EP1274754A1

EP1274754A1 - Method for polymerizing conjugated diolefins (dienes) with catalysts of rare earths in the presence of vinyl aromatic solvents

Info

Publication number: EP1274754A1
Application number: EP01925422A
Authority: EP
Inventors: Heike Windisch; Thomas Schnieder; Gisbert Michels; Gerd Sylvester; Pierre Vanhoorne; Heinz-Dieter Brandt
Original assignee: Bayer AG
Current assignee: Bayer AG
Priority date: 2000-03-24
Filing date: 2001-03-12
Publication date: 2003-01-15
Also published as: CN1427854A; JP2003528949A; MXPA02009287A; US20040030071A1; AU2001252182A1; CA2403870A1; WO2001072860A1; RU2002128724A

Abstract

The invention relates to a method for polymerizing conjugated diolefins in the presence of catalysts of rare earths and in the presence of aromatic vinyl compounds, and to the use of these diolefins for producing rubber-modified molding materials, especially of the ABS type and impact-resistant polystyrene (HIPS).

Description

Process for the polymerization of conjugated diolefins (dienes) with rare earth catalysts in the presence of vinyl aromatic solvents

The present invention relates to a process for the polymerization of conjugated diolefins in the presence of rare earth catalysts and in the presence of aromatic vinyl compounds and the use of these diolefins for the production of rubber-modified molding compositions, in particular of the ABS type and impact-resistant polystyrene (HIPS).

The polymerization of conjugated diolefins in the presence of a solvent has been known for a long time and is described, for example, by W. Hoffmann, Rubber Technology Handbook, Hanser Publishers (Carl Hanser Verlag) in Munich, Vienna, New York, 1989. For example, polybutadiene is predominantly produced today by solution polymerization with the aid of coordination catalysts of the Ziegler-Natta type, for example based on titanium, cobalt, nickel and neodymium compounds, or in the presence of alkyl lithium compounds. The solvent used depends heavily on the type of catalyst used. Benzene or toluene and aliphatic or cycloaliphatic hydrocarbons are preferably used.

A disadvantage of the polymerization processes carried out today for the production of polydiolefins, such as BR, IR or SBR, is the complex workup of the polymer solution for isolating the polymers, for example by stripping with water vapor or direct evaporation. A further disadvantage, particularly when the polymerized diolefms are to be further processed as impact modifiers for plastic applications, is that the polymeric diolefms obtained first have to be dissolved again in a new solvent, for example styrene, in order then to give, for example, acrylonitrile-butadiene-styrene copolymers (ABS). or high-impact polystyrene (HIPS). US Pat. No. 3,299,178 claims a catalyst system based on TiCl iodine / Al (isobu) ₃ for the polymerization of butadiene in styrene to form homogeneous polybutadiene. With the same catalyst system, Harwart et al. in Plaste and Kautschuk, 24/8 (1977) 540 describes the copolymerization of butadiene and styrene and the suitability of the catalyst for the production of polystyrene.

US Pat. No. 5,096,970 and EP-A 304 088 describe a process for the preparation of polybutadiene in styrene using catalysts based on neodymium phosphonates, organic aluminum compounds such as di (isobutyl) aluminum hydride (DIBAH), and based on a halogen-containing Lewis acid, such as ethyl aluminum sesquichloride, in which butadiene is converted into styrene without further addition of inert solvents to give a 1,4-cis-polybutadiene. In the examples described, the polymerization of butadiene in styrene takes place at 80 ° C. and a reaction time of up to 6 hours; the butadiene used is converted to polybutadiene with a conversion of over 80%. The rubber solutions in styrene described in the listed patent publications were only used for the production of high-impact polystyrene (HIPS), the rubber being incorporated into the polystyrene matrix. For this purpose, free radical initiators are added to the rubber solutions in styrene after removal of the unreacted diolefin.

Not mentioned in EP-A 304 088 is the possibility of using the rubber solution for the production of ABS.

For the production of ABS, the rubber is used in a matrix of acrylonitrile-styrene copolymers (SAN). In contrast to the production of HIPS, the SAN matrix in ABS is incompatible with polystyrene. If, in addition to the rubber, polymers of the solvent, such as polystyrene, are formed in the polymerization of the diolefms in vinylaromatic solvents, the results in

Manufacture of ABS the incompatibility of the SAN matrix with the polymer vinyl aromatics caused a significant deterioration in the material properties of the ABS.

In the polymerization of butadiene with catalysts based on transition metal compounds and aluminum organyls, as described in EP-A 304 088, however, the vinyl aromatic solvent, e.g. Styrene, no longer stabilized by the reaction of the stabilizer with the aluminum organylene used, so that a high-molecular polymer of the solvent is formed in a side reaction by a thermally induced free-radical polymerization. The dependence of the styrene polymerization rate on temperature and reaction time is known and is described in the literature (see Encycl. Polym. Sei. Eng., Vol. 16, 1989).

On the other hand, under the reaction conditions described in EP-A 304 088, a thermally induced radical copolymerization of 1,3-

Butadiene and styrene with a maximum mass fraction of 10% butadiene is another high-molecular by-product which, owing to the copolymerization parameters known in the literature (see Encycl. Polym. Sei., Vol. 2, 1985, Polymer Handbook, Third Edition, 1989), has a high by-product Polystyrene content with a low butadiene content (<20 mol%) and whose glass transition temperature T _g > 40 ° C.

According to EP-A 304 088, the amount of polymerized styrene is up to 1% based on the amount of monomeric styrene used, which according to the examples with a monomer ratio of 90% styrene and 10% butadiene even under the ideal condition of a complete conversion of butadiene to polybutadiene corresponds to an amount of polymerized styrene of up to 8.2% based on the polybutadiene formed.

In ABS production, this thermoplastic by-product remains in the SAN matrix due to its high molecular weight and acts there through free double Bindings of the butadiene portion as an undesirable crosslinking agent, which causes gel and speck formation, which also leads to a significant deterioration in the material properties of ABS.

It was an object of the present invention to provide a process for the polymerization of conjugated diolefins in vinylaromatic solvents, with which it is possible to prepare high-cis-polydiene rubbers, the mass fraction of the radical-formed by-product based on the polydiene rubber Should be <1% by weight and its comonomer composition should be modified so that the glass transition temperature T _{g of} the polydiene rubber is <0 ° C.

The present invention therefore relates to a process for the polymerization of conjugated diolefins (dienes), which is characterized in that the polymerization of the diolefins in the presence of catalysts consists of

a) at least one compound of the rare earth metals,

b) at least one organoaluminum compound

c) optionally at least one modifier

and in the presence of vinyl aromatic compounds at temperatures from -30 to + 100 ° C, the molar ratio of components (a) :( b) :( c) being in the range from 1: 1 to 1000: 0.1 to 10 , component (a) of the catalyst in amounts of 1 μmol to 10 mmol, based on 100 g of the conjugated diolefin used, and the aromatic vinyl compound in amounts of 50 to 300 parts by weight, preferably 80 to 250 parts by weight and very particularly preferably 100 to 200 parts by weight, based on 100 parts by weight of the conjugated diolefin used, and the conversion of the diolefin used is preferably less than 50 mol%, particularly preferably 10 to 45 mol%, very particularly preferably 20 is up to 40 mol%. As conjugated diolefms (dienes), for example and preferably 1,3-butadiene, 1,3-isoprene, 2,3-dimethylbutadiene, 2,4-hexadiene, 1,3-pentadiene and / or 2-methyl-l , 3-pentadiene can be used.

Suitable compounds of the rare earth metals (component (a)) are, in particular, those which are selected from

an alcoholate of rare earth metals,

a phosphonate, phosphinate and / or phosphate of rare earth metals,

a carboxylate of rare earth metals,

- A complex compound of rare earth metals with diketones and / or

an addition compound of the rare earth metal halides with an oxygen or nitrogen donor compound.

The aforementioned compounds of rare earth metals are, for example, in

EP-A 11 184 described in more detail.

The compounds of the rare earth metals are based in particular on the elements with atomic numbers 21, 39 and 57 to 71. Lanthanum, praseodymium or neodymium or a mixture of elements of the rare earth metals, which contains at least one of the elements lanthanum, are preferably used as rare earth metals. Contains praseodymium or neodymium to at least 10 wt .-%. Lanthanum or neodymium are very particularly preferably used as rare earth metals, which in turn can be mixed with other rare earth metals. The proportion of lanthanum and / or neodymium in such a mixture is particularly preferably at least 30% by weight. Suitable alcoholates, phosphonates, phosphinates and carboxylates of the rare earth metals or as complex compounds of the rare earth metals with diketones are, in particular, those in which the organic group contained in the compounds in particular straight-chain or branched alkyl radicals having 1 to 20 carbon atoms, preferably 1 to 15 carbon atoms , contains, such as and preferably methyl, ethyl, n-propyl, n-butyl, n-pentyl, isopropyl, isobutyl, tert-butyl, 2-ethylhexyl, neo-pentyl, neo-octyl, neo-decyl or neo dodecyl.

The following are examples of preferred rare earth alcoholates:

Neodymium (III) -n-propanolate, neodymium (III) -n-butanolate, neodymium (III) -n-decanolate, neodymium (III) -isopropanolate, neodymium (III) -2-ethylhexanolate, praseodymium (III) -n-propanolate, praseodymium (III) -n-butanolate, praseodymium (III) -n-decanolate, praseodymium (III) -isopropanolate, praseodymium (III) -2-ethylhexanolate, lanthanum ( III) -n-propanolate, lanthanum (III) -n-butanolate, lanthanum (III) -n-decanolate, lanthanum (III) -isopropanolate and lanthanum (III) -2-ethyl-hexanolate are preferred Neodymium (III) -n-butanolate, neodymium (III) -n-decanolate and neodymium (III) -2-ethyl-hexanolate.

Examples of preferred phosphonates, phosphinates and phosphates of the rare earths are: neodymium (III) -dibutylphosphonate, neodymium (III) -dipentyl-phosphonate, neodymium (IΙI) -dihexylphosphonate, neodymium (III) -diheptylphosphonate, neodymium (III) - dioctylphosphonate, neodymium (III) dinonylphosphonate, neodymium (III) diododecylphosphonate, neodymium (III) dibutylphosphinate, neodymium (III) dipentylphosphinate, neodymium (III) dihexylphosphinate, neodhephytyl (III) dym (III) dioctylphosphinate, neodymium (III) dinonylphosphinate, neodymium (III) didodecylphosphinate and neodymium (IodI) phosphate, preferably neodymium (III) dioctylphosphonate and neodymium (III) dioctylphosphinate.

Suitable carboxylates of the rare earth metals are: lanthanum (III) propionate, lanthanum (III) diethyl acetate, lanthanum (III) -2-ethylhexanoate, lanthanum (III) stearate, lanthanum (III) benzoate, lanthanum ( III) cyclohexane carboxylate, lanthanum (III) oleate, lanthanum (IΙI) versatate, lanthanum (III) naphthenate, praseodymium (III) propionate, praseodymium (III) diethyl acetate, praseodymium (III) -2-ethylhexanoate, praseodymium (III) stearate, praseodymium (IΙI) benzoate, Praseodymium (III) cyclohexane carboxylate, praseodymium (III) oleate, praseodymium (III) versatate, praseodymium (III) naphthenate, neodymium (III) propionate, neodymium (III) diethyl acetate, neodymium (III) -2 ethylhexanoate, neodymium (III) stearate, neodymium (ffl) benzoate, neodymium (III) cyclohexane carboxylate, neodymium (III) oleate, neodymium (III) versatate and neodymium (III) naphthenate, preferably neodymium ( III) -2-ethylhexanoate, neodymium (IΙI) versatate and neodymium (III) naphthenate. Neodymium versatate is particularly preferred.

The following are mentioned as complex compounds of rare earth metals with diketones:

Lanthanum (III) acetylacetonate, praseodymium (III) acetylacetonate and neodymium (III) acetyl acetonate, preferably neodymium (III) acetylacetonate.

Examples of addition compounds of the halides of the rare earth metals with an oxygen or nitrogen donor compound are: lanthanum

(IΙI) chloride with tributyl phosphate, lanthanum (III) chloride with tetrahydrofuran, lane than (III) chloride with isopropanol, lanthanum (III) chloride with pyridine, lanthanum (III) chloride with 2-ethylhexanol, Lanthanum (III) chloride with ethanol, praseodymium (III) chloride with tributyl phosphate, praseodymium (III) chloride with tetrahydrofuran, praseodymium (III) chloride with isopropanol, praseodymium (III) chloride with pyridine, praseodymium (III ) chloride with 2-ethylhexanol, praseodymium (III) chloride with ethanol, neodymium (III) chloride with tributyl phosphate, neodymium (III) chloride with tetrahydrofuran, neodymium (III) chloride with isopropanol, neodymium (III) -chloride with pyridine, neodymium (III) chloride with 2-ethylhexanol, neodymium (III) chloride with ethanol, lanfhan (III) bromide with tributyl phosphate, lanthanum (III) bromide with tetrahydrofuran, lanthanum (III ) bromide with iso-

Propanol, lanthanum (III) bromide with pyridine, lanthanum (III) bromide with 2-ethylhexanol, lanthanum (III) bromide with ethanol, praseodymium (III) bromide with tributyl phosphate, praseodyrn (III) bromide with tetrahydrofuran, praseodymium (III) bromide with isopropanol, praseodymium (III) bromide with pyridine, praseodymium (III) bromide with 2-ethylhexanol, praseodymium (III) bromide with ethanol, neodymium (III) bromide with

Tributyl phosphate, neodymium (III) bromide with tetrahydrofuran, neodymium (III) bromide with iso-propanol, neodymium (III) bromide with pyridine, neodymium (III) bromide with 2-ethylhexanol and neodymium (III) bromide with ethanol, preferably lanthanum (III) chloride with tributyl phosphate, lanthanum (III) chloride with pyridine, lanthanum (III) chloride with 2-ethylhexanol, praseodymium (III) chloride with tributyl phosphate, praseodymium (III) chloride with 2-ethylhexanol, neodymium (III) chloride with tributyl phosphate, neodymium (III) chloride with Tetrahydrofuran, neodymium (III) chloride with 2-ethylhexanol, neodymium (III) chloride with pyridine, neodymium (III) chloride with 2-ethylhexanol and neodymium (III) chloride with ethanol.

The components of the rare earths listed in EP-A 727 447 and the allyl compounds of rare earths mentioned in WO 96/31544 can also be used as component a).

Neodymium versatate, neodymium octanoate and / or neodymium naphthenate are very particularly preferably used as compounds of the rare earth metals.

The rare earth compounds can be used both individually and as a mixture with one another. The most favorable mixing ratio can easily be determined by appropriate preliminary tests.

Organometallic compounds of the type used as cocatalysts in the Ziegler-Natta catalysts are preferably used for component b). Compounds of the metals from the groups Ha, Ilb and Illb of the Periodic Table of the Elements should preferably be mentioned, particularly preferably magnesium, calcium, boron, aluminum, zinc, very particularly preferably aluminum and magnesium.

The organometallic compounds to be used for component b) are described in detail, for example, in G. Wilkinson, FGA Stone, EW Abel, Comprehensive Organometallic Chemistry, Pergamon Press Ltd., New York, 1982, Vol. 1 and Vol. 3 as well as in EW Abel, FG Stone, G. Wilkinson Comprehensive Organometallic Chemistry, Pergamon Press Ltd., Oxford, 1995, Vol. 1 and 2.

As component b), which in turn can be used individually or as a mixture with one another, the following are particularly preferably mentioned: dibutyl magnesium, butyl ethyl magnesium, butyl octyl magnesium, trimethyl aluminum, triethyl aluminum, tri-n-propyl aluminum, tri-iso-propyl aluminum, tri-n-butyl aluminum , Tri-isobutyl aluminum, tripentyl aluminum, trihexyl aluminum, tricyclohexyl aluminum, trioctyl aluminum, triethyl aluminum hydride, di-n-butyl aluminum hydride and diisobutyl aluminum hydride, ethyl aluminum dichloride, diethyl aluminum chloride,

Ethyl aluminum sesquichloride, ethyl aluminum dibromide, diethyl aluminum bromide, ethyl aluminum diiodide, diethyl aluminum iodide, di-iso-butyl aluminum chloride, octyl aluminum dichloride, dioctyl aluminum chloride, preferably trimethyl aluminum, triethyl aluminum and iso-aluminum-tri-iso-aluminum-tri-iso-aluminum-tri-iso-aluminum.

Alumoxanes can also be used as component b).

Aluminum-oxygen compounds which, as is known to the person skilled in the art, are obtained as alumoxanes and are obtained by contacting organoaluminum compounds with condensing components, such as water, and the non-cyclic or cyclic compounds of the formula (-Al (R) Represent 0-) _n , where R can be the same or different and represents a linear or branched alkyl group having 1 to 10 carbon atoms, which may also contain heteroatoms, such as oxygen or nitrogen. In particular, R represents methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, n-octyl or iso-octyl, particularly preferably methyl, ethyl or iso-butyl. Examples of alumoxanes are: methylalumoxane, ethylalumoxane and isobutylalumoxane, preferably methylalumoxane and isobutylalumoxane.

The halogen-containing compounds known for Ziegler-Natta catalysts, such as organic ones, can be used as modifiers (component c) Halogen compounds, halogenated inorganic or organometallic compounds of the group Illb, IVb and Vb of the periodic table of the elements.

The following compounds can in particular be used as component c): methyl aluminum dichloride, methyl aluminum sesqichloride, dimethyl aluminum chloride, methyl aluminum dibromide, methyl aluminum sesqibromide. Dimethyl aluminum bromide, ethyl aluminum dichloride, ethyl aluminum sesqichloride, diethyl aluminum chloride, ethyl aluminum dibromide, ethyl aluminum sesqibromide. Diethylalumi- bromide, ethylaluminum diiodide, diethylaluminum iodide, Butylaluminiumdi- chloride, Butylaluminiumsesqichlorid, dibutylaluminum chloride, bromide Butylaluminiumdi-, Butylaluminiumsesqibromid, Dibutylaluminiumbromid, Octylaluminiumdi- chloride, dioctyl, dibutyl tin dichloride, aluminum tribromide, antimony trichloride, antimony pentachloride, phosphorus trichloride, phospho entachlorid, tin tetrachloride, tert-butyl chloride, tert -Butyl bromide, tert-butyl iodide, triphenyl methyl chloride, triphenyl methyl bromide and / or triphenyl methyl iodide, particularly preferably ethyl aluminum dichloride, ethyl aluminum sesqichloride, diethyl aluminum chloride, ethyl aluminum dibromide, ethyl aluminum sesqibromide and / or diethyl.

The organometallic compounds and optionally the modifiers can be used either individually or in a mixture with one another. The most favorable mixture ratio can easily be determined by appropriate requests.

It is also possible to add yet another catalyst component (a), (b) and (c)

Add component (d). This component (d) can be a conjugated diene, e.g. is the same diene that will later be polymerized with the catalyst. Butadiene and / or isoprene are preferably used.

If component (d) is added to the catalyst, the amount of (d) is preferably 1 to 1000 mol, based on 1 mol of component (d), particularly preferably 1 to 100 mol. 1 to 50 mol, based on 1 mol of component (a), are very particularly preferred. used on (d).

In the process according to the invention, the catalysts are used in amounts of preferably 10 μmol to 5 mmol of component (a), particularly preferably 20 μm to

1 mmol of component (a), based on 100 g of the dienes.

Of course, it is also possible to use the catalysts in any mixture with one another.

The process according to the invention is carried out in the presence of aromatic vinyl compounds, in particular in the presence of styrene, α-methylstyrene, α-methylstyrene dimer, p-methylstyrene, divinylbenzene and / or other alkylstyrenes having 2 to 6 carbon atoms in the alkyl radical, such as ethylbenzene , carried out.

The polymerization according to the invention is very particularly preferably carried out in the presence of styrene, α-methylstyrene, α-methylstyrene dimer and / or p-methylstyrene as solvent.

The solvents can be used individually or in a mixture; the most favorable mixture ratio can be easily determined by means of appropriate preliminary tests.

The amount of aromatic vinyl compounds used is preferably 80 to 250 parts by weight, very particularly preferably 100 to 200 parts by weight, based on

100 parts by weight of the diene used.

The process according to the invention is preferably carried out at temperatures from -20 to 90 ° C., particularly preferably at temperatures from 20 to 80 ° C. The conversion of the conjugated diolefin used in the process according to the invention is less than 50 mol%, preferably 10-45 mol%, very particularly preferably 20-40 mol%.

The process according to the invention can be depressurized or at elevated pressure (0.1 to

12 bar).

The process according to the invention can be carried out continuously or batchwise, preferably in a continuous procedure.

The solvent used in the process according to the invention need not be distilled off, but can remain in the reaction mixture. In this way it is possible, for example when styrene is used as solvent, to connect a second polymerization for the styrene, an elastomeric polydiene being obtained in a polystyrene matrix. In an analogous manner, an ethylenically unsaturated nitrile monomer, for example acrylonitrile, can be added to the polystyrene solution before the second polymerization is carried out. In this way you get ABS. Such products are of particular interest as impact-modified thermoplastics.

It is of course also possible to remove part of the solvent and / or the unreacted monomers after the polymerization, preferably by distillation, if appropriate under reduced pressure, in order to obtain the desired polymer concentration.

It is also possible to add the polymer solution before or during the subsequent polymerization of the solvent, which can be initiated in a known manner, for example by free radicals or thermally and by known bulk, solution or suspension polymerization processes in a continuous, semi-continuous or batch mode the optionally added ethylenically unsaturated nitrile monomers, such as acrylonitrile, methyl methacrylate, maleic acid CT / EP01 / 02730

- 13 -

anhydride or maleimides, which can be copolymerized with the vinyl aromatic solvent, and also common aliphatic or aromatic solvents, such as benzene, toluene, dimethylbenzene, ethylbenzene. Hexane, heptane or octane, and / or polar solvents, such as ketones, ethers or esters, which are usually used as solvents and / or diluents for the polymerization of the vinylaromatic solvent.

Vinylaromatic monomers, which are optionally radically polymerized together with ethylenically unsaturated nitrile monomers and thereby form the homogeneous phase (matrix phase) of the molding compositions, are the same ones that were used to prepare the rubber solution. Core-substituted chlorostyrenes can also be used in a mixture with these.

Ethylene-unsaturated nitrile monomers are preferably acrylonitrile and methacrylonitrile, particularly preferably acrylonitrile.

Furthermore, up to 30% by weight, preferably up to 20% by weight, of the total amount of monomers, acrylic monomers or maleic acid derivatives can be used: Methyl (meth) acrylate, ethyl (meth) acrylate, tert-butyl (meth) acrylate, esters of fumaric, itaconic acid, maleic anhydride, maleic esters, N-substituted maleimides such as advantageously N-cycohexyl- or N-phenyl-maleimide , N-alkyl-phenyl-maleimide, further acrylic acid, methacrylic acid, fumaric acid, itaconic acid, or their ide.

The ratio of vinyl aromatic monomers to ethylenically unsaturated

Nitrile monomers in the ABS molding compositions are 60-90% by weight to 40-10% by weight based on the matrix phase. The rubber content in the ABS molding compositions is 5-35% by weight, preferably 8-25% by weight, based on the ABS molding composition. The rubber content in the HIPS molding compositions according to the invention is 1-25% by weight, preferably 3-15% by weight, based on the HIPS molding composition. If the radical polymerization is carried out in solvents, aromatic hydrocarbons such as toluene, ethylbenzene, xylenes and ketones such as acetone, methyl ethyl ketone, methyl propyl ketone, methyl butyl ketone and mixtures of these solvents are suitable as solvents. Ethylbenzene, methyl ethyl ketone and acetone and mixtures thereof are preferred.

The polymerization is advantageously triggered by radical initiators, but can also be carried out thermally: the molecular weight of the polymer formed can be adjusted by means of molecular weight regulators.

Suitable initiators for free-radical polymerization are graft-active, free-radical peroxides such as peroxycarbonates and peroxydicarbonates. Diacyl peroxides, perketals, or dialkyl peroxides and / or azo compounds or mixtures thereof. Examples are azodiisobutyronitrile, azoisobutyric acid alkyl ester, tert-butyl perpivalate, tert-butyl peroctoate, tert-butyl perbenzoate, tert.-

Butyl perneodecanoate, tert-buty] per (2-ethylhexyl) carbonate. These initiators are used in amounts of 0.005 to 1% by weight, based on the monomers.

To adjust the molecular weights, conventional molecular weight regulators such as mercaptans, olefins, e.g. tert-Dodecyl mercaptan, n-dodecyl mercaptan, cyclohexene, terpinolene, α-methylstyrene dimer in amounts of 0.05 to 2% by weight, based on the monomers, are used.

The process can be carried out batchwise, semi-continuously and continuously. In the continuous embodiment, the rubber solution, monomers and, if appropriate, solvents can advantageously be polymerized in a continuously charged, mixed and stirred tank reactor with a stationary monomer conversion after the phase inversion in the first stage of more than 10% and the radical-triggered polymerization in at least one further Level up to a monomer conversion of 30-90% below

Mix in one or more continuously operated stirrers continue boilers in cascade or in a mixing plug flow reactor and / or a combination of both reactor types. Residual monomers and solvents can be made using conventional techniques (for example in heat exchanger evaporators, flash evaporators, strand evaporators, thin-film or thin-film evaporators, screw evaporators, stirred multiphase evaporators with kneading and

Scraper devices) are removed, the use of propellants and entraining agents, e.g. Water vapor, is possible, and can be returned to the process. Additives, stabilizers, anti-aging agents, fillers and lubricants can be added during the polymerization and during the polymer isolation.

The batchwise and batchwise polymerization can be carried out in one or more filled or partially filled, mixed, stirred kettles in series with the rubber solution, monomers and, if appropriate, solvents and polymerization up to the stated monomer conversion of

30-90% can be done.

For better mixing and division of the rubber solution fed in, the syrup can be pumped in a circle over both mixing and shearing organs with continuous and discontinuous operation. Such

Loop reactors are state of the art and can be helpful in adjusting the particle size of the rubber. However, the arrangement of shear members between two separate reactors is more advantageous in order to avoid back-mixing, which leads to a broadening of the particle size distribution.

The molding compositions according to the invention can be processed into molded parts by extrusion, injection molding, calendering, blow molding, pressing and sintering.

As already mentioned above, the method according to the invention is distinguished by particular economy and good environmental compatibility, since the method used Solvent can be polymerized in a subsequent step, the polymer contained in the solvent being used to modify thermoplastics (for example increasing the impact strength).

According to the process according to the invention, it is possible to influence the polymer composition by varying the reaction conditions, such as varying the ratio of diolefins and vinylaromatic solvents used, the catalyst concentration, the reaction temperature and reaction time.

Another advantage of the process according to the invention is that, in the direct polymerization in styrene, it is also possible to prepare and process further such low molecular weight polymers which are difficult to process and store as solids with a high cold flow or high stickiness.

The advantage of low molecular weight polymers is that even with a high one

Content of the polymers the solution viscosity remains low as desired and the solutions can thus be easily transported and processed.

Examples

The polymerizations were carried out in the absence of air and moisture under argon. The isolation of the polymers from the styrenic solution described in individual examples was carried out only for the purpose of characterizing the polymers obtained. The polymers can of course also be stored in the styrenic solution without insulation and processed further accordingly.

The styrene content in the polymer is determined by means of Η-NMR

Spectroscopy, the determination of the selectivity of the polybutadiene (1, 4-cis, 1, 4-trans and 1,2-content) by means of IR spectroscopy, the determination of the solution viscosity in a 5 wt .-% solution of the polymer in Styrene using an Ubelohde viscometer at 25 ° C, determining the glass transition temperature Tg using DSC and determining the water content using Carl Fischer titration.

The impact strength (a ,,, Izod) was determined at 23 ° C and -40 ° C according to ISO 180/1 U, tensile strength, elongation at break, yield stress and modulus of elasticity according to DIN 53 455 and DIN 53 457. The measured values were taken on injection molded molds at a

Melt temperature of 200 ° C and a mold temperature of 45 ° C measured. The melt volume index (MVI, 220 ° C, 5 kg) was determined according to DIN 53 735.

Examples 1 to 7

catalyst aging

In a 200 ml Schlenk flask at 25 ° C to 25 ml of a 0.245 molar

Solution of neodymium (ffi) versatat (NDV) in hexane through a septum containing 33 ml of toluene, 6.75 g of butadiene, 31.9 ml of di-iso-butylaluminium hydride (DIB AH) and 4 ml of one 1 molar ethyl aluminum sesquichloride (EASC) solution added, with stirring

2 hours at 50 ° C and used for the polymerization.

polymerization

The polymerization was carried out in a 40-1 steel reactor with anchor stirrer (100 rpm). At room temperature, a 1.4 molar solution of DIB AH in hexane was added to a solution of butadiene in styrene as a scavenger, the temperature of the reaction solution was raised to 35 ° C. in the course of 10 min and the appropriate amount of catalyst solution was added. The reaction temperature was kept at 35 ° C. during the polymerization. After the reaction time had elapsed, the polymer solution was transferred to a second reactor (80-1 reactor. Anchor stirrer, 50 rpm) within 5 minutes and the polymerization was stopped by adding 345 g of acetylacetone with 30.4 g of Irganox 1076 and 27 g of Irgafos TNPP. To remove unreacted butadiene, the internal reactor pressure was raised to 50 ° C. within 1 h

200 mbar and reduced to 100 mbar within 2 hours.

The batch sizes, reaction conditions and the properties of the polymer obtained are given in Table 1.

Table 1:

Example 8

Semi-continuous ABS polymerisation:

1 200 parts by weight of the rubber solution from Example 3 together with

1 200 parts by weight of the rubber solution from Example 4, 1 200 parts by weight of the rubber solution from Example 5, 1 308 parts by weight of styrene, 4.8 parts by weight of water and 48 parts by weight of silica gel (Aldrich) mixed and filtered at a temperature of 50 ° C and a pressure of 2 bar over a 30 micron filter cloth, which was coated with a layer of another 48 parts by weight of silica gel (Aldrich).

4,355 parts by weight of the rubber solution obtained after filtration are mixed with 7.69 parts by weight of octyl p-2,5-di-tert-butylphenol-propionate (IRGANOX 1076®, Ciba Geigy, Switzerland) . Parts of Irgafos® TNPP (Ciba Geigy, Switzerland), 3 317 parts by weight of styrene and 2 536 parts by weight of acrylonitrile into one

Polybutadiene stock solution mixed.

The solution is applied at a rate of 0.686 kg / h in the first, with an anchor stirrer at 80 rpm. stirred reactor added. The reaction temperature is kept at 85 ° C under atmospheric pressure. At the same time, 0.7 g of tert-butyl peivalate are metered in as a 0.6 percent solution in methyl ethyl ketone per hour. The level is kept at 1,387 kg by discharging the polymerisation syrup through a floor drain (mean residence time 1.75 h). After three average residence times, the solids content is 30% by weight, corresponding to a conversion of 30%, based on styrene and acrylonitrile. The operating state is after the phase reversal, the flow behavior of the reaction mixture is more viscous and elastic than in Example 4. No speck formation is observed.

After 31 hours of continuous driving, the entry and exit flows are switched off. In a mixed batch reactor 1,400 g of syrup from the first

Reaction stage with 5.51 g of dimeric α-methylstyrene and 150 g of methyl ethyl ketone Heated to 85 ° C. A solution of 200 g of methyl ethyl ketone and 1.43 g of t-butyl peivalate is then metered in uniformly within 2 hours. After the end of the metering, the mixture is stirred for a further 4 h at 85 ° C. and then cooled. A solution of 100 g of methyl ethyl ketone, 0.1 g of 2,5-di-tert-butylphenol, 1.2 g of p-2,5-di-tert-butylphenol-propionic acid octyl ester (IRGANOX

1076 ^® , Ciba Geigy, Switzerland) and 8.67 g of paraffin oil. 1 867 g of an ABS solution with 36.0% solids (52.3% conversion) are obtained.

The reaction mixture is evaporated on a 32 mm laboratory twin-shaft co-rotating screw.

An ABS with 14.3% by weight of polybutadiene and an Izod impact strength of 28.9 kJ / m ^{2 is obtained} . Thrust module G '(corr) 1050 MPa, and glass transition temperatures -111 ° C for the rubber phase and 104 ° C for the SAN phase.

Example 9 -10

Production of HIPS molding compounds:

The rubber solution was diluted to 6% dye by adding styrene (stabilized). After adding 0.5 parts of Vulkanox HR ^® and 0.2 parts of α-methylstyrene dimers, 1200 g of this solution were flushed with N ₂ in a 2 1 glass autoclave with a spiral stirrer for 15 minutes. The mixture was heated to 120 ° C. in the course of 1 hour and stirred at this temperature for 4.5 hours (80 rpm). The highly viscous solution obtained was filled into pressure-resistant aluminum molds and polymerized according to the following time / temperature program:

2.5 h at 125 ° C

1.5 h at 135 ° C

1.5 h at 145 ° C l, 5 h at l65 ° C

2.5 h at 225 ° C After cooling, the polymer was comminuted and degassed in vacuo at 100 ° C. for 20 hours. For testing, the samples were sprayed on an injection molding machine. The mechanical values were determined on standard small bars.

Example 9: The one from Example 6 was used as the rubber solution. Example 10: The one from Example 7 was used as the rubber solution

Results

Comparative Examples 11 and 12

catalyst aging

In a 200 ml Schlenk flask at 25 ° C to 50 ml of a 0.245 molar solution of neodymium (III) versatat (NDV) in hexane through a septum, 66 ml of toluene, 13.5 g of butadiene, 63.8 ml of a 5.63 added molar solution of DIBAH and 8 ml of a 1 molar EASC solution, heated to 50 ° C. for 2 hours with stirring and used for the polymerization. polymerization

The polymerization was carried out in a 40 1 steel reactor with anchor stirrer (100 rpm). The room temperature was added to a solution of butadiene in styrene as a scavenger, a solution of DIBAH in hexane, the reaction solution was heated to 35 ° C. in the course of 10 minutes and the appropriate amount of catalyst solution was added. During the polymerization, the reaction temperature was kept at 35 ° C. After the reaction time had expired, the polymer solution was transferred to a second reactor (80 l reactor, anchor stirrer, 50 rpm) within 5 min and the polymerization was stopped by adding 345 g of methyl ethyl ketone with 30.4 g of Irganox 1076 and 27 g of Irgafos TNPP. To remove λ on unreacted butadiene, the internal reactor pressure at 50 ° C. was reduced to 200 mbar within 1 h and to 100 mbar within 2 h.

The batch sizes, reaction conditions and the properties of the obtained

Polymers are given in Table 2.

Table 2 (Comparative Examples 1 1 and 12)

Table 2 (continued)

Comparative Example 13

Semi-continuous ABS polymerisation

A cascade consisting of a continuously operated mixed reactor and a batch-operated mixed reactor is used. The fill level in the first stirred tank is 0.66 kg and 1.52 kg in the batch reactor.

2,530 parts by weight of the rubber solution from Example 11 are mixed together with 4,390 parts by weight of styrene and 2,255 parts by weight of acrylonitrile to form a polybutadiene stock solution.

The stock solution is added at a rate of 0.686 kg / h in the first reactor, which is stirred with an anchor stirrer at 80 rpm. The reaction temperature is kept at 85 ° C under atmospheric pressure. At the same time, 0.68 g of tert-butyl perneodecanoate as a 0.6 percent solution in methyl ethyl added ketone. The level is kept at 1,387 kg by discharging the polymerization syrup through a floor drain (mean residence time 1.75 h). After three average residence times, the solids content is 27% by weight, corresponding to a conversion of 27%, based on styrene and acrylonitrile. The operating state is after the phase reversal.

After about 15 hours of running time, a few small, white specks are visible in the reaction mixture, some of which are deposited on the stirrer. The number of specks increases steadily over time. After about 30 hours, the reactor discharge is blocked by the specks and must be cleared. The experiment is terminated after a run time of 34 hours.

Claims

Patentansprtiche

1. A process for the polymerization of conjugated diolefins (dienes), characterized in that the polymerization of the diolefins in the presence of catalysts consisting of

a) at least one compound of the rare earth metals,

b) at least one organoaluminum compound

c) optionally at least one modifier

and in the presence of vinyl aromatic compounds at temperatures from -30 to + 100 ° C, the molar ratio of components (a) :( b) :( c) in the range from 1: 1 to 1000: 0.1 to 10, component (a) of the catalyst in amounts of 1 μmol to 10 mmol, based on 100 g of the conjugated diolefins used, and the aromatic vinyl compound in amounts of 50 parts by weight to 300 parts by weight per 100 parts by weight of the conjugated diolefin used and the conversion of the diolefin used is less than 50 mol%.

2. The method according to claim 1, characterized in that the conversion of diolefin used is 10 to 45 mol%.

3. The method according to claim 1, characterized in that the conversion of diolefin used is 20 to 40 mol%.

4. The method according to claims 1 to 3, characterized in that the conjugated diolefms selected from the group consisting of 1,3-butadiene, 1,3-isoprene, 2,3-dimethyl butadiene, 2,4-hexadiene, 1 , 3-pentadiene and / or 2-methyl-l, 3-pentadiene or mixtures thereof. Process according to claims 1 to 4, characterized in that the compounds of the rare earth metals are their alcoholates, phosphonates, phosphinates, phosphates and carboxylates and the complex compounds of the rare earth metals with diketones and / or the addition compounds of the

Halides of rare earth metals with an oxygen or nitrogen donor compound can be selected.

Method according to claims 1 to 5, characterized in that component a) is selected from neodymium versatate, neodymium octanate or neodymium naphthenate or mixtures thereof.

Process according to Claims 1 to 6, characterized in that organoaluminium compounds with metals selected from the group Ha, Ilb and Illb of the periodic table are used as component (b).

Process according to claims 1 to 7, characterized in that the modifiers (component c) are selected from the group of organic halogen compounds, halogenated inorganic or organometallic compounds from groups Illb, IVb and Vb of the Periodic Table of the Elements.

Process according to claims 1 to 8, characterized in that the aromatic vinyl compounds are selected from the group consisting of styrene, α-methylstyrene, α-methylstyrene dimer, p-methylstyrene, divinylbenzene, alkylstyrenes with 2 to 6 carbon atoms in the Alkyl radical or mixtures thereof.

Use according to claims 1 to 9 obtainable conjugated dienes for the production of rubber-modified thermoplastic molding compositions. 1

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Process for the production of rubber-modified thermoplastic molding compositions, characterized in that the polymerization of a vinyl aromatic monomer or a vinyl aromatic monomer and an ethylenically unsaturated nitrile monomer in the presence of a rubber dissolved in vinyl aromatic monomer, which can be obtained by polymerizing a diolefin according to claims 1 to 9 , is carried out.