WO1997010272A1

WO1997010272A1 - Process for producing propene/but-1-ene copolymers

Info

Publication number: WO1997010272A1
Application number: PCT/EP1996/003891
Authority: WO
Inventors: David Fischer; Franz Langhauser; Meinolf Kersting; Roland Hingmann; Günther SCHWEIER
Original assignee: Basf Aktiengesellschaft
Priority date: 1995-09-11
Filing date: 1996-09-04
Publication date: 1997-03-20
Also published as: CN1201468A; EP0850255A1; JPH11512462A; DE19533336A1

Abstract

A process is disclosed for producing propene/but-1-ene copolymers in which the molar ratio between propene and but-1-ene lies in a range from 10,000:1 to 4:1. Polymerisation is continuously carried out at temperatures in a range from 50 to 120 °C. Systems that contain as active components (A) metallocene complexes; (B) a metallocene ion-generating compound; and optionally (C) an aluminium compound, are used as catalyst systems.

Description

Process for the preparation of propene / but-1-ene copolymers

description

The present invention relates to processes for the preparation of propene / but-1-ene copolymers, the molar ratio of propene to but-1-ene being in the range from 10,000: 1 to 4: 1, at temperatures in the range from 50 to 120 ° C continuously polymerized and used as catalyst systems that act as active ingredients

A) Metallocene complexes of the general formula I

in which the substituents have the following meaning:

M titanium, zirconium, hafnium, vanadium, niobium or

Tantalum,

X fluorine, chlorine, bromine, iodine, hydrogen, C -.- to C-. ₀ -A1- kyl, C (, - to -C ₅ -aryl, alkylaryl with 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical,

-OR ¹² or -NR ¹² Rl ³ ,

in which R ¹² and R ^{13 are} C 1 to C 10 alkyl, C 6 to C ₅ aryl, alkylaryl, arylalkyl, fluoroalkyl or fluoroaryl each having 1 to 10 C atoms in the alkyl radical and 6 to 20 C atoms in the aryl radical,

Rl and R ⁷ Ci to Cio alkyl or Cβ to Cι ₅ aryl,

R ² and Rδ are hydrogen, Ci- to Cio-alkyl, 5- to 7-membered cycloalkyl, which in turn can carry a Cι ~ to Cio-alkyl as a substituent, or Si (R ¹⁴ ) ₃ with

R ¹⁴ Ci- to Cio-alkyl or C ₃ - to -CC ₀ cycloalkyl

R ³ to R ⁵ and R ⁹ to R ^{11 are} hydrogen, C 1 to C ₀ alkyl, 5- to 7-membered

Cycloalkyl, which in turn can carry a C ₁ -C 8 -alkyl as a substituent, C ₆ - to Cis-aryl or arylalkyl, where optionally two adjacent radicals together can also represent cyclic groups having 4 to 15 C atoms, or Si (R ¹⁵ ) ₃ with

R ¹⁵ Ci to Cio alkyl, C ₆ to C ^ aryl or C ₃ to

Cio-cycloalkyl,

or where

R ² and R ³ together for 4 to 15 carbon atoms cyclic

Groups stand,

or wherein R ⁸ and R ⁹ together for 4 to 15 C-containing cyclic

Groups stand,

15 R15 R15 _R 15

R6

M ¹ M ¹ M ¹ - M ¹ CR ₂ 17.

_R 16 _R 16 _R 16 _R 16

(15 R15 _R 15 _R 15

0 M ¹ - CC '

R ¹⁶ Rl 6 _R 16 _R 16 - BR ¹⁵ , - AIR ¹⁵ , -Ge-, -Sn-, -0-, -S-, - SO, - S0 ₂ , = NR ¹⁵ , - CO, = PR ¹⁵ or ■ = P (0) R ¹⁵ is, wherein R ¹⁵ , R ¹⁶ and R ^{17 are the} same or different and a hydrogen atom, a halogen atom, a Cι-Cιo-alkyl group, a Cι-Cιo-fluoroalkyl group, a C ₆ -Cιo ~ fluoroaryl group, a Cβ-Cio-aryl group mean a Ci-Cio-alkoxy group, a C ₂ -C ~ alkenyl group, a C ₇ -C ₄ o-arylalkyl group, a Cβ-C ₄ o-arylalkenyl group or a C ₇ -C ₄ o-alkyl aryl group or R ¹⁵ and R ¹⁶ or R ¹⁵ and R ¹⁷ each form a ring with the atoms connecting them, and

M ^{1 is} silicon, germanium or tin

contain,

B) a compound forming metallocenium ions and

C) optionally an aluminum compound of the general formula II

AlR ¹⁸ R ¹⁹ R ²⁰ II

in the

R ¹⁸ to R ^{20 are} fluorine, chlorine, bromine, iodine or C ~ ~ to Ci ₂ ~ alkyl.

Furthermore, the present invention relates to the use of the copolymers thus obtained for the production of films or moldings and to the films and moldings obtainable here.

Binary propene / but-1-ene copolymers have recently received increased interest, for example as sealing layer materials as in AM Chatterjee et al. , Soc. of Plastics Engineers, ANTEC Conf. Proc. S. 1977-1981 (1994). Compared to the ethene / propene copolymers usually used for this application, they are characterized, with the same melting point, by a significantly lower sealing temperature and, at the same time, higher rigidity. Low sealing temperatures, ie low melting points of the polymer, are desirable for the applications mentioned. For this purpose, since the molar melting point reduction caused by the incorporation of but-1 is considerably less than that caused by the incorporation of ethene, very large amounts of but-1-ene (greater than 12 mol%) have to be introduced into the monomer mixture. Due to the onset of condensation of but-l-ene, this is only useful in gas phase processes, for example. absolutely possible and usually requires a lowering of the propene partial pressure. The catalyst productivity and the economy of the process suffer equally from this. Binary propene / but-1-ene copolymers with low melting points and a relatively low comonomer content are described in US Pat

EP-A 318 049. These copolymers are produced with homogeneous zirconocene catalysts in solution polymerization, at polymerization temperatures of 0 ° C. It is not possible to transfer this method of manufacture to technical conditions.

The object of the present invention was therefore to remedy the disadvantages mentioned, in particular to keep the amount of but-l-ene to be used as low as possible and to provide a process which can be carried out on an industrial scale.

Accordingly, the process defined at the outset was found.

Furthermore, the use of the copolymers obtained in this way for the production of films and moldings and the films and moldings obtainable here were found.

The molar ratio of the monomers propene and but-1-ene used is in the range from 10,000: 1 to 4: 1, preferably 50: 1 to 5: 1, in particular 25: 1 to 7: 1 (propene: but-1-ene ). Small amounts of other monomers can also be present, but preferably not more than 1 mol%, based on the amount of propene used. Ethylene or other olefins are preferred here, preferably hex-1-ene, oct-1-ene and dec-1-ene.

The process according to the invention is carried out continuously at temperatures in the range from 50 to 120 ° C., preferably from 60 to 100 ° C.

Of the metallocene complexes of the general formula I used in the process according to the invention, preference is given to those in which

M stands for zirconium or hafnium,

X represents chlorine or C 1 -C ₄ -alkyl, in particular chlorine or methyl,

R ¹ and R ⁷ for -C ~ to C ₄ alkyl, in particular methyl or ethyl, or phenyl, R ² and R ^{θ are} C 1 -C ₄ -alkyl, in particular methyl, ethyl, n-propyl, isopropyl, n-butyl or tert-butyl,

R ³ to R ⁵ and R ⁹ to R ¹¹ for hydrogen, Ci to C ₄ alkyl, in particular methyl, ethyl, n-propyl, isopropyl, n-butyl or tert-butyl, Ce, - to -C ₂ aryl , in particular phenyl or where two adjacent radicals together represent 4 to 15 carbon atoms, in particular 8 to 12 carbon atoms, cyclic groups,

or where

R ² and R ³ together represent 4 to 15 carbon atoms, in particular cyclic groups containing 8 to 12 carbon atoms,

or where

R ⁸ and R ⁹ together for 4 to 15 carbon atoms, in particular 8 to 12

Cyclic groups containing C atoms,

R ¹⁵ Rl 5 Rl 5 _R i 5

R ⁶ for

- MI ¹ -, - CI ^or - CI - CI - stands-

where M ^{1 is} preferably silicon and

R ¹⁵ and R ¹⁶ are hydrogen, C ~ to _4, in particular methyl or C _ß - to Cι ₂ -aryl, especially phenyl.

Metallocene complexes of the general formula I which are symmetrical are preferred.

Rac.-Dimethylsilylenbis (2-methylindenyl) zirconium dichloride rac.-dimethylsilylenbis (2-ethylindenyl) zirconium dichloride rac.-ethylene bis (2-phenylindenyl) zirconium dichloride rac.-dimethylsilylenbis (2, 4, 6-trimethyldichloro) zirconium Dimethylsilylenbis (2, 4, 7-trimethylindenyl) zirconium dichloride rac.-Dimethylsilylenbis (2-methyl-4, 6-diethylindenyl) zirconium dichloride rac.-Dimethylsilylenbis (2-methyl-4,7-diethylindenyl) zirconium dichloride rac.- Dimethylsilylenebis (2-methyl-4,6-diisopropylindenyl) zirconium dichloride rac.-Dimethylsilylenbis (2-methyl-4,7-diisopropylindenyl) - zirconium dichloride rac.-Dimethylsilylenbis (2-ethyl-4, 6-diisopropylindenyl) - zirconium dichloride rac.-Dimethylsilylenbis (2-methylbenzindenyl) zirconium dichloride rac.-Dimethyl -ethylbenzindenyl) zirconium dichloride rac, -ethylenebis (2-methylbenzindenyl) zirconium dichloride rac, -ethylenebis (2-ethylbenzindenyl) zirconium dichloride rac.-ethylenebis (2-phenylbenzindenyl) zirconium dichloride

rac.-dimethylsilylenebis (2-methylindenyl) hafnium dichloride rac.-dimethylsilylenbis (2-ethylindenyl) hafnium dichloride rac.-ethylenebis (2-phenylindenyl) hafnium dichloride rac.-dimethylsilylenbis (2,4, 6-trimethylindenyl) hafnium-dichlorodichloride , 4, 7-trimethylindenyl) hafnium dichloride rac.-Dimethylsilylenbis (2-methyl-4,6-diethylindenyl) hafnium¬ dichlorid rac.-Dimethylsilylenbis (2-methyl-4,7-diethylindenyl) hafnium¬ dichloride rac.-Dimethylsilylenbis (2 -methyl-4,6-diisopropylindenyl) hafnium dichloride rac.-Dimethylsilylenbis (2-methyl-4,7-diisopropylindenyl) hafnium dichloride rac.-Dimethylsilylenbis (2-ethyl-4, 6-diisopropylindenyl) hafnium dichloride rac. -Dimethylsilylenebis (2-methylbenzindenyl) hafnium dichloride rac.-dimethylsilylenebis (2-ethylbenzindenyl) hafnium dichloride rac.-ethylenebis (2-methylbenzindenyl) hafnium dichloride rac.-ethylenebis (2-ethylbenzindenyl) hafniumdichidyldichlorid

Mixtures of several metallocene complexes can also be used.

Such complex compounds can be synthesized by methods known per se, the reaction of the appropriately substituted cyclic hydrocarbon anions with halides of titanium, zirconium, hafnium, vanadium, niobium or tantalum being preferred.

Examples of corresponding production processes are described, inter alia, in the Journal of Organometallic Chemistry, 369 (1989), 359-370. Suitable compounds B) forming metallocenium ions are in particular strong, neutral Lewis acids, ionic compounds with Lewis acid cations, ionic compounds with Bronsted acids as the cation and alumoxane compounds.

Compounds of the general formula V are strong, neutral Lewis acids

M ² X ² X ³ X ⁴ V

preferred in the

M ^{2 is} an element of III. Main group of the periodic table means, in particular B, Al or Ga, preferably B,

X ² , X ³ and X ⁴ for hydrogen, Ci- to Cio-alkyl, C ₆ - to -C ₅ 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 are, in particular for haloaryls, preferably for pentafluorophenyl.

Particularly preferred are compounds of the general formula V in which X ² , X ³ and X ^{4 are the} same, preferably tris (pentafluorophenyl) borane.

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

[(A ^{a +} ) QιQ ₂ ... Q _z ] ^{d +} VI

suitable in which

A an element of I. to VI. Main group or the I. to VIII. Subgroup of the periodic table means

Qi to Q _z for simply negatively charged residues such as Ci to

C ₂₈ alkyl, C ₆ to C ₅ aryl, alkylaryl, arylalkyl, haloalkyl, haloaryl each having 6 to 20 C atoms in the aryl and 1 to 28 C atoms in the alkyl radical,

Ci- to Cιo * -cycloalkyl, which can optionally be substituted with Ci- to Cio-alkyl groups, halogen, Ci to C ₂₈ alkoxy, C $ to Cis-aryloxy, silyl or mercaptyl groups

a stands for integers from 1 to 6, z stands 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 as well as cationic transition metal complexes are particularly suitable. The triphenylmethyl cation, the silver cation and the 1,1'-dimethylferrocenyl cation should be mentioned in particular. They preferably have non-coordinating counterions, in particular boron compounds, as they are also mentioned in WO 91/09882, preferably tetrakis (pentafluorophenyl) borate.

Ionic compounds with Bronsted acids as cations and preferably also non-coordinating counterions are mentioned in WO 91/09882; the preferred cation is N, N-dimethylanilinium.

Open-chain or cyclic alumoxane compounds of the general formula III or IV are particularly suitable as compound B) forming metallocenium ions

R ² k

Al-f-O Al-h -R21 III

R "

R ² 1

wherein R ^{21 represents} a Cx to C ₄ alkyl group, preferred

Methyl or ethyl group and m represents an integer from 5 to 30, preferably 10 to 25.

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

The oligomeric alumoxane compounds obtained are generally present as mixtures of both linear and cyclic chain molecules of different lengths, so that m is to be regarded as the mean. The alumoxane compounds can also be present in a mixture with other metal alkyls, preferably with aluminum alkyls. 97/10272 9 PO7EP96 / 03891

Furthermore, as component B) aryloxyalumoxanes, as described in US Pat. No. 5,391,793, aminoaluminoxanes, as described in US Pat. No. 5,371,260, aminoaluminoxane hydrochlorides, as described in EP-A 633 264, siloxyaluminoxanes, as in EP-A 621 279 described, or mixtures thereof are used.

It has proven to be advantageous to use the metallocene complexes and the oligomeric alumoxane compound in amounts such that the atomic ratio between aluminum from the oligomeric alumoxane compound and the transition metal from the metallocene complexes is in the range from 10: 1 to 10 ⁶ : 1, in particular is in the range from 10: 1 to 10 ⁴ : 1.

The catalyst system used in the process according to the invention can optionally also contain an aluminum compound of the general formula II as component C)

A1R ¹⁸ R ^{1 9} R ²⁰ II

in the

R ¹⁸ to R ^{20 represent} fluorine, chlorine, bromine, iodine or C 1 -C ₁ -alkyl, preferably C 1 -C 6 -alkyl

contain.

The radicals R ¹⁸ to R ²⁰ are preferably the same and stand for methyl, ethyl, isobutyl or n-hexyl.

Component C) is preferred in an amount of 500: 1 to

I: 1, in particular 350: 1 to 50: 1 (molar ratio AI from

II to transition metal from I) contained in the catalyst system.

Aromatic hydrocarbons are usually used as solvents for these catalyst systems, preferably with 6 to 20 carbon atoms, in particular xylenes and toluene and mixtures thereof.

The catalyst systems are preferably used in supported form.

The support materials used are preferably finely divided supports which preferably have a particle diameter in the range from 1 to 300 μm, in particular from 30 to 70 μm. Suitable carrier materials are, for example, silica gels, preferably those of the formula Si0 ₂ ^• a A1 ₂ 0 ₃ , where a is a number in the range is from 0 to 2, preferably 0 to 0.5; these are therefore aluminosilicates or silicon dioxide. Such products are commercially available, for example Silica Gel 332 from Grace. Other carriers include finely divided polyolefins, for example finely divided polypropylene or magnesium chloride.

The process according to the invention can be carried out in the gas phase, in suspension and in liquid monomers. Suitable suspending agents are, for example, aliphatic hydrocarbons. The process according to the invention is preferably carried out in the gas phase.

It has proven to be particularly preferred here if a supported catalyst system is used and polymerized at a pressure of 10 to 40 bar, preferably 15 to 32 bar over a period of more than 12 hours, preferably more than 24 hours.

The average molecular weight of the copolymers formed can be controlled using the methods customary in polymerization technology, for example by adding regulators such as hydrogen.

The copolymers produced by the process according to the invention fall with good, i.e. process morphology. The average particle diameter is preferably greater than 0.5 mm and preferably less than 5% by weight of the particles have a particle diameter of greater than 5 mm.

The solubility of the copolymers produced by the process according to the invention in xylene (at 20 ° C.) X _L obeys the relationship

XL <[94117 * exp (-0.0793 * T _m ) - 0.0245]% by weight,

where T _{m is} the melting point of the copolymer.

Is preferred

X _L <[542400 * exp (-0.1 * T _m ) + 0.5] wt%.

Those produced by the process according to the invention

Copolymers have a narrow molecular weight distribution M _w / M _n (M _w weight average, M _n number average). M _w / M _n is preferably less than 3. The process according to the invention can be carried out on an industrial scale, the amount of but-1-ene to be used is small and the copolymers produced by the process according to the invention can be used to produce films and moldings.

Examples

Example 1: Preparation of a supported metallocene catalyst

a) Production of the carrier material

1000 g of silica gel (SG 332, 50 μm, Grace; heated for 8 hours at 180 ° C. in a vacuum (1 mbar)) were suspended in 5 l of toluene under an atmosphere. At a temperature of 18 ° C., 7.75 l (6.83 kg) of 1.53 molar methylaluminoxane (MAO) solution (in toluene, from Witco) were added over 120 minutes. The mixture was then stirred for 7 h at room temperature, filtered and the filter cake washed twice with 2.5 1 of toluene. It was then dried in vacuo.

b) loading with the metallocene complex

1 kg of the silica gel containing MAO prepared under a) was placed in an evacuated vessel. A solution of 5.8 g (10 mmol) of rac.-dimethylsilylenebis (2-methylbenzindenyl) zirconium dichloride in 1.32 1 1.53 molar MAO solution (toluene) was then added with stirring. After pressure equalization with N ₂ , the mixture was mixed for 30 minutes at room temperature. The main amount of solvent was then distilled off in vacuo (initially at 20 ° C. until no more solvent passed over). The temperature was then increased in 5 ° C. steps to 55 ° C. and the catalyst was dried until it remained as an orange, free-flowing powder.

Examples 2 to 4:

Production of propene / but-1-ene copolymers in a continuous gas phase process

10 g / h of the supported metallocene catalyst prepared in Example 1 were metered into a 200 1 gas phase reactor. Propene and but-l-ene were fed in and copolymerized at 24 bar reactor pressure and 60 ° C. polymerization temperature, 30 mmol of triisobutylaluminum being fed in per hour (1 molar solution in heptane). The polymerization was carried out over a period of Operated continuously for 48 hours. The reactor output was 20 kg / h. A copolymer grit was formed.

The table below gives information about the amount of propene and but-1-ene used and the properties of the copolymers formed.

d _a vg means the average particle diameter of the polymer powder.

10 The Staudinger index [η] was determined at 135 ° C in decalin, the melting point T _m by means of DSC (differential scanning _. Calorimetry), the amount of C ₄ in the copolymer by IR and ¹³ C-NMR measurements, M _w (Weight average) and M _n (number average) by GPC (gel permeation chromatography).

15

The xylene-soluble fractions X _L were determined as follows:

500 ml of distilled xylene (mixture of isomers) were placed in a 1 liter three-necked flask equipped with a stirrer, reflux condenser and thermometer.

20 filled and heated to 100 ° C. The polymer was introduced at this temperature, then heated to the boiling point of the xylene and kept at reflux for 60 min. The heat supply was then cut off, cooled to 5 ° C. in the course of 20 min with a cooling bath and then heated again to 20 ° C. This tem-

The temperature was held for 30 min. The precipitated polymer was filtered off and exactly 100 ml of the filtrate were filled into a previously tared 250 ml single-necked flask. The solvent was removed from this on a rotary evaporator. The remaining residue was then added to the vacuum drying cabinet

30 80 ° C / 200 torr dried for 2 h. After cooling, the mixture was weighed out.

The xylene-soluble portion results from g x 500 x 100

35 XL G x V

X _L = xylene-soluble fraction in% g = quantity found G = product weight 40 V = volume of the amount of filtrate used

45

Claims

claims

Process for the preparation of propene / but-1-ene copolymers, the molar ratio of propene to but-1-ene being in the range from 10,000: 1 to 4: 1, characterized in that at temperatures in the range from 50 to Polymerized 120 ° C continuously and used as catalyst systems those which are active ingredients

A) Metallocene complexes of the general formula I

in which the substituents have the following meaning:

M titanium, zirconium, hafnium, vanadium, niobium or tantalum,

X fluorine, chlorine, bromine, iodine, hydrogen,

Ci to Cio alkyl, C ₆ to C ₁₅ aryl, alkyl aryl having 1 to 10 C atoms in the alkyl radical and 6 to 20 C atoms in the aryl radical, -OR ¹² or

-NR12R13,

in which

R ¹² and R ^{13 are} C 1 to C 10 alkyl, C ₆ to C ₅ aryl, alkyla ryl, arylalkyl, fluoroalkyl or fluoroaryl each having 1 to 10 C atoms in the alkyl radical and 6 to 20 C atoms in the aryl radical , R ¹ and R ^{7 are} Ci- to Cio-alkyl or Cζ- to Ci5 ~ aryl,

R ² and R ^{8 are} hydrogen, Cι ~ to Cio-alkyl, 5- to.

7-membered cycloalkyl, which in turn can carry a C ~ to Cio-alkyl as a substituent, or Si (R ¹⁴ ) ₃ with

R ¹⁴ Ci to Cio alkyl or C ₃ to Cio cycloalkyl

R ³ to R ⁵ and

R ⁹ to R ^{n are} hydrogen, C 1 to C ₀ alkyl, 5 to

7-membered cycloalkyl, which in turn can carry a C 1 -C to -alkyl as a substituent, Cζ- to cis-aryl or arylalkyl, where optionally two adjacent radicals together can represent cyclic groups having 4 to 15 C atoms, or Si (R ¹⁵ ) ₃ with

R ¹⁵ Ci to Cio alkyl, C ₆ to C ₅ aryl or

C ₃ - to Cio-cycloalkyl,

or where

R ² and R ³ together represent cyclic groups containing 4 to 15 carbon atoms,

or where

R ⁸ and R ⁹ together represent cyclic groups containing 4 to 15 carbon atoms,

R15 R "R15 _R 15

R ⁶ M ¹ • M ¹ - M ¹ Ml CR ₂ 1 ⁷ ,

Rl6 Rl6 Rl6 Rl6

_R 15 _R 15 R15 R15

0 ml _CC

R ¹⁶ R ⁱ⁶ Rl6 _R 16

= BR ¹⁵ , = AlRl ⁵ , -Ge-, -Sn-, -O-, -S-, = SO,

= S0 ₂ , = NR ¹⁵ , = CO, = PR ¹⁵ or = P (0) Ri ⁵ , wherein R ^{i 5} , R ¹⁶ and R ^{11 are the} same or different and a hydrogen atom, a halogen atom, a Cι-Cιo-alkyl group, a Cι-Cιo-fluoroalkyl group, a Cβ-Cio-fluoroaryl group, one

C ₆ ~ Cιo aryl group, a Cι -Cι ₀ alkoxy group, a C ₂ -Cιo ~ alkenyl group, a C ₇ -C ₄ o ~ arylalkyl group, a Cβ-Cήo-arylalkenyl group or a C ₇ -C ₄ o * or R ¹⁵ and R ^{i 6} or R ¹⁵ and R ^l ~ alkylaryl ⁷ each bil¬ with the atoms connecting them to a ring, and

M ^{α is} silicon, germanium or tin

contain,

B) a compound forming metallocenium ions and

C) optionally an aluminum compound of the general formula II

AlR ^l8 R ^l9 R ²⁰ II

in the

Rl ⁸ to R ^{20 are} fluorine, chlorine, bromine, iodine or -C ~ to -C ₂ alkyl.

2. The method of claim 1, wherein the molar ratio of propene to but-1-ene is in the range of 50: 1 to 5: 1.

3. Process according to claims 1 to 2, characterized gekennzeich¬ net that polymerized continuously at temperatures in the range of 60 to 100 ° C.

4. Process according to claims 1 to 3, characterized gekennzeich¬ net that M in general formula I represents zirconium or hafnium.

Process according to claims 1 to 4, characterized gekennzeich¬ net that as the metallocenium ion-forming compound B) open-chain or cyclic alumoxane compounds of the general formula III or IV ^R21 \

Al-f- 0 Al-i R ² ! II I

R ² 1

where R ^{21 is} a C 1 -C ₄ -alkyl group and m is an integer from 5 to 30,

be used.

6. Use of the copolymers obtained according to claims 1 to 5 for the production of films or moldings.

7. Films and moldings obtainable from the copolymers obtained according to claims 1 to 5 as essential components.