EP0851889A1

EP0851889A1 - Propene/but-1-ene copolymers

Info

Publication number: EP0851889A1
Application number: EP96931771A
Authority: EP
Inventors: David Fischer; Franz Langhauser; Dieter Lilge; Roland Hingmann; Günther SCHWEIER
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1995-09-11
Filing date: 1996-09-04
Publication date: 1998-07-08
Also published as: WO1997010286A1; JPH11512461A; CN1202186A; DE19533337A1

Abstract

Propene/but-1-ene copolymers contain at least 80 % by moles propene units, have a melting point Tm below 145 °C and a molecular weight distribution lower than 2.5.

Description

Propene / but-1-ene copolymers

description

The present invention relates to propene / but-1-ene copolymers with at least 80 mol% propene units, a melting point T _m less than 145 ° C. and a molecular weight distribution M _w / M _n less than 2.5.

The present invention further relates to the use of these copolymers 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 A.M. 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 with a higher rigidity. Low sealing temperatures are desirable for the applications mentioned, i.e. low melting points of the polymer. For this purpose, since the molar melting point reduction caused by the incorporation of butene is considerably less than that caused by the incorporation of ethene, very large amounts of butene (greater than 12 mol%) have been incorporated into the copolymer. Binary propene / but-1-ene copolymers with low melting points and a relatively low comonomer content are described in EP-A 318 049. These copolymers are prepared with homogeneous zirconocene catalysts in a solution polymerization at 0 ° C. The disadvantage here is that these copolymers are relatively low molecular weight and have relatively high xylene-soluble fractions, which indicates lower chemical uniformity and broadened molecular weight distributions.

It was therefore an object of the present invention to remedy the disadvantages mentioned and to provide propene / but-1-ene copolymers which, in particular, have a low melting point, a narrow molecular weight distribution and low xylene-soluble fractions.

Accordingly, the copolymers defined at the outset were found.

Furthermore, their use for the production of films or moldings and the films and moldings obtainable here were found. The propene / but-1-ene copolymers according to the invention have at least 80 mol% propene units in the copolymer, preferably 85 to 99.9 mol%, in particular 93 to 99.5 mol%, a melting point T _m less than 145 ° C, preferably less than 143 ° C and a molecular weight distribution M _w / M _n (M _w weight average, M _n number average) less than 2.5, preferably less than 2.3, particularly preferably less than 2, 15.

The polymers according to the invention preferably have a solubility in xylene X _L (20 ° C.) of

X _L <[94117 * exp (-0.0793 * T _m ) - 0.0245] wt%

on, especially from

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

Preferably 70% of the propene diads are in the form of meso diads.

Small amounts of other monomers can be used in the inventive

Copolymers may also be present, but preferably not more than 1 mol%, based on the amount of propene used.

Ethene and higher 1-olefins such as hex-1-ene, oct-1-ene and dec-1-ene are suitable here. However, binary propene /

But-1-ene copolymers.

The copolymers according to the invention can be prepared in the gas phase, in suspension, in liquid monomers or in inert solvents. Suitable suspension or solvents are, for example, aliphatic and aromatic hydrocarbons. The copolymers according to the invention are preferably produced in the gas phase.

In a preferred process for the preparation of the propene / but-1-ene copolymers according to the invention, the process is carried out by continuously polymerizing at temperatures in the range from 50 to 120 ° C. and using those used as catalyst systems 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, -C ~ to Cio-alkyl, Cζ- to cis-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 R ¹³ ,

in which

R ¹² and R ^{1 3} Ci to Cio-alkyl, C ₆ - to Ci s-aryl, alkylaryl, Aryl¬ alkyl, fluoroalkyl or fluoroaryl, each with 1 to 10 C atoms in the alkyl radical and 6 to 20 C atoms in the aryl radical mean,

R ¹ and R ⁷ Ci - to Cio-alkyl or C ₆ - to Cis-aryl,

R ² and R ^{8 are} hydrogen, Cι ~ to Cio-alkyl, 5- to 7-membered cycloalkyl, which is a Cι ~ to Cι o ~ alkyl

Can wear substituent, or Si (R ^{1 4} ) ₃ with

R ^{1 4} Ci - to Cio-alkyl or C ₃ - to Cι ₀ cycloalkyl

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

Cycloalkyl, which in turn can carry a Cχ ~ to Cιo ~ alkyl as a substituent, C ₆ - 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

R15 Ci to Cio-alkyl, Ce ~ to Cis-aryl or C ₃ - to CiQ-cycloalkyl,

or where R ² and R ³ together represent cyclic groups having 4 to 15 carbon atoms,

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

_R 15 _R 15 _R 15 R15 _R6

M ¹ . M ¹ M ¹ "M ¹ CR ₂ ^{1 /}

_R 16 _R 16 _R 16 _R 16

Rl5 _R 15 _R 15 _R 15

C 'OM ¹ ' CC -

Rl6 _R 16 _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 , where 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 Cε-Cio-fluoroaryl group, a C _ß -Cio aryl group, a Cι-Cιo ~ alkoxy group, a C ₂ -Cιo ^_ alkenyl group, a C ₇ -C ₄ o ~ arylalkyl group, a C ₈ -C ₄ o-arylalkenyl group or a C ₇ -Cjo 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

_A1R 18 _R 19 _R 20 _{τ τ}

in the

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

In a particularly preferred process, polymerization is carried out continuously at temperatures in the range from 60 to 100.degree.

Of the metallocene complexes of the general formula I used in the preferred process, those are preferred 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 is C _\ - to C ₄ -alkyl, in particular methyl or ethyl, or phenyl,

R ² and R ⁸ for -C ~ to C ₄ alkyl, in particular for methyl, ethyl, n-propyl, isopropyl, n-butyl or tert-butyl,

R ³ to R ⁵ and

R ⁹ to R ¹¹ are hydrogen, C ~ to _C4 alkyl, especially methyl, ethyl, n-propyl, isopropyl, n-butyl or tert-butyl, C _ß - to Cι ₂ -aryl, in particular phenyl, or where two neighboring radicals together represent 4 to 15 carbon atoms, in particular cyclic groups containing 8 to 12 carbon atoms,

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 represent 4 to 15 carbon atoms, in particular cyclic groups containing 8 to 12 carbon atoms,

R ^{1 5} Rl 5 Rl 5 _R 1 5 stands for - M ¹ , c or c C _'

⁶

where M ^{1 is} preferably silicon and

R ¹⁵ and R ^{16 are} hydrogen, Ci to C ₄ , in particular methyl or C ₆ to C ₂ aryl, in particular phenyl.

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

Are particularly 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-trimethylindenyl) zirconium dichloride raclor , 4, 7-trimethylindenyl) zirconium dichloride rac.-Dimethylsilylenbis (2-methyl-4, 6-diethylindenyl) zirconium dichloride rac.-Dimethylsilylenbis (2-methyl-4, 7-diethylindenyl) zirconium dichloride rac.-Dimethylsilylenbis (2 -methyl-4, 6-diisopropylindenyl) zirconium dichloride rac.-Dimethylsilylenbis (2-methyl-4,7-diisoρropylindenyl) zirconium dichloride rac.-Dimethylsilylenbis (2-ethyl-4, 6-diisopropylindenyl) zirconium dichloride rac. -Dimethylsilylenebis (2-methylbenzindenyl) zirconium dichloride rac

rac.-dimethylsilylenbis (2-methylindenyl) hafnium dichloride rac.-dimethylsilylenbis (2-ethylindenyl) hafnium dichloride rac.-ethylenebis (2-ρhenylindenyl) hafnium dichloride rac.-dimethylsilylenbis (2,4, 6-trimethylindenyl) hafnium bis-dichloride , 4, 7-trimethylindenyl) hafnium dichloride rac.-Dimethylsilylenbis (2-methyl-4, 6-diethylindenyl) hafnium dichloride 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.-Dimethylsilylenbis (2-methylbenzindenichloride) hafnium rac.-dimethylsilylenebis (2-ethylbenzindenyl) hafnium dichloride rac.-ethylenebis (2-methylbenzindenyl) hafnium dichloride rac.-ethylenebis (2-ethylbenzindenyl) hafnium dichloride rac.-ethylenebis (2-phenylbenzindenyl) hafnium dichloride

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 manufacturing processes include 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 χ 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, Ce to Cis-aryl, alkylaryl, arylalkyl, haloalkyl or haloaryl, each with 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the Aryl radical or fluorine, chlorine, bromine or iodine, 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 with 6 to 20 C atoms in the aryl and 1 to 28 C atoms in the alkyl radical,

Ci- to Cio-cycloalkyl, which can optionally be substituted with Ci- to Cio-alkyl groups, halogen, Cχ ~ to C ₂₈ alkoxy, Ce 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 a-z, however, 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 ^2l .

Al-f-0 Al-i R ²¹ III

R ² *

R ²¹

wherein R ^{21 is} a -C ~ 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.

As a rule, the oligomeric alumoxane compounds obtained are mixtures of different lengths, both linear and cyclic chain molecules, 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.

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 US Pat

EP-A 621 279, or mixtures thereof, are used.

It has proven 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 in the range from 10: 1 to 10 ⁴ : 1.

The catalyst system 5 used in the preferred process may optionally also contain an aluminum compound of the general formula II as component C)

A1R ¹⁸ R ¹⁹ R ²⁰ II

0 in

R ¹⁸ to R ^{20 represent} fluorine, chlorine, bromine, iodine or Ci - to -C ₂ alkyl, preferably Ci - to Cβ-alkyl

5 included.

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

Component C) is preferably present in the catalyst system in an amount of 500: 1 to 1: 1, in particular 350: 1 to 50: 1 (molar ratio Al from II to transition metal from I).

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 5 carrier materials are, for example, silica gels, preferably those of the formula Si0 ₂ * a Al ₂ O ₃ , in which a stands for a number in the range from 0 to 2, preferably 0 to 0.5; these are therefore aluminosilicates or silicon dioxide. Products of this type are commercially available, for example Silica Gel 332 from Grace. More carriers

40 include finely divided polyolefins, for example finely divided polypropylene.

It has proven to be particularly preferred if a supported catalyst system is used and at a pressure of 45 10 to 40 bar, preferably 15 to 32 bar over a period of polymerized for 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 molar ratio of the propene and butene monomers used is preferably 10,000: 1 to 4: 1, in particular 200: 1 to 5.5: 1.

The propene / but-1-ene copolymers according to the invention have a low melting point, a narrow molecular weight distribution and low xylene-soluble fractions. They are suitable for the production of films and moldings, in particular sealing layers and injection molded articles.

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 g of the metallocene support catalyst produced 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 continuously over a period of 48 hours. The reactor output was 20 kg / h. A copolymer grit was formed.

The following table provides information about the amount of propene and but-l-ene used and the properties of the copolymers formed.

d _avg means the average particle diameter of the polymer _powder .

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 emulsion chromatography).

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

500 ml of distilled xylene (mixture of isomers) were introduced into a 1 liter three-necked flask equipped with a stirrer, reflux condenser and thermometer and heated to 100.degree. 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 temperature was kept 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

80 ° C / 200 torr dried for 2 h. After cooling, the mixture was weighed out. The xylene-soluble portion results from gx 500 x 100 ^{XL =} G x V XL = xylene-soluble portion in% g = found amount G = product weight V = volume of the amount of filtrate used

Claims

claims

1. propene / but-1-ene copolymers with at least 80 mol% propene units, a melting point 1 _m below 145 ° C. and one

Molecular weight distribution M _w / M _n less than 2.5.

2. propene / but-1-ene copolymers according to claim 1 with a solubility in xylene X _L (20 ° C) of

X _L <[94117 * exp (-0.0793 * T _m ) - 0.0245] wt%.

3. propene / but-1-ene copolymers according to claims 1 to 2, with a solubility in xylene X _L (20 ° C) of

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

4. Use of the propene / but-1-ene copolymers according to claims 1 to 3 for the production of films or moldings.

5. Films and moldings obtainable from the copolymers according to claims 1 to 3 as an essential component.