DE19506556A1 - Prepn. of vinyl]-aromatic polymers, giving syndiotactic polymers for use in prodn. of mouldings - Google Patents

Abstract

Polymers of vinylaromatic cpds. are prepd. at 0-150 deg.C, in presence of catalysts contg. as active components (A) cpds. of formula XM(Z<1>)z1(Z<2>)z2(Z<3>)z3 (I) and (B) (i) open-chain or cyclic alumoxane cpds. of formula (III) or (IV), or (ii) cpds. forming metallocene ions, comprising strong neutral Lewis acids, ionic cpds. with Lewis acid cations or ionic cpds. with a Bronsted acid as cation. In the formulae, X = 1-10C alkyl or alkoxy, 5-7 member cycloalkyl, 6-15C aryl or formula (II) (where R<1>-R<5> = H, 1-10C alkyl (opt. with 1-5 halogen substits.), 5-7 member cycloalkyl (opt. with 1-6C alkyl substits.), 6-15C aryl or arylalkyl where 2 vicinal gps. may together form 4-15C cyclic gps., or halogen, 1-10C alkoxy, NR<6>R<7> or Si(R<6>)3 (where R<6>, R<7> = H, 1-10C alkyl, 6-15C aryl or 3-10C cycloalkyl); M = metal of the IInd - VIIIth Sub-gps.; Z<1>-Z<3> = polymers of vinylaromatic cpds., dienes, and/or acrylates; z1, z2, z3 = 0-3; z1 + z2 + z3 = 1-3; R<8> = 1-4C alkyl; m = 5-30.

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, however, that there was insufficient spraying cast 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 methods described have the Disadvantage that the catalysts are not immediately active.

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 in which the catalysts are active immediately and look good can be separated from the resulting polymer and the syndio tactical polymers.

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) Compounds of the general formula I XM (Z¹) _z₁ (Z²) _z₂ (Z³) _z₃ (I) in which the substituents and indices have the following meanings:
  X is C₁ to C₁₀ alkyl, 5- to 7-membered cycloalkyl, C₁ to C₁₀ alkoxy, C₆ to C₁₅ aryl or compounds of the general formula II with R¹ to R⁵ hydrogen, C₁- to C₁₀-alkyl, which can be substituted 1 to 5 times with Ha, 5- to 7-membered cycloalkyl, which in turn can carry C₁- to C₆-alkyl groups as sub-substituents, C₆- to C₁₅ Aryl or arylalkyl and where appropriate two adjacent radicals can together stand for cyclic groups having 4 to 15 carbon atoms, or halogen, C₁ to C₁₀ alkoxy, NR⁶R⁷ or Si (R⁶) ₃,
  with R⁶ and R⁷ hydrogen, C₁- to C₁₀-alkyl, C₆- to C₁₅-aryl or C₃- to C₁₀-cycloalkyl,
  M is a metal from subgroup II to VIII of the Periodic Table of the Elements
  Z¹ to Z³ polymers of vinyl aromatic compounds, dienes, acrylates or mixtures thereof
  and
  z₁ to z₃ 0, 1, 2 or 3, where 1 is z₁ + z₂ + z₃ 3,
  and
• B) open-chain or cyclic alumoxane compounds of the general formula III or IV where R⁸ is a C₁ to C₄ alkyl group and m is an integer from 5 to 30,

contain.

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

Verbin are particularly suitable as vinyl aromatic compounds of the general formula V

in which the substituents have the following meaning:
R⁹ is hydrogen or C₁ to C₄ alkyl,
R¹⁰ to R¹⁴ independently of one another are hydrogen, C₁- to C₁₂- alkyl, C₆- to C₁₈-aryl, halogen or two adjacent residues together represent 4 to 15 carbon atoms pointing to cyclic groups.

Vinyl aromatic compounds of the formula V are preferably used, in which
R⁹ means hydrogen and
R¹⁰ to R¹⁴ represent hydrogen, C₁- to C₄-alkyl, chlorine or phenyl or where two adjacent radicals together are 4 to 12 carbon atoms having cyclic groups, so that there are compounds of the general formula V, for example naphthalene derivatives or anthra cene derivatives .

Examples of such preferred compounds are:
Styrene, p-methylstyrene, p-chlorostyrene, 2,4-dimethylstyrene, 4-vinylbiphenyl, 2-vinylnaphthalene or 9-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 V is known per se and for example in hatchet stone 5, 367, 474, 485.

In the processes according to the invention, component A) Compounds of the general formula I used. Of these Compounds I are preferred in which X is C₁ to bis C₄-alkyl, especially methyl and ethyl, C₁- to C₄-alkoxy or particularly preferred for compounds of the general formula II

stands.

Of the compounds of general formula II are those preferred, in which R¹ to R⁵ is hydrogen, C₁- to C₄-alkyl, ins special methyl, C₆ to C₁₅ aryl, especially phenyl and Biphenyl, means or where two adjacent radicals together represent cyclic groups having 4 to 15 carbon atoms, at for example, X then stands for indenyl, benzindenyl or fluorenyl, which in turn can be substituted with alkyl radicals.

X particularly preferably represents pentamethylcyclopentadienyl.

In the event that X for compounds of the general formula II stands, the compounds of general formula I represent half sandwich complexes.

The metal M preferably represents elements from IV. To VI. Sub-group of the periodic table, especially for elements the IV. subgroup, ie for titanium, zirconium and hafnium, be preferred for titanium.

Z¹ to Z³ stand for polymers of vinyl aromatic compounds, Serve like butadienes or isoprene, acrylates, preferably with 1 up to 6 carbon atoms in the ester radical, in particular butyl acrylate or their Mixtures so that Z¹ to Z³ then represent copolymers.

Z 1 to Z 3 are preferably vinyl aromatic polymers Compounds of the general formula VI

in which the substituents have the following meaning:
R¹⁵ is hydrogen or C₁ to C₄ alkyl,
R¹⁶ to R²⁰ independently of one another are hydrogen, C₁- to C₁₂-alkyl, C₆- to C₁₈-aryl, halogen or two adjacent radicals together represent 4 to 15 carbon atoms pointing to cyclic groups.

Vinyl aromatic compounds of the formula VI in which
R¹⁵ means hydrogen
and
R¹⁶ to R²⁰ represent hydrogen, C₁- to C₄-alkyl, chlorine or phenyl or where two adjacent radicals together represent 4 to 15 carbon atoms having cyclic groups, so that there are compounds of the general formula VI, for example, naphthalene derivatives or anthra cene derivatives .

Examples of such preferred compounds are also
Styrene, p-methylstyrene, p-chlorostyrene, 2,4-dimethylstyrene, 4-vinylbiphenyl, 2-vinylnaphthalene or 9-vinylanthracene.

Particularly preferred vinyl aromatic compounds of the formula VI are styrene and p-methylstyrene.

Z 1 to Z 3 are preferably polymers of the same compounds, particularly preferably polystyrenes. The molecular weights M _n (number average values) of the respective Z 1 to Z 3 are generally in the range from 500 to 10⁸ g / mol, preferably in the range from 10³ to 10⁶ g / mol.

It has proven particularly suitable if Z 1 to Z 3 poly mers from the same compounds, preferably polystyrenes, and the polymers prepared according to the invention are such are those in which the vinyl aromatic compounds V are the same Compounds are used like those which lead to Z¹ to Z³, also styrene.

A particularly preferred compound of formula I is that where X is pentamethylcyclopentadienyl, M is titanium and Z¹ to Z³ are polystyrenes.  

The number z₁, z₂, z₃ of the respective polymers Z¹, Z², Z³ depends significantly from the metal M. In the preferred case that M is a Is metal of subgroup IV of the Periodic Table of the Elements, the sum z₁ + z₂ + z₃ is preferably 3.

The polymers Z 1 to Z 3 are in the compounds of the formula I. covalently bound to the metal M.

The compounds of general formula I can herge be that the vinyl leading to the polymers Z¹ to Z³ aromatic compounds, dienes, acrylates or mixtures thereof polymerized anionically and then with a transition metal salt of the general formula VII

XMY _y (VII)

with Y fluorine, chlorine, bromine or iodine
and y 1, 2 or 3
be implemented.

The anionic polymerization of vinyl aromatic compounds, Serving, acrylates or their mixtures is known per se and in Maurice Morton, Anionic Polymerization: Principles and Prac tice, Academic Press, 1983. Usually done anionic polymerization by adding alkali metal compounds, for example phenyllithium, sodium methylate, n- Butyllithium or sec-butyllithium to the monomer. To this anionic polymers that are still living then become a transition measurement tall salt of the general formula VII added. From these sal Zen are preferred in which Y is chlorine or bromine, stands especially for chlorine.

Regarding the preferred compounds belonging to the polymers Z¹ lead to Z³ and the substituent X and the metal M in the general formula VII applies to the compounds of the general my Formula I said.

The reaction conditions for the preparation of the compounds of Formula I are not critical in themselves. The reaction temperature generally lies in the range from -75 to 150 ° C, preferably from -10 to 100 ° C.

The molar amount of transition metal salt is preferably 0.001 to 2.0 molar equivalents based on the amount of alkali metal compounds in anionic polymerization.  

It has been found to be suitable if the transition metal salt of the general formula VII dissolved in an inert solvent is. Hydrocarbons such as pentane are suitable as solvents or hexane, benzene, toluene, xylenes, ethers such as diethyl ether or Tetrahydrofuran or mixtures thereof.

In the process according to the invention for the production of polymers Sates of vinyl aromatic compounds are used as component B) open chain or cyclic alumoxane compounds of the general Formula III or IV

wherein R⁸ 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.

The vinyl aromatic polymerization according to the invention Compounds can be in solution, in bulk, in suspension or in the Gas phase. It is preferred to work in solution, whereby as Solvents such as aromatic hydrocarbons such as Benzene, toluene, ethylbenzene or xylenes, and ethers such as diethyl ether, dibutyl ether, ethylene glycol dimethyl ether or tetrahydro  furan, or aliphatic hydrocarbons such as propane, n- Butane, isobutane or pentanes, and mixtures of the different 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 compounds of general formula I are preferably un used carrier, but you can also use carrier will.

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 essential aluminosilicates or silicon dioxide. Preferably the carriers have a particle diameter in the range from 1 to 200 microns, especially 30 to 80 microns. Such products are in the Commercially available, e.g. B. as silica gel 332 from Grace.

Other carriers 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.

It has proven advantageous to use component A) and oligomeric alumoxane compound (component B)) in such amounts use the atomic ratio between aluminum from the oligomeric alumoxane compound and the transition metal from the Compounds of formula I in the range from 10: 1 to 10⁶: 1, ins especially in the range of 10: 1 to 10⁴: 1.

As a solvent for these catalyst systems are more common wise aromatic hydrocarbons used, preferably with 6th up to 20 carbon atoms, in particular xylenes and toluene and their Mixtures.

The method according to the invention is preferably used in this way before that the vinyl aromatic compound, optionally with added a solvent, submitted to temperatures in the loading heated from 40 to 80 ° and the open chain or cyclic Verum alumoxane compound with a solvent if necessary sets, adds. Then you give the connection of the general formula I, optionally with a solvent,  added. Then preferably over a period of 45 to Polymerized for 90 minutes and the polymerization by adding Methanol canceled. The polymer obtained is preferred washed with methanol and dried at 40 to 100 ° C.

The inventive method is characterized in that it It is technically not very expensive that the catalysts are immediately active are and can be easily separated from the resulting polymer, the resulting polymers are syndiotactic and are suitable especially for the use of molding compounds in electrical or high temperature resistant applications. The molecular weights of the after Polymers prepared according to the invention are in the Range from 10,000 to 10,000,000 g / mol, preferably from 50,000 up to 1,000,000 g / mol.

Examples example 1 Production of pentamethylcyclopentadienyl-tris- (polystyryl) - titanate I1

31.25 g were placed in a 500 ml flask under an inert gas atmosphere (0.3 mol) unstabilized styrene dissolved in 200 ml of n-hexane and heated to 60 ° C.

60 mmol of sec-butyllithium were then added to this mixture at 60 ° C. given and polymerized under an inert gas atmosphere for 1 hour.

Then this mixture became 5.0 g (18.22 mmol) of penta methylcyclopentadienyltitanium trichloride added in 125 ml of n-hexane and cooled to 0 ° C. Then it was ge for 12 hours at room temperature stirs. The resulting product was under an inert gas atmosphere from insoluble components separated (glass frit, 4 µm) and am Vacuum concentrated

Example 2 Manufacture of syndiotactic polystyrene

In a round-bottom flask inertized with nitrogen, 0.6 mol of styrene (62.5 g) were placed, heated to 50 ° C. and mixed with 3.0 ml of methyl aluminoxane (MAO) from Witco (1.67 molar in toluene). The mixture was then mixed with 320 mg (16.65 · 10 ^-5 mol) and I1. Now a further 26.9 ml of the above-mentioned MAO 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 M _w (weight average) and the molecular weight distribution were 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 = 42,800 with a distribution width of M _w / M _n = 1.81. The syndiotactic fraction determined by 13 C-NMR was <96%.

Claims (6)

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) Compounds of the general formula I XM (Z¹) _z₁ (Z²) _z₂ (Z³) _z₃ (I) in which the substituents and indices have the following meanings:
  X is C₁ to C₁₀ alkyl, 5- to 7-membered cycloalkyl, C₁ to C₁₀ alkoxy, C₆ to C₁₅ aryl or compounds of the general formula II with R¹ to R⁵ hydrogen, C₁- to C₁₀ alkyl, which can be substituted 1 to 5 times by halogen, 5- to 7-membered cycloalkyl, which in turn can carry C₁ to C₆ alkyl groups as substituents, C₆ to C₁₅ aryl or Arylalkyl and, where appropriate, two adjacent radicals together can represent cyclic groups having 4 to 15 carbon atoms, or halogen, C₁- to C₁₀alkoxy, NR⁶R⁷ or Si (R⁶) ₃,
  with R⁶ and R⁷ hydrogen, C₁- to C₁₀-alkyl, C₆- to C₁₅-aryl or C₃- to C₁₀-cycloalkyl,
  M is a metal from subgroup II to VIII of the periodic table of the elements
  Z¹ to Z³ polymers of vinyl aromatic compounds, dienes, acrylates or their mixtures and
  z₁ to z₃ 0, 1, 2 or 3, where 1 is z₁ + z₂ + z₃ 3,
  and
• B) open-chain or cyclic alumoxane compounds of the general formula III or IV where R⁸ is a C₁ to C₄ alkyl group and m is an integer from 5 to 30,

contain. 2. The method according to claim 1, characterized in that as vinyl aromatic compounds compounds of the general formula V in which the substituents have the following meaning:
R⁹ is hydrogen or C₁ to C₄ alkyl,
R¹⁰ to R¹⁴ independently of one another are hydrogen, C₁- to C₁₂- alkyl, C₆- to C₁₈-aryl, halogen or where two adjacent radicals together represent cyclic groups having 4 to 15 C atoms
be used. 3. Process according to claims 1 to 2, characterized in that those are used as vinyl aromatic compounds of the general formula V in which
R⁹ means hydrogen and
R¹⁰ to R¹⁴ represent hydrogen, C₁- to C₄-alkyl, chlorine or phenyl, or where two adjacent radicals together represent 4 to 12 carbon atoms having cyclic groups. 4. The method according to claims 1 to 3, characterized in that compounds of general formula I are used as component A) in which
X represents compounds of the general formula II,
M is a metal from IV. To VI. Subgroup means
and
Z¹ to Z³ for polymers of vinyl aromatic compounds of the general formula VI in which the substituents have the following meaning:
R¹⁵ is hydrogen or C₁ to C₄ alkyl,
R¹⁶ to R²⁰ independently of one another are hydrogen, C₁- to C₁₂-alkyl, C₆- to C₁₈-aryl, halogen or where two adjacent radicals together represent cyclic groups having 4 to 15 C atoms,
stand. 5. Use of the Po produced according to claims 1 to 4 Lymerisate of vinyl aromatic compounds for the production of moldings.