AU608787B2 - Narrow mwd alpha-olefin copolymers - Google Patents

Description

ture of Applicant or Beal of Company and aignatures of its Omficers prescribed by its Articles of Auociation, by .M War A cMaster R istered Patent.Attorney lg~ iiapry Form COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952-69 COMPLETE SPECIFICATION

(ORIGINAL)

608787 Class Application Number: Lodged: Int. Class Complete Specification Lodged: Accepted: Published: Priority Related Art: 0 a 6 eo Name of Applicant: Address of Applicant: Actual Inventor: Address for Service EXXON RESEARCH AND ENGINEERING COMPANY P. O. Box 390, Florham Park, New Jersey 07932, United States of America CHARLES COZEWITH, SHIAW JU and GARY WILLIAM VERSTRATE EDWD. WATERS SONS, 50 QUEEN STREET, MELBOURNE, AUSTRALIA, 3000.

Complete Specification for the invention entitled: NARROW MWD ALPHA-OLEFIN COPOLYMERS The following statement is a full description of this invention, including the best method of performing it known to us 1 a I 1 &ARROW MWD ALPHA-OLEFIN COPOLYMERS 1 Background of the Invention The present invention relates to novel copolymers 3 of alpha-olefins. More specifically, it relates to novel copolymers of ethylene with other alpha-olefins comprised of copolymer chains with compositions which are intramolecular- 7ly heterogeneous and intermolecularly homogeneous, as well 8 as, to a process for making these copolymers and their use in lube oil and elastomer applications.

o e 9 For convenience, certain terms that are repeated o 10 1 throughout the present specification are defined below: so a 11 a. Inter-CD defines the compositional variation, 12 13 in terms of ethylene content, among polymer chains. It is 13 14 expressed as the minimum deviation (analogous to a standard deviation) in terms of weight percent ethylene from the 16 average ethylene composition for a given copolymer sample *a 17 needed to include a given weight percent of the total co- 18 polymer sample which is obtained by excluding equal weight 19 fractions from both ends of the distribution. The deviation 20 need not be symmetrical. When expressed as a single number 21 for example 15% Inter-CD, it shall mean the larger of the 22 positive or negative deviations. For example, for a Gaussian 23 compositional distribution, 95.5% of the polymer is within 24 wt.% ethylene of the mean if the standard deviation is The Inter-CD for 95.5 wt.% of the polymer is 20 wt.% ethylene 26 for such a sample.

27 b. Intra-CD is the compositional variation, in 28 terms of ethylene, within a copolymer chain. It is .expressed 29 as the minimum difference in weight ethylene that exists between two portions of a single copolymer chain, each 31 portion comprising at least 5 weight of the chain.

32 c. Molecular weight distribution (MWD) is a mea- 33 sure of the range of molecular weights within a given co- 34 polymer sample. It is characterized in terms of at least one of the ratios of weight average to number average molecular 36 weight, Mw/Mn, and Z average to weight average molecular 37 weight, Mz/Mw, where: Mw 7 NiMi2 j NiMi "aM i

I

-2- -n Z NiMi and Z Ni 2 z Z NiMi 3 wherein 2 NiMi 2 3 Ni is the number of molecules of weight Mi.

4 d. Viscosity Index is the ability of a lubricating oil to accommodate increases in temperature with 6 a minimum decrease in viscosity. The greater this ability, 7 the higher the V.I.

8 Ethylene-propylene copolymers, particularly elas- 9 tomers, are important commercial products. Two basic types 10 of ethylene-propylene copolymers are commercially available.

11 Ethylene-propylene copolymers (EPM) are saturated compounds 12 requiring vulcanization with free radical generators such as 13 organic peroxides. Ethylene-propylene terpolymers (EPDM) 14 contain a small amount of non-conjugated diolefin, such as o, 15 dicyclopentadiene; 1,4-hexadiene or ethylidene norbornene, 16 which provides sufficient unsaturation to permit vulcaniza- 17 tion with sulfur. Such polymers that include at least two 18 monomers, EPM and EPDM, will hereinafter be collect. i 19 tively referred to as copolymers.

20 These copolymers have outstanding resistance to 21 weathering, good heat aging properties and the ability to be 22 compounded with large quantities of fillers and plasticizers 23 resulting in low cost compounds which are particularly useful 24 in automotive and industrial mechanical goods applications.

Typical automotive uses are tire sidewalls, inner tubes, 26 radiator and heater hose, vacuum tubing, weather stripping 27 and sponge doorseals and Viscosity Index improvers for 28 lubricating oil compositions. Typical mechanical goods uses 29 are for appliance, industrial and garden hoses, both molded and extruded sponge parts, gaskets and seals and conveyor 31 belt covers. These copolymers also find use in adhesives, 32 appliance parts as in hoses. and gaskets, wire and cable and 33 plastics blending.

I m I 3- 1 As can be seen from the above, based on their 2 respective properties, EPM and EPDM find many, varied uses.

3 It is known that the properties of such copolymers which make 4 them useful in .a particular application are, in turn, determined by their composition and structure. For example, 6 the ultimate properties of an EPM or EPDM copolymer are 7 determined by such factors as composition, compositional 8 distribution, sequence distribution, molecular weight, and 9 molecular weight distribution (MWD).

Sao a S 10 The efficiency of peroxide curing depends on com- 11 position. As the ethylene level increases, it can be shown 12 that the "chemical" crosslinks per peroxide molecule in- 13 creases. Ethylene content also influences the rheological 14 and processing properties, because crystallinity, which acts as physical crosslinks, can be introduced. The crystallinity 16 present at very high ethylene contents may hinder proo 0. 17 cessibility and may make the cured product too "hard" at 18 temperatures below the crystalline melting point to be useful 19 as a-rubber.

20 Milling behavior of EPM or EPDM copolymers varies 21 radically with MWD. Narrow MWD copolymers crumble on a mill, 22 whereas broad MWD materials will band under conditions en- 0 Su. 23 countered in normal processing operations. At the shear 24 rates encountered in processing equipment, broader MWD copolymer has a substantially lower viscosity than narrower MWD 26 polymer of the same weight average molecular weight or low 27 strain rate viscosity.

28 Thus, there exists a continuing need for dis- 29 covering polymers with unique properties and compositions.

This is easily exemplified with reference to the area of V.I.

31 improvers for lubricating oils.

32 3 2 A motor oil should not be too viscous at low 3 temperatures so as to avoid serious frictional losses, faci- 34 litate cold starting and provide free oil circulation right Sfrom engine startup. On the other hand, it should not be too 36 thin at working temperatures so as to.avoid excessive engine 37 wear and excessive oil consumption. It is most desirable to n 4 a, a.

ii C 4 II.

4 *1 a0 o .*a 4 employ a lubricating oil which experiences the least viscosity change with changes in temperature.

The ability of a lubricating oil to accommodate increases in temperature with a minimum decrease in viscosity is indicated by its Viscosity Index The greater this ability, the higher the V.I.

Polymeric additives have been extensively used in lubricating oil compositions to impart desirable viscositytemperature characteristics to the compositions. For example, lubricating oil compositions which use EPM or EPDM copolymers or, more generally, ethylene-(C 3

-C

1 8 alpha-olefin copolymers, as V.I. improvers are well known. These additives are designed to modify the lubricating oil so that changes in viscosity occurring with variations in temperature are kept as small as possible. Lubricating oils containing such polymeric additives essentially maintain their viscosity at higher temperatures while at the same time maintaining desirable low viscosity fluidity at engine starting temperatures.

Two important properties (although not the only required properties as is known) of these additives relate to low temperature performance and shear stability. Low temperature performance relates to maintaining low viscosity at very low temperatures, while shear stability relates to the resistance of the polymeric additives to being broken down into smaller chains.

The present invention is drawn to a novel copolymer of ethylene and at least one other alpha-olefin monomer which copolymer is intramolecularly heterogeneous and intermolecularly homogeneous. Furthermore, the MWD of the copolymer is very narrow. It is well known that the breadth of the MWD can be characterized by the ratios of various molecular weight averages. For example, an indication of anarrow MWD in accordance with the present invention is that the ratio of weight to number average molecular weight (Mw/Mn) is less than 2. Alternatively, a ratio of the Zaverage molecular weight to the weight average molecular :1 J3 37 L 5 1 weight (Mz/Mw) of less than 1.8 typifies a narrow MWD in 2 accordaice with the present. invention. It is known that the 3 property.advantages of copolymers in accordance with the 4 present invention are related to these ratios. Small weight fractions of material can disproportionately influence these 6 ratios while not significantly altering the property advan- 7 tages which depend on them. For instance, the presence of a 8 small weight fraction of low molecular weight copolymer can depress Mn, and thereby raise Mw/Mn above 2 10 while maintaining Mz/Mw less than 1.8. Therefore, polymers, in accordance with the present invention, are characterized 12 by having at least one of Mw/Mn less than 2 and Mz/Mw less than 13 1.8. The copolymer comprises chains within which the ratio 14 of the monomers varies along the chain length. To obtain the intramolecular compositional heterogeneity and narrow MWD, Soo, 16 the copolymers in accordance with the present invention are 17 preferably made in a tubular reactor. It has been discovered 18 that to produce such copolymers requires the use of numerous 19 heretofore undisclosed method steps conducted within hereto- 20 fore undisclosed preferred ranges. Accordingly, the present 21 invention is also drawn to a method for making the novel 22 copolymers of the present invention.

.t 23 Copolymers in accordance with the present inven- 24 tion have been found to have improved properties in lubricating oil. Accordingly, the present invention is also drawn 26 to a novel oil additive composition which comprises basestock 27 mineral oil of lubricating viscosity containing an effective 28 amount of a viscosity index improver being copolymer in 29 accordance with the present invention.

6 6 1 Description of the Prior Art 2 Representative prior art dealing with tubular re- 3 actors to make copolymers are as follows: 4 in "Polymerization of ethylene and propylene to amorphous copolymers with catalysts of vanadium oxychloride 6 and alkyl aluminum halides"; E. Junghanns, A. Gumboldt and G.

7 Bier; Makromol. Chem., v. 58 (12/12/62): 18-42, the use of a 8 tubular reactor to produce ethylene-propylene copolymer is o 9 disclosed in which the composition varies along the chain 10 length. More specifically, this reference discloses the o I production in a tubular reactor of amorphous ethylene-propyo12 lene copolymers using Ziegler catalysts prepared from vana- S: 13 dium compound and aluminum alkyl. It is disclosed that at the 14 beginning of the tube ethylene is preferentially polymeriza oo 15 ed, and if no additional make-up of the monomer mixture is 16 made during the polymerization the concentration of monomers o00 o ,oo 17 changes in favor of propylene along the tube. It is further o°°o 18 disclosed that since these changes in concentrations take 0 So 19 place during chain propagation, copolymer chains are pro-.

20 duced which contain more ethylene on one end than at the other 21 end. It is also disclosed that copolymers made in a tube are 22 chemically non-uniform, but fairly uniform as regards mole- 02 S°oe 23 cular weight distribution. Using the data reported in their 24 Figure 17 for copolymer prepared in the tube, it was 0 0 estimated that the Mw/Mn ratio for this copolymer was 1.6, 26 and from their Figure 18 that the intermolecular composi- 27 tional dispersity (Inter-CD, explained in detail below) of 23 this copolymer was greater-than 29 "Laminar Flow Polymerization of EPDM Polymer"; 3J J.F. Wehner; ACS Symposium Series 65 (1978); pp 140-152 31 discloses the results of computer simulation work undertaken 32 to determine the effect of tubular reactor solution poly- 33 merization with Ziegler catalysts on the molecular weight 34 distribution of the polymer product. The specific polymer 33 simulated was an elastomeric terpolymer of ethylene-propy- 36 lene-1,4-hexadiene. On page 149, it is stated that since the monomers have different reactivities, a polymer of varying I I 7 1 composition is obtained as the monomers are depleted. How- 2 ever, whether'the'composition varies inter-or intramolecu- 3 larly is not distinguished. In Table III on page 148, various 4 polymers having Mw/Mn of about 1.3 are predicted. In the third paragraph on page 144, it is stated that as the tube 6 diameter increases, the polymer molecular weight is too low 7 to be.of practical interest, and it is predicted that the 8 reactor will plug. It is implied in the first paragraph on 9 page 149 that the compositional dispersity produced in a tube 10 would be detrimental to product quality.

U.S. 3,681,306 to Wehner is drawn to a process for o 12 producing ethylene/higher alpha-olefin copolymers having o 13 good processability, by polymerization in at least two con- °0 14 secutive reactor stages. According to this reference, this 15 two-stage process provides a simple polymerization process 16 that permits tailor-making ethylene/alpha-olefin copolymers 17 having predetermined properties, particularly those cone 18 tributing to processability in commercial applications such 6" 0 19 as cold-flow, high green strength and millability. According 20 to this reference, the inventive process is particularly 0 C S 21 adapted for producing elastomeric copolymers, such as ethyl- 22 ene/propylene/5-ethylidene-2-norbornene, using any of the 23 coordination catalysts useful for making EPDM. The preferred 24 process uses one tubular reactor followed by one pot reactor.

C 25 However, it is also disclosed that one tubular reactor could 26 be used, but operated at different reaction conditions to 27 simulate two stages. As is seen from column 2, lines 14-20, 28 the inventive process makes polymers of broader MWD 'than 29 those made in a single stage reactor. Although intermediate polymer from the first (pipeline) reactor is disclosed as 31 having a ratio of Mw/Mn of about 2, as disclosed in column 32 lines 54-57, the final polymers produced by the inventive 33 process have an Rw/Mn of 2.4 to 34 U.S. 3,625,658 to Closon discloses a closed circuit tubular reactor apparatus with high recirculation rates of 36 the reactants which can be used to make elastomers of ethylene 37 and propylene. With particular reference to Fig.l, a hinged E• B, 4 S 8 1 support 10 for vertical leg 1 of the reactor allows for 2 horizontal expansion of the bottom leg thereof and prevents 3 harmful deformations due to thermal expansions, particularly 4 those experienced during reactor clean out.

U.S. 4,065,520 to Bailey et al discloses the use of 6 a batch reactor to make ethylene copolymers, including elas- 7 tomers, having broad compositional distributions. Several 8 feed tanks for the reactor are arranged in series, with the S9 feed to each being varied to make the polymer. The products 10 made have crystalline to semi-crystalline to amorphous re- "o 11 gions and gradient changes in between. The catalyst system 12 can use vanadium compounds alone or in combination with 13 titanium compound and is exemplified by vanadium oxy-tri- 14 chloride and diisobutyl aluminum chloride. In all examples titanium compounds are used. In several examples hydrogen 16 and diethyl zinc, known transfer agents, are used. The 17 polymer chains produced have a compositionally disperse o" 18 first length and uniform second length. Subsequent lengths 19 have-various other compositional distributions.

20 In "Estimation of Long-Chain Branching in Ethyl- 21 ene-Propylene Terpolymers from Infinite-Dilution Viscoelas- 22 tic Properties"; Y. Mitsuda, J. Schrag, an.d J. Ferry; J. Appl.

o 23 Pol. Sci., 18, 193 (1974) narrow MWD copolymers of ethylene- 24 propylene are disclosed. For example, in TABLE II on page 198, EPDM copolymers are disclosed which have Rw/Mn of from 26 1.19 to 1.32.

27 In "The Effect of Molecular Wei6ht and Molecular 28 Weight Distribution on the Non-Newtonian Behavior of Ethyl- 29 ene-Propylene-Diene Polymers; Trans. Soc. Rheol.', 14, 83 (1970); C.K. Shih, a whole series of compositionally homo- 31 geneous fractions were prepared and disclosed. For example, 32 the data in TABLE I discloses polymer Sample B having a high 33 degree of homogeneity. Also, based on the reported data, the 34 MWD of the sample is very narrow. However, the polymers are not disclosed as having intramolecular dispersity.

36 Representative prior art dealing with ethylen~- 37 alpha-olefin copolymers as lubricating oil additives are as u6T 9 1 follows: 2 3,697,429 to Engel et al discloses a blend of 3 ethylene-propylene copolymers having different ethylene con- 4 tents, a first copolymer of 40-83 wt.% ethylene and Mw/Mn less than about 4.0 (preferably less than 2.6, e.g. 2.2) 6 and a second copolymer of 3-70 wt.% ethylene and Mw/Rn less 7 than 4.0, with the content of the first differing from the 8 second by at least 4 wt.% ethylene. These blends, when used 0o 9 as V.I. improvers in lubricating oils, provide suitable low ojob 10 temperature viscosity properties with minimal adverse inter- 0 11 action between the oil pour depressant and the ethyleneo" 12 propylene copolymer.

oooo 13 t.S. 3,522,180 discloses copolymers of ethylene o 14 and propylene having a number average molecular weight of 10,000 to 40,000 and a propylene content of 20 to 70 mole 16 percent as V.I. improvers in lube oils. The preferred Mw/M n 17 of these copolymers is less than about o 18 U.S. 3,691,078 to Johnston et al discloses the use 19 of ethylene-propylene copolymers containing 25-55 wt.% ethy- D 20 lene which have a pendent index of 18-33 and an average Od 21 pendent size not exceeding 10 carbon atoms as lube oil 22 additives. The Mw/Mn is less than about 8. These additives OO, 23 impart to the oil good low temperature properties with o o0 So: 24 respect to viscosity without adversely affecting ponr point depressants.

26 U.S. 3,551,336 to Jacobson et al discloses the use 27 of ethylene copolymers of 60-80 mole ethylene, having no 28 more than 1.3 wt.% of a polymer fraction which is insoluble 29 in normal decane at 55 0 C as an oil additive. Minimization of this decane-insoluble fraction in the polymer reduces the 31 tendency of the polymer to form haze in the oil, which-haze 32 is evidence of low temperature instability probably caused by 33 adverse interaction with pour depressant additives. The 34 Mw/Mn of these copolymers is "surprisingly narrow" and is less than about 4.0, preferably less than 2.6, 2.2.

X

f I 1 i'I 10 1 Brief Description of the Drawings 2 The accompanying drawings depict, for illustration 3 purposes only, processes embodied by the present invention, 4 wherein: Fig 1 is a schematic representation of a process 6 for producing polymer in accordance with the present inven- 7 tion, 8 Fig 2 schematically illustrates how the process 9 depicted in Fig 1 can be integrated into a lube oil additive 10 process, 11 Fig 3 is a graphical illustration of a technique 12 for determining Intra-CD of a copolymer, 13 Fig 4 graphically illustrates various copolymer ,14 structures that can be attained using processes in accordance with the present invention, 16 Fig 5 is a graphic representation of polymer con- 17 centration vs. residence time for consideration with Example 18 2 herein, and 19 Fig 6 is a graphic representation of intramolecular compositional dispersity (Intra-CD) of copolymer chains made 21 with additional monomer feeds downstream of the reactor inlet 22 as in Example 3.

tc 23 24 Detailed Description of the Invention As already noted above, the present invention is 26 drawn to novel copolymer of ethylene and at least one other 27 alpha-olefin monomer which copolymer is intramolecularly 28 heterogeneous and intermolecularly homogeneous and has an 29 MWD characterized by at least one of Mw/Mn of less than 2 and Mz/Mw of less than 1.8. More specifically, copolymer in 31 accordance with the present invention comprises intramole- 32 cularly heterogeneous chains wherein at least two portions of 33 an individual intramolecularly heterogeneous chain, each 34 portion comprising at least 5 weight percent of the chain, differ in composition from one another by at least 5 weight 36 percent ethylene, wherein the intermolecular compositional 37 dispersity of the polymer is such that 95 wt.% of the polymer

I-

11 1 chains have a composition 15% or less different in ethylene 2 from the average weight percent ethylene composition, and 3 wherein the copolymer is characterized by at least one of a 4 ratio of Mw/Mn of less than 2 and a ratio of Mz/Mw of less than 1.8.

6 Since the present invention is considered to be 7 most preferred in the context of ethylene-propylene (EPM) or 8 ethylene-propylene-diene (EPDM) copolymers, it will be des- 9 cribed in detail in the context of EPM and/or EPDM.

a 1 0 Copolymer in accordance with the present invention 11 is preferably made in a tubular reactor. When produced in a 04 04

S

a 12 tubular reactor with monomer feed only at the tube inlet, it .o 13 is known that at the beginning of the tubular reactor ethyo O 14 lene, due to its high reactivity, will be preferentially polymerized. However, the concentration of monomers changes 16 along the tube in favor of propylene as the ethylene is Uo 17 depleted. The result is copolymer chains which are higher in o 18 ethylene concentration in the chain segments grown near the 94 19 reactor inlet (as defined at the point at which the poly-.

20 merization reaction commences), and higher in propylene 5,44 ;21 concentration in the chain segments formed near the reactor 22 outlet. An illustrative copolymer chain of ethylene-propy- 23 lene is schematically presented below with E representing 24 ethylene constituents and P representing propylene constituents in the chain: 26 1 2 3 4 27egment:

P--P

28 29 As can be seen from this illustrative schematic chain, the far left-hand segment thereof represents that portion 31 of the chain formed at the reactor inlet where the reaction 32 mixture is proportionately richer in the more reactive con- 33 stituent ethylene. This segment comprises four ethylene 34 molecules and one propylene molecule. However, as subsequent segments are formed from left to right with the more reactive 36 ethylene being depleted and the reaction mixture propor- 37 tionately increasing in propylene concentration, the sub- ICII-iCI- 1 12 1 sequent chain segments become more concentrated in propy- 2 lene. The resulting chain is intramolecularly heterogen- 3 eous.

4 In the-event that more than two monomers are used, in the production of EPDM using a diene termonomer, for 6 purposes of describing the present invention all properties 7 related to homogeneity and heterogeneity will refer to the 8 relative ratio of ethylene to the other monomers in the chain.

9 The property, of the copolymer discussed herein, related to intramolecular compositional dispersity (compositional var- °o 11 iation within a chain) shall be referred to as Intra-CD, and 12 that related to intermolecular compositional dispersity 0 o 13 (compositional variation between chains) shall be referred 14 to as Inter-CD.

S° 15 For copolymers in accordance with the present in- 0 .1 vention, composition can vary between chains as well as along 17 the length of the chain. An object of this invention is to 18 minimize the amount of interchain variation. The Inter-CD 0 19 can be characterized by the difference in composition between 0° 20 some fraction of the copolymer and the average composition, 0 21 as well as by the total difference in composition between the S22 copolymer fractions containing the highest and lowest quan- 23 tity of ethylene. Techniques for measuring the breadth of the :oo 24 Inter-CD are known as illustrated by Junghanns et al wherein 000 25 a p-xylene-dimethylformamide solvent/non-solvent was used to 0:0o0% 26 fractionate copolymer into fractions of differ.-ig inter- 27 molecular composition. Other solvent/non-solvent systems 28 can be used such as hexane-2-propanol, as will be discussed 29 in more detail below.

The Inter-CD of copolymer in accordance with the 31 present invention is such that 95 wt.% of the copolymer chains 32 have an ethylene composition that differs from the average 33 weight percent ethylene composition by 15 wt.% or less. The 34 preferred Inter-CD is about 13% or less, with the most 3 preferred being about 10% or less. In comparison, Junghanns 36 et al found that their tubular reactor copolymer had an Inter- 37 CD of greater than 15 weight i. -i ;i i -I 13 1 Broadly, the Intra-CD of copolymer in accordance 2 with the present invention is such that at least two portions 3 of an individual intramolecularly heterogeneous chain, each 4 portion comprising at least 5 weight percent of the chain, differ in composition from one another by at least 5 weight 6 percent ethylene. Unless otherwise indicated, this property 7 of Intra-CD as referred to herein is based upon at least two 8 5 weight percent portions of copolymer chain. The Intra-CD 9 of copolymer in accordance with the present invention can be such that at least two portions of copolymer chain differ by 11 at least 10 weight percent ethylene. Differences-of at least 12 20 weight percent, as well as, of at least 40 weight percent 13 ethylene are also considered to be in accordance with the 14 present invention.

15 The experimental procedure for determining Intra- 16 CD is as follows. First the Inter-CD is established as 17 described below, then the polymer chain is broken into 18 fragments along its contour and the Inter-CD of the fragments Soo 19 is determined. The difference in the two results is due to 20 Intra-CD as can be seen in the illustrative example below.

21 Consider a heterogeneous sample polymer containing 22 30 monomer units. It consists of 3 molecules designated A, o. 23 B, C.

24 A EEEEPEEEPEEEPPEEPPEPPPEPPPPPPP 25 B EEEEEPEEEPEEEPPEEEPPPEPPPEEPPP 26 C EEPEEEPEEEPEEEPEEEPPEEPPPEEPPP 27 Molecule A is 36.8 wt. ethylene, B is 46.6%,'and 28 C is 50% ethylene. The average ethylene content for the 29 mixture is 44.3%. For this sample the Inter-CD is such that the highest ethylene polymer contains 5.7% more ethylene than 31 the average while the lowest ethylene content polymer con- 32 tains 7.5% less ethylene than the average. Or, in other 33 words,'100 weight of the polymer is within and 34 ethylene about an average of 44.3%. Accordingly, the Inter- CD is 7.5% when the given weight of the polymer is 100%. The 36 distribution may be represented graphically as by curve 1 in 37 Figure 3.

14 00 0 a too 0 0 1 a I If the chains are broken into -fragments, there will be a new Int*er-CD. For simplicity, consider first breaking only molecule A into fragments shown by the slashes as f ollows:

EBEEP/EEEPE/EEPPE/EPPEP/PPEPP/PPPPP

Portions of 72. 72. 50%, 30. 14. 3% and 0% ethylene are obtained. If molecules B and C are similarly broken and the weight fractions of similar composition are grouped the new Inter-CD shown by curve 2 in Figure 3 is obtained. The difference between the two curves in the figure is due to Intra-CD.

Cons ideration of such data, especially near the end point ranges, demonstrates that for this samiole at least of the chain contour represented by the cumulative weight range differs in composition from another section by at least 15% ethylene shown as the difference between the two curves. The difference in composition represented by (b) cannot be intermolecular. if it were, the separation process for -the original polymer would have revealed the higher ethylene contents seen only for the degraded chain.

The compositional differences shown by and (d) in the figure between original and fragpented chains give mini-mum values for Intra-CD. The Intra-CD must be at least that great, for chain sections have been isolated which are the given difference in composition or from the highest or lowest composition polymer isolated from the original. We know in this example that the original polymer represented at had sections of 72.7% ethylene and 0% ethylene in the same chain. It is highly likely th.-I-Zt due to the inefficiency of the fractionation piocess any-real polymer with Intra-CD examined will have sections of lower or higher ethylene connected along its contour than that shown by the end points of the fractionation of the original polymer. ThuA, this procedure determines a lower bound for Intra-CD. To enhance the detection, the original whole polymer can'be fractionated separate molecule A from mole'cule B from molecule C in the hypothetical example) with 37

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15 1 these fractions refractionated until they show no (or less) 2 Inter-CD. Subsequent fragmentation of this intermolecularly 3 homogeneous fraction now reveals the total Intra-CI. In 4 principle, for the example, if molecule A were isolated, fragmented, fractionated and analyzed, the Intra-CD for the 6 chain sections would be 72.7-0% 72.7% rather than 72.7-50% 7 22.7% seen by fractionating the whole mixture of molecules 8 A, B, and C.

9 In order to determine the fraction of a polymer which is intramolecularly heterogeneous in a mixture of S. o. 11 polymers combined from several sources the mixture must be 12 separated into fractions which show no further heterogenity S13 upon subsequent fractionation. These fractions are oe as S* 14 subsequently fractured and fractionated to reveal which are! 15 heterogeneous.

16 The fragments into which the original polymer is 17 broken should be large enough to avoid end effects and to give 18 a reasonable opportunity for the normal statistical distri- 19 bution of segments to form over a given monomer conversion .°e0"o 20 range in the polymerization. Intervals of ca 5 weight of 21 the polymer are convenient. For example, at an average 22 polymer molecular weight of about 10 5 fragments of ca 5000 23 molecular weight are appropriate. A detailed mathematical 24 analysis of plug flow or batch polymerization.indicates that o, 25 the rate of change of composition along the polymer chain tt«< 26 contour will be most severe at high ethylene conversion near 27 the end of the polymerization. The shortest fragments are 28 needed here to show the low propylene content 'sections.

29 The best available technique for determination of compositional dispersity for non-polar polymers is solvent/- 31 non-sdlvent fractionation which is based on the thermo- 32 dynamics of phase separation. This technique is described in 33 "Polymer Fractionaticn", M. Cantow editor, Academic 1967, 34 p.341 ff and in H. Inagaki, T. Tanaku, Developments in Polymer Characterization, 3, 1 (1982). These are incorporated herein 36 by reference.

37 For non-crystalline copolymers of ethylene and 38 propylene, molecular weight governs insolubility more than 16 1 does composition in a solvent/non-solvent solution. High 2 molecular weight polymer is less soluble in a given solvent 3 mix. Also, there is a systematic correlation of molecular 4 weight with ethylene content for the polymers described herein. Since ethylene polymerizes much more rapidly than 6 propylene, high ethylene polymer also tends to be high in 7 molecular weight. Additionally, chains rich in ethylene tend 8 to be less soluble in hydrocarbon/polar non-solvent mixtures 9 than propylene-rich chains. Thus the high molecular weight, high ethylene chains are easily separated on the basis of 11 thermodynamics.

12 A fractionation procedure is as follows: Un- 13 fragmented polymer is dissolved in n-hexane at 23 0 C to form o 14 ca a 1% solution (1 g polymer/100 cc hexane). Isopropyl S. 15 alcohol is titrated into the solution until turbidity appears o 16 at which time the precipitate is allowed to settle. The 17 supernatant liquid is removed and the precipitate is dried by 18 pressing between Mylar® (polyethylene terphthalate) film at 0 I or 19 150 0 C. Ethylene content is determined'by ASTM method D-3900.

Titration is resumed and subsequent fractions are recovered 21 and analyzed until 100% of the polymer is collected. The 22 titrations are ideally controlled to produce fractions of 0*4054 0 23 10% by weight of the original polymer especially at the 24 extremes of composition.

0 0 0" 25 To demonstrate the breadth of the distribution, the o 26 data are plotted as ethylene versus the cumulative weight 27 of polymer as defined by the sum of half the weight of the 28 fraction of that composition plus the total weight of the 29 previously collected fractions.

Another portion of the original polymer is broken 31 into fragments. A suitable method for doing this is by 32 thermal degradation according to the following procedure: In 33 a sealed container in a nitrogen-purged oven, a 2mm thick 34 layer of the polymer is heated for 60 minutes at 3300C. This should be adequate to reduce a 10 5 molecular weight polymer 36 to fragments of ca 5000 molecular weight. Such degradation 37 does not change the average ethylene content of the polymer.

17 44 4 *44 a.* 4 4o ai 4 4 *404 a 4 Thi.s polymer is fractionated by the same procedure..asthe high molecular weight precursor. Ethylene content is measured, as well as molecular weight on selected fractions.

Ethylene content is measured by ASTM-D3900 for ethylene.-propylene copolymers between 35 and 85 ethylene. Above 85% ASTM-D2238 can be used to obtain methyl group concentrations which are related to percent ethylene in an unambiguous manner for ethylene-propylene copolymers. When comonomers other than-propy.lene are employed no ASTM tests covering a wide range of ethylene contents are available, however, proton and carbon 13 nuclear magnetic resonance can be employed to determine the composition of such polymers.

These are absolute techniques .requiring no calibration when operated such that all nucleii contribute equally to the spectra. For ranges not covered by the ASTM tests for ethylene-propylene copolymers, these nuclear magnetic resonance methods can also be used.

Molecular weight and molecular weight distribution are measured using a Waters 150 gel permeation chromatograph equipped ;ith a Chromatix KMX-6 on-line light scattering photometer. The system is used at 1350C with 1,2,4 trichlorobenzene as mobile phase. Showdex (Showa-Denko America, Inc.) polystyrene gel columns 802, 803, 804 and 805 are used. This technique is discussed in "Liquid Chromatography of Polymers and Related Materials III", J. Cazes editor.

Marcel Dekker, 1981, p. 207 (incorporated herein by reference). No corrections for column spreading are employed; however, data on generally accepted standards, National Bureau of Standards Polyethene 1484 and anionically produced hydrogenated polyisoprenes (an alternating ethylene-.

propylene copolymer) demonstrate that such corrections on Rw/Mn or Mz/Mw'are less than .05 unit. Rw/Mn is calculated from an elution time-molecular weight relationship whereas Mz/Mw is evaluated using the light scattering photometer.

The numerical analyses can be performed using the commercially available computer software GPC2, MOLWT2 available from LDC/Milton Roy-Riviera Beach, Florida.

36 37

LL

i; i. 18 1 As already noted, copolymers.in-accordance with the 2 present invention are comprised of ethylene and at least one 3 other alpha-olefin. It is believed that such alpha-olefins 4 could include those containing 3 to 18 carbon atoms, e.g., propylene, butene-1, pentene-l, etc. Alpha-olefins of 3 to 6 6 carbons are preferred due to economic considerations. The 7 most preferred copolymers in accordance with the present 8 invention are those comprised of ethylene and propylene or 9 ethylene, propylene and diene As is well known to those skilled in the art, 11 copolymers of ethylene and higher alpha-olefins such as S 12 propylene often include other polymerizable monomers. Typi- Sn 13 cal of these other monomers may be non-conjugated dienes such 14 as the following non-limiting examples: a. straight chain acyclic dienes such as: 1,4- 16 hexadiene; 1,6-octadiene; 17 b. branched chain acyclic dienes such as: 18 methyl-1, 4-hexadiene; 3,7-dimethyl-1,6-octa- *19 diene; .3,7-dimethyl-1,7-octadiene and the mixed 20 isomers of dihydro-myrcene and dihydroocinene; 21 c. single ring alicyclic dienes such as: 1,4- OVL 22 cyclohexadiene; 1,5-cyclooctediene; and o t23 cyclododecadiene; 24 d. multi-ring alicyclic fused and bridged ring 44 25 dienes such as: tetrahydroindene; methyltetrahyu 26 droindene; dicyclopentadiene; bicyclo-(2,2,1) 27 hepta-2,5-diene; alkenyl, alkylidene, cycloalkenyl 28 and cycloalkylidene norbornenes such as 29 lene-2-norbornene (MNB), 5-ethylidene-2-norbornene (ENB), 5-propyl-2-norbornene, 31 dene-2-norbornene, 5-(4-cyclopentenyl) -2- 32 norbornene; 5-cyclohexylidene-2-norbornene.

33 Of the.non-conjugated dienes typically use to 34 prepare these copolymers, dienes containing at least one of the double bonds in a strained ring are preferred. The most 36 preferred diene is 5-ethylidene-2-norbornene (ENB). The 37 amount of diene (wt. basis) in the copolymer could be from Li ii i -1 -r r- I I 19 1 about 0% to. 20% with 0% to 15% being preferred. The most 2 preferred range is 0% to 3 As already noted, the most preferred copolymer in 4 accordance with the present invention is ethylene-propylene or ethylene-propylene-diene. In'either event, the average 6 ethylene content of the copolymer could be as low as about 7 on a weight basis. The preferred minimum is about 25%. A more 8 preferred minimum is about 30%. The maximum ethylene content 9 could be about 90% on a weight basis. The preferred maximum is about 85%, with the most preferred being about 11. The molecular weight of copolymer made in accor- 12 dance with the present invention can vary over a wide range.

%t 00 413 It is believed that the weight average molecular weight could 14 be as low as about 2,000. The preferred minimum is about 15 10,000. The most preferred minimum is about 20,000. It is o e 16 believed that the maximum weight average molecular weight 17 could be as high as about 12,000,000. The preferred maximum 18 is about 1,000,000. The most preferred maximum is about 19 750,000.

20 Another feature of copolymer made in accordance 21 with the present invention is that the molecular weight 22 distribution (MWD) is very narrow, as characterized by at 23 least one of a ratio of Mw/Mn of less than 2 and a ratio of 24 Rz/Mw of less than 1.8. As relates to E2M and EPDM, some 25 typical advantages of such copolymers having narrow MWD are 26 greater resistance to shear degradation, and when compounded 27 and vulcanized, faster cure and better physical properties 28 than broader MWD materials. Particularly for oil. additive 29 applications, the preferred copolymers have Mw/Mn less than abc t 1.6, with less than about 1.4 being most preferred. The 31 preferred Mz/Mw is less than about 1.5, with less than about 32 1.3 being most preferred.

33 Processes in accordance with the present invention 34 produce copolymer by polymerization of a reaction mixture comprised of catalyst, ethylene and at least one additional 36 alpha-olefin monomer. Solution polymerizations are pre- 37 ferred.

20 1 Any known solvent for the reaction mixture that is 2 effective for the purpose can be used in conducting solution 3 polymerizations ir accordance with the present invention.

4 For example, suitable solvents would be hydrocarbon solvents such as aliphatic, cycloaliphatic and aromatic hydrocarbon 6 solvents, or halogenated versions of such solvents. The 7 preferred solvents are C 12 or lower, straight chain or 8 branched chain, saturated hydrocarbons, C 5 to C 9 saturated 9 alicyclic or aromatic hydrocarbons or C 2 to C 6 ghalogenated hydrocarbons. Most preferred are C 12 or lower, straight I 11 chain or branched chain hydrocarbons, particularly hexane.

12 Nonlimiting illustrative examples of solvents are butane, 0 0 13 pentane, hexane, heptane, cyclopentane, cyclohexane, cyclo- 14 heptane, methyl cyclopentane, methyl cyclohexane, isooctane, benzene, toluene, xylene, chloroform, chlorobenzenes, tet- S° 16 rachloroethylene, dichloroethane and trichloroethane.

17 These processes are carried out in a mix-free S(.e ree- kshcceer .c.s kere nkerore- Ae.f&eA o 18 reactor system, which is one in which substantially no mixing .o 19 occurs between portions of the reaction mixture that contain o QQO polymer chains initiated at different times. Suitable re- 21 actors are a continuous flow tubular or a stirred batch 22 reactor. A tubular reactor is well knowh and is designed to 23 minimize mixing of the reactants in the direction of flow. As 24 a result, reactant concentration will vary along the reactor 25 length. In contrast, the reaction mixture in a continuous 26 flow stirred tank reactor (CFSTR) is blended with the incom- 27 ing feed to produce a solution of essentially uniform-com- 28 position everywhere in the reactor. Consequently, the grow- 29 ing chains in a portion of the reaction mixture will have a variety of ages and thus a single CFSTR is not suitable for 31 the process of this invention. However, it is well known that 32 3 or more stirred tanks in series with all of the catalyst fed 33 to the first reactor can approximate the performance of a 34 tubular reactor. Accordingly, such tanks in series are 35 considered to be in accordance with the present invention.

36 A batch reactor is a suitable vessel, preferably S37 equipped with adequate agitation, to which the catalyst, Li i i i -1 L I>31 21 0 0 000 6 0 00 01 00 0 0 0 000*00 0 9 9'I 0 100 O 00 6 04 0 00P 0 0 0 0 001 00 0 0 solvent, and monomer are added at the start of the polymerization. The charge of reactants is then left to polymerize for a time long enough to produce the desired product.

For economic reasons, a tubular reactor is preferred to a batch reactor for carrying out the processes'of this invention.

In addition to the importance of the reactor system to make copolymers in accordance with the present invention, the polymerization' should be conducted such that: a. the catalyst system produces essentially one active catalyst species, b. the reaction mixture is essentially free of chain transfer agents, and c. the polymer chains are essentially all initiated simultaneously, which is at the same time for a batch reactor or at the same point along the length of the tube for a tubular reactor.

The desired polymer can be obtained if additional solvent and reactants at least one of the ethylene, alpha-olefin and diene) are added either along the length of a tubular reactor or during the course of polymerization in a batch reactor. Operating in this fashion may be desirable in certain circumstances to control the polymerization rate or polymer composition. However, it is necessary to add essentially all.of the catalyst at the inlet of the tube or at the onset of batch reactor operation to meet the requirement that essentially all polymer chains are initiated simultaneously.

Accordingly, processes in accordance with the present invention are carried out: in at least one mix-free reactor, using a catalyst system that produces essentially one active catalyst species, using at least one reaction mixture which is essentially transfer agent-free, and in such a manner and under conditions sufficient to initiate propagation of essentially all'polymer 4 I 22 0 0 oo 0 o o 0 0 0 o0 01 O o 0 0 0 0 0 0

A

0 000 O 0 0 0a 0Q00 0 0 0 I0 00 00 0 000 ao a PO 0 9 chains simultaneously.

Since the tubular reactor is the preferred reactor system for carrying out processes in accordance with the present invention, the following illustrative descriptions and examples are drawn to that system, but-will applyto other reactor systems as will readily occur to the artisan having the benefit of the present disclosure.

In practicing processes in accordance with the present invention, use is preferably made of at least one tubular reactor. Thus, in its simplest form, such a process would make use of but a single reactor. However, as would readily occur to the artisan having the benefit of the present disclosure, more than one:reactor could be used, either in parallel for economic reasons, or in series with multiple monomer feed to vary intramolecular composition.

For example, various structures can be prepared by adding additional monomer(s) during the course of the polymerization, as shown in Fig.4, wherein composition is plotted versus position along the contour length of the chain. The Intra-CD of curve 1 is obtained by feeding all of the monomers at the tubular reactor inlet or at the start of a batch reaction. In comparison, the Intra-CD of curve 2 can be made by adding additional ethylene at a point along the tube or, in a batch reactor, where the chains have reached about half their length. The Intra-CD's of Curve 3 requires multiple feed additions. The Intra-CD of curve 4 can be formed if additional comonomer rather than ethylene is added. This structure permits a whole ethylene composition range to be omitted from the chain. In each case, a third or more comonomers may be added.

The composition of the catalyst used to produce alpha-olefin copolymers has a profound effect on copolymer product properties such as compositional dispersity and MWD.

The catalyst utilized in practicing processes in accordance with the present invention should be such as to yield essentially one active catalyst species in the reaction mixture. More specifically, it should yield one primary I, 23 1 active catalyst species which provides for substantially all 2 of the polymerization reaction. Additional active catalyst 3 species could be present, provided the copolymer product is 4 in accordance with the present invention, narrow MWD and Inter-CD. It is believed that such additional active 6 catalyst species could provide as much as 35% (weight) of the 7 total copolymer. Preferably, they should account for about 8 10% or less of the copolymer. Thus, the essentially one 9 active species should provide for at least 65% of the total copolymer produced, preferably for at least 90% thereof. The 11 exteift to which a catalyst species contributes to the 12 polymerization can be readily determined using the below- 13 described techniques for characterizing catalyst according S' 14 to the number of active catalyst species.

15 Techniques for characterizing catalyst according 16 to the number of active catalyst species are within the skill S60, 17 of the art, as evidenced by an article entitled "Ethylene- 18 Propylene Copolymers. Reactivity Ratios, Evaluation and 19 Significance", C. Cozewith and G. Ver Strate, Macromole- 20 cules, 4, 482 (1971), which is incorporated herein by ref- 21 erence.

22 It is disclosed by the authors that copolymers made 23 in a continuous flow stirred reactor should have an MWD t 24 characterized by Mw/Mn=2 and a narrow Inter-CD when one active catalyst species is present. By a combination of 26 fractionation and gel permeation chromatography (GPC) it is 27 shown that for single active species catalysts the composi- 28 tions of the fractions vary no more than about the average 29 and the MWD (weight to number average ratio) for these samples approaches two It is this latter characteristic (Mw/Mn 31 of about 2) that is deemed the more important in identifying 32 a single active catalyst species. On the other hand, other 33 catalysts gave copolymer with an Inter-CD greater than 34 about the average and multi-modal MWD often with Mw/Mn greater than 10. These other'catalysts are deemed to have 36 more than one active species.

37 Catalyst systems to be used in carrying out pro- 24 1 cesses in accordance with the present invention may be 2 Ziegler catalysts, which may typically include: 3 a compound of a transition metal, a metal 4 of Groups I-B, III-B, IVB, VB, VIB, VIIB and VIII of the Periodic Table, and 'an organometal compound of a metal 6 of Groups I-A, II-A, II-B and III-A of the Periodic Table.

7 The preferred catalyst system in practicing pro- 8 cesses in accordance with the present invention comprises 9 hydrocarbon-soluble vanadium compound in which the vanadium valence is 3 to 5 and organo-aluminum compound, with the S11 proviso that the catalyst system yields essentially one *'04 12 active catalyst species as described above. At least one of 0' °13 the vanadium compound/organo-aluminum pair selected must 14 also contain a valence-bonded halogen.

I In terms of formulas, vanadium compounds useful in "o o 16 practicing processes in accordance with the present inven- 17 tion could be: 18

O

19 I (1) 20 VClx(OR)3-x 21 where x 0-3 and R a hydrocarbon radical; S«*0 22 0 23 VC1 4 24 25 VO(AcAc) 2 26 where AcAc acetyl acetonate; 27 28 V(AcAc) 3 29 30 VOCx(AcAc)3-x, (2) 31 where x 1 or 2; and 32 33 VC13-nB, 34 where n 2-3 and B Lewis base capable of making 3 hydrocarbon-soluble complexes with VCl 3 such as tetrahydro- 36 furan, 2-methyl-tetrahydrofuran and dimethyl pyridine.

37

Y

25 1 In formula 1 above,. R preferably represents a.C 1 to 2 C1 0 aliphatic, alicyclic or aromatic hydrocarbon radical 3 such as ethyl (Et);-phenyl, isopropyl, butyl, propyl, n- 4 butyl, i-butyl, t-butyl, hexyl, cyclohexyl, octyl, naphthyl, etc. Non-limiting, illustrative examples of formula-(1) and 6 compounds are vanadyl trihalides, alkoxy halides and 7 alkoxides such as VOC1 3 VOC1 2 (OBu) where Bu butyl, and 8 VO(OC2H5) 3 The most preferred vanadium compounds are VCl 4 9 VOC1 3 and VOC1 2

(OR).

As already noted, the co-catalyst is preferably 11 organo-aluminum compound. In terms of chemical formulas, 4 f12 these compounds could be as follows: 13 A1R 3 Al(OR' )R 2 :r,0 14 Al R 2 C1, R 2 Al-O-A1R 2 AlR'RC1 AIR 2 1 16 A1 2

R

3 C1 3 and o 17 AlRC1 2 18 where R and R' represent hydrocarbon radicals, the ao 19 same or different, as described above with respect to the 0 20 vanadium compound formula. The most preferred organo- 4 ti 21 aluminum compound is an aluminum alkyl sesquichloride such as 22 Al 2 Et 3 Cl 3 or A1 2 (iBu) 3 C1 3 23 In terms of performance, a catalyst system com- 24 prised of VC1 4 and A1 2

R

3 C1 3 preferably where R is ethyl, has been shown to be particularly effective. For best catalyst 26 performance, the molar amounts of catalyst components added 27 to the reaction mixture should provide a molar ratio of 28 aluminum/vanadium (A1/V) of at least about 2. The preferred 29 minimum Al/V is about 4. The maximum Al/V is based primarily on the considerations of catalyst expense and the desire to 31 minimize the amount of chain transfer that may be caused by 32 the organo-aluminum compound (as explained in detail below).

33 Since, as is known certain organo-aluminum compounds act as 3chain transfer agents, if too much is present in the reaction mixture the Mw/Mn of the copolymer may rise above 2. Based 36 on these considerations, the maximum Al/V could be about. however, a miximum of about 17 is more preferred. The most preferred being about 10% or less. In comparison,. junghanns et al found that their tubular reactor copolymer had an Inter- CD of greater than 15 weight Ii. *71 I 1 26 Ir t S 0 o o 0 6 o 0o o o0 6 0 0 0 00 0 *O II tI t~ preferred maximum is about Chain.transfer agents for the Ziegler-catalyzed polymerization of alpha-olefins are well known and are illustrated, by way of example, by hydrogen or diethyl zinc for the production of EPM and EPDM. Such agents are very commonly used to control the molecular weight of EPM and EPDM produced in continuous flow stirred r-actors. For the essentially single active species Ziegler catalyst systems used in accordance with the present invention, addition of chain transfer agents to a CFSTR reduces the polymer molecular weight but does not affect the molecular weight distribution.

On the other hand, chain transfer reactions during tubular reactor polymerization in accordance with.the present' invention broaden polymer molecular weight distribution and Inter-CD. Thus the presence of chain transfer agents in the reaction mixture should be minimized or omitted altogether.

Although difficult to generalize for all possible reactions, the amount of chain transfer agent used should be limited to those amounts that provide copolymer product in accordance with the desired limits as regards MWD and compositional dispersity. It is believed that the maximum amount of chain transfer agent present in the reaction mixture could be as high as about 0.2 mol/mol of transition metal, e.g., vanadium, again provided that the resulting copolymer product is in accordance with the desired limits as regards MWD and compositional dispersity. Even in the absence of added chain transfer agent, chain transfer reactions can occur because propylene and the organo-aluminum cocatalyst can also act as chain transfer agents. In general, among the organo-aluminum compounds that in combination with the vanadium compound yield just one active species, the organoaluminum compound that gives the highest copolymer molecular weight at acceptable catalyst activity should be chosen.

Furthermore, if the Al/V ratio has an effect on the molecular weight of copolymer product, that Al/V should be used which gives the highest molecular weight also at acceptable catalyst activity. Chain transfer with propylene can best be r- 27 1 limited by avoiding excessive temperature during-the poly- 2 merization as described below.

3 Molecular weight distribution and Inter-CD are 4 narrowest when no catalyst deactivation occurs during the course of the polymerization which leads to termination of growing 6 chains. Presently it is known that the vanadium-based catalyst 7 catalysts used in accordance with the present invention are 8 subject to such deactivation reactions which depend to an 9 extent upon the composition of the catalyst. Although the relationship between active catalyst lifetime and catalyst 11 system composition is not known at present, for any given 12 catalyst, deactivation can be reduced by using the shortest So, 13 residence time and lowest temperature in the reactor that 14 will produce the desired monomer conversions.

15 Polymerizations in accordance with the present 0 0 0 16 invention should be conducted in such a manner and under 17 conditions sufficient to initiate propagation of essentially 18 all copolymer chains simultaneously. This can be accom- 19 plished by utilizing the process steps and conditions described below.

21 The catalyst components are preferably premixed, 22 that is, reacted to form active catalyst outside of the 23 reactor, to ensure rapid 'chain initiation. Aging of the 0 o 24 premixed catalyst system, that is, the time spent by the o 25 catalyst components vanadium compound and organo- 26 aluminum) in each other's presence outside of the reactor, o0 27 should preferably be kept within limits. If not aged for a 28 sufficient period of time, the components will not have 29 reacted with each other sufficiently to yield an adequate quantity of active catalyst species, with the result of non- 31 simultaneous chain initiation. Also, it is known that the 32 activity of the catalyst species will decrease with time so 33 that the aging must be kept below a maximum limit. It is 34 believed that the minimum aging period, depending on such factors as concentration of catalyst components, temperature.

36 and mixing equipment, could be as low as about .1 second. The V 37 preferred minimum aging period is about .5 second, while the 28 1 most preferred minimum aging period is about 1 second. While 2 the maximum aging period could be higher, for the preferred 3 vanadium/organo-aluminum catalyst system the preferred 4 maximum is about 200 seconds. 'A more preferred maximum is about 100 seconds. The most preferred maximum aging period 6 is about 50 seconds. The premixing could be performed at low 7 temperature such as 40 0 C or below. It is preferred that the 8 premixing be performed at 250C or below, with 150C or below 9 being most preferred.

The temperature of the reaction mixture should also 11 be kept within certain limits. The temperature at the reactor 12 inlet should be high enough to provide complete, rapid chain 13 initiation at the start of the polymerization reaction. The 14 length of time the reaction mixture spends at high tempera- 15 ture must be short enough to minimize the amount of un- 16 desirable chain transfer and catalyst deactivation reac- 17 tions.

S* 18 Temperature control of the reaction mixture is i 0 19 complicated somewhat by the fact that the polymerization reaction generates large quantities of heat. This problem o. 21 is, preferably, taken care of by using prechilled feed to the 0 44 1 22 reactor to absorb the heat of polymeriiation. With this 23 technique, the reactor is operated adiabatically and the 24 temperature is allowed to increase during the course of 25 polymerization. As an alternative to feed prechill, heat can 26 be removed from the reaction mixture, .for example, by a heat 27 exchanger surrounding at least a portion of the reactor or by 28 well-known autorefrigeration techniques in the caseof batch 29 reactors or multiple stirred reactors in series.

If.adiabatic reactor operation is used, the inlet 31 'temperature of the reactor feed could be about from -50 0 C to 32 500oC. It is believed that the outlet temperature of the 33 reaction mixture could be as high as about 2000C. The 34 preferred maximum outlet temperature is about 70 0 C. The most preferred maximum is about 500C. In the absence of reactor 36 cooling, such as by a cooling jacket, to remove the heat of 37 polymerization, it has been determined that the temperature i 29 1 of the reaction.mixture will increase.from reactor-inlet to 2 outlet by about 13oC per weight percent of copolymer in the 3 reaction mixture (weight of copolymer per weight of solvent).

4 Having the benefit of the above disclosure, it would be well within the skill of the art to determine the 6 operating temperature conditions for making copolymer in ac- 7 cordance with the present invention. For example, assume an 8 adiabatic reactor and an outlet temperature of 350C are 9 desired for a reaction mixture containing 5% copolymer. The reaction mixture will increase in temperature by about 13 0

C

11 for each weight percent copolymer or 5 weight percent x 12 13oC/wt.% 65 0 C. To maintain an outlet temperature of 350C, S, 13 it will thus require a feed that has been prechilled to 35 0

C-

14 65 0 C -300C. In the instance that external cooling is used i 6 15 46 15 to absorb the heat of polymerization, the feed inlet tempera- 16 ture could be higher with the other temperature constraints 17 described above otherwise being applicable.

0 00 a° 18 Because of heat removal and reactor temperature 19 limitations, the preferred maximum copolymer concentration 20 at the reactor outlet is 25 wt./l00 wt. diluent. The most f t 21 preferred maximum concentration is 15 wt/100 wt. There is no 0 22 lower limit to concentration due to reactor operability, but 23 for economic reasons it is preferred to have a copolymer 24 concentration of at least 2 wt/100 wt. Most preferred is a concentration of at least 3 wt/100 wt.

26 The rate-of flow of the reaction mixture through

S

t i t 27 the reactor should be high enough to provide good mixing of '4 28 the reactants in the radial direction and minimize mixing in 29 the axial direction. Good radial mixing is beneficial not only to both the Intra-and Inter-CD of the copolymer chains 31 but also to minimize radial temperature gradients due to the 32 heat generated by the polymerization reaction. Radial tem- 33 perature gradients will tend to broaden the molecular weight 34 distribution of the copolymer since the polymerization rate is faster in the high temperature regions resulting from poor 36 heat dissipation. The artisan will recognize that achieve- 37 ment of these objectives is difficult in the case of highly

I

30 1 viscous solutions. This problem can.be overcome to some 2 extent through the use of radial mixing devices such as static 3 mixers those produced by the Kenics Corporation).

4 It is believed that residence time of the reaction mixture in the mix-free reactor can vary over a wide range.

6 It is believed that the minimum could be as low as about 1 7 second. A preferred minimum is about 10 seconds. The most 8 preferred minimum is about 15 seconds. It is believed that 9 the maximum could be as high as about 3600 seconds. A preferred maximum is about 1800 seconds. The most preferred 11 maximum is about 900 seconds.

12 With reference to the accompanying drawings, par- S, 13 ticularly Fig 1, reference numeral 1 generally refers to a 14 premixing device for premixing the catalyst components. For 15 purposes of illustration., it is assumed that a copolymer of 16 ethylene and propylene (EPM) is to be produced using as 17 catalyst components vanadium tetrachloride and ethyl aluo0°0 18 minum sesqui chloride. The polymerization is an adiabatic, 19. solution polymerization process using hexane solvent for 20 both the catalyst system and the reaction mixture.

21 The premixing device 1 comprises a temperature 22 control bath 2, a fluid flow conduit 3 and mixing device 4 23 a mixing tee). To mixing device 4 are fed hexane 24 solvent, vanadium tetrachloride and ethyl aluminum sesqui t' 25 chloride through feed conduits 5, 6 and 7, respectively. Upon 26 being mixed in mixing device 4, the resulting catalyst 27 mixture is caused to flow within conduit 3, optionally in the 28 form of a coiled tube, for a time long enough to produce the 29 active catalyst species at the temperature set by the temperature bath. The temperature of the bath is set to give the 31 desired catalyst solution temperature in conduit 3 at the 32 outlet of the bath.

33 Upon leaving the premixing device, the catalyst 34 solution flows through conduit 8 into mixing zone 9 to provide an intimate mixing with hexane solvent and reactants (ethy- 36 lene and propylene) which are fed through conduit 10. Any 37 suitable mixing device can be used such as a mechanical ,i, 31 1 mixer, orifice mixer or mixing tee. For economic reasons, the 2 mixing tee is preferred. The residence time of the reaction 3 mixture in mixing zone 9 is kept short enough to prevent 4 significant polymer formation therein before being fed through conduit 11 to tubular reactor 12. Alternatively, 6 streams 8 and 10 can be fed directly to the inlet of reactor 7 12 if the flow rates are high enough to accomplish the desired 8 level of intimate mixing. The hexane with dissolved monomers 9 may be cooled upstream of mixing zone 9 to provide the desired feed temperature at the reactor inlet.

11 Tubular reactor 12 is shown with optional, inter- 12 mediate feed points 13-15 where additional monomers t 1.

13 ethylene as shown) and/or hexane can be fed to the reactor.

14 The optional feeds would be used in the instance where it 15 would be desirable to control the Intra-CD. While the reactor o 16 can be operated adiabatically, if desired or necessary to 17 maintain reaction mixture temperature within desired limits, o.o 18 external cooling means such as a cooling jacket surrounding 19 at least a portion of the reactor system 12 can be provided.

20 The copolymer chains formed in accordance with 21 the present invention are dispersed within the reaction 22 mixture.

23 With reference to Fig 2 which schematically illus- 24 trates a process for mixing copolymer with lube oil, copolymer product from reactor 12 is fed through conduit 16 to 26 deashing section 17 wherein catalyst residues are removed S' 27 from the reaction mixture in a known manner (known as de- 28 ashing). The vanadium and aluminum compound residues are 29 removed by reacting them with water to form hydrocaxrboninsoluble hydroxides and then extracting the hydroxides into 31 dilute acid.

32 After separating the aqueous and hydrocarbon phas- 33 es, for instance in a gravity settler, the polymer solution, 34 which primarily contains solvent, unreacted monomers and copolymer product (EPM) is fed through conduit 18 to lube oil 36 mixing tank 19. Of course, tank 19 could be a staged series 37 of tanks. Hot lube oil is fed through conduit 20 to mixing -32- 1 tank 19, wherein the remaining reaction mixture is heated urD 2 such that the remaining hexane and unreactedi monomers are 3 vaporized and removed through recycle conduit 21 through 4 which they flow back for reuse in premixing device 1 following suitable purification to remove any catalyst poisons. The 6 copolymer product, being hydrocarbon- solublIe, is now present 7 in the lube oil and is removed from tank 19 as a copolymer- 8 in-oil solution.

9 .Alternatively, the copolymer solution from the gravity settler can be steam distilled with subsequent 11 extrusion drying of the polymer and then mixed with a 12 hydrocarbon mineral oil diluent to produce an oil additive 1.3 concentrate or lube oil additive.

14 Having thus'described the above illustrative resystem, it will readily occur to the artisan that many 16 variations can be made within the scope of the present 1 invention. Foi example, the placement and number of multiple 18 feed sites, the choice of temperature profile during poly- 19 merization and the concentrations of reactants can be varied P. 20 to suit the end-use application.

21 By practicing processes in accordance with the.

22 present invention, alpha-olefin copolymers having very nar-* 0004423 row MWD can be made by direct polymerization. Although narrow P 24 MWD copolymers can be made using other known techniques, such 4 25 as by fractionation or mechanical degradation, these techni- 14126 cues are considered to be impractical to the extent of being 27unsuitable for commercial-scale operation. As regards EPDM I .1 4.

4 28 made in accordance with the present invention, the products 29 have enhanced cure properties at a given Mooney Viscosity. As regards EPM, the products hav e good shear stability and 31 excellent low temperature properties which make them es- 32 pecially suitable for lube oil applications. For lube oil 33 applications, the narrower the MWD of the polymer, the better 34 'the-copolymer is considered to be.

A lubricating oil composition in accordance with 36the present invention comprises a major amount of basestock 37lubricating oil (lube oil) of lubricating viscosity which comprised of catalyst, ethylene and at least one additional alpha-olefin monomer. Solution polymerizations are preferred.

33 I r I I 0 0 0 0 4 o 0 a 9 t t o 00 00,40 00(I I I

I

1 2 3 4 6 7 8 9 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 31 32 33 34 36 37 contains an effective amount of viscosity index improver being a copolymer of ethylene and at least one other alphaolefin as described in detail above. More specifically, the copolymer should have a MWD characterized by at least one of a ratio of Mw/Mn.of less than 2 and a ratio of Mz/Mw of less than 1.8. The preferred ratio of Mw/Mr is less than. about- 1.6, with less than about 1.4 being preferred. The preferred Mz/Mw is less than about 1.5, with less than about 1.3 being most preferred.

It is preferred that the Intra-CD of the copolymer is such that at least two portions of an individual intramolecularly heterogeneous chain, each portion comprising at least 5 weight percent of said chain, differ in composition from one another by at least 5 weight percent ethylene. The Intra-CD can be such that at least two portions of copolymer chain differ by at least 10 weight percent ethylene. Differences of at least 20 weight percent, as well as, 40 weight percent ethylene are also considered to be in accordance with the present invention.

It is also preferred that the Inter-CD of the copolymer is such that 95 wt.% of the copolymer chains have an ethylene composition that differs from the copolymer average weight percent ethylene composition by 15 wt.% or less. The preferred Inter-CD is about 13% or less, with the most preferred being about 10% or less.

In a most preferred embodiment, the copolymer has all of the MWD, Intra-CD and Inter-CD characteristics described above when incorporated in a lubricating oil or oil additive concentrate composition. In current practice, ethylene-propylene copolymer is most preferred. The preferred ethylene content of the copolymer, on a weight basis, for use as a lube oil additive is about from 0% to For lube oil additive appl'ications, it is believed that the copolymer could have a weight average molecular weight as low as about 5,000. The preferred mimimum is about 15,000, with about 50,000 being the most preferred minimum.

It is believed that the maximum weight average molecular 34 1 weight could be as high as about 500,000. The preferred 2 maximum is about 300,000, with about 250,000 being the most 3 preferred maximum.

4 Copolymers of this invention may be employed in lubricating oils as viscosity index improvers or viscosity 6 modifiers in amounts varying broadly from about 0.001 to 49 7 The proportions giving the best results will vary 8 somewhat according to the nature of the lubricating oil 9 basestock and the specific purpose for which the lubricant is to serve in a given case. When used as lubricating oils for 11 diesel or gasoline engine crankcase lubricants, the polymer 12 concentrations are within the range of about 0.1 to 15.0 wt% 13 of' the total composition which are amounts effective to 14 provide viscosity index improvements. Typically such polyi 15 meric additives are sold as oil additive concentrates wherein 16 the additive is present in amounts of about 5 to 50 wt%, I 17 preferably 6 to 25 wt% based on the total amount of hydro- 0 18 carbon mineral oil diluent for the additive. The polymers of 19 this invention are typically'used in lubricating oils based 20 on a hydrocarbon mineral oil having a viscosity of about 2- 21 40 centistokes (ASTM D-445) at 99 0 C, but lubricating oil l 22 basestocks comprised of a mixture of a hydrocarbon mineral 23 oil and up to about 25 wt% of a synthetic lubricating oil such 24 as esters of dibasic acids and complex esters derived from monobasic acids, polyglycols, dibasic acids and alcohols are 26 also considered suitable.

27 Finished lubricating oils containing the ethylenealpha-olefin polymers of the present invention will typi- 29 cally contain a number of other conventional additives in amounts required to provide their normal attendant functions 31 and these include ashless dispersants, metal or over-based 32 metal detergent additives, zinc dihydrocarbyl dithiophos- 33 phate, anti-wear additives, anti-oxidants, pour depressants, 34 rust inhibitors, fuel economy or friction reducing additives and the like.

36 The ashless dispersants include the polyalkenyl or 37 borated polyalkenyl succinimide where the alkenyl group is 35 1 derived from a C 3

-C

4 olefin, especially polyisobutenyl hav- 2 ing a number average molecular weight of about 700 to 5,000.

3 Other well known dispersants include the oil soluble polyol 4 esters of hydrocarbon substituted succinic anhydride, e.g., polyisobutenyl succinic anhydride and the oil soluble oxa- 6 zoline and lactone oxazoline dispersants derived from hydro- 7 carbon substituted succinic anhydride and di-substituted 8 amino alcohols. Lubricating oils typically contain about 9 to 5 wt.% of ashless dispernant.

The metal detergent additives suitable in the 1 oil are known in the.art and include one or more members 12 selected from the group consisting of overbased oil-soluble 13 calcium, magnesium and barium phenates, sulfurized phenates, 06 0S0 14 and sulfonates especially the sulfonates of C 1 6

-C

5 0 alkyl s, Pa 15 substituted benzene or toluene sulfonic acids which have a 16 total base number of about 80 to 300. These overbased *!Too* a 0 17 materials may be used as the sole metal detergent additive or a o 0 a o 18 in combination with the same additives in the neutral form but 19 the overall metal detergent additive combination should have o 20 a basicity as represented by the foregoing total base number.

i 21 Preferably they are present in amounts of from about 0.5 to 8 0 0 4 22 wt.% with a mixture of overbased magnesium sulfurized phenate oc,,,9 23 and neutral calcium sulfurized phenate, obtained from C to 24 C 12 alkyl phenols being especially useful.

The anti-wear additives useful are the oil-soluao 26 ble zinc dihydrocarbyldithiophosphate having a total of at @4 27 least 5 carbon atoms, preferably alkyl groups of C 4

-C

8 28 typically used in amounts of about 0.5-6% by weight.

29 Other suitable conventional viscosity index improvers, or viscosity modifiers, are the olefin polymers such 31 as other ethylene-propylene copolymers those dis- 32 closed in the prior art as discussed above), polybutene, 33 hydrogenated polymers and copolymers and 34 terpolymers of styrene with isoprene and/or butadiene, polymers of alkyl acrylates or alkyl methacrylates, copolymers of 36 alkyl methacrylates with N-vinyl pyrollidone or dimethyli with the present invention snouia u e buin a j 36 essentially one active catalyst species in the reaction 37 mixture. More specifically, it should yield one primary r.ra3- _l L 36 o 0 00 0 (0 0 000( 4 0 0 ti 0 6I 00 1 aminoalkyl methacrylate, post-grafted polymers of ethylene- 2 propylene with an active monomer such as maleic anhydride 3 which may be further reacted with alcohol or an alkylene 4 polyamine, styrene-maleic anhydride polymers post-reacted with alcohols and amines and the like. These are used as 6 required to provide the viscosity range desired in the 7 finished oil, in accordance with known formulating tech- 8 niques.

9 Examples of suitable oxidation inhibitors are hindered phenols, such as 2,6-ditertiary-butyl-paracresol, a- 11 mines, sulfurized phenols and alkyl phenothiazines; usually 12 a lubricating oil will contain about 0.01 to 3 weight percent 13 of oxidation inhibitor depending on its effectiveness.

14 Rust inhibitors are employed in very small proportions such as about 0.1 to 1 weight percent with suitable 16 rust inhibitors being exemplified by C 9

-C

30 aliphatic suc- 17 cinic acids or anhydrides such as dodecenyl succinic anhy- 18 dride.

19 Antifoam agents are typically the polysiloxane 20 silicone polymers present in amounts of about 0.01 to 1 weight 21 percent.

22 Pour point depressants are used generally in a- 23 mounts of from about 0.01 to about 10.0 more typically 24 from about 0.01 to about 1' for most mineral oil 25 basestocks of lubricating viscosity. Illustrative of pour 26 point depressants which are normally used in lubricating oil 27 compositions are polymers and copolymers of n-alkyl meth- 28 acrylate and n-alkyl acrylates, copolymers of di-n-alkyl 29 fumarate and vinyl acetate, alpha-olefin copolymers, alkylated naphthalenes, copolymers or terpolymers of alpha- 31 olefins and styrene and/or alkyl styrene, styrene dialkyl 32 maleic:copolymers and the like.

33 As noted above, copolymer products made in 34 accordance with the present invention have excellent low temperature properties which makes them suitable for lube 36 oil applications. Accordingly, lube oil compositions made C) ti.Y 4 0.n 0 0 0000 00 0 o greater than 10. These other catalysts are deemed to have 36 more than one active species.

37 Catalyst systems to be used in carrying out pro- 37 1 in accordance with the present invention preferably have 2 a Mini Rotary Viscosity (MRV) measurement in centipoises 3 (cps) at -250C according to ASTM-D 3829 of less than 4 30,000. A more preferred MRV is less than 20,000, with less than 10,000 being most prefe- I.

6 With reference again v. processes for making co- 7 polymer in accordance with the present invention, it is 8 well known that certain combinations of vanadium and 9 aluminum compounds that can comprise the catalyst system can cause branching and gelation during the polymerization 11 for polymers containing high levels of diene. To prevent 12 this from happening Lewis bases such as ammonia, tetra- 13 hydrofuran, pyridine, tributylamine, tetrahydrothiophene, 14 etc., can be added to the polymerization system using techniques well known to those skilled in the art.

Stt 16 Example 1 17 In this example, an ethylene-propylene copolymer 18 was prepared in a conventional continuous flow stirred tank 19 reactor. Catalyst, monomers and solvent were fed to a 3 gallon 20 reactor at rates shown in the accompanying Table I. Hexane was 21 purified prior to use by passing over 4A molecular sieves 22 (Union Carbide, Linde Div. 4A 1/16" pellets) and silica gel 23 R. Grace Co., Davison Chemical Div., PA-400 20-40 mesh) to 24 remove polar impurities which act as catalyst poisons. Gaseous ethylene and propylene were passed over hot (270 0 C) CuO 26 (Harshaw Chemical Co., CU1900 1/4" spheres) to remove oxygen 27 followed by mol sieve treatment for water removal and then were 28 combined with the hexane upstream of the reactor and passed 29 through a chiller which provided a low enough temperature to completely dissolve the monomers in the hexane. Polymeriza- 31 tion temperature was controlled by allowing the cold feed to 32 absorb the heat of reaction generated by the polymerization.

33 The reactor outlet pressure was controlled at 413 kPa to ensure 34 dissolution of the monomers and a liquid filled reactor.

Catalyst solution was prepared by dissolving 37.4 g 36 of VC1 4 in 7 1 of purified n-hexane. Cocatalyst consisted of 37 96.0 g Al 2 Et 3 Cl 3 in 7 1 of n-hexane. These solutions were fed hydrocarbon-soluble complexes with VC1 3 such as tetrahydro- 36 furan, 2-methyl-tetrahydrofuran and dimethyl pyridine.

37 38 1 to the reactor at rates shown in Table I. For the case of 2 catalyst premixing the two solutions were premixed at 0 0 C for 3 10 seconds prior to entry into the reactor.

4 Copolymer was deashed by contacting with aqueous base and recovered by steam distillation of the diluent with 6 mill drying of the product to remove residual volatiles. The 7 product so prepared was analyzed for composition, composi- 8 tional distribution and molecular weight distribution using 9 the techniques discussed in the specification. Results were as in Table I.

11 The copolymers were essentially compositionally ho- 12 mogeneous with heterogeneity about the averaae, i.e.

13 within experimental error.

14 These results indicate that for copolymer made in a 15 continuous flow stirred reactor the Mw/Mn was about 2 and the oooo o o 16 Intra-CD was less than 5% ethylene. Catalyst premixing had no o 17 effect-on Mw/Mn-or compositional distribution. Experiments 18 over a range of polymerization conditions with the same 19 catalyst system produced polymers of similar structure.

I €I S It t4 4 t 4 r mixture the Mw/Mn of the copolymer may rise above 36 on these considerations, the maximum Al/V could be 37 however, a maximum of about 17 is more preferred.

2. Based about. The most 39 TABLE I o pp o 0 0 0 0 0 0 0 0 0 0 0 0 OW Reactor Inlet Temperature (OC) Reactor Temperature (OC) Reactor Feed Rates Hexane (kg/hr) Ethene (g/hr) Propene (g/hr) VCl 4 (g/hr) .0 Al Et 3 Cl (g/hr) 0 Catalyst Premixing Temperature Catalyst premixing Time (sec) 0 Reactor Residence Time (min) Rate of Polymerisation (g/hr) Catalyst Efficiency (g polymer/g V) (1rw) 1 (Mw/Mn) b o Average Composition (Ethylene Compositional Distribution(d) In Original Fragmented max min max min Example 1A 48 42 48 45 Example 1A -40 38 39.0 1037 1404 5.41 17.4 Not premixed Not premixed 10.5 2256 416 1.5X10 5 2.1 1.7 43 Example 1B 37.5 23.7 775 1185 2.56 13.2 0 17.1 1516 591 2.1x10 s 1.9 1.7 47 p p 000 0 0f til ter- CD In t La-CD High Low Ethylene Ethylene 0 0 p* 0 0 0 U 4 Example IB 48 42 50 46 Determined by GPC/LALLS using total scattered light intensity in 1,2,4 trichlorobenzene at 135 0 Chromatix KMX-6, specific refractive index increment dn/dc=-.104 g/cc." 1 (see specification) Determined from an elution time-molecular weight relationship as discussed in the specification, data precision Determined by ASTM D-3900 Method A. Data good to t 2 ethene.

weight of copolymer product, that Al/V should be used which 36 gives the highest molecular weight also at acceptable cata- 37 lyst activity. Chain transfer with propylene can best be 39a Composition determined on fractions which comprise 5-20% of the original polymer weight, hexane-isopropyl alcohol is solvent-non solvent pair.

Inter-CD is determined as the difference between the maximum and minimum of the original polymer and the average composition.

Chains fragmented to ca. 5% of their original molecula r veight. Intra-CD is determined as the difference in composition between the highest ethylene fractions of the original and fragmented chains and between the lowest such fractions.

te 4 6 6~ 4 4 *~1

I

I

r It t f

II

(4 4 441 40 1 Example 2 2 This example is seen to illustrate the importance 3 of reaction conditions in practicing methods in accordance 4 with the invention such as catalyst premixing for making narrow MWD polymer with the desired Intra-CD. In examples 6 and the catalyst components were premixed in 7 order to obtain rapid chain initiation. In example the 8 polymerization conditions were similar, but the catalyst 9 components were fed separately to the reactor inlet.

The polymerization reactor was a one-inch diameter S, 11 pipe equipped with Kenics static mixer elements along its 12 length. Monomers, hexane, catalyst, and cocatalyst were con- 13 tinuously fed to the reactor at one end and the copolymer 14 solution and unreacted monomers were withdrawn from the other 15 end. Monomers were purified and reactor temperature and 16 pressure was controlled as in Example 1.

0 0o 17 A catalyst solution was prepared by dissolving 18.5 18 g of vanadium tetrachloride, VC1 4 in 5.0 1 of purified n-hex- 19 ane. The cocatalyst consisted of 142 g of ethyl aluminum 20 sesqui chloride, Al 2 Et 3 Cl 3 in 5.0 1 of purified n-hexane. In 21 the case of catalyst premixing, the two solutions were pre- 22 mixed at a given temperature (as indicated in TABLE II) for 23 10 seconds prior to entry into the reactor.

24 Table II lists the feed rates for the monomers, catalyst, and the residence time of examples and S26 Polymer was recovered and analyzed as in Example 1.

27 Figure 5 illustrates the polymer concentration- 28 residence time relationship, with concentration being 29 presented in terms of polymer concentration at residence time t (CAt residence time't )/polymer concentration at final t 31 (CFinal t) which exists at the end of th reactor. It is 32 evident that in example 2(B. the maximum polymerization rate 33 occurs at about zero reaction time indicating fast initiation 34 of all the polymer chains. As a result, a very narrow MWD EPM with (Mw/Mn) equal to 1.3 and (Mz/Mw) of 1.2 was produced 36 through a process in accordance with the present invention.

i: 41 1 On the other hand, example shows that EPM with 2 Mw/Mn greater than 2.0 and Mz/Mw of 2.0 was obtained when the 3 proper conditions were not used. In this example, lack of 4 premixing of the catalyst components led to a reduced rate of chain initiation and broadened MWD.

6 Samples of product were fractionated according to 7 the procedure of Example 1 and as diselosed in the specifica- 8 tion. Data appear in Table II.

9 Sample A, made without catalyst premixing, had a broad Inter-CD typical of the prior art Junghanns).

11 For samples B and C Inter-CD was much reduced as a result of 12 the premixing.

13 Intra-CD is shown as the difference between the 14 fractionation data on the fragmented and unfragmented sama 15 ples. For sample B, the chains are shown to contain segments o 16 of at least 6% ethylene higher than that isolatable on the 0" 17 unfragmented material. The residual Inter-CD obscures the 18 analysis of Intra-CD. To make the analysis clearer, sample o 19 C was first fractionated and then one fraction (the 3rd) was 20 refractionated showing it to be homogeneous with regard to 21 Inter-CD. Upon fragmentation a compositional dispersity as 22 large as the original whole polymer Inter-CD was obtained.

23 Thus, those chains must have had an Intra-CD of greater than a a 24 18%. The 2nd and 3rd fractions, which were similar, comprised o. 25 more than 70% of the original polymer showing that the Inter- 26 CD which obscured the Intra-CD was only due to a minor portion 27 of the whole polymer.

28 Since the fractionation procedure might depend on 29 the solvent non-solvent pair used, a second combination, carbon tetrachloride-ethyl acetate was used on the sample C 31 whole polymer. This pair was also used in the prior art. It 32 is apparent from the data of Table II that hexane-isopropanol 33 separated the polymer more efficiently than CCl 4 -ethyl ace- 34 tate.

A

42 TABLE II Example 2A Reactor Inlet Temperature (1C) -20 Reactor Inlet Temperature (1C) -3 Reactor Feed Rates Hexane (kg/hr) 60.3 Ethene (kg/hr) 0.4 Propene (kg/hr) 3.2 VCl 4 (g/hr) 2.22 2 Et 3 Cl 3 (g/hr) 20.5 Catalyst Premixing Temperature (OC) S Catalyst Premixing Time (sec) 0 'a Reactor Residence Time (sec) 52 Rate of Polymerisation (g/hr) 874 Catalyst Efficiency (g polymer/g VCl 4 394 (fMw) 2. 1x10 2.0 '20 (FMw/Mn)(b) 2.70 Composition (ethene 42.4 1 Compositional Distribution (d) Example 2B Example 2C -10 0 0 60.3 0.22 2.0 2.22 17.0 60.3 0.22 2.22 17. 0 426 227 1. 4xl0 5 1.2 1.3 39.1 9 5xl0 4 1.2 1.2 41.4 V 25 original Fragmented max min max min 25 Intra C g Inter CDf max min +13 (e) 32 51 32 +6 -7 49 34 51 (39) +8 +6 0 +2 (e) 2C 3rd cut ref ractionated 2C CC 4 -ethyl ace tate 42 39 48 32 45 34 an intimate mixing with hexane solvent and reactants (ethy- 36 lene and propylene) which are fed through conduit 10. Any 37 suitable mixing device can be used such as a mechanical 42a Determined by GPC/LALLS using total scattered light intensity in 1,2,4, trichlorobenzene at 135 0 C, Chromatix KMX-6, specific refractive index increment dn/dc=-.104 g/cc.- 1 (see specification) Determined from an elution time-molecular weight relationship as discussed in the specification, data precision Determined by ASTM D-3900 Method A. Data good to ethene.

Composition determined on fractions which comprise 5-20% of the original polymer weight, hexane isopropyl alcohol is solvent-non solvent pair.

S(e) In these cases inter DC obscured intra CD so no increase in CD was shown on fragmentation.

Inter-CD is determined as the difference between the maximum and minimum of the original polymer and the average composition.

O 0 Chains fragmented to ca. 5% of their original molecular weight. Inter-CD is determined as the difference in composition betweem the highest ethylene fractions of the original and fragmented chains and between the lowest such So fractions.

o 00 0 0 o 0 0 copolymer product (EPM) is fed through conduit 18 to lube oil 36 mixing tank 19. Of course, tank 19 could be a staged series 37 of tanks. Hot lube oiL is fed through conduit 20 to mixing 43 1 Example 3 2 This example illustrates the use of additional mon- 3 omer feed downstream of the reactor inlet (multiple feed 4 points) to vary polymer composition and compositional distribution while maintaining a narrow MWD. In example a 6 second hexane stream containing only ethylene was fed into the 7 reactor downstream of the inlet in addition to those feeds used 8 at the inlet. In example the polymerization conditions 9 were the same except there was no second ethylene feed. The polymerization procedures of example were repeated. The 11 process conditions are listed in Table III.

0 12 The data listed in Table III show that the sample 13 made with an additional monomer feed downstream of the reactor S 14 inlet had the same MWD as the one made with all the monomer feed at the reactor inlet. This combined with the increases in o'o 16 ethylene composition of the "2nd feed point" sample and the o° o 17 molecular weight of the final sample in example indicate 18 that the monomers in the second feed had been added to the 19 growing polymer chains. Therefore, the Intra-CD of the final product must be as shown schematically in Figure 6.

oo* 21 It is apparent that since the chains continue to grow 22 down the tube that a variety of structures can be produced by 0 23 using multiple feed points as noted in the specification.

U r 0 SCI0O 0 4 44 1 Table III 2 Example 3B Example 3A 3 Solvent Temperature (oC) 4 Main Feed -10 Second Feed 0 G Reactor Outlet Temperature (OC) +3 0 7 Reactor Feed Rates 8 Bexane (kg/hr) 9 Main Feed 60.7 60.7 Second Feed 9.9 11ii Ethylene (kg/hr) 12 Main Feed 0.22 0.22 13 Second Feed 0.10 14 Propylene (kg/hr) 2.0 VC14 (g/hr) 2.22 2.22 16 Al 2 Et 3 CI~ (g/hr) 17.0 17.0 17 Reactor Residence Time (see).

18 Before the 2nd feed point 4 19 Overall 35 Premixing Temperature (OC) 0 0 21 ?remixing Tie (sec) 6 6 22 Rate of Polymerization (g/hr) 487 401 23 Catalyst Efficiency (g polymer/g VC14 219 181 24 1.3 x 105 1.0 x 105 (zlw) 1.2 1.3 26 1.25 1.24 27 Composition (ethylene vt.%) 27 Reactor sample taken right after 29 the 2nd feed point 55.3 47.6 Final sample 45.4 41.0 4 ij -U Ithat tne copolymer could have a wegrint averag5 moieuujL Sweight as low as about 5,000. The preferred mimimum is about 36 15,000, with about 50,000 being the most preferred minimum.

It is believed that the maximum weight average molecular i 45 1 Example 4 2 The comparison in this example illustrates that 3 narrow MWD EPM can also be produced in a tubular reactor 4 using the vanadium oxytrichloride (VOC1 3 )-ethyl aluminum sesqui chloride (Al2Et 3 Cl 3 system when the conditions 6 described, earlier are used. In example the catalyst 7 components were premixed in order to obtain rapid chain ini- 8 tiation. In example the polymerization conditions o 9 were the same, but the catalyst components were fed 10 separately to the reactor inlet. The polymerization pro- 11 1 1 cedures of example and 2(B. were repeated. -Table IV 12 lists the run conditions.

13 The data in Table IV indicate that premixing of the 14 catalyst components produces narrow MWD polymers (Mw/Mn 1.8 and t s St 'C 4 4 0 t s OB o o a a 8 4@GIIC o C 464 4 4 and the like.

36 The ashless dispersants include the polyalkenyl or 37 borated polyalkenyl succinirnide where the alkenyl group is 46 Table IV Exa: Reactor Inlet Temperature (00 Reactor Outlet Temperature (OC) Reactor Feed Rates Eexane (kg/hr) Ethylene (kg/hr) Propylene (kg/hr) VOC13 (g/hr) A12Et3cl3 (g1hr) P remixing Temperature (00 Premixir.Lg Time (seic) Reactor Residence Time (see) Rate of Polymerization (g/br) C8talYs t Ef ficiencY (9 P017mer/9 V OC13) 2.6

Z-Z

Cffw/Fln) Composition (ethylene wt.%) ple, 4A 0 7 60.2 0.2 3.6 1.73 7.

52 685 208 X 10 2.7 2.7 40 Example 4B 0 12 61.1 0.4 2.6 5.07 54.2 6 37 359 135 3. *3 x 105 1.8 4-9 at 9 4 4 34 terpolymers of styrene with isoprene and/or butadiene, polymers of alkyl acrylates or alkyl methacrylates, copolymers of 36 alkyl methacrylates with N-vinyl pyrollidone or dimethyl- 47 1 Example 2 3 This example illustrates that narrow MWD ethylene- 4 propylene-diene copolymers (EPDM) can be produced in a tubular reactor. with premixing of the catalyst components. The 6 polymerization procedures of example were repeated, 7 except that a third monomer, 5-ethylidene-2-norbornene (ENB) 8 was also used. The feed rates to the reactor, premixing 9 conditions, and the residence time for example and oo 10 are listed in Table V. Also shown in Table V are the results 11 of a control polymerization (5C) made in a continuous flow 12 stirred tank reactor.

13 The copolymer produced was recovered and analyzed by 14 the procedures described in Example 1 above. In addition, the ENB content was determined by refractive index measurement S 16 J. Gardner and G. Ver Strate, Rubber Chem. Tech. 46, 1019 6 o a "17 (1973)). The molecular weight distribution, rate of polyo 18 merization and compositions are shown in Table V.

S19 The data listed in Table V clearly demonstrate that S' 20 processes in accordance with the present invention also result 21 in very narrow MWD for EPDM.

22, Sample and a polymer made in a continuous S' 23 flow stirred reactor with similar composition and molecular 24 weight, were compounded in the following formulation: 26 Polymer 100 27 High Abrasion Furnace 28 Black (PHR) 29 Oil (PHR) Z'nO (PHR) 2 31 Tetramethylthiuram Di- 1 32 sulfide (PHR) 33 2-Mercaptobenzothiazole 34 (PHR) S (PHR) As noted above, copolymer products made in 34 accordance with the present invention have excellent low temperature properties which makes them suitable for lube 36 oil applications. Accordingly, lube oil compositions made ff 48 1 The cured properties of these compounds are shown below: 2 5B Control 3 Cure. 160°C/10' 4 Tensile 1334 1276 Elong. 570 550 6 100% Mod. 244 261 7 200% Mod. 412 435 8 300% Mod. 600 618 9 400% Mod. 840 841 10 500% Mod. 1160 1102 11 Shore A 78 00 0 o 12 Monsanto: 160oC/60', 1° arc, 0-50 Range(a) o 13 (in-lb/dNa) o 14 L 2.8/3.2 4.0/4.5 H 37.2/42.0 35.0/39.6 16 ts2( d 2.8 17 t, 90 e) 22.2 18.5 18 Razte 7.9/8.9 5.9/6.7 0 O0 19 Monsanto Rheometer, Monsanto Company (Akron, OH) 0 0 20 ML Cure meter minimum torque; ASTM D2084-81 21 MH Cure meter maximum torque; ASTM D2084-81 oa 9 t) S22 ts2 Time (in minutes) to 2-point rise above minimum 23 torque; ASTM D2084-81 24 t'90 Time (in minutes) to reach 90% -of-maximum torque rise above minimum; ASTM D2084-81.

26 These data show that the cure rate of the narrow 27 MWD polymer was greater than that for the continuous flow 28 stirred reactor control polymer even though 29 and ENB content were lower for the former. Thus, the benefit of narrow MWD on cure rate is shown.

Catalyst solution was prepared by dissolving 37.4 g Of VC1 4 in 7 1. of purifiJed n-hexane. Cocatalyst consisted of 96.0 g A1 2 Et 3 Cl 3 in 7 1 of n-hexane. These iouin wee.e -7 49 Table V I I t Exanple 5A Reactor Tubul-ar Reactor Inlet Temperature (00 0 Reactor Outlet Temperature (00 20 Reactor Feed Rates Bexane (kg/hr) 60.9 Ethylene (kg/hr) 0.65 Propylene Ocg/hr) 5.5 Diene (kg/hr) 0.036 VC14 5.24 A12Et3CI3 (glhr) 40.4 Catalyst 7remi-xin., Temperature (00 0 Catalyst Premixing Time (see) 6 Reactor Residence Time (see) 30 Late of Polymerization 1479 Catalyst Efficinecy (z polymer/& V C14) 282 1.3 x 105 (ffz/HW) 1.37 Gw/gn) 1.

Kooney Viscosity MI 1000C 45 Composition Ethylenewt,.% 39.3 EhB U-t. x 3.5 'Cure Rate (dNm) Ex=ple 5B Tubular 60.9 0.20 2.15 0.026 2.22 21.4 48 454 205 1. 2 x 105 1.30 1.61 51 9. 3 4.2 8.9 Ex=ple S-Hrred, Tank 1.6 4.

4.

49.

6.7 Example 6 This example illustrates that narrow MWD EPM can be produced in a tubular reactor with a different configuration when the critical process conditions in accordance with the present invention are used. The polymerisation reactor consisted of 12 meters of a 3/8" tubing. The experimental procedures of example were repeated. The process conditions are listed in Table VI.

Data listed in Table VI show that this tubular reactor produced polymer with an MWD as narrow as that of polymers made in the 1" pipe used in the previous example.

TABLE VI Reactor Inlet Temperature -1 Reactor Outlet Temperature (OC) Reactor Feed Rates S Hexane (kg/hr) 31.1 Ethylene (kg/hr) 0.7 Propylene (kg/hr) 11 VC1, (g/hr) 8.27 Al Et 3 C1, (g/hr) 58.5 Reactor Residence time (sec) Catalyst Premixing Temperature (OC) Catalyst Premixing Time (sec) 6 Rate of Polymerisation (g/hr) 1832 Catalyst Efficiency (g polymer/g VCl 1 222 (rw) 1.4x10 (MI /rMw) 1.4 (Mw/n) Composition (ethylene 38 Surtify that this and tho preo ding true ard exat copy of p4ges q v, p a g es a r e f, the P6eiticoation original g l odgdd,o of f c^ng discussed in the specification, data precision L-.

1 Determined by ASTM D-3900 Method A. Data good to L 2 ethene.

51 1 Examples 7-10 2 In these examples, polymers made as described in the previous 3 examples were dissolved in lubricating oil basestock and the 4 viscosity effects were evaluated. The narrow MWD and intramolecular compositional distribution of these polymers provide S, 6 improvements in MRV (Mini Rotary Viscosity) 'and SSI (Sonic S 7 Shear Index).

S° 8 MRV: This is a viscosity measurement in centipoises'(cps) at 9 -25 0 C according to ASTM-D 3829 using the Mini-Rotary Viscometer and is an industry accepted evaluation for the low temperature 11 pumpability of a lubricating oil.

e* 12 This represents Thickening Efficiency and is defined as 13 the ratio of the weight percent of a polyisobutylene (sold as 14 an oil solution by Exxon Chemical Company as ParatoneN), having a Staudinger molecular weight of 20,000, required to thicken a 16 solvent-extracted neutral mineral lubricating oil, having a 17 viscosity of 150 SUS at 37.8 0 a viscosity index of 105 and 18 an ASTM pour point of (Solvent 150 Neutral) to aviscosity 19 of 12.3 centistokes at 98.9 0 to the weight percent of a test copolymer required to thicken the same oil to the same viscosity 21 at the same temperature.

22 SSI: This value is Shear Stability Index and measures the 23 stability of polymers used as V.I. improvers in motor oils 24 subjected to high shear rates. In this method the sample under test is blended-with a typical basestock to a viscosity increase 26 at 210 0 F of 7.0 +5 centistokes. Two portions of the blend are 27 successively subjected to sonic shearing forces at a specific 52 1 power input and a constant temperature for 15 minutes.

2 Viscosities are determined on the blends both before and 3 after the treatment; the decrease in viscosity after the 4 treatment is a measure of the molecular breakdown of the polymer under test. A series of standard samples is used 6 as a reference to establish the correct value for the sam- 7 ple under test. The corrected value is reported .s the 8 SSI which is the percent sonic breakdown to the nearest 9 1%.

S" 10 In these tests, a Raytheon Model DF 101, 200 11 watt, 10 kilocycle sonic oscillator was used, the temper- 12 ature was 37 +4 0 C, power inputis 0.75 ampere, time of 13 test is 15.0 minutes +10 seconds.

14 Example 7 In this example, polymers made as described in Examples 16 1 and 2 were dissolved in lubricating oil to provide a 17 kinematic viscosity of 13.5 centistokes at 100 0 C (ASTM 18 D445) SSI was measured in Solvent 150 Neutral basestock 19 (31 cs. min at 100 0 F, pour point of 50 0 F and broad wax 4 1 S; 20 distribution). MRV was measured in a Mid-Continent base- 21 stock being a mixture of Solvent 100 Neutral (20 cS. min 22 at 100°F) and Solvent 250 Neutral (55 cS. min at 100 0

F)

23 and having a narrow (C 24

-C

36 wax distribution and contain- 24 ing 0.2 wt% vinyl acetate fumarate pour depressant (Paraflow 449, Exxon Chemical Co.).

26 Results are tabulated below: 27 Shear Stability Pumpability 28 Oil Containing 29 Cbpolyner as Ethylene Thickening SSI Described In: wt% Efficiency Loss MRV -250C cps 31 Exanple 1 42 2.8 28 32,500 32 Example 2A 42 3.6 44 270,000 33 Example 2B 39 2.7 18 25,000.

34 Example 2C 41 2.06 8 20,000 ev Iut.-1 L. L.4 A.occurs at about zero reaction time indicating fast initiation of all the polymer chains. As a result, a very narrow MWD EPM with (Mw/Mn) equal to 1.3 and (Mz/Mw) of 1.2 was produced through a process in accordance with the present invention.

53 These data clearly show the improvements in SSI and MRV possible with the polymers of the present invention.

Example 2B outperformed Example 1 in SSI at the same TE.

Both Examples 2B and 2C, made with premixed catalyst, outperformed Example 1 (made as in Ex. 1) from the backmixed reactor, and Example 2A, made with no premixing and having the broad inter CD.

Example 8 In this example it is shown that the polymer of Example 3, which was made with multiple ethylene feeds and which retained its narrow MWD even with a second ethylene feed, has good shear stability.

94 1 999, 909999 0 9 99 99 09 4 4 4 9944 9 9' .9 9 91 4 9 4*9 49 99 9 4 99 .04990 9 994991

I

tq~ 499191 9 9 Sample Example 2B Example 3B

TE

2.7 2.6 SSI Loss 18 14.5 The shear stability of 3B was equivalent to the polymer made with the single feed. Thus, it is possible to tailor compositional distribution without significantly affecting MWD and SSI.

Example 9 In this example it is shown that the premixing of the VOCI 3 catalyst components of Example 4, which effected a narrowing of MWD, permits a much higher TE polymer to be employed with the same SSI, as shown in Table 9.

Table 9 Sample Example 4A Example 4B

TE

3.8 4.9 SSI Loss 52 53 separated the polymer more efficiently than CCl 4 -ethyl acetate.

I;

fr 54 It should be noted, however, that a polymer of the same TE as the polymer of Example 4A, when made with premixing exhibits much better SSI than the Example 4A.

Example This example demonstrates a terpolymer in accordance with this invention exhibits the same viscosity improvements. A terpolymer sample was prepared as in Example This sJnple was tested for SSI and MRV. Sample analysis and results appear in Table Table 44 0 4 4 Sample Ethylene wt% Exanple 10A 39.3 ENB wt% 3.5 TE MR1_ 2.5 33,000 SSI, loss 29 o4 4 0 a 0 00 t I t t ll C

Claims (19)

1. In a polymerization process for producing copolymer in the form of copolymer chains, from a reaction mixture comprised of catalyst, ethylene, and at least one other alpha-olefin monomer, the improvement which comprises conducting the polymerization: in at least one mix-free reactor/, aS with essentially one active catalyst species, using at least one reaction mixture which is a oo essentially transfer agent free, and in such a manner and under conditions sufficient to initiate propagation of essentially all copolymer chains simultaneously, wherein the copolymer chains produced are dispersed with the reaction mixture. St

2. A process according to Claim 1, wherein the catalyst comprises hydrocarbon-soluble vanadium compound and organo-aluminum compound which react to form essentially one active catalyst species, at least one of the vanadium compound and organo-aluminum compound containing a valence-bonded halogen.

3. A process according to Claim 1 or 2, wherein the inlet temperature of the reaction mixture is about- -50 0 C to 150 0 C.

4. A process according to Claim 3, wherein the maximum outlet temperature of the reaction mixture is a~1gw. 200 0 C. A process according to Claim 4, wherein the catalyst components are premixed, and wherein the polymerization is a solution polymerization. -i i ,i i c- «ro~-c -56- crn i x r e c

6. A process according to Claim 5, wherein the) catalyst components are aged for at least about .5 seconds.

7. A process according to Claim 2, wherein the mole ratio of aluminum to vanadium in the catalyst is about 2 to

8. A process according to Claim 5, wherein the r reaction mixture leaving the reactor has a copolymer concentration of ab-ut 3 to 15% on a weight of copolymer per weight of solvent basis.

9. A process according to Claim 1, wherein the catalyst comprises a Ziegler catalyst. A process according to Claim 3, wherein the maximum 4 outlet temperature of the reaction mixture is abeti 50 0 C. N 4

11. A process according to Claim 8, wherein the catalyst comprises components that are premixed and then 4 aged for eabut 1 to 50 seconds. 0* 4t 1

12. A process according to Claim 8, wherein the mole ratio of aluminum to vanadium in the catalyst is about 4 to

13. A process according to Claim 12, wherein the polymerization is conducted in a solvent for the reaction mixture, and wherein the reaction mixture leaving the reactor has a copolymer concentration of abou4- 3% to 10% on a weight of polymer per weight of solvent basis.

14. A process according to Claim 2, wherein the catalyst comprises: i r -r L U r 4 -57- hydrocarbon-soluble vanadium compound selected from the group consisting of: 0 4X(OR 3 where x=0-3 and R=hydrocarbon radical: VCl 4 VO(AcAc) 2 where AcAc=acetyl acetonate V(AcAc 3 where AcAc=acetyl acetonate V0Cl, (AcAc) 3 -x where x=l or 2 and AcAc=acetyl acetonate; and VCl 3 nB, where n=2-3 and B=Lewis base capable of forming hydrocarbon-soluble complexes with VCl 3 and 43 o 4(b) organo-aluminum compound selected from the group consisting of: 0 4AlR 3 AlR 2 Cl Al 2 R 3 C1 3 AlRCl 2 Aa.IR R, Al(OR' )R 2 R 2 A-OAlR 2 F and AlR~ 21 where R arid R' are hydrocarbon radicals. -58- A process according to Claim 2, wherein the catalyst comprises VC1 4 and Al 2 R Cl

16.. A process according to Claim 4, wherein the maximum outlet temperature of the reaction mixture is ab-~ut 70 0 C.

17. A process according to Claim 16, wherein the polymerization is adiabatic.

18. A process according to Claim 17, wherein the Scatalyst comprises one active species which provides for at least 65% of the total copolymer produced.

19. A process according to Claim 18, which is continuous and is conducted in hexane solvent. V 20. A process according to Claim 1, wherein said copolymer product is cured. A process according to Claim 1, wherein said polymerization is conducted in at least one tubular reactor.

22. A process according to Claim 21, wherein said reaction mixture further comprises diene, and wherein at least one of said ethylene, other alpha-olefin monomer and diene are fed to said tubular reactor at multiple feed sites.

23. A process according to Claim 1, wherein said copolymer product is blended with basestock lubricating oil.

24. A process according to Claim 23, wherein said copolymer product is blended with the basestock lub-icating oil in an amount of from abou-t .001 to 49 wt.%. -59- A process according to Claim 1, wherein said copolymer is blended with hydrocarbon mineral oil diluent in an amount of from-aeut t5 to 50 wt.%. DATED this 9th day of November, 1987. a 4r 09 9 U0 1 EXXON RESEARCH AND ENGINEERING COMPANY EDWD. WATERS SONS, Patent Attorneys, 50 Queen Street, MELBOURNE. Vic. 3000. AUSTRALIA. 4. 6: AML) 0 0 0 0.0 0