CA1111019A

CA1111019A - Ethylene polymers and oil compositions containing same

Info

Publication number: CA1111019A
Application number: CA300,212A
Authority: CA
Inventors: Robert L. Elliott; Lawrence J. Engel; J. Brooke Gardiner
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1977-04-13
Filing date: 1978-03-31
Publication date: 1981-10-20
Also published as: AU3487078A; JPS53127588A; FR2387263A1; FR2387263B1; AU522414B2; DE2815427C2; DE2815427A1; JPS62959B2

Abstract

ABSTRACT OF THE DISCLOSURE

An ethylene polymer, preferably an oxidatively and mechanically degraded ethylene polymer comprising 26-79 weight percent (35-85 mole percent) ethylene, a C3 to C18 higher alpha-olefin and from about 1-25 weight percent of an alkyl norbornene having from about 8 to 28 carbons atoms, preferably ethyl norbornene, which is suitable as a viscosity index improver for lubricating oils.
The polymer may be used in a lubricating oil composition comprising a major amount of lubricating oil and a viscosity index-improving amount of said oil-soluble polymer and preferably at least a pour point depressing amount of a lubricating oil pour point depressant, e.g. an alkyl fumarate/vinyl acetate copolymer, whereby superior low temperature viscometrics is provided to said lubricating oil composition.

Description

1 This invention relates to novel lu4ricant additives

2 and the preparation thereof. More-particularly, it relates

3 to improvement in tl.e viscosity index of lubricating oils by

4 addition thereto of a certain class of ethyle~e copolymers S which provide said lubricating oil with excell~nt low temper-6 ature viscometric properties.
7 Recently, ethylene-propylene copolymers have be-8 come widely used as viscosity improvers in lubricating oils q because o$ the low treat levels and improved vi~cometric lo properties. However, the market requires different molecu-11 lar weight grades, which have different degrees of thicken-2 ing effect, usually called Thickening Efficiency, so as to be 3 operable with different viscosity mineral oils. Although 14 the preparation of each of such copolymer grades can be by direct synt~esis, the different molecular weight grades can 16 be produced by !aegrada~on oan ethylene-propylene copolymer 17 so as to produce lower molecular weight versions. It is ad~
8 vantageous to use the degradation approach since it is more economical to make a large run of copolymer in a large-scale ~ polymer plant, and then to use this run as a base material 21 which is then broken down into lower molecular weight grades 22 in order to~ meet requirements o. the viscosity index-improver ?3 market. There are variou$ means to achieve such degradation 24 including: heating an amorphous rubbery ethylene-propyLene copol~mer or 3 to 30 minutes at fram 260 to 420C. with the 26 exclusion of air (see United Kingdom Patent 1,001,455); ex-27 truding and heating an ethylene copolymer ~irst at 150-280C.
28 until molten and then at a temper~ture of 300-500C. with the 29 exclusion`of air (see Canadian Patent 991,792); and by oxi-dative and mechanical degradation, as by mastication, of -~ r~

.
l ethylene-propylene copolymers pre~erably frée of other mono-2 mers such as dienes (see U.S. Patent 3,769,216~ It is known 3 that ethylene terpolymers which contain dienes, e.g. vinyl 4 norbornene, are not suitable for mechanical degradation as

5 by mastication in the presence of air or oxygen whereby oxi-

6 dation occurs since this degrada~ion technique produces ex-

7 cessive amounts of gel particles which are oil insoluble.

8 Frequently, it is also found that the presence o~

9 ethylene copolymeric V.I. improvers in conventionally-formu-lated lubr~cating oils undesirably raise the low temperature Il pour point of a lubricating oil containing a pour point de-l2 pressant. This appears to occur because these copolymeric 13 V.I. improvers interfere with the operation of the lubri-.
4 cating oil pour point depressants. Representative of theselS copolymeric V.I. improvers that are frequently incompatible 16 with pour depressants are ethylene-propylene copolymers con-17 taining 60-80 mole percent of ethylene (see U.S. Patent 18 3,697,429).
l9 One approach to overcoming this incompatibility problem is taught in U.S Patent 3,6973429 wherein the V.I.
21 improver is a mixture of two ethylene copolymers, i.e. a 22 first copolymer of ethylqne and a C3 to C18 higher alpha-23 olefin having an ethylene content of 50-95 mole percent (40 24 83 wt. percent) and a second copolymer ethylene and a C3 to Clg higher alpha-olefin having an ethylene content of 5-80 26 mole percent (3-70 weight percent) with the ethylene content 27 of said first copolymer being at least 5 mole percent (4 wt.
28 %) more than the ethylene content of said second copolymer.
29 These ethylene copolymers can include diolefins containing about 6-28 carbon atoms, e.g. 5-vinyl-2-norbornene, as a q~9 1 third monomer. The ethylene copolymers of the mixture are 2 chosen so as to provide a weight average ethylene content 3 comparable to the characteristic modal weight percent at 4 which the pour point is at a ~aximum ~or the particular lub-ricating oil.
6 It has now been discovered that an ethylene/C3-Cl8 7 alpha-olefin terpolymer containing at least about l wt. % of 8 a Cl-~2l alkyl-substituted norbornene has improved compati-9 bility with pour point depressants and can be, if desired, 0 readily reduced in molecular weight by oxidative and mechani-11 cal degradation without deleterious formation of the oil-12 insoluble gel particles.
13 The lubricating oil composition according to this14 invention comprises a lubricating oil, at least a viscosity index-improving amount of an oil-soluble ethylene copolymer 16 having: a number average molecular weight (Mn) of at least 17 5,000; a molecular weight distribution as determined by the 1~ ratio of weight average molecular weight (Mw) to number aver-19 age molecular weight (Mw/Mn) of less than 8, and a thickening efficiency in the range of loO to 3, preferably 1.2 to 2.4, 21 when compared to polyisobutylene having a viscosity average 22 molecular weight (Mv) of 20,000; and containing 26-79 weight 23 per cent (35-85 mole percent) of ethylene, at least one C3 24 to Cl8 alpha-olefin, such as propylene, and from about l to 25~ preferably 2 to lO, weight percent of a Cl-C2l alkyl norr 26 bornene, such as ethyl norbornene, and preferably at least a 27 pour point depressing amount of a lubricating oil pour point 28 depressant. In a preferred embodiment, the etbylene co-~9 polymer is oxidatively and mechanically degraded, preferably30 by mastication in the presence of air at a temperature of l from about 95C~ to 2~0C. for from 0.25 to 20 hours whereby 2 the thickening efficiency is reduced ~rom a value greater 3 than about 3, e.g~ about 4, to within the range of 1.0 to 4 3.0, preferably from 1 2 to 2.4, and the oxygen content qf said ethylene copolymer is from about 0.005 to 6, preferably 6 0.05 to 3 wt. % based on the total weight of said copolymer.
7 The mechanically degraded and oxidized copolymer can be re-8 acted with polyamines for dispersancy whereby multifunction-9 alization is provided, i.e. said copolymer contains from abaut 0.005 to 4, preferably 0005 to 2, percent by weight of ll nitrogen, based on the total weight of said copolymer.
12 Thickening efficiency (T.E.~ is defined as the 13 ratio of the weight percent of a polyisobutyle ~ (sold by 1A Exxon Chemical Co., New York, NY as PARATONE ~ having a Staudinger ~lecular Weight of 20,000, required to thicken 16 a solvent extracted neutral mineral lubricating oil, having 17 a viscosity of 150 SUS at 37~8Co, a viscosity index of 105 18 and an ASTM pour point of -1708~C. (Solvent 150 Neutral) l9 to a viscosity of 12.4 centistokes at 98.9C., to the weight of a test copolymer required to thicken the same oil to the 2l same viscosity at the same temperature.
22 Ethylene copolymers containing ethylene, a longer 23 chain alpha--olefin, norbornene and alkenyl substituted nor-24 bornene monomers are known as V.I improvers. U.S. 3,598,738 teaches that oil-solub~e ethylene copolymers containing co-26 monomers such as C3-C12 alpha-olefins, terminally unsaturated 27 non-conjugat:ed C5oC8 diolefins, 2-norbornene and 5-methylene-28 2-norbornene and mixtures thereof can be used as viscosity 29 index impra~ers for mineral oil compositions.
In accordance with the teachings of this invention, -1 the alkyl norbornenes which are an essential class of mono-2 mers for copolymeriza-tion with ethylene and the C3-C18 higher 3 alphs-olefins are alkyl-substituted norbornenes containing 4 about 8-28 carbon atoms, preferably about 8-12 carbon atoms.
Su~table norbornene monomers include methylnorbornene, iso-6 propylnorbornene, butylnorbornene, pentylnorbornene, dodecyl-7 norbornene, octadecylnorbornene, eicosylnorbornene, etc., 8 preferably ethylnorbornene. Mixtures are also useful.
The longer chain alpha olefins which may be used o individually or as a mixture in the preparation of the ethyl-ene copolymers used in the practice of this invention are 12 those monomers containing from 3 to about 18 carbon atoms.
13 These alpha-olefins may be linear, or branched where the l4 branching occurs three or more carbon atoms from the double bond. While a single olefin is preferab]e~ mixtures of C3 16 to C18 olefins may be employed. Examples of suitable C3 to l7 C18 alpha-olefins include propylene, l-~utene, l-pentene, 1 18 hexene, l-heptene, l-octene, l-nonene, l-decene, 5-methyl-1-l9 hexene, dimethyl-l-pentene, 4-methyl-1-heptene and mixtures thereof. It is preferred, however, that the ethylene mono-21 mer be copolymerized with propylene.
22 In general, the ethylene, C3-C18 higher alpha-23 olefin and alkylnorbornene copolymers used in accordance 24 with this invention are derived from about 26 to 79% by weight of ethylene, about 20 to 73% by weight of C3-C1~
26 alpha-olefins and l to 25%, preferably 2 to 10, wto % of 27 alkylnorbornene monomers 28 Preferably the copolymers are derived from about 29 40 to 65% by weight ethylene, about 34 to 59 wt. % of a C3-C18 alpha-olefin and about 2 to 10% by weight of alkyl nor-\
~Lhl~9 1 bornene. The most preferred copolymers are derived from 2 53 wt. % of ethylene, 3~O3 wt. % of propylene and 8.7 wt. %
3 of ethylnorbornene.
4 The copolymers of this invention may be character-ized by the following properties:
6 Broad Range Preferred Range 7 Ethylene Content 26-79 wt. %40-65 wto %
8 Alkylnorbornene Content 1-25 wt %2-10 wt. %
9 Degree of Crystallinity 0-37% 0-15%
Mn X 10-3 5~300 10-70 11 Mw X 10-3 10-800 10-400 12 Mw/Mn ~ 8 6 13 Branching ~ 10 C 4 14 Mixtures of these monomers may be used, i.e. more than one higher alpha-olefin and/or more than one alkylnor-16 bornene may be employedO Other compatible components, in-17 cluding those which are copolymerizable to form tetrapoly-18 mers, may be present, etcO In no instance should the diole 19 fin content exceed 1 wto %, preferably it should be less than 0.8 wt. %, since the ethylene copolymers of this invention 21 containing an excessive amount of a diolefin cannot be use~
22 fully degraded in accordance with degradation means of this 23 inventionO
24 In general9 these copolymers can be produced by a catalyst composition which comprises a principal catalyst 26 consisting of a transition metal compound from Groups IVb, 27 Vb and VIb of the Periodic Table of the Elements, particular-28 ly compounds of titanium and vanadium, eOg VOC13, and or-29 ganometallic reducing compounds from Groups Ila, IIb and lIla, particularly organo-aluminum compounds, e.g. (C2H5)3 31 A12C13, which are designated as cocatalystsO Examples of 32 suitable catalysts and preferred reaction conditions are 33 shown in U S. Patent 3,551,336.

1 Polymerization may be effecte~ to produce copoly 2 mers by passing ethylene, aTI alpha C3-t,28 monoolefin, prefer-~ ably propylene, and the alkyl substituted norbornene mono-4 mer) preerably ethylnorborneneg and hydrogerl into a liquid 5 inert-diluent-~o:Lvent reaction medlum contain-Lng catalyst 6 and cocatalyst i.n ca~alytic amount~ The nonreac~ive reac-7 tion medium may be an ~romatic hydrocarbon such as ~oluene~
8 a sa~urated aliphatic hydrocarbon such as heptane, pentane7 9 and hexane, or a chlorohydrocarbon su h as tetrachloroethyl-lo ene. All steps in this reaction should preferably be carried 11 out in the absence of oxygen, moiskure, carbon dioxi~e^or 12 other harmful materialsO Preferably, all reac~ants an'd 13 catalysts m&y be pure and dry and blanketed with inert gas 14 such a~ nitrogenO
During polymerization, the reaction mixtllre may 16 be agitated and maintained at temperatures of -40 to lOO~Co~
7 preferab~y -10Co to ~O~C,g optimally about 30Co ~nd pres-18 sures of 0-1000 psig~ preferably 0~300 pSig9 optimally 60 19 pSig3 during a period of 1-300 minutes9 preferably 3 60 min-utes, optim~lly L5 minute80 At the end of this period, the 21 reaction mix-ture may be worked up to separate thP product 22 copolymer or t~e mixture may be used as ~uch for degradation.
23 The et~ylene copolym rs o~ the învention could be 24 alternatively produced by hydrogenation o the copolymers o the prior art which incorporate alkenyl norbornen~, e.g. 5 26 e~hyl~dene-2~orbornene, as ~he ~hird comonomerO Hydrogen 27 ation ~o remove the u~saturation of the pendant alkenyl group 28 can be readily carried out by the proce~s described in UOS.
29 3,7~5,6~5 (see Example Ljo e Og . dissolving the copolymer in cyclohexane, adding Raney niclceL as the catalyst, pres-~ 9 1 surizing the system with hydrogen to about 3600 psi by use 2 of a metal bomb; ~hereafter heating the contents at 250C.
3 for about 16 hours; and, working up the reaction mixture 4 to recover the hydrogenated copolymer. The hydrogenated copolymer can then be used as a V.I. improver or subjected 6 to oxidation-amination as further described herein.
7 OXIDATION AND MECHANICAL DEGRAD,ATION OF THE COPOLYMER
8 It has been discovered that these ethylene co-9 polymeric viscosity-index improving additives of the inven-tion can be readily degraded, i.e. reduced in molecular weight, by mastication in air such as by a mechanical shear-l2 ing machine, e.g. a Banbury mixer This process results in l3 shear stable ethylene copolymers which when incorporated 14 in lubricating oils~provide "stay-in-grade" performance which performance is important if not essential for lubri-16 cation of modern high performance enginesO
7 This finding that these materials may be masti-18 cated in a high shear machine is surprising since commer-19 cially available terpolymers having over 1 wt. % cyclic diolefin, eOg. Vistalon 2504 sold by E~xon Chemical Company, 21 Houston, Texss, or over 1 wto % linear diolefin~ eOg Nordel 22 1320 sold by ~.I. d~Pont de Nemours of Wilmington, Delaware, 2~ form oil soluble gel upon mastication in air~ This gel 24 formation is not acceptable since the oxidized-masticated terpolymers are each insoluble in mineral oil and are no 26 longer useful as viscosity modifiers.
27 The mechanical-oxidative degradation of the ethyl-28 ene copolymer may be done with a single piece of equipment, 29 or may be donle in stages It is preferred to operate in ~ é ~

g .

. . :

1 the absence of solvent or fluxing oil so the ethylene co~
2 polymer is readily exposed to air as taught in Published 3 French Application 75,23806. Useful equipment includes 4 Banbury mixers and mills having adjustable gaps, which devices may be enclosed in jacketed containers through 6 which a heating medium may be passed such as superatmos-7 perhic steam, or heated DOWTHE~ ~. When degradation has 8 reached a desired level, as determined by oxygen uptake and g reduction in thickening efficiency ~T oEo) as defined before, a fluxing oil may be added to the degraded ethylene co-11 polymerO Usually enough oil is added to provide a concen-12 trati-on-of degraded copolymer in the range of about 5 weight 13 percent to 50 weight percent based on the weight of the total 14 resulting solutionO The resulting oil solution may there-after be utilized as an article of commerce as a lubricant 16 additive or readily incorporated into the lubricating oilO
7 Useful tempera~ures for mechanical-oxidative de-1~ grading of the ethylene copolymers are in the range of about 19 95Co to 260Co The time required to achieve satisfactory results will depend on the type of degrading or mastication 21 equipment, the temperature of degrading9 and particularly 22 the speed of rotation if using a blade mixer as the degrad-23 ing or masticating deviceD In this regard, the Bramley 24 Beken Blade Mixer has been found to be particularly useful in providing in a single piece of equipment~ the desired de-26 gree of mastication or milling and oxidative degradation.
27 This mixer, which is equipped w1th a variable speed drive, 28 has two rollers9 fitted with helically disposed knives 29 geared so that one roller revolves at one-half the speed of the otherO The rollers are journaled in a jacketed reactor - -. . , . - , .

f~ ,a~

1 having two hemispherical halves in its base, which conform 2 to the radii of the two rollersO Superheated steam, or 3 heated DOWT~E ~ , may be circulated through the jacket to 4 provide th~ desired temperature. With this mixer satisfac-tory reductions in thickening efficiency may be obtained in 6 from 0.25 to 20 hours in the temperature range of about 95C, 7 to 260C.
8 Instead of using a fluxing oil, other inert sol-9 vents can be used in preparing a fluid solution of the ethylene copolymer which inert solvents inchde a liquid hy-drocarbon such as naphtha, hexane~ cyclohexane, dodecane, 12 mineral oil, biphenyl~ xylene or toluene1 a lubricating oil 13 of the solvent neutral type, 8 white lubricating oil, chlor-14 inated solvents such as dichlorobenzene, etc~ The amount of the solvent is not critical so long as a sufficient amount 16 is used to result in the fluid solution of the ethylene co-17 polymer so as to facilitate ~he mechanical oxidative degrada-18 tion. Such a solution as earlier described usually contains 19 from about 50 to about 95 weight percent of the solvent.
The oil-soluble ethylene copolymeric additives in-21 cluding the oxygen and nitrogen-containing derivatives of 22 this invention are incorporated in lubricating oil composi-23 tions, e.g., automotive or diesel crankcase lubricating oil, 24 in at least viscosity index improving amounts and generally in concentrations within the range of about l to 15 weight 26 percent, preferably 2 to 7 weight percent of the total com-27 position.
2~ Further, these oilosoluble degraded ethylene co-29 polymeric V.I. improving materials of the invention can be derivatized into multifunctional VoIo improvers by addition ~ - ~

~ 9 1 of sludge dispersant activity. ThLs is readily accomplished 2 by reaction ~ith or grafting of amine compounds into said 3 ethylene copolymeric materials.
4 Useful amine compounds for in~roducing sludge dis-persant activity include mono- and polyamines of about 2 to 6 60, e.g., 3 to 203 total carbon atoms and about 1 to 12, e.g, 7 2 to 6, nitrogen atoms in the molecule, which amines may be 8 hydrocarbyl amines or may be hydrocarbyl amines including 9 other groups, e.g., hydroxy groups, alkoxy groups, amide groups, imida~oline groups, and the like. Pre~erred amines ll are aliphatic saturated amines, including those of the gen-l2 eral formulae: r 13 R-N-R' and R-N-(CH2)~ H2)S- t -N-R
14 R" R' l H R' l$ wherein R, R' and R" are independently selected from the l6 group consisting of hydrogen~ Cl to C2s straight or branched l7 chain alkyl radicals; Cl to C12 alkoxy ~2 to C6 alkylene l8 radicals; C2 to C12 hydroxy or amino alkylene radicals; and 19 Cl to Cl2 alkylamino C2 to C6 alkylene radicals; s is a 2~ number of from 2 to 6, preferably 2 to 4; and t is a number 21 of from 0 to 10, preferably 2 to 6.
2i Non-limiting examples of suitable amine compounds 23 include mono-, di- and tri-tallow amines; 1,2-diamino-24 ethane; 1,3~cliaminopropane; 1,4-diaminobutane; 1,6-diamino-hexane; diethylene triamine, triethylene tetraamine, tetra-26 ethylene pent:amine; 1,2-propylene diamine; di-(1,2-propylene) 27 triamine; di--(l93-propylene) triamine; N,N-dimethyl-1,3-28 diaminopropane; N,N-di-(2-aminoethyl) ethylene diamine; N,N-29 di-(2-hydroxyethyl)-1,3-propylene diamine; 3-dodecyloxypro-pylamine; N-dodecyl-1,3-propane diamine, tris-hydroxymethyl ,' ~ ' 1 methylamine, diisopropanol amine and diethanol amine.
2 Other useful amine compounds include: alicyclic 3 diamines such as 1,4-di-(aminomethyl) cyclohexane, and 4 heterocyclic nitrogen compound~ such as imidazolines and N-aminoalkyl piperazines of the general formula'~
6 CH2 ~ CH2 7 NH2-(CH2)p ~ ~ \ Z

9 wherein Z is oxygen or NG and ~ is `independently selected from the group consisting of hydrogen and~Q -aminoalkylene 11 radicals of from 1 to 3 carbon atoms; and p is an integer of 12 from 1 to 4. Non-limiting examples of such amines include 3 2-pentadecyl imidazoline; N-(2-aminoethyl) piperazine; N-4 (3-aminopropyl) piperazine; N,N'-di-(2-aminoethyl~ piper-azine; and n-propyl aminomorpholine.
16 Commercial mixtures of amine compounds may advan-17 tageously be used. For e~ample, one process for preparing 18 alkylene amines involves the reaction of an alkylene dihal-19 ide (such as ethylene dichloride or propylene dichloride) with ammonia, which results in a complex mixture of alkylene 21 amines wherein pairs of nitrogens are joined by alkylene 22 groups, forming such compounds as diethylene triamine, tri-23 ethylene-tetramine, tetraethylene pentamine and isomeric 24 piperazines. Low cost poly(ethylene amines) compounds hav-ing a composition approximating tetraethylene pentamine are 26 available commercially under the trade name Polyamine 400 27 (PA-400~ marketed by Jefferson Chemical Co., New York, N Y.
28 Similar materials may be made by the polymerization of azi-29 ridine, 2-met'hyl aziridine and azetidine.
Still other amines separated by hetero atom chains .

: ' l such as polyethers or sul~ides can be used.
2 Introduc~ion of the sludge dispersant activity can 3 be by various means including: reacting the oil-soluble 4 ethylene copolymer with an oxygen-containing gas ~nd said amine compound at a temperature of from abou~ 130C. to 6 about 300~ . while mechanically degrading said copolymer ac-7 cording to the disclosure of German Patent Application No.
8 DOS 2,~05,796; forming an anion of said o~idized ethylene ~ copolymer and reacting said anion with acrylonitrile and thereafter derivatizing the reaction product with amines as ll is taught in U.S. Patent NoO 4,051,048 filed October 13, 12 1976; and, reacting said oxidized ethylene copolymer with 13 said amines as taught according to the amination procedure 14 of U.S. Patent 3,864,268 The copolymers o the invention can be employed 16 alone in lubricant compositions or they can be employed in 17 combination with other viscosity index improvers. If de-l8 sired, the copolymers may be employed in combination with 19 other additives, for example, pour point depressants such as 2Q polymethacrylates; ashless dispersants such as the reaction 2l product of polyisobutenyl succinic anhydride with tetraet~yl~
22 ene pentamine, detergent type additives such as calcium nonyl-23 sulfurized phenate and magnesium phenyl sulfonate; zinc anti-24 oxidants such ~s dialkyl dithiophosphate, etc. It is contem-plated that the invention polymers can be blended with other 26 polymers so as to impart various desired properties thereto.
27 It is a feature of this invention that significant 28 improvement i.n low temperature viscometrics may be achieved ~ without undesirable effect on pour point when a pour point depressant is present in a ormulated oil. This improvement l may be particularly noted when the lubricating oil contains 2 the pour point depressant in amount of 0.1 wt percent to 1 0 3 wt percent, preferably 0.4 wt. percent. Illustrative pour ~ point depressants which may be present in the compositlons of this invention include chlorinated wax naphthalene~ con-6 densates as described in U.S. 2,174~2~6, C10-Cl8 alkyl meth-7 acrylate polymers as described in U.S. 2,091,627 and 8 2,100,993, Clo-Clg alkyl acrylates, copolymers of di-n-alkyl 9 fumarate and vinyl acetate as disclosed in U.S. Patents 2,936,300 and 3,048,479, ethylene-vinyl acetate copolymers, ll and copolymers of styrene and alpha-ole~ins and copolymers l2 of styrene and maleic anhydride 13 In the following examples,as elsewhere in this l4 specification, all parts are by weight unless specifically lS indicated otherwise.

__ _ _ l7 - A series of ethylene-propylene copolymers contain-18 ing alkyl norbornenes were produced with varying ethylene l~ and/or alkyl norbornene, i~eO ethyl norbornene, content.
These copolymers, of which th~re are six examples~ are 21 designated hereafter as EPEN -~ through 6. These EPEN co-22 polymers are prepared from ethylene, propylene and ethyl 23 norbornene by varying the feed ratio of the three comonomers 24 i~ the polymerization process carried out essentially as 2s follows (EPE~1-5 copolymer is produced under these specific 26 conditions ~ith all parts being parts by we;ght) 3.2 parts 27 of ethylene, 4.7 parts of propylene, 0.82 parts ~f ethyl nor-28 bornene and 2 35 x (10 7) parts of hydrogen was admitted to 29 the reactor wi~h 100 parts of n-hexane, 0.009 parts of vana~
dium oxychloride and 0.032 parts ethyl aluminum sesquichlor~

' . , 1 ide. The catalyst composition was characterized by a molar 2 ratio of Al/V of 5. Residence time was about 20 minutes.
3 Polymerization temperature was 28C. and the pressure was 4 6Q psig. Steam distillation yi.elded the solvent-free ethyl-ene copolymer of the inventionu Copolymers EPEN 1-4 and 6 6 were prepared by appropriate change in the fçed stock ratio.
7 The specific compositions are set forth hereafter:
8 EPEN Wt. % Wt. ~/D Wt. % Ethyl 9 Copolymer Ethylene Propylene Norbornene 1 45.3 51.0 3.70 11 2 46.3 49,78 3.92 12 3 47.3 49.32 3.38 13 4 50.9 45.61 3.49 14 5 53.0 38.28 8.72 6 5800 32.30 9.70 17 A series of ethylene-propylene copolymers of vary-18 ing ethylene content were used for comparative purposes.
19 These 4 commercially available copolymers produced generally according to U.S. 3,697,429 are designated herein as EPC-l 21 through 4 with the following indicated compositions.
22 EPC Wt. % Wt. %
23 Copolymer Ethylene p~y~
24 1 57.5 42.5 25 2 55.4 44.6 26 3 53.0 47.0 27 4 51.5 48.5 29 In this example, a comparison of oil blend char-~0 acteristlcs of a reference oil containing the copolymers of 31 the invention, i.e. EPEN 1-6, is made with samples of said ~ 9 1 oil containing the ethylene-propylene copolymers of the prior 2 art, i.e. EPC-1-4, The reference oil is a mixture of 300N
3 and 150N base oils blended with about 0.25 wt. % active in-4 gredient (a.i.) of a commercially available alkyl fumarate-S vinyl acetate copolymer pour depressan~. Table I illus-6 trates the effect of both types of ethylene copolymers on 7 the blend characteristics of said reference oil when suffic-8 ient copolymer is added to provide a 98.9C, viscosity of 9 about 12.4 centistokes.

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1 A comparison of the pour points of Oil Blends 2 G-J illus~rates the teachings of U.S. 3,697,429 that there 3 is a characteristic model weight percent ethylene content 4 of the ethylene copolymer VoI~ improver (for this reference oil at about 57.5 wt. % ethylene) at which the pour point ls 6 a maximum. It is believed that this result occurs, at 7 least in part, because the ethyLene-propylene copolymer V.I.
8 improvers lnterfere with the operation of ronventional lu-9 bricating oil pour point depressants. In contrast, the pour points of Oil Blends A-F illustrate the advantage of 11 the ethylene copolymers of this instant invention over the 12 prior art ethylene-propylene copolymer V.I. improvers. It 13 is apparent that none of the ethylene copolymers, i.e. EPEN
14 1-6, provoke a pour point elevation due to ~he above-described interactions as a function of ethylene content, 16 in fact, a comparison of EPEN-6 with EPC-l both which have 17 an ethylene content of about 58 wt.% shows a pour point im-18 provement of about 35Fo lg EXAMPLE 2 .
In this example~ the reference oil of Example 1 is 21 replaced with a Solven~ 150N high pour base stock in order 22 to again compare the influence of the copolymers of the in-23 vention with the ethylene-propylene copolymers of the prior 24 art on the blend characteristics of another base stock con-taining the pour depressant of Example 1.

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~1 1~1 H H H H 1--1 H H ~ H H H H H H H H ~ H 1-1 H 1--1 H
O

~ 9 1 Table II illustrates that again thè ethyl-2 ene-propylene copolymer V.I. improvers ~levate the pour 3 point of the nominally pour point depressed base stock 4 (compare Oil Blend II-G' with Oil Blend II~K") whereas the ethylene copolymers of the invention generally (except ~or 6 EPEN-6) do not interfere with the operation of eonventional 7 lubricating oil pour point depressants. Again, a compari-8 son of Oil Blend II-I with Oil Blend II-E (both of which 9 have V.I. improvers which contain 53 wt. % ethylene) shows that th~ ethylene-propylene copolymer detrimentally effects 11 the blend pour points by increasing it at least 30F.;
12 whereas, the e~hylene copolymer of the invention does not 13- interfere (a blend pour point advantage for the same ethyl-14 ene content copolymers of at least 30Fl when practicing this invention).

.
17 In this axample, the commercial utility of this 18 instant invention in a commercial base stock corresponding 19 to a Pennsylvania oil having a ~15F. pour point blended .. . .
with 0.15 wt. % pour depressant and 9 wt. % detergent inhi-21 bitor package is illustrated by comparison with a commer-22 cially available ethylene-propylene copolymer V.I. improver 23 (Paratone 715 sold by Exxon Chemical Co., Houston, Texas~.
24 The resulting lOW/40 multigrade blends were prepared by ad-dition of sufficient V.I. improver to provide a 98.9C. vis-26 cosi~y of about lS centistokes. The results are shown in 27 Table III.

~o~
vr~
- o~ u~ n n o ~ . I - I i .

p~_ H¦ V .!~ C~
o ~1 ~ ~I C~ ~D O O
~q ~ I~ o W O a~ . O . . . .
U ~oo ~ U~
P~ ~ ~ ~ ~I ~I
.~ ~

Z
' ~ ~ ~4 V ~
~4 H 1~ i H H
O H ~1 1 ,~ n ~ r~ ~o _~

2 In this example, an ethylene copolymer of this in-3 stant invention is oxidatively and mechanically degraded by 4 mastication in air without ~el formation. In contrast, mastication in air under similar conditions of Vistalon 2504 6 and ~ordel 1320 results in gel formation as seen in Table IV.

~1:
:

.

. _ .___ ., .. . ., .. ; ~. , .

.

~ u~
o ro ',o ~o rl oo ~
o ~ u~
~ ~ ~ c~ .
~l ~

$ o a~ ~ ''I ~ ,, .
~G ~ ~ ~ ' ~ ~rl ~ ~rl 00 ~ ~
~ ¢ l~ o ~ ~

.
P ' :~
w ~,, o v ~ ~ oo u~ o o ~ ~' o ~ U ~n C.
,~ D o .Y
O ~ ~ ~
...

- 2~

.
2 Illustrative of a process for preparing the ami-3` nated derivative of the oxidized ethylene copolymer of the 4 invention, the masticated in air ethylene-propylene-ethyl norbornene copolymer of Example 4 can be dissolved in Sol-6 vent 100~ oil to about 7 wt.%o 25 grams of this oil solu-7 tion is condensed with 0.7 grams of tetraethylene pentamine 8 at 2 hours at 160C. while stripping with nitrogen. The 9 product copolymer will have not only V.I. improving proper-ties but also sludge dispersant activity.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A lubricating oil composition comprising a major amount of lubricating oil and a viscosity index improving amount of an oil-soluble ethylene copolymer having an ethylene content of 26-79 weight percent (35-85 mole percent), and of a C3 to C18 higher alpha olefin and from about 1-25 weight percent of an alkyl norbornene having from about 8 to 28 carbons, said ethylene co-polymer having: a number average molecular weight (?n) of at least 5,000; a molecular weight distribution as determined by the ratio of weight average molecular weight (?w) to number average molecular weight (?w/?n) of less than 8; and, a thickening efficiency in the range of 1.0 to 3 when compared to polyiso-butylene having a viscosity average molecular weight (?v) of 20,000.

2. A lubricating composition according to claim 1 wherein said ethylene copolymer has a (?w/?n) ratio of less than 6, a thickening efficiency of 1.2 to 2.4 and a (?n) of from about 10,000 to 70,000.

3. A lubricating oil composition according to claim 1, wherein said alkyl norbornene is ethyl norbornene and said alpha-olefin is propylene in an amount ranging from 6 to 73 weight percent.

4. A lubricating oil composition according to claim 1 or 3 wherein the ethylene copolymer has an oxygen content ranging from 0.005 to 6 weight percent and a nitrogen content ranging from about 0.01 to 0.5 weight percent.

5. A lubricating oil composition comprising a major amount of lubricating oil and a viscosity index improving amount of an oil-soluble oxidatively and mechanically degraded ethylene copolymer having an ethylene content of from about 26-79 weight percent ethylene, from about 1.0-25 wt. %, of a C1-C21 alkyl norbornene and the balance being at least one C3 to C18 alpha-olefin, said copolymer having a number average molecular weight (?n) of at least 5,000; a molecular weight distribution as determined by the ratio of weight average molecular weight (?w) to number average molecular weight (?w/?n) of less than 8; and, a thickening efficiency in the range of 1.0 to 3, when compared to polyisobutylene having a viscosity average molecular weight (?v) of 20,000 and, an oxygen content of from about 0.005 to 6 wt. %
based on the total weight of said copolymer.

6. A lubricating composition according to claim 5 wherein said ethylene copolymer has a (?w/?n) ratio of less than 6, a thickening efficiency of 1.2 to 2.4 and a (?n) of from about 10,000 to 70,000, and an oxygen content of from about 0.05 to 3 weight percent.

7. A lubricating composition according to claim 1 or 5 wherein said higher alpha-olefin is propylene, said alkyl nor-bornene is ethyl norbornene and said composition contains at least a pour depressing amount of a lubricating oil pour depressant.

8. A composition according to claim 5, wherein said copolymer is reacted with an amount of an amine compound selected from the group consisting of nitrogen compounds having the general formulae:
;and wherein R, R' and R" are independently selected from the group consisting of hydrogen; C1 to C25 straight or branched chain alkyl radicals; C1 to C12 alkoxy C2 to C6 alkylene radicals; C2 to C12 hydroxy alkylene radicals; C2 to C12 amino alkylene radicals;
C1 to C12 alkylamino C2 to C6 alkylene radicals; Z is 0 or NG;
G is from the group consisting of hydrogen and .OMEGA.-amino alkylene radicals of from 1 to 3 carbon atoms; s is a cardinal number of from 2 to 6; t is a cardinal number of from 0 to 10; and p is an integer of from 1 to 4 sufficient to provide a nitrogen content of said copolymer ranging from about 0.01 to 0.5 weight percent.

9. A composition according to claim 8 wherein said amine compound is an alkylene polyamine containing from 2 to 6 nitrogens per molecule.

10. A composition according to claim 8 or 9 wherein said ethylene copolymer comprises the reaction product obtained by masticating in air an ethylene copolymer having an ethylene content of from about 26 to 79 weight percent, from about 20 to 73 weight percent of C3-C18 alpha-olefins and from about 1 to 25 weight percent of alkylnorbornene and a thickening efficiency greater than 3Ø