GB1589096A - Process for producing copolymers of ethylene and polyethylenically unsaturated polycyclic hydrocarbons - Google Patents

Description

PATENT SPECIFICATION

( 11) 1 589 096 ( 21) Application No 35802/79 ( 22) Filed 7 July 1977 ( 62) Divided out of No 1 589 095 ( 31) Convention Application No ( 19) 379 ( 32) Filed 16 July 1976 in / ( 33) Italy (IT) ( 44) Complete Specification published 7 May 1981 ( 51) INT CL 3 C 08 F 210/02 4/68 (C 08 F 210/02 232/08 236/20) ( 52) Index at acceptance C 3 P 404 440 454 464 468 474 498 504 508 578 GV C 3 W 213 217 ( 72) Inventors MARIO BRUZZONE ANTONIO CARBONARO ( 54) PROCESS FOR PRODUCING COPOLYMERS OF ETHYLENE AND POLYETHYLENICALLY UNSATURATED POLYCYCLIC HYDROCARBONS ( 71) We, SNAMPROGETTI S P A, an Italian Company, of Corso Venezia 16, Milan, Italy, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:This invention relates to a process for producing copolymers of ethylene and polyethylenically unsaturated polycyclic hydrocarbons.

According to the present invention, there is provided a process for producing a copolymer of ethylene and one or more polyethylenically unsaturated hydrocarbons in which at least one centre of unsaturation belongs to a polycyclic system, which process comprises copolymerizing ethylene and the polyethylenically unsaturated hydrocarbon(s) in the presence of a diluent and of a catalytic system comprising ( 1) one or more vanadium compounds soluble in the reaction medium and in which the valency of vanadium is greater than two, ( 2) one or more aluminium compounds having the general formula Al R 2 X wherein R is an alkyl, cycloalkyl, alkaryl, aralkyl or aryl radical having from 1 to 12 carbon atoms and X is a chlorine or bromine atom, and ( 3) either (a) hexachlorocyclopentadiene or (b) hexachlorocyclopentadiene and thionyl chloride, the copolymerization being effected in a manner such that the units derived from ethylene in the copolymer constitute from 90 to 99 9 % of the total units in the copolymer.

The catalytic systems defined above have a high specific activity in the polymerization of ethylene with at least one of the polyethylenically unsaturated hydrocarbons, to obtain copolymers having a high molecular weight, a random distribution of the monomeric units, the presence of centres of unsaturation in the groups placed externally of the main chain, a high melting point and a high degree of crystallinity.

Copolymers of the aforementioned type can be vulcanised with conventional, 50 sulphur-based compounding compositions to produce cross-linked products similar to the high-density polyethylenes but endowed with mechanical, thermal and chemical properties which are improved relative to 55 conventional copolymers.

One advantage of the present invention is that in the copolymer produced, the residual vanadium, coming from the decomposition of the catalytic system, is pre 60 sent in only very slight amounts even if the conventional purification stage is omitted This affords a considerable simplification of the process, inasmuch as it is possible to recover the copolymer from the 65 reaction slurry, by centrifuging or stripping, and directly to dry it, without the need for the usual washing step.

The diluent employed in the process according to the present invention can be 70 an aromatic or an aliphatic diluent.

Examples of vanadium compounds useful as component ( 1) of the catalytic system of the present invention are halides such as vanadium tetrachloride and vanadyl 75 chloride; alcoholates such as vanadyl triisopropylate; chelates such as vanadium triacetplacetonate and vanadyl diacetylacetonate; and all complexes in general.

Examples of component ( 2) of the cata 80 lytic system are aluminium-diethyl monochloride, aluminium di-isobutyl monochloride and aluminium diethyl monobromide.

The molar ratio between the aluminium 85 compound(s) and vanadium compound(s) is generally high since the vanadium compound is used in very small amounts Such a ratio is usually above 10:1, and is normally in the range from 50:1 to 500:1 90 The molar ratio between the third component ( 3) of the catalytic system and the \ O Ch 00 Ir1 589 096 other two components may vary widely.

More particularly, the ratio of the third component ( 3) to the second component (i.e the aluminium compound(s) is preferably in the range from 1:20 to 1:1.

Preferably, the catalytic system is prepared in the presence of at least one of the monomers which take part in the copolymerisation.

The selection of the type of diluent can be dictated by reasons of the desired molecular weight of the copolymer (as the aliphatic solvents encourage the attainment of higher molecular weights), availability or cost.

Also, the use of a mixture of the two types of hydrocarbons may prove an advantage.

The polymerisation temperature is generally in the range from O C to 120 C; it is usually particularly profitable and appropriate to operate in the range from 20 C to 80 C, a range in which the catalytic system attains maximum efficiency, and in which the use of a cooling system to remove the reaction heat is not required.

The polymerization yields can range from 30,000 to 1,000,000 grams, or more, of copolymer per gram of elemental vanadium employed in the catalytic system.

At least two monomers are employed in the reaction under the conditions indicated hereinabove; one is ethylene, and the other is one or more polycrylic com pounds containing at least two centres of ethylenic unsaturation, one of such centres of unsaturation preferably belonging to the polycyclic system of bicyclo-( 2 2 1)-2heptene The monomers of this second class react in the polymerisation by cleavage of the condensed cyclopentane ring, the remaining unsaturations being left unaffected and outside the polymeric chain.

Examples of such monomers are: 5ethylidene-bicyclo-( 2 2 1)-2-heptene (ethylidenenorbornene); 8-isopropylidenedicyclopentadiene; 5-( 2 ',4 '-dimethyl-penta-1 ',3 'dienyl)-bicyclo-( 2 2 1)-2-heptene (dimethylpentadienyl-norborene) and its isomers; and lbicyclo-( 2 2 1)-3 '-heptenyll -3 ', 5 ', 5 ' -trimethyl-cyclohexa-l,3-dienyl)-methane (norbornenyl trimethyl cyclohexadienylmethane) and its isomers.

The copolymerilization of ethylene and one or more hydrocarbons of the type referred to above as promoted by the catalytic system and under the conditions of the present invention, produces hydrocarbonaceous copolymers which have properties of considerable practical interest.

More particularly, the copolymers having from 99 9 % to 95 % of units derived from ethylene and from 0 1 % to 5 % of units derived from the polyene of the kind referred to above possess a few physical properties, such as the melting point and specific gravity, which differ only slightly from those of a high density polyethylene having the same average molecular weight On the other hand, the presence of centres of un 70 saturation in the side chain and their random distribution both in the interior of the individual macromolecule and among the several chains, permit cross-linked products to be obtained which have physico 75 mechanical, thermal and chemical properties which are positively improved over those of the most satisfactory conventional polyethylenes.

The copolymers the subject of the pre 80 sent invention are particularly reactive under conventional vulcanisation conditions, which are those well known to the skilled practitioner when sulphur and accelerators are employed as the cross 85 linking agents For example, very low contents of units derived from ethylidenenorbornene (from 0 2 to 0 5 molar %) in the copolymer with ethylene are sufficient to obtain vulcanizates with a gel content 90 of more than 80 % When ethylidenenorbornene is present in an amount from 0.5 to 1 molar percent, a gel content of up to 100 % may be obtained Such a result, which is an index of a truly random 95 distribution of the comonomer units, has not hitherto been obtained when using comonomers for ethylene other than those specified for the present invention 100 In the particular case in which isopropylidenedicyclopentadiene is copolymerized with ethylene, there are directly obtained from the polymerization, products which have branches of such a nature as to im 105 part to the molten mass a high viscosity:

this notwithstanding, the product can readily be milled in an open mill and is capable of expanding in a press even if no curing agents are present 110 The copolymers of the present invention are not only suitable for the production of expanded goods, but they can find a use in all those fields in which the properties of shock-resistance and resistance to stress 115 cracking are required concurrently with high values of mechanical stiffness, heat resistance and resistance to chemicals.

Attention is drawn to our Applications Nos 28622/77 (Serial No 1 589095) and 120 7935803 (Serial No 1 589 097) which describe and claim a process similar to that of the present invention except that component ( 3) of the catalytic system is, in the first case, either (a) one or more organic 125 compounds containing the -C C 11 group, or, (b) one or more of such compounds together with hexachlorocyclopentadiene and/or thionyl chloride, and in the second case, thionyl chloride 130 1 589 096

Claims (1)

1. WHAT WE CLAIM IS:-

   1 A process for producing a copolymer of ethylene and one or more polyethylenically unsaturated hydrocarbons in which at least one centre of unsaturation belongs to a polycyclic system, which process comprises copolymerising ethylene and the polyethylenically unsaturated hydrocarbon(s) in the presence of a diluent and of a catalytic system comprising ( 1) one or more vanadium compounds soluble in the reaction medium and in which the valency of vanadium is greater than two, ( 2) one or more aluminium compounds having the general formual AIR 2 X wherein R is an alkyl, cycloalkyl, alkaryl, aralkyl, or aryl radical having from 1 to 12 carbon atoms and X is a chlorine or bromine atom, and ( 3) either (a) hexachlorocyclopentadiene, or (b) hexachlorocyclopentadiene and thionyl chloride, the copolymerisation being affected in a manner such that the units derived from ethylene in the copolymer constitute from 90 to 99 9 % of the total units in the copolymer.

   2 A process according to claim 1, wherein the vanadium compound is selected from vanadium halides, vanadium alcoholates, vanadium chelates and vanadium complexes.

   3 A process according to claim 2, wherein the vanadium compound is selected from vanadium tetrachloride, vanadyl chloride, vanadyl tri-isopropylate, vanadium triacetylacetonate and vanadyl diacetylacetonate.

   4 A process according to claim 1, 2 or 3 wherein the aluminium compound is selected from aluminium diethyl monochloride, aluminium di-isobutyl monochloride and aluminium diethyl monobromide.

   A process according to any preceding claim, wherein the molar ratio of the aluminium compound(s) to the vanadium compound(s) of the catlytic system is greater than 10:1.

   6 A process according to claim 5, wherein the molar ratio of the aluminium compound(s) to the vanadium compound(s) of the catalytic system is from 50:1 to 500:1.

   7 A process according to any preceding claim, wherein the molar ratio of the third component ( 3) to the second component 55 ( 2) of the catalytic system is from 1:20 to 1:1.

   8 A process according to any preceding claim, wherein the copolymerisation is carried out in a diluent selected from ali 60 phatic and aromatic hydrocarbons.

   9 A process according to any preceding claim, wherein the catalytic system is prepared in the presence of at least one of the monomers which take part in the co 65 polymerization.

   A process according to any preceding claim, wherein the copolymerization is carried out at a temperature in the range of from O C to 120 C 70 11 A process according to claim 10, wherein the copolymerization is carried out at a temperature in the range from C to 80 C.

   12 A process according to any preced 75 ing claim, wherein the conditions of the copolymerization are such that the yield of copolymer referred to the vanadium compound is in the range from 30,000 to over 1,000,000 grams of copolymer per 80 gram of elemental vanadium.

   13 A process according to any preceding claim, wherein the copolymerization product is recovered from the reaction slurry by centrifuging or stripping, without 85 any washing step for removing the catalyst residues.

   14 A process according to any preceding claim, wherein the hydrocarbon comprises a bicyclo-( 2 2 1)-2-heptene system 90 A process according to any one of claims 1 to 13, wherein the hydrocarbon is 5-ethylidene-bicyclo-( 2 2 1)-2-heptene (ethylidenenorbornene).

   16 A process according to any one of 95 claims 1 to 13, wherein the hydrocarbon is 8-isopropylidenedicyclopentadiene.

   17 A process according to any one of claims 1 to 13, wherein the hydrocarbon is 5 ( 2 ',4 '-dimethyl-penta-1 ',3 '-dienyl) 100 1 589 096 bicyclo-( 2 2 1)-2-heptene.

   18 A process according to any one of claims 1 to 13, wherein the hydrocarbon is lbicyclo-( 2 2 1)-3 '-heptenyll -( 3 ', 5 ', 5 'trimethyl-cyclohexa-l ',3 '-dienyl) methane (norbornenyl trimethyl -cyclohexadienylmethane).

   19 A process according to any preceding claim, wherein the copolymerization is effected in a manner such that the units derived from ethylene in the copolymer constitute from 95 to 99 9 % of the total units in the copolymer.

   A process according to any preceding claim, which also includes the subsequent step of cross-linking the copolymer, using sulphur and accelerators.

   21 A copolymer whenever produced by a process according to any preceding claim 20 HASELTINE LAKE & CO.

   Chartered Patent Agents 28 Southampton Buildings Chancery Lane London WC 2 A 1 AT -andTemple Gate House Temple Gate Bristol B 51 6 PT -and9 Park Square Leeds L 51 2 LH Printed for Her Majesty's Stationery Office by The Tweeddale Press Ltd, Berwick-upon-Tweed, 1981.

   Published at the Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.