WO1997047672A1

WO1997047672A1 - Block copolymers and thermoplastic mounlding compounds containing them

Info

Publication number: WO1997047672A1
Application number: PCT/EP1997/002818
Authority: WO
Inventors: Konrad Knoll; Wolfgang Loth; Hermann Gausepohl
Original assignee: Basf Aktiengesellschaft
Priority date: 1996-06-12
Filing date: 1997-05-30
Publication date: 1997-12-18
Also published as: DE19623415A1; EP0904308A1

Abstract

Block copolymers with blocks A and B of the general structure (A - B)n, A - B - A, B - A - B, X [(A - B)n]m, X [( B - A)n]m, X [(A - B - A)n]m or X [(B - A - B)n]m in which A is a diene-based block and B is a block of copolymers from monomers of the general formulae (I) and (II), where R1 = H or an alkyl radical with 1-22 C atoms, R2 = H or an alkyl radical with 1-22 C atoms, R3 = H or an alkyl radical with 1-4 C atoms, a = 0, 1, 2, 3, 4 or 5, b = 0, 1, 2, 3, 4 or 5, X is the radical of an m-functional coupling agent, n is a whole number in the range from 1 to 5 and m is a whole number in the range from 2 to 20.

Description

Block copolymers and thermoplastic molding compositions containing them

description

The present invention relates to block copolymers with blocks A and B of the following general structure

(A - B) _n

A - B - A

B - A - B

X [(A - B) _n ] _m , X [(B - A) _n ] _m , X [{A - B - A) _n ] _m or

X [(B - A - B) _n ] _m

in which

A for a block based on service,

B for a block of copolymers of monomers of the general formulas I and II,

With

Ri = H or alkyl radical with 1-22 C atoms R ₂ = H or alkyl radical with 1-22 C atoms R ₃ = H or alkyl radical with 1-4 C atoms a = 0, 1, 2, 3, 4 or 5 b = 0, 1, 2, 3, 4 or 5

X for the rest of an m-functional coupling agent n for an integer in the range from 1 to 5 and m for an integer in the range from 2 to 20

stand. The invention further relates to mixtures of the block copolymers according to the invention with copolymers of monomers of the formulas I and II and their use.

Rubber-modified styrene polymers have been known for a long time and are produced industrially on a large scale. They have good toughness and flowability, but have the disadvantage that softening points above 98 ° C. are difficult to achieve. Therefore, attempts have already been made to lower the glass transition temperature by using α or nucleus-substituted compounds of the

Styrols to raise. However, the disadvantage of this procedure is that α-substituted polystyrenes such as e.g. Depolymerize poly-α-methylstyrene very easily and core-substituted polystyrenes cause only a slight increase in the softening point and are also very expensive.

Another method is to copolymerize styrene with 1, 1-diphenylethylene as described by H. Yuki and J. Hotta et al. describe (Bulletin Chem. Soc. Jap., Vol. 40, p. 2659 (1967)). However, the process described there gives chemically inconsistent products which lead to poor mechanics. Because of the incomplete conversion and the impossibility of removing the 1,1-diphenylethylene (boiling point: 277 ° C.) with the usual degassing methods for polystyrene, products with a high residual monomer content are also obtained which cannot be used commercially. In addition, the products are not impact-modified and are therefore unusable for most applications.

The object of the present invention was therefore to develop a product with increased softening point and low residual monomer content while maintaining the toughness and thermal resistance of impact polystyrene.

This object was achieved according to the invention by block copolymers according to claim 1.

Preferred block copolymers according to the invention can be found in the subclaims and the description below.

According to the present invention, block copolymers with blocks A and B of the general structures (AB) _n , ABA, BAB, X [(AB) _n ] _m , X [(BA) _n ] _m , X (ABA) _m and X (BAB ) _m available, where A for a block based on dienes and B for a block of a copolymer of monomers of the general formula I and II, B for a block of polymers of the general formula II, X for the rest of a m-functional coupling tels, n is an integer in the range from 1 to 5 and m is an integer in the range from 2 to 20.

In principle, all dienes are suitable as diene components for block A, but those with conjugated double bonds such as butadiene, isoprene, dimethylbutadiene and phenylbutadiene are preferred.

The molecular weights (weight average values M _w ) of block A of the block copolymers according to the invention are generally in the range from 10,000 to 500,000, preferably from 50,000 to 350,000 and in particular from 70,000 to 250,000.

The copolymer block B is built up from monomers of the formula I and II.

The monomers of the general formula I are 1, 1-diphenylethylene and its derivatives which are optionally substituted on the aromatic rings by alkyl groups having up to 22 C atoms. Preferred alkyl groups as substituents are alkyl groups with 1 to 4 carbon atoms, such as methyl, ethyl, i- and n-propyl and n-, i- or tert. Butyl, to name a few. However, the unsubstituted 1,1-diphenylethylene is particularly preferably used itself.

The monomers of the general formula II are styrene and its derivatives substituted in the α-position or on the aromatic ring with alkyl groups having 1 to 4 carbon atoms. Preferred alkyl groups are those mentioned above for monomers of formal I as preferred; unsubstituted styrene itself is particularly preferred.

The molar ratio of the units derived from monomers I to units derived from monomers II is generally in the range from 1: 1 to 1:25, preferably from 1: 1.05 to 1:15 and particularly preferably in the range of

1: 1.1 to 1: 10. Since the monomers of the formula I generally do not polymerize on their own, products with molar ratios of more than 1: 1 are not easily accessible.

The copolymer block B is preferably constructed statistically from in each case one or more monomers of the structural formula I and in each case one or more monomers of the structural formula II. A copolymer of styrene and 1,1-diphenylethylene is particularly preferred. In order to ensure compatibility of the copolymer block B with the hard matrix, the statistical structure of the block B with that of the hard matrix is similar, particularly be preferred. The molecular weight M _w of block B is generally 20,000 to 500,000, but preferably 50,000 to 300,000.

The symbol "X" means the rest of an m-functional coupling means. The coupling center X is formed by the reaction of the living anionic chain ends with an at least bifunctional coupling agent. Examples of such compounds are found in U.S. Patents 3,985,830, 3,280,084, 3,637,554 and 4,091,053.

The ratio of blocks A and B is generally in the range from 90:10 to 20:80. A: B ratios of 90:15 to 65:35 are preferred for producing the so-called cell structure of the disperse phase and from 60:40 to 45:55 for producing a capsule particle morphology. The relationships between the morphology of the block rubber and the morphology of the disperse phase in the impact-resistant polystyrene are described in detail (see, for example, A. Echte, Advances in Chem. Ser. 222 (1989, 15)). The block copolymers according to the invention can be prepared by customary methods of anionic chemistry, as described, for example, by M. Morton. (M. Morton> Anionic Polymerization: Pnnciples and Practice <Academic Press, New York 1983).

In order to obtain a chemically uniform copolymer block B, however, it is advantageous to produce the block rubber continuously or in the feed process; This will be described in detail later in the production of component B of the thermoplastic molding compositions according to the invention.

In the block copolymers according to the invention which contain units which are derived from an m-functional coupling agent X, X reacts with the living anionic chain ends after the polymerization, as a result of which the structures according to claim 1 are formed.

Examples of suitable coupling agents are found in US 3,985,830, 3,280,084, 3,637,554 and 4,091,053. Epoxidized glycerides such as epoxidized linseed oil or soybean oil may be mentioned here only by way of example; divinylbenzene is also suitable. If the living anionic end is on the side of the B block, then it is preferably coupled with compounds which contain epoxy and / or ester groups; however, if the A block forms the active end, divinylbenzene is preferably used for the coupling. The block transitions can be both sharply separated and "smeared".

A "smeared" transition means a chain piece of the molecule in which the monomers of block A are randomly distributed with the monomers of block B. The desired molecular weight of the blocks is set via the ratio of initiator to monomer.

To improve the weather and thermal oxidation resistance of the block copolymers according to the invention, the diene blocks can be partially or completely hydrogenated. Methods for this are known and in the literature, e.g. EP 471 415, US 4,656,230 and US 4,629,767.

According to a further embodiment of the present invention, thermoplastic molding compositions are made available which contain 1 to 99, preferably 3 to 70 and in particular 4 to 40% by weight of a block copolymer according to the invention and 1 to 99, preferably 30 to 97 and in particular 65 to Containing 96% by weight, based on the polymer content, of copolymers of the monomers of the formulas I and Ha (as described hereinabove), the polymerization of the latter component taking place in the presence of the block copolymers. With regard to the description of the monomers of the formulas I and II, reference is made to the description of block B of the block copolymers according to the invention in order to avoid repetitions.

Particularly preferred copolymers as component A are described in DE-A 44 20 917, to which reference is made here.

To produce the thermoplastic molding compositions according to the invention, the block copolymers according to the invention are preferably dissolved in a monomer mixture of the structural formulas I and II and, if appropriate, an inert solvent, and this solution is preferably polymerized using organometallic initiators. "Inert solvent" is understood to mean a solvent which does not react with the organometallic initiator.

Both aliphatic and aromatic hydrocarbons can be used. Suitable solvents are, for example, cyclohexane, methylcyclohexane, benzene, toluene, ethylbenzene or xylene.

To achieve higher polymerization rates, small amounts of polar, aprotic solvents can be added. Diethyl ether, diisopropyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether or, in particular, tetrahydrofuran are suitable, for example. The polar cosolvent is added to the non-polar solvent in a small amount of approx.

0.5 - 5 vol.% Added. THF is particularly preferred in an amount of 0.1-0.3% by volume.

The anionic polymerization is initiated using organometallic compounds. Compounds of alkali metals, especially lithium, are preferred. Examples of initiators are methyl lithium, ethyl lithium, propyllithium, n-butyllithium, sec. Butyllithium and tert. Butyllithium. The organometallic compound is added as a solution in a chemically different (inert) hydrocarbon. The dosage depends on the desired molecular weight of the polymer, but is generally in the range from 0.002 to 5 mol%, if it is based on the monomers.

The polymerization temperature can be between 0 ° and 130 ° C. Temperatures of 50 ° -90 ° C. are preferred. Generally, under isothermal conditions, i.e. polymerized while keeping the polymerization temperature constant.

The polymerization of the monomers mentioned in the presence of

Block copolymers can be carried out continuously in one as well as in several process stages. To achieve better rubber utilization, ie to increase the soft phase portion, it is advisable to carry out the polymerization in at least two process stages, the monomer mixture being divided according to the conversion desired in the individual process stages and metered into each stage. A detailed description of a possible method of this type is described in DE 42 35 977. A further possibility of producing the desired impact-resistant products is first to produce the block rubber in a one-pot process and then to complete the polymerization with renewed initiation and further feeding in of the monomer mixture of the structural formulas I and II. The process is described in DE 42 35 978.

In order to guarantee a complete conversion of the monomers with the structural formula I, it is expedient to polymerize them in completely in the last process stage with a small additional amount of styrene or its derivatives.

After the polymerization, the living chain ends are generally covered with a proton-active substance, e.g. Alcohols or acids such as carbonic acid or formic acid or deactivated with water. The solution can then be degassed by customary methods, if appropriate using stripping agents such as water or nitrogen, and - if desired - provided with auxiliary agents such as lubricants, antistatic agents, antioxidants, etc.

The crosslinking of the rubber in the disperse particles has an influence on the mechanical properties of the polymer. It can be influenced either via the degassing temperature and / or by adding peroxides after the polymerization.

The reaction times are generally in the range from 0.1 to 24, preferably from 0.5 to 12 and in particular from 1 to 10 hours.

As component a) it is also possible to use block copolymers with blocks a _x and a _{2 of} the general structures (aι-a2) _n , al-a2- _a l, a2- _a l-a2,

X [(aι-a ₂ ) _n ] _m . X [(a ₂ -aι) _n] _m, X _(aι-a2 -aι) _m X and (a ₂ -a! -A ₂₎ _m Availability checked to made ^¬ supply, wherein A represents a block of a copolymer of Mo ¬ nomers of the general formulas I and II, B for a block of polymers of the general formula II, X for the remainder of an m-functional coupling agent, n for an integer in the range from 1 to 5 and m for an integer in the range of 2 to 20 are available.

After the polymerization, the coupling agent X reacts with the living anionic chain ends, as a result of which the structures described above are formed. Examples of suitable coupling agents can be found in US Pat. Nos. 3,985,830, 3,280,084, 3,637,554 and 4,091,053. Epoxidized glycerides such as epoxidized linseed oil or soybean oil may be mentioned here only by way of example; divinylbenzene is also suitable. If the living anionic end is on the side of the B block, then it is preferably coupled with compounds which contain epoxy and / or ester groups; forms but the A block is the active end, divinylbenzene is preferably used for coupling.

The block transitions can be sharply separated or "smeared".

A "smeared" transition is understood as a chain piece of the molecule in which the monomers of block A are randomly distributed with the monomers of block B. The desired molecular weight of the blocks is set via the ratio of initiator to monomer.

The reaction times are generally in the range from 0.1 to 24, preferably from 0.5 to 12 and particularly preferably from 1 to 15-10 hours.

As component C), the thermoplastic molding compositions according to the invention can contain 0 to 3000, preferably 0 to 2000 and particularly preferably 100 to 1000 ppm of monomers of the formula I. These are preferably monomers of the same formula as the monomers incorporated into component A) during the polymerization.

As component D), the thermoplastic molding compositions according to the invention can contain 0 to 500, preferably 0 to 200 and in particular 20 to 100 ppm of monomers of the formula II. These are preferably monomers of the same chemical formula as used in the production of component A) were used.

30 The amounts of components C) and D) relate to the weight of component A in the thermoplastic molding compositions.

As component E) the thermoplastic molding compositions according to the invention can be 0 to 90, preferably up to 60 and in particular up to

35 to 30% by weight, based on the total weight of the molding composition, of further components. Basically, there is no particular restriction with regard to the structure of these further polymeric components; however, preference is given to polymers which have at least a certain degree of compatibility with the component

40 A), otherwise the mechanical properties are usually unsatisfactory. Preferred polymers are styrene polymers such as impact-resistant or crystal-clear polystyrene or else polyphenylene ether polymers, optionally in a mixture with styrene polymers.

45 Furthermore, the thermoplastic molding compositions according to the invention can contain up to 50% by weight, based on the total weight of the thermoplastic molding composition, of further additives and processing aids as component F). Such additives are known to the person skilled in the art and are described in the literature, so that detailed information is unnecessary here. Examples include fibrous and particulate fillers, stabilizers against heat and UV light, mold release agents and lubricants. Pigmentation of the molding compositions according to the invention is of course also possible.

Flame-proof products with a high softening point can be produced particularly advantageously with the molding compositions according to the invention. For this purpose, the molding compositions are treated with halogen or / and phosphorus or phosphorus-nitrogen-containing flame retardants by customary processes, e.g. by extrusion or calendering, be intimately mixed.

Examples

Purification of 1,1-diphenylethylene (DPE)

Crude DPE (Aldrich or production by reacting phenylmagnesium bromide with acetophenone, acetylation with acetic anhydride and thermal elimination of acetic acid) is passed through a column with at least 50 theoretical plates (rotating belt column; for larger quantities, column with Sulzer packings) distilled to 99.8% purity. The mostly pale yellow distillate is filtered through a 20 cm Alox column (Woelm alumma for chromatography, anhydrous), titrated with 1.5 N sec-butyllithium until a strong red color and distilled in vacuo (1 mbar). The product thus obtained is completely colorless and can be used directly in the anionic polymerization.

Purification of the monomers and solvents

The cyclohexane (H) used as solvent was dried over anhydrous aluminum oxide and titrated with the adduct of sec-butyllithium and 1,1-diphenylethylene until it turned yellow. The butadiene (Bu) was derived from triisobutyl aluminum, the

1, 1-Dιphenylethylen (DPE) from sec-butyllithium (s-BuLi) distilled off. A 0.5 molar s-BuLi solution in cyclohexane was used as the initiator. Styrene (S) was dried over alumina just before use. All polymerizations were carried out under purified nitrogen with rigorous exclusion of air and moisture.

In the following examples, Bu stands for 1,3-butadiene, S for styrene and DPE for 1,1-diphenylethylene. Furthermore, the ratio information relates to the weight.

example 1

Preparation of a Bu-S / DPE block copolymer (Bu: S / DPE = 60:40; S: DPE = 2: 1)

5 l of cyclohexane, 1.6 kg of styrene and 0.8 kg of DPE were placed in a 55 l stirred reactor equipped with a cross-bar stirrer and at 60 ° C. with 1 molar s-butyllithium solution until the red color began titrated. After starting the reaction with 75 ml of the 1 m BuLi solution, the temperature of the reaction mixture was adjusted to 70 ° C. via jacket cooling and, after the reaction had subsided, a further 1.5 kg of styrene and 0.8 kg of DPE were simultaneously added. After 30 minutes, two 50 g portions of styrene were added to the black-red solution within 10 minutes until the orange-red color typical of polystyrene lithium persisted. It was diluted with 23 l of cyclohexane and 7.2 kg of butadiene were added with cooling such that 80 ° C. was not exceeded. After the reaction had subsided, it was neutralized with 10 ml of isopropanol and acidified with CO ₂ / water. The colorless solution was freed from the solvent in a degassing extruder and granulated.

GPC: Mn = 155,000 g / mol; M _w = 165,000 g / mol (mixed calibration for PS and PBu 40:60).

Example 2

Preparation of an S / DPE-Bu-S / DPE block copolymer (Bu: S / DPE = 65:35; S: DPE = 1.5: 1).

2.52 kg of styrene, 1.68 kg of DPE and 7.8 kg of butadiene were polymerized analogously to Example 1a, starting with 150 ml of 1 m BuLi solution. Instead of isopropanol, 5.55 g of ethyl formate in 100 ml of cyclohexane were metered in over the course of 5 minutes and the procedure was then continued as in Example 1a.

GPC: 1st peak (10% fraction): M (peak maximum) = 79,000 g / mol; 2nd peak (90% proportion): M (peak maximum) = 160,000 g / mol. Example 3

15 parts of the block copolymer prepared according to Example 1 were dissolved in 45 parts of ethylbenzene.

A cascade of 2 boilers (Ri, R ₂ ) and 2 tower reactors (Ti, T ₂ ) was used (cf. DE 17 70 392). The individual reactors had a volume of 1 and 2 1 (boiler) and 4 1 each (tower reactors).

The solution of the block copolymer from Example 1 in ethylbenzene was fed continuously to the first stirred kettle at a rate of 0.5 kg / h. A 1% n-butyllithium solution was also fed continuously to the reactor at a rate of 40 ml / h. The total feed of a mixture of styrene and diphenylethylene in a ratio of 2: 1 was 1.0 kg / h and was divided between the reactors in a ratio of 1: 2: 3: 3. The polymerization temperature in the individual reactors was 70 ° C. (Ri), 70 ° C. (R ₂ ), 80 ° C. (Tx) and 90 ° C. (T ₂ ). The conversion after the last tower reactor was 99.8%. The polymer stream flowing out of the last reactor was mixed with a 1.5-fold excess of water and CO ₂ , based on the initiator. The polymer solution was then fed to a degassing device and degassed at 260 ° C. and 10 mbar.

Volatile Shares: 0.15%

Example 4

The block rubber produced according to Example 2 was, as in

Example 3 described, processed to a molding composition according to the invention.

Inlets to reactor 1:

20% block copolymer solution according to Example 2 in toluene

Feed rate 0.4 kg / h

1% n-butyllithium solution in cyclohexane

Feed rate: 40 ml / h

Inlets to reactor 1, 2, 3, 4:

Mixture of styrene and 1, 1-diphenylethylene in a ratio of 1.5: 1.0 and in a total amount of 1.2 kg / h, which was divided between the reactors in a ratio of 1: 2: 3: 3. The reaction temperatures were:

70 ° C (Ri) 80 ° C (R ₂ ) 80 ° C (Ti) 95 ° C (T ₂ )

The conversion after the 2nd tower reactor was 99.5%. 5

Working up was carried out according to Example 3.

Examples 5 and 6

0 All tests were carried out in a double-walled 2 1 stirred reactor with a heating jacket, equipped with an anchor stirrer, with rigorous exclusion of moisture and air under a nitrogen atmosphere. Before each experiment, the reactor was rendered inert with a boiling BuLi solution in cyclohexane. The sec-5 butyllithium solution in cyclohexane was 0.5 molar.

Example 5

Molecular structure: 0 Ii-Bu- (S / DPE) 1- (S / DPE) 2

I ₂ - (S / DPE) 1 with I = sec-butyl and Iι: I ₂ = l: 22.4

Molar masses [g / mol]:

Bu 200 000 25 (S / DPE) 1 60 000

(S / DPE) 2 60 000

Reaction:

30 time [min] inflow quantity temp. [° C] comments

0 CH 500 ml 25 0 s-BuLi 0.541 ml 25

0-120 Bu 54.09g 67-73 120 DPE 7.53 g 69 color change yellow-red 35 120 S 8.7g 69 orange solution

180 CH 300m 60 CH = Cyclohexane 180-270 DPE 176.5 g 60-75 Simultaneous inflow of S and

40 180-270 204g 60-75 DPE over 90 min; phase separation (turbidity) at 215 min

270 ethanol 1 ml 60 decolorization of the silky shimmering orange

45 colored solution to white Refurbishment:

The product was acidified with formic acid and stabilized with 1.35 g of Irganox 1076 and Irganox 3052 and 0.5% Tπsnonylphenyl phosphite. The cyclohexane (CH) was removed in vacuo overnight at 60 ° C. The white mass was subsequently dried at 180 ° C. for 2 hours and pressed into test specimens at 250 ° C.

Yield: 450 g (100% conversion); volatile shares: 0.25%;

T _g (DSC): 158 ° C and - 90 ° C

Monomer composition (FT-IR): S: 47.3%, DPE: 40.9%,

1, 4-trans-Bu: 7.4%, 1,4-cιs-Bu: 3.5%, 1,2-Bu: 1, 1%.

A sample was taken after each monomer addition and analyzed by GPC. The molecular weight increase corresponded to the theory; the final sample showed a bimodal distribution with dispersion mediums

Mw / Mn of the two separate peaks of <1.1 each.

The electron micrograph showed capsule particles with an average particle diameter of 0.3 μm.

Example 6

Molecular structure:

Il-Bu- (S / DPE) I2- (S / DP / E) with I = sec-butyl and II: 12 = 1: 22.4

Molar masses [g / mol]:

Bu 200,000

(S / DPE) 60,000

Reaction:

Time [min] Inlet Amount Temp. [° C] Comments

0 CH 500 ml 25

0 s-BuLl 0.541 ml 25

0-120 Bu 54.09g 67-73

120 s-BuLi 12.14m 60

120 CH 300m 60

120-210 DPE 176.5g 60-75 Simultaneous inflow of S and

120-210 204g 60-75 DPE over 90 mm; Phase separation (turbidity) at 225 mm

210 ethanol 1 ml 60 decolorization of the silky shimmering orange solution to white

Refurbishment:

Working up was carried out analogously to Example 1.

Yield: 434 g (100% conversion); volatile components: 0.29%;

T _g (DSC): 158 ° C and - 90 ° C monomer composition (FT-IR): S: 47.0%, DPE: 40.8%, 1,4-trans-Bu: 7.6%, 1, 4-cis-Bu: 3.6%, 1,2-Bu: 1.2%.

A sample was taken after each monomer addition and analyzed by GPC. The molecular weight increase corresponded to the theory; the final sample showed a bimodal distribution with dispersion md Mw / Mn of the two separate peaks of <1.1 each.

Claims

claims

1. Block copolymers with blocks A and B of the following general structure

(A - B) _n A - B - AB - A - BX [(A - B) _n ] _m , X [(B - A) _n ] _m , X [(A - B - A) _n . _m or X [(B - A - B) _n ] _m

in which

A for a block based on service,

B for a block of copolymers of monomers of the general formulas I and II,

With

R _l = H or alkyl radical with 1-22 C atoms R ₂ = H or alkyl radical with 1-22 C atoms R ₃ = H or alkyl radical with 1-4 C atoms a = 0, 1, 2, 3, 4 or 5 b = 0, 1, 2, 3, 4 or 5

stand.

Thermoplastic molding compositions containing as essential components a) 1 to 99% by weight of copolymers from the monomers of the general formulas I and II

0

With

Ri = H or alkyl radical with 1-22 C atoms R ₂ = H or alkyl radical with 1-22 C atoms R ₃ = H or alkyl radical with 1-4 C atoms a = 0, 1, 2, 3, 4 or 5 b = 0.1.

2, 3, 4 or 5

b) 1 to 99% by weight of a block copolymer according to claim 1

wherein component a) is prepared by polymerizing the monomers in the presence of component b).

3. Block copolymers according to claim 1, containing styrene as a monomer of the formula 1 and 1.1-diphenylethylene as a monomer of the formula II.

4. Use of block copolymers according to claim 1 for the manufacture of polymer mixtures with styrene polymers.

5. Thermoplastic molding compositions containing, as essential components, a block copolymer according to claims 1.0-3000 ppm of monomers of the general formula I and 0-500 ppm of monomers of the general formula II.

6. Use of block copolymers or thermoplastic molding compositions according to one of claims 1 to 2 or 4 for the manufacture of fibers, films and moldings.