DE19500811A1 - Prepn. of polymers of vinyl:aromatic cpds. using catalyst system - Google Patents

Abstract

Polymers of vinylaromatic cpds. are prepd. at 0-150 deg C, in presence of a catalyst system comprising (A) at least 2 different metallocene complexes and (B) a cpd. forming metallocenium ions. Pref. the aromatic cpds. have formula (I) (where R<1> = H (pref.) or 1-4C alkyl; R<2>-R<6> = H (pref.), 1-12C (1-4C) alkyl (pref.), or halogen (pref. Cl), or 2 adjacent gps. together form a 4-15C (4-12C) cyclic gp., or Ph, biphenyl, naphthalene or anthracene). The components are metallocene complexes formula (II) (where R<7>-R<11> = H, 1-10C alkyl, 5-7C cycloalkyl (opt. carrying 1-6C alkyl gps. as substits.), 6-15C aryl or arylalkyl, or 2 adjacent gps. form together 4-15C cyclic gps., or Si(R<12>)3; R<12> = 1-10C alkyl, 6-15C aryl or 3-10C cycloalkyl; M = metal or 3rd-6th sub-gps. or of the lanthanide series (pref. metal of 4th sub-gp.); Z<1>-Z<5> = H, halogen (Pref.), 1-10C alkyl (pref.), 1-10C alkoxy (pref.), 6-15C aryl or 1-15C aryloxy; z1-z5 = 0-5; z1+z2+z3+z4+z4+z5 = valency of (M - 1)). (B) The components are open-chain or cyclic alumoxan cpds. of formulae (R<13>)(R<13>)Al-(O-Al(R<13>))mR<13> (III) or (IV) (where R<13> = 1-4C alkyl; m = 5-30). The polymers are used to produce mouldings (claimed). Use is esp. in electrical and high temp. resistant applications. A simple process gives syndiotactic polymers with wide distribution of mol.wt. The polymers have mol.wt. 10000-10000000 (50000-1000000) and Mw/Mn of 5-100.

Description

The present invention relates to processes for the production of Polymers of vinyl aromatic compounds at temperatures in the range from 0 to 150 ° C in the presence of catalyst systems.

Furthermore, the present invention relates to the use of here available polymers for the production of mold bodies.

Polymers of vinyl aromatic compounds, in particular Polystyrenes are found in many due to their property profile Areas of use, for example as packaging materials or as insulating coatings for metals or plastics, especially in electrical applications.

One method of making isotactic polystyrene is in GB-A 826 021. Isotactic polystyrene kri stalled so slowly that it was not injection molded can be processed.

Process for the production of syndiotactic polystyrene by Implementation of styrene in the presence of a metallocene complex and of a cocatalyst are described, for example, in EP-A 535 582 and EP-A 584 646. Syndiotactic polystyrene exhibits high chemical resistance, high rigidity, good dimensions stability and good dielectric properties. In the However, the procedures described lead to Polymers with a narrow molecular weight distribution.

For some applications, e.g. housings for motors, elec trical housing, large covers such as hoods or Door leaves, or plugs as well as cable jackets are however syndiotactic polymers of vinyl aromatic compounds with a broad molecular weight distribution is an advantage.

Such polymers are described in EP-A 210 615, however the processes for their production are technically complex and moreover, very broad molecular weight distributions are only through Mixing individual syndiotactic polymers with narrow molecules Lar weight distribution available.

The present invention was therefore based on the object, new Process for the preparation of vinyl aromatic polymers To provide connections that meet the named parts do not show the particularly technically inexpensive are and to syndiotactic polymers with a broad molecular weight lead weight distribution.

Accordingly, processes for the preparation of polymers of vinyl aromatic compounds at temperatures in the range of 0 up to 150 ° C in the presence of catalyst systems, where as Catalyst systems are used as active Be components

• A) at least two different metallocene complexes and
• B) contain a metallocenium ion-forming compound.

Furthermore, the use of the polymers available here sate found for the production of moldings.

Verbin are particularly suitable as vinyl aromatic compounds of general formula I

in which the substituents have the following meaning:
R¹ is hydrogen or C₁- to C₄-alkyl, R² to R⁶ independently of one another hydrogen, C₁- to C₁₂-alkyl, C₆- to C₁₈-aryl, halogen or two adjacent radicals together represent groups of 4 to 15 carbon atoms.

Vinylaromatic compounds of the formula I are preferably used, in which
R¹ is hydrogen
and
R² to R⁶ represent hydrogen, C₁- to C₄-alkyl, chlorine, phenyl, biphenyl, naphthalene or anthracene or where two adjacent radicals together represent groups of 4 to 12 carbon atoms, so that there are compounds of the general formula I, for example Naphthalene derivatives or anthracene derivatives result.

Examples of such preferred compounds are:
Styrene, p-methylstyrene, p-chlorostyrene, 2,4-dimethylstyrene, 4-Vi nylbiphenyl, vinylnaphthalene or vinylanthracene.

Mixtures of different vinyl aromatic can also be used Connections are used, but preferably only one vinyl aromatic compound used.

Particularly preferred vinyl aromatic compounds are styrene and p-methylstyrene.

The production of vinyl aromatic compounds in general NEN Formula I is known per se and for example in hatchet stone 5, 367, 474, 485.

In the processes according to the invention, component A) is used preferably two different general metallocene complexes NEN formula II

in which the substituents and indices have the following meaning:

R⁷ to R¹¹ are hydrogen, C₁- to C₁ Alkyl-alkyl, 5- to 7-membered cycloalkyl, which in turn can carry C₁- to C₆-alkyl groups as substituents, C₆- to C₁₅-aryl or aryl alkyl and optionally also two adjacent radicals together can represent cyclic groups having 4 to 15 carbon atoms, or Si (R¹²) ₃,
with R¹² C₁ to C₁₀ alkyl, C₆ to C₁₅ aryl or C₃ to C₁₀ cycloalkyl,
M a metal of III. to VI. Subgroup of the periodic table of elements or a metal of the lanthanide series
Z¹ to Z⁵hydrogen, halogen, C₁- to C₁₀-alkyl, C₆- to C₁₅-aryl, C₁- to C₁₀-alkoxy or C₁- to C₁₅-aryloxy and
z₁ to z₅ 0, 1, 2, 3, 4 or 5, where the sum z₁ + z₂ + z₃ + z₄ + z₅ corresponds to the valency of M minus the number 1,
used.

Particularly preferred metallocene complexes of the general formula II are those in which
M stands for a metal of subgroup IV of the Periodic Table of the Elements, in particular for titanium
and
Z¹ to Z⁵ are C₁ to C₁₀ alkyl, C₁ to C₁₀ alkoxy or halogen.

Examples of such preferred metallocene complexes are:
Pentamethylcyclopentadienyltitanium trichloride, pentamethylcyclopentadienyltitanium trimethyl and pentamethylcyclopentadienyltitanium trimethylate.

Metallocene complexes such as those in EP-A 584 646 can also be used described, used.

Mixtures of two among have been found to be particularly suitable different metallocene complexes, but it can also Mixtures of up to 5 different metallocene complexes be used.

A mixture of pentamethylcyclopenta is particularly preferred dienyltrimethyl and pentamethylcyclopentadienyl trimethylate puts.

The synthesis of such complex compounds can be per se Known methods take place, the implementation of the corresponding substituted, cyclic hydrocarbon anions with  Halides of titanium, zirconium, hafnium, vanadium, niobium or Tantalum is preferred.

Examples of corresponding manufacturing processes include. a. in the Journal of Organometallic Chemistry, 369 (1989), 359-370 wrote.

In the process according to the invention for the production of polymers Sates of vinyl aromatic compounds are used as component B) Metallocenium ion-forming compounds used.

Open-chain or cyclic, for example, are suitable Alumoxane compounds of the general formula III or IV

where R¹³ is a C₁ to C₄ alkyl group, preferably methyl or ethyl group and m for an integer from 5 to 30 before trains 10 to 25 stands.

These oligomeric alumoxane compounds are prepared usually by reacting a solution of trialkyl aluminum with water and is u. a. in EP-A 284 708 and US-A 4,794,096.

As a rule, the oligomeric alumoxane obtained in this way compounds as mixtures of different lengths, both more linear as well as cyclic chain molecules, so that m is the mean can be seen. The alumoxane compounds can also be mixed with other metal alkyls, preferably with aluminum alkyls gene.  

Other suitable compounds forming metallocenium ions are especially strong, neutral Lewis acids, ionic compounds with Lewis Acidic Cations and Ionic Compounds with Brönsted Acids as a cation.

Compounds of generality are strong, neutral Lewis acids formula V

M¹X¹X²X³ (V)

preferred in the
M¹ is an element of III. Main group of the periodic table means, in particular B, Al or Ga, preferably B,
X¹, X² and X³ for hydrogen, C₁ to C₁₀ alkyl, C₆ to C₁₅ aryl, alkylaryl, arylalkyl, haloalkyl or haloaryl, each with 1 to 10 C atoms in the alkyl radical and 6 to 20 C atoms in the aryl radical or fluorine , Chlorine, bromine or iodine, especially for halogen aryls, preferably for pentafluorophenyl.

Compounds of the general formula V are particularly preferred, in which X¹, X² and X³ are the same, preferably tris (pentafluor phenyl) borane. These compounds and methods for their manufacture position are known per se and for example in the WO 93/3067.

As are ionic compounds with Lewis acid cations Compounds of the general formula VI

[(Aa +) Q₁Q₂. . . Qz] ^dt VI

suitable in which
A an element of I. to VI. Main group or the I. to VIII. Subgroup of the periodic table means
Q₁ to Q _z for single negatively charged radicals such as C₁- to C₂₈-alkyl, C₆- to C₁₅-aryl, alkylaryl, arylalkyl, haloalkyl, haloaryl, each with 6 to 20 C-atoms in the aryl and 1 to 28 C atoms in the alkyl radical, C₁ to C₁₀ cycloalkyl, which may optionally be substituted by C₁ to C₁₀ alkyl groups, halogen, C₁ to C₂₈ alkoxy, C₆ to C₁₅ aryloxy, silyl or mercaptyl groups
a represents integers from 1 to 6,
z for integers from 0 to 5
d corresponds to the difference az, but d is greater than or equal to 1.

Carbonium cations, oxonium cations and Sulfonium cations and cationic transition metal complexes. Ins special are the triphenylmethyl cation, the silver cation and to name the 1,1'-dimethylferrocenyl cation.

They preferably have non-coordinating counterions, ins special boron compounds, such as those in WO 91/09882 be mentioned, preferably tetrakis (pentafluorophenyl) borate.

Ionic compounds with Bronsted acids as cations and before counterions which are also non-coordinating are in the WO 93/3067 called, preferred cation is the N, N-dimethyl anilinium.

The polymerization of the vinyl aromatic compounds can be carried out in Solution, in bulk, in suspension or in the gas phase. It is preferred to work in solution, with the solvent being for example aromatic hydrocarbons such as benzene, toluene, Ethylbenzene or xylenes, and ethers such as diethyl ether, dibutyl ether, ethylene glycol dimethyl ether or tetrahydrofuran, or also aliphatic hydrocarbons such as propane, n-butane, isobutane or pentanes, and mixtures of the various solvents can be used, or in bulk.

The polymerization conditions are not critical per se and are suitable are temperatures in the range from 0 to 150 ° C., preferably from 10 to 100 ° C, pressures from 0.1 to 100 bar, preferably from 1 to 5 bar and polymerization times from 0.1 to 24 hours, preferred from 0.5 to 6 hours.

The metallocene complexes are preferably inserted without support sets, but they can also be used as supports.

Suitable carrier materials are, for example, silica gels, be preferably those of the formula SiO₂ · aAl₂O₃, where a is a number in Range is from 0 to 2, preferably 0 to 0.5; so in the we considerable aluminosilicates or silicon dioxide. Preferably point the carriers have a particle diameter in the range from 1 to 200 μm  on, in particular 30 to 80 microns. Such products are on the market available, e.g. B. as silica gel 332 from Grace.

Other thugs are u. a. finely divided polyolefins, for example finely divided polypropylene or polyethylene, but also poly ethylene glycol, polybutylene terephthalate, polyethylene terephthalate, Polyvinyl alcohol, polystyrene, polybutadiene, polycarbonates or their copolymers.

Aluminum alkyls can also be used in the polymerization be used. Here are trimethyl aluminum, triethyl aluminum, tri-iso-propyl aluminum, tri-n-propyl aluminum, tri isobutyl aluminum and tri-n-butyl aluminum are particularly suitable, in particular, however, triisobutyl aluminum.

The addition of such aluminum alkyls is necessary when using strong neutral Lewis acids, ionic compounds with Lewis acidic cations and ionic compounds with Bronsted acids as cations, as compounds forming metallocenium ions suitable.

It has proven to be advantageous if the molar ratio of the vinyl aromatic compound to the compound forming metallocenium ions is in the range from 10²: 1 to 10⁷: 1, preferably in the range from 10³: 1 to 10⁶: 1. The molar ratio of metallocenium ion-forming compound to the total molar amount of metallocene complexes is preferably in the range from 10 ^-2 : 1 to 10⁷: 1, in particular in the range from 10²: 1 to 10⁵: 1.

In the preferred case that two different metallocene complexes are used, the molar ratio of one metal ocene complex to the other metallocene complex is preferably in the range from 10 ^-3 : 1 to 10³: 1, in particular in the range from 10 ^-2 : 1 to 10²: 1. If three or more metallocene complexes are used, the composition can vary so much that a metallocene complex is present up to a 1000-fold molar excess compared to the next most common metallocene complex. However, at most a 100-fold molar excess is preferred.

If an aluminum alkyl is used, it has a molar ratio of aluminum alkyl to the total amount of metallocene complexes of 10,000: 1 to 10: 1, preferably from 1000: 1 to 100: 1 proven otherwise.

This is preferably the case with the method according to the invention before that the vinyl aromatic compound, optionally with added a solvent, submitted to temperatures in the loading  heated from 40 to 80 ° C and either the open chain or cyclic alumoxane compound or the trialkyl aluminum and the strong, neutral Lewis acid, the ionic compound with Lewis acidic cation or the ionic compound with a Bronsted Add acid as a cation. Then you give the Mixture of the two metallocene complexes, optionally with one Solvent. But you can also use the metallocene complexes mix beforehand with the compound forming the metallocenium ion and add this mixture to the reactor. Then preferably over polymerized for a period of 45 to 90 minutes and the poly merisation terminated by adding methanol. The received Polymer is preferably washed with methanol and at 40 dried to 100 ° C.

The process according to the invention is distinguished by the fact that it is technically inexpensive, the resulting polymers are syndiotactic and have a broad molecular weight distribution M _w : M _n of preferably 5 to 100 and are particularly suitable for the use of molding compositions in electrical or high-temperature-resistant applications . The molar masses of the polymers prepared by the process according to the invention are in the range from 10,000 to 10,000,000 g / mol, preferably from 50,000 to 1,000,000 g / mol.

Examples Manufacture of syndiotactic polystyrene example 1

2.0 mol of styrene (208.3 g) were placed in a round bottom flask inertized with nitrogen, the mixture (which mixture?) Was heated to 70 ° C. and mixed with 1.1 ml of methylaluminoxane (MAO) from Witco (1.53 molar) in toluene). Subsequently, the mixture was mixed with 23.04 mg (8.34 · 10 ^-5 mol) of penta methylcyclopentadienyltrimethylate and 19.03 mg (8.34 · 10 ^-5 mol) of pentamethylcyclopentadienyltrimethyl. Now a further 9.8 ml of the above-mentioned MAO were added. The internal temperature was adjusted to 70 ° C and allowed to polymerize for 1 hour. The polymerization was then terminated by adding methanol. The polymer obtained was washed with methanol and dried at 50 ° C. in vacuo. The molecular weight distribution was determined by high-temperature GPC (gel permeation chromatography) with 1,2,4-trichlorobenzene as the solvent at 135 ° C. The calibration was carried out using narrowly distributed polystyrene standards. The molar mass was M _w = 81 833 with a distribution width of M _w / M _n = 28.3. The syndiotactic fraction determined by 13 C-NMR was <96%.

Example 2

0.6 mol of styrene (62.5 g) in 203 ml of purified ethylbenzene were placed in a round bottom flask inertized with nitrogen, the mixture was heated to 50 ° C. and triisobutylaluminum (2.84 ml; 0.88 molar in toluene = 2. 5 mmol) (Is the information correct? Cf. Vglsbsp. 2 of your draft). Now a further 83.0 mg of tris (pentafluorophenyl) borane dissolved in 5.0 ml of ethylbenzene were added and then the mixture was mixed with a catalyst mixture of 22.4 mg (8.11 · 10 ^-5 mol) of pentamethylcyclopentadienyltri methylate and 18.5 mg (8.11 · 10 ^-5 mol) of pentamethylcyclopenta dienyltrimethyl dissolved in 5 ml of ethylbenzene. The internal temperature was adjusted to 50 ° C and allowed to polymerize for 1 hour. The polymerization was then terminated by adding methanol. The polymer obtained was washed with methanol and dried at 50 ° C. in vacuo. The molar mass distribution was determined by high temperature GPC. The molecular weight was determined by GPC in 1,3,5-trichlorobenzene as solvent at 120 ° C. and was M _w = 104,200 at M _w / M _n = 34.7. The syndiotactic fraction determined by 13 C-NMR was <96%.

Comparative Example 1

The procedure was as in Example 1, but instead of the mixture of 23.04 mg pentamethylcyclopentadienyltrimethylate and 19.03 mg pentamethylcyclopentadienyltrimethyl, 46.04 mg (16.67 · 10 ^-5 mol) of pentamethylcyclopentadienyltrimethylate was used.

The molar mass was M _w = 240 200 with a distribution width of M _w / M _n = 1.41. The syndiotactic fraction determined by 13 C-NMR was <96%.

Comparative Example 2

0.6 mol of styrene (62.5 g) in 203 ml of purified ethylbenzene were placed in a round bottom flask inertized with nitrogen, the mixture was heated to 50 ° C. and triisobutylaluminum (4.1 ml; 0.61 molar in toluene = 2. 5 inmol). A further 128.0 mg of tris (pentafluorophenyl) borane dissolved in 3.0 ml of ethylbenzene were then added, and then 57.1 mg (25.0 × 10 ^-4 mol) of pentamethylcyclopentadienyltrimethyl dissolved in 3 ml of ethylbenzene were added. The internal temperature was adjusted to 50 ° C and allowed to polymerize for 1 hour. The polymerization was then terminated by adding methanol. The polymer obtained was washed with methanol and dried at 50 ° C. in vacuo. The molecular weight distribution was determined by high-temperature GPC. The molecular weight was determined by GPC in 1,3,5-trichlorobenzene as solvent at 120 ° C. and was M _w = 182,500 at M _w / M _n = 1.83. The syndiotactic fraction determined by 13 C-NMR was <96%.

Claims (8)

1. Process for the preparation of polymers of vinyl aromatic compounds at temperatures in the range from 0 to 150 ° C. in the presence of catalyst systems, characterized in that catalyst systems used are those which act as active constituents

• A) at least two different metallocene complexes and
• B) contain a metallocenium ion-forming compound.

2. The method according to claim 1, characterized in that compounds of the general formula I as vinyl aromatic compounds in which the substituents have the following meaning:
R¹ is hydrogen or C₁- to C₄-alkyl, R² to R⁶ independently of one another hydrogen, C₁- to C₁₂- alkyl, C₆- to C₁₈-aryl, halogen or where two adjacent radicals together represent groups of 4 to 15 carbon atoms
be used. 3. The method according to claim 2, characterized in that those are used as vinyl aromatic compounds of the general formula I in which
R¹ is hydrogen
and
R² to R⁶ represent hydrogen, C₁- to C₄-alkyl, chlorine, phenyl, biphenyl, naphthalene or anthracene or where two adjacent radicals together represent groups containing 4 to 12 carbon atoms. 4. Process according to claims 1 to 3, characterized in that at least two different metallocene complexes of the general formula II as component A) in which the substituents and indices have the following meaning:
R⁷ to R¹¹ are hydrogen, C₁- to C₁₀-alkyl, 5- to 7-membered cycloalkyl, which in turn can carry C₁- to C₆-alkyl groups as substituents, C₆- to C₁₅-aryl or arylalkyl and optionally also two adjacent radicals together for 4 to 15 carbon atoms can be cyclic groups, or Si (R¹²) ₃,
with R¹² C₁ to C₁₀ alkyl, C₆ to C₁₅ aryl or C₃ to C₁₀ cycloalkyl,
M a metal of III. to VI. Subgroup of the periodic table of the elements or a metal of the Lan thaniden series
Z¹ to Z⁵ are hydrogen, halogen, C₁ to C₁₀ alkyl, C₆ to C₁₅ aryl, C₁ to C₁₀ alkoxy or C₁ to C₁₅ aryl oxy
and
z₁ to z₅ 0, 1, 2, 3, 4 or 5, where the sum z₁ + z₂ + z₃ + z₄ + z₅ corresponds to the valency of M minus the number 1,
be used. 5. The method according to claim 4, characterized in that metallocene complexes of the general formula II are used as component A) in which
M stands for a metal of subgroup IV of the Periodic Table of the Elements and
Z¹ to Z⁵ C₁ to C₁₀ alkyl, C₁ to C₁₀ alkoxy or halogen
mean. 6. The method according to claims 1 to 5, characterized in that as component B) open-chain or cyclic alumoxane compounds of the general formula III or IV wherein R¹³ is a C₁ to C₄ alkyl group and m is an integer from 5 to 30,
be used. 7. The method according to claims 1 to 5, characterized records that as component B) a coordination complex ver binding, selected from the group of strong, neutral Lewis acids, the ionic compounds with Lewis acids Cations and the ionic compounds with Bronsted acids is used as cations. 8. Use of the produced according to claims 1 to 7 Polymers of vinyl aromatic compounds position of shaped bodies.