WO1999001487A1

WO1999001487A1 - 1,1-diphenyl ethylene-based thermoplastic elastomers

Info

Publication number: WO1999001487A1
Application number: PCT/EP1998/003701
Authority: WO
Inventors: Konrad Knoll; Evelin Endres
Original assignee: Basf Aktiengesellschaft
Priority date: 1997-06-30
Filing date: 1998-06-18
Publication date: 1999-01-14
Also published as: DE19727768A1; AU8800098A

Abstract

The invention relates to copolymers or block copolymers, comprising at least one block A of vinyl aromatic monomers a1) and 1,1-diphenyl ethylene or the derivatives thereof whose aromatic rings are substituted, optionally by alkyl groups with up to 22 C atoms a2) which can be obtained by anionic polymerization, in addition to block polymers with at least one block A and at least one optionally hydrogenated block B of diene b) which can be obtained by sequential anionic polymerization.

Description

Thermoplastic elastomers based on 1, 1-diphenylethylene

description

The invention relates to copolymers or block copolymers with at least one block A composed of vinylaromatic monomers a1) and 1,1-diphenylethylene or its derivatives a2) optionally substituted on the aromatic rings with alkyl groups having up to 22 carbon atoms, obtainable by anionic polymerization and Block copolymers with at least one block A and at least one, optionally hydrogenated block B from dienes b), obtainable by sequential anionic polymerization.

Furthermore, the invention relates to a process for the preparation of the copolymers, their use for the production of molding compositions and molding compositions obtainable from the copolymers.

Thermoplastic elastomers (TPE) are polymers, mainly block or graft polymers, with both thermoplastic and elastic properties. Due to the phase separation due to the incompatibility of polymer blocks into a soft phase as a continuous matrix and a hard phase in the form of isolated, usually spherical inclusions, the TPE's behave below the glass transition temperature of the hard phase like physically cross-linked elastomers. However, since they are not chemically cross-linked, they can be processed like thermoplastics above the glass transition temperature of the hard phase. Their production, properties and use are described in detail in "Thermoplastic Elastomers", G. Holden, N. Legge, R. Quirk and E. Schroeder (ed.), 2nd edition, Hanser Publishers, Munich 1996.

The three-block copolymers with the block structure A-B-A are known from US Pat. No. 3,265,765 as thermoplastic elastomers based on styrene-butadiene. Compared to the class of thermoplastic urethanes (TPU), they have better hydrolysis resistance, better miscibility with non-polar blend components such as oils and are generally cheaper in price. Thermoplastic olefins (TPO) show poorer resilience. Due to the lower glass temperature of approx. 90 - 95 ° C of the styrene blocks, the thermoplastic elastomers based on styrene butadiene have a lower heat resistance.

Attempts have therefore been made to increase the glass transition temperature of the styrene block by copolyization with α-methylstyrene or substitution of styrene by α-methylstyrene or by p-tert-butylstyrene. Due to the low ceiling temperature of α-methyl Polymerization with this monomer is difficult with styrene and leads to thermally unstable polymers with a high residual monomer content. Hard blocks based on p-tert. -Butylstyrene, on the other hand, are relatively well tolerated with the polybutadiene blocks and therefore show no or only poor phase separation. However, phase separation is crucial for the formation of morphology and thus for the mechanical property profile of the thermoplastic elastomer.

Thermoplastic elastomers with copolymer blocks (S / DPE)

Basis 1, 1-diphenylethylene and styrene and polybutadiene blocks (B) are described in JP A 3079-613 and by W. Trepka in J. Polym. Sci., Part B (1970), pages 499-503. According to the specified process conditions, the incorporation of 1,1-diphenylethylene takes place only incompletely, which leads to deteriorated mechanical properties.

Copolymers of styrene and 1,1-diphenylethylene with low residual monomer contents are known from WO 95/34586. Block copolymers of copolymer blocks (S / DPE) on the one hand and polybutadiene blocks on the other hand are described in German patent application P 19623415.

The object of the present invention was to provide copolymers or copolymer blocks of vinylaromatic monomers a1) and 1,1-diphenylethylene or its derivatives a2) which are optionally substituted on the aromatic rings with alkyl groups having up to 22 carbon atoms, in particular have a narrow molecular weight distribution even at low molecular weights.

Furthermore, block copolymers with good hydrolysis resistance, thermal stability, high tear strength, good resilience and good heat resistance should be provided. In particular, the heat resistance to thermoplastic elastomers based on styrene-butadiene should be improved with otherwise comparable properties.

Furthermore, a well-feasible process for the preparation of the copolymers should be provided.

Accordingly, copolymers or block copolymers with at least one block A composed of vinylaromatic monomers a1) and 1,1-diphenylethylene or its derivatives a2) optionally substituted on the aromatic rings with alkyl groups having up to 22 carbon atoms, were obtainable by anionic ones Polymerization found, wherein to form the copolymer or the block A, a starter solution consisting of the reaction product of an anionic polymer risationsinitiator and at least the equimolar amount of monomers a2) used.

Furthermore, block copolymers with at least one block A and at least one, optionally hydrogenated block B from dienes b)] obtainable by sequential anionic polymerization were found, the following process steps being carried out in succession:

I) Formation of a block A by

1.1) Preparation of a starter solution consisting of the reaction product of an anionic polymerization initiator and at least the equimolar amount of monomers a2),

1.2) adding the remaining amount of monomers a2) and 60 to 100% of the total amount of monomers al),

1.3) adding the remaining amount of monomers a1) after conversion of at least 80% of the monomers added in the previous process steps,

the concentration of the polymerization solution after the last monomer addition being at least 35% by weight,

II) subsequent formation of a block B by

II.1) addition of an additive influencing the polymerization parameters,

II.2) addition of dienes b) and

if necessary, the subsequent steps

III) adding a chain terminating or coupling agent,

IV) hydrogenation of the block copolymer,

V) isolation and processing of the block copolymers in a manner known per se,

VI) addition of stabilizers.

Furthermore, a process for the preparation of the copolymers by anionic polymerization according to the process steps mentioned above was found. The copolymers or the blocks A consist al from vinyl aromatic monomers) and 1, 1-diphenylethylene or its rule to the aromati ^¬ rings optionally having alkyl groups with up to 22 C atoms, before ^¬ Trains t having 1 to 4 carbon atoms such as methyl , Ethyl, i- and n-propyl and n-, i- or tert-butyl substituted derivatives a2). ) Are as vinyl- arbmatische al monomers preferably styrene and its sub ^¬ in α-position or on the aromatic ring with 1 to 4 C-atoms-substituted derivatives, for example α-methylstyrene, p-methylstyrene, ethylstyrene, tert. -Butylstyrene, vinyl toluene used. The unsubstituted is particularly preferred as monomer a2)

1, 1-Diphenylethylene used itself. The molar ratio of the units which are derived from 1,1-diphenylethylene or its derivatives a2) to units which are derived from the vinylaromatic monomer al) is generally in the range from 1: 1 to 1:25, preferably from 1: 1.05 to 1:10 and particularly preferably in the range from 1: 1.1 to 1: 3.

The copolymers or blocks A are preferably randomly structured and have a molecular weight Mw of generally 1,000 to 500,000, preferably 3,000 to 100,000, particularly preferably 4,000 to 30,000. Copolymers or a block A made of styrene are particularly preferred and 1, 1-diphenylethylene. For applications in which high heat resistance is particularly important, the molar ratio of monomers a2) to monomers al) is chosen to be as close as possible to 1: 1 and glass transition temperatures of the copolymers or blocks A in the range from 120 to 180 ° C. are obtained .

In principle, all dienes are suitable as diene b) for block B, but preference is given to those with conjugated double bonds such as 1,3-butadiene, isoprene, 2,3-dimethylbutadiene, 1,3-pentadiene, 1,3-hexadienes, phenylbutadiene, Piperylene or mixtures thereof. 1,3-Butadiene and isoprene are particularly preferably used. The diene block can be partially or completely hydrogenated or unhydrated. The hydrogenation of polyisoprene blocks leads to ethylene-propylene blocks or from polybutadiene blocks to polyethylene or polyethylene-butylene blocks corresponding to the 1,2-vinyl portion of the unhydrogenated butadiene block. The hydrogenation makes the block copolymers more thermostable and, above all, more resistant to aging and weathering. The molecular weights Mw of the blocks B are generally in the range from 10,000 to 500,000, preferably from 20,000 to 350,000 and particularly preferably from 20,000 to 200,000. The glass transition temperatures of the blocks B are generally below -30 ° C., preferably below -50 ° C. The proportion by weight of the sum of all blocks A to the total block copolymer is generally 5 to 95% by weight. For use as thermoplastic elastomers, this proportion is preferably 5 to 50% by weight, particularly preferably 25 to 35% by weight, for use as impact-resistant, transparent materials 50 to 95% by weight, preferably 65 to 85% by weight. -%.

For the suitability as thermoplastic elastomers, the morphology is important, which arises due to the incompatibility of blocks A and B. The blocks B aggregate in the soft phase, which forms the continuous matrix and is responsible for the rubber-elastic behavior at use temperature. Blocks A are predominantly in the form of isolated, mostly spherical inclusions, which act as physical cross-linking points. Symmetrical three-block copolymers or star block copolymers with external blocks A are particularly suitable as thermoplastic elastomers.

The anionic polymerization is initiated using organometallic compounds. The usual alkali metal alkyls or aryls can be used as initiators. Organic lithium compounds are expediently used, such as ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert. -Butyl-, phenyl-, hexyldiphenyl-, hexamethylenedi-, butadienyl-, isoprenyl- or polystyryllithium. 1, 1-Diphenylhexyl lithium is particularly preferably used, which is easily obtainable from the reaction of 1, 1-diphenyl ethylene with n- or sec-butyllithium. The amount of initiator required results from the desired molecular weight and is generally in the range from 0.002 to 5 mol percent, based on the amount of monomer to be polymerized.

Suitable solvents are solvents which are inert towards the organometallic initiator. It is expedient to use aliphatic, cycloaliphatic or aromatic hydrocarbons with 4 to 12 carbon atoms such as pentane, hexane, heptane, cyclopentane, cyclohexane, methylcyclohexane, decalin, iso-octane, benzene, alkylbenzenes such as toluene, xylene or ethylbenzene or suitable mixtures.

After the molecular weight has been built up, the "living"

If necessary, polymer ends are reacted with customary chain terminating or coupling agents in amounts which usually depend on the amount of initiator used. Proton-active substances or Lewis acids such as water, alcohols, aliphatic and aromatic carboxylic acids and inorganic acids such as carbonic acid, phosphoric acid or boric acid are suitable as chain terminators.

The block copolymers 2 -Dibromethan, bischloromethylbenzene, silicon tetrachloride, dialkyl or diaryl can bi- or mehrfunktio- nelle compounds, for example, halides of aliphatic or araliphatic hydrocarbons such as 1, siliziumdichlorid, alkyl or Arylsiliziumtrichlorid, tin tetrachloride, polyfunctional aldehydes, such as Therephtalsäuredialdehyd, Ketones, esters, anhydrides or epoxides can be used. Carboxylic acid esters such as ethyl acetate are preferably used as coupling agents if the block copolymer is not hydrogenated. Hydrogenated block copolymers are preferably used

1,2-dibromoethane or diepoxides, especially diglycidyl ethers, such as 1,4-butanediol diglycidyl ether.

Lewis bases such as polar, aprotic solvents or hydrocarbon-soluble metal salts can be used, for example, as an additive influencing the polymerization parameters (randomizer). Lewis bases which can be used are, for example, dimethyl ether, diethyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, tetrahydrofurfuryl ether such as tetrahydrofurfuryl methyl ether or tertiary amines such as pyridine, tri-methylamine, triethylamine and tributylamine or peralkylated bisaminomethylamine or olemethylamine. These are usually used in concentrations of 0.1 to 5 percent by volume based on the solvent. Among the metal salts which are soluble in hydrocarbons, preference is given to using alkali or alkaline earth metal salts of primary, secondary and above all tertiary alcohols, particularly preferably the potassium salts such as potassium triethyl carbinolate or potassium tetrahydrolinaloolate. The molar ratio of metal salt to initiator is usually 1: 5 to 1: 200, preferably 1: 30 to 1: 100.

The selection and quantity of the randomizer are selected depending on the desired end product. For polymers which are not intended for hydrogenation and if, for example, a high 1,4-vinyl content is desired when using butadiene, a hydrocarbon-soluble potassium salt is preferably used. Tetrahydrofuran is preferably used for polymers which are subsequently to be hydrogenated. The amount is chosen so that, for example, a 1,2-vinyl content of about 20 to 50% results when using butadiene. In the process according to the invention, the total amount of monomers a2) is preferably initially introduced into a solvent and the polymerization initiator is added. However, it is also possible to add parts of the monomers a2) or the solvent only at a later point in time. The amount of polymerization initiator results from any protic impurities in monomers and solvents which can be removed by titration, plus the amount which results from the desired molecular weight and the total amount of monomer to be polymerized.

10 quantity calculated. Preferably n- or sec-butyllithium is used, which within a few hours, usually in the range from 0.5 to 40 hours at 20 to 70 ° C. with the monomers a2) completely to 1, 1-diphenylhexyllithium or the corresponding substituted derivatives. To the preferred to 40 to

60 to 100%, preferably 70 to 90%, of the total amount of monomers a1) required to form block A are metered in at a temperature of 15 ° C. The feed time depends on the reactivity of the monomers used and the concentration and is generally between 0.5 and 10 hours at one

20 temperature from 40 to 70 ° C. The remaining amount of the monomers a1) is generally added after a conversion of more than 80%, preferably more than 95%, of the monomers presented or previously added. Block A is polymerized at a high monomer concentration, with a reduction in the residual monomers a2) being achieved

25 can be. In general, the concentration of the polymerization solution after the last monomer addition is at least 35% by weight, particularly preferably above 50% by weight.

In the production of the block copolymers with at least one block B, first a block A as described above, then a block B is formed by sequential anionic polymerization.

After formation of the A block, before addition of dienes b), the addition of the polymerization solution which influences the polymerization parameters is added. Block B is then polymerized by adding dienes b). Before or during the addition of the diene, it is advisable to dilute the reaction mixture with an inert solvent in order to ensure adequate mixing and heat dissipation. The polymerization temperature for block B is preferably 50 to 90 ° C., particularly preferably 50 to 70 ° C. if polar, aprotic solvents are used as randomizers.

45 It would also be possible to repeat the process steps with the exception of the starter solution and thus to arrive at block sequences (AB) _n with n an integer greater than 1 or only a further add another block A. However, this is generally not carried out since the randomizer added in process step II.1 generally disrupts the copolymerization of the monomers al) and a2) and would have to be removed from the reaction solution, or leads to polymers with poorer properties.

The A-B block copolymers obtained can be terminated by chain termination or coupling agents or, in the case of bifunctional coupling agents, linked to form linear three-block copolymers or in the case of more functional coupling agents to form star-shaped block copolymers.

The process according to the invention is not restricted to solution polymerization. For example, the method can also be easily applied to dispersion polymerization. For this purpose, it is advantageous to use a dispersing medium which is inert to the anionic polymerization initiators and in which the A block is not soluble, such as propane, butane, isobutane, pentane or its branched isomers, hexane, heptane, octane or isoctane. In order to obtain a small particle size, 0.1 to 2% by weight of a dispersant is generally added. Suitable dispersants are e.g. Styrene / butadiene two-block copolymers with the highest possible molecular weight of, for example, over 100,000 g / mol.

The block copolymers according to the invention can then be hydrogenated by the customary methods. The hydrogenation of the block copolymers can be carried out according to the rules which are generally known for reactions on polymers on the one hand and for the hydrogenation of olefinic double bonds on the other hand. Catalysts made of metals of the iron group, in particular nickel and cobalt in combination with suitable reducing agents such as aluminum alkyl, are suitable for this.

For example, a solution of the hydrogenation catalyst is conveniently prepared as follows: A 20% solution of aluminum triisobutyl in hexane is added to a 1% solution of nickel acetyl acetonate in toluene at room temperature, the weight ratio of nickel acetylacetonate to triisobutyl aluminum in the range of 1 : 4 lies. After the weakly exothermic reaction has subsided, the fresh catalyst solution is added to the polymer solution and hydrogen is added. 1.5 g (0.15% by weight) of nickel acetylacetonate are sufficient per kg of polymer; if the reaction mixture is particularly pure, 0.15 g is sufficient. The hydrogenation rate that can be achieved depends on the catalyst concentration, hydrogen pressure and reaction temperature. Desired degrees of hydrogenation of over 95% are at 15 bar hydrogen partial pressure and temperatures between 180 and 200 ° C already reached after 30 to 120 minutes. At temperatures around 120 ° C, the hydrogenation takes 8 to 16 hours. A good mixing of the hydrogen gas is a prerequisite for a good space-time yield. This requires an effective stirrer with good vertical mixing, which also creates a surface so that the gas can dissolve. So-called fumigators are very suitable for this. After the hydrogenation has ended, the colloidally distributed nickel, which colors the polymer solution black, can be oxidized with a decolorization using a hydrogen peroxide / acetic acid mixture.

The hydrogenation can of course also be carried out with other homogeneous and heterogeneous hydrogenation catalysts, particularly on an industrial scale. The hydrogenation over the fixed bed catalyst is particularly interesting because contamination of the polymer by catalyst residues is avoided.

The polymer solution is worked up by the customary methods of polymer technology, for example by degassing in extruders or cases with polar solvents such as alcohols or by dispersing in water and removing the solvent by stripping.

The block copolymers are usually mixed with stabilizers. Suitable stabilizers are, for example, sterically hindered phenols such as Irganox® 1076 or Irganox® 3052 from Ciba-Geigy, Basel or α-tocopherol (vitamin E).

The block copolymers can also be adjusted by adding plasticizers with regard to their mechanical properties such as elasticity and ratcheting ability. Plasticizers which are compatible with the soft phase formed from the B blocks, such as aliphatic mineral oil, are preferred. They are usually used in amounts of 10 to 90% by weight, based on the molding composition.

Furthermore, the block copolymers can be processed into molding compositions and homogeneously mixed with compatible polymers and other additives, such as processing aids, lubricants and degassing agents, fillers and reinforcing materials and flame retardants, in customary amounts.

The copolymers or copolymer blocks A produced by the process according to the invention have a narrow molecular weight distribution even with low molecular weights Mw below 40,000 g / mol, in particular below 15,000 g / mol. This is particularly so important for block copolymers which are used as thermoplastic elastomers. A broad molecular weight distribution of the blocks A leads to a high proportion with a very short block length and thus to a greater compatibility with the elastomeric phase formed from the blocks B. This proportion is therefore not effective for physical crosslinking in thermoplastic elastomers.

Examples:

Purification of 1,1-diphenylethylene (DPE)

Commercially available DPE was on a column of minde ^¬ least 50 theoretical plates; distilled at 99.8% purity (spinning band column for larger quantities column with Sulzer packings). The mostly pale yellow distillate is filtered through a 20 cm Alox column (Woelm alumina for chromatography, anhydrous), titrated with 1.5 N sea butyllithium to a strong red color and distilled over 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 used as the solvent was dried over anhydrous aluminum oxide and titrated with the adduct of sec-butyllithium and 1,1-diphenylethylene until it turned yellow. The 1,1-diphenylethylene (DPE) was distilled off from sec-butyllithium (s-BuLi). Styrene (S) and butadiene were dried over alumina at -10 ° C just before use.

The coupling agents, ethyl acetate and 1,2-dibromoethane, were dried over aluminum oxide. 1,4-butanediol diglycidyl ether (Grilonit ^® RV 1806 from Ems-Chemie, Linz, Austria) was brought to a purity of 99.5% by means of fractional distillation in a high vacuum at 0.1 mbar.

The molecular weights were measured by means of gel permeation chromatography in THF against polystyrene standards from Polymer Laboratories. Detection using refractometry.

As a measure of the efficiency of the coupling step, the coupling yield from the GPC distribution (gel permeation chromatography) was determined as the ratio of coupled products (in the examples below, three-block copolymers) to the sum of coupled products and uncoupled polymers. The determination of the double bond content was determined by Titra ^¬ tion Wijs (iodometry).

The mechanical properties were determined depending on the temperature on standard small bars in a tensile test according to DIN 53 455.

Manufacture of unhydrogenated S / DPE-Bu-S / DPE three-block copolymers

Example 1:

2.9 kg of cyclohexane, 0.79 kg of 1,1-diphenylethylene and 150 ml of a 1 molar s-butyllithium solution in n-hexane were placed in a 50 l reactor and stirred at 50 ° C. for 14 h. The solution was then heated to 60 ° C. and 1.88 kg of styrene were added over the course of 6 minutes. After 10 minutes, another 0.21 kg

Styrene metered in at 1.5 kg / h. 25 minutes after the styrene addition had ended, the mixture was diluted with 18.1 kg of cyclohexane. The S / DPE copolymer block obtained had a molecular weight M _n of 9804 g / mol, M _w of 11854, Mp (peak maximum) of 11990, M _w / M _n of 1.21 and a glass transition temperature of 128 ° C. 2 ml of a 10% strength by weight potassium tetrahydrolino olate solution were added to the polymer solution cooled to 50 ° C. Subsequently, 2.04 kg of butadiene were metered in at 8 kg / h, then 4.08 kg at 4 kg / h. After a subsequent reaction of 110 minutes at 50 ° C., 40 ml of a 3-molar solution of ethyl acetate in cyclohexane were added. The block copolymer obtained had a molecular weight M _w of 117280, the coupling yield was 90%. The viscosity number (0.5% in toluene) was 93, the melt flow index MVI (200 ° C / 21.6 kg) 10.9 ml / 10 min. The double bond content was determined according to Wijs to be 66.5%.

The block copolymer obtained was stabilized with 63 g of trisnonylphenyl phosphate (TNPP), 27 g of vitamin E, 45 g of octadecyl-3 (3,5-di-tert-butyl-4-hydroxyphenyl) propionate (Irganox® 1076 from Ciba-Geigy) and 27 g 2, 6-di-tert-butyl-p-cresol (Kerobit® TBK) and 112.5 ml of a 4 molar formic acid solution in ethanol were added.

The stabilized block copolymer could be processed without the addition of oil on a ZSK 25/2 twin screw extruder at 180 ° C. The mechanical properties were determined on injection molded standard bars and are summarized in Table 1. Example 2:

8.4 kg of cyclohexane, 0.98 kg of 1, 1-diphenylethylene and 120 ml of a 1 molar s-butyllithium solution in n-hexane were placed in a 50 1 reactor and stirred at 50 ° C. for 14 h. 2.62 kg of styrene were then added at 12 kg / h, the temperature being kept at 50.degree. 30 minutes after the styrene addition had ended, the mixture was diluted with 12.6 kg of cyclohexane. The S / DPE copolymer block obtained had a molecular weight M _n of 15146 g / mol, M _w of 17391 g / mol, Mp of 18332 and M _w / M _n = 1.15 and a glass transition temperature of 130 ° C. 10 ml of a 10% strength by weight potassium tetrahydrolinaloolate solution were added to the polymer solution. Then 1.80 kg of butadiene were added at 8 kg / h, then 3.60 at 4 kg / h. The viscous orange-colored polymer solution turned gray after an after-reaction of 1.5 h. 70 ml of a 3 molar solution of ethyl acetate in cyclohexane were then added at 50 ° C. The block copolymer obtained had a molecular weight M _w of 121720 g / mol, the coupling yield was 89%. The viscosity number (0.5% in toluene) was 91, the melt flow index (200 ° C / 21.6 kg) 1.9 ml / 10 min. The double bond content was determined to be 50% according to Wijs.

The block copolymer obtained was stabilized with 63 g of TNPP, 27 g of vitamin E, 45 g of 2'-acryloyloxy-3, 3 '-di-tert-butyl-2' - hydroxy-5, 5'-dimethyldiphenylmethane (Irganox® 3052 or Ciba-Geigy) and 27 g of 2, 6-di-tert-butyl-p-cresol (Kerobit® TBK) and 90 ml of a 4 molar formic acid solution in ethanol.

The stabilized block copolymer was extruded on a twin-screw extruder ZSK 25/2 at 180 ° C. with the addition of 30% white oil DAB 10 (Minog® 70 from Wintershall AG).

Example 3:

1.5 kg of cyclohexane, 1.67 kg of 1, 1-diphenylethylene and 300 ml of a 1 molar s-butyllithium solution in n-hexane were placed in a 50 l reactor and stirred at 50 ° C. for 14 h. Then 1.21 kg of styrene was added at 1 kg / h, the temperature being kept at 50.degree. 30 minutes after the styrene addition had ended, the mixture was diluted with 19.5 kg of cyclohexane and cooled to 40.degree. The S / DPE copolymer block obtained had a molecular weight Mn of 3754 g / mol, M _w of 4445 g / mol, Mp of 4676 g / mol, M _w / M _n = 1.18 and a glass transition temperature of 152 ° C. 70 ml of freshly titrated tetrahydrofuran were added to the polymer solution. Subsequently, 2.04 kg of butadiene were metered in at 8 kg / h, then 4.08 at 3 kg / h. After a post-reaction of 20 minutes at 40 ° C. mixed with 35 ml of 1,4-butanediol diglycidyl ether. The block copolymer obtained had a molecular weight M _w of 58180 g / mol, the coupling yield was 88%. The viscosity number (0.5% in toluene) was 55. The Wijs double bond content was found to be 52.4%. The 1,2-vinyl content was 43.2%.

Example 4:

1.5 kg of cyclohexane, 1.12 kg of 0 1, 1-diphenylethylene and 57.1 ml of a 1 molar s-butyllithium solution in n-hexane were placed in a 50 1 reactor and stirred at 50 ° C. for 14 h. 0.8 kg of styrene were then added at 1 kg / h, the temperature being kept at 50.degree. 30 minutes after the styrene addition had ended, the mixture was diluted with 22.5 kg of cyclohexane and cooled to 40.degree. The 5 S / DPE copolymer block obtained had a molecular weight M _n of 9450 g / mol, M _w of 10420 g / mol, Mp of 10220 g / mol, M _w / M _n = 1.10. 70 ml of freshly titrated tetrahydrofuran were added to the polymer solution. Then 1.36 kg of butadiene were metered in at 8 kg / h, then 2.72 at 3 kg / h. After a post-reaction of 20 minutes at 50 ° C., 8.3 ml of 1,4-butanediol diglycidyl ether were added. The block copolymer obtained had a molecular weight M _w of 213,500 g / mol, the coupling yield was 85%. The viscosity number (0.5% in toluene) was 55. The double bond content was found to be 59.7% according to Wijs. The 5 1,2-vinyl content was 42.6%.

Example 5:

1.5 kg of cyclohexane, 1.67 kg of 0 1, 1-diphenylethylene and 300 ml of a 1 molar s-butyllithium solution in n-hexane were placed in a 50 1 reactor and stirred at 50 ° C. for 14 h. Then 1.21 kg of styrene was added at 1 kg / h, the temperature being kept at 50.degree. 30 minutes after the styrene addition had ended, the mixture was diluted with 19.5 kg of cyclohexane and cooled to 40.degree. The

35 S / DPE copolymer blocks obtained had a molecular weight M _n of 4480 g / mol, M _w = 5096 g / mol, Mp of 5277 g / mol, M _w / M _n of 1.14. 70 ml of freshly titrated tetrahydrofuran were added to the polymer solution. Subsequently, 2.04 kg of butadiene were metered in at 8 kg / h, then 4.08 at 3 kg / h. After an after-reaction

40 of 20 minutes at 40 ° C was mixed with 19.4 ml of 1,2-dibromoethane. The block copolymer obtained had a molecular weight M _w of 56662 g / mol, the coupling yield was 83%. The viscosity number (0.5% in toluene) was 47. The double bond content was found to be 60.8% according to Wijs. The 1,2-vinyl content was

45 43%. Manufacture of hydrogenated S / DPE-Bu-S / DPE three-block copolymers

Example 6

Preparation of the hydrogenation catalyst:

In a round bottom flask, 1125 ml of a nickel acetylacetonate in toluene (approx. 10 g / 1) saturated at room temperature were added with stirring to a solution of 192.5 ml of a 20% by weight solution of triisobutylaluminum in n-hexane. In the slightly exothermic reaction, isobutanol escaped and the temperature rose to 50 ° C.

The polymer solution from Example 3 was heated to 60 ° C. in a 50 1 stirred reactor and a freshly prepared catalyst suspension was added. The mixture was then hydrogenated at 120 ° C. and a pressure of 18 bar with hydrogen. After 25 h, a residual double bond content of 22.6% was determined. After a further 17.5 h the solution was cooled to 60 ° C. The double bond content was 18.5%.

The reaction solution was then treated oxidatively with 300 ml of a mixture of 3.6 l of water, 360 ml of a 30% hydrogen peroxide solution and 200 ml of 98% acetic acid at 60 ° C., the residue was washed with water and dried.

For stabilization, the hydrogenated S / DPE-Bu-S / DPE block copolymer was mixed with 0.1% by weight of Irganox® 3052 and Kerobit® TBK.

The viscosity number (0.5% in toluene) was 51 ml / g.

The mechanical properties were determined on standard small bars (punched out from press plates) at 23 ° C. Tensile strength: 25 MPa; Elongation at break: 1014%; Shore hardness A: 69.

Example 7

The polymer solution from Example 4 was hydrogenated analogously to Example 6. The double bond content was 2.6%. The Shore hardness A was 54.7. Example 8

Preparation of the hydrogenation catalyst:

To a suspension of 15 g nickel acetylacetonate in 250 ml

A solution of 350 ml of a 20% by weight solution of triisobutylaluminum in n-hexane was added to toluene under nitrogen and vigorous stirring and the mixture was left to react for 15 minutes.

The polymer solution from Example 5 was heated to 90 ° C. in a 55 1 stirred reactor and a freshly prepared catalyst suspension was added. The mixture was then hydrogenated at 140 ° C. and a pressure of 18 bar with hydrogen. After 3 and 6 hours, the catalyst suspension was replenished (based in each case on 10 g of nickel acetylacetonate). After 24 hours, a residual double bond content of 2% was determined.

The reaction solution was then treated oxidatively with 300 ml of a mixture of 3.6 l of water, 360 ml of a 30% strength hydrogen peroxide solution and 200 ml of 98% strength acetic acid at 60 ° C., the residue was washed with water and dried.

For stabilization, the hydrogenated S / DPE-Bu-S / DPE block copolymer was mixed with 0.1% by weight of Irganox® 3052, 0.1% by weight of Irganox® 1076 and Kerobit® TBK.

The viscosity number (0.5% in toluene) was 50 ml / g. The melt flow index MVI (200 ° C / 21.6 kg) was 15.7 ml / 10 min.

Double bond content 3.1%. The mechanical properties are summarized in Table 1.

Table 1 lists the mechanical properties of the unhydrogenated S / DPE-Bu-S / DPE block copolymer from Example 1 and the hydrogenated S / DPE-ethylene-S / DPE block copolymer from Example 8 at different temperatures. The results show the very high heat resistance of the block copolymers according to the invention.

Table 1: Mechanical properties

Sample failure; n.b., not determined

Claims

claims

1. Copolymers or block copolymers with at least one block A composed of vinylaromatic monomers a1) and 1,1-diphenylethylene or its derivatives a2) optionally substituted on the aromatic rings with alkyl groups with up to 22 carbon atoms, obtainable by anionic polymerization, characterized in that that a starter solution consisting of the reaction product of an anionic polymerization initiator and at least the equimolar amount of monomers a2) is used to form the copolymer or the block A.

2. Block copolymers with at least one block A according to claim 1 and at least one, optionally hydrogenated block B.

Serve b), obtainable by sequential anionic polymerization, characterized in that the following process steps are carried out in succession:

I) Formation of a block A by

1.1) Preparation of a starter solution consisting of the reaction product from an anionic polymerization initiator and at least the equimolar amount of monomers a2),

1.3) Add any remaining amount

Monomers al) after a conversion of at least 80% of the monomers added in the preceding process steps,

II) subsequent formation of a block B by

II.1) addition of an additive influencing the polymerization parameters,

II.2) addition of dienes b) and

if necessary, the subsequent steps III) adding a chain terminating or coupling agent,

IV) hydrogenation of the block copolymer,

V) isolation and processing of the block copolymers in a manner known per se,

VI) addition of stabilizers.

3. Block copolymers according to Claim 2, characterized in that the block copolymers mean symmetrical three-block copolymers or star block copolymers with external blocks A produced by bi- or multifunctional coupling agents, the total of blocks A being in the range from 5 to 50% by weight, based on the total block copolymer.

4. Block copolymers according to claims 2 to 3, characterized in that in process step III) carboxylic acid esters, double halogenated aliphatic or araliphatic hydrocarbons or diglycidyl ethers of aliphatic alcohols are used as the coupling agent.

5. Non-hydrogenated block copolymers according to claims 2 to 4, characterized in that a hydrocarbon-soluble metal salt is used as an additive influencing the polymerization parameters in process step II.1).

6. Hydrogenated block copolymers according to claims 2 to 4, characterized in that in process step II.1) a polar, aprotic solvent is used as an additive influencing the polymerization parameters.

7. A process for the preparation of copolymers according to the process steps according to claims 1 or 2.

8. Use of copolymers according to claims 1 to 6 for the production of molding compositions.

9. Molding compositions obtainable from the copolymers according to claim 8.