CA1168649A

CA1168649A - Lubricating compositions

Info

Publication number: CA1168649A
Application number: CA000398767A
Authority: CA
Inventors: Robert E. Malec
Original assignee: Edwin Cooper Inc
Current assignee: Edwin Cooper Inc
Priority date: 1981-03-23
Filing date: 1982-03-18
Publication date: 1984-06-05
Also published as: JPS57202388A; JPS6024156B2; DE3267749D1; EP0061346A2; EP0061346B1; EP0061346A3

Abstract

Abstract of the Disclosure Lubricating oil dispersancy is synergistically improved by use of a combination of (a) a boronated hydrocarbon-substituted succinic amide/
imide/ester of an oxyalkalated amine and (b) a Mannich condensation product of a hydrocarbon-substituted phenol, formaldehyde, and amine, and optionally, a fatty acid and or a boronating agent.

Description

1 ~ 6 ~

Dispersants are used in engine lubricating oil to pre~ent sludge formation and to inhlbit varnish on hot engine surfaces such as pistons. Hydrocarbon-substitut~d succinimides are qui~e effective in such use (U.S. 3,172,892).
Likewise, succinimides of hydroxyalkyl substituted amines have been shown to be e~fective ~U.S. 3,219,666~. Borona-tion of such succinimides.has also been practiced (U.S.
Patents 3,322,670; 3,254,G25 and 3,087,936~ Boronating processes are also taught in U.S. Patents 3,082,955 and 3,950,341).
Mannich dispersants made from hydrocarbon-substituted phenols formaldehyde and amines are also known (U.S. Patents 3,413,347; 3,725,277; 3,368,972 and 3,798,165j.
Boron-modified Mannich dispersants are described in U.S.
Patents 3,697,574; 3,703,536; 3,704,308; 3,751,365 and 3,756,953. Fatty acid modified Mannich dispersants are ~:
described in U.S. Patents 3,798,247 and 3,8039039. Further represen~ative patents induce the following: U.S. Patents, 3,442,808; 3,448,047; 3,539,633; 3,634,515; 3,7369357;
3,793,202; 4,142,980, 4,006,089; 3,980,569; 4,071,3~7;
4,070,402; 3,985,802; 4,161,475; 4,170,562; 4,016,092; and British Patent 1,362,013.
According to the present invention, improved lubricating oil compositions are provided which contain a synergis~i~c combination of (a) a boronated hydrocarbon-substituted succinic amide/imide/ester of an oxyalkylated amine and ~b~. a Mannich condensation product of a hydrocarbon-su~stituted pheno, formaldehyde and an amine and optionally a boronating agent and~or ~atty acid. In a standard ASTM
Sequence YD engine test, the synergistic combination gives a much. better piston varnish. rating then either individual component used at th.e same or even greater total concentra-tion.
A preferred embodiment of the invention is a lubricating oil composition comprising a major amount of an oi-l lubri;cating yiscos.i:ty containing a minor dispersant amount of a synergistic combination of dispersants, said combination comprising mab/~ V

I .t6~..1g (A) a boronated succinimide dispersant having in its structure at least one aliphatic hydrocarbon-substi-tuted succinoyl group R -CH~
CH -C~

wherein R is an aliphatic hydrocarbon group having a molecular weight of 700-50,000, said succinoyl group being bonded to a nitrogen atom of an oxyalkylated amine to form an amide or imide or to an oxygen atom of said oxyalkylated amine to form an ester or to both nitrogen and oxygen atoms of sai~d oxyalkylated amine to form a mi~xture containing amide, imi~de and ester groups, said succlnimide dispers~ant being further characterized by containing 0.001-2.5 weight percent boron, and (B) a Mannicfi.dispersant having in its structure an aliphatic hydrocarbon-s:ubstituted phenolic group OH

R~ ~ 2`
?cH
wherein R" is an aliphatic hydrocarbon group contain-ir,g 1 tu 500 carbon atom~ and rl is 1 or 2, m is O or 1, n + m is 1 or 2, at least one of said R" groups being an aliphatic hydrocarbon group containing 50-50`0 carbon atoms~, sand phenolic group being bonded through a methylene group to a nitrogen atom o~ an amine? said amine containing 1 to l~.nitrogen atoms and 1 to 30 carBon at~ms~
$everal examples of the Boronated syccinimide dispersant are known in the pr~or art identi~ied above. The ~oronated succinimide dispersant can ~e made by reacting an aliphatic Bydrocarbon-s-u~stituted succi~nic acid anhydride or lower alkyl ester with an oxyalkylated amine and a mab/~

. ~ .

boronating agent in ~he approximate mole ratio of 1.0:0.2-

2.0:001-5Ø The prefe~red succinic reactant is an ali-phatic hydrocarbon-substituted succinic anhydride in which the aliphatic hydrocarbo~ group has a molecular weight of 700-50,000. The aliphatic hydrocarbon group is preferably derived from an olefin polymer such as polypropylene, polybutene, ethylene-propylene copolymer, ethylene-propylene-1,4-hexadiene copolymer, ethylene-propylene--1,4-cyclo-hexadiene copolymer, ethylene-propylene-1,5-cycloctadiene copoly~er, ethylene-propylene-s-methylene-2 norbornene, or ethyleneTpropylene-2~5~norbornadiene copolymer.
The most preferred aliphatic hydrocarbon sub-s~ituellt is derived from an olefin polymer having a mole-cular weight of 700-5000. These include the olefin polymers mentioned above which have the more preferred molecular weight~ Of the above, polybutene is most preferred.
Optionally, a high molecular weight of olefin polymer, for example, one having a molecular weight of 50,000 or more can be degraded to pro~uce an olefin polymer having a more preferred molecular wei~ght. ~ethods o~ reducing the carbon chain length of olefin polymers by shearing are well known.
Mere heati~ng with mechani~cal stirring will reduce molecular weight. Air can be i~n~ected into heated polymer to cause degradation and reduce molecular weight. Extrusion through an orifice under pressure causes chain scission. Any combination of such methods can be used.
Highly preferred olefin polymers for use in m~k~ng the succinic substituent are polymers of butene. 0f these, the most preferred are the polybutenes having an

3~ average molecular weight of 700-2000.
The hydrocarbon substituent can be introduced by heating a mixture containing the olefin polymer and maleic anhydride to 200-250C. T~e reaction can be cata-lyzed by injecting chlorine. Likewise~ a peroxide catalyst can be used. The rçaction is preferably conducted in a mineral oil diluent whic~ can remain in t~e succinic product to act as a solvent in later stages of the preparation.
The aliphatic hydrocarbon-substituted succinic anhydrides are well known~ `

.

` mab/~' .

86~

The oxyalkylated amines are readily made by reacting an alkylene oxide with an amine having primary and/or secondary amine groups. The preferred alkylene oxides are ethylene oxide, propylene oxide 9 and butylene oxide. The more preferred are ethylene oxide and propylene oxide or mixtures thereof. The most preferred oxyalkylating agent is ethylene oxide.
The amines which are oxyalkylated are those containing 2 to 10 nitrogen atoms. More preferably, they also contaln about 2-20 carbon atoms. Some exam~les of these amines are ethylenediamine~ 1,2-propylenediamine, 1,3-propanediamine, N-aminoethyl piperazine, N-oleylamino-propyl-1,3-propane diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine, N-dodecyl ethylenediamine, N-dodecyl-1,3-propane diamine, N-octadecyl diamine, N-(decylaminoethyl)ethylenediamine and the like.
The preferred amines for use in making the succinic dispersants are the polyalkyleneamines. They are sometimes referred to as alkylene polyamines or polyalkylene polyamines. These amines consist mainly of polyamines having the structure H2N ~ R -NH~

wherein R"' is a divalent aliphatic hydrocarbon group con-taining 2 to about 4 carbon atoms and p is an integer from 1 to 6. Representative examples are ethylenediamine, 1,2-propylenedismine, 1,2-butylenediamine, 1,3-propanediamine, diet~lylenetriamine, triethylene tetramine, tetraethylene pentamine (TEP~), pentaethylene hexamine, hexaethylenehep~-amine and the like. Of these, the most preferred are the polyethyleneamines containing Z to 6 ethylene amine units such as diethylene triamine, triethylene tetramine, tetra-ethylene pentamine, and the like, including mixtures thereof.
Reaction of the alkylene oxide with the amine forms hydroxyalkyl groups having the formula H~OR'~ N =
wherein Rl is a divalent aliphatic hydrocarbon group contain-ing 2 to 4 carbon atoms and p is an lnteger from 1 to 10.

mab/, ~U ~

The value of p depends upon how many moles of alkylene oxide are reacted per mole of amine. Preferably, the amount of alkylene oxide reacted is sufficient to provide an average of 1-4 oxyalkylene units per molecule of amine.
More preferably, the molecules of alkylene oxide reacted are at least one less than the number of equivalents of reactive amine groups in the amine. A re-active group is one that has at least one hydrogen atom bonded to it -- in other words, primary or secondary amine groups. For example, one mole of ethylenediamine has two reactive amine groups and hence represents two equivalents.
Likewise, one mole of tetraethylene pentamine is five equi-valents. Therefore, one mole of ethylenediamine is preferably oxyalkylated with up to one mole of alkylene oxide. Like-~ise, one mole of tetraethylene pentamine is preferably oxyalkylated with up to 4 moles of alkylene oxide. The Minimum amount of alkylene oxide is 0Ol moles per mole of amine; more preferably, 0.5 mole of amine. Hence, the preferred amount is 0.5-~ moles.
Oxyalkylation introduces hydroxyalkyl groups.
Rather than carrying out the oxyalkylation of tha amine, it is also possiblè to àcquire hydroxyalkyl substituted amines from commercial sources, and use these in making the succinic dispersant. This is considered equivalent.
Boron is introduced into the succinimide addi-tivs by use o a boronating agent as shown in the pa~ents identified above.
Suitable boronating agents include any boron compound tha~ will serve to introduce boron into the succin-lmide and not adversely affect the dispersant properties o thP additive combination. Useful boronating agents lnclude boron oxides such as B203, boron acids such as B03, lower alkyl esters of boron acids such as trimethyl-borate or triethylborate, boron halides such as BF3, or BC13, salts of boron acids, such as sodium borate, or ammonium borate and the like. The most preferred boronating agent is boric acid.
The amount of boronating agent should be an amount suf~icient to introduce at least 0.001 weight percent boron into the succinimide product excluding inert diluent such as mineral oil. The preferred amount of boron in the mabt~

succinimide exclusive of diluent is 0.001-2.5 weight percent, more preferably 0.005-0.5 weight percent. Excess boronating agent can be used and any remaining unreacted can be re-moved by filtration.
The boronated succinimide dispersant can be made by reacting the aliphatic hydrocarbon~subs~ituted succinic acid, anhydride or ester with the oxyalkylated amine and the boronating agent. These can be reacted in any sequence or altogether. For example, the borona~ing agent can be reacted with the oxyalkylated amine to form an inter-mediate which is then reacted with the succinic compound.
Alternatively, the boronating agent can first be reacted with the succinic compound to form an intermediate which is then reacted with the oxyalkylated amine.
More preferably, the boronated succinimide dis-persant is made by one of the following two procedures. In the first procedure, the hydrocarbon-substituted succinic compound ~preferably polybutenyl substituted succini~ an-hydride) is reacted with the oxyalkylated amine (preferably oxyethylated polyethyleneamine) to fo~m an intermediate which is then reacted with the boronating agent (preferably boric acid).
In a second more preferably procedure, a mix-ture of all three reactants (i.e. hydrocarbyl succinic com-pound, oxyalkylated amine and boronating agent) is formed and heated to react all at once.
The reaction temperature is not critical. Any temperature high enough to cause the reaction to proceed but not so high as to cause degradation of the reactants or products can be used. A preferred temperature range for use in any of the different methods of making the boronated succinimide iæ 100-300C, more preferably, 150-250C.
The aliphatic hydrocarbon-substituted succinic compound reacts with the oxyalkylated amine to form amides, imides, esters and mixtures thereof. These are referred to collectively herein as succinimides. Imide forma~ion can be shown by the following structure R- CH- C//
¦ ~N
CH - C\

in which the remaining bond on nitrogen is bonded to the ~r mab/~
.

remaining part of the oxyalkylated amine. Amide formation c~n be illustrated by the structure R- CH- 3_ N
2 ~
Likewise, ester formation involving the hydroxyalkyl group formed in the oxyalkylation can be shown as follows R--CH~O-R'~--nN =
CH2 C,~

In practice, the product is a mixture of imides, amides and esters with the ma~ority of the product having succinimide units.
The second required component of the synergistic combination is the Mannich dispersant made from an aliphatic hydrocarbon-substituted phenol, an a3dehyde, or aldehyde precursor and an amine having at least one primary or secondary amine group. This leads to a Mannich condensate which can be defined by the presénce within its structure of an aliphatic hydrocarbon-substituted phenolic group having i the formula OH

( Rl ) n~-~ CH

( 2 )m wharein R" is an aliphatic hydrocarbon group containing one to about 500 carbon atoms, and n is one or two, m is O or 1 and n ~ m is 1 or 2. At least one Rl1 group contains about 50-500 carbon atoms. The methylene bridge(s) is(are) bonded to a nitrogen atom of the amine. Such dispersants are well known as identified by the prior art patents listed above.
The Mannich dispersants are readily made starting with an aliphatic hydrocarbon-substuted phenol having the formula OH

(RlI)D ~

wherein R" and n are as previously defined. These compounds can be made by reacting an olefin having the proper molecular - 7 ~
- mab/l~

weight with phenol or a monoalkyl substituted phenol. The olefin should contain 50-500 carbon atoms ~hich give a molecular weight of 700-7000. The olefin reactant is preferably made by polymerizing a lower olefin such as ethylene, propylene, isobutylene, ~-he~ane 7 ~-octen~ and mixeures thereof. Thus, useful olefin polymer reactants are polybutene, polypropylene, ethylene~propylene copolymer, and the like. Terpolymers can also be used to introduce the aliphatic hydrocarbon group. These include ethylene-propylene copolymers with dienes such as 1,4-hexadiene, 1,5-hexadiene, 1,4-cycloctadiene, dicyclopentadiene, and the like.
The more preferred aliphatic hydrocarbon-sub-stitute~ phenol reactant is polybutenyl pheno] made by re-acting a polybutene of ~00-~000 molecular weight with phenol using a BF3 catalyst such as BF3 phenate or etherate at 0-6QC. Some more p~eferred reactants are those in which the polybutenyl group has a molecular weight of 1000-3000.
The methylene bridge attached at one end to the phenol is introduced by reaction with an aldehyde such as formaldehyde or a formaldehyde precursor such as paraform-aldehyde. One or two such ~ridges may orm.
The other end of the methylene bridge i5 bonded to a nitrogen atom of an amine. Preferred amines contain l to about 10 nitrogen atoms and l to about 30 carbon atoms.
~ore preferred amines are aliphatic a~ines. Examples of such amines are methyl amine, ethyl amine, isobutyl amine, lauryl amine, oleyl amine, stearyl amine, eicosamine9 tri-contamine, N~propylethylene diamine, N-dodecyl-1,3-propane-diamine, N-(dodecyl ami`noethyl~ ethylene diamine, N-(eicosyl-ami~noethyl2 ethylenediamine, N~aminoethylpiperazine ? N-aminopropyl piperidi~ne, ethanol amine, N-aminoethylmorpholine, 1~3~propane d~amine ? N,N~dimethyl-1,3-propaned-iamine, 1,6-hexane diamine and the like.
A preferred class of amines for use in making the Mannich dispersants is the polyalkyleneamines which were also a preferred class of amines for use in making the succinimide dispersants. They were previously described and exemplified.
~atty acids useful in modifying the Mannich dispersants include the aliphatic carboxylic acids containing mab/f~

4 to about 30 carbon atoms. The more preferred fatty acids are those containing about 10-30 carbon atoms such 2S
capric acid, undecylic acid, lauric acid, tridecoic acid, myristic acid, palmitic acid, linoleic acid, stearic acid, arachidic acid and the like. The preferred fatty acid is oleic acid. The use of such fatty acids in modifying Mannich dispersants is described in more detail in the above-identified patents.
Boron compounds useful in modifying the ~lannich dispersant are the same boron compounds used to boronate the succinimide dispersants. These are boron oxides, boron acids, esters of boron acids, salts of boron acids~ boron halides, and mixtures thereof. The preferred boronating agent is boric acid. Use of such boronating a~ents in modifying Mannich dispersants is described in more detail in the hereinabove identified patents.
The Mannich dispersants are made by reacting about one mole of aliphatic hydrocarbon-substituted phenol, 0.9-2.5 moles of formaldehyde or formaldehyde precursors, 2~ 0.1-2.0 moles of amine, 0 to 3 moles of fatty acid and 0 to 2.0 ~oles of boronating agent. These can be reacted in any order or altogether. In a preferred method, the Mannich dis-persant is made by heating a mixture of aliphatic hydro-carbon substituted phenol and amine at 60-200C and adding a formaldehyde to the heated mixture to form a Mannich con-densate. If boronated Mannich is used the boronatin~ a~ent (e.g. boric acid~ can be added subsequently to the mixture and heating to 100-250C as the desired amount of boron is introduced. Alternatively, part of the Mannich condensate can be segregated and heated with a boronating agent (e.g.
bor~c acid) to introduce a higher level or boron than is desired in the final Mannich. This overboronated product can then be blended back into the unboronated Mannich to achieve the desired boron level. The final Mannich can be clarified by filtration.
Fatty acid modified Mannich dispersants can ~e made by heating a mi~xture of aliphatic hydrocarbon-sub-stituted phenol, formaldehyde, amine and fatty acid to 50 to 150C. More preferably, the formaldehyde is withheld and added slowly to a mixture of the other reactants while stirring at 50-150C.

mab/l~

The ~annich dispersant can be modified with both boron and fatty acid. This can readily be accomplished by combining the ~oregoing procedures. For example, one can heat a mixture of hydrocarbon-substituted phenol (e.g.
polybutenyl phenol), amine (e.g. tetraethylene pentamine~
and fatty acid (e.g. oleic acid) to reaction temperature and then add formaldehyde and subsequently a boronating agent (e.g. boric acid). Alternatively~ one can form a mixture of hydrocarbon-substituted phenol, amine, boronating agent and fatty acid and add formaldehyde to ~he heated mixture. In another procedure, the Mannich condensate of hydrocarbon-substituted phenol formaldehyde and amine is split into separate portions. One portion is heated with a boronating agent such as boric acid and the second portion is heated with a fatty acid such as oleic acid to obtain two separate modified intermediate products. These products can then be blended back together to obtain a Mannich con-densate which is both boron and fatty acid modified. Other reaction sequences involving the condensation of hydrocarbon-substituted phenol, amine, formaldehyde, boronating agent, and fatty acid will be apparent to the average chemist.
The following examples illustrate the prepara-~ion oE the succinimide type dispersants.

In a reaction vessel was placed 1080 grams ~6.0 moles) o~ a mixture of polyethyleneamine having an average composition corresponding to tetraethylene pentamine.
Thls was stirred under nitrogen and heated to about 120C.
Tllen 441 grams (10.0 moles~ of ethyle~e oxide was injec~ed over a 3.5 hour period to form an oxyethylated polyethylene-~ine.
In a second reaction vessel was placed 101.6 grams (about 0.4 moles~ of the above oxyethylated poly-ethyleneamine, 28.8 grams (0.47 moles) of boric acid, 9.6 grams of water and 727 grams (about 0.6 moles) of a poly-butenyl succinic anhydride. ~his mixture was stirred under nitrogen and heated to 175C over a three hour period.
It was then stirred for an additional hour at 175C while vacuum was applied to remove residual water. The product was diluted with one-half its weight of mineral oil to be 67 percent active dispersant. It was clarified by filtra-tion. Analysis gave amine number 0.85, acid number 0.09 ~ mab/~

nitrogen 1.84 weight percent, boron 0.3 weight percent.
EX~MPLE 2 In a reaction vessel was placed 1124 grams (1.3 moles) of polyisobutenyl succinic anhydride and 25~
grams (1~0 mole) of oxyethylated polyethyleneamine made by reaction about 1.67 moles of ethylene oxide with one mole of polyethyleneamine having an average molecular weight of 180. This mixture was heated under nitrogen to 175C
while bubbling nitrogen through the liquid and maintainin~
a vacuum of about 26.5 inches (Hg) for 4.5 hours. The resultant product was diluted with mineral oil to give a 67 percent active material. Then 75 grams (1.2 moles~ oE
boric acid and 25 grams of water were added. The mixture was heated to 100C and nitrogen sparge continued for two IlOUrS. It was then heated to 150C and nitrogen sparge continued for two hours. The product was filtered to obtain a clear boronated succinimide dispersant for use in the synergistic combination. It analyzed 2.42 weight percent nitrogen, 0.49 weight percent boron, amine number 1.16 total base number 34.4 and acid number 0.03.

In a reaction vessel was placed 396 grams (2.2 moles~ of polyethyleneamine having an average composi-tion corresponding to tetraethylene pentamine. This was heated to 120C and 162 grams (3.7 moles) of ethylene oxide was injected into the amine at 120-140 over a 2.5 hour period.
In a second reaction vessel was placed 254 grams (about 1 mole) of an oxyethylated polyethyleneamine, ~3 ~rams (1.5 moles) boric acid and 47 grams of water. This was stirred at 100C with nitrogen sparge for three hours.
It was then heated to 150C and nitrogen sparge continued for two hours to obtain a boronated-oxyethylated polyethylene-amine.
~In another reaction vessel was placed 1798 grams ~1.6 moles) of polybutenyl succinic anhydride and 222 (0.75 moles) of the above boronated-oxyethylated polyethyl-eneamine~ This mixture was placed under vacuum with nitrogen sparge and heated to 175C for 4.5 hours. The product was diluted with mineral oil to be 67 percent active. It anal-yzed 0.2 weight percent boron.

~ 11 -~ r r EXAMPLE _4 In a reaction vessel was placed 1487 grams (1.6 moles) of polybutenyl succinic anhydride, 74 grams (1.5 moles) boric acid and 24 grams of water. This mix~ure was stirred and heated under nitrogen at 100C Eor three hours, and then at 150C under vacuum for two hours. To this was then added Z03 grams (0.8 mole) of an oxyethylated polyethyleneamine made by reacting 1.67 moles of ethylene oxide with 1 mole of polyethyleneamine having the average composition of a tetraethylene pentamine. This mixture was heated at 175C with nitrogen sparge under vacuum for 4.5 hours. The final product was diluted with one-half its weight in process oil to give a 67 percent active product and analy~ed 0.13 weight percent boron.
The following example illustrates a method for making the Mannich dispersants.

In a reaction vessel was placed 2019 grams of heptane~ 529.7 grams of polybutene (mole weight 1000) and 79.5 grams of phenol. To this was added 23.9 grams of BF3 phenate over a 20-minute period at 40C~ The mixture was then stirred for 90 minutes at 40C. It was then washed at 60-70C with aqueous ammonia and then with water and finally with methanol, leaving behind the polybutenyl phenol. This was cooled to about 40~C and 59 grams of N,N-dimethyl-1,3-propanediamine was added and stirred. Then 2~.2 grams of formaldehyde was added incrementally over a 30-minute period at 40-50C. Stirring was continued for 30 mlnutes and then the mixture was heated to about 130C
whlle distilling out volatiles. It was stirred three hours at 130C under slight nitrogen pressure and then heated to 170C and vacuum applied to 50 mm. Hg. abs to complete removal of yolatiles, It was then diluted with about 380 grams- of hydrocarbon solvent and cooled giving a Mannich dispersant useful in the present combination.
Other Mannich dispersants can be made following the above general procedure by substituting any of the previously disclosed primary and secondary amines in place of N,N-dimethyl-1,3-propanediamine. For example, tetra-ethylene pentamine on an equal mole basis yields an effec-tive dispersant which may be readily modified by heating with boric acid and/or oleic acid to improve its properties, - ~2 -` mab~

especially with regard to corrosiveness.
Each of the two types of synergistic addi~ives is used in lubricating oil at a concentration which ma~i-mizes their total effectiveness at an acceptable cost. A
useful concentration range for each is 0.05-lO weight per-cent. A mo~e preferred range is 0.5-5 weight percent and a highly preferred range is 1-3 weight percent. These concentrations do not includeany~mineral oil diluent incor-porated into the additive during manufacture.
The additiyes can be used in mineral oil or in synthetic oils of viscosity suitable Eor use in the crankcase of an internal combustion engine. Crancase lubri-cating oils haye a viscosity up to about 0.0000159 m2/sec.
at 210F.
Crankcase lubricating oils o~ the present in-vention have a viscosity up to about SA~ 50. Sometimes such motor oils are given a classification at both 0 and 210F. such as SAE lOW 40 or SAE SW 30.
~ ineral oils include those of suitable Vi5-cosi~y re~ined from crude oil from sources including Gulf-cosst, midcontinent, Pennsyl-vania, mideast, California 9 ~laska, North Sea, and the like. Various standard refinery operations can be used in processing the mineral oil.
Synthetic oil includes both hydrocarbon synthetic oil a~d synthetic esters. TJseful synthetic hydro-carbon oils include liquid polymers of ~-olèfins having the proper viscosity. Especially useful are the hydrogenated liquid oligomers of C6 12 ~-olefins such as ~-decene trimer.
Likewise, alkylbenzenes of proper viscosity can be used,~
such as didodecylbenzene.
Useful synthetic esters include the esters of both monocarboxylic acid and polycarboxylic acid as ~ell as monohydroxy alkanols and polyols. Typical examples are didodecyl adipate, trimethylol propane tripelargonate, pentaerythritol tetracaproate, di-(2-ethylhexy-l)adipa~.e, dilauryl sebacate and the like. Complex esters prepared from mixtures of mono- and dicarboxylic acid and mono- and polyhydroxyl alkanols can also be used.

mab/~

I ~ n 4~ ~

Blends of mineral oil with synthetic oil are particularly useful. ~o~ example~ blends of 10-25 weight percent llydrogenated ~-decene trime~ with 75-90 weight percent 0.00003~1 m /sec. (100F) mineral oil results in àn excellent lubricant. Likewise, blends of about 10-25 weight percent di(2-ethylhexyl~adipate with mineral oil of proper viscosity results in a superior lubricating oil.
Also blends of synthetic hydrocarbon oil with synthetic esters can be used. Blends of mineral oil with synthetic oil are especially useful when preparing low viscosity oil (e. g. SAE 5~ 20) since they permit these low viscosities ~ithout contributing excessive volatility.
The more preferred lubricating oil composition includes zinc dihydrocarbyldithiophosphate ~ZDDP) in combi-nation with the present additives. Both zinc dialkyldithio-phosphates and zinc dialkaryldithiophosphates as well as mixed alkyl-aryl ZDDP are useful. A typical alkyl-type ZDDP contains a mixture of isobutyl and isoamyl groups.
Zinc di-tnonylphenyl)dithiophosphate is a typical aryl-type ~O ZDDP.- Good results are achieved using sufficient ZDDP to provide 0.01-0.5 weight percent zinc. A preferred concen-tration supplies 0.025-0.3 weight percent zinc.
Another additive used in the oil compositions are the alkaline earth metal petroleum sulfonates or alkaline earth metal alkaryl sulfonates. Examples of these are calcium petroleum sulonates, magnesium petroleum sulfonates, b~nrium alkaryl sulfonates, calcium alkaryl sulfonates or magneslum alkaryl sul~onates. Both the neutral and the over~ased sulfonates having base numbers up to about 400 can ~e ~eneficially used. These are used in an amount to provide about 0.05-1.5 weight percent alkaline earth metal and more preferably about 0.1~1.0 weight percent. In a most preferred embodiment the lubricating oil composition contains a calcium and!or magnesi~um petroleum sulfonate or alkaryl (e.g. alkylbenzene),sulfonate. `
Other viscosity index i~pro~ers can be in-cluded such as the polyalkylmethacrylate type or the ethyl-ene-propylene or ethylene-propylene~dienecopolymer type.
Likewise, styrene-diene VI improvers or styrene-acrylate -, copolymers can be used. Alkaline earth metal salts of phosphosulfurized polyisobutylene are useful.

~r - 14 -i~ mab//~ ~

6 /~ ~3 - Tests were conducted which demonstrated the substantial synergistic effect of the present invention.
The test used ~as industry-recognized AST~ Sequence VD engine test. In Lhis test, a Ford Pinto engine is opera~ed on a fixed schedule with the test oil in the engine crankcase.
After ~he operating schedule is complete, the engine is dis-assembled and various parts rated for cleanliness using a standard rating scale of 1-10 in which 10 is clean.
The base test oil was a fully formulated mineral oil. The only difference between the test oils was the d~ispersant. The dispersant varied as follows:
- Percent Test Oil Dispersant ~Concentration A ` Oxyethylated-boronated polybutenyl- 7.0 succinimide of polyethyleneamine (TEPA~
B Boronated polyl~utenylphenol-~orm- 7.0 aldehyde-polyethyleneamine Mannich condensatel C Dispersant from A 3.0 Dispersant from B 2.0 lCommercial dispersant "Amoco 9250" from Amoco Chemical Corporation.
The test results are shown in the following table:
Test Oil A B C
Average sludge 9.4699.43 9.63 9.55 Average varnish 6.94,7.1' 8.00 8.55 Piston varnish 7.34,7.68 7.30 8.26 Note that Oil C containing the synergistic combination gave a mùch better average varnish and piston varnisll rating at 5 percent total dispersant than either Oil A or Oil B using the same individual components separately and at a much higher concentration. Hence, the combination gives results superior to the sum of the expected contri-butions of the components.

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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 an oil of lubricating viscosity containing a minor dispersant amount of a synergistic combination of dispersants, said combination comprising (A) a boronated succinimide dispersant having in its structure at least one aliphatic hydro-carbon-substituted succinoyl group wherein R is an aliphatic hydrocarbon group having a molecular weight of 700-50,000, said succinoyl group being bonded to a nitrogen atom of an oxyalkylated amine to form an amide or imide or to an oxygen atom of said oxyalkylated amine to form an ester or to both nitrogen and oxygen atoms of said oxyalkylated amine to form a mixture containing amide, imide and ester groups, said succinimide dispersant being further characterized by containing 0.001-2.5 weight percent boron and (B). a Mannich dispersant having in its structure an aliphatic hydrocarbon-substituted phenolic group wherein R" is an aliphatic hydrocarbon group containing 1 to 500 carbon atoms and n is 1 or 2, m is 0 or 1, n + m is 1 or 2, at least one of said R" groups being an aliphatic hydrocarbon group containing 50-500 carbon atoms, said phenolic group being bonded through a methylene group to a nitrogen atom of an amine, said amine containing 1 to about 10 nitrogen atoms and 1 to 30 carbon atoms.

2. A lubricating oil composition of Claim 1 wherein R is derived from an olefin polymer.

3. A lubricating oil composition of Claim 2 wherein at least one R" is derived from an olefin polymer containing 50-500 carbon atoms.

4. A lubricating oil composition of Claim 1 wherein said oxyalkylated amine is an oxyalkylated poly-alkyleneamine wherein said alkyleneamine groups are ethylene-amine, propyleneamine, or mixtures thereof.

5. A lubricating oil composition of Claim 4 wherein R is a polybutenyl group having a molecular weight of 700-5000 and at least one R" group is a polybutenyl group having a molecular weight of 1000-3000.

6. A lubricating oil composition of Claim 5 wherein said oxyalkylated polyalkyleneamine is an oxyethyl-ated polyethyleneamine containing one to 6 ethyleneamine units.

7. A lubricating oil composition of Claim 1 wherein said boronated succinimide dispersant is made by a process comprising reacting in any sequence or altogether (a) 1 mole of a polybutenyl succinic anhydride wherein said polybutenyl group has a molecular weight of about 700-5000, (b) 0.2-2.0 moles of an oxyalkylated poly-ethyleneamine containing 1 to about 6 ethylene-amino units, and (c) 0.001 to about 5.0 moles of a boron com-pound selected from the group consisting of boron oxides, boron acids, esters or boron acids, salts of boron acids, boron halides, and mixtures thereof.

8. A lubricating oil composition of Claim 7 wherein said polybutenyl group has a molecular weight of 700-2000, said oxyalkylated polyethyleneamine contains an average of about 1-4 oxyethylene units per molecule of poly-ethyleneamine and said polyethyleneamine contains an average of 2-6 ethyleneamino units per molecule.

9. A lubricating oil composition of Claim 8 wherein said boron compound is a boric acid

10. A lubricating oil composition of Claim 7 wherein said Mannich dispersant is made by a process com-prising reacting in any sequence or altogether (a) one mole of a polybutenyl phenol wherein said polybutenyl group has a molecular weight of 700-7000, (b) 0.9-2.5 moles of formaldehyde or a forma-ldehyde precursor, (c) 0.1-2.0 moles of an amine containing 1 to 30 carbon atoms and 2 to 10 nitrogen atoms, at least one of which is a primary amine group, (d) 0 up to about 3 moles of a fatty acid, and (e) 0 up to about 2.0 moles of a boron com-pound selected from the group consisting of boron oxides, boron acids, esters of boron acids, salts of boron acids, boron halides, and mixtures thereof.

11. A lubricating oil composition of Claim 10 wherein said amine containing 1 to 30 carbon atoms is N,N-dimethyl-1,3-propanediamine.

12. A lubricating oil composition of Claim 10 wherein said amine containing l to 30 carbon atoms is a polyethyleneamine containing an average of 1-6 ethyleneamino units.

13. A lubricating oil composition of Claim 12 wherein said fatty acid in (d) is oleic acid in an amount of 0.1-2.0 moles per mole of said polybutenyl phenol and said boron compound in (e) is boric acid in an amount of about 0.01-l.0 moles per mole of said polybutenyl phenol.

14. A lubricating oil composition of Claim 10 wherein said oxyalkylated polyethyleneamine is an oxy-ethylated polyethyleneamine containing an average of 2-6 ethyleneamino units per molecule and 1-4 oxyethylene units per molecule and said boron compound used to boronate said succinimide dispersant is a boric acid.

15. A lubricating oil composition of Claim 14 wherein said polybutenyl group of said polybutenyl phenol has a molecular weight of 1,000-3000.

16. A lubricating oil composition of Claim 15 wherein said fatty acid is oleic acid in an amount of 0.1-2.0 moles per mole of said polybutenyl phenol and said boron compound used in making said Mannich dispersant is a boric acid in an amount of 0.01-1.0 moles per mole of said polybutenyl phenol.

17. A lubricating oil composition of Claim 16 wherein said amine containing 1 to 30 carbon atoms is a polyethyleneamine containing an average of 1-6 ethyleneamino units.

18. An additive package formulated for addi-tion to lubricating oil to obtain a formulated motor oil suitable for use in an internal combustion engine, said package containing a synergistic combination of dispersants comprising (A) a boronated succinimide dispersant having in its structure at least one aliphatic hydro-carbon-substituted succinoyl group wherein R is an aliphatic hydrocarbon group having a molecular weight of 700-50,000, said succinoyl group being bonded to a nitrogen atom of an oxyalkylated amine to form an amide or imide or to an oxygen atom of said oxyalkylated amine to form an ester or to both nitrogen atoms and oxygen atoms of said oxyalkylated amine to form a mixture containing amide, imide and ester groups, said succinimide dispersant being further characterized by containing 0.001-2.5 weight percent boron and (B) a Mannich dispersant having in its structure an aliphatic hydrocarbon-substituted phenolic group wherein R" is an aliphatic hydrocarbon group containing 1 to 500 carbon atoms and n is 1 or 2, m is 0 or 1, n + m is 1 or 2, at least one of said R" groups being an aliphatic hydrocarbon group containing 50-500 carbon atoms, said phenolic group being bonded through a methylene group to a nitrogen atom of an amine, said amine containing 1 to 10 nitrogen atoms and 1 to 30 carbon atoms.