DE2063291A1 - Process for the production of graft (»polymers - Google Patents

Description

The invention relates to novel, rubber-reinforced, thermoplastic resins and a process for their production such resins. In particular, it relates to thermoplastic ABS and MBS resins. ABS resins generally include Graft copolymer of a mixture of styrene (and / or its polymerizable homologues) and of acrylonitrile (and / or its polymerizable homologues) which are based on a framework of a rubber-like polymer, a.B. one rubbery butadiene polymer graft copolymer! are. MBS resins generally comprise a graft copolymer similar to ABS resins, with the exception that the nitrile is completely or partially replaced by methyl methacrylate (and / or its ρ ο lyra eri erb are homologues). Under the

BATH ORIGINAL 209825/0950

Dr. MOIIer-Bor * Dr. Manitz Dr. Deufel Dipt.-Ing. Finittrwald Dipl.-Ing. Grdmkow

polymerizable homologues of styrene are "5X-methylstyrene, Vinyl toluenes, etc. Among the polymer! Si erable homologues of acrylonitrile are methacrylonitrile and similar nitriles. Among the polymerizable homologues of methyl methacrylate are methyl acrylate, ethyl methacrylate and the like ..

ABS resins and. MBS resins are well-known plastics which combine the desired properties in terms of hardness, impact strength, tensile strength and good flow properties, so that they are suitable for a wide range of plastic applications. The properties of these resins can be varied to meet the requirements of specific end-use applications by changing the proportions of the ingredients. A typical ABS resin can have an addition of 20 % polybutadiene, 60 % polymerized styrene, and 20 % polymerized acrylonitrile.

ABS and MBS resins are usually emulsion graft copolymerized manufactured. In this procedure, an aqueous emulsion of the rubber and the monomers is produced and the graft copolymerization will rait aid in the emulsion initiated by free radical initiators. The execution of such a procedure is, however, in a corporate manner Scale costly, at least in part due to the need to speed up emulsifiers, chain transfer agents, and agents To stop the reaction and the like during the polymerization, and due to the rather complicated coagulation and extraction methods to be used, uru das Obtain resin from the emulsion. The costume for guiding you The process adds significantly to the cost of the finished resin at.

SAD 209825/0950

Highly resilient polystyrene resins, which contain a graft copolymer of styrene on a rubber-like, polymeric framework, for example polybutadiene, are, in contrast, usually produced according to the Dilliger mass or mass suspension polymerization process. In these procedures, the rubber is dissolved in the monomeric styrene in the practical absence of other solvents or hediene, and the mixture is passed through a bulk prepolymerization stage. The monomer graft copolymerizes onto the rubber either only under the influence of heat or, if this is preferred, by initiation with a free-radical polymerization initiator. This "pre-polymerization takes place with agitation up to one stage after the phase inversion, and preferably up to about 20-40% solids content. The inversion, ie the phenomenon observed in the polymerization process, of the polystyrene solution forming a continuous phase, whereby the Rubber cement dispersed as droplets occurs when the amounts of polystyrene and rubber dissolved in styrene are about the same; depending on the amount of rubber added to the styrene, it can occur at about 5-20 % conversion of styrene monomer to polymer In the second stage of the polymerization process, the prepolymerized mixture is further polymerized to practical completion with or without agitation. This can be carried out in the same reaction zone in which the gate polymerization was carried out or in a second seaction zone. Alternatively, an aqueous suspension gel can be added, and the polymerization is b is carried out in suspension at the practical end of the course.

Earlier "attempts, ASS and MBS Harse by the cheaper one To produce bulk or hate suspension polymerization process, made leine sufri edenstell end resins. Even though

209825/0950

BATH ORIGINAL

such resins were produced, their properties exhibited certain deficiencies, particularly in terms of tensile strength and flexural strength. So it was not possible to produce a range of ABS and MBS Har ζ varieties by the bulk or bulk-suspension polymerization process, to meet all the requirements that currently ζ of emulsionspolyHierisierten ABS and MBS Har en are met. Obviously, the inclusion of additional polar graft monomer introduces aggravating factors into the process compared to the manufacture of high impact polystyrene.

The aim of the invention is to provide a method for mass or Bulk suspension polymerisation for the production of ABS and MBS resins to deliver at least this deficiency diminishes.

It has been found that ABS and MBS resins are satisfactory by means of a bulk or bulk suspension polymerization process can be prepared, provided that a mixture of certain polymers is considered to be rubber-like Scaffold for the copolymeric graft resin is used.

According to the invention, the process for the production of ABS and MBS resins is characterized in that a mixture of pre-formed, chewy-gauze-like polymer A and pre-formed polymer B is dissolved in a mixture of graft monomers, the solution thus formed being agitated until it is converted the graft monomer is prepolymerized from about 10 % to about AO% , whereby a dispersion of a solution of these preformed polymers in a solution of a polymer is formed and the solutions are solutions in the remaining graft monomers, and the polymerization of the remaining graft monomers up to at least

209825/0950

50 % conversion is continued, the continued polymerization being carried out in bulk or in aqueous suspension under suspension conditions, and the graft copolymerization product thus formed is recovered, in which the polymer A is a polydiolefin with a high 1,4-content, and the polymer B a polymer of butadiene- (1,3) selected from homopolymers of butadiene- (i, 3) with at least about 0% butadiene units in the 1,2-configuration and copolymer seeds of butadiene- (1,3) with less than 50% by weight of a copolymerizable monomer.

A polybutadiene with a high 1,4-content, in particular a polybutadiene with a high cis-1,4-content, is preferred as the polymer A int. However, polybutadienes are with a 1,4-content of at least 85 % and a cis-1,4-content of 35 ° / ° and. higher also suitable, together with polyisoprene with a high cis-1,4 content.

The polymer B, which is suitable for an application according to the invention, is a polymer of butadiene (1,3) _t which is composed of homopolymers and copolymers of butadiene with less than 50% by weight of a copolymerizable monomer, for example styrene, oC-methylstyrene , Acrylonitrile, methacrylonitrile, methyl methacrylate and the like. The homopolymers contain at least about 50 % and preferably at least about 80 % of the butadiene units in the 1,2-configuration polymerized. The molecular weight of 1,2-polybutadiene can vary within wide limits, although it is preferred, a polymer having an intrinsic Viokosität of less than 5 AEL / Si measured in toluene at 30 ⁰ C, vorzxigsweise of not more than 1 dl / g apply.

- 5 -

ORiGSNAL SN3PECTED

209825/0950; i

In the copolymers of butadiene with copolymerizable monomers, the microstructure of the copolymerized butadiene units is not critical; they can have a high 1,2-Eqnfiguration, or it may consist of a mixture of all possible configurations exist, and no flour to 60 ° o present '/, as they are obtained in free-radical catalyzed polymers. The molecular weight of the copolymers is not critical; solid, rubber-like polymers having a Mooney viscosity (M / L-4 at 1OO ⁰ C) applied of up to about 60, when the viscosity of the starting solution has no meaning. In many processes, however, low-molecular, rubber-like polymers, for example block copolymers with an intrinsic viscosity of about 1 dl / g or less, are preferred. The preferred block copolymers of alkenyl-aromatic hydrocarbons and conjugated diolefins for use as polymer B are those which are derived from butadiene and styrene or 00-methylstyrene. Suitable, preferred block copolymers include those with the general form SBS, SB / S, SB / SS, SB-QC and Ot-B- ^, where S is a block of polystyrene, B is a block of polybutadiene and B / S is a copolymer block of Butadiene and styrene and oO represent a block of poly oO.-mdbhyl styrene.

Low molecular weight, liquid copolymers which contain less than 50% of a copolymerizable monomer and preferably between 10 and 40% by weight of, for example, styrene or acrylonitrile, can advantageously be used according to the invention. A representative example of such copolymers is a terminally carboxylated copolymer of butadiene and acrylonitrile with a molecular weight of less than about 10,000.

209825 / Ö950

111 of the ABS and MBS resins according to the invention are the proportions of graft monomers and rubbers in general evenly to the proportions used in conventional, through Emulsion made ABS and IIBS resins for the same Purposes are applied. The total rubber content is generally within the range from 5 to 30% by weight, the remainder being the grafted monomers. The proportion of styrene (and / or its polymerizable homologues) to acrylonitrile, etc. is suitably of the order from 10: 1 to 1: 2, but preferably from 3'1 »so that the monomeric proportions of the product within the approximate ranges rubber 5 to 30% by weight, styrene, etc. 15 to 75 wt.%, U] id acrylonitrile, etc. 12 to 30 wt.%.

In the method according to the invention and the inventive In products, it is preferred that the ratio of polymer A to polymer B be greater than 1: 1 on a weight basis. Particularly preferably, the ratio is from about 10: 1 to about 1.5 ** 1 »to a certain extent depending on the Properties of the various selected polymers.

As mentioned above, previous attempts to prepare such copolymeric graft resins by the Hasse or bulk suspension polymerization processes resulted in the formation of resins with inadequate properties. If only polybutadiene as the reinforcing rubber, even the most polybutadiene preferred high cis-1,4 - GeImIt of the polymer A of the invention is angeviandt, resins having a poor match dev properties, such as tensile strength, flexural strength, impact strength , the melt flow index, produced by the Ilassesiisponsioiis polymerization process. One or more of these properties cannot be desired by changing the parameters such as the relative nonomeric contents and the polymorisive bionic conditions without abandoning other desirable

- 7 209825/0950

other properties of the resins can be improved. As will be shown in the following examples, "the use of a rubber specified in the invention as polymer B alone in the bulk suspension polymerisation process does not result in resins having a complete set of desired properties. The combination of rubbers, as previously explained, appears necessary for the production of satisfactory J & BS and MBS resins by bulk or bulk suspension polymerization procedures. The resins produced in this way according to the invention have properties which are in all essential respects comparable to those of the resins produced by emulsion polymerisation procedures and they have considerable economic advantages over the latter.The polymers which can be used in the invention as polymer A and polymer B. The processes for their preparation are also known and do not form part of the present invention so that its detailed description is not necessary.

Likewise, the general procedure for bulk or hate suspension graft polymerization is known and does not require a very detailed description. In the first bulk polymerization stage, generally known as prepolymerization, the rubbers are dissolved in the monomers and this solution is then polymerized. The polymerization can be initiated thermally, or it can be initiated by the decomposition of a suitable free radical initiator. In any case, the polymerization takes place at elevated temperatures, for example from 50 to 120 ^° C. The polymerization takes place with movement until a phase inversion has occurred. This can be done visually. must be observed, since the viscosity of the reaction solution

209825/0950

gradually increases, reaches a maximum at the point of phase inversion, and then all of a sudden decreases. The phase inversion depends on the amount of rubber used and it can occur, for example, between 15 ° / ° and JO % conversion of the monomers. This stage is referred to herein as the prepolymerization stage. It is essential that phase inversion be obtained during prepolymerization to ensure that the final resin has the two phases required for high impact strength. If necessary, the prepolymerization can be stopped or inhibited by cooling the reaction mixture to room temperature.

For the suspension polymerization technique in the second polymerization stage, the modifier and further initiator can be dissolved in the reaction mixture, and the aqueous suspension medium is then added. In the method according to the invention, an aqueous solution of polyvinyl alcohol is preferred as the suspension medium. Of course, other suitable suspension media can be used. The polymerization then proceeds at elevated temperatures, usually not less than about from 50 ⁰ O until at least 50% _t vprzugsweise at least 85% conversion of the monomers is reached. The reaction mixture is then cooled and the copolymeric grafts are isolated and recovered by vacuum stripping.

Alternatively, the prepolymerized mixture can be polymerized to its practical completion in the absence of a dispersing medium or solvent, ie in bulk. This second stage of the polymerization is usually carried out at temperatures of about 80 to about 200 ⁰ O ⁰ O. It can be carried out in the same reaction vessel in which the mixture was prepolymerized, or

- 9 -209825/0950

preferably in a second reaction vessel. Since agitation is not required at this stage and the polymerization is carried out at about atmospheric pressure, a disposable container can serve as a convenient reaction vessel. However, it is preferred to operate continuously using, for example, an extrusion polymerizer or a tuna reaction vessel. In the latter case, the prepolymerized, liquid mixture is introduced into the top of the tower and gradually moved downwards. As the graft monomers are polymerized, the reaction temperature is gradually increased so that the polymerization proceeds at a reasonable rate and the reacting mixture is kept liquid. The temperature increases of about 10O ⁰ C in the upper part of the tower at up to about 200 ⁰ C at the foot. The substance emerging from the base of the tower is a molten polymer which is practically completely polymerized and does not contain more than about 10% volatile constituents.

The invention is explained below with reference to examples:

example 1

In this example, a number of investigations have been carried out on Production of ABS resins according to bulk suspension polymerization using a mixture of high cis 1,4 polybutadiene and high 1,2 polybutadiene as framework polymers in various relative proportions .done to each other. In addition, two control tests are carried out carried out in which these Eautschul: e each were applied individually.

Bulk prepolymerization was carried out using a resin kettle with a capacity of 2 1, the one with one with heat transfer coils equipped with a water jacket.

- 10 -

209825/0950

The kettle was fitted with a motorized stirrer with twin four-blade turbine blades equipped. The kettle also came with a reflux condenser, sample lock, and the temperature sensing and regulating device.

In the bulk prepolymerization stage, a solution of the framework polymers in styrene and acrylonitrile monomers was prepared at room temperature with a total volume of about 600 ml. A 70/30 weight ratio of styrene to acrylonitrile was used in each experiment. A small amount, 7 »5 ε» of a conventional antioxidant for polymers, a mixture of alkylated aryl phosphates, was also added for protection. In each experiment, 350 g of styrene ^were: and 150 g of acrylonitrile used as a monomer mixture. The relative proportions of the polymers varied from experiment to experiment. This reaction solution was poured into the resin kettle.

Then, the free-raäLkalisclie initiator, 3.0 g Laurclperoxid added and dissolved, and the reaction mixture was heated to the polymerization temperature of 65 + 4 ⁰ C and stirred at this temperature while vigorously was held up to a point after phase inversion has occurred was (3 to 5 h) The point of this phase inversion was determined visually by observing the viscosity of the reaction mixture, as explained above. After the phase inversion, the prepolymerization was delayed in most experiments by cooling the reaction mixture to room temperature.

The same equipment was used for the suspension polymerization stage applied. The modifier (2.0 g of tert-dodecyl nercaptan) and additional initiator (3jO g lauryl peroxide and 2.0 g of tert-butyl perbenzoate) are added first

- 11 -

BATH ORIGINAL 209825 / 095Q

and, dissolved in the reaction mixture. Then the suspension medium was added. This consisted of 1400 g of water and 50 g of a 3% aqueous solution of polyvinyl alcohol. This suspension was stirred vigorously and warmed to the polymerization temperature of 63 ± 4 ^° C. for a period of about 6 hours in order to complete the polymerization. Typically, the conversion achieved was about 90 % under the conditions of this example.

The graft copolymer product was then recovered by separating the suspension beads from the aqueous serum by filtration. The beads or beads were washed with hot water and cold water and rinsed with steam for 2 hours at above 97 ° to remove any volatile residue. The beads were then dried in a vacuum oven in a nitrogen atmosphere at 115 ° 0 for 3 hours. Suitable, conventional stabilizers were dry mixed with the dried beads, and the beads were then ground and chipped ready for the physical / mechanical investigations. - ^T

In the tests according to the invention, a polybutadiene with a cis-1,4- (content ₄ of 98 % bIb, the reinforcing polymer (polymer A) was used. This polybutadiene had a high molecular weight and a Mooney viscosity I.

Qfl / L 4 at 100 ⁰ C) of 37% ¹ ^ ^e ^ ^was äu ^ eb Iiöeungspolymeri- ·

cation using a cobalt-based Zi, egler catalyst. The polymer B was a low molecular weight polybutadiene with a 1 ^ content of 91 % and an intrinsic viscosity of 0.60, measured in toluene at

■: '

The investigation of the resins was carried out in a manner well known carried out. Rods with a cross-section of 6.4 mm 12.7 by 1/2 ") vairden from the resin; injection molded and the Festig

209025/0950. ·

subjected to tests in a manner known per se. Rockwell hardness was measured according to the standard testing procedure described in ASTM D 78-65, Method A. The results are given below as values on the "E" scale in the usual manner. The flow properties of the resins were tested by determining their melt flow index according to the standard procedure, ie by determining the number of g of polymer which passed through an opening with a diameter of 2.08 mm (0.0825 inches) in 10 minutes at a Temperature of 220 ⁰ C and flow through under a load of 10 kg. The heat distortion temperature was determined according to the ASTM D 648-56 standard. The products were also analyzed for the bound acrylonitrile content to test the final chemical composition.

The type and amount of framework polymers, the results the chemical analyzes and the results of the physical / mechanical investigations of the products of the various Experiments are given in Table I. In every experiment, polymer A was a polybutadiene with a high cis-1,4 ~ Content, the polymer B is a polybutadiene with a high 1,2 content.

The amounts of these polymers are in parts by weight / 100 parts by weight. of the combined graft monomers indicated, i.e. Wt.TIn./100 Gew.TIe, the styrene / acrylonitrile mixture.

209825/0960

Table I.

Trial Fri 1 20,200 2 3 4c Polymer A
(Teas / 100 teas monomers) 14.0 13.0 12.0 - Polymer B
(Tie./10OTIe.monomers) 1.0 2.0 3 * 0 15th 15, ο
(2.8)
6.96 Izod impact test
cm kg / cm ² * ^{egg 2} ^
(ft. lbs / inch) _hel _ ₃ tf Z 14j4 23.5 25.1 4.82
4.28
(6.8) 19.5 Melt flow index
(g / 10 min) j 18.5 15, O ₁ 13.5 380 Tensile strength
at break (kg / cm.). 475 480 460 500 425 Flexural strength
(kg / cm ² ) 540 550: 540 630 17,050 Bending module
(kg / cm ² ) I.
ί
21,650? a 500 22,350

Rockwell R hardness

101 j 101.5; 103 ^: 108.5

Heat bending
temperature ( ⁰ O) i ———-
82 -H ——— 1
i
¹ 81 82 73 .95:
I. 77 % By weight bound
Acrylonitrile 21.8 j
I 21.6
i 21.35 20th 20.7 y

- 14 -

82 5 / .0 9 SO

The experiments marked with 4-c and ^ c are natural Search for controllers that do not fall under the invention, a reinforcing polymer being omitted. she were carried out in exactly the same way as the other experiments, and also examined the resin, and they serve for comparison purposes.

From the results shown in Table I it can be seen that the control test 4-c, in which the only reinforcing polymer was the polybutadiene with a high 1,2-content, resulted in a resin which, in terms of impact resistance, was found both at room temperature and was poor at low temperature and also in terms of the melt flow index, indicating a resin with completely inadequate softening properties. The control test in which only polybutadiene with a high ciB-1.4 content was used gave a resin which was poor in terms of tensile strength, flexural strength and flexural modulus. In contrast, the tests according to the invention produced 1 bit resins with satisfactory properties in all essential points. Although in some cases a melt flow index was found to be lower than that of the resin from control experiment $ c , this is not a problem as the values are still sufficient for normal, commercial use. The substantial improvement in the tensile strength and flexural strength of the resins from Experiments 1 to 3 and comparison with the resins from Experiment 5c is particularly noteworthy.

Example 2

In this example, a number of attempts were made to be / accurate in the same way as described in Example 1, with the exception that the polymer B instead of a polybutadiene with a high 1,2-content a block copolymer of

- 15 - * 209825/0950

General formula: Poly- ~ ö £ - • ■ methylstyrene-polybutadiene-poly (> C-ethylstyrene was. This block cor) olyiaerisate had an intrinsic viscosity "in toluene of 0.3 dl / g and an Oi-ethylstyrene content of 35 Gow./o. The polybutadiene block contained: 69 % Honolieren units · in the 1,2-configuration As in Example 1, the polymer A was a polybutadiene with a high cis-1,4-content. The results of the experiments and. Investigations on the products are listed in Table II. To facilitate comparison, the results of the control experiment 5c ^ of Example 1 are repeated in Table II. ...'-. "

209825/0950

Table II

Experiment no. 6th 7th 8th ■ 9 10 11 5c Polymer Δ
(Tie./1QO parts monomers) 14.25 14.0 13.5 13.0 12.0 9.0 15th Polymer, B.
(Part./1ÖQ He.Monomere) 0.75 1.0 1.5 2.0 3.0 6.0

NJ O CO OD NJ

IzocL impact test cm kg / cm (ft.lbs / inch)

at 25 C

at -34 ° C

25.7 (4.8)

9.10 (1.7)

31.6
(5.9)

10.2
(1.9)

24.6 (4.6)

9.10 (1.7)

20.9 (3.9)

8.56 (1.6)

15.0
(2.8)

7.49
(1.4)

13.9 (2.6)

6.96 (1.3)

15.0 (2.8)

6.96 (1.3)

Melt flow index
(g / 10 min) 7.8 6.7 14.5 14.5 18.6 21.0 19.5 Tensile strength
at break, (kg / cm) 450 480 470 460 475 45O. 350 Flexural strength
(kg / cm ² ) 510 520 510 550 515 530 425 Bending modulus (kg / cm) 21,200 20,700 20,850 22,650 21,200 22,000 17,050 Eockwell E hardness 97 101 99 107.5 101.5 101 93 Thermal bending temperature (C) 87 83 79 82 81 79 77 % By weight of bound acrylonitrile 21.2 21.55 21.5 21.6 21.3 20.7

The same remarkable increase is seen in Table I the tensile strength of the resins compared to the control tests. The melt flow indices of the resins of Runs 6 and 7 are lower than desired for some applications and for this reason the embodiments of the invention shown in Examples 8, 9 »10 and 11 are preferred.

Example 3

In this example a series of experiments would be carried out in exactly the same way as described in Example 1, however, different polymers were used as reinforcing polymer B.

In Experiment 12, the polymer B was a block copolymer of styrene and butadiene of the general form GBS. The Bio el: copolymer had a styrene content of 28.8 wt. / S and an intrinsic viscosity of 0.091 dl / g, measured in toluene at 30 ⁰ C. The butadiene block contained 8.5% of monomer units in the 1,2 configuration and 37 »^ ° / ° i ⁿ the ~ 1.4 ~ cis configuration, with the remainder in the trans-1 ^ - was present configuration.

In the experiment, Ij, the polymer B was an irregular Copolymerisät of styrene and butadiene containing 28 Gews / ό styrene 'and a Mooney viscosity (M / L 4 at 100 ⁰ C) of- 32

exhibited *

The results of tests and investigations on the manufactured Resins are listed in Table III *

^BAD ORi _GiNAL

- 18 -

Table III

Try ITr. Mononero) 12th 0 13th 0 14th 0 Polymer A
(Tie./1OG Tie. Monomers) 13, 0 13, 0 13, 0 Polymer B
(Tie./100 Tie. 2, 2, 2,

Isod ßclilagversuch at 25 ⁰ C 17.1 36.4 21 4th cm ¹ ^ c / cn '" (3.2) (6.8) 0) (ft.lbs / inch) at -34 ° σ 8.56 9.63
(1.0) 42 (1.6) (1, 2)

Sclr-ielzflussinde ::
(3 / IO nin) ^ (° c) 15.0 464 14.0 at:;, Br'ach (kc / c: a '~) 450 520 470 Flexural strength 49c 21,350 560 20,000 102 21,350 Ro c ^ zvjell-ii-Iir.rt c 102 77 104 W ^ ebiccctenreratui GO 20.51 79. G ov: ./ög oV vjici eiic- s
Acrylonitrile 21.3 22.2

-19 -

209825/0950

BATH ORIGINAL

These values show that the substantial increase in the tensile strength, the impact strength, the flexural strength and the flexural modulus, and the hardness of the resins, compared with the use of the polybutadiene with a high ice, 4-grade alone, with these alternative rubbers such as Polymer B "is observed .. ■; '■ ■■■' ■■ .-" ■ '

- patent claims -

. - 20 209 82 ^ 5709 5.0 ^ D original

Claims (3)

Claims 1. Process ■ for the production of high-impact, thermoplastic resins, .thereby g. eke η η ζ ei ch η et that (1) a mixture of preformed, rubber-like polymer A and preformed polymer B in a mixture is dissolved by graft monomers, (2) the mixture thus formed is prepolymerized with agitation up to a conversion of the graft monomers of 10 % to 40 % , a dispersion of a solution of the preformed polymers being formed in a solution of a polymer of the graft monomers, the solutions being solutions in the remaining graft monomers are, (3) the polymerization of the remaining graft monomers is continued up to at least 50 % conversion, this continued polymerization being carried out in bulk or in an aqueous suspension, and (4) the thermoplastic resin thus formed is obtained, in which the polymer A is a polydiolefin with a high 1,4-content, and the polymer B is a polymer of butadiene- (1,3), which is made from homopolymers of butadiene- (1,3) with at least 50 % of the butadiene units in the 1,2-configuration and copolymer seeds of butadiene- (1 ", 3) with less than 50% by weight of a copolymerizable monomer is selected, and wherein the graft monomers comprise a mixture of styrene, a polymerizable homologue of styrene with one or more of the substances acrylonitrile, polymerizable homologues of acrylonitrile, methyl methacrylate and polymerizable homologues of methyl methacrylate. 2. The method according to claim 1, characterized in that that the mixture of the preformed polymers in an amount of 5-30% by weight, based on the total weight of polymer and graft monomers, is used. - 21 - ' BAD ORiGINAL 209825/0950 3. The method according to claim Λ or 2, characterized. 3 e Ii α η η ζ ei chne t that the continued polymer! sation in an aqueous suspension medium, which contains a dilute solution of a polyvinyl alcohol, is carried out at about the same temperature as the Vorpolyiierisatipn. 4-. High impact, thermoplastic resin which contains from about 15 to about 75% by weight of copolymerized styrene and / or its polymerizable homologues, from about 12 to about 30 C-ew.iu copolymerized acrylonitrile, methyl methacrylate and / or their polymerizable homologues and from about 5 to ot './ a 30 Gew.?j a mixture of at least two flexible " Ψ polymers, thereby g 0'.: e η η ζ υ i 3 h 11 ο t that one of the flexible polymers can be. utschul: c.rti ^ es polybutadiene with a high 1,4-content, and the endore dpr flexible polymer is a homopolymer of butadiene- · (1,3) with at least ^ 0% butadiene units in the 1,2-configuration or a copolymer of 1,3-butadiene with less than 50% by weight of styrene, 1-methylstyrene or acrylonitrile as a copolymerizable honor. - 22 - 209825/0950