DE19817993A1 - Improving puncture resistance of impact-modified styrene/acrylonitrile copolymers while imparting good antistatic properties - Google Patents

Abstract

The puncture resistance of impact-modified styrene and/or alpha -Me-styrene/acrylonitrile copolymers is improved, while also imparting good antistatic properties, by use of a triblock copolymer X-Y-X (X = ethylene oxide units forming on average 2-35 wt.% of the copolymer and Y = propylene oxide units of average mol. wt. 2000-4000). There is also an Independent claim for a molding composition comprising, by wt., (A) 20-94% hard copolymer of styrene and/or alpha -Me styrene with 10-50% acrylonitrile; (B) 5-70% graft copolymer of (1) 10-90% rubber-elastic, particulate substrate of Tg below 0 deg C and (2) 10-90% copolymer as per (A) as graft; (C) 0.1-10% triblock copolymer X-Y-X as above; and (D) 0-10% conventional additives and fillers.

Description

The invention relates to thermoplastic molding compositions with high puncture resistance stability and good antistatic behavior. The molding compounds are are impact-modified copolymers of styrene and / or α-methylstyrene with acrylonitrile.

Impact-modified styrene / acrylonitrile copolymers are used in one Variety of applications used. They are preferred for production of moldings used that have good mechanical properties should. It is often necessary to provide such molded articles with antistatic properties. The equipment is usually added by adding an antistatic the molding compounds. To ensure a sufficient range of use of the molding compounds To ensure it is desirable to use the molding compound for a wide range Adapt the area to the machining conditions.

From FR-B-1 239 902 polymer resins are known which are anti-electrostatic are equipped. Among other things, molding compounds containing polystyrene, Have polyacrylonitrile and polybutadiene units, with three-block copolyme Ren of the formula X-Y-X are equipped, where Y is a polypropylene means oxide block with a molecular weight of 1000 to 1800 and X each represent polyethylene oxide blocks, the proportion of polyethylene oxide Is 20 to 80%.  

EP-B 0 018 591 discloses styrene / acrylonitrile copolymers which do not Contain rubber component, with the aforementioned three-block copolymers with the formula X-Y-X. The equipment is used to make the interior tion of the molding compounds increased, which leads to an improvement in processing wide in injection molding leads. In the three-block copolymer, the molecular weight can of the block Y are 1200 to 3650, the proportion of ethylene oxide being units is 10 to 30% by weight.

From EP-A-0 125 801 it is known to polymer blends made of polycarbonate and Impact-resistant styrene / acrylonitrile copolymer to improve the Processing range with the aforementioned three-block copolymers of the formula Equip X-Y-X. The molecular weight of the polypropylene oxide blocks Y are 1200, 2250 or 3600, for example. The share of Ethylene oxide is 10 or 40% by weight.

The object of the present invention is to provide impact resistance equipped copolymers of styrene and / or α-methylstyrene with Acrylonitrile, which has increased puncture resistance while at the same time being good exhibit antistatic behavior.

According to the invention, the object is achieved by a molding composition composed of components A to C and optionally D,

• a: 20 to 94 wt .-% of a hard component of one or more Copolymers of styrene and / or α-methylstyrene with acrylonitrile, wherein the proportion of acrylonitrile is 10 to 50 wt .-%, as Kom component A,
• b: 5 to 70% by weight of at least one graft copolymer B.
  • b1: 10 to 90% by weight of at least one rubber-elastic particulate graft base with a glass transition temperature below 0 ° C. as component B1 and
  • b2: 10 to 90% by weight of at least one graft made from a copolymer of styrene and / or α-methylstyrene with acrylonitrile, the proportion of acrylonitrile being 10 to 50% by weight, as component B2,
• c: 0.1 to 10% by weight of at least one three-block copolymer of the formula XYX with a central block Y of propylene oxide units with an average molecular weight in the range from 2000 to 4000 and terminal blocks X of ethylene oxide units, the average proportion in the three-block copolymer of 2 to 35% by weight .-%, as component C,
  where the total weight of components A to C is 100% by weight,
• d: 0 to 10% by weight, based on the total weight of component A to C, other conventional auxiliaries and fillers as component D.

Suitable molding compounds with components A, B and D are for example in DE-A-29 01 576 and in particular from described earlier, not prepublished DE-A-197 28 629.

The proportion of the component in the molding compositions according to the invention is A preferably 40 to 84.9% by weight, particularly preferably 55 to 79.7 % By weight. The proportion of component B is preferably 15 to 50 % By weight, particularly preferably 20 to 40% by weight. The share of com Component C is preferably 0.1 to 5% by weight, particularly preferably 0.3  up to 2% by weight. The proportion of component D is preferably 0 to 5% by weight, particularly preferably 0 to 3% by weight.

The component of acrylonitrile in component A is preferably 10 to 50 % By weight, particularly preferably 15 to 40% by weight, in particular 18.5 to 36 % By weight.

In component B, the proportion of component B1 is preferably 20 to 80 wt .-%, particularly preferably 25 to 75 wt .-%, the proportion of Component B2 preferably 20 to 80% by weight, particularly preferably 25 up to 75% by weight. The proportion of acrylonitrile in component B2 is preferably 15 to 40% by weight, particularly preferably 15 to 35% by weight.

In component C, the average molecular weight of block Y is from Propylene oxide units preferably 2200 to 3800, particularly preferably 2300 to 3500, especially about 2300, about 2750 or about 3250, respectively ± 10%. The middle portion of the terminal blocks X from ethylene oxide units, based on component C, is preferably 3 to 28 % By weight, particularly preferably 8 to 24% by weight, in particular approximately 8 to 14 or about 18 to 24% by weight.

Component A

Component A preferably has a viscosity number VZ (determined according to DIN 53 726 at 25 ° C, 0.5 wt .-% in dimethylformamide) from 50 to 120 ml / g, particularly preferably 52 to 110 ml / g and in particular 55 to 105 ml / g. It is particularly preferably a styrene / acrylonitrile Copolymer. Such copolymers are obtained in a known manner by bulk, solution, suspension, precipitation or emulsion polymers tion, bulk and solution polymerization are preferred. details  These processes are described, for example, in the plastics manual, publisher R. Vieweg and G. Daumiller, Volume V "Polystyrene", Carl-Hanser-Verlag Mün Chen 1969, page 118 ff.

Component B

Component B is a graft copolymer with a rubber elastic particulate graft base with a glass transition temperature below 0 ° C. The graft base can be from all known suitable chews chukelastic polymers can be selected. It is preferably ABS (acrylonitrile / butadiene / styrene) -, ASA (acrylonitrile / styrene / alkyl acrylate) -, EPDM, siloxane or other rubbers.

Component B1 is preferably at least one (co) polymer

• b11: 60 to 100% by weight, preferably 70 to 100% by weight, of at least one conjugated diene, C _1-10 alkyl acrylate or mixtures thereof as component B11,
• b12: 0 to 30% by weight, preferably 0 to 25% by weight at least one monoethylenically unsaturated from component B11 took monomers as component B12 and
• b13: 0 to 10% by weight, preferably 0 to 6% by weight, of at least one crosslinking monomers as component B13.

Suitable conjugated dienes B11 include, in particular, butadiene, isoprene, chloroprene or mixtures thereof, and also the C _1-10 alkyl acrylates and mixtures listed below. Butadiene or isoprene or mixtures thereof, especially butadiene, or n-butyl acrylate are preferably used.

If necessary, component B12 may contain monomers which vary the mechanical and thermal properties of the core within a certain range. Examples of such monoethylenically unsaturated comonomers are styrene, substituted styrenes, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, dicarboxylic acids such as maleic acid and fumaric acid and their anhydrides such as maleic anhydrides such as dimethylaminoethylacrylate, diethylaminoethylaolonyl acrylate, vinyl acrylamide, vinyl acrylamide, vinyl acrylamide, vinyl acrylamide, vinyl acrylamide, vinyl vinylamine , Acryl amide, C _1-10 alkyl esters of acrylic acid such as methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, ethylhexyl acrylate, the corresponding C _{1- 10-} alkyl esters of methacrylic acid and hydroxyethyl acrylate, 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 acrylate, 2-phenoxyethyl acrylate acrylate and 2-phenoxyethyl acrylate and 2-phenoxyethyl acrylate e such as N-methyl, N-phenyl and N-cyclohexylmaleimide, unsaturated ethers such as vinyl methyl ether and mixtures thereof.

Styrene, α-methylstyrene, n-butyl acrylate and methyl methacrylate are preferred or mixtures thereof are used as component B12, in particular styrene and n-butyl acrylate or mixtures thereof, especially styrene. If a com component B12, but no component B13 is used, is Proportion of component B11 preferably 70 to 99.9, particularly preferably 90 to 99 wt .-% and the proportion of component B12 0.1 to 30, esp more preferably 1 to 10 wt .-%. Butadiene / styrene are particularly preferred. and n-butyl acrylate / styrene copolymers in the specified amount range.

Examples of crosslinking monomers of component B13 are divinylver bonds such as divinylbenzene, diallyl compounds such as diallyl maleate, allyl  esters of acrylic and methacrylic acid, dihydrodicyclopentadienyl acrylate (DCPA), divinyl esters of dicarboxylic acids such as succinic acid and Adipic acid, diallyl and divinyl ethers of bifunctional alcohols such as the Ethylene glycol and butane-1,4-diols.

The graft B2 is preferably a styrene / acrylonitrile copolymer.

Usually, the graft copolymers B by the process of Made emulsion polymerization. Usually you polymerize at a temperature of 20 to 100, preferably 30 to 80 ° C. Often usual emulsifiers are used, 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 metals are preferably used tall salts, especially the sodium or potassium salts of alkyl sulfonates or fatty acids with 10 to 18 carbon atoms.

As a rule, the emulsifiers are used in amounts of 0.5 to 5% by weight, in particular from 0.5 to 3% by weight, based on the production the graft base used monomers.

It is preferred to use as much water to prepare the dispersion, that the finished dispersion has a solids content of 20 to 50% by weight having. Usually at a water / monomer ratio of 2: 1 to 0.7: 1 worked.

All radical formers are suitable for starting the polymerization reaction disintegrate at the selected reaction temperature, both those which thermally decay alone, as well as those that do so in the presence of a Redox systems do. Preferred polymerization initiators are  Free radical formers, for example peroxides such as preferably peroxosulfates (approx Sodium or potassium persulfate) and azo compounds such as azo diisobutyroni tril into consideration. However, redox systems can also be used, especially those based on hydroperoxides such as cumene hydroperoxide.

As a rule, the polymerization initiators are used in an amount of 0.1 up to 1% by weight, based on the graft base monomers.

The radical formers and also the emulsifiers become the reaction mixture for example discontinuously as the total amount at the start of the reaction, or divided into several portions at the beginning and one at a time added or several later times, or continuously during added at a certain time interval. The continuous addition can also take place along a gradient z. B. ascending or descending, linear or exponential, or also stepwise (stair function).

Molecular weight regulators such as ethylhexylthioglycolate, n- or t-dodecyl mercaptan or other mercaptans, terpinols and dimeres Methylstyrene or others suitable for regulating the molecular weight Use connections. The molecular weight regulators are the Reaction batch added batchwise or continuously, as for the radical generator and emulsifier has been previously described.

To maintain a constant pH value, which is preferably 6 to 9, buffer substances such as Na ₂ HPO / NaH ₂ PO ₄ , sodium hydrogen carbonate or buffers based on citric acid / citrate can also be used. Regulators and buffer substances are used in the usual quantities, so that further details are not necessary.

In a special embodiment, the graft base can also be used by polymerization of the monomers B1 in the presence of a finely divided Produce latex (so-called "seed latex mode of operation" of the polymerization). This Latex is presented and can be made from rubber-elastic polymers Monomers, or from other monomers, as already mentioned were exist. Suitable seed latices consist, for example, of polybuta diene or polystyrene.

In another preferred embodiment, one can use the graft base Produce B1 in the so-called feed process. With this procedure a certain proportion of the monomers submitted and the polymerization started, after which the rest of the monomers ("feed fraction") B1 as Adds feed during the polymerization. The inflow parameters (shape of the Gradients, amount, duration, etc.) depend on the other polymerization conditions. The same applies to the addition of the Radical start or emulsifier made executions.

Graft polymers with several “soft” and "hard" shells.

The exact polymerization conditions, in particular the type, amount and dosage of the emulsifier and the other polymerization auxiliaries are preferably chosen so that the latex of the graft polymer B obtained has an average particle size, defined by the d ₅₀ value of the particle size distribution, of 80 to 800 nm 80 to 600 nm and particularly preferably 85 to 400 nm.

According to one embodiment of the invention, the reaction is tuned conditions so that the polymer particles are bimodal  Have particle size distribution, i.e. a size distribution with two more or less pronounced maxima.

The bimodal particle size distribution is preferably achieved by a (partial) agglomeration of the polymer particles. This can be done, for example, as follows: The monomers which form the core are polymerized up to a conversion of usually at least 90%, preferably greater than 95%, based on the monomers used. This turnover is usually reached after 4 to 20 hours. The rubber latex obtained has an average particle size d ₅₀ of at most 200 nm and a narrow particle size distribution (almost monodisperse system).

In the second stage, the rubber latex is agglomerated. This is usually done by adding a dispersion of an acrylic ester polymer. Dispersions of copolymers of (C ₁ -C ₄ -alkyl) esters of acrylic acid, preferably of ethyl acrylate, with monomers forming 0.1 to 10% by weight of polar polymers, such as acrylic acid, methacrylic acid, acrylamide or methacrylamide, N, are preferred -Methylol methacrylamide or N-vinyl pyrrolidone, used. A copolymer of 96% ethyl acrylate and 4% methacrylamide is particularly preferred. The agglomerating dispersion can optionally also contain several of the acrylic ester polymers mentioned.

The concentration of the acrylic ester polymers in the agglomeration dispersion used should generally be between 3 and 40% by weight lie. In the agglomeration, 0.2 to 20, preferably 1 to 5 Parts by weight of the agglomeration dispersion per 100 parts of the rubber latex, each calculated on solids. The agglomeration is through The agglomeration dispersion was added to the rubber. The Ge Speed of addition is usually not critical, in general  it takes about 1 to 30 minutes at a temperature between 20 and 90 ° C, preferably between 30 and 75 ° C.

In addition to using an acrylic polymer dispersion, the rubber latex also agglomerated by other agglomerating agents such as acetic anhydride become. Agglomeration by pressure or freezing (pressure freezer agglomeration) is possible. The methods mentioned are the Known specialist.

Under the conditions mentioned, only a part of the rubber particles agglomerated, so that a bimodal distribution arises. Thereby lie agglomeration generally more than 50, preferably between 75 and 95% of the particles (number distribution) in the non-agglomerated state in front. The partially agglomerated rubber latex obtained is relatively stable, so that it can be easily stored and transported without Coagulation occurs.

In order to obtain a bimodal particle size distribution of the graft polymer B. achieve, it is also possible to use two different graft polymers B 'and B '', which differ in their average particle size, separated from each other other in the usual way and the graft polymers B 'and B' ' to combine in the desired ratio.

The graft B2 can be produced under the same conditions how to make the graft base B1, the Aufla can produce ge B2 in one or more process steps. Example With a two-stage grafting, styrene or α-methylstyrene alone and then styrene and acrylonitrile in two on top of each other polymerize following steps. This two-stage grafting (initially Styrene, then styrene / acrylonitrile) is a preferred embodiment. Further  Details of the preparation of the graft polymers B are in the DE-A 12 60 135 and 31 49 358 and EP-A-0 735 063.

It is advantageous to graft polymerize onto the graft base B1 again in an aqueous emulsion. It can be in the same system how to polymerize the graft base, where further emulsifier and initiator can be added. These must go with the emulsifiers used to prepare the graft base B1 or Initiators may not be identical. So it can e.g. B. be useful as Ini tiator for the production of the graft base B1 a persulfate apply, but a redox initiator for the polymerization of the graft B2 stem. Otherwise, the choice of emulsifier, initiator and Polymerization auxiliaries that are used in the preparation of the graft base B1 Said. The monomer mixture to be grafted on can be the reaction mixture mix at once, batchwise in several stages or preferably con be added continuously during the polymerization.

So much for the grafting of the graft base B1 not grafted polymers from the monomers B2 arise, the amounts that are usually are below 10% by weight of B2, assigned to the mass of component B.

Component C

The three-block copolymers of the formula XYX used according to the invention can be prepared in a manner known per se (N. Schönfeldt, surface-active ethylene oxide adducts, Wisserschaffliche Verlagsgesellschaft mbH Stuttgart, 1976, page 53 ff) by polymerization, initially producing a medium-sized polypropylene oxide block Y, a block of ethylene oxide units is attached to each end. The molecular weights given above are generally the average molecular weights (number average M _n , for example determined from the OH number according to DIN 53 240).

Three-block copolymers and their preparation are also preferred in EP-A-0 125 801 and EP-A-0 018 591.

Component D

Other conventional auxiliaries and fillers can be used as component D. become. Such substances are, for example, lubricants or mold release agents, Waxes, pigments, dyes, flame retardants, antioxidants, stabilizers sensors against exposure to light, fibrous and powdery filling or Ver tonic or antistatic, as well as other additives, or their Mixtures.

Suitable lubricants and mold release agents are e.g. B. stearic acids, stearyl alcohol hol, 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 soot, as well as the entire class of organic pigments.

Dyes are to be understood as all dyes that are transparent, semi-transparent or non-transparent coloring of polymers ver can be used, especially those used for coloring styrene copolymers are suitable. Such dyes are the expert knows.

As flame retardants such. B. the halogen known to those skilled in the art containing or phosphorus-containing compounds, magnesium hydroxide, and  other common compounds or mixtures thereof who used the. Red phosphorus is also suitable.

Suitable antioxidants are, in particular, sterically hindered mononuclear ones or polynuclear phenolic antioxidants, in different ways can be substituted and also bridged by substituents. For this include not only monomers but also oligomeric compounds consisting of several phenolic base bodies can be constructed. Hydrochi also come none and hydroquinone analogs and substituted compounds into consideration, also antioxidants based on tocopherols and their derivatives. Mixtures of different antioxidants can also be used. In principle, all commercially available or suitable for styrene copolymers Connections are used, such as Topanol® or Irganox.

Together with the phenolic antioxidants mentioned above as examples So-called costabilizers can also be used, in particular phosphorus or sulfur containing costabilizers. Such P- or S-containing Costabilizers are known to the person skilled in the art and are commercially available.

Suitable light stabilizers are e.g. B. different sub substituted resorcinols, salicylates, benzotriazoles, benzophenones, HALS (Hinde red amine light stabilizers), as they are e.g. B. commercially available as Tinuvin® are.

Coals are examples of fibrous or powdered fillers fabric or glass fibers in the form of glass fabrics, glass mats or glass egg denrovings, cut glass, glass balls and wollastonite, especially preferably glass fibers. When using glass fibers, these can be used better compatibility with the blend components with a size and be equipped with an adhesion promoter. The incorporation of the glass fibers can  both in the form of short glass fibers and in the form of endless strands (Rovings).

Carbon black, amorphous silica and magne are suitable as particulate fillers sium carbonate (chalk), powdered quartz, mica, mica, bentonite, valley cum, feldspar or in particular calcium silicates such as wollastonite and kaolin.

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

Production of molding compounds

The molding compositions are preferably produced by separate means Manufacture of the individual components A to C and optionally D and subsequent mixing of the components.

Suitable processes for producing the molding compositions are, for example, in EP-A-0 135 801, EP-B-0 018 591 and in particular DE-A-197 28 628 described.

The molding compositions according to the invention can be used to produce molded articles pern, fibers or foils are used. Such a method for Her position of moldings, fibers or foils are given in the Publications listed.

The invention is explained in more detail below with the aid of examples.

Examples 1. Preparation of the graft polymer B 1.1. Preparation of the graft base B1

43 120 g of the monomer mixture shown in Table 1 are in the presence of 432 g of tert-dodecyl mercaptan (TDM), 311 g of potassium salt of C ₁₂ -C ₂₀ fatty acids, 82 g of potassium persulfate, 147 g of sodium hydrogen carbonate and 58400 g of water at 65 ° C polymerized to a polybutadiene latex. In detail, the procedure was as in EP-A-0 062 901, Example 1, page 9, line 20-S. 10, line 6. The conversion was 95% or more. The average particle size d _{50 of} the latex was 80 to 120 nm.

35,000 g of the latex obtained were added to agglomerate the latex 65 ° C by adding 2700 g of a dispersion (solids content 10 % By weight) of 96% by weight of ethyl acrylate and 4% by weight of methacrylic acid amide agglomerated (partial agglomeration).

When using an n-butyl acrylate polymer as the graft base B1 as in EP-A-0 735 063, examples V1, V2, 14 V and 15 V.

1.2. Production of the graft B2

9000 g of water, 130 g of potassium salt of C ₁₂ -C ₂₀ fatty acids and 17 g of potassium peroxodisulfate were added to the agglomerated latex. The monomer mixtures given in Table 2 were then added at 75 ° C. over the course of 4 hours with stirring. The turnover, based on the graft monomers, was almost quantitative.

The graft polymer dispersion obtained with bimodal particle size distribution had an average particle size d ₅₀ of 150 to 350 nm and ad ₉₀ value of 400 to 600 nm. A first maximum of the particle size distribution was in the range 50 to 150 nm, a second maximum in the range 200 to 600 nm.

The dispersion obtained was treated with an aqueous dispersion of an anti oxidans added and then by adding a magnesium sulfate solution coagulates. The coagulated rubber was stripped from the water of dispersion centrifuged and washed with water. A rubber with approx. 30% by weight of adhering or enclosed residual water.

Table 1

Graft base B1

K2 was obtained according to DE-A-31 49 358.

Table 2

Graft pad B2 and finished graft polymer B

2. Preparation of the polymers A

The thermoplastic polymers A were by the method of continuous solution polymerization, as it is done in art Stoff-Handbuch, ed. R. Vieweg and G. Daumiller, Volume V "Polystyrol", Carl-Hanser-Verlag Munich 1969, pp. 122-124, is described. Table 3 summarizes the compositions and properties.

Table 3

Components

3. Production of the blends from components A and B Mixing after drying the graft rubber B

The graft rubber B containing residual water was dried with warm air in a vacuum and mixed intimately with the further component A in an extruder, type ZSK 30 from Werner and Pfleiderer, at 25 ° C. and 250 mm ⁻¹ at a throughput of 10 kg / h. The Formmas se was extruded and the molten polymer mixture was subjected to rapid cooling by being introduced into a 30 ° C water bath. The solidified molding compound was granulated.

4. Measurements taken

Swelling index of the graft base B1: A film was produced from the aqueous dispersion of the graft base by evaporating the water. 0.2 g of this film was mixed with 50 g of toluene. After 24 hours the toluene was aspirated from the swollen sample and the sample weighed out. After drying the sample in vacuo at 110 ° C. for 16 hours, it was weighed out again. The following were calculated:

Particle sizes of the rubber latex

The indication of the average particle size d is that Weight average particle size, as determined by means of an analytical ultrazen trifuge according to the method of W. Scholtan and H. Lange, Kol loid-Z. and Z.-Polymer 250 (1972) pages 782 to 796. The ultracentrifuge measurement provides the integral mass distribution of the part diameter of a sample. From this it can be seen how much Ge weight percent of the particles have a diameter equal to or smaller than one certain size.

The d ₁₀ value indicates the particle diameter in which 10% by weight of all particles have a smaller and 90% by weight a larger diameter. Conversely, for the d ₉₀ value it applies that 90% by weight of all particles have a smaller and 10% by weight a larger diameter than the diameter which corresponds to the d ₉₀ value. The weight-average particle diameter d ₅₀ or volume-average particle diameter D ₅₀ indicates that particle diameter in which 50% by weight or% by volume of all particles have a larger and 50% by weight or% by volume a smaller particle diameter. d ₁₀ , d ₅₀ and d ₉₀ value characterize the width Q of the particle size distribution, where Q = (d ₉₀ -d ₁₀ ) / d ₅₀ . The smaller Q is, the narrower the distribution.

Viscosity number VZ: it was determined according to DIN 53 726 on a 0.5 % by weight solution of the polymer in dimethylformamide.

For the determination of the following mechanical and antistatic values Test specimens were made from the granules of the molding compositions by injection molding manufactured, namely standard small rods (see DIN 53 453), shoulder rods, Round discs with a diameter of 60 mm and a thickness of 2 mm or rectangle discs of 2 mm thickness. The melt temperature was 25 ° C. in each case and the mold temperature in each case 60 ° C, unless otherwise stated.

Vicat: The heat resistance according to Vicat was determined on pressed platelets ISO 306 / B with a load of 50 N and a heating rate of 50 K / h certainly.

a _D : The penetration work a _D was determined according to ISO 6603-2 on round disks or rectangular disks 40 × 40 mm by the plastic test at 23 ° C., the test specimens being produced at a melting temperature of 250.

Antistatic behavior

• 1. Dust chamber test: The dust becomes in a dust chamber for 10 sec whirled up. Coarse dirt is blown off and the Dust flower formation assessed visually.
• 2. on round discs (60 mm diameter, 2 mm thickness) after the corona Method (based on DIN VDE 0303 T.3). E (15) is available Residual charge after 15 minutes as a measure of the effectiveness of the antistatic cum.

Example V1 (comparison)

A mixture of 66% by weight of component Aa and 34% by weight of component Ba was extruded at 250 ° C (ZSK 30, Werner & Pfleiderer), the heat Dimensional stability was determined and the antistatic behavior in the Dust chamber checked. The results are shown in Table 4.

Examples V2 to V8, 9, 10

A mixture of 66% by weight of component Aa and 34% by weight of component Ba was extruded at 250 ° C with the antistatic agents listed in Table 4 (ZSK 30, Werner & Pfleiderer), the heat resistance was determined and antistatic behavior in the dust chamber checked. The results are listed in Table 4.  

Example V11 (comparison)

A mixture of 71 wt .-% component Ab and 29 wt .-% component Ba was extruded at 250 ° C (ZSK 30, Werner & Pfleiderer), the heat Dimensional stability was determined and antistatic behavior in the corona Test checked. The puncture behavior was also tested. The he Results are shown in Table 5.

Examples V12, 13 to 15

A mixture of 71 wt .-% component Ab and 29 wt .-% component Ba was extruded at 250 ° C with the antistatic agents listed in Table 5 (ZSK 30, Werner & Pfleiderer), the heat resistance was determined and antistatic behavior tested in the Corona test. Besides, that was Puncture behavior tested. The results are shown in Table 5.

As can be seen from the examples, neither are ethylene oxide nor Propylene oxide homopolymers effective. Only EO / PO three-block copolymers with a PO block from 2000 to 4000 and an EO content below 30% by weight are effective as an antistatic and mechanics improver.

Examples V16, 17, 18

A mixture of 71 wt .-% Ac and 29 wt .-% Bc was at 250 ° C with extruded the antistatic shown in Table 6, and the antistatic Behavior was determined in the dust chamber test. In addition, the through impact behavior tested.  

Claims (9)

1. molding composition from components A to C and optionally D,

• a: 20 to 94% by weight of a hard component composed of one or more copolymers of styrene and / or α-methylstyrene with acrylonitrile, the proportion of acrylonitrile being 10 to 50% by weight, as component A,
• b: 5 to 70% by weight of at least one graft copolymer B.
  • b1: 10 to 90% by weight of at least one rubber-elastic particulate graft base with a glass transition temperature below 0 ° C. as component B1 and
  • b2: 10 to 90% by weight of at least one graft made from a copolymer of styrene and / or α-methylstyrene with acrylonitrile, the proportion of acrylonitrile being 10 to 50% by weight, as component B2,
• c: 0.1 to 10% by weight of at least one triblock copolymer of the formula XYX with a central block Y of propylene oxide units with an average molecular weight in the range from 2000 to 4000 and terminal blocks X of ethylene oxide units, the average proportion of which in the triblock copolymer 2 to Is 35% by weight, as component C,
  where the total weight of components A to C is 100% by weight,
• d: 0 to 10% by weight, based on the total weight of components A to C, of other customary auxiliaries and fillers as components D.

2. Molding composition according to claim 1, characterized in that the com component A is a styrene / acrylonitrile copolymer. 3. Molding composition according to claim 2, characterized in that the proportion of acrylonitrile in component A is 10 to 50% by weight. 4. Molding composition according to one of claims 1 to 3, characterized in that component B1 is at least one (co) polymer

• b11: 60 to 100% by weight of at least one conjugated diene, C _1-10 alkyl acrylate or mixtures thereof as component B11,
• b12: 0 to 30% by weight of at least one monoethylenically unsaturated monomer different from component B11 as component B12 and
• b13: 0 to 10% by weight of at least one crosslinking monomer as component B13.

5. Molding composition according to one of claims 1 to 4, characterized in that in component C the average molecular weight of block Y 2200 to 3400 and the average proportion of Blocks X in the three-block copo lymer is 5 to 25 wt .-%.   6. A method for producing a molding composition according to one of claims 1 to 5 by separate production of the individual components A to C and optionally D and subsequent mixing of the components ten. 7. Use of molding compositions according to one of claims 1 to 5 for Manufacture of moldings, fibers or foils. 8. Moldings, fibers or films from a molding composition according to one of the Claims 1 to 5. 9. Use of three-block copolymers of the formula X-Y-X with a middle block Y of propylene oxide units with a middle Molecular weight in the range from 2000 to 4000 and terminal Blocks X from ethylene oxide units, the middle part of which is in the tripod copolymer is 2 to 28 wt .-%, to increase the puncture resistance speed of impact-modified copolymers of styrene and / or α-methylstyrene with acrylonitrile with good antistatic behavior ten.