CA1200235A - Oil compositions containing ethylene copolymers - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A lubricating oil composition comprising a major amount of mineral oil of lubricating viscosity and at least a viscosity index-improving amount of an oil soluble, saturated ethylene copolymer, preferably an and mechanically degraded ethylene copolymer, having an ethylene content of 26-79 wt. % (35-85 mole %), a C3 to C18 higher alpha-olefin and from 0.05 to 3.0, optimally 0.2 to 0.8, wt. % of 2,5-norbornadiene 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 as compared to the same formulation using an ethylene copolymer not containing 2,5-norbornadiene.

Description

1 This invention relates to improvements in the vis-

2 cosity properties of mineral oils o lubricating viscosity

3 by the addition thereto of certain satura~ed ethylene copoly-

4 mers which provide said mineral oil with excellent low tem-

5 perature viscometric properties as compared to those of other

6 ethylene copolymeric viscosity-index improvers.

7 Recently, ethylene-propylene copolymers have become

8 wldely used as viscosity improvers in lubricating oils be-

9 cause of the low treat levels and impro~ed viscometric prop-

10 erties. However, the market re~uires diffexent molecular

11 weight grades, which have different degrees of thickening

12 effec~ (usually called Thicken;ng Efficiencies or T.E.3 so as

13 to be operable with different ViSGosity mineral oils. Although

14 the preparation of each of such copolymer grades can be by

15 direct synthesis, the different molecular weight grades can

16 be produced by degradation of an ethylene-propylene copolymer

17 so as ~o produce lower molecular weight versions. It is ad-

18 vantageous to use the deg~adation approach since it is more

19 economical to make a large ru~ o~ copolymer in a large-scale

20 polymer plant, and then .o use the copolymerlc produce of

21 said run as a base material which is ~hen broken down in~o

22 lower molecular weight grades în order to meet requirements of

23 the viscosity inde-x improver market. There are various means

24 to achieve such degradation including: (a) heating an amor-

25 phous rubbery ethylene-propylene copolymer for 3 to 30 minuces

26 at from 260 LO 420C- with the exclusion of air; (b) extruding

27 and heating an ethylene copolymer first at 15~-28GC. until

28 molten and then at a temperature of 300-500C. with the ex-

29 clusion of air; and (c) by oxidative and mechanical degrada-3G ~ion~ as by mastication~ o~ ethylene-propylene copolymers in O~Z3 1 an oxygen-containing environmenc which copolymers are pref-2 erably free oi other monomers, such as dienes (see U.S~ Pacent 3 3,769,216).
4 It is known chat ethylene terpolymers which con-5 tain dienes, e.g. 5-vinyl-2-norbornene or ethylene tetra-6 polymers which contain both 1~4-hexadiene and 2~5-norborna-7 diene are not suitable for mechanical degradation as by masti-8 cation in the presence of air or oxygen whereby oxidacion 9 occurs, since chis degradatioTI technique produces excessive 10 amounts of polymerie gel part:Lcles which are oil-insoluble.
llThiS problem has been overcome by use o an ethylene copolymer 12 containing also a C3 to C18 higher alpha-olefin and from 1 to 13 25 wt.% of an alkyl norbornene having from 8 to 28 carbons 14 (see German DOS 28 15 427, published October 19, 1978).
The patent literature is replete with many publica-16 tions dealing with ethylene tri- and cetrapolymers con~aining 17 one or more types of dienes introduced for a variety of reasons 18 including a means to introduce branchiness into the echylene l9 polymer and to provide a means for crosslinking said polymer 20 through introduction of a crosslinking agent reactive wich a 21 portion of said diene, e.g. see U.K. Pacenc Specification 22 1,195,625. Those patents, however, dealing wich ethylene cri-23 and tetrapolymers added to a mineral oil as a viscosicy index 24 modiying additive are of limited number and are besc illus-25 trated by the specification of U.S. Patent 3,79C,480. This 26 specification teaches of e~hylene ter- and tetrapolymers in-27 volving ethyleneJ a C3 to C18 higher alphaolefin, for example, 28 propylene, and two classes of dienes based upon the relative 29 polymerizabilities of each of che double bonds. In one class of

30 dienes (as represented by 1,4-hexadiene), only one of che double

31 bonds is readily polymerizable whereas in the ocher class (as

32 represented by 2,5-norbornadiene), boch double bonds are

33 readily polymerizable. It is taught therein that an echylene

34 polymeric viscosity index additive for mineral oils is super-3s ior when and if it is an ethylene cetrapolymer containing both 36 classes of dienes ra.her chan t1le prior arc e:hylene cerpolymer ,.L~OV2;3' l containing the class of dienes having only one readily poly-2 merizable double bond. Apparen~ly, this superioricy obcains 3 because the introduction of the second diene comonomer wi.h 4 two readily polymerizable double bonds inco the terpolymer 5 composition provides a significant increase in bulk polymer 6 viscosity with only a minor increase of ~he inherent ViSCosiLy 7 (see col. 8, lines 23-30) ancl wichouc degradation of the pro-8 perty of ~he terpolymer ~o pxovide viscosi~y index improvement 9 to mineral oils. The only discussion of the low cemperature 10 viscometrics of mineral oil solucions containing chis cype of 11 ethylene cerpolymer is se- forth in col. 10, lines 1-3 wherei.n 12 it is scated that they gave sa~isfaccory resulcs for lOW3G
13 multigrade lubricating oils.
14 U.S. Patents 3J499,741 and 3,681,302 discuss ethylene 15 terpolymers containing a minor smount of a nonconjugaced diene 16 which are usefully thermally cracked to provide a pour point 17 depressant additive for "fuel oils, diesel oils, middle dis-18 ~illates and ocher viscous hydrocarbon oils" (see col. 1, 19 first paragraph of specifications)~ The aforesaid terpolymer 20 is also useful as an additive for gasoline to modify induccion 21 system deposits (see col. 1, lines 23-25 of '741). The 9 22 specified nonconjugated dienes include 2,5-norbornadiene, i.e.
23 bicyclo [2,2,1] hepta-2,5-diene] (see col. 2, line 36 of '3C2 24 also col. 2, lines 29-3C of '741) although the invention is 25 specifically illustraced only wich thermally cracked, urlsac-26 uraLed ethylene-propylene-hexadiene-1,5 and ethylenepropylene-27 cyclopentadiene terpolymers.
28 Unsaturation in a polymeric viscosi~y index improv-29 ing addicive is generally undesirable since the unsacura.ed 30 moiety, i.e. the double or criple bond of the polymer represenLs 31 a means by which the desired propercies of che addicive can be 32 degraded during the lubrica~ion of he engine, e.g. as by 33 cleavage of the high molecular polymer into fragmencs no longer 34 possessing viscosity index modifying properties or by cross-

35 linking of said polymer to a molecular weighc which is no

36 longer mineral oil-soluble provoking ics precipiLacion onco 1 interior engine surfaces as a varnish and/or concributing ~o 2 engine lubrica.ing oil sludge.
3 It is an object of this invencion to provide a 4 saturated ethylene copolymeric viscosity index improver for 5 mineral oils of lubricating viscosity of excellent low tem-6 peracure viscometrics, preferably one thac can be readily 7 oxidatively degraded co a lower rnolecular weighc in order to 8 achieve maximum operational properties.
9 It has been discovered that an e~hylene/C3-C18 10 alpha-olefin terpolymer containing from 0.05 to 3.0, pre-11 ferably 0.05 to 1. SJ more preferably 0.1 to 1 0, opcimally 12 0.2 to 0.8, wt.% of 2,5-norbornadiene (bicyclo ~2.2.1] hepLa-13 2,~-diene) is saturated, readily processable and provides to 14 mineral oil of lubricating viscosity improved low ~empera.ure 15 viscometrics~ has compatibility in solutions of said mineral ]6 oil with pour point depressants and can be, if desired, 17 readily reduced in molecular weight by oxidacive degradation 18 without deleterious formation of oil-insolube polymeric gel 19 particles.
The lubricating composicion of -.his invention com-21 prises a mineral oil of lubricating viscosicy and at least 22 a viscosity index-improving amo~nt of an oil-soluble ethylene 23 copolymer having a number average molecular weight (Mn) of at 24 leas~ 5,000, preferably from lO,GOG ~o 10~,000, a ,hickening 25 efficiency in the range of l.G ~o 3, preferably 1.2 to 2.8 26 and containing 26-79 weighc percenc (35-85 mole percenc) of 27 ethylene, a~ least one C3 to C18 alpha-olefin, such as propy-28 lene, and from 0.05 to 1.5, preferably 0.1 ,o l.G, weighc per-29 cent of 2,5-norbornadiene (said weighc percencs totaling lGC), 30 and preferably at least a pour point depressing amount of a 31 lubricacing oil pour poin~ depressanc.
32 In a preferred embodimenc, ,he echylene copolymer is 33 oxidatively and mechanically degraded, preferably by mas,ica-34 tion, in Lhe presence of air a~ a .emperacure of from abouL
35 95C. ~o 260C. for from 0.25 to 2C hours whereby the thick-36 ening efficiency is reduced from a value grea.er than abou~ 3, lZ~Z~3 l e~g~ about 4, to wi~hin he range of l.0 LO 3.0, preferably 2 from 1.2 to 2.8, and the oxygen concent of said ethylene 3 copolymer is from abou~ O.C05 to 6 wt.%, preferably 0.~5 to 4 3 wt.~/o, based on che tocal weigh~ of said copolymer.
S The mechanically degraded and oxidized copolymer 6 can be reacGed with polyamines ior dispersancy whereby mulci-7 functionalization is provided, i~e. s~id copolymer contai~s from 8 about 0.005 to 4, y~eerably 0.05 to 2, percent by weight of 9 nitrogen, ba~ed on the total weigh~ of said copolymer.
Thickening ef~iciency (T~E.) is defined as the racio 11 of the weight percenc of a polyisubutylene (sold by Exxon 12 Chemical Co., New York, N.Y~ as ~ARATONE ~) having a Staud-13 inger Molecular Weighc of 20,00G required to chicken a solvenc-14 extrac.ed neutral mineral lubricacing oil, having a viscosity 15 of 150 SUS a~ 37.8C., a viscosicy index oE 105 and an ASTM
16 pour point of ~17.8C., (Solvent 150 Neucral~ to a viscosity 17 of 12.4 centiscokes at 98.9C., co the weight of a cesL copoly-18 ~er required to ~hicken the same oil co Lhe same ViscosiLy at l9 the same cemperacureO
Generally, the amoun~ of the copolymer added co said 21 mineral oil ranges from Col to 15, preferably 0.2 ~o 7, weight 22 percent ba ed on the to.al weighc of che lubrica~ing com-23 position~ ~~
24 Ethylene te~rapolymers containing ethylene, a longer 25 chain alpha-ole~in, 1,4-hexadiene and 2,5-norbornadiene mono-26 mers are kno~l as V.I. improvers for mineral oil composicions 27 which ~etrapolymer provides suitable low ~emperature perform-28 ance and is itself readily processable though ic is an un-29 saturated copolymer.
In accordance wi~h the teachings of chis invencion, 31 2,5-norbornadiene appears ~o copolymerize wi.h e,hylene and 32 the C3-Cl~ higher al~ha-olefins in a manner so as .o provide a 33 readily processable sa~uraced copolymer, i.e. wich an iodine 34 number less ~han Co8 which is indiscinguishable from che copoly-35 mer con,aining no diolefin wich long-chain branching, whereby 36 ~he cerpolymer's addicive ac~ivi,y in mineral oil provides for * TRADl~ MARK
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l excellent low temperacure viscometrics and yec as needed said 2 terpolymer can be mascic~ced co a T.E. so as co provide for 3 enhanced shear stability of che additive for said mineral oil.
4 Although noc being bound by cheory ic appears cha L
the 2,5-norbornadiene serves multiple roles providing long 6 chain branching, which is desirable as discussed in the prior 7 ar~, and by acting tO reduce the length of echylene sequences 8 in the polymer chain which ultimately reduces agglomeracion 9 and lowers oil solution viscosity at low temperature. It 10 appears likely thac the 2,5-norbornadiene encers che chain by ll more than one mechanism; one of which does noc lead LO branch-12 ing The absence of residual olefin, i.e. unsaLuracion per-13 mics oxidacive masticacion co reduce molecular weighc. Only 14 the 2,5-norbornadiene scructure appears capable of performing 15 these varied functions. For the purpose of forming long-chain 16 branches and leaving no olefinic residue boch double bonds 17 should be readily polymerizable. For the purpose of reducing 18 ethylene sequence lengths tche olefin should be sterically 19 hindered enough to polymerize wich ethylene only and noc 20 higher alpha-olefins, and should readily polymerize wich echyl-21 ene with an effec~ive re ccivi~y ratio product near zero.
22 (See F. P. BaldwinJ G. Ver Strace, ~ubber Reviews, 44, 7G9 23 ~1972) for a definition of reaccivity racio product and kinetics 24 data on various struccures).
Since gellation in a concinuous flow stirred reaccor 26 should occur after incorporation of a diene mole fraction equal 27 to 1/(2DPw) (where DPw is the weighc average degree of poly-28 merizacion in the absence of diene) and this number for the 29 polymers of Example 1 is ca. .01%, which is far exceeded by 30 chose polymers, chere musc be mulciple polymerization mech-31 anisms. It appears likely that che 2,5-norbornadiene encers 32 the chain formirg a norcricyclone scruccure; similar sLruc-33 tures appear possible wich vinyl l-cyclohexene so cha~ coo 34 may be conformed chrough experimencation co provide a com-35 parably unique and valuable cerpolymer as one obcains wich the 36 terpolymer described in chis invencion. This chain s-ruccure 3s~j l may amoun~ to as much as 9G% of the 2,5-norbornadiene incorp-2 oration in~o the polymer. Wi~houc this cwoEold polymerizacion 3 mechanism inadequa.e diene could be incorporaced inco the 4 polymer to significantly influence ,he sequence distribucioll.
The longer chain alpha-olefins which may be used 6 individually or as a mixcure in the preparacion of he ethylene 7 copolymers used in the prac~ice of chis inven~ion are those 8 monomers concaining from 3 ~o abouc 18 carbon a.oms These 9 alpha-olefins may be llnear, or branched where ~he branching 10 occurs three or more carbon acoms from che double bond. While ll a single olefin is preferableJ mixcures of C3 o C18 olefins 12 may be employed. It is preferred~ however, ~hac the e~hylene 13 monomer be copolymerized with propylene.
14 In general, the e~hylene, C3-C18 higher alpha-olefi~
15 and 2,5-norbornadiene copolymers used in accordance with 16 chis inven~ion are derived from abouc 26 co 8C% by weight of 17 ethylene, abouc 2~ .o 74% by weighL of C3~C18 alpha-olefins 18 and 05 to 3.0 preferably 0.05 to 1.5, wc % of 2,5-norborna-19 diene, che laLter being the sole diene used.
Preferably the copolymers are derived from about 21 40 to 65% by weight ethylene, abouc 35 to 60 wt.% of a C3-C18 22 alpha-olefin and about 0.2 ,o l.C% by weighc of norbornadiene.
23 The most preferred copolymers are derived from 43 wc.% of 24 ethylene, 56.2 wt.% of propylene and ~.8 w~% of norbornadiene.
The copolymers of ~his inven~ion may be charac~er-25 ized by the following propercies;

~ . .

2 Broad Preferred Me~sured 3 Range Range By 4 Ethylene Content 26-79 wt.% 4Q-65 wt.% lnfrared 5 2,5-Norbornadiene Content 0.05 - 1.5 w~.% 0.1-1 ~ wt.~ *
6 Degree of Crystallinity 0-37~ Q-15~ X-Ray 7 Mn X 10 3 5-300 lQ-70 *~
8 M~J X 10 10-800 10-400 light scattering ~ p~
, e 10 ~*Membrane Osmometry 11 *Analysis for 2,5-norbornadiene is difficult due to the absence 12 of easily identifiabIe spectral peaks of adequate intensity.
13 Use of refractive index, a technique well known (I. J. Gardner, 14 G. Ver Strate, Rubber Chem. Tech., 46, 1019 (1973~ for similar dienes, indicates extensive incorporation. The absence of un-16 saturation in the copolymer by iodine number indicates complete 17 utilization of the second olefinic residue, which should poly-18 merize more difficultly than the first, therefore 100% conversion 19 of the feed is likely. The contents have been calculated on that basis.

1 These copolymers can be produced by a cacalysc com-2 posi~ion which comprises a principal catalysc consiscing of a 3 transicion mecal compound from Groups IVb, Vb and VIb of the 4 Periodic Table of che Elements, particularly compounds of 5 titanium and vanadium, e.g. V()C13, and organomecallic reducing 6 compounds from Groups IIaJ IIb and IIIa, parcicularly organo-7 al~minum compoundsJ e.g. (C2H5)3A12C3, which are designa~ed 8 as cocatalysts. Examples of suitable catalysts and preferred 9 reaction conditions are shown in U.S. Patenc 3,551,336.
Polymerization may be effec~ed to produce copolymers 11 by passing echylene, alpha C3-C28 monoolefin, preferably 12 yropylene, 2J5-norbornadiene and hydrogen inco a liquid inert-13 diluent-solvent reaction medium containing ca-alyst and co-14 catalyst in cacalytic amounts. The nonreactive reaction med-15 ium may be an aromatic hydrocarbon such as toluene, a sac-16 urated aliphatic hydrocarbon such as heptane, pentane, and 17 hexane, or a chlorohydrocarbon such as ~etrachloroethylene.
18 All steps in this reaction should preferably be carried out in l9 the absence of oxygen, moisturel carbon dioxide or other harm-20 ful materials.
21 During polymerization, the reaccion mixture may be 22 agitated and maincained at temperatures of -40 to l~CC., 23 preferably -lCC. to 70C., optimally about 30C. and pressures 24 of O-lOCO psig, preferably 0-300 psig, opcimally 60 psig, 25 during a period of 1-300 minuces, preferably 3-60 minutes, 26 optimally 15 minutes. At the end of chis period, che reaction 27 mixture may be worked up co separate the producc copolymer or 28 the mixture may be used as such for degradation.
29 It has been discovered that thes~ ethylene copolymeric 30 viscosity-index improving additives of the invention can be 31 readily degraded, i.e. reduced in molecular weigh~, by masci-32 cation in air such as by a mechanical shearing machine, e.g.
33 A Banbury mixer. This process results in shear scable 34 ethylene copolymers which when incorporated in lubricating oils 35 provide "stay-in-grade" performance which performance is im-36 portant if not essencial for lubricacion of modern high per-S

1 formance engine~.
2 This f~ndin8 that chese macerials may be mastica~ed 3 in a high shear machine is surprising since commercially 4 available ~erpolymers having over 1 wt .Vz cyclic diolefin, e.g.
5 Vistalon 2504*sold by Exxon Chr~;C~l~ Hous~on, Texas (ethy~
6 lene~propylene-2,ethylidene~ norbornene terpolymer) or 7 tetrapolymers having over 1 w~.% linear diolefin, e.g. Nordel 8 1320*sold by E. I. duPont de Nemours of Wllming~on, Delaware 9 ~e~rapolymer of ethylene propylene-1,4-hexadiene and 2,5-nor-lO bornadiene) form oil insoluble gel upon mastica~ion in air.
11 This gel formati.on is not acc:eptable since che oxidized-mas~i-12 cated ~erpolymer~ are each insolubLe in mineral oil and are no 13 longer useful as viseosicy modi~iers.
14 For the purposes of ~hls invencion, ~he mechanical-15 oxidative degradation of ~he ethyLene copolymer may be done 16 with a single pieee of equipment, or may be done in scages. It 17 is preferred ~o operate i~ che absence of solvent or fluxing 18 oil so tha~ ethylene copolymer is reatily ~xposed tO air as l9 taught in ~n~dl~ Patent 1,072,246. Useful equlpment in-20 cludes Banbury mixers and mills having adjus~able gaps, whirh 21 devices may be enclosed in jacke~ed concainers through which 22 a heating medium may be passed ~uch as superac~ospheric steam, 23 or heated DOWTHE ~ . When degradation has reached a desired 24 level, as determined by o~gen uptake and reduction in ~hick-25 ening efficiency (T.E.~ as defined before, a fluxing oil may 26 b~ added to the degraded e~hylene copolymer. U~ually enough 27 oil is added to provide a concentration of degraded copolymer 28 i~ the range of about 5 weight percent co 50 weighc percent 29 based on ~he weighc of the ~ocal resulcing solucion~ The 30 resulting oil soluLion may ~hereafter be ucilized as an arcicle 31 of commerce as a lubricanL addi.ive or readily lncorpora~ed inco 32 che lubricacing oil.
33 Useful tempera~ures for mechanical-oxidative degrading 34 o~ the echylene copolymers are in .he range of about 95C. co 35 260C. The ~ime requ~red ;o achieve sa.isfac;ory resul~s t~ill 36 depend on .he type of degrading or mascieacion equipment, .he * TRADE MARK
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1 temperature of degrading, and particularly the speed of ro-2 tation if using a blade mixer as che degrading or mastica,ing 3 device. In this regard, che Bramley Beken Blade Mixer has 4 been found to be par~icularly useful in providing in a single 5 piece of equipment, che desired degree of mas~ication or 6 milling and oxidative degradation. This mixer, which is 7 equipped with a variable speed drive, has cwo rollers, fitced 8 with helically disposed knives geared so ~hac one roller re-9 volves at one-half the speed of the ocher. The rollers are 10 journaled in a jacketed reac.or having two hemispherical halves 11 in its base, which conform to the radii of che ~wo rollers.
12 Superheated steam, or heated DOWTHE ~ , may be circulated 13 through the jacket co provide the desired temperature. With 14 this mixer satisfac~ory reduccions in thickening efficiency 15 may be obtained in from 0.25 to 20 hours in the temperacure 16 range of about 95C. to 260C.
17 Instead of using a fluxing oil, other inert solvencs 18 can be used in preparing a fluid solution of the ethylene co-19 polymer which inerc solvents include a liquid hydrocarbon 20 such as naphcha, hexane, cyclohexane, dodecane, mineral oil, 21 biphenyl, xylene or toluene, a lubricating oil of the solvent 22 neutral type, a white lubricating oil, chlorina~ed solvents, 23 such as dichlorobenzene, ecc The a~ount o~ the solvent is not 24 critical so long as a sufficienc amount is used to resulc in 25 the fluid solution of the ethylene copolymer so as to facili-26 ta~e the mechanical-oxidative degradation. Such a solution 27 as earlier described usually contains from about 50 co about 28 95 weight percent of the solvent.
29 The oil-soluble ethylene copolymeric addicives in~
30 cluding the oxygen and nitrogen-containing derivatives of this 31 invention are incorporaced in lubricacing oil composicions, 32 e.g., automative or diesel crankcase lubricating oil, in at 33 least viscosity index improving a~ounts and generally in 34 concentracions within the range of abouc 0.1 ro 15 weighc per-35 cent, preferably G.2 to 7 weight percenc of the cotal com-36 posicion.

t~

l Further, chese oil-soluble degraded e~hylene co-2 polymeric V.I. improving materials of the invention can be 3 derivatized into multifunc~ional V.I. improvers by addition 4 of sludge dispers~nt activity. This is readily accomplished 5 by reaction with or graf~ing of ami~e compounds in.o said 6 ethylene copolymeric materials of the invention.
7 Useful amine compounds for in~roducing sludge dis-8 persant activity include mono- and polyamines of abou~ 2 to 60, g e,g. 3 to 20, total earbon at:oms and abouL 1 to 12, e.g. 2 to 10 6, nitrogen atoms in the molecule, which amines may be hydro-ll carbyl amines or may be hydrocarbyl amines including other 12 groups, e.g. hydroxy groups, alkoxy groups, amide groups, 13 imidazoline groups, and .he like. Preferred amines are 14 aliphatic satura~ed amines, including those of the general 15 formulae: - ~
16 R-N-R' and R-N-(CH2~s- -N-(CH2)S- -p-R
17 R" ~ _ ~ t R~
18 wherein R, R' and R" are independencly seLec~ed from the group 19 consisting of hydrogen; Cl ~o C25 straigh~ or branched chain 20 alkyl radicals; Cl to C12 alkoxy C2 to C6 alkylene radicals;
21 C2 to C12 hydroxy or amino alkylene radicals; and Cl to C12 22 alkylamino C2 to C6 alkylene radicals; 5 iS a number of from 23 2 to 6, preferably 2 to 4; and t is a number of from O to 10, 24 preferably 2 to 6.
Examples of suitable amine compounds include mono-, 26 di- and tritallow amines; 1,2-diaminoethane; 1,3-diamino-27 propane; 1,4-diaminobucane; 1,6-diaminohexane~ diethylene 28 triamine, triethylene cetraamine, i~etrae~hylene pen.amine;
29 lJ2-propylene diamine; di- (1,2-propylene) ~riamine; di-~1,3-30 propylene) triamine; N,N-dimethyl-1,3-diaminopropane; N7N-dip 31 (2-aminoethyl) e~hylene diamine; N,N-di-(2-hydroxyethyl)-1,3-32 propylene diamine; 3-dodecyloxypropylamine; N-dodecyl-1,3-pro-33 pane diamine, trishydroxymethyl methylamine, diisopropanol 34 amine and diethanolamine.
Other useful amine compounds include: alicyclic 36 diamines such as 1,4-di-(aminomethyl) cyclche.~ane, and heter-1 ocyclic nitrogen compounds such as imidazolines and N-amino-2 alkyl piperaæines of che general formula:
3 ~H2 C~2 12(CH2~p - N Z
CH2 C~2 6 wherein Z is oxygen or NG and G is independently sqlec~ed from 7 the ~;roup consisting of hydrogen and Q -aminoalkylene radicals 8 of from 1 to 3 carbon atoms; and p is an integer of Erom 1 to 4.
9 Nonlimiting examples o such amines include 2-pentadecyl imid-10 azoline; N-(2-aminoethyl) piperazine; N-(3-aminopropyl~ piper-11 azone; N,N'-di-(2-aminoethyl) piperazine; and n-propyl amino-12 morpholine.
13 Commercial mixtures of amine compounds may advan-14 tageously be used. For example, one process for preparing 15 alkylene amines involves the reaction of an alkylene dihalide 16 (such as e~hylene dichloride or propylene dichloride) with 17 ammo~la, w~ich results in a complex mixture of alkylene amines 18 wherein pairs of nicrogens are joined by alkylene groups9 lg forming such compounds as die~hylene triamine, ~riethylene-20 tetramineJ cetraethylene pentamine and isomeric piperazines.
21 Low cost poly (ethylene amines) compounds having a composition 22 approxima~ing tetraethylene pentamine are available commercially 23 und~r the trade name Polyamine 400*(PA-400) marketed by 24 Jefferson Chemical Co., New York, NY. Similar materials may 25 b~3 made by the polymerization of aziridine, 2-m~thyl aziridine 26 and aæetidine.
27 Still o~her amines separaced by hecero atom chains 28 such as polyethers or sulfides ean be used.
29 Introduction of the sludge dispersant accivity can 30 be by various means including: reacting the oil-soluble 31 ethylene copolymer wich an oxygen-containing gas and said 32 amine compound ac a cemperature of from abou~ 130C. .o about 33 300C. while mechanically degrading said copolymer forming an 34 anion of said oxidized echylene copolymer and reac-ing said 35 anion with acryloni~rile and ~-hereafcer derivi~izing che 36 reaccion product wich amines; and, reacting said oxidized * TRADE MARK
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~, 1 ethylene copolymer with said amines alone in lubricanL com-2 positions which is predominantly a mineral oil of lubricating 3 viscosity or they can be employed in combination with other 4 viscosity inde~ improvers. If desired, the copolymers may be 5 employed in combination with other addicives, for example, 6 preferably pour point depressants;ashless dispersancs such 7 as the reaction product of polyisobutenyl succinic anhydride 8 with tetraethylene pentamine, detergent ~ype addicives such 9 as calcium nonyl sulfurized phenate and magnesium phenyl 10 sulfonate; zinc antioxidants such as dialkyl dichiophosphate, 11 etc.
12 Mineral oil of lubricating viscosity refers to those 13 materials ob~ained by distilling crude oil under vacuum or 14 otherwise synchesized to provide a lubricating oil suitable 15 for che lubrication of internal combustion engines and hydraulic 16 applications. Although it would be possible ~o classify these 17 mineral oils of lubricating viscosi~y by Sociecy of Automotive 18 Engineers SAE J 300d viscosity classification, however, for 19 the purposes of this disclosure, said mineral oil has a 20 viscosity range: at -18C. to 600 to 9600, preferably from 21 12CG to 240C, centipoises as measured by ASTM Procedure D 26C2;
22 and, a viscosity range at 99C. of 5.7 to 22.7 cencistokes 23 as measured by ASTM Procedure D445.
24 It is a feature of this invention thac significanL
25 improvement in low temperature viscometrlcs may be achieved 26 without undesirable effect on pour point when a pour point 27 depressant is present in a formulated oil. This improvement 28 may be particularly noted when the lubricating composition 29 contains the pour poinc depressant in an amounL of 0.1 wt.%
30 to 1.0 wt.%J preferabLy 0.4 wt.%. Illustrative pour point 31 depressants which may be present in the compositions of -his 32 invention include chlorinaced wax/naphthalenes condensates 33 as described in U.S. 2,174,246, ClO-Cl8 alkyl methacryla,e 34 polymers as described in U.S. 2,G91,627 and 2,100,993, Cl~-C18 35 alkyl acrylates, copolymers of di-n-alkyl fumarace and vinyl 36 acetate as disclosed in U.S. 2,936,300, echylene-vinyl aceta.e

37 copolymers~ and copolymers of styrene and alpha-olefins 1 and copolymers of scyrene and maleic anhydride.
2 In ~he :Eollowing examples, as elsewhere in this 3 specifica~ion~ all par-s are by weighc unless specifically 4 indicaced otherwise.
A series of e~hylene-propylene copolymers were 6 produced with varying ethylene, propylene and/or norborna-7 diene contenc. These copolymers, of which there are five 8 e~amples, are designa~ed here~fter as EPNBD - 1 through 5.
9 These EPNBD copolymers are prepared from eihylene propylene 10 and norbornadiene by varying ~he feed ratio of the three 11 comonomers in ~he polymeri~acion process carried ouc essen~ially 12 as follows (EPNBD-l copolymer is produced under chese spe-13 cific conditions wich all par~s being parts by weight): 3.C
14 par~s of e~nylene, 6.8 parts of propylene, O.GG6 parts of 15 norbornadiene and 45 parts per million of hydrogen was admitted 16 ~o the reactor wich lOC parts of n-hexane, O.Q09 parts of 17 vanadium oxychloride and 0.032 par~s e~hyl aluminum sesquich-18 loride. The catalyst composi.ion was charac,erized by a molar 19 ra~io of Al/V of 4. Residence time ~as abou~ 13 minuces.
20 Polymerization temperacure was 32C. and the pressure was 6G
21 psig. Steam dis~illacion yielded the solvenc-iree echylene 22 copolymer of t~e inven.ion. Copolymers EPNBD 2 to 6 were 23 prepared by appropriate change in ~he feedstock raeio. The 24 specific compositions are set forth hereaf~er:
EPNBD Wt.% Wt.% Wt.%
26 Copolymer Ethylene Propylene Norbornadiene 27 1 45 54O9 ~.1 28 2 43 56.8 0.2 29 3 43 56.~ G.2 4 44 55.6 G.4 31 5 43 56.2 0.8 32 6 43 56.2 G.8 33 An ethylene-propylene copolymer con~aining 46 w;.%
34 e~hylene content was used for compara,ive purposes. This 35 commercially available copolymer was produced generally 36 according to U.S. 3,697,429 and designGted herein as ~PC-l.

~,' 1 EXA~`LE 1 2 In this example, a comparison of oil blend char-3 acteristics of a reference oil containing che copolymers of 4 the invention, i.e. EPNB~ 2-6J is made with samples of said 5 oil containing the echylene-propylene copolymers of the pri.or 6 ar~, i.e. EPC-l. The reference oil is a formulaced cesc oil 7 consisting of solvent neutral oils and a pour depressanc co 8 provide a blend having a viscosity ac 99C. of ca. 6.7 cs.
9 Table II illustrates the effect of both cypes of echyLene 10 copolymers on the blend characceristics of said reference oil 11 when sufficient copolymer is added to provide a 98.9C vis-12 cosity of about 40 cencistokes.

1 TABLE IIl-.

2 Mooney Shear Viscosity Sonic Bulk 3 Oil Copolymer Wt.~ Nor- Visc. Pa~s M~V2-) CCS3-J Shear % Visc.5-) 4 Blend Added bornadiene at 100C T ~ -30C. -18C. Breakdown 100C MPa-s 5 I-A EPNBD-2 0.2 3g.0 2.73 41~2- 2.76 32.2 1.8 6 ~I-B EPNBD-3 0.2 47-5 3~00 56.0 2.63 3~.0 10 7 I-C ~PNBD-4 0.4 51.0 2.94 44.8 ~.69 34.9 10 8 I-D EPNBD-5 0.8 53,0 2.74 36.7 2.74 32.1 10 9 I-E EPNBD-6 0.8 46.0 2.51 31.2 2.69 ~9 ~ 10 10 I-F EPC-l O 41~8 2.87 53.9 2.85 36.6 .1 11 I-K no __ 6.2 __ 19.0 12 copolynler 13 1.) All oils formulated to a viscosity of 12.4 cs at 99C measured in Ubbelohde , 14 viscometer - p~
]5 2.) Couette type viscometer as described by ASTM Committee D-2 RDD VII and VIIC Cw~`
16 operated at ca. 100 Pa shear stress, MiniRotary Viscometer=MRV and Pa~s means ~r 17 Pascal seconds 18 3.) Couette type vlscometer available from Common Instrument Co., P.O. Box 16, State 19 College, PA 16801, operates at ca. .OlMPa CCS=Cold Cranking Simulator; mea-sured by ASTM Test Method D-2607-72 21 4.) ~befbrfe~~after x 100 where ~ is the viscosity measured at 99C in a ~ Ubbelohde viscometer 24 5.) Measured as one-third of the tensile viscosity at a stress of ca. l.~Pa. (G.
Ver Strate, W. Graessley, Rubber Chem. Technol.~ a typical tetrapolymer of 26 U.S. 3,790,480 has a viscosity of 7MPa-s in this test, e.g. Nordel 2522.

- 18 ~

1 The data of Table II show thac it is possible to 2 prepare a series of 2,5-norbornadiene-containing e~hylene 3 terpolymers which exhibi~ the bulk viscosity characteristics 4 of the tetrapolymers of U.S. 3,790,480 in the absence of a s diene of ~he class represented by l,4-hexadiene and furcher-6 more thac these cerpolymers of the invention provide mineral 7 oils of lubricating viscosity with useful and surprising low 8 temperature viscosicy characteristics compared ~o chose 9 provided by ethylene-propylene copolymers. Such low temp-10 erature properties were heretofore obtainable only by in-11 corporating the class of dienes which left residual Imsatur-12 ation in che polymers of the prior arc (both terpolymers 13 and tetrapolymers of ethylene as described in UOS. 3,790,480) 14 or did not provide significant long chain branching as in the 15 ethylene terpolymer containing a Cl C21 alkyl norbornene 16 previously referenced herein.
]7 The copolymers are usefully incorporated into mineral 18 oils of lubricating viscosity in at least viscosicy improving 19 amounts, generally from 0.1 to 15 weight percen~ for lubrlcat-20 ing oil compositions; however~ when said copolymer is placed 21 into commerce as a concencrate in said mineral oil, the 22 copolymer content ranges from 6 to 45 weight percent ( all 23 weight percents are based on the to;al weight of the composi-24 tion or concentrate). Thus in summary, the copolymer (includ-25 ing the oxidized type) of the invention in said mineral oil 26 ranges from 0.1 to 45 wc.% of said copolymer in a major amount 27 of said mineral oil of lubricating viscosity, generally from 28 55 to 99 wt.%.

Claims (13)

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 mineral oil of lubricating viscosity and a viscosity index-improving amount of an oil-soluble, saturated ethylene copolymer having an ethylene content of 26-79 weight percent (35-85 mole percent), and a C3 to C18 higher alpha-olefin and from 0.05 to 3.0 weight percent of 2,5-norbornadiene, said ethylene copolymer having a number average molecular weight (?n) of at least 5,000 and a thickening efficiency in the range of 1.0 to 3 when compared to polyisobutylene having a viscosity average molecular weight (Mv) of 20,000.

2. A lubricating composition according to claim 1 wherein said 2.5-norbornadiene is present in an amount in che range of 0.05 - 1.5 wt.% and is the sole diene present.

3. A lubricating composition according to claim 1 wherein said ethylene copolymer has a thickening efficiency of 1.2 to 2.8 and a (?n) of from about 10,000 to 100,000 and said 2,5-norbornadiene is present in from 0.2 to 0.8 weight percent.

4. A lubricating composition according to claims 1-3 wherein said higher olefin is propylene.

5. A lubricating oil composition according to claim.
1 wherein said copolymer is an oil-soluble oxidatively and mechanically degraded ethylene copolymer having an oxygen con-tent of from about 0.005 to 6 wt.%, based on the total weight of said copolymer.

6. A lubricating composition according to claims 1-3 wherein said ethylene copolymer has an oxygen content of from about 0.05 to 3 weight percent.

7. A lubricating composition according to claims 1-3 which also contains at least a pour depressing amount of a lubricating oil pour depressant.

8. A composition according to claim 5 wherein said degraded cvpolymer is reacted with an amount of amine compound selected from the group consisting of nitrogen com-pounds having the general formulae:

wherein R, R' and R" arc 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 alkyamino C2 to C6 alkylene radicals; Z is O or NG; G is from the group consisting of hydrogen and ?-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.

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 5 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 74 weight percent of C3-C18 alpha-olefins and from about 0.05 to 1.5 weight percent of 2,5-norbornadiene and a thickening efficiency greater than 3Ø

11. A lubricating oil composition comprising a major amount of mineral oil of lubricating viscosity and a viscosity index-improving amount of an oil-soluble, saturated ethylene copolymer having an ethylene content of 26-79 weight percent (35-85 mole percent), and a C3 to C18 higher alpha-olefin and from 0.05 to 3.0 weight percent of 2,5-norbornadiene, said ethylene copolymer having a number average molecular weight (?n) of at least 5,000 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 wherein said copolymer has been oxidatively and mechanically degraded to an oxygen content of from about 0.005 to 6 wt. %, based on the total weight of said copolymer, and reacted with an amount of a polyethylene polyamine containing 2 to 6 nitrogen atoms per molecule to give a product containing about 0.01 to 0.5 wt. % nitrogen.

12. A concentrate comprising a major proportion of mineral oil of lubricating viscosity and from 6 to 45 wt.% of a oil-soluble, saturated ethylene copolymer having an ethylene content of 26-79 weight percent (35-85 mole percent), and a C3 to C18 higher alpha-olefin and from 0.05 to 3.0 weight percent of 2,5-norbornadiene, said ethylene copolymer having a number average molecular weight (?n) of at least 5,000; 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.

13. The concentrate of claim 12 wherein from 0.05 to 1.5 wt.% of 2,5-norbornadiene is present.