parts by weight (based on solids) of a rubber latex a) polymerized.

To produce the graft rubber B) according to the invention, preferably 25 to 70 parts by weight, particularly preferably 30 to 60 parts by weight and very particularly preferably 30 to 42 parts by weight, of at least one vinyl monomer, preferably a mixture of styrene and acrylonitrile, where styrene and / or acrylonitrile can be replaced in whole or in part by α-methylstyrene, methyl methacrylate or N-phenylmaleimide, in the presence of preferably 30 to 75 parts by weight, particularly preferably 40 to 70 parts by weight and very particularly preferably 58 to 70 parts by weight (based in each case on solids) of a rubber latex b) polymerized.

The monomers used in these graft polymerizations are preferably mixtures of styrene and acrylonitrile in a weight ratio of 90:10 to 50:50, particularly preferably in a weight ratio of 80:20 to 65:35.

In addition, molecular weight regulators can be used in the graft polymerization, preferably in amounts of 0.05 to 2% by weight, particularly preferably in Amounts of 0.1 to 1 wt .-% (each based on the total amount of monomer in the graft polymerization stage).

Suitable molecular weight regulators are, for example, alkyl mercaptans such as n-dodecyl mercaptan, t-dodecyl mercaptan; dimeric α-methylstyrene; Terpinolene.

The rubber-free copolymers C) used are preferably copolymers of styrene and acrylonitrile in a weight ratio of 95: 5 to 50:50, styrene and / or acrylonitrile being able to be replaced in whole or in part by α-methylstyrene, methyl methacrylate or N-phenylmaleimide.

Copolymers C) with proportions of incorporated acrylonitrile units of <30% by weight are particularly preferred.

These copolymers preferably have average molecular weights M _w of

20000 to 200000 or intrinsic viscosities [η] of 20 to 110 ml / g (measured in dimethylformamide at 25 ° C).

Details of the production of these resins are described, for example, in DE-A 2420 358 and DE-A 2 724360. Vinyl resins produced by bulk or solution polymerization have proven particularly useful. The copolymers can be added alone or in any mixture.

In addition to thermoplastic resins made up of vinyl monomers, the use of polycondensates, e.g. aromatic polycarbonates, aromatic polyester carbonates, polyesters, polyamides as a rubber-free copolymer possible in the compositions according to the invention.

Suitable thermoplastic polycarbonates and polyester carbonates are known (cf., for example, DE-A 1 495 626, DE-A 2 232 877, DE-A 2703 376, DE-A 2714 544, DE-A 3,000 610, DE-A 3 832 396, DE-A 3 077 934), for example producible by reacting diphenols of the formulas (V) and (VI)

embedded image in which

a single bond, -CC ₅ alkylene, C ₂ -C ₅ alkylene, C ₅ -C ₆ cycloalkyl idene, -O-, -S-, -SO-, -SO ₂ - or -CO- .

R ⁵ and R ⁶ independently of one another represent hydrogen, methyl or halogen, in particular hydrogen, methyl, chlorine or bromine,

R ¹ and R ² independently of one another hydrogen, halogen preferably chlorine or

Bromine, Ci-Cg-alkyl, preferably methyl, ethyl, C ₅ -C ₆ cycloalkyl, preferably cyclohexyl, Cg-Cio-aryl, preferably phenyl, or Cy-C ^ aralkyl, preferably phenyl-C ₁ -C alkyl , in particular benzyl, mean

m is an integer from 4 to 7, preferably 4 or 5,

n is 0 or 1, R ³ and R ⁴ are individually selectable for each X and are independently hydrogen or Ci-Cg-alkyl and

X means carbon

with carbonic acid halides, preferably phosgene, and / or with aromatic dicarboxylic acid dihalides, preferably benzenedicarboxylic acid dihalides, by phase interface polycondensation or with phosgene by polycondensation in a homogeneous phase (the so-called pyridine process), the molecular weight being adjusted in a known manner by an appropriate amount of known chain terminators can be.

Suitable diphenols of the formulas (N) and (VI) are e.g. Hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, 2,2-bis (4-hydroxyphenyl) propane, 2,4-bis (4-hydroxyphenyl) -2-methylbutane, 2,2-bis ( 4-hydroxy-3,5-dimethylphenyl) propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) -propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3-dimethylcyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5,5-tetramethylcyclohexane or 1,1-bis (4-hydroxyphenyl) -2,4,4, - trimethylcyclopentane.

Preferred diphenols of the formula (V) are 2,2-bis (4-hydroxyphenyl) propane and l, l-bis (4-hydroxyphenyl) cyclohexane, preferred phenol of the formula (VI) is 1,1-bis- (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane.

Mixtures of diphenols can also be used.

Suitable chain terminators are, for example, phenol, p-tert-butylphenol, long-chain alkylphenols such as 4- (1,3-tetramethylbutyl) phenol according to DE-A 2 842005, monoalkylphenols, dialkylphenols with a total of 8 to 20 carbon atoms in the alkyl substituents according to DE-A 3 506 472, such as p-Νonylphenol, 2,5-di-tert-butylphenol, p-tert- Octylphenol, p-dodecylphenol, 2- (3,5-dimethylheptyl) phenol and 4- (3,5-dimethylheptyl) phenol. The amount of chain terminators required is generally 0.5 to 10 mol%, based on the sum of the diphenols (V) and (VT).

The suitable polycarbonates or polyester carbonates can be linear or branched; branched products are preferably obtained by incorporating 0.05 to 2.0 mol%, based on the sum of the diphenols used, of three or more than three-functional compounds, e.g. those with three or more than three phenolic OH groups.

The suitable polycarbonates or polyester carbonates can contain aromatically bound halogen, preferably bromine and / or chlorine; they are preferably halogen-free.

They have average molecular weights (M _w , weight average) determined, for example, by

Ultracentrifugation or scattered light measurement from 10,000 to 200,000, preferably from 20,000 to 80,000.

Suitable thermoplastic polyesters are preferably polyalkylene terephthalates, i.e. reaction products made from aromatic dicarboxylic acids or their reactive derivatives (e.g. dimethyl esters or anhydrides) and aliphatic, cycloaliphatic or arylaliphatic diols and mixtures of such reaction products.

Preferred polyalkylene terephthalates can be prepared from terephthalic acids (or their reactive derivatives) and aliphatic or cycloaliphatic diols with 2 to 10 carbon atoms by known methods (Kunststoff-Handbuch, Volume Viπ, p. 695 ff, Carl Hanser Verlag, Munich 1973). In preferred polyalkylene terephthalates, 80 to 100, preferably 90 to 100 mol% of the dicarboxylic acid residues, terephthalic acid residues and 80 to 100, preferably 90 to 100 mol% of the diol residues are 1,4-ethylene glycol and / or butanediol residues.

The preferred polyalkylene terephthalates can contain, in addition to ethylene glycol or butanediol 1,4, residues from 0 to 20 mol% of residues of other aliphatic diols with 3 to 12 C atoms or cycloaliphatic diols with 6 to 12 C atoms, e.g. Residues of propanediol-1,3, 2-ethylpropanediol-1,3, neopentylglycol, pentanediol-1,5, hexanediol-1,6, cyclohexanedi-methanol-1,4,3-methylpentanediol-1,3 and -1 , 6, 2-ethyl-hexanediol-1,3, 2,2-diethylpropanediol-1,3, hexanediol-2,5,1,4-di (ß-hydroxyethoxy) benzene, 2,2-bis-4 -hydroxycyclohexyl) propane, 2,4-dihydroxy-1, 1, 3,3-tetramethyl-cyclobutane, 2,2-bis (3-ß-hydroxyethoxyphenyl) propane and 2,2-bis (4-hydroxypro poxyphenyl) propane (DE-A 2407 647, 2 407 776, 2715 932).

The polyalkylene terephthalates can be 3- or by incorporating relatively small amounts

Tetravalent alcohols or 3- or 4-based carboxylic acids, as described in DE-A 1 900 270 and US-A 3 692 744, are branched. Examples of preferred branching agents are trimesic acid, trimellitic acid, trimethyl olethane and propane and pentaerythritol. It is advisable not to use more than 1 mol% of the branching agent, based on the acid component.

Particularly preferred are polyalkylene terephthalates which have been produced solely from terephthalic acid and its reactive derivatives (e.g. its dialkyl esters) and ethylene glycol and / or 1,4-butanediol and mixtures of these polyalkylene terephthalates.

Preferred polyalkylene terephthalates are also copolyesters which are produced from at least two of the abovementioned alcohol components: particularly preferred copolyesters are poly (ethylene glycol butanediol-1.4) terephthalates. The preferably suitable polyalkylene terephthalates generally have an intrinsic viscosity of 0.4 to 1.5 dl / g, preferably 0.5 to 1.3 dl / g, in particular 0.6 to 1.2 dl / g, each measured in Phenol / o-dichlorobenzene (1: 1 parts by weight) at 25 ° C.

Suitable polyamides are known homopolyamides, copolyamides and mixtures of these polyamides. These can be partially crystalline and / or amorphous polyamides.

Polyamide-6, polyamide-6,6, mixtures and corresponding copolymers of these components are suitable as partially crystalline polyamides. Also suitable are partially crystalline polyamides, the acid component of which is wholly or partly composed of terephthalic acid and / or isophthalic acid and / or suberic acid and / or sebacic acid and / or azelaic acid and / or adipic acid and / or cyclohexanedicarboxylic acid, the diamine component wholly or partly of m- and / or p -Xylylene diamine and / or hexamethylene diamine and / or 2,2,4-trimethylhexamethylene diamine and / or 2,2,4-trimethylhexamethylene diamine and / or isophorone diamine and the composition of which is known in principle.

In addition, mention should be made of polyamides which are wholly or partly prepared from lactams with 7- 12 C atoms in the ring, optionally with the use of one or more of the above-mentioned starting components.

Particularly preferred partially crystalline polyamides are polyamide 6 and polyamide 6,6 and their mixtures. Known products can be used as amorphous polyamides. They are obtained by polycondensation of diamines such as ethylenediamine, hexamethylenediamine, decamethylenediamine, 2,2,4- and or 2,4,4-trimethylhexamethylenediamine, m- and / or p-xylylenediamine, bis- (4- aminocyclohexyl) methane, bis- (4-aminocyclohexyl) propane, 3,3'-dimethyl-4,4'-diamino-di-cyclohexylmethane, 3-aminomethyl, 3,5,5, -trimethylcyclohexylamine, 2, 5- and / or 2,6-bis (aminomethyl) norbornane and / or 1,4-diaminomethylcyclohexane with dicarboxylic acids such as oxalic acid, adipic acid, azelaic acid, azelaic acid, decanedicar bonic acid, heptadecanedicarboxylic acid, 2,2,4- and / or 2,4,4-trimethyladipic acid, isophthalic acid and terephthalic acid.

Copolymers which are obtained by polycondensation of several monomers are also suitable, furthermore copolymers which are prepared with the addition of aminocarboxylic acids such as ε-aminocaproic acid, ω-aminoundecanoic acid or ω-aminolauric acid or their lactams.

Particularly suitable amorphous polyamides are the polyamides prepared from isophthalic acid, hexamethylene diamine and other diamines such as 4,4'-diaminodicyclohexyl methane, isophorone diamine, 2,2,4- and / or 2,4,4-trimethylhexamethylene diamine, 2, 5- and / or 2,6-bis (aminomethyl) norbornene; or from isophthalic acid, 4,4'-diamino-dicyclohexylmethane and ε-caprolactam; or from isophthalic acid, 3,3'-dimethyl-4,4'-diamino-dicyclohexylmethane and laurolactam; or from terephthalic acid and the isomer mixture of 2,2,4- and / or 2,4,4-trimethylhexamethylene diamine.

Instead of the pure 4,4'-diaminodicyclohexylmethane, it is also possible to use mixtures of the positionally isomeric diaminodicyclohexylmethanes which are composed of one another

70 to 99 mol% of the 4,4'-diamino isomer 1 to 30 mol% of the 2,4'-diamino isomer 0 to 2 mol% of the 2,2'-diamino isomer and

if appropriate, correspondingly more highly condensed diamines obtained by hydrogenating technical-grade diaminodiphenylmethane. Up to 30% of the isophthalic acid can be replaced by terephthalic acid. The polyamides preferably have a relative viscosity (measured on a 1% strength by weight solution in m-cresol at 25 ° C.) from 2.0 to 5.0, particularly preferably from 2.5 to 4.0.

Preferred compositions according to the invention contain 1 to 60 parts by weight, preferably 5 to 50 parts by weight of graft rubber components A) + B) and 40 to 99 parts by weight, preferably 50 to 95 parts by weight of rubber-free thermoplastic polymer C).

If there are additional rubber-free vinyl monomers

Thermoplastic resins are used, the amount is up to 1000 parts by weight, preferably up to 700 parts by weight and particularly preferably up to 500 parts by weight (in each case based on 100 parts by weight of A + B + C).

The compositions according to the invention are prepared by mixing components A), B) and C) and, if appropriate, further constituents on conventional mixing units (preferably on multi-roll mills, mixing extruders or internal kneaders).

The invention therefore furthermore relates to a process for the preparation of the compositions according to the invention, components A), B) and C) and, if appropriate, further constituents being mixed and compounded and extruded at elevated temperature, generally at from 150 to 300.degree ,

The necessary or appropriate additives, for example antioxidants, UV stabilizers, peroxide destroyers, antistatic agents, lubricants, mold release agents, flame retardants, fillers or reinforcing materials (glass fibers, carbon fibers, etc.) and colorant. The final deformation can be carried out on commercially available processing units and includes, for example, injection molding processing, sheet extrusion with subsequent hot forming, cold forming, extrusion of tubes and profiles or calendar processing.

Examples

In the following examples, the parts given are always parts by weight and the% given are always% by weight, unless stated otherwise.

Components used

A) Graft rubbers produced using peroxodisulfate compounds as initiators

A 1) 60 parts by weight (calculated as solids) of a radical polymerization prepared anionically emulsified monomodal polybutadiene latex having an average particle diameter d ₅ o of 112 nm and a gel content of 91 wt .-% are diluted with water to a solids content of about Brought 20 wt .-%. The mixture is then heated to 59 ° C and with 0.45 parts by weight

K ₂ S ₂ O ₈ (dissolved in water) was added. Then, within 6 hours, 40 parts by weight of a monomer mixture (part by weight of styrene-acrylonitrile = 73:27), 0.12 part by weight of tert-dodecyl mercaptan and 1.0 part by weight (calculated as the solid substance) ) of the sodium salt of a resin acid mixture (Dresinate® 731, Abieta Chemie GmbH, Gersthofen), dissolved in alkaline water.

The reaction temperature is raised to 80 ° C. in the course of 6 hours, after which a 2-hour post-reaction time at this temperature follows. After adding about 1 part by weight of a phenolic antioxidant, the mixture is coagulated with a magnesium sulfate / acetic acid mixture and, after washing with water, the resulting powder is dried at 70.degree.

A 2) The procedure described under A 1) is repeated, using a bimodal polybutadiene latex with an average particle diameter d ₅ o of 158 nm (Particle size peaks at 112 nm and at 285 nm) and a gel content of 86% by weight is used.

A 3) The procedure described under AI) is repeated, using a bimodal polybutadiene latex with an average particle diameter d ₅ o of 202 nm

(Particle size peaks at 112 nm and at 285 nm) and a gel content of 82% by weight is used.

A 4) The procedure described under A 1) is repeated, wherein a mono- modal polybutadiene latex having an average particle diameter d ₅ o of

191 nm and a gel content of 69 wt .-% is used.

A 5) The procedure described under A I) is repeated, using a bimodal

Polybutadiene latex having an average particle diameter d ₅ o (nm particle size peaks at 191 and 285 nm) of 216 nm and a gel content of

70 wt .-% is used.

A 6) The procedure described under A 1) is repeated, using a bimodal

D polybutadiene latex having an average particle diameter of ₅ o (nm particle size peaks at 191 and 285 nm) of 240 nm and a gel content of

71 wt .-% is used.

A 7) The procedure described under AI) is repeated, using a bimodal polybutadiene latex with an average particle diameter d ₅ o of 245 nm (particle size peaks at 199 nm and at 285 nm) and a gel content of

81 wt .-% is used.

A 8) The procedure described under A 1) is repeated, using a monomodal polybutadiene latex with an average particle diameter d ₅ o of 285 nm and a gel content of 72% by weight. A 9) The procedure described under A 1) is repeated, using a bimodal polybutadiene latex with an average particle diameter d ₅ o of 350 nm (particle size peaks at 285 nm and at 415 nm) and a gel content of 70 wt .-% is used.

A 10) The procedure described under A 1) is repeated, using a monomodal polybutadiene latex having an average particle diameter d ₅ o of 415 nm and a gel content of 70 wt .-% is used.

B) Graft rubbers made using azo initiators

B 1) 60 parts by weight (calculated as solids) of a radical polymerization prepared anionically emulsified monomodal polybutadiene latex having an average particle diameter d ₅ o of 285 nm and a Gelge- halt of 72 wt .-% are diluted with water to a solids content of approx. 20

% By weight. The mixture is then heated to 59 ° C., and 1 part by weight of the compound (I) with R = C ₂ H ₅ (Vazo 67, DuPont Deutschland GmbH, Bad Homburg vdH) (dissolved in part of the monomer mixture) is added. Thereafter, 40 parts by weight of a monomer mixture (styrene: acrylonitrile weight ratio = 73:27), 0.12 part by weight of -dodecyl mercaptan and 1.38 parts by weight (are calculated in parallel within 6 hours as solid matter) of the sodium salt of a resin acid mixture (Dresinate 731 ^®, Abieta Chemie GmbH, Gersthofen) dissolved in alkaline water adjusted, metered.

The reaction temperature is raised to 80 ° C. in the course of 6 hours, after which there is a 2-hour post-reaction time at this temperature. After adding about 1 part by weight of a phenolic antioxidant, the mixture is coagulated with a magnesium sulfate / acetic acid mixture and, after washing with water, the resulting powder is dried at 70.degree. B 2) The procedure described under B 1) is repeated, using a bimodal polybutadiene latex with an average particle diameter d ₅ o of 350 nm (particle size peaks at 285 nm and at 415 nm) and a gel content of 70 wt .-% is used.

B 3) The procedure described under B 1) is repeated, using a monomodal polybutadiene latex with an average particle diameter d ₅₀ of 415 nm and a gel content of 70% by weight.

C) Thermoplastic resins

C 1) Styrene / Acrylonitrile (SAN) - Produced by Solution Polymerization

Copolymer resin (weight ratio of styrene-acrylonitrile = 72: 28, M _w »85,000, determined by gel permeation chromatography).

C 2) Styrene / acrylonitrile (SA) - prepared by solution polymerization

Copolymer resin (weight ratio styrene: acrylonitrile = 72: 28, M _w «115,000, determined by gel permeation chromatography).

Testing the molding compounds

The polymer components described above are mixed in the proportions given in Table 1, 2 parts by weight of ethylenediamine bisstearylamide and 0.1 part by weight of a silicone oil in an internal kneader and, after granulation, to test bars and to a flat plate (for assessing the surface and the contrast ratio, dimensions 60 x 40 x 2 mm) processed.

The following data are determined:

Notched impact strength at room temperature (a (RT)) and at -20 ° C (a _k (-20 ° C)) according to ISO 180/1 A (unit: kJ / m ² ),

Heat resistance (Vicat B) according to DIN 53 460 (unit: ° C), Surface gloss according to DIN 67 530 at a reflection angle of 20 ° (reflectometer value),

Yellowness index (YI) according to ASTM standard D 1925 (illuminant: C, observer: 2 °, measuring aperture: large area value) according to the equation YI = (128X - 106Z) / Y, with X, Y, Z = color coordinates according to DIN 5033,

Contrast ratio (CR) as a measure of the opacity of the material by measuring a sample against a black and a white background in accordance with

rτ> = Y (against a black background) I QQ Y (against a white background)

where Y describes the standard color value from the CIElab color space with illuminant D 65 and 10 ° observer (see DIN 5033, Ulbricht sphere). The measurement was carried out using a Dataflash SF 600 plus CT spectrophotometer.

The processability of the molding compositions was assessed by measuring the required filling pressure at 240 ° C. (unit: bar) (see S. Anders et al., Kunststoffe 81 (1991), 4, pages 336 to 340 and the literature cited therein).

The results are summarized in Table 2.

It can be seen from this that the molding compositions according to the invention have significantly improved toughness values, lower yellowness index values and lower opacity values in direct comparison with the respective comparative example, and therefore the amount of pigment required to set the desired color is significantly reduced. Other important properties such as heat resistance, thermoplastic processability and surface gloss are not adversely affected. Table 1: Compositions of the molding compounds tested

Table 2: Test values of the compositions examined

Claims

claims

1. Containing composition

A) at least one graft rubber made by radical

Emulsion polymerization of at least one vinyl monomer in the presence of at least one rubber present in latex form a) with a glass transition temperature below 0 ° C. using at least one peroxodisulfate compound as initiator,

B) at least one graft rubber prepared by radical emulsion polymerization of at least one vinyl monomer in the presence of at least one rubber present in latex form b) with a glass transition temperature below 0 ° C. using at least one azo compound as initiator and optionally

C) at least one thermoplastic rubber-free polymer obtained by polymerizing at least one resin-forming vinyl monomer.

2. Composition according to claim 1 containing

A) at least one graft rubber produced by radical emulsion polymerization of styrene and acrylonitrile in a weight ratio of 90:10 to 50:50, wherein styrene and / or acrylonitrile can be replaced in whole or in part by α-methylstyrene, methyl methacrylate or N-phenylmaleimide in the presence at least a butadiene rubber in latex form using at least one peroxodisulfate compound as initiator, B) at least one graft rubber prepared by radical emulsion polymerization of styrene and acrylonitrile in a weight ratio of 90:10 to 50:50, it being possible for styrene and / or acrylonitrile to be replaced in whole or in part by α-methylstyrene, methyl methacrylate or N-phenylmaleimide in the presence of at least one Butadiene rubber present in latex form using at least one azo compound as initiator and optionally

C) at least one thermoplastic rubber-free polymer obtained by polymerizing styrene and acrylonitrile in a weight ratio of 90:10 to 50:50, it being possible for styrene and or acrylonitrile to be replaced in whole or in part by α-methylstyrene, methyl methacrylate or N-phenylmaleimide.

Compositions according to Claims 1 and 2, in which component B) is prepared by initiation with an azo compound selected from the group of the compounds of the formulas (I), (II), (III) - and (IV):

CH ",

3 C "H '3,

R— C— = N— C— R (I)

CN CN

R = CH ₃ , C ₂ H ₅ , nC ₃ H ₇ , iC ₃ H ₇ , nC ₄ H ₉ , iC ₄ H ₉ , t-C + Hg

(IV)

or mixtures thereof.

4. Compositions according to claims 1 to 3, containing 20 to 90 wt .-% A) and 10 to 80 wt .-% B).

5. Compositions according to the preceding claims containing 30 to 80 wt .-% A) and 20 to 70 wt .-% B).

6. Compositions according to claim 4 additionally containing 50 to 2000 parts by weight of C) (per 100 parts by weight of A) + B)).

7. Compositions according to claim 5 additionally contain 100 to 1500

Parts by weight C) (per 100 parts by weight A) + B)).

8. Compositions according to the preceding claims additionally containing at least one resin selected from aromatic polycarbonate, aromatic polyester carbonate, polyester, polyamide or mixtures thereof.

9. Compositions according to the preceding claims, wherein in each case a rubber latex with a monomodal particle size distribution is used to produce the graft rubbers A) and B).

10. Compositions according to claims 1 to 8, wherein in each case a rubber latex with a bimodal particle size distribution is used to produce the graft rubbers A) and B).

11. Compositions according to claims 1 to 8, wherein a rubber latex with a monomodal particle size distribution is used to produce the graft rubber A) and a rubber latex with a bimodal particle size distribution is used to produce the graft rubber B).

12. Compositions according to claims 1 to 8, wherein a rubber latex with monomodal particle size distribution is used to produce the graft rubber A) and a rubber latex with trimodal particle size distribution is used to produce the graft rubber B).

13. Compositions according to claims 1 to 8, wherein a rubber latex with a bimodal particle size distribution is used to produce the graft rubber A) and a rubber latex with a trimodal particle size distribution is used to produce the graft rubber B).

14. Compositions according to claims 1 to 8, wherein a rubber latex with a bimodal particle size distribution is used for the production of the graft rubber A) and a rubber latex with a monomodal particle size distribution is used for the production of the graft rubber B).

15. Compositions according to the above claims, characterized in that for the production of the graft rubbers A) and B) rubber latices having mean particle diameters (d ₅ o) are used from 50 to 600 nm.

16. Compositions according to the above claims, characterized in that for the production of the graft rubbers A) and B) rubber latices having mean particle diameters (d ₅ o) of 100 to 500 nm are used.

17. Compositions according to claims 15 and 16, characterized in that the average particle diameter (d ₅ o) of the rubber latex used to produce the graft rubber A) is smaller than the average particle diameter (d ₅ o) of the rubber latex used to produce the graft rubber B) ,

18. Use of the compositions according to claims 1 to 17 for the production of moldings.

19. Moldings obtainable from compositions according to claims 1 to 17.

20. A process for the preparation of compositions, characterized in that

A) at least one graft rubber prepared by radical emulsion polymerization of at least one vinyl monomer in the presence of at least one rubber present in latex form a) with a glass transition temperature below 0 ° C. using at least one peroxodisulfate compound as initiator,

C) at least one thermoplastic rubber-free polymer obtained by polymerizing at least one resin-forming vinyl monomer

mixed and compounded at elevated temperature.