CA1077194A

CA1077194A - Additives for lubricants

Info

Publication number: CA1077194A
Application number: CA236,787A
Authority: CA
Inventors: Albert Rossi
Original assignee: Exxon Research and Engineering Co
Current assignee: ExxonMobil Technology and Engineering Co
Priority date: 1974-10-17
Filing date: 1975-10-01
Publication date: 1980-05-06
Also published as: FR2330761B1; FR2330761A1; DE2545958A1; BR7506793A; IT1043435B; GB1526788A; JPS611480B2; BE834566A; NL7512215A; JPS5164510A

Abstract

ABSTRACT OF THE DISCLOSURE

Copolymers of ethylene and a C3 to C18 straight or branched chain alpha-olefin, or terpolymers of ethylene, a C3 to C18 alpha-olefin and a C5 to C12 non-conjugated diolefin, or mixtures thereof and their "polyaminox"
derivatives have been found to have compatibility with alkyl esters and partial alkyl esters-partial amide derivatives of relatively low molecular weight copolymers of an ethylenically ethylenically unsaturated dicarboxylic anhydride, preferably maleic anhydride, and a l-olefin having from 8 to 24 carbon atoms, when formulated together into a lubricant in which the major proportion is a mineral lubricating oil. These copolymer additives act as viscosity index improvers, pour point depressants and sludge inhibitors.
The partial alkyl ester-partial derivatives per se also are useful as diapersantand/or pour point depressant additives for mineral oil lubricants.

Description

~r -- ~077194 1 This invention relates to lubricating oil composi-

2 tions comprising a major proportion of a lubricating oil and

3 a minor proportion of one or more oil-soluble polymers.

4 More particularly, the invention is concerned with one or more polymeric additives which possess pour point depres-6 sant and/or sludge dispersant and viscosity inde~ improving 7 properties when admixed with lubricating oil, unique compati-8 bility, and have good oxidative and thermal stability.
9 The several useful classes of oil-soluble polymer additives are:
11 A. copolymers of ethylene and a C8 to Clg 12 straight or branched chain alpha-olefin, or 13 terpolymers of ethylene, a C3 to Clg alpha-14 olefin and a Cs to C28 non-con~ugated di-olefin, or mixtures thereof;
16 B. "polyaminox" derivatives of oxidized co-17 polymers of ethylene and a C3 to C18 18 straight or branched chain alpha-olefin, 19 or copolymers of ethylene, a C3 to C18 alpha-olefin and one or re Cs to C2g ` 21 diolefins, i.e. the reaction product 22 resulting from aminating said oxidized 23 copolymer with an amine of 2 to 60 car-24 bon atoms and 1 to 12 nitrogen atoms;
C. fully esterified alkyl derivatives of co-26 polymers of maleic anhydride and a l-olefin 27 having from 8 to 24 carbon atoms; and 28 D. alkyl ester-amide derivatives of copolymers 29 of maleic anhydride and a l-olefin having from 8 to 24 carbon atoms.
31 A variety of compositions comprising high-molecu~
32 weight ethylene copolymers, including ~hose which incorp~te - 2 - ~

~)77~94 1 nitrogen, have been described previously as viscosity index 2 (hereafter designated V.I.) improvers for lubricants.
3 U.S. Patents 3,551,336, 3,697,429 and 3,790,480 4 disclose V.I. utility for copolymers of ethylene and one or S more C3 to Clg c~olefins; and copolymers of ethylene, one 6 or more C3 to Clgc~-olefins~ and one or more Cs to C28 non-7 con~ugated diolefins.
8 Oxidation of ethylene copolymers is well known, 9 e.g. U.S. Patent 3,756,924, as is the reaction of oxidized ethylene copolymers with amines, e.g. U.S. Patent 3,785,980.
11 These amine reaction products of the oxidized polymers are 12 identified herein as "polyaminox" products.
13 U.S. Patent 3,316,177 teaches the reaction of poly-14 amine with the reaction product of maleic anhydride and an oxidized interpolymer of ethylene and propylene and their 16 use as sludge dispersants in lubricant and fuel compositions.
17 U.S. Patent 3,687,905 describes the preparation of 18 additives for fuels and lubricants by the reaction of an un-19 saturated acid with an oxidized, degraded interpolymer of ethylene and propylene, followed by reaction with a poly-21 amine.
22 U.S. Patent 3,115,483 describes the preparation of 23 additives for ~et combustion fuels by the reaction of a 1:1 24 molar copolymer of an o~-olefin and maleic acid anhydride with an aliphatic alcohol to produce a mixed mono- and di-26 ester product which was thereafter reacted with a polyamine 27 and salicylaldehyde to produce a Schiff base derivative.
28 U.S. Patent 2,615,845 describes the preparation of 29 high molecular weight copolymers by the reaction of equi-molar proportions of maleic anhydride and straight chainC~-31 olefin having up to 20 carbon atoms and thereafter esterify-32 ing the product with a mixture of saturated straight chain ~ 3 .- :

1 alcohols ranging from 10 to 18 carbon atoms.
2 U.S. 2,543,964 describes lubricating oils improved 3 with respect to the pour point by the addition of copolymers 4 of olefins and esters of unsaturated polybasic acids.
Unfortunately many of these ethylene copolymers 6 and terpolymers useful as V.I. improvers do not exhibit use-7 ful compatibility with many known pour point depressants 8 and/or dispersants so that they can be formulated together 9 as an additive package.
S~ch a unique compatibility has been found to 11 exist by the aforesaid ethylene polymers and an oil-soluble 12 pour point depressant and/or dispersant class of additive 13 materials comprising the reaction product obtained by (1) 14 esterifying a copolymer of a l-olefin, having between about 8 carbon atoms and about 24 carbon atoms per molecule, and 16 maleic acid anhydride with between about 1.2 moles and about 17 1.9 moles per mole of said anhydride of an aliphatic alcohol 18 containing between about 8 and about 18 carbon atoms per 19 lecule to produce a mixed mono- and diester product; (2) reacting said ester product with between about 0.10 mole and 21 about 0.80 m~le of an amine of 2 to 60 carbon atoms and 1 to 22 12 nitrogen atoms.
23 This additive class is uniquely compatible in 24 mineral lubricating oils as an additive package with ethyl-ene copolymers comprising ethylene and a higher C3 to C18 26 alpha olefin. Such ethylene copolymer comprises about 30 to 27 80 wt. ~/O ethylene, about 70 to 20 wt. % of a C3 to Clg alpha 28 olefin and about 0 to 15 wt. % of a Cs to C12 noncon~ugated 29 diolefin, having a number average molecular weight (Rn) in the range of 40,000 to 500,000 with a ratio of the weight 31 average molecular weight (Mw) to the number average lecu-32 lar weight (~w rn) of less than 10, and a crystalline content :

`
, . , - ' 1 of less than 25 percent by weight. The compatibility and 2 utility extends as well to the "polyaminox" derivatives of 3 said ethylene copolymers and mixtures thereof.
4 Further it has been discovered that compatibility is attained in an additive package comprising a ma3Or pro-6 portion of mineral lubricating oil and a minor proportion 7 of a viscosity index improving and a pour point depressing 8 oil-soluble polymer mixture comprising a first copolymer of 9 from about 30 to about 80 wt. ~/O of ethylene, about 70 to about 20 wt. ~b of a C3-Clg alpha olefin and about 0 to 15 11 wt. ~b of a Cs~C12 non-con~ugated diolefin; and, the alkyl 12 ester of a relatively low molecular weight copolymer of 13 maleic anhydride and a l-olefin having from 8 to 24 carbon 14 atoms, said alkyl substituents being a mixture of saturated straight chain alcohols ranging from 6 to 18 carbon atoms.
16 Also, it has been discovered that the polymeric 17 compatibility is attained in an additive package comprising 18 a ma~or proportion of a mineral lubricating oil and a minor 19 proportion of a viscosity index improving and a pour point depressing oil-soluble polymer mixture comprising (A) an 21 aminated oxidized ethylene copolymer obtained by oxidizing 22 a lubricating oil solution of a copolymer comprising ethyl-23 ene and a higher C3 to Clg alpha olefin, at a temperature of 24 80C. to 300-C. to contain 0.01 to 10.0 wt. % oxygen, based on the weight of said oil solution, and then aminating said 26 oxidized oil solution with an amine of 2 to 60 carbon atoms, 27 and 1 to 12 nitrogen atoms; and (B) the alkyl ester of a 28 relatively low lecular weight copolymer of maleic anhyd~de 29 and a l-olefin having from 8 to 24 carbon atoms, said alkyl substituents being from a mixture of saturated straight 31 chain alcohols ranging from 6 to 18 carbon atoms.
32 An additive package for the puxposes of this

- 5 -~077194 1 disclosure is defined as mineral oil containing up to about 2 10 wt. % of the ethylene copolymer or its "polyaminox" deri-3 vative and up to about 3 wt. % of said alkyl or alkyl-amide 4 derivatives of copolymers of maleic anhydride and a l-olefin having from 8 to 24 carbon atoms.

6 Copolymers of ethylene and one or more C3 to C18

7 ~ olefins, and if deslred one or more Cs to C28 diolefins,

8 which may be utilized as the V.I. additive or to prepare the

9 polyaminox derivative, may comprise from 30 to 80 mole per-cent of ethylene; 20 to 70 mole percent of a single C3 to 11 Clg straight or branched chain ~ ~olefin such as propylene,12 l-butene, l-pentene, l-hexene, 5-methyll-pentene, etc., or 13 mixtures thereof; and about 0 to 10 mole percent of one or 14 more Cs to C28 diolefins containing either one or two poly-merizable bonds such as 1,4-hexadiene; 5methyl-2-norbornene;
16 2,4-dimethyl-2,7-octadiene; 1,5~hexadiene; 1,17-octadecadi-17 ene; 5-(5'~hexenyl)-2~norbornene, etc. C3 to C8 ~ olefins 18 are preferred, and propylene is most preferred.
19 Also suitable, are mixtures of copolymers of ethylene with individual ~ ~olefins in the C3 to Clg range, 21 mixtures of copolymers having the same or different 22 olefins and diolefins but differing in monomer content.
23 Particularly suitable, for a V.I. effect are co-24 polymers having a high ethylene content, for example 60 to 80 wt. %, preferably 65 to 75 wt. % ethylene, and which may 26 be 3 to ~5 wt. % e.g., 5 to 10 wt. % crystalline, as general-27 ly they give a greater V.I. effect. These high ethylene 28 polymers can be used per se, or frequently can be blended to 29 advantage with low ethylene conten~ (e.g., 35 to 50 wt. %
ethylene) polymer which in itself gives a good V.I. effect.
31 These high ethylene polymers and said blends are described 32 in U.S. Patents 3,551,336, 3,697,429 and 3,790,480.

~ 6 1(~77194 1 For some applications, particularly when the poly-2 mer is to be the precursor of the "polyaminox" derivative, 3 the copolymers, especially those with at least 3 or 4 wt. %
4 diene are preferred, as the unsaturation in the diene, out-side the backbone of the polymar, is believed to preferen-6 tially oxidize, thereby providing many points for subsequent 7 amination without undue chain breakage and loss of molecular 8 weight and th~ckening efficiency.
9 The catalyst compositions for the preparation of copolymers and terpolymers3 will generally comprise a prin-11 cipal catalyst consisting of a transition metal compound 12 from Groups IVb, Vb and VIb of the Periodic Table of the 13 Elements, particularly compounds of titanium and vanadium, 14 and organometallic reducing compounds from Groups IIa, IIb and IIIa, particularly organoaluminum compounds, which are 16 designated as cocatalysts.
17 Preferred principal catalysts of vanadium are 18 exempli~ied by: VOC13; VOC12 (OBu); VO(AcAc)2; VOC12(AcAc);
19 and V(AcAc)3, whe~e Bu is a n~butyl or isobutyl alXyl radi-cal and (AcAc) is an acetylacetonate.
21 Preferred cocatalysts are exemplified by: Al(Et~;
22 Et2AlCl; EtAlC12; Et3A12C13; and Al(isoBu)3.
23 Representative examples of non-con~ugated dienes 24 useful as monomers for the preparation of suitable terpoly-mers include in addition to those earlier set forth: 1,4 26 pentadiene; 1,5~heptadiene; 1,6~heptadiene; 1,6-octadiene;
27 5-methyl-1,4~hexadiene; 3,7~dimRthyl~1, 6~octadiene; 1,4-28 cyclohexadiene; 1,5~cycloQoctadiene; 4~vinylcyclohexene; 4-29 methylene cyclohexene; 4~ethylidene cyclohexene; 1-allyl-4-isopropylidene cyclohexane, 3-allyL-cyclopentene; 4-allyl-31 cyclopentene; l~isopropenyl-4 (4-butenyl) cyclohexane, 4,4'-32 dicyclopentenyl; 4,4'~dicyclohexenyl; tetrahydroindene;

iO7~1~4 1 methyltetrahydroindene; dicyclopentadiene; bicyclo (2,2,1) 2 hepta-2,5-diene; 5-methylene-2-norbornëne; 5-ethylidene-2-3 norbornene; 5-methylene-6-methyl-2-norbornene; 5-methylene-4 6,6-dimethyl-2~norbornene; 5-propenyl-2-norbornene; 5-iso-propylidene~2-norbornene; 5-(3-cyclopentenyl)-2-norbornene;
6 and 5-cyclohexylidene-2-norbornene; 2,5-norbornadiene; etc.
7 These non-con~ugated dienes having a single poly-8 merizable bond preferably contain 6 to 12 carbon atoms and 9 can be used in an amount of up to about 10 mole percent.
For those applications in which the copolymer as taught in 11 U.S. Patent 3,790,480 are desired, from about 0.1 to 2 12 weight percent of one or more diolefins containing prefer-13 ably 5 to 18 carbon atoms and two polymerizable double bonds 14 can be used for the copolymer.
While these copolymers and terpolymers are essen-16 tially amorphous9 they may contain up to 25 percent by 17 weight of crystalline segments as determined by X-ray or 18 differential scanning calorimetry.
19 Synthesis of the copolymers and terpolymers may be conducted in a slurry process utilizing non~solvents such 21 as methyl chloride or methylene chloride, or in a solution 22 process utilizing moisture and catalyst poison free solvents 23 such as hexane, heptane, and toluene, in batch, staged or 24 continuous reactorsO Polymer made in a solution process is preferred for the "polyaminox" preparation, since the poly-26 mer cement, either before or after deashing, may be mixed 27 or fluxed with the oil to form a solution.
28 Solvent, monomers, principal catalyst and cocata-29 lyst are fed to the reactor, supplied with means for with-drawal of the heat of reaction, and maintained under con-31 trolled agitation for a time, temperature, concentrations 32 and pressure sufficient to complete the reaction or ensure ~ 8 -.

107719~

1 a steady~state equilibrium.
2 Suitable times of reaction will generally be in 3 the range of from about 1 to 300 minutes, temperature will 4 usually be in the range of 0C. to lOO~C. and pressures fsom atmospheric to 160 psig may be employed. Monomers fed 6 to the reactor per 100 parts by weight of solvent may be in 7 the range of: ethylene, 2 to 20 parts by weight; C3 to Clg 8 ~ -olefin, 4 to 20 parts by weight; and when used to pre-9 pare a terpolymer, non-con~ugated diolefin, 0.1 to 10 parts by weight.
11 Principal catalyst, VOC13 for example, prediluted 12 with solvent, can be fed to the reactor so as to provide a 13 concentration in the range of 0.1 to 5.0 millimoles per 14 liter. Cocatalyst, for example Et3A12C13, also prediluted if desired, can be fed to the reactor at the same time in an 16 amount equal to from about 2.0 to 20 les of cocatalyst per 17 mole of principal catalyst.
18 Suitable copolymers have number average molecular 19 weights (Mn) in the range of about 500 to 500,000. In general, polymers having a narrow range of molecular weight, 21 as determined by the ratio of weight average molecular 22 weight ~M-w) to (Rn) are preferred. Polymers having a Mw rn 23 of less than 10, preferably less than 7, and most prefer-24 ably 4 or less, are most desirable. Polymers in this range may be obtained by selection of synthesis conditions and 26 addition of hydrogen in the range of 10 to 10,000 ppm of the 27 ethylene feed, and by post synthesis treatment such as ex-28 trusion at elevated temperatures and under high shear 29 through small orifices, or by fractional precipitation from solution.
31 The properties of a number of useful random poly-32 mers and random terpolymers are summarized in Table I, which 33 follows:

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1~)77194 1 The above-described ethylene copolymers can be 2 oxidized and thereafter reacted with amines to produce the 3 "polyaminox" derivatives.
4 Oxidation of ethylene copoly~ers and reactions with nitrogen containing compounds are both well known.
6 Oxidation pr~or to reaction can be carried out by numerous 7 processes including mechanical degradation, heating in air 8 or hydroperoxidation.
9 Particularly useful are ethylene copolymers oxi-dized in mineral oil and subsequently reacted with amines.
11 In this process a wide variety of oils may be used for the 12 oxidation. The oils may range in viscosity from about 5 to 13 1000 SUS @100F., most preferably 80 to 200 SUS @100F.
14 They may be straight-run distillates in the lubricant range, e.g., bolling above 600F., or further refined. Also suit-16 able are synthetic hydrocarbon oils in the lubricant range 17 made by polymerization, oligomerization, alkylation of aro-18 matics with olefins, and the like. Preferred, because they 19 give less undesirable by-products during oxidation, e.g., color bodies, are oils having a sulfur content of less than 21 0.25 weight percent, a nitrogen content of less than 25 22 micrograms per ml., and an aromatic content of less than 30 23 weight percent.
24 Oxidation of the copolymers and terpolymers dis-solved in the oil is conveniently carried out, either in 26 batches or continuously, in a stirred reactor with air, or 27 air prediluted with an inert gas such as nitrogen or carbon 28 dioxide so as to minimize explosion hazards. The air, or 29 diluted air, may be introduced into the oil-polymer solution in a finely divided state at a temperature in the range of 31 about 80C. to 300C., preferably 100C. to 230C. with 32 rapid agitation of the reactor contents.

:
, 1077~ 94 1 In general, in the range of 0.5 to 90, e.g., 4 to 2 60 weigh~ percent of the oil-polymer solution will be poly-3 mer. Usually, about 20 to 60 weight percent of the solution 4 will be polymer when the polymer is o~ low mol. wt., e.g., with a number average molecular weight (Mn) less than 6 20,000. For polymers with Mn equal to or greater than 7 20,000, the preferred concentrations are in the rànge of 4 8 to 20 weight percent polymer, based on the total weight of 9 the oil-polymer solution.
Oxidation of the oil-polymer solution is conducted 11 for a time sufficient to i~part to the solution a combined 12 oxygen content of about 0.01 to 10.0, e~g., 0.1 to 8, pre-13 ferably 0.1 to 5.0 weight percent, depending on the compo-14 sition of the oil, the polymer and the concentration of polymer in solution.
16 As used herein, such terms as "oxidized", or "oxi-17 dized oil polymer solution" etc. indicates that alr or oxy-18 gen containing gas is used for the oxidation, and precludes 19 the use of other oxidative reagents such as ozone.
Useful amine compounds for condensation with the 21 oxidized polymer-oil solutions to form the polyaminox prod-22 ucts of this in~ention include amines of about 2 to 60, e.g., 23 3. to 20, total carbon atoms and about 1 to 12, e.g., 1 to 24 6 nitrogen atoms in the molecule, which amines may be hydro-carbyl amines or may include other groups, e.g., 1 to 4 26 hydroxy groups, alkoxy groups, amide groups, imidazoline 27 groups and the like.
28 Preferred amines are aliphatic, saturated amines, 29 and include those of the general formulae:
3l R-N-R" and R-N-(cH2)s-[-N-(cH2)s-]tN-R
32 R' R' R' R' 33 wherein R, R' and R" are independently selected from the 1C~77~94 1 group consisting of hydrogen; Cl to C12 straight or branched 2 chain alkyl radicals; Cl to C12 alkoxy substituted C2 to C6 3 alkylene radicals; C2 to C12 hydroxy or amino alkylene 4 radicals; and Cl to C12 alkylamino substituted C2 to C6 alkylene radicals; s is 2 to 6, preferably 2 to 4; and t is 6 0 to 10, preferably 2 to 6.
7 Examples of suitable amine compounds represented 8 by the above include: n~octyl amine; n-dodecyl amine; di-9 (2-ethylhexyl) amine; 1,3-diaminoethane; 1,3-diaminopropane;
1,4-diaminobutane; 1,6-diaminohexane; diethylene triamine;
11 triethylene tetramine; tetraethylene pentamine; 1,2-propyl-12 ene diamine; di-(1,2-propylene) triamine; di-(1,3-propylene) 13 triamine; N,N-dimethyl-1,3-diaminopropane; ~,N-di-(2-amino-14 ethyl) ethylene diamine; N,N-di-(2-hydroxyethyl)-1,3-propyl-ene diamine; 3-dodecyl oxy propylamine; Ndodecyl-1,3-pro-16 pane diamine; diethanol amine; morpholine; tris-hydroxy-17 methyl aminomethane (THAM); diisopropanol amine; etc.
18 Still other useful amine compounds include: ali-19 cyclic diamines such as 1,4~di-(aminomethyl) cyclohexane and heterocyclic nitrogen compounds such as imidazolines and N-21 aminoalkyl piperazines such as 2~pentadecyl imidazoline; N-22 (2-aminoethyl) piperazine; N~(3~aminopropyl) piperazine;
23 and N,N'-di(2-aminoethyl) piperazine.
24 Other alkylene amino compounds that can be used include dialkylamino alkyl amines, such as dimethylamino 26 ethyl amine, dimethylamino propyl amine, methylpropylamino 27 amyl amine, etc.
28 Comm~rcial mixtures of amine compounds may advan-29 tageously be used for the preparation of the polyaminox com-positions of this invention. For example, one process for 31 preparing alkylene amines involves the reaction of an alkyl-32 ene dihalide (such as ethylene dichloride or propylene di-14 ~

, 1 chloride) with ammonia, which results in a complex mixture 2 of alkylene amines wherein pairs of nitxogens are ~oined by 3 alkylene groups, forming such compounds as diethylene tri-4 amine, triethylene tetramine, tetraethylene pentamine and isomeric piperazines. Low cost poly(ethylene amines) com-6 pounds having a composition approximating tetraethylene rna. ~s 7 pentamine are available commercially under the trade namcs 8 Polyamine H, Polyamine 400 (PA-400) and Polyamine 500 (PA-9 500). Similar materials may be made by the polymerization of aziridine, 2-methylaziridine and azetidine.
11 The more important alkylene polyamine or aliphatic 12 polyamine compound, used in this invention, can be broadly 13 characterized as an alkylene amino compound containing from 14 2 to 12 nitrogen atoms wherein pairs of nitrogen atoms are ~oined by alkylene groups of from 2 to 4 carbon atoms.
16 Reaction of the æmine compound with the aforesaid 17 preferred oxidized polymer-oil solution takes place readily 18 at a temperature in the range of about 40C. to 300C., 19 preferably at a temperature in the range of 100C. to 200C.
Accordingly, after the oxidation of the oil-polymer solution 21 has reached the desired level, the required amount of amine 22 compound, usually in the range of about 0.1 to 4.0 wt. %
23 based on the weight of the polymer, may be added with mixing 24 and the reaction mixture maintained at the required tempera-ture while removing any water that forms. The time for com- -26 pletion of the reaction of the amine compound with the oxi-27 dized oil-polymer solution is in the order of about 15 min-28 utes to ten hours depending on temperature, degree of mix~
29 ing and reactivity of the amine rompound. The final amina-ted product will usually contain in the range of about 0.03 31 to 5, e.g. 0.1 to 3.0 wt. % nitrogen, based on the total 32 weight of the aminated polymer~in~oil solution.

:

~077~94 1 The copolymers of maleic anhydride and l-olefin 2 which are useful for this invention, have number average 3 molecular welghts in the range of 1000 to 30,000. These co-4 polymers are readily polymerized by conventional techniques such as by a free radical polymerization promoter. The 6 alkyl ester is produced by esterification with an alcohol 7 after polymerization.
8 The copolymers of maleic anhydride and l-olefin 9 used for preparation of the esters and ester-amides were earlier stated to be useful when having a Mn in the range of 11 1,000 to 30,000. Such a Rn range also substantially covers 12 the useful range of the ester and ester-amide derivatives.
13 The preferred ester and ester~amide derivatives have a Mn 14 ranging 1500 to 20,000 and optimally, the Rn ranges from about 2,000 to 15,000.
16 Instead of maleic anhydride, one may also use 17 other ethylenically unsaturated dicarboxylic acid anhydrides 18 including itaconic anhydride and derivatives of maleic an-19 hydride. Maleic anhydride is preferred, however.
Maleic anhydride derivatives for the purpose of 21 this disclosure include those of the generic formula:
22 Rl R2 26 0 ~ C C = 0 27 \ X /
28 wherein Rl and R2 are hydrogen or a halogen and X is oxygen, 29 NH, or NR3, wherein R3 is an alkyl group, preferably a Cl to C40 alkyl. Suitable examples of such derivatives include 31 itaconic anhydride, N-ethyl maleimide, N-hexyl maleimide, 32 N-dodecyl maleimide, N~tetradecyl maleimide, ~-eicosyl male-33 imide, N-tetracosyl maleimide, chloromaleic anhydride and 34 dichloro maleic anhydrideO

1~7 719 4 1 The maleic anhydride is reacted with an aliphatic 2 l-olefin containing from 8 to 24 carbon atoms per molecule, 3 i.e. octene-l, nonene-l, decene-l, etc. through tetracosene-4 1. All are "straight chain" l olefins; but also useful are branched l-olefins as for example 2-methyl heptene-l; 2-6 methyl hexadecene-l, and 2,~,4-trimethyl pentene-l. Mix-7 tures of these l-olefins are suitable.
8 The reaction between the maleic anhydride and 1-9 olefin, usually in about equal molar proportions, can con~
veniently be carried ou~ by mixing the l~olefin and maleic 11 anhydride in about equimolar amounts, and heating the mix-12 ture ~o a temperature of 120 to 300Fo ~ preferably from 13 175 to 250F. A free radical polymerization promoter such 14 as azo-isobutyl nitrile, benzoyl peroxide, tobutyl perbenzo-ate or di-t-butyl peroxide is normally used. Polymerization 16 time is normally 3 to 8 hours. The addition product thus 17 prepared is reacted with about 2.0 moles of an alcohol or 18 mixture of alcohols, per mole of maleic anhydride. Such 19 alcohols are straight chained or contain one methyl or ethyl branch on the second carbon, and are ~aturated aliphatics 21 having from 6 to 18 carbon stoms~ The low lecular weight 22 polymer may be isolated by precipitation in methanol or iso-23 propanol, filtering and vacuum drying in an oven. Further 24 details are set forth in U.S. Patent 3,706,704.
Preferred are those alcohols having from 10 to 18 26 carbon atoms which thus include decanol, dodecanol, tetra-27 decanol, hexadecanol, octadecanol, 2-methyl-1-dodecanol, 28 etc.
: 29 The alkyl ester~amide derivatives are additives which are highly useful as pour point depressants and¦or 31 dispersants, alone as well as in combination with the pre-32 viously mentioned ethylene copolymers and terpolymers and/or :

~077~94 1 the "pol~aminox" products.
2 The alkyl ester amide derivatives are prepared in 3 accordance with the pr~cedures used to prepare the alkyl 4 esters except that the precursor copolymer of maleic anhy-dride snd l-olefin is not fully esterified. Rather the 6 molar amount of the alcohol is limited to from 1.2 mole to 7 1.9 mole of alcohol per mole of maleic anhydride. The alkyl 8 ester is thereafter reacted with sufficient amine to amin-9 ate the balance of ~he carboxyl groups of the copolymer;
i.e. from 0.1 to 0.8 mole of amine is reacted with the re-11 maining acidic part of the copolymer.
12 In general, useful amines include amines of about 13 2 to 60 e.g. 3 to 20, total carbon atoms and about 1 to 12, 14 e.g. l to 6 nitrogens, which amines may be hydrocarbyl amines or may include other groups, e.g. hydroxy groups, 16 amide groups, imidazoline groups, etc. These useful amines 17 have been earlier set forth as useful for the amination of 18 the oxidized ethylene copolymers and terpolymers. Thus the 19 useful amines can be simple amines such as dodecylamine, di-(2-ethylhexyl) amine, and ethylene diamine; and polyamines 21 including ethylenediamine, hydrazine, diethylenetriamine, 22 tetraethylenepentamine, di(methylethylene) triamine, N-(2-23 hydroxy-ethyl) 1,2-ethanediamine, n-phenyl-ethylene diamine, 24 N-cyclohexyl-N'(2-amino ethyl)-1,2-ethane-diamine, pipera-zines, etc.
26 The ethylene copolymers and terpolymers and their 27 polyaminox derivatives can be dissolved in oil for ease in 28 dispensing. This forms a concentrate which contains from 5 29 to 25 wt. % polymer with about 7 wt. % being preferred.
The ester or ester/amide polymers are dissolved in 31 oil in an amount of from 20 to 60 wt. % with about S0 wt. %
32 being preferred, to provide the concentrate.

~077194 1 These concentrates are mixed together to provide 2 the additive package of the invention~ In general, 90 to 3 98 parts by weight of the concentrate of the ethylene co-4 polymer or its "polyaminox" derivative is blended with 10 to 2 parts by weight of the concentrate of the ester or 6 the amide/ester at 130F. for 1 hour. In the preferred 7 ratios mentioned above, this provides a concentrate in 8 which the V.I. improver and alkyl ester (includes ester-9 amide) are present in ranges of about 6.3 to 6.9 wt. ~/O and 1 to 5 wt. %, respectively. The weight percents as used 11 herein are based on the total weight of the lubricant, 12 package, concentrate, etc. unless otherwise noted.
13 The diluent oils which can be used in these con-14 centrates include those mineral oils utilized as solvents for the polymer-oil solutions to be oxidized prior to 16 amination in preparation of the "polyaminox" derivatives.
17 Also suitable are lubricating oils derived from shale oil, 18 coal and tar sand and mixtures of the foregoing.
19 The additive packages can be incorporated in lub-ricating oil compositions, e.g., automotive crankcase lu~ri-21 cating oils, automatic transmission fluid (ATF) compositions, 22 etc., in concentrations within the range of about 7 to 20 23 wt. % of the total composition. Thus in said lubricating 24 oil compositions the V.I. improvers are preferably pxesent in an a unt ranging from about 0.4 to 1.4 wt. % and the 26 dispersant esters (includes ester-amide) are present in an 27 amount ranging from about 0.07 to 1.0 wt. %. Lubricating 28 oils of said lubricating oil compositions include not only 29 mineral oils but also synthetic oils such as alkyl esters of dibasic ac~ds, complex esters comprising dibasic acids, 31 polyglycols and alcohols~ polyglycols and carboxylic acid 32 esters of polyglycols~

~ 19 - ~

~077~94 1 The following tests were used to evaluate compati-2 bility and utility of these additives.
3 Compatibility Test 4 Two additive concentrates are mixed together with heating, e.g. up to about 150F., and agitation until ap-6 psrently homogeneous upon visual examination. The test mix-7 ture is stored at room temperature and at elevated tempera-8 tures and periodically observed to detect precipitation, 9 flocculation or phase separation. If none of these occur within the test period the mixture is considered compa~ible.
11 A further test is to use this apparently compat~le 12 mixture to formulate and evaluate a multi-graded oil, e.g.
13 lOW-30.
14 Pour Point Test The pour test for lubricating oils as set forth 16 by ASTM D-86 determines the lowest temperature at which the 17 oil will pour under conditions specified thereby.
18 Slud~e Inhibition Bench (SIB) Test 19 The dispersant activity of the additives was de-termined in a SIB test as follows:
21 A used, dispersant-free, automotive mineral lubri-22 cating oil containing a V.I. i~prover, a pour point depres-23 sant, and a zinc dialkyldithiophosphate antiwear agent, 24 which oil had an original viscosity of 325 SUS at 100F., was obtained by pooling the oil drained from the crankcase 26 of a fleet of taxicabs operating in New York City. The 27 used oil was centrifuged in heavy-walled 50 ml. tubes at 28 about 16,000 RPM for one-half hour and the clear supernatant 29 oil, free of sludge but containing dissolved therein sludge precursors, was decanted from the sludge and used in the 5IB
31 test.
32 In conducting the test 0.5 wt. Z of the additive 1C~77~94 1 was dissolved into the used, centrifuged oil and added to 2 preweighed centrifuge tubesO The tubes were stored in a 3 heating block at 280Fo for 16 hours, along with tubes con-4 taining blanks, l.e., containing only the centrifuged used oil to which no dispersant additive was added. After heat-6 ing for 16 hours, the tubes were centri~uged at 16,000 RPM
7 for one-half hour and the supernatant oil decanted and dis-8 carded. The tubes were inverted and allowed to drain in a 9 rack for not more than 15 minutes, after which the walls of each tube were rinsed with 25 ml. of pentane, taking care 11 not to disturb the sludge compacted in the tip of each tube.
12 A second 25 ml. portion of pentane was added to each tube 13 and the sludge dispersed and any occluded oil dissolved by 14 gentle shaking. The tubes were then centrifuged in a refri-gera~ed centrifuge at 16,000 RPM for one-half hour, the pen-16 tane decanted and discarded. After rinsing the exterior of 17 each tube with acetone, the tubes and contents were allowed 18 to dry at room temperature for one hour and weighed, the 19 weight of sludge in each tube being obtained by difference.
The effectiveness of the dispersant is expressed as the 21 weight (in milligrams) of sludge in each tube as compared to 22 the weight of sludge found in the blanks, which had no 23 dispersant.
24 The oils were formulated with sufficient amounts of additives so that the viscometric requirements of SAE
26 lOW-30 and lOW~40 were met.

28 A typical laboratory preparation of the alkyl 29 ester of maleic anhydride~l-olefin copolymer designated Polymer C is as fol~ows:
31 To a 500 mlO 4-necked flask having a stirrer, 32 thermometer, and charging funnel were added; 80 grams of 21 ~

~077194 xylene, 24.5 grams (0.25 mole) of maleic anhydride and 76 2 grams ~0.30 moles) of a Clg olein mixture. The reactants 3 were heated to 145C. and 1.1 gram di-t-butyl peroxide was 4 added. The reaction mixture was cooled to ambient temE~era-5 ture and then poured slowly into 2 liters of chilled isopro-6 panol. The precipitated copolymer was filtered and dried in 7 a vacuum oven overnight at 30C. The copolymer yield was 8 88% of theoretical and upon analysis gave 75.13 wt. % car-9 bon and 10.83 wt. % hydrogen. Its molecular weight Mn was

10 determined to be about 2800 by vapor phase osmometry.

11 To 35 grams (0.1 mole) of the isolated copolymer,

12 41.4 grams (0.2 mole) of C12~18 commercial alkanol, 30 ml.

13 of toluene and 0.5 grams of p-toluene sulfonic acid were

14 added. The mixture was heated to 130~150C. for 12 hours

15 to remove the water formed by esterification. A sample of

16 the reaction product was dialyzed for 3 hours with boiling

17 toluene in a Soxhlet extraction device, using a semi-

18 perme~ble rubber membrane to remove low molecular weight

19 components. The residue, representing esterified copolymer,

20 was obtained in 90 wt. ~/1, yield and had a number average

21 molecular weight of about 5000, a carbon content of 76.7 wt.

22 %, and a hydrogen content of 11.7 wt. %.

23 The Clg l-olefin used was about 93% total mono-

24 olefin and 7% paraffin; about 80% of this monoolefin was

25 the alpha type and about 14% was the vinylic type.

26 The commercial C12_1g al~anol that was used was a

27 mixture of synthetic alcohols, about 2 wt. % of Clo alcohol,

28 about 56 wt. % C12 alcohol, about 21 wt. % of C14 alcohol,

29 about 10 wt. % of Cl6 alcohol and about 11 wt. % of C18

30 alcohol.

31 EXA~D?LE 2

32 The prDcedure of Example 1 was used to prepare 1~7 71 9 ~

1 another alkyl ester of the maleic anhydride l~olefin copoly-2 mer. The commercial C12O18 alkanol was replaced by a mix-3 ture of C6~1g straight chain alcohols derived from fatty 4 acids and containing about 3 wt. % C6 alcohol, 10 wt. % C8 alcohol, 8 wt. % Clo alcohol, 45 wt. % C12 alcohol, 18 wt.
6 % Cl~ alcohol, 7 wt. % C16 alcohol and 10 wt. % Clg alcohol.

8 The following preparations exemplify the prepara-9 tion of partial ester-partial amide derivatives of a co-polymer of maleic anhydride and l-olefin. The procedure of 11 Example 1 was followed except that the C12~18 alcohol mix-12 ture was reacted in an amount of 33 grams (1.6 mole/mole 13 anhydride) and the resulting product was not isolated but 14 thereafter aminated as follows:
To the above mixture at 280~F., 3.7 gms. (0.4 16 mole) of Polyamine 400 was added. The mixture was then 17 stripped with nitrogen for 2 hours while at 280F. The 18 final product, upon dialysis, has a number average molecular 19 weight of 13,400, a nitrogen content of 2.4 wt. %, a carbon contentof 74.9 wt. %, and a hydrogen content of 10.8 wt. %.

22 The procedure of Example 3 was followed except 23 that the alcohol addition was increased to 35 grams (1.7 24 mole/mole of maleic anhydride) and the Polyamine 400 addi-tion was reduced to 207 grams (0.3 mole/mole of maleic anhy-26 dride).
27 The final product, upon dialysis, has a number 28 average molecular weight of 10,200, a nitrogen content of 29 1.1 wt. %, a carbon content of 75.6 wt. % and a hydrogen content of 11.8 wt~ %.

32 The procedure of Example 3 was followed except .

-~07ql94 1 that the alcohol addition was increased to 37 grams (1.8 2 mole/mole of maleic anhydride) and ~he Polyamine 400 addit~on 3 was decreased to 1.9 grams (0.2 mole/mole of maleic anhy-4 dride).
The final product, upon dialysis, has an average 6 number molecular weight of 11,400, a nitrogen content of 7 1.8 weight %, carbon content of 75.0 wt. % and a hydrogen 8 content of 11.5 wt. %.

The procedure of Example 1 was followed except 11 that the octadecene (Clg alphaolefin mixture) was replaced 12 by 0.30 moles of octene-l.

14 The procedure of Example 1 was followed except that the octadecene (Clg alpha-olefin mixture) was replaced 16 by 0.30 moles of 2,4,4~trimethyl pentene~lO
17 The products of Examples 1-7 were tested in Sol-18 vent 150 Neutral, which is a neutral solvent-extracted 19 mineral lubricating oil having a viscosity of about 150 SUS
at 100F. and a pour point of 0F. and compared with two 21 commercially available additiYes and a control with the fol-22 lowing results.

24 Pour Test S 15QN _ SIB Test V/~I our Po nt o 26 Additive Treat Blend. F. VtvAI* Treat M~. Slud~e 27 Prod.Ex. 1 0.1 -20 0.5 22 28 Prod.Ex. 2 0.1 -20 0.5 29 Prod.Ex. 3 0.1 -25 0.5 8 Prod.Ex. 4 0.1 -20 0.5 12 31 Prod.Ex. 5 0.1 -20 0.5 15 32 Prod.Ex. 6 0.1 -25 - 18

33 Prod.Ex. 7 0.1 -20 ~.

i~77194 1 TABLE II (continued) 2 Comm.Lube oil 3 pour depressant 0.1 -20 - -4 Comm.ashless dis-5 persant - - 0.5 8 6 None - 0 - 25 7 * % AI is ~he weight percent active ingredient.
8 These data demonstrate that some of the polymers 9 (see Ex. 3, 4, S, and 6) are not only pour point depres-10 sants but also dispersants. Also several of these polymers 11 (see Examples 1 and 2) are pour point depressants as would 12 be expected from the teachings of U.S. Patent 2,542,542;
13 however, this patent does not disclose Example 7.

Crankcase oils were formulated with base stocks 16 obtained from seven different refineries (base stocks A
17 through G). These base stocks have viscosities at 210F.
18 of about 5 to 5.5 cs, and natural pour points of about 0 to 19 +lSF. To these oils sufficient amounts of Polymer A' or 20 Polymer B' and Polymer Product of Example 1 or Polymer Pro-21 duct of Example 3 were added so that they meet the kinematic 22 viscosity requirements for SAE Graded oils of lOW/30 or lOW/
23 40 and have pour points of 15F. or below; the characteris-24 tics of these blends are shown in Table III.
2~ Polymer A' is a blend of equal amounts of ethyle 26 propylene copolymer (about 67 wt. % ethylene~ having a ~n 27 of about 40,0Q0 and an ethylene~propylene copolymer (about 28 46 wt. % ethylene~ having a Mn of about 559000; both of said 29 copolymers being prepared by a Ziegler-Natta synthesis in 30 the presence of hydrogen as a moderator.
31 Polymer B' is obtained by oxidation of a mixture 3~ of 4~/O by weight of said ethylene~propylene copolymer (about 33 67 wt. % ethylene), having a Mn of about 40,000, and 60% by

34 weight of said ethylene-propylene copolymer (about 46 wt. %

1~77~g4 1 ethylene), having a Mn of about 55,000, to a thickening ef-2 ficiency of 1.4 and amidation of 13.6 wt. % of said oxidized 3 copolymer blend in mineral oil at 150C. for 5 hours with 4 diethylenetriamine to a nitrogen content of about 0.04 wt.
% after heavy nitrogen sparging to remove unreacted amine.
6 Substantially all of the amidation occurs on the oxidized 7 ethylene-propylene copolymers.

pour 10 SAE VI Polymer Pour Point,*
11 Basestocks Grade Improver Depressant F.
12 A lOW/40 Polymer A' Prod. Ex. 1 -15 13 B lOW/40 Polymer A' Prod. Ex. 1 -25 14 C lOW/40 Polymer A' Prod. Ex. 1 -35 D lOW/30 Polymer A' Prod. Ex. 1 -35 16 E lOW/40 Polymer A' Prod. Ex. 1 -20 17 F lOW/40 Polymer A' Prod. Ex. 1 -25 18 G lOW/40 Polymer A' Prod. Ex. 1 -20 19 G lOW/40 Polymer A' Prod. Ex. 3 -20 G lOW/40 Polymer B' Prod. Ex. 3 -20 21 *Determined by ASTM D-97 23 Compatibility of polymer blends useful as additive 24 packages of the invention, 1.~. blends of ethylene copoly-mers and terpolymers (Polymers A') and "polyaminox" deriva-26 tives (Polymers B') with the alkyl esters and amide-ester 27 derivatives of the copolymer of maleic anhydride and l-ole-28 fin, are shown in the following Table IV:

Wt. % Blend of Polymer Concentrates* Stora~e Stability Days 32 A' B' Prod.Ex.l Prod.Ex.3 75F. 150F. 180F.

34 96 - - 4 >50 ~ 14 -~oms~
1 - 96 4 - > 50 > 14 2 - 96 - 4 ~50 > 14 3 *The concentrates for Polymers A' and B' were about 7 wt. %
4 and for the Polymer Products of Ex. 1 and 3 were about 50 wt. %, respectively.
6 After the storage stability tests, the above addi-7 tive mixtures were found compatible.

:' ,; , .. .
. .

Claims

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

1. A lubricating composition comprising a major amount of a lubricating oil and an amount sufficient to improve the low temper-ature properties of said oil of a viscosity improver comprising co-polymers of ethylene and a C3 to C18 straight or branched chain .alpha.-olefin, or terpolymers of ehtylene, a C3 to C18 .alpha.-olefin and a C5 to C12 nonconjugated diolefin, or mixtures thereof and a sludge dis-persing amount of the alkyl ester of a relatively low molecular weight copolymer of ethylenically unsaturated dicarboxylic anhydride and a l-olefin having from 8 to 24 carbon atoms, said alkyl substi-tuent being saturated straight hydrocarbon chains ranging from 6 to 18 carbon atoms.

2. The composition of claim 1 wherein said viscosity im-prover is present in a total of 6.3 to 6.9 wt.% and said alkyl ester is present in a total of 1 to 5 wt.%.

3. The composition of claim 1 wherein said viscosity im-prover is present in a total of 0.4 to 1.4 wt.% and said alkyl ester is present in a total of 0.07 to 1.0 wt.% and said anhydride is maleic.

4. The composition of claim 1 wherein said viscosity im-prover comprises an aminated oxidized ethylene copolymer obtained by oxidizing a lubricating oil solution of a copolymer of ethylene and a C3 to C18 straight or branched chain .alpha.-olefin, or terpolymers of ethylene, a C3 to C18 .alpha.-olefin and a C5 to C12 nonconjugated diole-fin, or mixtures thereof, at a temperature of 80°C. to 300°C. and for a time sufficient to impart to said solution a combined oxygen con-tent of 0.01 to 10.0 wt.% oxygen, based on the weight of said oil solution, and then aminating said oxidized oil solution with an amine of 2 to 60 carbon atoms, and 1 to 12 nitrogen atoms.

5. The composition according to claim 1 or 4 wherein said 1-olefin is octadecene-1 and said alkyl substituent is derived from a mixture of C12-C18 straight-chain alcohols.

6. The composition according to claim 1 wherein said alkyl ester is obtained by partially esterifying a copolymer of a 1-olefin having between about 8 carbon atoms and about 24 carbon atoms per molecule, and an ethylenically unsaturated dicarboxylic anhydride with an aliphatic alcohol containing between about 10 and about 18 carbon atoms per molecule to produce a mixed mono- and diester pro-duct; and reacting said ester product with an amine of 2 to 60 carbon atoms and 1 to 12 nitrogen atoms.

7. The composition according to claims 1 or 4 wherein said alkyl ester is derived from maleic anhydride and a branched 1-olefin of the class consisting of 2-methyl heptene-1, 2-methyl hexadecene-1, 2,4,4-trimethyl pentene, and mixtures thereof.

8. The composition according to claim 6 wherein said amine is a polyethylene polyamine.

9. The composition according to claim 6 wherein said amine is tetraethylene pentamine.