CA2010065C

CA2010065C - Process for the preparation of a random propylene copolymer

Info

Publication number: CA2010065C
Application number: CA002010065A
Authority: CA
Inventors: Volker Dolle; Martin Antberg; Jurgen Rohrmann; Andreas Winter
Original assignee: Hoechst AG
Current assignee: Basell Polyolefine GmbH
Priority date: 1989-02-15
Filing date: 1990-02-14
Publication date: 2000-06-13
Anticipated expiration: 2010-02-14
Also published as: AU4939890A; AU622980B2; JP3148217B2; CA2010065A1; ZA901115B; DE59000438D1; JPH02247207A; EP0384263B1; EP0384263A1; DE3904469A1; ES2052986T3

Abstract

Process for the preparation of a random propylene copolymer Copolymerization of propylene with small amounts of other olefins in the presence of a catalyst composed of a metallocene of the formula I

Description

~_~.~~D~;~
HOECHST ~iR~TENGESELLSCHAI~'T HOE 89/F 053 Dr.DA/bs Description Process for the preparation of a random propylene copolymer The polymerization of olefins, depending on the process used, gives copolymers with different properties and different proportions of comonomerss a) random copolymers with a low proportion of comonomers, b) polymer blends containing a larger proportion of incorporated comonomers than the random copolymers and c) copolymer rubbers containing the comonomers incor-porated in similar proportions.
As a rule, random copolymers differ from the correspond-ing homopolymers in having a lower crystallinity and a lower hardness. It is desirable for the random copolymers to have as random a chain structure as possible. The prior art olefin copolymers which are prepared with the aid of heterogeneous catalysts can only fulfil this requ:irernent to a very limited extent.
Random terpolymers of CZ/C;~/Cn with n > 3 have been described and were obtained using heterogeneous catalysts (cf. EP 263,718). The proportion of C3 is 97 to 86 mol the proportion of CZ is 0.5 to 6 ~ and the proportion of Cn (n > 3) is 2 to 13 mol ~C. The material has good heat sealing properties but is obtained in a two step process with a suspension polymerization step and a gas phase polymerization step. In order to obtain the desired anti-blocking properties, a terpolymer with a high proportion of the third monomer has to be prepared. However bipoly-mere are however required since these are easier to manipulate and have a chemically homogeneous chain structure.
furthermore, random C2/C~ copolymers are known, prepared by suspension polymerization ( cf . EP 74,194 ) . In order to ~:~~.~3~E~~
obtain the desired properties, the polymers obtained must be broken down. Moreover, the proportion of ethylene is greater than 6 $. This high proportion of C2 is necessary in order to reduce the chemical inhomogeneity of a heterogeneous catalyst system, this inhomogeneity tending to produce a relatively high proportion of crystallizable sequences in the polymer.
Finally, an ethylene/propylene copolymer with a high proportion of ethylene and a process for its preparation has been described (cf. JP 62/121,707). The process is carried out using ethylenebisindenylzirconium dichloride at a temperature of less than -10°C and is consequently unsuitable for industrial production. Apart from that, the activity of the catalyst is very low. ., The object was therefore to provide a process for the preparation of a propylene copolymer, which can be carried out within an industrially relevant temperature range with adequate catalyst activity and provides a copolymer which is suitable for thermoforming and blow molding.
It was found that this object can be achieved by copoly-merization of propylene with other olefins in the pre-sence of certain metallocene catalysts.
The invention accordingly provides a process for the preparation of a propylene copolymer composed of 99.9 to 80.0 mol ~, relative to the total polymer, of propylene units and 0.1 to 20.0 mol ~, relative to the total polymer, of units which are derived from ethylene or from an olef in with at least 4 carbon atoms of the formula R15-CH=CH-Rle, where Ri5 and R18 are identical or different and denote a hydrogen atom or an alkyl radical having 1 to 28 carbon atoms or R15 and RiB with the carbon atoms bonding them form a ring having 4 to 28 carbon atoms, by polymerizing 50 to 99.5 ~ by weight, relative to the total amount of monomers, of propylene and 0.5 to 50 ~ by - ~ - ~~.~~E~;~
weight, relative to the total amouwt of monomers, of at least one representative of the group consisting of ethylene and olefins having at least 4 carbon atoms of the formula Rls-CH=CH-Rls, where Rlj and Rls have the meaning given above, at a temperature of 30 °C to x.50 °C at a pressure of 0.5 to 100 bar in solution, in suspension or in the gas phase in the presence of a catalyst com-posed of a metallocene and an aluminoxane, wherein the metallocene is a compound of the formula I
R'1 ( CRBR~ D m Z0 R'~ R 7 I
R R R
iCRBR9?n in which R1 and RZ are identical or different and denote a hydrogen atom, a C1-C1o-alkyl group, a Cl-Clo-alkoxy group, a Cs-Clo-aryl group, a Cs-Clo-aryloxy group, a CZ-Clo-alkenyl group, a C~-Cao-arylalkyl group, a C~-C4o-alkylaryl group, a Cs-Cqo-arylalkenyl group or a halogen atom, R3, R', RS and Rs are identical or different and denote a hydrogen atom, a halogen atom, a Cl-Clo-alkyl group, a radical -NRz -, -SR1°-, -OSiR3°-, -SiR3°- or -PRZ°-in which Rz° is a Cl-Cl°-alkyl group, a Cs-Cz°-aryl group or if the radical contains Si or P may also be a halogen atom, or each pair of adjacewt radicals R3, R', R5 or Rs forms a ring with the carbon atoms linking them, R' is Rll Rll Rll Rll Rll M M , _ Ml _ , _ 1 _ 1 _ M1 _ CR2 _ . _ O _ Ml _ O _ g12 X12 X12 R12 X12 1 t C - . - O - ~1 -~~.~D~~~
=BRZ1, =~a1R11, -Ce-, -sn-, -o-, -s-, =so, =gp2, =p~11, =pRll or =g(o)RW
where R1', R1z and Rz3 are identical or different and denote a hydrogen atom, a halogen atom, a Cl-C3o-alkyl group, a C1-C1o-flaaoroalkyl group, a Ce-C~o-ax~yl group, a Cs-Clo-fluoroaryl group, a Cl-Clo-alko3ry group, a C2-Clo-alkenyl group, a C,-C~o°arylal~~cyl group, a Cg C4o-arylalkenyl group, a C~-C4o-81ky1~iry1 group or R1g and R12 or Rzl and R13 in each case form a ring with the atoms bonding them, X11 is silicon, germanium or tin, Ro and R9 are identical or different and have the meaning given for Rzl, m and n are identical or different and are zero, 1 or 2, m glue n being zero, 1 or 2, and the alum.ino~cane is one of the formula (II) R~4 -Rig Rx4 A1 - O AI ~ A1 r (II) R14 ''~ p ' . R14 in the instance of the linear type andfor of the formula (III) (III) p~2 in the instance of the cyclic type, R1" in the formulae ( I I ) and ( I I I ) denoting a C1-CB-alkyl group and p denoting an integer from 2 to 50.
The invention furthermore relates to the copolymer prepared by the above process and to its use for the preparation of thermoforming sheets and for the blow-- 5 ~ ~:~~.C~~D~~
molding of hollow articles.
The catalyst which is to be used for the process accord-ing to the invention is composed of an aluminoxane and a metallocene of the formula T.
R~ ccR~Rg~m BHP
R~ R5 R
tCRBRg)n _U
R~ R~
R1 and RZ are identical or different and denote a hydrogen atom, a C1-Clo°, preferably Cl-C3-alkyl group, a Cl-Clo- r preferably Cl-C3-alkoxy group, a Cs-Cso-, Preferably Cs-Cs-aryl ,clroup, 1~ a Cs-Clo-, preferably Cs-Cs-aryloxy group.
a C~-Clo-, preferably Ca-C,~-.alkenyl group, a C'-C~°-, preferably C~-Cl°-arylalkyl group, a C,-C4o-, preferably C~-C12-alkylaryl group, a CB-Cao-, preferably C8-Cxz-arylalke~zyl group, or a halogen atom, preferably chlorine.
R3, R°, R5 and Rs are identical or different and denote a hydrogen atom, a halogen atom, preferably a fluorine, chlorine or bromine atom, a Cz-C1°-, preferably C1-C3-alkyl group, a radical -I~1R2 -, -SRS°-, -OSiR3°-, -SiR3°- or -PRz -, where Rl° is a C~-C2°, preferably Cl-C~-alkyl group or Cs-Coo-. preferably Cs-Ce-aryl group, or in the case of radicals containing Si or P may also be a halogen atom, preferably a chlorine atom, or each adjacent pair of radicals R3, R", RS or Rs forms a ring with the carbon atoms bonding them. Particular preference is given to indenyl, fluorenyl and cyclopentadienyl ligands.
R~

_ ~"~~.~~~
R' is Rll Rll Rll Rll Rll is s - M1 - - Ml - M1 - , - Ml - CR2 - , - O - M1 - O -R12 , X12 X12 g12 gZl2 R11 Rll - C - s ° O - M1 g12 p~12 =SRll, =A1R11, -GQ-, -Sn-, -O-, -S-, DSO, ~SOa, ~IJR11, NCO, =FR11 ox ~F ( O) Rlg, ia'here R11, R~ and R13 ~lre identiC:al or different and denote a hydrogen atom, a halogen atom, a C~-C3o, preferably C1-C4-alkyl group, in particular a methyl group, a Cl-Clo-fluoroalkyl graup, preferably a CF3 group, a Ce-Clo-fluoroaryl group, preferably a penta fluorophenyl group, a Cg-Clo-, preferably C6-Ce-aryl group, a C1-Clo°. preferably C1-C4-alkoxy group, ~.r~ particular a methoxy group, a Cz-Clo-, preferably Cz-C4-alkenyl group, a C~-C4o-, preferably C~-Clo-arylalkyl group, a Ce-Cao-.
preferably C8-Clz-arylalkenyl group or a C~-C4o-, preferably C~-Clz-alkylaryl group, or R~1 and Rlz or Ri' and Rl3 in each case together form a ring with the atoms bonding them.
14T1 is silicon, germanium or tin, preferably silicon and germanium.
R' is preferably =CRllRizr =SiRllRlz, =GeR11R12A -~_~ -S_~
-SO, -PR'1 or =P ~ O ) Rl' .
R8 and Re are identical or different and have the meaning given for Rli.
m and n are identical or different and denote zero, 1 or 2, preferably zero or 1, where m plus n is aero, 1 or Z, preferably zero or 1.
The metallocenes described above can be prepared by the 2~ following general reaction scheme:

~ - ~~~.~t~f~J
F32R~ + ButylLi --~~ FiR~L~.
~-(CR8R9)m-R7°(CR8R9)n-X
H2Rb * ButylLi -----.~ HRbLi HRay ( cRaR~ ) ~,- R~- ( cRgR~ ) n- RAH ~i~
LiRa- (CRBR~)tn'R~- (CR8R9)n-RbLi gIfCl4 (CR8R9)m_Rs (~BR~)m_Ra t t o C1 ~ ~ Rl R~ Hf ~ RR~ Hf'~ R~L~
t C1 ~ I C1 i t (cR8R~)n_R~ (cR8R9)~_~~
(CR8R9)~_Ra R
R7 Iif a a R2 i (CRBR~)n_Rb (~ = C1, Br, I, O-tosyl, HR° ~ R3 ~ g , HRb = R~ ~ H ) Preferred metallocenes are those of the formula I in which the radical - ( CR8R8 ) m R'- ( CReR9 ) p denotes -CHx-CHx-, -Ge(CH3)x-r -Si(CH3)x-, -Si(Cells~x- or -Si(CH3) (CBHS)-.
Particular preference is given to the use of the follow-ing metallocene compoundsa ethylenebisindenylhafnium dichloride (= 1) and bisindenyldimethylsilylhafnium dichloride (_ - ~~~.C~~~~
The cocatalyst is an aluminoxane of the formula II
gl.~ ~ R14 ~ g14 X11 - O - Al - O - 1~1 ( zT ) R1~ ~ ~ R1~
P
in the instance of the linear type and/or of the formula (IZa) g14 ~~ - o - (xaI) P~2 in the instance of the cyclic type. In these formulae, gla denotes a Cl-C6-alkyl group, greferably methyl, ethyl or isobutyl, in particular methyl, and p denotes an integer from 2 to 50, preferably 5 to 40. However, the exact structure of the aluminoxane is not known.
The aluminoxane can be prepared by various methods.
One possibility is the careful addition of water to a dilute solution of a trialkylaluminum by adding the solution of the trialkylaluminum, preferably trimethyl-aluminum, and the water each in small portions to a previously introduced relatively large amount of an inert solvent and at each stage waiting until gas evolution has ended.
In another process, a slurry of finely powdered copper sulfate pentahydrate is prepared in toluene and admixed in a glass flask, under inert gas at about -20°C, with an amount of trialkylaluminum such that for every 4 gram _ g atoms of A1 there is available about 1 mole of CuS~a.5H20.
After slow hydrolysis with alkane elimination the reac-tion mixture is left for 24 to 48 hours at room temper-ature, which may require cooling so that the temperature does not exceed 30°C. the aluminoxane dissolved in toluene is then separated from the copper sulfate by filtration and the solution is concentrated in vacuo. It is assumed that during this preparation the low molecular weight aluminoxanes condense with elimination of tri-alkylaluminum to form higher oligomers.
Furthermore, aluminoxanes are obtained if trialkyl-aluminum, preferably trimethylaluminum, dissolved in an inert aliphatic or aromatic solvent, preferably heptane or toluene, is brought into reaction at a temperature of -20 to 100°C with aluminum salts containing water of crystallization, preferably aluminum sulfate. In this process, the ratio by volume between the solvent and the alkylaluminum used is isl to 50x1, preferably 5:1, and the reaction tame, which can be monitored from the.
elimination of the elkane, is 1 to 200 hours, preferably 10 to 40 hours.
Particular preference is given to aluminum salts contain-ing a high proportion of water of crystallization.
Hydrated aluminum sulfate is especially preferred, particularly the compounds A12 ( SOa ) 3 ~ 16H20 and Alz ( S04 ) 3 ~ 18H2~3 with the particularly high proportion of water of crystallization of 16 and 18 moles of HZO/mole of AL2(.~.~p)3' Another alternative for the preparation of aluminoxanes is to dissolve trialkylaluminum, preferably trimethyl-aluminum, in a suspension medium which has been previously introduced into the polymerization vessel, preferably in liquid monomer in heptane or toluene and then to react the aluminum compound with water.
In addition to the processes which have been described above for the preparation of aluminoxanes, there are other usable processes.
Whatever the method of preparation, all solutions of aluminoxane contain a variable amount of unconverted trialkylaluminum which is present in the free state or as an adduct.
The metallocene can be preactivated be:~ore use in the polymerization reaction with an alum.inoxane of the formula (TI) and/or (TIT). This significantly increases ZO the polymerization activity and improves the particle morphology.
'The preactivat3on of the transition metal compound is carried out in solution. Here, it is preferable to dissolve the metallocene in a solution of the aluminoxane in an inert hydrocarbon. Suitable hydrocarbons afire aliphatic or aromatic hydrocarbons. Toluene is preferably used.
The concentration of the aluminoxane in the solution is in the range of from about 1 ~ by weight up to the saturation limit, preferably of 5 to 30 ~ by weight, relative in each case to the total solution. The metal-locene can be used in the same concentration, but is preferably used in an amount of 10-4 - 1 mole per mole of aluminoxane. The preactivation time is 5 minutes to 60 hours, preferably 5 to 60 minutes. Preactivation is carried out at a temperature of -78°C to 100°C, prefer-ably 0 to 70°C.
The polymerization is carried out in a known manner in solution, suspension or in the gas phase, continuously or batchwise, in one or more steps at a temperature of 30 to 150°C, preferably 30 to 80°C. Propylene is copolymerixed with at least one representative of the group consisting of ethylene and olefins having at least 4 carbon atoms of the formula R15-~H=CH-Rls. In this formula, ~t15 and Ris are identical or different and denote a hydrogen atom or an - 1 ~ - ~'~.C~t~~6~
alkyl radical having 1 to 28 carbon atoms. However, Rls and R'6 may also form a ring with the carbon atoms bonding them which contains 4 to 28 carbon atoms. Examples of olefins of this type are 1-butane, 1-hexane, 4-methyl-1-pentane, 1-octane, norbornene, norbornadiene, cyclopen-tene, cyclohexene and cyclaoctene. The amount of propylene used is 50 to 99.5, preferably ~0 to 99 ~c by weight, relative to the total amount of monomers, and the amount of comonomer, there being at least one, is 0.5 to 50, preferably 1 to 40 ~ by weight relative to the total amount of monomers.
If necessary, hydrogen is added as a molecular weight regulator. The total pressure in the polymerization system is 0.5 to 200 bar. Preference is given to polymer-ization in the industrially particularly relevant pres-sure range of 5 to 64 bar.
In polymerization, the metallodene compound is used in a concentration, relative to the transition metal, of 10-' to 10-', preferably 10-4 to 10-6 moles, of transition metal per dm3 of solvent or per dm~ of reactor volume. The aluminoxane is used in a concentration of 10-s to 10-1 moles, preferably 10-4 to 10-2 males per dm3 of solvent ar per dm3 of reactor volume. However, in principle higher concentrations can also be used.
If the polymerization is a suspension or solution poly-merization, an inert solvent customary for the Ziegler process is used. The polymerization may be carried out for example in an aliphatic or cycloaliphatic hydro-carbon; examples of these are butane, pentane, hexane, heptane, isooctane, cyclohexane, and methylcyelahexane.
naphtha fraction or hydrogenated diesel oil fraction may also be used. It is also possible to use toluene.
Preference is given to polymerization in liquid monomer.
If inert solvents are used, the monomers are metered. in in the gaseous or liquid form. If only one monomer is _ 12 - ~~~.~~~5 used as the suspending medium, the comonomer(s) is/are metered in in the gaseous or liquid form. Furthermore, it is possible to carry out the polymerization in a mixture of different monamers as the suspending medium; a further monomer can then be metered in liquid or gaseous form. It is advantageous when using ethylene to charge part of the ethylene initially and then to meter in the remainder during the polymerization.
The duration of the polymerization is optional, since the catalyst system which is to be used according to the invention has only a slight loss of polymerization activity over time.
.A feature of the process according to the invention is that the hafnium compounds used are very heat stable so that they can also be used with high activity at tempera-tures up to 90°C. Moreover, the aluminoxanes used as cocatalysts can be added in lower concentrations than hitherto. Finally, it has now become possible to prepare random copolymers at industrially relevant temperatures.
The copolymer (or terpolymer) prepared according to the invention is a copolymer (terpolymer) composed of 99.9 to 80.0 mol ~, relative to the total polymer, of propylene units and 0.1 to 20.0 mol ~, relative to the total polymer, of units which are derived from the above Z5 comonomers in which the comonomers are incorporated in blocks with an average sequence length n < 1.25. The copolymers have a uniform composition i.e. no distribu-tion of composition is observed> The polydispersity ~,/Mn is in the range of 2.5 to 5.5 and the molecular weight is in the range of about 100,000 to 360,000 g/mole. Due to these molecular properties, the copolymers have, in addition to low crystallinity, a high transparency, are not tacky and have an enormous tensile strength.
The sequence length of the comonomer blocks in the copolymers according to the invention are preferably '~~~.~t'~~ a below 1.25, particularly below 1.2 and especially below 1.1.
The invention is described in more detail in the follow-ing examples.
The following symbols are useds V'~ = viscosity number in cma/g I~" = weight average mole- determined by gel perinea cular weight Lion chromatography (data M" = number average mole- in units of g/mole) cular weight Mw/Mn = polydispersity average block length n~2 = polyethylene (the block lengths were determined by 13C-INPiR spectro_ soapy) example 1 A dry 16 dm~ vessel was purged with nitrogen and charged with 10 dm3 of liquid propylene. Then 35 cm~ of methyl-aluminoxane solution in toluene (_ :~iAO, corresponding to 50.7 mmols of A1, having an average degree of oligomer-ization n = 30) were added and the batch was stirred at 30~C for 15 minutes. 12 g of ethylene were then added.
meanwhile, 52.5 mg (= 0.103 mmols) of bisindenylethylene-hafnium dichloride were dissolved in 16 cm3 of ~IAO (_ 23.2 mmols of A1) and preactivated by being left to stand for 15 minutes.
The solution was then added to the vessel. The polymeriz-ation system was brought to a temperature of 60°C and the polymerization begun. During the following 120 minutes, 38 g of ethylene were added in small portions and the temperature maintained. -- 14 - ~~.'~1~~5 1.33 kg of random ethylene-propylene copolymer were obtained. The activity was thus 12.7 kg of PP/g of metallocene/h or 6.5 PP/mmols of Hf/h.
The following analytical data were determined from the polymers V2 - 168 cm~/g, M" = 196000 g/mole, M" = 44550 g/mole, M,oJl~i~, = 4.4, n~a -- 1.0, 3.5 ~ by weight of incorporated ethylene, Tm = 126.5°C, eHm = 65 ~lg.
Example 2 The procedure of Example 1 was followed. 23 g of ethylene were charged. During the polymerization, 68 g of ethylene were metered in.
The polymerization time was likewise 2 hours. 40.0 mg (0.078 mmols) of metalloeene compound were used. 1.42 kg of random ethylene-propylene copolymer were obtained. The.
activity of the metallocene was thus 17.8 kg of PP/g of metallocene/h or 9.0 kg of PP/mmol of Hf/h.
V~ - 182 cm3/g, 1~, = 207000 g/mole, Ma = 46000 g/mole, = 4.5, n~2 = 1.0, 6.4 ~ by weight of incorporated ethylene, Tm = 127 °C, dI~ = 67 3/g.
Example 3 The procedure of Example 1 was followed. 1.5 g of ethyl-ene were charged. During the polymerization, 4.5 g of ethylene were metered in.
The polymerization time was likewise 2 hours. 49.0 mg (0.096 mmols) of metallocene compound were used. Z.43 kg of random ethylene-propylene copolymer were obtained. The activity of the metallocene was thus 22.8 kg of PP/g of metallocene/h or 11.6 %g of PP/mmol of Hf/h.

~~~~.~1~~~
-- 15 _ V2 -- 137 cm3/g, M" = 151000 glmole, 3~ = 30200 glmole, ~"!M" = 5.0, aa~2 = 1.0, 2.4 ~ of incorporated ethylene, Tm = 126 °C, eHm = 69 J/g.
$xample 4 The procedure of Example 1 was followed, but 13.5 g of ethylene were charged. During the polymerization, 40 g of ethylene were metered in.
The polymerization time was likewise 2 hours. 53.4 mg (0.105 mmolj of metallocene compound were used. 2.53 kg of random ethylene-propylene copolymer were obtained. The activity of the metallocene was therefore 23.7 kg of PP/g of metallocene/h or 12.0 kg of PP/mmol of Hf/h.
VZ = 154 cm3/g, 1~,, = 168000 glmole, Tai" = 303500 g/mole, ~,/M=, = 5.8, n~z = 1.0, 2.1 ~ by weight of incorporated ethylene, Tm = 126.8°C, eH,~ = 70 J/g.
8xample 5 The procedure of Example 1 was followed, but 30.5 g of ethylene were charged. During the polymerization, 92 g of ethylene were metered in.
The polymerization time was likewise 2 hours. 56.5 mg (0.111 mmolj of metallocene compound were used. 1.45 kg of random ethylene-propylene copolymer were obtained. The activity of the metallocene was thus 15.5 kg of PP/g of metallocene/h or 7.9 kg of PP/mmol of Hf/h.
VZ - 190 cm3/g, 1~ = 217000 g/mole, I~ = 41750 g/mole, 1~,/Ma = 5.2, n~2 = 1.0, 8.4 ~ of incorporated ethylene, Tm = 127°C, eHm = 6i J/g.
Hxample 6 The procedure of Example 1 was followed. 13 g of ethylene were charged and then 120 g of 1-butane. During the polymerization, 40 g of ethylene were metered in.
The polymerization tame was likewise 2 houxs. 64.5 mg (0.127 mmol) of metallocene compound were used.
2.05 kg of random ethylene-propylene-butane terpolymer were obtained. The activity of the meta:llocene was thus 15.9 kg of PP/g of metallocene/h or ~.1 kg of PP/mmol of Hf/h.
VZ = 160 cm3/g, 1~ = 1790~~ g/mole, Pi=, = 400~0 g/mole, Mw,/Mn = 4.5, nCZ = 1.0, 2.6 ~ of incorporated ethylene, T~ = 126 .5 °C, eH~ = 65 J/g.
Example 7 The procedure of Example ~. was followed: 35 g of ethylene were charged and then 70 g of 1-butane. During i:he polymerization, 105 g of ethylene were metered in.
The polymerization time was likewise 2 hours. 64.5 mg (0.127 mmol) of metallocene compound were used. 2.70 kg of random ethylene-propylene-butane terpolymer were obtained. The activity of the metallocene was thus 21.0 kg of PP/g of metallocene/h or 10.6 kg of PP/ma~ol of Hf/h.
'~Z - 130 cm3/g, Mo, = 142000 g/mole, Mn = 26320 g/mol, M~/1~ = 5.4, n~2 = 1.0, 5.2 ~ of incorporated ethylene, Tm = 126 °C, n~ = 67 J/g.
Example 8 The procedure of Example 1 was followed, but 50°C was selected as the polymerization temperature. 30 g of ethylene were charged. During the polymerization, 95 g of ethylene were metered in.

_ 17 -The polymerisation time was likewise 2 hours. 55.7 mg {0.110 mmol) of metallocene compound were used. 2.15 kg of random ethylene/propylene copolymer were obtained. The activity of the metallocene was thus 19.3 kg of PP/g of metallocene/h or 9.8 kg of PP/mmol of Hf/h.
vz = 1.34 cm3/g, P~,, = 115000 g/mole, M" = 20900 g/mole, Ma,/~, = 5.5, n~2 = 1.0, 5.7 ~ of incorporated ethylene, Tm = 127°C, dH,a = 69 J/g.
Bxample 9 The procedure of Example 1 was followed, but 70°C was selected as the polymerization temperature. 11 g .of ethylene were charged. During the polymerization, 35 g of ethylene were metered in.
The polymerization tune was likewise 2 hours. 45.5 mg {0.089 mmol) of metallocene compound were used. 1.74 kg of random ethylene/propylene copolymer were obtained. The activity of the metallocene was thus 19.1 kg of PP/g of metallocene/h or 9.7 kg of PP/mrnol of Hf/h.
vZ - 158 cm3/g, M~ = 158000 glmole, Mn = 32400 g/mole, t~"/F~, = 4 .9, nCZ = 1. 0, 2 . ~ ~ by weight of incorporated ethylene, Tm = 128°C, nF~ = 68.5 J/g.
Bzample 10 The procedure of Example 1 was followed, but the catalyst used was bisindenyldimethylsilylhafnium dichloride. 10 g of ethylene were charged. During the polymerization, 35 g of ethylene were metered in. Polymerization Bias carried out for two hours at 60°C. 53 mg (0.099 mmol) of metallocene compound were used. 0.88 kg of random ethylene-propylene copolymer were obtained. The activity of the metallocene was thus 8.3 kg of PP/g of metallocene/h or.4.4 kg of PP/mmol of Hf/h.

~~~~.~~D~~~
-ls-Vz - 2s5 cm3/g, ~ = 336000 g/mole, r~, = 65900 g/m~le, I~~,/.MI, = 5.1, n~z = 1.0, 4.9 $ of incorporated ethylene, Tm = 127.5°C, eHm = 62 J/g.
Example 11 The procedure of Example ZO was followed. 1 g of ethylene was charged. During the polymerization, 5 g of ethylene were metered in. Polymerization was carried out for two hours at 60°C. 47.2 mg (0.088 ~aol~ of metallocene compound were used. 2.4 kg of random ethylene-propylene copolymer were obtained. The activity of the metallocene was thus 25.4 kg of PP/g of metallocene/h or 13.6 kg of PPJmmol of Hf/h.
VZ - 272 cm3lg, I~, = 310000 g/mole, 'N.h = 68000 g/mole, P~"/1~, = 4.7, n~z = 1.0, 0.2 ~ of incorporated ethylene, Tm = 12x.5°c, eHm = 65 J/g.
Example z2 The procedure of Example 10 was followed. 7.5 g of ethylene were charged. During the polymerization, 25 g of ethylene were metered in. Polymerization was carried out for two hours at 60°C. 53.3 mg (0.103 mmol) of metal-locene compound were used. 2.3 kg of random ethylene-propylene copolymer were obtained. The activity of tine metallocene was thus 20.8 kg of PP/g of metallocene/h or 11.2 kg of PP/mmol of Hf/h.
VZ = 295 cm3/g, M~, = 349000 g/mole, 3~, = 79000 g/mol~e, 1~/M" _ 4.4, n~z = Z.O, 1.3 ~ s~f incorporated ethylene, Tm = 128°C, eI~ = 67 J/g.
Example Z3 The procedure of Example ZO was followed. I1 g of ethyl-ene were charged. During the polymerization, 36 g.of ethylene were metered in. Polymerization was carried out a~~~..~~~~~

for two hours at 60°C. 57.8 mg (0.108 mmol) of metal locane compound were used. 1.7 Jzg of random ethylene propylene copolymer were obtained. The activity of the metallocene was thus 14.7 3cg of PP/g of metallocene/h ox 7.8 Dcg of PP/mmol of I3f/h.
VZ -- 277 cm3/g, .M", = 320000 g/mole, I~, = 77600 glmole, Mo,/Ma = 4.2, n~2 = 1.0, 2.7 ~ of incorporated ethylene, Tm = 127 °C, ~Ha, = 63 Jlg.
Example 14 The procedure of Example 1 was followed. 37 g of ethylene were charged. During the polymerization, 112 g of ethyl-ene were metered in. Polymerization was carried out for two hours at 60°C. 53.6 mg (0.100 mmol) of metallocene compound were used. 2.0 kg of random ethylene-propylene copolymer were obtained. The activity of the metallocene was thus 18.7 Dcg of PP/g of metallocane/h or 10.0 kg of PP/mmol of Hf/h.
VZ = 284 cm3/g, Mw = 334000 g/mole, M" = 67000 g/mole, I~"1M" = 5.0, n~2 = 1.0, 7.4 ~ of incorporated ethylene, T~ = 126.5°C, eHm = 64.5 J/g.

Claims

1. A process for the preparation of a propylene copolymer composed of 99.9 to 80.0 mol %, relative to the total polymer, of propylene units and 0.1 to 20.0 mol %, relative to the total polymer, of units which are derived from ethylene or from an olefin with at least 4 carbon atoms of the formula R15-CH=CH-R16, where R15 and R16 are identical or different and denote a hydrogen atom or an alkyl radical having 1 to 28 carbon atoms or R15 and R16 with the carbon atoms bonding them form a ring having 4 to 28 carbon atoms, by polymerizing 50 to 99.5 % by weight, relative to the total amount of monomers, of propylene and 0.5 to 50 % by weight, relative to the total amount of monomers, of at least one representative of the group consisting of ethylene and olefins having at least 4 carbon atoms of the formula R15-CH=CH-R16, where R15 and R16 have the meaning given above, at a temperature of 30°C to 150°C at a pressure of 0.5 to 100 bar in solution, in suspension or in the gas phase in the presence of a catalyst composed of a metallocene and an aluminoxane, wherein the metallocene is a compound of the formula I
in which R1 and R2 are identical or different and denote a hydrogen atom, a C1-C10-alkyl group, a C1-C10-alkoxy group, a C6-C10-aryl group, a C6-C10-aryloxy group, a C2-C10-alkenyl group, a C7-C40-arylalkyl group, a C7-C40-alkylaryl group, a C8-C40-arylalkenyl group or a halogen atom, R3, R4, R5 and R6 are identical or different and denote a hydrogen atom, a halogen atom, a C1-C10-alkyl group, a radical -NR 2 10-, -SR 10-, -OSiR3 10, -SiR-3 10-, or -PR2 10 in which R10 is a C1-C10-alkyl group, a C6-C10-aryl group or if the radical contains Si or P
may also be a halogen atom, or each pair of adjacent radicals R3, R4, R5 or R6 forms a ring with the carbon atoms linking them, R7 is =BR11, =A1R,11. -Ge-. -Sn-, -O-, -S-..=SO, =SO2, =NRII, =CO. =PRII or =P(O)R11 where R11, R12 and R13 are identical or different and denote a hydrogen atom, a halogen atom, a C1-C30-alkyl group, a C1-C10-fluoroalkyl group, a C8-C10-aryl group, a C8-C10-fluoroaryl group, a C1-C40-alkoxy group, a C2-C10-alkenyl group, a C7-C40-arylalkyl group, a C8-C40-arylalkenyl group, a C7-C40-alkyl-aryl group or R11 and R12 or R11 and R13 in each case form a ring with the atoms bonding them, M1 is silicon, germanium or tin, R8 and R9 are identical or different and have the meaning given for R11, m and n are identical or different and are zero, 1 or 2, m plus n being zero, 1 or 2, and the aluminoxane is one of the formula (II) in the instance of the linear type and/or of the formula (III) in the instance of the cyclic type, R14 in the formulae (II) and (III) denoting a C1-C6,-alkyl group and p denoting an integer from 2 to 50.

2. The process as claimed in claim 1, wherein the metallocene is a compound of the formula I in which the radical - ( CR8R9 ) m-R7- (CR8R9)n- denotes -CH2-CH2-, -Ge(CH3)2-, -Si(CH3)2-, -Si(C6H5)2- or -Si(CH3) (C6H5)-.

3. The process as claimed in claim 1, wherein the metallocene is ethylenebisindenylhafnium dichloride or bisindenyldimethylsilylhafnium dichloride.

4. A random propylene copolymer composed of 99.9 to 80.0 mol %, relative to the total polymer, of propylene units and 0.1 to 20.0 mol %, relative to the total polymer, of units which are derived from ethylene or from an olefin with at least 4 carbon atoms of the formula R15-CH=CH-R18 where R15 and R16 are identical or different and denote a hydrogen atom or an alkyl radical having 1 to 28 carbon atoms or R15 and R16 form a ring of 4 to 28 carbon atoms with the atoms bonding them, the said copolymer having an average molecular weight of more than 100000 g/mole, a polydispersity of 2.5 to 5.5 and a sequence length of below 1.25.

5. The use of the propylene copolymer prepared as claimed in claim 1 for the preparation of sheets for thermoforming, and for the blowmolding of hollow articles.