DE102005012210A1 - Preparation of homo- or copolymer comprises anionic polymerization of styrene monomer and/or diene monomer in the presence of an initiator composition comprising potassium hydride, alkali metal compound and aluminum organyl - Google Patents

Abstract

Preparation of homo- or copolymer comprises anionic polymerization of styrene monomer and/or diene monomer in the presence of an initiator composition comprising potassium hydride, at least one alkali metal compound from alkali metal alcoholate, alkali metal carboxylate or alkali metal amid and at least one aluminum organyl.

Description

• a) Kaliumhydrid,
• b) mindestens eine Alkalimetallverbindung ausgewählt aus Alkalimetallalkoholat, Alkalimetallcarboxylat und Alkalimetallamid und
• c) mindestens ein Aluminiumorganyl.

The invention relates to a process for the preparation of homopolymers or copolymers of styrene monomers or diene monomers or mixtures thereof by anionic polymerization in the presence of an initiator composition containing

• a) potassium hydride,
• b) at least one alkali metal compound selected from alkali metal alcoholate, alkali metal carboxylate and alkali metal amide and
• c) at least one aluminum organyl.

Homo- or copolymers of styrene monomers (vinylaromatic monomers, e.g. Styrene) and / or diene monomers (for example, butadiene or Isoprene) produced by various polymerization processes, for example by free-radical or anionic polymerization. The by anionic Polymerization obtained polymers have over the radical way received some advantages on products, i.a. lower residual monomers and oligomer contents. Radical and anionic polymerization are completely different. In radical polymerization, the reaction proceeds via free Radicals and e.g. used peroxide initiators, whereas anionic polymerization proceeds via "living" carbanions and, for example Alkalimetallorganylverbindungen be used as initiators.

The anionic polymerization proceeds much faster and leads to higher Turnover, as the radical polymerization. The temperature control of the exothermic Reaction is difficult due to the high speed. That can use of so-called retardants (such as Al, Zn or Mg organyl compounds) encounter, which lower the reaction rate. The viscosity of the reaction mixture generally increases so rapidly in anionic rubber production that a dilution the reaction mixture with an inert solvent is required. After consumption of the monomers, i. at the end of the polymerization, will preferably with a chain stopper, e.g. a protic substance like alcohols, broken off. The anionic polymerization of styrene and / or butadiene is described, for example, in WO-A 98/07765 and WO-A 98/07766 described.

US Pat. No. 3,655,790 describes organomagnesium-alkali metal hydride complexes M _n MgR ¹ R ² H _n where M = Na, K, Li, Cs; R ¹ and R ² = C _3-15 alkyl, aryl, aralkyl; n = 1/2, 1, 2, 3, and their use as reducing and metallating agents.

The U.S. Patents 3,691,241 and 3,817,955 disclose a method of polymerization various monomers, i.a. Butadiene, isoprene and styrene, using the organomagnesium-alkali metal hydride complexes described in US Pat. No. 3,655,790.

in the In contrast to the metal complexes disclosed above used according to the invention Initiator compositions no magnesium and no magnesium organyls.

WO-A 98/07765 discloses initiators for the anionic polymerization, containing the metal organyls R ¹ M ¹ with M ¹ = Li, Na, K, R ¹ = hydrogen, C _1-10 -alkyl, C _6-20 -aryl, C _7-20 alkyl-substituted aryl, and R ² _n M ² with M ² = n-valent element of the groups 2a, 2b or 3a of the periodic table, R ² = hydrogen, halogen, C _1-20 -alkyl, C _6-20 aryl. In addition, a corresponding polymerization process for styrene or diene monomers is disclosed.

In WO-A 03/091296 describes an anionic polymerization process for homo- or copolymers of styrene monomers and / or diene monomers with a Initiator composition containing LiH, NaH or KH as alkali metal hydride, and an aluminum organyl.

The not pre-published German patent application number 102004026324.8 from 26.05.04 describes a similar process for the preparation of mixtures from styrenic polymers and certain vinyl aromatic-diene-vinyl aromatic triblock copolymers using an alkali metal alkyl, aryl, aralkyl or hydride (the latter on page 6, line 4).

None the above documents mentions the Use of alkali metal alcoholates, carboxylates or amides at the initiation.

The DE-A 196 15 533 teaches certain block copolymers of Vinylaromatblöcken and Vinylaromatic-diene blocks, by anionic polymerization by means of lithium alkyl in the presence a soluble Potassium salt, for example, a Kaliumalkoholats be obtained.

In WO-A 99/42506 are block copolymers of vinyl aromatic monomers and dienes which are in the presence of an alkali metal organyl (i.e., an alkyl, aryl, or aralkyl) or alkoxide, and a Magnesium, aluminum or zinc organyls.

The The latter two publications do not disclose alkali metal hydrides as initiators.

The initiator systems known hitherto are not always satisfactory in terms of the polymerization rates or reaction times achievable with them. In addition, can be with ih In some cases, the microstructure of the diene rubber, in particular the content of 1,2- and 1,4-linkages, can not be precisely adjusted. However, this would be desirable because the ratio of 1,2 to 1,4 linkages significantly affects the mechanical properties of the diene homo- or copolymer or molded articles made therefrom.

It The task was to remedy the disadvantages described. Especially the task was to provide an alternative method with the homo- and copolymers of styrene and diene monomers in a shorter time to be obtained. Furthermore should allow the procedure Polymers with defined contents of 1,2- or 1,4-linkages manufacture.

Accordingly, became Found the initially defined method. Preferred embodiments of Invention are the subclaims refer to.

at the method according to the invention become styrene monomers and / or diene monomers by anionic polymerization polymerized to homopolymers or copolymers.

When Styrenic monomers are all vinylaromatic monomers suitable, for example Styrene, α-methylstyrene, p-methylstyrene, ethylstyrene, tert-butylstyrene, vinylstyrene, vinyltoluene, 1,2-diphenylethylene, 1,1-diphenylethylene or mixtures thereof. Styrene is particularly preferably used.

When Diene monomers are all polymerizable dienes into consideration, in particular 1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 2,3-dimethylbutadiene, Isoprene, piperylene or mixtures thereof. Preference is given to 1,3-butadiene (short: butadiene), isoprene or mixtures thereof.

Conveniently, If the monomers are used in the process-typical required Purity, i. one removes interfering impurities such as residual moisture, polar substances, oxygen immediately before the polymerization in in a known manner.

you may use one kind or more kinds of monomers, i. the procedure is suitable for homopolymerization and for copolymerization. Provided one prepares copolymers is the proportion of styrene monomers in the total amount of monomers used usually 5 to 99, preferably 5 to 95 and particularly preferably 10 to 90 wt .-%. Of the at 100 wt .-% missing remainder is diene monomer.

• a) Kaliumhydrid,
• b) mindestens eine Alkalimetallverbindung ausgewählt aus Alkalimetallalkoholat, Alkalimetallcarboxylat und Alkalimetallamid und
• c) mindestens ein Aluminiumorganyl, polymerisiert.

According to the invention in the presence of an initiator composition containing

• a) potassium hydride,
• b) at least one alkali metal compound selected from alkali metal alcoholate, alkali metal carboxylate and alkali metal amide and
• c) at least one aluminum organyl polymerized.

It there is the notion that the potassium hydride a) as an initiator the anionic polymerization, if it is in the solvent (usually nonpolar, inert hydrocarbons) is dissolved. The organoaluminum c) improves the solubility of the Alkali metal hydrides in the solvent, probably due to complex formation, thus improving the efficacy of potassium hydride. Furthermore The Al-organyl slows the rate of polymerization as a so-called retarder the monomers. The alkali metal alcoholate, carboxylate or amide b) seems to act as a reaction accelerator.

Prefers In addition to potassium hydride no other metal hydrides, for example Sodium hydride or lithium hydride, also used.

potassium hydride can in known manner from potassium metal and hydrogen gas under pressure and at elevated pressure Temperature can be produced, however, is also in chemicals trade available, for example, as a pure solid or suspended in mineral oil or a other inert suspension medium.

The needed Amount of potassium hydride a) depends i.a. according to the desired Molecular weight (molecular weight) of the polymer being prepared should, according to the type and amount of alkali metal compounds used b) and aluminum organyls c), and after the polymerization temperature. In general, from 0.0001 to 5, preferably from 0.001 to 2 and particularly preferably 0.005 to 1 mol% of potassium hydride, based on the total amount of monomers used.

Suitable alkali metal compounds b) (alkoxide, carboxylate or amide) are preferably those of lithium, sodium or potassium, more preferably of sodium or potassium. The following general formulas are preferred embodiments, and M is alkali metal and R, R ¹ and R ^{2 are} independently unsubstituted or substituted alkyl, aryl or aralkyl.

Suitable alkali metal alcoholates b) of the general formula R-OM are, as a rule, those of aliphatic, aromatic or araliphatic alcohols having 1 to 20 C atoms. For example, lithium, sodium or potassium methoxide, ethanolate, n-propanolate, isopropanolate, n-butoxide, sec-butoxide, tert-butoxide, n-pentoxide, isopentanolate, hexanolate, amyl alcohol are suitable holat, phenolate, menthol, 2,4-di-tert-butylphenolate, 2,6-di-tert-butylphenolate, 3,5-di-tert-butylphenolate, 2,4-di-tert-butylphenolate butyl 4-methylphenolate and trimethylsilanoate. The methanolates, ethanolates, tert-butyl-substituted phenolates or branched alkyl alcohols are preferably used, in particular sodium or potassium tert-butylate, amylate, t-amylate (= 2-methyl-2-butoxide) or -3, 7-dimethyl-3-octanoate.

The Alkali metal alcoholates are commercially available or may be e.g. by reacting the corresponding alcohol with the alkali metal to be obtained.

suitable Alkali metal carboxylates b) of the general formula R-C (O) -OM are customary those of aliphatic, aromatic or araliphatic carboxylic acids with 1 to 20 carbon atoms. Preferably, R is selected from the ones just mentioned Alkali metal alcoholates called radicals R, in particular of methyl, Ethyl, n- and iso-propyl, n-, sec- and tert-butyl, n- and isopentyl, hexyl, amyl, phenyl, 2,4-di-tert-butylphenyl, 2,6-di-tert-butylphenyl, 3,5-di-tert-butylphenyl, 2,4-di-tert-butyl-4-methylphenyl and trimethylsilyl.

The Alkali metal carboxylates are commercially available or may be e.g. obtained by reacting the corresponding carboxylic acid with the alkali metal become.

Suitable alkali metal amides b) of the general formula M-NH ₂ (derivatives of ammonia) are in particular lithium, potassium or sodium amide. In addition, alkali metal amides b) of the general formulas M-NHR or M-NR ¹ R ² (primary or secondary amines in which an H atom is replaced by a metal atom) are suitable, where the radicals R, R ¹ or R ² independently of one another usually contain 1 to 20 C atoms and may be aliphatic, aromatic or araliphatic. The radicals R, R ¹ or R ² are preferably selected from the radicals R. mentioned above for the alkali metal carboxylates.

The Alkali metal amides are commercially available or can e.g. by reaction of ammonia or the corresponding amine with the alkali metal or with an alkali metal organyl become.

Under the alkali metal compounds b) are the alkali metal alcoholates particularly preferred. Very particular preference is given to using potassium or Sodium tert-amylate (= -2-methyl-2-butoxide).

you may also use mixtures of different alkali metal compounds b), for example, mixtures of several alcoholates, or mixtures of Alcoholates and carboxylates and / or amides.

The needed Amount of alkali metal compound b) depends i.a. according to the desired Molecular weight (molecular weight) of the polymer being prepared according to the amount of potassium hydride a) and to the type and quantity of the aluminum organyl c), as well as after the polymerization temperature. The Amount of the alkali metal compound is suitably used as a molar ratio of Alkali metal compound b) - calculated as the sum of all alcoholates, carboxylates and amides b) - to potassium hydride a) specified. Preferred is the molar ratio of alkali metal compound : Potassium hydride 0.01: 1 to 10: 1, preferably 0.05: 1 to 5: 1 and especially 0.1: 1 to 2: 1.

When Organoaluminium c) are the organometallic compounds of the Aluminum with at least one metal-carbon σ bond suitable, in particular the alkyl or Aryl compounds. In addition, you can the aluminum organyls still hydrogen, halogen or via heteroatoms bonded organic radicals, such as alcoholates or phenolates, on the aluminum contain. The latter are for example by complete or partial hydrolysis, alcoholysis or aminolysis available. It can also mixtures of different organoaluminum be used.

Aluminum organyls of the formula R ₃ Al are preferably used, the radicals R being, independently of one another, hydrogen, halogen, C _1-2 O -alkyl or C _6-20 -aryl. Particularly preferred organoaluminum compounds are the trialkylaluminum compounds such as triethylaluminum (TEA), triisobutylaluminum (TIBA), tri-n-butylaluminum, triisopropylaluminum and tri-n-hexylaluminum. Particular preference is given to using TIBA or TEA or mixtures thereof.

When Organoaluminium c) can also be used by partial or complete hydrolysis, Alcoholysis, aminolysis or oxidation of alkyl or Arylaluminiumverbindungen arise. Examples are diethylaluminum ethoxide, diisobutylaluminum ethoxide, Diisobutyl- (2,6-di-tert-butyl-4-methyl-phenoxy) aluminum (CAS-No. 56252-56-3), methylaluminoxane, isobutylated methylaluminoxane, Isobutylaluminoxane, tetraisobutyldialuminoxane or bis (diisobutyl) alumina.

The required amount of aluminum organyl depends, for example, on the desired retardation effect, the polymerization temperature, the type and amount (concentration) of the monomers used, the amount of potassium hydride and the desired molecular weight of the polymer. The amount of organoaluminum is suitably used as a molar ratio of organoaluminum c) to Potassium hydride a) indicated. The molar ratio of organoaluminum: potassium hydride is preferably 0.1: 1 to 5: 1, preferably 0.2: 1 to 3: 1, and particularly preferably 0.5: 1 to 1.5: 1.

In addition, can one concomitantly use in the polymerization reaction polar compounds or Lewis bases. They are basically All literature known additives of anionic polymerization suitable. They generally contain at least one O, N, S or P atom that over has a lone pair of electrons. Preferred are ethers and amines, e.g. Tetrahydrofuran, diethyl ether, Tetrahydropyran, dioxane, crown ethers, alkylene glycol dialkyl ethers, e.g. Ethylene glycol monoethyl ether, ethylene glycol dimethyl ether as e.g. Diethylene glycol dimethyl ether (diglyme), N, N, N ', N'-tetramethylethylenediamine, N, N, N', N ", N" -pentamethylenetriamine, 1,2-bis (piperidino) ethane, pyridine, N, N, N ', N', N ", N" -hexamethyltriethylenetriamine and phosphoric acid hexamethyltriamide.

The Polar compounds or Lewis bases act as activators and increase in many make the conversion of the polymerization or increase the reaction rate. You can Furthermore the proportions of the various vinyl linkages in butadiene or isoprene polymers to control and thus influence the microstructure of the rubber. If they increase the reaction rate, their amount is convenient so that the reaction rate of the entire approach smaller than in an approach that is without the addition of retarding Components performed becomes. This is done using less than 500 mol%, preferably less as 200 mole% and especially less than 100 mole% of the polar compound or Lewis base, based on the initiator composition.

Prefers the process is characterized in that no alkali metal alkyls, aryls or -arylalkyls used, or the reaction mixture contains these Connections only in ineffective quantities.

Also In the process according to the invention, magnesium organyls are preferred or zinc organyls also used, or the reaction mixture contains them Connections only in ineffective quantities.

ineffective Quantity means that the polymerization reaction by this amount is not significantly affected. Particularly preferably used one beside the one mentioned Aluminum organyls also no other organometallic elements of an element the second or third main group or the second subgroup of the periodic table, e.g. the organyls of the elements Be, Mg, Ca, Sr, Ba, B, Ga, In, Tl, Zn, Cd and Hg, or they are only ineffective amounts included.

at the implementation The polymerization is usually before the monomers and gives Potassium hydride, alkali metal compound and aluminum organyl as well optionally polar compounds or Lewis bases added. The can Ingredients of the initiator composition separated from each other or added together be, as such or solved or suspended in a solution or suspending agent (hereinafter collectively as a solvent designated). As a solvent in particular inert hydrocarbons, more particularly aliphatic, cycloaliphatic or aromatic hydrocarbons, such as Cyclohexane, methylcyclohexane, pentane, hexane, heptane, isooctane, benzene, Toluene, xylene, ethylbenzene, decalin or paraffin oil, or their mixtures. Cyclohexane and toluene are particularly preferred.

at co-addition of the initiator composition ingredients you too first prepare the initiator composition and prior to use mature (age) for a while. The observed aging process is probably due to a complex formation of the metal compounds, the slower than the mixing process. The maturing time is in the Usually at least about 2 minutes, preferably at least 5 minutes, especially at least 20 minutes, and up to 480 hours. The mixture of initiator components can be performed in any mixing unit, for example in a stirred reactor. For the continuous Manufacture are particularly heatable pipes, possibly with static Mixing elements, or continuous flow stirred tank.

The Polymerization may be in the absence or presence of a solvent carried out become. If a solvent is used, one expediently an aliphatic, isocyclic or aromatic hydrocarbon or Hydrocarbon mixture, such as benzene, toluene, ethylbenzene, xylene, Cumene, hexane, heptane, octane or cyclohexane. Preference is given to solvents with a boiling point above 75 ° C used. Particular preference is given to using toluene or cyclohexane. Unless you have a solvent used, it can be used in the later workup, e.g. by Degassing of the resulting polymer, then e.g. by Collect condensation, clean by distillation if necessary, and reuse.

Without solvent One works usually at temperatures over 100 ° C, at which melting of polymers. In the solution polymerization works usually at temperatures from 0 to 250, preferably 20 to 200 ° C.

To Termination of the polymerization, i. after consumption of the monomers, the polymerization is stopped. During and after completion the polymerization, i. even after the monomers are consumed, are present in the reaction mixture "living" polymer chains, so when renewed Monomer addition restart the polymerization reaction immediately would, without having to add polymerization initiator again. By Addition of a chain stopper will terminate the living polymer chains terminated irreversibly.

As termination agents all proton-active substances and Lewis acids come into consideration. Suitable examples are water, and C ₁ -C ₁₀ alcohols such as methanol, ethanol, isopropanol, n-propanol and the butanols. Also suitable are aliphatic and aromatic carboxylic acids such as 2-ethylhexanoic acid, and phenols. Also, inorganic acids such as carbonic acid (solution of CO ₂ in water) and boric acid can be used. Preferred termination agents are alcohols, in particular methanol or ethanol.

The inventive method for the preparation of the polymers may be discontinuous or continuous, be carried out in any pressure and temperature resistant reactor, where it is basically possible is, remixing or not remix de Reactors (i.e. reactors with stirred tank or tubular reactor behavior). The procedure leads depending on Choice of initiator concentration and composition, specifically applied procedure and other parameters, such as temperature and possibly temperature profile, to polymers with high or low Molecular weight. For example, stirred tanks, tower reactors, loop reactors are suitable and tubular reactors or tube bundle reactors with or without fittings. Built-ins can be static or movable Be internals. Further details on the design of the reactors and the operating conditions are the documents WO 98/07765 and WO 98/07766 to remove.

To the polymerization of the monomers and the reaction termination, the Reaction mixture are worked up on the resulting polymer. The reaction mixture contains next to the desired For example, polymers used in polymerization and demolition Auxiliary and concomitant substances and possibly unreacted monomers (so-called. Residual monomers), and optionally oligomers or low molecular weight polymers as unwanted By-products of the polymerization. In the execution of the polymerization as solution For example, the reaction mixture is a polymer solution and contains as an adjuvant especially the solvent. By the workup, for example by degassing be Residual monomers and oligomers, and in particular the solvent, separated. The degassing is in the usual way in common Devices performed.

When Product of the process according to the invention receives For example, homopolymers such as polystyrene (PS or GPPS, general purpose polystyrene), polybutadiene (PB) and polyisoprene (PI), or copolymers such as. impact-resistant Polystyrene (high impact polystyrene, HIPS) and styrene-butadiene block copolymers (S-B polymers or P-S-B for short). The inventive method thus allows the production of thermoplastic molding compositions (e.g., PS or HIPS) and elastomers (e.g., PB, PI, P-S-B).

The Styrene-butadiene block copolymers may be e.g. linear diblock copolymers S-B or triblock copolymers S-B-S or B-S-B (S = styrene block, B = butadiene block), as obtained by anionic polymerization according to the inventive method receives. The block structure is essentially created by first styrene alone polymerized anionically, whereby a styrene block is formed. To Consumption of the styrene monomer is changed to the monomer by monomeric butadiene and anionically polymerized to form a butadiene block (so-called sequential Polymerization). The resulting diblock polymer S-B can by another monomer change to styrene to give a triblock polymer S-B-S may be polymerized if desired. The same applies mutatis mutandis for triblock copolymers B-S-B starting with butadiene.

In the triblock copolymers, the two styrene blocks can be the same size (same molecular weight, ie symmetrical structure S ₁ -BS ₁ ) or different sizes (different molecular weight ie asymmetric structure S ₁ -BS ₂ ). The same applies mutatis mutandis to the two butadiene blocks of the block copolymers BSB. Of course, block sequences SSB or S ₁ -S ₂ -B, or SBB or SB ₁ -B ₂ , are possible. The above are the indices for the block sizes (block lengths or molecular weights). The block sizes depend, for example, on the monomer amounts used and the polymerization conditions.

Instead of the rubber-elastic "soft" butadiene blocks B or in addition to the blocks B, blocks B / S may also be present and are also soft and contain butadiene and styrene, for example randomly distributed or as depending on the type and amount of a randomizer used (Randomizers) tapered structure (tapered = gradient from styrene-rich to styrene-poor or vice versa) If the block copolymer contains multiple B / S blocks, the absolute amounts, and the relative Shares of styrene and butadiene in the individual B / S blocks are the same or different. In the latter case, different blocks (B / S) ₁ , (B / S) ₂ , etc. are obtained.

When Styrene-butadiene block copolymers are also quad and polyblock copolymers suitable.

The mentioned block copolymers may be a have linear structure as described above. However, they are also branched or star-shaped Structures possible and for some applications preferred. Branched block copolymers are obtained in known manner, e.g. by grafting reactions of polymeric "side branches" onto a polymer backbone.

Star-shaped block copolymers are formed, for example, by reacting the living anionic chain ends with an at least bifunctional coupling agent. Such coupling agents are described, for example, in US Pat. Nos. 3,985,830, 3,280,084, 3,637,554 and 4,091,053. Preferred are epoxidized glycerides (eg epoxidized linseed oil or soybean oil), silicon halides such as SiCl ₄ , or divinylbenzene, as well as polyfunctional aldehydes, ketones, esters, anhydrides or epoxides. Also suitable for the dimerization are dichlorodialkylsilanes, dialdehydes such as terephthalaldehyde and esters such as ethyl formate. By coupling identical or different polymer chains it is possible to produce symmetrical or asymmetrical star structures, ie the individual star branches can be identical or different, in particular contain different blocks S, B, B / S or different block sequences. Further details on star-shaped block copolymers can be found, for example, in WO-A 00/58380.

The used above monomer names styrene and butadiene are also exemplary for other vinylaromatic monomers or diene monomers.

at The styrene-butadiene block copolymers do not need all the blocks after the method according to the invention getting produced. For example, you can have at least one block with an initiator composition according to the invention containing potassium hydride, alkali metal alcoholate, carboxylate or amide, and organoaluminum polymerize, and one or more others blocks the same block copolymer according to another method not according to the invention, for example with organolithium compounds or organomagnesium compounds, produce.

The according to the inventive method available impact-resistant Polystyrene (HIPS) contains beside the polystyrene matrix as a rubber component e.g. polybutadiene, Polyisoprene, or, preferably, styrene-butadiene block copolymers. In this case, the rubber component according to the inventive method or by prior art methods, e.g. by anionic polymerization using organolithium compounds or by radical polymerization.

at By anionic polymerization produced rubbers is the rubber is usually dissolved in a solvent or monomeric styrene. In the inventive method need the Rubbers are not from the solvent to be disconnected (although this is also possible). Rather, you can the solution of the rubber together with solvent process directly to the HIPS. This is added to the rubber solution, the if necessary, allow to react beforehand by addition of chain stopper was, monomeric styrene and the initiator composition described above and the mixture is anionically polymerized by the process according to the invention, i.e. it polymerizes styrene in the presence of the rubber.

Inventive polymer is also a HIPS containing rubber according to the invention, wherein the styrene matrix according to another than the inventive method was polymerized in the presence of the rubber.

Therefore includes the obtainable by the method according to the invention HIPS such HIPS polymers where either the rubber component or the styrene matrix or both components prepared by the process according to the invention were.

at the styrene-butadiene block copolymers, the polybutadiene and the Polyisoprene also allows the process according to the invention a control of the content of 1,2- or 1,4-vinyl linkages in polybutadiene or polyisoprene. Because the mechanical properties of these polymers also from the 1,2- or 1,4-vinyl content of polybutadiene or polyisoprene can be determined, thus enabling the method the production of polymers with tailored properties.

In As a rule, the content of 1,4-linkages decreases with decreasing amount of potassium hydride (concentration of KH in the reaction mixture) too. He also usually takes with higher Polymerization temperature too.

If, for example, not according to the invention, sodium metal in tetrahydrofuran is used instead of the above initiator composition, then a polyisoprene produced in this way has a high content of 1,2-vinyl linkages, which is a different property profile results, in particular other mechanical properties.

The obtainable by the process according to the invention Polymers are also distinguished by a low content of residual monomers or oligomers. This advantage falls in particular in the styrene-containing polymers PS, HIPS and P-S-B ins Weight, because of the low content of styrene residual monomers and styrene oligomers an afterthought Degassing - e.g. on a vented extruder, associated with higher costs and detrimental thermal damage of the polymer (depolymerization) - makes superfluous.

The Polymers can be conventional additives and Contain processing aids, e.g. Lubricants or mold release agents, Colorants such as e.g. Pigments or dyes, flame retardants, Antioxidants, stabilizers against exposure to light, fibrous and powdery filling or reinforcing agents or antistatic agents, as well as other additives, or mixtures thereof.

suitable Lubricants and mold release agents are e.g. Stearic acids, stearyl alcohol, stearic acid esters or amides, metal stearates, montan waxes and those based on Polyethylene and polypropylene. Pigments are, for example, titanium dioxide, Phthalocyanines, ultramarine blue, iron oxides or carbon black, and the Class of organic pigments. Under dyes are all dyes to understand that transparent, semitransparent or non-transparent coloring of polymers can be used in particular those which are suitable for coloring styrene or diene homo- or - copolymers are suitable. Such dyes are known in the art.

As flame retardants, for example, the halogen-containing or phosphorus-containing compounds known to the expert, magnesium hydroxide, as well as other conventional compounds, or mixtures thereof can be used. Suitable antioxidants (heat stabilizers) are, for example, sterically hindered phenols, hydroquinones, various substituted representatives of this group, and mixtures thereof. They are available as a topanol ^® or Irganox ^® commercially. Suitable light stabilizers are, for example, various substituted resorcinols, salicylates, benzotriazoles, benzophenones and HALS (Hindered Amine Light Stabilizers), as they are, for example commercially available as Tinuvin ^®.

When examples for fibrous or powdery fillers be carbon or glass fibers in the form of glass fabrics, glass mats or glass silk rovings, chopped glass, glass beads and wollastonite called, more preferably glass fibers. When using Glass fibers can these for better compatibility with the blend components with a size and a primer equipped be. The incorporation of the glass fibers can be both in the form of short glass fibers as well as in the form of endless strands (Rovings). As particulate fillers are carbon black, amorphous silica, Magnesium carbonate (chalk), powdered quartz, mica, mica, bentonite, Talc, feldspar or in particular calcium silicates such as wollastonite and Kaolin. Suitable antistatic agents are, for example, amine derivatives such as N, N-bis (hydroxyalkyl) alkylamines or alkylene amines, polyethylene glycol esters or glycerol mono- and distearates, as well as their mixtures.

The individual additives are used in the usual amounts, so that get closer Information is unnecessary.

The Production of the molding compositions can according to known mixing methods take place, for example by melting in an extruder, Banbury mixer, Kneader, roller mill or calender. However, the components can also be used "cold" and the powdery or granular mixture is only melted and homogenized during processing. To be favoured the components, optionally with the mentioned additives, in one Extruder or other mixing device at temperatures of 100 up to 320 ° C mixed with melting, and discharged. The use of a Extruder is particularly preferred.

Out The molding compounds can be shaped body (also semi-finished products), produce films, films and foams of all kinds.

• – Isopren, gereinigt, von BASF
• – Butadien, gereinigt, von BASF
• – Styrol, gereinigt, von BASF
• – Kaliumhydrid (KH) als 30 gew.-%ige Suspension in Mineralöl, fertige Suspension von Fa. Lancaster; die weiter unten angegebenen KH-Mengen in g beziehen sich auf diese Suspension und nicht auf festes KH als solches
• – Triethylaluminium (TEA) als 1,9 molare Lösung in Toluol, fertige Lösung von Fa. Aldrich; die weiter unten angegebenen TEA-Mengen in ml beziehen sich auf diese Lösung und nicht auf TEA als solches
• – Kalium-tert-amylat (tAmO-K, Kalium-2-methyl-2-butanolat): 2-Methylbutan-2-ol (99%, Fa- Aldrich) und ein molarer Überschuß zerkleinertes Kaliummetall (98%, Fa. Aldrich) wurden über Nacht in der 10-fachen Menge Toluol bei 80°C gerührt; die erhaltene Kalium-tert-amylat-Lösung wurde durch Filtrieren von nicht umgesetztem Kaliummetall abgetrennt
• – Natrium-tert-amylat (tAmO-Na, Natrium-2-methyl-2-butanolat): es wurde vorgegangen wie für Kalium-tert-amylat beschrieben, jedoch wurde Natriummetall statt Kaliummetall verwendet
• – Toluol, gereinigt, von BASF
• – Cyclohexan, gereinigt, von BASF
• – Diethylenglykoldimethylether (Diglyme), 99,5% von Fa. Aldrich
• – Tetrahydrofuran (THF), gereinigt, von BASF
• – Methanol als Kettenabbruchmittel.

All reactions were carried out with stirring, exclusion of moisture and nitrogen atmosphere in a glovebox. The following compounds were used, where "purified" means that was cleaned with aluminoxane and dried:

• - Isoprene, purified, from BASF
• - Butadiene, purified, from BASF
• - Styrene, purified, from BASF
• - Potassium hydride (KH) as a 30 wt .-% suspension in mineral oil, finished suspension from Fa. Lancaster; the quantities of KH stated in g below refer to this suspension and not to solid KH as such
• Triethylaluminum (TEA) as a 1.9 molar solution in toluene, finished solution from Aldrich; the TEA amounts in ml below refer to this solution and not to TEA as such
• Potassium tert-amylate (tAmO-K, potassium 2-me ethyl-2-butoxide): 2-methylbutan-2-ol (99%, Fa-Aldrich) and a molar excess crushed potassium metal (98%, Aldrich) were overnight in 10 times the amount of toluene at 80 ° C touched; the potassium tert-amylate solution obtained was separated by filtration from unreacted potassium metal
• Sodium tert-amylate (tAmO-Na, sodium 2-methyl-2-butoxide): The procedure was as described for potassium tert-amylate, but sodium metal was used instead of potassium metal
• - Toluene, purified, from BASF
• - Cyclohexane, purified, from BASF
• Diethylene glycol dimethyl ether (diglyme), 99.5% from Aldrich
• - Tetrahydrofuran (THF), purified, from BASF
• - Methanol as chain terminator.

The content of 1,4-vinyl linkages in the polymer was determined by taking up ¹³ C nuclear magnetic resonance (NMR) spectra and evaluated. The distribution and number average molecular weight M _{n of} the polymer was determined by GPC (gel permeation chromatography) analysis in tetrahydrofuran; Depending on the polymer used, it was calibrated with polyisoprene, polybutadiene or polystyrene standards.

The The following examples PI relate to polyisoprene, PBu polybutadiene and PS-PBu a styrene-butadiene block copolymer. In all examples was the molar ratio TEA: KH in the initiator mixture 1: 1.

Comparative example PI-1V: Initiation with KH + TEA, without alkali metal alcoholate To 4,3 ml of toluene were at 20 ° C 0.685 ml of the 1.9 molar TEA solution and Add 0.174 g of the 30% by weight KH suspension and ripen for 3 hours calmly.

you put 495 ml of a 2.0 molar solution of Isoprene in cyclohexane and added 5 ml of the initiator mixture. This corresponded to a KH concentration in the reaction mixture of 0.0026 mol / l. The reaction mixture was kept at 80 ° C for 30 hours and fractured then the reaction by addition of 10 ml of methanol.

The solids content of the resulting reaction mixture was 18% by weight. The 1,4-vinyl content in the polyisoprene obtained was 74%. The distribution of the polymer was monomodal and the M _n was 7300 g / mol.

Example PI-2: Initiation with KH + TEA + tAmO-K

It The procedure was as described in Example PI-1V, but gave add so much tAmO-K solution to the initiator mixture before maturing, that the molar ratio tAmO-K: KH was 0.2: 1.

you The reaction mixture was kept at 80 ° C for 6 hours and then the reaction was stopped by adding 10 ml of methanol.

The solids content of the resulting reaction mixture was 82% by weight. The 1,4-vinyl content in the polyisoprene obtained was 74%. The distribution of the polymer was monomodal and the M _n was 9300 g / mol.

Example PI-3: Initiation with KH + TEA + tAmO-K, other tAmO-K concentration

It The procedure was as described in Example PI-2, but gave add to the initiator mixture so much tAmO-K solution that the molar ratio tAmO-K : KH was 0.6: 1.

you kept the reaction mixture at 80 ° C for 2 hours and then broke the reaction by adding 10 ml of methanol.

The solids content of the resulting reaction mixture was 82% by weight. The 1,4-vinyl content in the obtained polyisoprene was 68%. The distribution of the polymer was monomodal and the M _n was 18,800 g / mol.

Example PI-4: Initiation with KH + TEA + tAmO-Na

It The procedure was as described in Example PI-2, but gave the initiator mixture so much tAmO-Na solution (instead of tAmO-K) added that the molar ratio tAmO-Na: KH was 0.2: 1.

you The reaction mixture was kept at 120 ° C for 4 hours and then the reaction was stopped by adding 10 ml of methanol.

The solids content of the resulting reaction mixture was 83% by weight. The 1,4-vinyl content in the polyisoprene obtained was 74%. The distribution of the polymer was monomodal and the M _n was 11,200 g / mol.

Example PBu-1: Initiation with KH + TEA + tAmO-K

To 4.4 ml of toluene were at 20 ° C 0.289 ml of the 1.9 molar TEA solution, 0.074 g of the 30% strength by weight KH suspension and as much tAmO-K solution, that the molar ratio tAmO-K: KH was 0.2: 1 and the mixture ripened for 24 hours calmly.

495 ml of a 2.0 molar solution of butadiene in cyclohexane were added and 5 ml of the initiator mixture added. This corresponded to a KH-Kon concentration in the reaction mixture of 0.0011 mol / l. The reaction mixture was kept for 4 hours at 80 ° C and then broke the reaction by addition of 10 ml of methanol.

The solids content of the obtained reaction mixture was 88% by weight. The 1,4-vinyl content in the obtained polybutadiene was 69%. The distribution of the polymer was monomodal and the M _n was 92,900 g / mol.

Example PBu-2: Initiation with KH + TEA + tAmO-K, other KH concentration

To 4.8 ml of toluene were at 20 ° C 0.144 ml of the 1.9 molar TEA solution, 0.036 g of the 30% strength by weight KH suspension and as much tAmO-K solution, that the molar ratio tAmO-K: KH was 0.2: 1 and the mixture ripened for 24 hours calmly.

you put 495 ml of a 2.0 molar solution of Butadiene in cyclohexane and added 5 ml of the initiator mixture. This corresponded to a KH concentration in the reaction mixture of 0.00054 mol / l. The reaction mixture was kept for 4 hours at 80 ° C and broke then the reaction by addition of 10 ml of methanol.

The solids content of the obtained reaction mixture was 80% by weight. The 1,4-vinyl content in the obtained polybutadiene was 74%. The distribution of the polymer was monomodal and the M _n was 206,000 g / mol.

Example PBu-3: Initiation with KH + TEA + tAmO-K + diglyme, other KH conc.

To 4.5 ml of toluene were at 20 ° C 0.474 ml of the 1.9 molar TEA solution, 0.120 g of 30 wt .-% KH suspension, so much tAmO-K solution, that the molar ratio tAmO-K: KH was equal to 0.2: 1, and that much diglyme given that the molar ratio Diglyme: KH was 0.5: 1, and the mixture ripened for 24 hours calmly.

you put 495 ml of a 2.0 molar solution of Butadiene in cyclohexane and added 5 ml of the initiator mixture. This corresponded to a KH concentration in the reaction mixture of 0.0018 mol / l. The reaction mixture was held at 80 ° C for 90 minutes and fractured then the reaction by addition of 10 ml of methanol.

The solids content of the resulting reaction mixture was 76% by weight. The 1,4-vinyl content in the obtained polybutadiene was 67%. The distribution of the polymer was monomodal and the M _n was 66,400 g / mol.

example PBu-4: Initiation with KH + TEA + tAmO-K + THF, other KH concentration To 4.4 ml of toluene was added at 20 ° C 0.289 ml of the 1.9 molar TEA solution, 0.074g of the 30 wt% KH suspension, so much tAmO-K solution, that the molar ratio tAmO-K : KH was 0.2: 1, and THF was added so that the molar ratio of THF KH was equal to 10: 1, and the mixture ripened for 24 hours.

you put 495 ml of a 2.0 molar solution of Butadiene in cyclohexane and added 5 ml of the initiator mixture. This corresponded to a KH concentration in the reaction mixture of 0.0011 mol / l. The reaction mixture was held at 80 ° C for 90 minutes and fractured then the reaction by addition of 10 ml of methanol.

The solids content of the obtained reaction mixture was 81% by weight. The 1,4-vinyl content in the obtained polybutadiene was 70%. The distribution of the polymer was monomodal and the M _n was 123,000 g / mol.

Example PS-PBu: Initiation with KH + TEA + tAmO-K

To 4.7 ml of toluene were at 20 ° C 0.289 ml of the 1.9 molar TEA solution, 0.074 g of the 30% strength by weight KH suspension and as much tAmO-K solution, that the molar ratio tAmO-K: KH was 0.2: 1 and the mixture ripened for 24 hours calmly.

you put 495 ml of a 2.0 molar solution of Styrene in cyclohexane and added 5 ml of the initiator mixture. This corresponded to a KH concentration in the reaction mixture of 0.0011 mol / l.

The reaction mixture was kept at 80 ° C for 2 hours. A sample was taken. Their solids content was over 99 wt .-%, the distribution of the resulting polystyrene was monomodal and the M _n was 195,000 g / mol.

To the remaining reaction mixture was added 54 ml of butadiene and the mixture for 4 hours at 80 ° C held. Thereafter, the reaction was stopped by adding 10 ml of methanol from.

The solids content of the obtained reaction mixture was 81% by weight. The 1,4-vinyl content in the butadiene portion of the obtained styrene-butadiene block copolymer was 71%. The M _{n of} the block copolymer was 293,000 g / mol.

The examples show that the process according to the invention was able to prepare polyisoprenes, polybutadienes and styrene-butadiene block copolymers with short polymerization times. The reaction time, the molecular weight and the content of 1,4-vinyl linkages in a simple manner be adjusted by varying the initiator composition.

Comparing Comparative Example PI-1V with Example PI-3 according to the invention, the co-use of the alkali metal alcoholate considerably accelerates the polymerization: after 2 hours reaction time, 82% solids content and a polymer with M _n 18,800 g / mol were achieved instead of - not according to the invention - without alcoholate after 30 hours reaction time 18% solids content and a polymer with M _n 7300 g / mol.

Claims (11)

Process for the preparation of homo- or copolymers from styrene monomers or diene monomers or mixtures thereof anionic polymerization in the presence of an initiator composition containing a) potassium hydride, b) at least one alkali metal compound selected of alkali metal alcoholate, alkali metal carboxylate and alkali metal amide and c) at least one aluminum organyl. Method according to claim 1, characterized in that that is used as styrene monomer styrene. Process according to claims 1 to 2, characterized that as diene monomer butadiene, isoprene or mixtures thereof used. Process according to claims 1 to 3, characterized that as the alkali metal compound, a potassium or sodium compound used. Process according to claims 1 to 4, characterized in that the alkali metal compound used is an alkali metal alcoholate. Process according to claims 1 to 5, characterized that is used as Aluminiumorganyl a trialkylaluminum compound. Process according to claims 1 to 6, characterized that the molar ratio Alkali metal compound: potassium hydride 0.01: 1 to 10: 1. Process according to claims 1 to 7, characterized that the molar ratio Organoaluminium: potassium hydride 0.1: 1 to 5: 1. Process according to claims 1 to 8, characterized that one as well co-used polar compounds or Lewis bases. Process according to claims 1 to 9, characterized that no Alkalimetallalkyle, -aryl or -arylalkyl be used. Process according to claims 1 to 10, characterized that one does not use magnesium organyls or zinc organyls.