WO1998032796A1

WO1998032796A1 - High-tenacity thermoplastic moulding materials

Info

Publication number: WO1998032796A1
Application number: PCT/EP1998/000199
Authority: WO
Inventors: Graham Edmund Mc Kee; Bernhard Rosenau; Heiner GÖRRISSEN; Ekkehard Jahns
Original assignee: Basf Aktiengesellschaft
Priority date: 1997-01-27
Filing date: 1998-01-15
Publication date: 1998-07-30
Also published as: EP0954551A1; CN1251120A; JP2001508821A; KR20000070463A; DE19702733A1

Abstract

The invention relates to thermoplastic moulding materials containing A) 30-98 wt.% of a thermoplastic polymer comprising, in relation to A), a1) 50-100 wt.% of a styrene compound of general formula (I), in which R?1 and R2¿ stand for hydrogen or C¿1?-C8-alkyl, or of a (C1-C8 alkyl) ester of acrylic acid or of methacrylic acid, or mixtures of the styrene compounds and the (C1-C8-alkyl) ester of acrylic acid or methacrylic acid, a2) 0-40 wt.% acrylonitrile or methacrylonitrile or their mixtures, and a3) 0-40 wt.% of one or several other monoethylene unsaturated monomers that are different from a2), B) 1-69 wt.% of a first particle-shaped rubber-elastic polymer B) with a particle diameter d50 of average weight of 300 nm or less, C) 1-69 wt.% of a second particle-shaped rubber-elastic polymer C) with an average-volume particle diameter d50 between 700 nm and 100 νm, whereby the polymer C) is obtainable by the microsuspension polymerization method, by i) dispersion of the monomers corresponding to the polymer C) in water using at least one protective colloid to form a dispersion of droplets with an average-volume particle diameter d50 between 700 nm and 100 νm, and (ii) polymerization of the droplets by means of a radical polymerization initiator, and D) 0-80 wt.% of one or several other polymers.

Description

Thermoplastic molding compounds with high toughness

description

The present invention relates to thermoplastic molding compositions containing

containing thermoplastic molding compositions

A) 30 to 98% by weight of a thermoplastic polymer, based on A)

al) 50 to 100% by weight of a styrene compound of the general formula

R2

in which R ¹ and R ^{2 represent} hydrogen or Ci-Cs-alkyl,

or

one (Ci-Cs-alkyl) ester of acrylic acid or methacrylic acid,

or mixtures of the styrene compound and the (Ci-Cs-alkyl) ester of acrylic acid or methacrylic acid,

a2) 0 to 40% by weight of acrylonitrile or methacrylonitrile or mixtures thereof, and

a3) 0 to 40% by weight of one or more further monoethylenically unsaturated monomers different from a2),

B) 1 to 69% by weight of a first particulate rubber-elastic polymer B) with a weight-average

Particle diameter dso ^on 300 nm or below,

C) 1 to 69% by weight of a second particulate, rubber-elastic polymer C) with a volume-average particle diameter dso of 700 nm to 100 μm, the polymer C) is obtainable by the process of microsuspension polymerization

i) dispersing the monomers corresponding to polymer C) in water using at least one protective colloid to form a dispersion of droplets with a volume-average particle diameter dso of 700 nm to 100 μm, and

ii) polymerization of the droplets using a radical polymerization initiator,

and

D) 0 to 80% by weight of one or more further polymers.

The invention also relates to special molding compositions in which the polymers B) and C) are graft polymers P), and to processes for the production of particulate polymers, graft polymers and thermoplastic molding compositions.

Finally, the invention relates to the use of the molding compositions for the production of moldings and the moldings produced therefrom.

DE-PS 34 22 919 molding compounds made of a poly (styrene-acrylonitrile) matrix, and two graft rubbers with particle sizes of 100 to 450 nm on the one hand and 500 to 5000 nm on the other hand are known, the large-part graft rubber in mass or mass / suspension will be produced. The mechanical properties of these molding compounds are not satisfactory in all respects, and the molded parts have a high gloss.

EP-A 326 024 teaches similar molding compositions containing a small-part (50 to 600 nm) and a large-part (700 to 10,000 nm) graft polymer based on rubbers, the latter being produced in bulk or in solution. However, the production of this so-called solution ABS is lengthy since it takes a long time to dissolve the polybutadiene rubber in the graft monomers.

DE-OS 41 31 728 discloses molding compositions composed of a poly (styrene-acrylonitrile) matrix, a small-part (50 to 200 nm) and a large-part (300 to 1500 nm) graft polymer made from alkyl acrylate rubbers. The large graft particles are made in emulsion. Because they tend to coagulate under the conditions of emulsion polymerization, it is often difficult to set the desired particle size. One also observes in in some cases exudation of the emulsifiers used for the production from the molded part (deposit formation).

US Pat. No. 3,652,721 describes molding compositions from the matrix mentioned, a small-part (less than 250 nm) and a large-part (350 to 1000 nm) graft rubber polymer, the large-part rubber being produced by agglomeration of smaller, emulsion-based ones Latex particles is obtained. The agglomerated particles tend to uncontrolled coagulation. As described, emulsifiers can exude from the moldings.

DE-OS 44 43 886 discloses large-part graft rubber polymers with average particle sizes from 1 to 100 μm, which are produced by the microsuspension polymerization process,

15 and molding compositions containing these particles, a poly (styrene-acrylonitrile) matrix, and graft rubber particles. The use of the large-scale microsuspension graft polymers results in molded parts with matt surfaces, but these graft polymers do not significantly improve the mechanical

20 niche properties: the impact strength of molded parts with and without microsuspension particles are comparable.

The object of the invention was to remedy the shortcomings described. In particular, the task was to prepare molding compositions

25 to deliver, which are characterized by good mechanical properties and at the same time by a precisely adjustable surface gloss. In particular, molding compositions should be provided which are characterized by a combination of high impact strength, in particular notched impact strength, and uniform mattness of the surface,

Mark 30.

We have found that this object is achieved by the thermoplastic molding compositions defined at the outset. Furthermore, special molding compositions in which the polymers B) and C) are graft polymers P) and processes for the production of particulate polymers and graft polymers were found, and the use of the molding compositions for the production of moldings and the moldings produced therefrom.

40 With regard to the proportions of the components, it should be noted that the sum of components A), B), C) and D) adds up to 100% by weight.

Component A) is present in the molding compositions in a proportion of 30 to 98, preferably 45, 36 to 96 and particularly preferably 40 to 96% by weight, based on the sum of components A) to D). Component A) is obtained by polymerizing a monomer mixture based on A),

al) 50 to 100, preferably 60 to 95 and particularly preferably 60 to 90% by weight of a styrene compound of the general formula I.

in which R ¹ and R ^{2 represent} hydrogen or Ci -Cs alkyl

or

one (-C-Co, -alkyl) ester of acrylic acid or methacrylic acid

a2) 0 to 40, preferably 5 to 38% by weight of acrylonitrile or methacrylonitrile or mixtures thereof, and

a3) 0 to 40, preferably 0 to 30% by weight of one or more further monoethylenically unsaturated monomers different from a2).

Component A) preferably has a glass transition temperature T _g of 50 ° C. or above. A) is therefore a hard polymer.

The styrene compound of the general formula (I) (component a1)) is preferably styrene, α-methylstyrene and, moreover, styrenes which are core-alkylated with C 1 -C 6 -alkyl, such as p-methylstyrene or tert-butylstyrene. Styrene is particularly preferred. Mixtures of the styrenes mentioned, in particular styrene and α-methylstyrene, can also be used.

Instead of the styrene compounds or in a mixture with them, ci- to Ce-alkyl esters of acrylic acid and / or methacrylic acid come into consideration, especially those which are derived from methanol, ethanol, n- and iso-propanol, sec.-, tert.- and iso -Butanol, pentanol, hexanol, heptanol, octanol, 2-ethylhexanol and n-butanol. Methyl methacrylate is particularly preferred.

Component A) may also contain one or more further monoethylenically unsaturated monomers a3) at the expense of monomers al) and a2), which the mechanical and thermal Properties of A) vary within a certain range. Examples of such comonomers are:

N-substituted maleimides such as N-methyl, N-phenyl and N-cyclohexyl maleimide;

Acrylic acid, methacrylic acid, furthermore dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid and their anhydrides such as maleic anhydride;

Nitrogen-functional monomers such as dimethylaminoethyl acrylate, diethylaminoethyl acrylate, vinylimidazole, vinylpyrrolidone, vinylcaprolactam, vinylcarbazole, vinylaniline, acrylamide and methacrylamide;

aromatic and araliphatic esters of acrylic acid and methacrylic acid such as phenyl acrylate, phenyl methacrylate, benzyl acrylate, benzyl methacrylate, 2-phenylethyl acrylate, 2-phenylethyl methacrylate, 2-phenoxyethyl acrylate and 2-phenoxyethyl methacrylate;

unsaturated ethers such as vinyl methyl ether,

as well as mixtures of these monomers.

Preferred components A) are, for example, polystyrene, and

Copolymers of styrene and / or α-methylstyrene and one or more of the other monomers mentioned under al) to a3). Methyl methacrylate, N-phenylmaleimide, maleic anhydride and acrylonitrile are preferred, methyl methacrylate and acrylonitrile being particularly preferred.

Examples of preferred components A are:

A / l polystyrene A / 2 copolymer of styrene and acrylonitrile,

A / 3 copolymer of α-methylstyrene and acrylonitrile,

A / 4 copolymer of styrene and methyl methacrylate.

The proportion of styrene or α-methylstyrene, or the proportion of the sum of styrene and α-methylstyrene, is particularly preferably at least 40% by weight, based on component A).

If component A) preferably contains styrene and acrylonitrile, the known commercially available SAN copolymers are formed. They usually have a viscosity number VZ (determined according to

DIN 53 726 at 25 ° C, 0.5 wt. - in dimethylformamide) from 40 to 160 ml / g, corresponding to an average molecular weight of about 40,000 to 2,000,000 (weight average).

Component A) can be used in a manner known per se, e.g. obtained by substance, solution, suspension, precipitation or emulsion polymerization. Details of these methods are e.g. in the plastics handbook, ed. Vieweg and Daumiller, Carl-Hanser-Verlag Munich, vol. 1 (1973), pp. 37 to 42 and vol. 5 (1969), pp. 118 to 130, as well as in Ulimann's encyclopedia of technical chemistry, 4th edition, Verlag Chemie Weinheim, Vol. 19, pp. 107 to 158 "Polymerizationstechnik" described.

Component B) is present in the molding compositions in a proportion of 1 to 69, preferably 2 to 62 and in particular 2 to 58% by weight, based on the sum of components A) to D). Component B) is a first particulate, rubber-elastic polymer with a weight-average particle diameter of dso of 300 nm or less. All those monomers or monomer mixtures which give rubber-elastic polymers can be used as monomers for the preparation of B).

The suitable rubber-elastic polymers B) preferably have a glass transition temperature of below 0 ° C., particularly preferably below -10 ° C. and very particularly preferably below -20 ° C. Accordingly, they are "soft" polymers.

Monomers suitable for the preparation of the polymers B) are, for example

conjugated dienes, such as butadiene, or isoprene, alkyl esters of acrylic acid or methacrylic acid, such as n-butyl acrylate, 2-ethylhexyl acrylate and other (C 1 -C ₀ -alkyl) acrylates - monomers which polymerize to form crosslinked silicone rubbers, for example dimethylsiloxane,

or mixtures of these monomers.

Further details on preferred components B), provided they are made up of dienes or alkyl acrylates, in particular the type and amount of the monomers used, are given below.

Suitable cross-linked silicone rubbers are generally crosslinked silicone rubbers of units of the general formulas R ₂ SiO, RSi0 _{_3/2,} R ₃ SiOι / and Si0 ₂ / where R is a monovalent radical, and in the case of R ₃ SiOj_ / optionally also OH, represents. The amounts of the individual siloxane units are usually such that for 100 units of the formula R ₂ SiO 0 to 10 mol units of the formula RSi0 / ₂ , 0 to 1.5 mol units R ₃ SiOι / ₂ and 0 to -3 molar units of Si0 _{_2/4} are present.

R generally represents Ci-Ciβ-alkyl, preferably C ₁ -C ₁₂ , particularly preferably Cχ-C ₆ -alkyl such as methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, tert-butyl, pentyl or hexyl, in particular methyl or ethyl or C ₆ -C -o-aryl such as phenyl or naphthyl, in particular phenyl, or Cχ-Cιo-alkoxy and aryloxy such as methoxy, ethoxy or phenoxy, preferably methoxy, or groups which can be attacked by free radicals, such as vinyl, allyl, acrylic, acryloxy, methacrylic, methacryloxyalkyl, halogen or mercapto groups, preferably vinyl or mercapto-C ₁ -C 8 -alkyl radicals, in particular mercaptopropyl, vinyl and methacryloxypropyl.

In a particular embodiment, silicone rubbers are used in which at least 80% of all R radicals are methyl radicals. Silicone rubbers in which R represents methyl and ethyl are also preferred.

In a further embodiment, silicone rubbers are used which contain the abovementioned groups which can be attacked by free radicals in amounts in the range from 0.01 to 10, preferably from 0.2 to 2, mol%, based on all the R radicals. Such silicone rubbers are described, for example, in EP-A 260 558 and in EP-A 492 376.

Furthermore, the silicone rubbers described in DE-A 25 39 572 can be used as resins, or those known from EP-A 370 347.

The first rubber-elastic polymer B) is available in a manner known per se. The polymer B) is preferably by the process of emulsion polymerization, e.g. at 30 to 80 ° C.

Suitable emulsifiers for this purpose are, for example, alkali metal salts of alkyl or alkylarylsulfonic acids, alkyl sulfates, fatty alcohol sulfonates, salts of higher fatty acids with 10 to 30 carbon atoms, sulfosuccinates, ether sulfonates or resin soaps. The alkali metal salts of alkyl sulfonates or fatty acids having 10 to 18 carbon atoms are preferably used. Sufficient water is preferably used to prepare the dispersion so that the finished dispersion has a solids content of 20 to 50% by weight.

Free radical formers, for example peroxides such as preferably peroxosulfates (for example potassium persulfate) and azo compounds such as azodiisobutyronitrile, are suitable as polymerization initiators. However, redox systems, in particular those based on hydroperoxides such as cumene hydroperoxide, can also be used.

Molecular weight regulators such as e.g. Use ethylhexylthio glycolate, t-dodecyl mercaptan, terpinols and dimeric α-methyl styrene.

To maintain a constant pH value, which is preferably 6 to 9, buffer substances such as Na ₂ HP0 ₄ / NaH ₂ P0 or sodium bicarbonate can also be used.

Emulsifiers, initiators, regulators and buffer substances are used in the usual amounts, so that further details are not necessary.

The polymers B) can particularly preferably also be polymerized by the monomers in the presence of a finely divided

Produce rubber latex (so-called "seed latex procedure" of the polymerization, described e.g. in DE-OS 28 26 925).

In principle, it is also possible to prepare the polymers B) by a process other than that of emulsion polymerization, e.g. by bulk or solution polymerization and, if appropriate, subsequently emulsifying the polymers obtained. Microsuspension polymerization is also suitable, preference being given to using oil-soluble initiators such as lauroyl peroxide and t-butyl perpivalate. The procedures for this are known.

The reaction conditions are coordinated with one another in a manner known per se so that the polymer particles B) have a weight-average particle diameter dso of 300 nm or less, preferably 250 nm or less, particularly preferably 220 nm or less . This applies regardless of whether the polymers B) are produced in emulsion or in another way (e.g. in bulk or in solution).

Component C) is present in the molding compositions in a proportion of 1 to 69, preferably 2 to 62 and particularly preferably 2 to 58% by weight, based on the sum of components A) to D). at component C) is a second particulate rubber-elastic polymer with a volume-average particle diameter d ₅ o of 700 nm to 100 μm.

All those monomers or monomer mixtures which give rubber-elastic polymers and which can be polymerized by free radicals, that is to say polymerize in the presence of so-called “free radicals”, can be used as monomers for the preparation of C).

Suitable monomers have already been mentioned by way of example for the first, small-particle polymer B).

The suitable rubber-elastic polymers C) preferably have a glass transition temperature of below 0 ° C., particularly preferably below -10 ° C. and very particularly preferably below -20 ° C. Accordingly, they are "soft" polymers.

Further details on preferred components C), provided they are composed of dienes or alkyl acrylates, in particular the type and amount of the monomers used, are given below. With regard to silicone rubbers as polymer C), reference is made to the corresponding explanations for component B).

According to the invention, the second, large-part rubber-elastic polymer C) is produced by the microsuspension polymerization process.

In this process, the monomers M (or the monomer mixture M) which correspond to the desired polymer C) are converted into

Water disperses using at least one protective colloid SK, so that a dispersion of the monomer droplets in water with a volume-average droplet diameter dso of 700 nm to

100 μm is created.

After that, the droplets are removed by means of a radical

Polymerization initiator RI polymerizes.

The process of microsuspension polymerization is described in more detail below.

Usually, the amount of water in which the monomers M and the protective colloids SK are dispersed is 25 to 95% by weight, preferably 40 to 85% by weight and particularly preferably 45 to 75% by weight, based on the Sum of monomers, water and protective colloids. The protective colloids SK which are suitable for stabilizing the dispersion are water-soluble polymers which coat the monomer droplets and the polymer particles formed therefrom and in this way protect them against coagulation.

Suitable protective colloids SK are cellulose derivatives such as carboxymethylcellulose and hydroxymethylcellulose, poly-N-vinylpyrrolidone, polyvinyl alcohol and polyethylene oxide, anionic polymers such as polyacrylic acid and their copolymers and cationic polymers such as poly-N-vinylimidazole. The amount of these protective colloids is preferably 0.1 to 10% by weight, based on the total mass of the emulsion.

Protective colloids and methods for producing protective colloids are known per se and are described, for example, in Encyclopedia of Polymer Science and Engineering, vol. 16, p. 448, published by John Wiley, 1989.

One or more polyvinyl alcohols are preferably used as the protective colloid, in particular those with a degree of hydrolysis below 96 mol%, particularly preferably 60 to 94 and very particularly preferably 65 to 92 mol%. The preferred polyvinyl alcohols have a viscosity of 2 to 100 mPa / s, in particular 4 to 60 mPa / s, measured as a 4% by weight solution in water at 20 ° C. according to DIN 53015.

In addition to the protective colloids, colloidal silica in a concentration of generally 0.2 to 5% by weight, based on the amount of the dispersion, can also be used. More about this method, which works particularly well with a water-soluble polymer of adipic acid and diethanolamine as a protective colloid, can be found in US Pat. No. 3,615,972.

In order to suppress the simultaneous emulsion polymerization process in microsuspension polymerization, in which much smaller and therefore undesirable particles are formed, a water-soluble inhibitor can be used which suppresses the emulsion polymerization. Effective connections of this type are e.g. Chromium (+6) compounds like potassium dichromate.

An emulsion is prepared from the monomers M, water and the protective colloids SK by allowing high shear forces to act. Homogenizers known to those skilled in the art are used for this. Examples include:

Laboratory dissolver Dispermat, VMA-Getzmann, Reichshof, DE Ultra-Turax, -Fa. Janke and Kunkel, Staufen, DE - pressure homogenizer, Gaulin, Lübeck, DE Devices with a rotor-stator system, approximately

Dispax, from Janke and Kunkel, Staufen, DE Cavitron homogenizers, from v. Hagen & Funke, Sprochhövel, DE - homogenizers from Kotthoff, Essen, DE

Homogenizers from Dorr Oliver, Grevenbroich, DE.

Usually, these devices operate at speeds from 1000 to 25,000 min ^"1, preferably from 2000 to 15,000 min ^-1.

Furthermore, the high shear forces can also

Exposure to ultrasound,

Pressing the mixture of monomers, water and protective colloids under high pressure through a narrow gap or through nozzles of small diameter colloid mills

or other suitable homogenizers are generated.

The dispersion is usually prepared at room temperature, but depending on the type of monomers and protective colloids, higher or lower temperatures may also be useful.

The dispersion can be prepared either batchwise (batch mode) or continuously. In the case of discontinuous production, monomers, water and protective colloids are placed in a container and mixed to form a microsuspension (dispersion) using the homogenizer.

The homogenizer can also be arranged parallel to the container and the components are circulated through the homogenizer.

The duration of homogenization can be between 0.1 sec and several hours, depending on, for example, the desired diameter of the monomer droplets and the size distribution to be set, the mixing of the monomers with water, the quantitative ratios of monomer, water and protective colloid, and the protective colloid used. It is also possible to add the total amount of monomers and the total amount of water, and to add the protective colloids when the homogenizer is started.

In the continuous preparation of the dispersion, in a preferred embodiment, the monomers, water and protective colloids can be fed to the homogenizer and the dispersion prepared in this way can be fed directly into the reactor in which the polymerization is carried out.

In another preferred embodiment of the continuous dispersion preparation, monomers, water and protective colloids are circulated through the homogenizer and only part of the circulated mixture is branched off and fed to the polymerisation reactor. This circular procedure is particularly recommended if the dispersion of the monomers is still insufficient after only a single throughput through the homogenizer, for example if the droplet size is too large and / or the size distribution is too wide.

In a further preferred embodiment, the finished dispersion can be temporarily stored in a storage container before the polymerization and metered from the storage container into the polymerization reactor. This makes it possible to carry out dispersion and polymerization spatially separated from one another, for example, in a large-scale application of the method in different buildings.

In a further embodiment, the dispersion can also be produced discontinuously in a first step and continuously in a second step: the components are dispersed as a batch as described, and the resulting dispersion is then subjected to a second, continuously carried out dispersion. This creates the finished dispersion, which is fed continuously to the reactor.

Additives which impart specific properties to the particulate polymers C) can be added before or during the preparation of the dispersion. Examples of such additives are polymers, dyes and pigments.

The additives are usually distributed very uniformly in the resulting dispersion by the homogenizer, so that after the polymerization the additives are generally contained uniformly in the particles. The proportion of additives is generally at least 0.5% by weight, preferably at least 5% by weight and particularly preferably at least 10% by weight, based on the mixture fed to the homogenizer. -

The polymerization is initiated with a radical polymerization initiator RI. Such compounds are known to the person skilled in the art.

Compounds with a half-life of one are preferred

Hour when the temperature is 60 to 110 ° C and which are noticeably soluble in the monomers.

In particular, organic peroxides, azo compounds and / or compounds with C-C single bonds are used as initiators RI. Monomers which polymerize spontaneously at elevated temperature are also used as radical polymerization initiators.

Mixtures of the initiators RI mentioned can also be used.

In the case of the peroxides, those with hydrophobic properties are preferred, in particular those molecules with an atomic ratio of carbon to oxygen of greater than 3: 1. Dilauryl peroxide and dibenzoyl peroxide, in particular dilauryl peroxide, are very particularly preferred.

As azo compounds, 2,2'-azobis (2-methylbutyronitrile) and 2,2'-azobis (isobutyronitrile) are preferred. As compounds with labile C-C bonds, preference is given to using 3,4-dimethyl-3,4-diphenylhexane and 2,3-dimethyl-2,3-diphenylbutane.

Monomers which polymerize spontaneously at elevated temperature are preferably styrene and its derivatives, such as vinyl toluene, particularly preferably styrene.

The amount of initiator RI is usually 0.05 to 4, preferably 0.1 to 2 and particularly preferably 0.3 to 1% by weight, based on the amount of the monomers M. These amounts of course do not apply in the event that the monomer is also an initiator, such as styrene.

Depending on the physical state of the initiator and its solubility behavior, it can be used as such, but preferably as a solution, dispersion (liquid in liquid) or suspension (solid in liquid) are added, which means that small amounts of initiator in particular can be metered more precisely.

Organic solvents such as, for example, benzene, toluene, ethylbenzene and cyclohexane, in particular cyclohexane, or else the monomers themselves are suitable as the solvent or liquid phase for the initiator. When the monomers themselves are used as the solvent or liquid phase for the initiator, the Initiator dissolved or emulsified / suspended in the total amount of the monomers or preferably in a smaller portion of the monomers, and this portion then added to the remaining components.

It is also possible to dissolve the initiator in the solvent or in the monomer and to disperse the resulting solution in water.

The amount of solvent or liquid phase in which the initiator RI is dissolved, emulsified or suspended is preferably selected such that the concentration of the initiator in the finished solution or dispersion / suspension is preferably at least 5% by weight, preferably is at least 8% by weight and particularly preferably at least 10% by weight.

The initiator (s) RI can be added before or after the preparation of the dispersion, or only immediately before the start of the polymerization, or can be metered in continuously in the course of the polymerization.

In the case of monomers which tend to undergo uncontrolled polymerization or which polymerize even at the temperature of the dispersion preparation, it is advisable not to use the initiator RI until after the emulsification, possibly. only to be added immediately before the polymerization.

In the case of polymerizations with a long polymerization time in particular, it may be advantageous to add the initiator as a continuous feed or in portions during the polymerization. The duration of the initiator feed can be different or the same as the duration of the polymerization.

Buffer substances such as Na ₂ HP0 / NaH ₂ P0 or Na citrate / citric acid can be used as further additives in the polymerization in order to set an essentially constant pH. Molecular weight regulators, for example mercaptans such as t-dodecyl mercaptan, or ethylhexylthioglycolate can also be used.

These further additives can be added continuously or discontinuously at the beginning and / or during the preparation of the dispersion and / or during the polymerization.

The polymerization is carried out in the usual manner, for example by heating the reactor contents, whereby the polymerization reaction is started. If necessary, the initiator RI can only then be added, that is to say to the heated dispersion. The polymerization temperature depends, among other things. on the monomers and initiators used and on the desired degree of crosslinking of the resulting particulate polymers C). Polymerization is generally carried out at from 30 to 120 ° C., it also being possible to set different temperatures or a temperature gradient in succession.

The polymerization reaction is usually carried out with slow or moderate stirring, in which (in contrast to the previous emulsification by high shear forces) the droplets are no longer broken down.

According to a preferred embodiment, the polymerization of the monomer droplets containing the monomers M is completed without the addition of other monomers M * - other than the monomers M. In this case, particle-shaped polymers C) are obtained which are constructed essentially homogeneously (uniform distribution of the monomer units in the particle).

In another preferred embodiment, the polymerization of the monomers M is carried out up to a conversion of more than 50%, based on the monomers M used, after which one or more further monomers M * are added and polymerized. This results in particulate polymers C) having a two-phase structure, one phase containing the polymerized monomers M and the other phase containing the polymerized monomers M *. These two-phase polymers C) often have an approximately core-shell structure, the core of the monomers M and the shell containing the monomers M *.

However, the core-shell structure is generally not complete, since the core, that is to say the inner phase, usually contains a considerable proportion of polymerized “shell” monomers M *. The polymers present in the inner phase and built up from monomers M * are often present as so-called “inclusions”. It is therefore not referred to below as the core and shell, but rather as phases or basic level and graft level.

As a rule, but not necessarily, the polymerization of the further monomers M ^{* represents} a grafting reaction (graft polymerization) as is known to the person skilled in the art. The resulting two-phase particles are then graft particles. In the case of the regularly occurring graft polymerization in the core, as described above, one speaks of "inner graft polymers".

In this case of the graft polymerization, the monomers M correspond to the basic stage p1) mentioned below and the monomers M * correspond to the grafting stage p2) mentioned below.

The polymerization of the monomers M is preferably carried out up to a conversion of at least 65%, particularly preferably up to a conversion of at least 80%, in each case based on the monomers M used, before the further monomers M * are added and polymerized.

If, according to one embodiment, the further monomers M * are added before the monomers M have been completely converted into the corresponding polymer (conversion of M below 100%), the remaining monomers M and the added further monomers M * are polymerized at the same time. This gives two-phase polymers with a gradual transition from the basic stage (from monomers M) to the graft stage (from monomers M *), a so-called "smeared" transition.

If, in another embodiment, the further monomers M * are added and polymerized only after the monomers M have completely converted, particles are obtained with a sharp transition from the basic stage to the grafting stage.

In one embodiment, the further monomers M * are added batchwise as a single or repeated addition, or in another embodiment continuously as a feed.

In a further embodiment, the further monomers M * can be added to the reactor one after the other in several stages of the polymerization, the monomers M * of each stage differing from one another. Particles with several phases are obtained in this way. The monomers M * of a polymerization stage are polymerized up to a conversion of more than 50%, preferably at least 65% and particularly preferably at least 80%, based on the monomers M ^* used in the respective stage, before monomers again in the next polymerization stage M * can be added.

As already described, the transition between the individual phases of the resulting multi-phase particle is sharper the more complete the conversion of the monomers M * is before the monomers M * are added to the next stage.

With regard to the polymerization conditions (temperature, additives), reference is made to the comments on the polymerization of the monomers M, which also apply analogously to the reaction of the monomers M *.

In particular, it may be expedient to add further protective colloids SK discontinuously or continuously before and / or during the polymerization of the monomers M ^{*, the} protective colloids being different from those used for producing the core. However, the polyvinyl alcohols described are preferably used again.

Furthermore, it may be expedient to add further radical polymerization initiators RI discontinuously or continuously before and / or during the polymerization of the monomers M *, the initiators being able to be the same or different from those used to prepare the core.

The further monomers M * can be added to each stage batchwise (all at once) or continuously (as feed).

The monomers M * generally differ from the monomers M. If, for example, monomers M are used which give a more elastomeric, "soft" polymer, then monomers M ^{* used are} those which give a "hard" polymer. This gives a particulate polymer P with a soft phase and a hard phase. Such polymers are preferred, as will be explained further below.

Multiphase polymers can be obtained in the same way, for example the hard phase structure - soft phase - hard phase, if different monomers M * are added and polymerized in succession in several stages as described. In the event that the monomers M (for one phase) do not differ in type from the monomers M * (for the other phase (s)), the quantitative ratios of the monomers M in the monomer mixture are out which one phase arises differs from the quantitative ratios of the monomers M * in the monomer mixture from which the other phase arises.

The volume-average diameter (dso) of the particulate polymers C) from 700 nm to 100 μm is essentially determined by the diameter of the monomer droplets which arise during the preparation of the dispersion due to high shear force (and of course due to polymerized shells, if present).

The polymers C) according to the invention have an average particle diameter (volume average) dso from 700 nm to 100 μm, preferably from 1000 nm to 100 μm. The polymers C) are preferably smaller than 50 μm, particularly preferably smaller than 30 μm (volume-average particle size dso)

The particle size can therefore essentially be controlled by appropriately selecting and controlling the conditions during the preparation of the dispersion (for example, choice of the homogenizer, duration of the homogenization, quantitative ratios of monomers: water: protective colloids, mode of dispersing (single, multiple, as batch or continuous, circular mode), speed of the homogenizer etc.).

After the end of the polymerization, the particulate polymers C) are dispersed in water. This dispersion can either be further processed as such, or the polymers C) can be separated from the aqueous phase. This work-up is carried out in a manner known per se, for example by sieving, filtering, decanting or centrifuging, it being possible for the polymer particles to be further dried in the customary manner, if necessary, for example by means of warm air, spray drying or by means of a current dryer.

In the molding compositions according to the invention, the weight ratio of the first rubber-elastic polymer B) to the second rubber-elastic polymer C) is preferably in a range from 2:98 to 98: 2, particularly preferably 3:97 to 97: 3 and very particularly preferably 5:95 to 95: 5.

In a preferred embodiment, both the first, small-part (weight-average dso value <300 nm) polymer B) and the second large-part (volume-average d ₅₀ value 700 nm to 100 μm) polymer C) are grafted Polymers P). These graft polymers P), ie the preferred embodiments of components B) and C), contain, based on P),

Pl) 30 to 95, preferably 40 to 90 and particularly preferably 40 to 85% by weight of a rubber-elastic basic stage, based on pl)

pll) 50 to 100, preferably 60 to 100 and particularly preferably 70 to 100% by weight of a (Ci-Cio-alkyl) ester of acrylic acid,

pl2) 0 to 10, preferably 0 to 5 and particularly preferably 0 to 2% by weight of a polyfunctional, crosslinking monomer,

pl3) 0 to 40, preferably 0 to 30 and particularly preferably 0 to 20% by weight of one or more further monoethylenically unsaturated monomers,

or off

pll *) 50 to 100, preferably 60 to 100 and particularly preferably 65 to 100% by weight of a diene with conjugated double bonds,

pl2 *) 0 to 50, preferably 0 to 40 and particularly preferably 0 to 35% by weight of one or more monoethylenically unsaturated monomers,

p2) 5 to 70, preferably 10 to 60 and particularly preferably 15 to 60% by weight of a graft stage, based on p2),

p21) 50 to 100, preferably 60 to 100 and particularly preferably 65 to 100% by weight of a styrene compound of the general formula

R ²

in which R ¹ and R ^{2 represent} hydrogen or d-Cs-alkyl, p22) 0 to 40, preferably 0 to 38 and particularly preferably 0 to 35% by weight of acrylonitrile or methacrylonitrile or mixtures thereof,

p23) 0 to 40, preferably 0 to 30 and particularly preferably 0 to 20% by weight of one or more further monoethylenically unsaturated monomers.

Suitable as (Ci-CiQ-alkyl) esters of acrylic acid, component pll) are, above all, ethyl acrylate, 2-ethylhexyl acrylate and n-butyl acrylate. Preferred are 2-ethylhexyl acrylate and n-butyl acrylate, and n-butyl acrylate is very particularly preferred. Mixtures of different alkyl acrylates which differ in their alkyl radical can also be used.

Crosslinking monomers pl2) are bifunctional or polyfunctional comonomers with at least two olefinic double bonds, for example butadiene and isoprene, divinyl esters of dicarboxylic acids such as succinic acid and adipic acid, diallyl and divinyl ethers of bifunctional alcohols such as ethylene glycol and

Butane-1,4-diols, diesters of acrylic acid and methacrylic acid with the bifunctional alcohols mentioned, 1,4-divinylbenzene and triallyl cyanurate. Particularly preferred are the acrylic acid ester of tricyclodecenyl alcohol (see DE-OS 12 60 135), which is known under the name dihydrodicyclopentadienyl acrylate, and the allyl esters of acrylic acid and methacrylic acid.

Crosslinking monomers pl2) may or may not be present in the molding compositions depending on the type of molding compositions to be produced, in particular depending on the desired properties of the molding compositions.

If crosslinking monomers pl2) are present in the molding compositions, the amounts are 0.01 to 10, preferably 0.3 to 8 and particularly preferably 1 to 5% by weight, based on pl).

The other monoethylenically unsaturated monomers p 13) which may be present in the graft core pl) at the expense of the monomers pll) and pl2) are, for example:

vinyl aromatic monomers such as styrene, styrene derivatives of the general formula

R ²

_Ri -C = CH ₂ in which R ¹ and R ^{2 represent} hydrogen or Ci- to Cβ-alkyl;

Acrylonitrile, methacrylonitrile;

Ci to C alkyl esters of methacrylic acid, such as methyl methacrylate, and also the glycidyl esters, glycidyl acrylate and methacrylate;

furthermore the monomers mentioned for component a3);

as well as mixtures of these monomers.

Preferred monomers pl3) are styrene, acrylonitrile, methyl methacrylate, glycidyl acrylate and methacrylate, acrylamide and methacrylamide.

Instead of the basic stage monomers pll) to pl3), the basic stage can also be constructed from the monomers pll *) and pl2 *).

Butadiene, isoprene, norbornene and their halogen-substituted derivatives, such as chloroprene, come into consideration as dienes with conjugated double bonds, p1 *). Butadiene and isoprene, in particular butadiene, are preferred.

The monomers which have already been mentioned for the monomers pl3) can also be used as further monoethylenically unsaturated monomers pl2 *).

Preferred monomers pl2 *) are styrene, acrylonitrile, methyl methacrylate, glycidyl acrylate and methacrylate, acrylamide and methacrylamide.

The graft core pl) can also be constructed from a mixture of the monomers pll) to pl3) and pll *) to pl2 *).

If the graft core contains the monomers pll) to pl3), then after mixing with a thermoplastic polymer A) from styrene and acrylonitrile (SAN), so-called ASA molding compounds (acrylonitrile styrene alkyl acrylate) are formed. If the graft core contains the monomers pll *) to pl2 *), then after mixing with a thermoplastic polymer A) from styrene and acrylonitrile (SAN), molding compounds of the ABS type (acrylonitrile-butadiene-styrene) are formed. In a preferred embodiment, the polymers B) and C) are ASA graft polymers or ABS graft polymers, or mixed types of ASA and ABS. With regard to the monomers p21) and p23), reference is made to the comments on components a1) and bl3). Accordingly, the graft shell p2) can contain further monomers p22) or p23) or mixtures thereof at the expense of the monomers p21). The graft shell p2) is preferably composed of polymers as mentioned as preferred embodiments A / 1 to A / 4 of component A).

The graft polymers P) can be obtained in a manner known per se, preferably by emulsion polymerization, as has already been described in detail for polymer B), or by microsuspension polymerization, as has been described in detail for polymer C).

The graft stage p2) can be produced under the same conditions as the preparation of the basic stage pl), it being possible to produce the graft stage p2) in one or more process steps. The monomers p21), p22) and p23) can be added individually or in a mixture with one another. The monomer ratio of the mixture can be constant over time or a gradient. Combinations of these procedures are also possible.

For example, you can first polymerize styrene alone, and then a mixture of styrene and acrylonitrile, to the basic stage p1).

The gross composition remains unaffected by the above-mentioned configurations of the method.

Graft polymers with several "soft" and "hard" stages, e.g. of the structure pl) -p2) -pl) -p2) or p2) -pl) -p2), especially in the case of larger particles.

To the extent that non-grafted polymers are formed from the monomers p2) during grafting, these amounts, which are generally below 10% by weight of p2), are assigned to the mass of component P), that is to say B) and C).

Component D) is present in the molding compositions in a proportion of 0 to 80, preferably 0 to 70 and particularly preferably 0 to 60% by weight, based on the sum of components A) to D). Component D) is a further polymer.

Polycarbonates, polyesters, polyamides or mixtures thereof are preferably used as further polymers. Suitable polycarbonates are known per se. They can be obtained, for example, in accordance with the processes in DE-B-1 300 266 by interfacial polycondensation or in accordance with the processes in DE-A-14 95 730 by reacting biphenyl carbonate with bisphenols. Preferred bisphenol is 2, 2-di (4-hydroxyphenyl) propane, generally - as also hereinafter - referred to as bisphenol A.

Instead of bisphenol A, other aromatic dihydroxy compounds can also be used, in particular 2,2-di (4-hydroxyphenyl) pentane, 2,6-dihydroxy naphthalene, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxydiphenyl ether, 4,4 '-Dihydroxy- diphenylsulfite, 4, 4' -Dihydroxydiphenylmethan, 1, 1-di- (4-hydroxyphenyDethan or 4, 4-Dihydroxydiphenyl and mixtures of the aforementioned dihydroxy compounds.

Particularly preferred polycarbonates are those based on bisphenol A or bisphenol A together with up to 30 mol. -% of the above-mentioned aromatic dihydroxy compounds.

The relative viscosity of these polycarbonates is generally in the range from 1.1 to 1.5, in particular 1.28 to 1.4 (measured at 25 ° C. in a 0.5% by weight solution in dichloroethane).

Suitable polyesters are also known per se and are described in the literature. They contain an aromatic ring in the main chain, which comes from an aromatic dicarboxylic acid. The aromatic ring can also be substituted, for example by halogen such as chlorine and bromine or by C 1 -C ₄ alkyl groups such as methyl, ethyl, i- or n-propyl and n-, i- or tert-butyl - groups.

The polyesters can be prepared in a manner known per se by reacting aromatic dicarboxylic acids, their esters or other ester-forming derivatives thereof with aliphatic dihydroxy compounds.

Preferred dicarboxylic acids are naphthalenedicarboxylic acid, terephthalic acid and isophthalic acid or mixtures thereof. Up to 10 mol% of the aromatic dicarboxylic acids can be replaced by aliphatic or cycloaliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acids and cyclohexanedicarboxylic acids. Of the aliphatic dihydroxy compounds, diols with 2 to 6 carbon atoms, in particular 1, 2-ethanediol, 1,4-butanediol, 1, 6-hexanediol, 1, 4-hexanediol, 1, 4-cyclohexanediol and neopentyl glycol or their mixtures preferred. 5

Polyalkylene terephthalates which are derived from alkanediols having 2 to 6 carbon atoms can be mentioned as particularly preferred polyesters. Of these, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate and polybutylene 10-naphthalate are particularly preferred.

Polybutylene terephthalate and polyethylene terephthalate are generally prepared in a manner known per se by condensation of terephthalic acid or its esters with butanediol or ethanediol

15 made under catalysis. The condensation is advantageously carried out in two stages (precondensation and polycondensation). Details can be found, for example, in Ulimann's Encyclopedia of Technical Chemistry, 4th edition, volume 19, pp. 61-88. Polybutylene terephthalate is for example as Ultradur ^®

20 (from BASF) commercially available.

The viscosity number of the polyesters is generally in the range from 60 to 200 ml / g (measured in a 0.5% strength by weight solution in a phenol / o-dichlorobenzene mixture (weight ratio 1: 1 at 25 25 ° C.) ).

Preferred polyamides are very generally those with an aliphatic partially crystalline or partially aromatic and amorphous structure of any kind and their blends. Corresponding products are available, for example, under the trade name Ultramid ^® from BASF AG.

In addition to polycarbonates, polyesters and polyamides, other polymers can also be used as component D), for example polysulfones, polyether sulfones, polypropylene, polyethylene, polybutene, polyoxymethylene, and thermoplastic polyurethanes (TPU). Their structure and their manufacture are known to the person skilled in the art.

Furthermore, the thermoplastic molding compositions may contain lubricants or mold release agents, pigments, dyes, flame retardants, anti-oxidants, light stabilizers, fibrous and powdery fillers or reinforcing agents or antistatic agents, and also other additives or mixtures thereof.

45 Suitable lubricants and mold release agents are, for example, stearic acids, stearyl alcohol, stearic acid esters or amides, as well as silicone oils, montan waxes and those based on polyethylene and polypropylene.

Pigments are, for example, titanium dioxide, phthalocyanines, ultramarine blue, iron oxides or carbon black, and the class of organic pigments.

Dyes are to be understood as all dyes which can be used for the transparent, semi-transparent or non-transparent coloring of polymers, in particular those which are suitable for coloring styrene copolymers. Dyes of this type are known to the person skilled in the art.

As flame retardants e.g. the halogen-containing or phosphorus-containing compounds known to the person skilled in the art, magnesium hydroxide and other customary compounds, or mixtures thereof, are used.

Suitable antioxidants (heat stabilizers) are, for example, sterically hindered phenols, hydroquinones, various substituted representatives of this group and mixtures thereof. They are commercially available as Topanol ^® or Irganox ^® .

Suitable light stabilizers are, for example, various substituted resorcinols, salicylates, benzotriazoles, benzophenones, HALS (Hindered Amine Light Stabilizers), as they are, for example commercially available as Tinuvin ^®.

Examples of fibrous or powdered fillers are carbon or glass fibers in the form of glass fabrics, glass mats or glass silk rovings, cut glass, glass balls and wollastonite, particularly preferably glass fibers. When using glass fibers, these can be equipped with a size and an adhesion promoter for better compatibility with the blend components. Glass fibers can be incorporated both in the form of short glass fibers and in the form of endless strands (rovings).

Suitable particulate fillers are carbon black, amorphous silica, magnesium carbonate (chalk), powdered quartz, mica, mica, bentonite, talc, feldspar or, in particular, calcium silicates such as wollastonite and kaolin. Suitable antistatic agents are, for example, amine derivatives such as N, N-bis (hydroxyalkyl) alkylamines or alkylene amines, polyethylene glycol esters or glycerol mono- and distearates, and mixtures thereof.

The individual additives are used in the usual amounts, so that further details are unnecessary.

The molding compositions according to the invention can be produced by mixing processes known per se, for example by melting in an extruder, Banbury mixer, kneader, roller mill or calender. However, the components can also be used "cold" and the powdery or granular mixture is only melted and homogenized during processing.

Components A), B), C) and D), if appropriate with the additives mentioned, are preferably mixed in an extruder or other mixing device at temperatures of 100 to 320 ° C. while melting, and discharged. The use of an extruder is particularly preferred.

Moldings (including foils) of all kinds can be produced from the molding compounds. The molded parts are characterized by a combination of good mechanical properties and precisely adjustable ones

Surface gloss. In particular, the moldings show high impact strength and uniformly matt surfaces at the same time.

The following explanations are to be added to the particle sizes mentioned:

The volume-average particle size is determined, for example, by taking light and electron microscopic images and measuring and counting the particles cut at the equator.

The weight average particle size d of component B) is the weight average of the particle size, as determined by means of an analytical ultracentrifuge according to the method of W. Scholtan and H. Lange, Kolloid-Z. and Z. Polymers 250 (1972) pages 782 to 796. The ultracentrifuge measurement provides the integral mass distribution of the particle diameter of a sample. From this it can be seen what percentage by weight of the particles have a diameter equal to or smaller than a certain size. The dχo "value indicates the particle diameter at which 10% by weight of all particles have a smaller and 90% by weight a larger diameter. Conversely, for the dg ₀ value, 90% by weight of all particles have a smaller and 10% by weight have a larger diameter than the diameter which corresponds to the dgo value The weight-average particle diameter dso or volume-average particle diameter dso indicates the particle diameter at which 50% by weight or volume% of all particles unite larger and 50% by weight or vol.% have a smaller particle diameter, din, dso and dgo values characterize the width Q of the particle size distribution, Q = (dgo-dio) / dso- the smaller Q, the narrower the distribution.

Examples

Deionized water was used

Production of component A: copolymer of styrene and acrylonitrile

A copolymer of 65% by weight of styrene and 35% by weight of acrylonitrile was produced by the process of continuous solution polymerization, as described in the plastic handbook, ed. R. Vieweg and G. Daumiller, vol. V "polystyrene ", Carl Hanser Verlag Munich 1969, pages 122 to 124, is described. The

Viscosity number VZ (determined according to DIN 53 726 at 25 ° C., 0.5% by weight in dimethylformamide) was 80 ml / g.

Production of a component B-1 (not according to the invention) Rubber-elastic graft polymer (core cross-linked poly-butyl acrylate, shell of styrene-acrylonitrile copolymer), weight-average particle diameter approx. 500 nm

a) Production of a seed latex

To produce a seed latex, 16 g of butyl acrylate and 0.4 g of tricyclodecenyl acrylate in 150 g of water with the addition of 1 g of the sodium salt of a Ci ₂ "Ci ₈ - araffinsulfonic acid, 0.3 g of potassium persulfate, 0.3 g of sodium hydrogen carbonate and 0.15 g Sodium pyrophosphate was heated with stirring to 60 ° C. 10 minutes after the start of the polymerization reaction, a mixture of 82 g of butyl acrylate and 1.6 g of tricyclodecenyl acrylate was added over the course of 3 hours, and the reaction was allowed to continue for one hour after the monomer addition had ended Latex had a solids content of 40% and a weight average Particle size dso of 76 nm. The particle size distribution was narrow (quotient Q = 0.29).

b) Preparation of the graft polymer

A mixture of 98 g of n-butyl acrylate and 2 g of dihydrodicyclopentadienyl acrylate and, separately, a solution of were added to a mixture of 3 g of the polybutyl acrylate seed latex, 100 g of water and 0.2 g of potassium persulfate in the course of 4 hours at 60 ° C. 1 g Na -C ₂ -Ci ₈ -paraffin sulfonate in 50 g of water. The polymerization was then continued for 3 hours. The weight-average particle diameter dso of the resulting latex was 430 nm with a narrow distribution of the particle size (Q = 0.1). The solids content was 40%.

150 g of this latex were mixed with 60 g of water, 0.03 g of potassium persulfate and 0.05 g of lauroyl peroxide, after which 20 g of styrene were initially applied to the latex particles over a period of 3 hours at 65 ° C. and then a mixture was added over a further 4 hours were grafted on from 15 g of styrene and 5 g of acrylonitrile. The polymer dispersion obtained was processed as such. The degree of grafting of the polymer was 40% and the particles had a weight-average diameter dso of 510 nm.

Production of a component B-2 (according to the invention)

Rubber-elastic graft polymer (core cross-linked polybutyl acrylate, shell styrene-acrylonitrile copolymer), weight-average particle diameter approx. 90 nm

150 g of the polybutyl acrylic seed latex, produced as below

Bl a) described, were mixed with 40 g of a mixture of styrene and acrylonitrile (weight ratio 75:25) and 60 g of water and with stirring after the addition of a further 0.03 g of potassium persulfate and 0.05 g of laroyl peroxide at 65 ° C. for 4 hours heated. The polymer dispersion obtained was processed as such. The degree of grafting of the graft copolymer was 40%, and the particles had a weight-average particle diameter dso of 90 nm.

Production of a component C-1 (according to the invention) rubber-elastic graft polymer (core crosslinked butyl acrylate, shell styrene-acrylonitrile copolymer) by micro-suspension polymerization, volume-average particle diameter approx. 3 μm

Products from Hoechst,

Frankfurt / M., DE, with the designation Mowiol® used. The first number after the brand name indicates the viscosity of one 4 wt. -% solution of the polyvinyl alcohol in water at 20 ° C in [mPa / s], measured according to DIN 53015; the second number indicates the degree of hydrolysis (degree of saponification) of the polyvinyl alcohol in mol%. 5 a) Manufacture of the core

A mixture was made in a container

10 1680.8 g of n-butyl acrylate

34.4 g dihydrodicyclopentadienyl acrylate 2956.2 g water 343.0 g a 10 wt. -% solution of the polyvinyl alcohol Mowiol® 8/88 in water 15 8.6 g dilauryl peroxide

submitted and with an immersed homogenizer of the type

Dispermat CV (VMA-Gelzmann), which at a speed of

7000 min ^-1 was operated for 20 min, an emulsion was prepared.

20 10% by weight of this emulsion were placed in a reactor flushed with nitrogen, the temperature of which was 75 ° C. and which was stirred with a blade stirrer (300 min ^-1 ). The remaining 90% by weight of the emulsion were added dropwise at the same temperature and stirrer speed within one hour. Another was left

Polymerize for another 25 hours.

To 4900.0 g of the mixture prepared

1971.0 g of water and 30 446.5 g of a 10 wt. -% solution of the polyvinyl alcohol as described above

given. Then a mixture of

35,837.2 g styrene and 279.1 g acrylonitrile

added dropwise at 75 ° C. and 300 min " ¹ stirrer speed, and polymerized for a further hour.

40

After cooling, light microscopic images were taken of the reactor contents. The volume-average particle size ds ₀ , determined by measuring and counting the graft particles cut at the equator, was 3 μm.

45 The polymer dispersion obtained was processed as such.

Production of a component C-2 (according to the invention) rubber-elastic graft polymer (core crosslinked butyl acrylate, shell styrene-acrylonitrile copolymer) by micro-suspension polymerization, volume-average particle diameter approx. 10 μm

There were

1230 g water

8.6 g NaHP0 ₄ ^• 12 H0 3.2 g NaH ₂ P0 • 12 H ₂ 0 1.6 g dilauroyl peroxide

100 g of a 10 wt. -% solution of the polyvinyl alcohol

Mowiol® 8/88 in water 600 g n-butyl acrylate and

9.0 g dihydrodicyclopentadienyl acrylate

added in the order given under nitrogen and stirred with a high-performance stirrer (dissolver stirrer, speed 3500 min ^" 1.5 cm toothed disk) for 40 min. At the same time, the mixture was gradually heated to 73 ° C. Thereby monomer droplets of average diameter of 10 μm, as determined microscopically on a sample.

This dispersion was transferred to another kettle and held there with moderate stirring at 87 ° C. for 2 hours, the core polymer (conversion about 95%) being formed.

The mixture was then mixed with a mixture with moderate stirring at 70 ° C over 10 minutes

280 g styrene

120 g acrylonitrile

0.5 g tert. Butyl perpivalate and

0.5 g 2-ethylhexyl thioglycolate

added, then kept at 70 ° C. for 2 hours and then heated to 85 ° C. within 2 hours.

After cooling, light microscopic images were taken of the reactor contents. The volume average particle size d ₅₀ , determined by measuring and counting the graft particles cut at the equator, was 10 μm. The polymer dispersion obtained was processed as such.

Production of polymer blends:

The polymer dispersions containing the polymers B1 and B-2 were coagulated by adding a magnesium sulfate solution and on an extruder type ZSK 30 from Werner and Pfleiderer with the styrene-acrylonitrile copolymer component A) to precursors VP1 and VP2 mixed.

Preproduct VPl contained 48% by weight of polymer B-1 (calculated as a solid) and 52% by weight of component A).

Preproduct VP2 contained 50% by weight of polymer B-2 (calculated as a solid) and 50% by weight of component A).

During the manufacture of the preliminary products VP1 and VP2, the dispersion water was removed along the extruder via degassing openings. The discharged polymer melt was granulated after cooling.

The preliminary products VP1 and VP2, respectively, were melted, if appropriate together with a further amount of component A), in a type ZSK 30 extruder. The polymer dispersions containing the polymers C-1 and C-2 were pumped into the polymer melt. The amounts of VPl, VP2, optionally A), and of dispersions of C-1 and C-2 were chosen so that the mixtures given in the table were formed.

The dispersion water was removed along the extruder via degassing openings and the melt discharged after cooling was granulated.

Manufacture and testing of molded parts:

The granules were sprayed at 220 ° C melting temperature and 60 ° C mold temperature into standard small bars (see DIN 53 453). Furthermore, round disks 60 mm in diameter and 2 mm in thickness were injection molded at a melting temperature of 260 ° C. and a mold temperature of 30 ° C.

The notched impact strength a _k was determined on the standard small bars according to DIN 53 453. The gloss measurement (light reflection) was determined on the circular disks in accordance with DIN 67 530 using a Gonio GPZ photometer from Carl Zeiss at an angle of 60 ° (reflection).

The table below summarizes the test results.

table

¹⁾ V for comparison ²⁾ Rubber share in the total molding compound [wt. -%]

Molding compositions from SAN matrix A) and a graft polymer B-2 according to the invention of small diameter (<300 nm, namely 90 nm) made of polybutyl acrylate core and SAN shell, but without the large-scale microsuspension polymer C), have an s> Very low impact strength, as comparative example IV shows.

If - not according to the invention - the graft polymer B-2 is replaced by one with a larger diameter B-1 (> 300 nm, namely 500 nm), the molding compositions do not have a matt surface (comparative examples 9V and 14V).

Molding compositions from SAN matrix A), the large-scale graft polymer B1 not according to the invention (diameter> 300 nm) and the large-scale microsuspension polymer C) according to the invention have a glossy surface (comparative example 10V to 13V and 15V to 16V), regardless of whether the Microsuspension polymers Cl (diameter 3 μm, 10V to 13V) or C-2 (diameter 10 μm, 15V to 16V) can also be used.

In contrast, molding compositions which contain both the small-part graft polymer B-2 according to the invention (diameter <300 nm) and the large-part microsuspension polymer C) also have high impact strength and matt surfaces.

This becomes particularly clear when comparing Examples 2 with 10V, 3 with 11V, 4 with 12V, and 5 with 13V. These pairs of examples differ only in the particle size of component B) with the same proportions of components A), B) and C). In each pair of examples, the gloss of the example according to the invention, with a comparable impact strength, is less than that of the example not according to the invention.

Claims

claims

1. Thermoplastic molding compositions containing

A) 30 to 98% by weight of a thermoplastic polymer, based on A)

al) 50 to 100% by weight of a styrene compound of the general formula

R ²

in which R ¹ and R ^{2 represent} hydrogen or Ci-Cβ-alkyl,

or

one (Ci-Cβ-alkyl) ester of acrylic acid or methacrylic acid,

or mixtures of the styrene compound and the

(Ci-Cβ-alkyl) esters of acrylic acid or methacrylic acid,

B) 1 to 69% by weight of a first particulate rubber-elastic polymer B) with a weight-average particle diameter d 50 of 300 nm or less,

C) 1 to 69% by weight of a second particulate, rubber-elastic polymer C) with a volume-average particle diameter dso of 700 nm to 100 μm

the polymer C) is obtainable after the microsuspension polymerization process i) dispersing the monomers corresponding to polymer C) in water using at least one protective colloid to form a dispersion of droplets with a volume-average particle diameter dso of 700 nm to 100 μm, and

ii) polymerization of the droplets using a radical polymerization initiator,

and

D) 0 to 80% by weight of one or more further polymers

2. Thermoplastic molding compositions according to claim 1), in which the first rubber-elastic polymer B) was prepared by the process of emulsion polymerization.

3. Thermoplastic molding compositions according to claims 1 and 2, in which the weight ratio of the first rubber-elastic

Polymer B) to second rubber-elastic polymer C) is in a range from 2:98 to 98: 2.

4. Thermoplastic molding compositions according to claims 1 to 3, in which the first rubber-elastic polymer B) and the second rubber-elastic polymer C) are each graft polymers P), based on P),

pl) 30 to 95% by weight of a rubber-elastic basic stage, based on pl),

pll) 50 to 100% by weight of a (-CC-alkyl) ester of acrylic acid,

pl2) 0 to 10% by weight of a polyfunctional, crosslinking monomer,

pl3) 0 to 40% by weight of one or more further monoethylenically unsaturated monomers,

or off, based on pl),

pll *) 50 to 100% by weight of a diene with conjugated double bonds, pl2 *) 0 to 50% by weight of one or more further monoethylenically unsaturated monomers,

p2) 5 to 70 wt. -% of a graft stage based on p2)

p21) 50 to 100% by weight of a styrene compound of the general formula

R ²

in which R ¹ and R ^{2 represent} hydrogen or Ci-Cβ-alkyl,

or

one (Ci-Cβ-alkyl) ester of acrylic acid or methacrylic acid,

or mixtures of the styrene compound and the (Ci-Cβ-alkyl) ester of acrylic acid or methacrylic acid,

p22) 0 to 40% by weight of acrylonitrile or methacrylonitrile or their mixtures and

p23) 0 to 40% by weight of one or more further monoethylenically unsaturated monomers.

5. Thermoplastic molding compositions according to claims 1 to 4, in which the second rubber-elastic polymer C) is obtainable by the microsuspension polymerization process

i) dispersing the monomers corresponding to basic stage pl) in water using at least one protective colloid to give a dispersion of droplets with a volume-average particle diameter dso of

700 nm to 100 μm,

ii) polymerization of the droplets by means of a radical polymerization initiator up to a conversion of more than 50%, based on the monomers, and iii) graft polymerization of the mixture obtained in stage ii) with the addition of the monomers corresponding to the graft stage p2).

6. A process for the preparation of a particulate rubber-elastic polymer C) according to claims 1 to 5 by polymerization in the aqueous phase, characterized in that

i) that the monomers corresponding to polymer C) are subjected to dispersion in water using at least one protective colloid until the monomer droplets have a volume-average particle diameter dso of 700 nm to 100 μm, and

ii) that the monomers are polymerized by means of a radical polymerization initiator.

7. A process for the preparation of a particulate rubber-elastic graft polymer P) according to claims 1 to 5, comprising a basic stage pl) and a graft stage p2), by polymerization in an aqueous phase, characterized in that

i) subjecting the monomers corresponding to basic stage pl) to dispersion in water using at least one protective colloid until the monomer droplets have a volume-average particle diameter dso of 700 nm to 100 μm,

ii) that the monomers of the basic stage are polymerized by means of a radical polymerization initiator up to a conversion of more than 50%, based on the monomers, and

iii) that the mixture obtained in stage ii) and containing the base stage pl) is graft-polymerized with the addition of the monomers corresponding to the graft stage p2).

8. A process for producing a thermoplastic molding composition according to claims 1 to 5, characterized in that components A), B), C) and D) are melted in an extruder or other mixing device at temperatures of 100 to 320 ° C mixed, and discharges.

9. Use of the thermoplastic molding compositions according to claims 1 to 5 for the production of moldings.

10. Moldings from the thermoplastic molding compositions according to claims 1 to 5.