CA1169845A - Synthetic olefin oligomer base oil composition and its use in manual and automatic transmissions - Google Patents

Abstract

Abstract of the Disclosure Synthetic base oils made by oligomerization of hydrocarbon olefins are useful as base oils for preparing lubricating oils to be used in manual and automatic auto-motive transmissions. These transmission oils contain minor amounts of phosphorus- and sulfur-containing extreme pres-sure agents. The oils have certain viscosity, phosphorus, and sulfur properties which make them useful as transmission oils.

Description

:

9~5 SYNTHETIC OLEFIN OLIGOMER BASE OIL COMPOSITION
AND ITS USE IN MANUAL AND AUTOMATIC TRANSMISSIONS

Background of the Invention 5 Field of the Invention This invention relates to transmission oils to be used in manual and automatic automotive transmissions. More particularly, it relates to manual and automatic transmis-sion oils based on oligomers prepared from hydrscarbon-based 10 olefins and extreme pressure agents. These extreme pressure agents contain the elements phosphorus and suIfur.
Discussion of Prior Art ~ he lubrication of manual transmissions to be used in vehicles such as automoblles and trucks has, for years, 15 been known to involve particular problems requiring specific solutions. For example, it is necessary to adequately lubricate the transmission at low temperature to prevent the phenomenon known as cold clashing. At ~he same time, it is desirable that the same oil be used to prevent problems 20 developing in hot transmissions such as hot rattling and excessive rollover noise. Improperly functioning manual transmissions which often resuIt from poor lubrication can both waste fuel and present dangerous operating conditions which sometimes result in serious accidents.
In the lubrication of automatic transmissions, ; proper fluid viscosity at both 1GW and high temperatures is . , . . ~ ~

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essential to successful operation. Gooa low temperature fluidity eases cold weather starting and insures that the hydraulic control system will properly "shift geaxs". High viscosity at elevated temperatures insures pumpability and the satisfactory functioning of converters, valves, clutches, gears and bearings.

These conflicting fluidity requirements call for a product that shows the following properties:
a) High temperature viscosity retention b) Low temperature fluidity c) Shear stability.
Therefore, the search for useful oils to use in manual and automatic transmissions under all conditions of operation is of -continuing interest.

The use of synthetic oils derived from oligomerization of olefins, particularly hydrocarbon olefins, is known; see, for example, the compilation "Synthetic Oils and Greases for Lubricants - Recent Developments" by M. William Ranney, published by the Noyes Data Corporation, Park Ridge, New Jersey, U.S.A., 1976, particularly pages 292-304. In general, these oils have been used as crankcase lubricants. See, for example, U.S. Patent 4,175,047 to Schick et al. Various patents and other prior art references have described useful techniques for producing such oils and compounding them; see, for example, U.S. Patent 3,149,178 to Hamilton et al.; 3,682,823 to Smith et al.; 3,780,128 to Shubkin; 4,032,591 to Cupples et al.;
4,167,534 to Petrillo et al.; and 4,175,046 to Coant et al.

Summary of the Invention This invention provides an oil composition comprising:
lA) A carboxylate ester-free base oil comprising a major amount of a synthetic, liquid, hydrocarbon~based ~,~ , olefin oligomer; and ~ B) A minor amount of extreme pressure agent con-taining phosphorus and sulfur, said oil composition having a viscosity of less 5 than about 100,000 cPs at -40C. (according to ASTM Method D-2983), a phosphorus content of less than about 0.10 weight percent, and a sulfur content of less than about 1.5 weight percent.
Methods of operating an automotive manual trans-10 mission which comprise lubricating said transmission withthe aoredescribed oil composition as well as automotive manual transmissions containing the oil composition are also within the scope of ~he inv~ntion.
This invention also provides a method of operating 15 an automatic automotive transmission which comprises lubri-cating the transmission with an automatic transmission fluid composition comprising:
(A-l) A base oil comprising a major amount of a syn-thetic, liquid, hydrocarbon-based olefin oligomer, and (B) A minor amount of extreme pressure agent con~
~ taining phosphorus and sulfur, - said automatic transmission fluid composition having a viscosity of less than about 50,000 cPs at -40C.
taccording to ASTM Method D-2983), a phosphorus content of 25 less than about 0.10 weight percent and a sul~ur content of less ~han about lo5 weight percent.
The compositions of this invention solve the low temperature problems of manual and automatic transmissions described hereinabove, while maintain.ing the necessary high 30 temperature protection. The compositions of this invention provide excellent lcw temperature fluidity which, when used in automatic transmissions, results in improved fuel economy, startability, and operation at low temperatures. The compo~
sitions of this invention also provide improved oxidation 35 inhibition properties. Furthermore, the compositions of this inven~ion have unexpectedly high shear stability.
Additionally, khe compositions of thiS invention provide excellent viscosity index (VI~ properties which eliminates or reduces the need for VI improver additives. This is 5 particularly helpful in automatic transmission fluids where VI properties are important.
Detailed Description of the Invention (A) The synthetic olafin oligomer.
As indicated above, the oil compositions of this 10 invention comprise at least one carboxylate ester-free base oil which, in turn, is comprised of a major amount of at least one synthetic, liquid, hydrocarbon-based olefin oli-gomer. These base oils are carboxylate ester-free. This means they contain less than five percent carboxylate ester, 15 particularly those carboxylate esters known to be useful as synthetic ester lubricants. See, ~or example, the car-boxylate esters described in the text "Synthetic Lubricants"
by Gunderson and Hart, Reinhold Publishing Corporation (1962), pages 151-241, and 388-399 and the aforecited U.S.
20 Patent 4,175,047.
The description of oils used in the present in-vention as "base oils" reflects the fact that the oil com-positions are based upon them; in other words, the oils are the predominant oils in the lubricating oil composition.
25 These oil compositions contain more than 50 percent by weight~ generally, more than about 70 percent, often as much as 85 or 95 percent synthetic olefin oligomer oil. These olefin oligomer oils can be admixed with various other types of oils either hydrocarbyl or not tas long as the other 30 descriptive parameters are met~. Specific examples include alkylated benzene oils, silicate oils, polyglycol-based oils, and the like. Many such useful synthetic oils are known to the art. The synthetic oligomer oils of this invention can also be combined with various natural oils 35 such as those derived from mineral sources tpetroleum, coal, 3~5 shale, etc.) as well as other sources such as vegetables and animals. Typically, however, the oil compositions of the present invention contain base oils consisting essentially of synthetic olefin oligomer oil.
The synthetic oligomer oils of the present in-vention are liquid at room temperature and exhibit fluid flow at this temperature. Furthermore, their viscosity properties are such that at -40C. the viscosity of the oil compositions ba~ed upon them can be m~asured by ASTM Method 10 D-2983 and found to be less than abou~ 100,000 cPs at this temperature. This can be accomplished by ha~lng an olefin oligomer oil of the proper viscosity in itself or by blend-ing an olefin oligomer with one or more other oils as indi-cated above to provide the desired viscosity properties.
The oil compositions of the present invention have a viscosity of less than about 100,000 cPs at -40C. as measured by ASTM Method D-2983. Often they have a viscosity less than about 12,000 cPs at -40C. Typically, the oils of this invention have viscosities of less than about 20 cen 20tistokes at 100C. More usually, the oil compositionls vis-cosity is less than about 12 centistokes at 100C.
The olefin oligomer oils upon which the oil compo-sitions of this invention are based are hydrocarbon-based in nature. The term "hydrocarbon-based", when used herein, 25denotes a compound, composition and 50 forth having pre-dominantly hydrocarbon character within the context of the invention. Such materials include the following:
1. Hydrocarbon compounds, compositions, etc., that is, aliphatic, (e.g., alkyl or alkenyl), alicyclic 30 (e.g., cycloalkyl or cycloalkenyl), aromatic, aliphatic- and alicyclic-substituted aromatic, aromatic-substituted alipha-tic and alicyclic materials, and the like.

2. Substituted hydrocarbon compounds, compo-sitions, etc., materials containing non-hydrocarbon substi-35tuents which, in the context of this invention, do not alter ~ i9 ~ ~ ~

the predominantly hydrocarbon character of the material.Those skilled in the art will be aware o suitable sub-stituents; examples are: ~ R
halo, nitro, cyano, RO-, R -, ROC-R~N, R2NC-, (R being hydrogen or a hydrocarbon radical).

3. Hetero compounds, compositions, etc.; that is, materials which, while predominantly hydrocarbon in 10 character within the context of this invention, contain atoms other than carbon present in a chain or ring otherwise composed of carbon atoms. Suitable hetero atoms will be apparent to those skilled in the art and include, for example, oxygen, sulfur and nitrogen.
In general, no more than about three substituents or hetero atoms, and preferably no more than one, will be present for each 10 carbon atoms in the hydrocarbon-based compound, composition or material.
~erms such as "alkyl-based" and the like have 20 meanings analogous to the above with respect to alkyl materials and the like.
Preferably, the olefin oligomer base oils in the oil compositions of this invention are purely hydroaarbyl.
Usually this means that the olefins used to make them are 25 also purely hydrocarbyl in character.
The oligomeric base oils o~ this invention are made by oligomerizing one or more olefins to make a product which can serve as the base oil itself or in admixture as described above. Generally, these olefins will he mono-30 olefins although in certain cases varying amounts of di-olefins, particularly non-conjugated di-olefins, can be used as long as the products provide oils having the appropriate properties. Similarly, these olefins are usua}ly aliphatic in nature and therefore do not contain aromatic groups S3~

although relatively small amounts of aromatic-containing olefins can be used, particularly in admixture. The olefins used to produce the oligomeric base oils of this invention can have the olefinic (double) bond located in any position within their structure. Often a mixture is used having a statistical distribution of double bonds located in all possible positions.
Typically, however, alpha-olefins (l-olefins) are used exclusively or at least predominantly. Usually these alpha-olefins and, indeed, the other internal olefins are normal;
that is, they are straight-chain compounds having no branching.
Branch-chain olefins, particularly in admixture, can also be used. Usually the olefins used in producing the oligomers used as base oils for the oil compositions of this invention contain about 6-18 carbon atoms, usually about 8-12 carbon atoms. A
mixture having a mean carbon content of about 10 carbon atoms (calculated on weight basis) can be used. Usually this fraction is purely hydrocarbyl in nature. As noted above, it is hydrocarbon-bas~d in any event.

Preparation of the olein oligomers used as base oils in the compositions of the present invention can be carried out by many techniques known to those of skill in the art. Among these techniques is cationic polymerization of the aforedescribed olefin mixtures, particularly the normal alpha-olefin mixtures of about 6-18 carbon atoms. Such cationic oligomerizations are usually catalyzed by Lewis acids. A number of such processes have been described; see, for example, U.S. Patents 3,149,178 (-to Hamilton et al.); 3,376,360 (to Feezel); 3,382,291 ~to Brennan); 3,576,898 (to Blake et al.); and 3,763,244 (to Shubkin).

The oligomers used in base oils of the present invention are either hydrogenated oligomers orunhydrogenated oligomers.
Methods for hydrogenating such oligomers are known. See, for ~.ti~3~5 example, the aforementioned '178 patent, as well as U.S.
Patents 3,682,823 ~to Smith et al.); 3,780,128 (to Shubkin);
3,808,134 (to Romine); 4,032,591 (to Cupples et al.); 4,167,53 (to Petrillo et al.); 4,175,046 (to Coant); and 4,175,047 (to Schick). A base oil composed of only hydrogenated or only unhydrogenated oligomers can be used in the oil compositions of this invention. Alternatively, base oils comprised of mixtures of both types of oligomers, that is, hydrogenated/unhydrogenated, either by themselves or in admixture with other materials as indicated above can be used. Typically, however, the mixture is either only hydrogenated oligomers or of only unhydrogenated oligomers.

As indicated above, the base oils of this invention include olefinic oligomers in mixture with other materials such as those described above. Often, however, the base oil contains no more than about 10 percent by weight of natural or non-olefin synthetic oil and, in many cases consists essentially of synthetic, liquid hydrocarbon-based olefin oligomer. Typically, such oligomers are purely hydrocarbyl and of normal alpha-olefins having about 6-18 carbon atoms, often of normal alpha-olefins having a mean ~by weight) carbon content of about 10 carbon atoms.

(B) The extreme pressure agents.
Extreme pressure or "E.P." additives and agents are well known to those of skill in the art. They are also often referred to as load-carrying agents. These materials are chemicals which are added to lubricating oils to prevent metal-to-metal contact between relatively moving surfaces during lubrication. Such metal-to-metal contact can lead to wear and ultimately catastrophic destruction of metal parts.
Descriptions of extreme pressure agents are available in the prior art. See, for example,'lLubricantAdditiv,es" by Smalheer, and Kennedy, Lezius-Hiles Co., Cleveland, Ohio (1967), pages 9-11, particularly, and U.S. Patent 4,162,985.
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g _ The extreme pressure agents used in -the oil com~ositions of the present invention contain phosphorus and sulfur, usually in chemically combined form. This does not mean that a single agent (or even a single compound in a given agent) contains both phosphorus and sulfur though this may be the case. It is sufficient that at least a phosphorus-containing and a second sulfur-containing agent~ or compound be present. Tt is sometimes the case that both elements are present in a single agent or compound. In other cases, one agent or compound may contain both and the other but one In still other cases, each agent or compound of two may contain phosphorus or sulfur. In addition, supplemental agents eontaining neither phosphorus or sulfur can be present. It is only necessary that at least one E.P. agent or combination of E.P. agents containing sulfur and phosphorus be present.

Extreme pressure agents are usually organic compounds in the sense that they contain at least one organic moiety within their structure. They may be metal salts of organo acids in which case there are both inorganic and organic portions to the molecule. In other instances, they may be wholly organic and not contain any inorganic or metallic portion. Among the more typical extreme pressure agents for use in the oil compositions of this invention are the xanthates, sulfurized fatty oils, sulfur chloride-treated fatty oils, phospho-sulfurized fatty oils, benzyl and chlorobenzyl di-sulfides, alkyl polysulfides, mixtures of mono-, di- and tri-alkylphosphites, mixtures of mono- and di-alkarylphosphates, zinc and lead dialkyldithiocarbamates and zinc di-organodithiophosphates. Supplemental extreme pressure agents containing neither phosphorus nor sulfur include chlorinated paraffin waxes, lead soaps such as lead naphthanate, and other materials known to the art. A number of E.P. agents have ~-:r-~.

3~5 been described in the art, including those noted above and still other types; see, for example, the disclosure in "Lubricant Ad~iti~es- Recent Developments" by M.W. Ranney, Noyes Data Corporation, New Jersey (1978), particularly pages 165-204.

Extreme pressure agents used in the oil compositions of this invention are often formulated in additive concentrates or packages and as such may contain one or more inert solvent/
diluents which in turn may constitute one or more oils. Such oils are not considered to be base oils in the sense of this invention and in view of their relatively low concentration in the overall oil compositions of this invention they are not included in the term "base oils" as used herein.

The extreme pressure agent or agents used in the oil compositions of this invention are employed in a concentration so as to yield an oil composition having less than about 0.10 weight percent phosphorus and less than about 1.5 weight percent sulfur. Typically, they contain less than 0.05 percent phosphorus and less than 1.0 percent sulfur, and since the phosphorus and sulfur content of the agent may in itself be a relatively low percentage of its overall weight, this means that the extreme pressure agent can be used in amounts ranging between, for example, about 0.25-10.0 percent phosphorus-containing agent and about 0.25-20 percent sulfur-containing agent. Usually, however, the extreme pressure agent or agents will be used in an amount between, for example, about 0.5-10 percent of each agent. If the agent used contains both phosphorus and sul~ur it is used in concentrations to produce oil compositions having phos-phorus and sulfur contents set forth above. Generally 3~

the oil compositions of this invention contain at least about 0.01 weight percent of each phosphorus and sulfur.
Typically~ they contain at least about 0.02 percent phos-phorus and about 0.2 percent sulfur.
Other known supplemental additives can be included in the oil composi~ions of this invention. For example, it is often desirable to include an anti-foam agent such as a silicone fluid of high viscosity such as a dimethyl silicone polymer having a kinematic viscosity at 25C. of about 1000 10 cPs. A typical anti-foam agent is p-epared by diluting about 10 parts by weight of dimethyl silicone polymer with kerosene to provide 100 parts per weight solution. From 0.005 to 0.5 percent by weight of this concentrate is then employed in the finished oil composition. Anti-oxidants may 15 also be used in the oil compositions of this inven~ion.
Amines often serve this function, particularly aryl-sub-stituted amines such as phenyl naphthyl amines, phenylene diamines, and the like. They are typically used in con-centrations ranging from 0.1 to 2~5 weight percent. Vis-20 cosity index improvers may be used in the compositions ofthis invention. Often such materials are high molecular weight polymers ofj for example, acrylic esters such as the material sold by Rohm and Haas Company of Philadelphia, Pennsylvania under the trade name "ACRY~OID". Generally, 25 relatively low amounts of such synthetic high molecular weight visc05ity improvers can be used such as about 0.01 to about 2.5 percent (by weight) high molecular weight viscosity index improver. Hydrocarbyl viscosity index improvers can be also used such as hydrocarbyl polymers, 30 polyisobutene polymers are particularly well known in this regard as viscosity index improvers, particularly those having molecular weights ranging from 50,000 to 250,000 and higher. ~ypically these are used in the amount of about 2.5 to 25 weight percent, sometimes about 4-20 percent, of the 35 overall oil composition.

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Other additives known to the art can also be included in the oil compositions of this invention so long as ~heir cumulative effect is not such to exceed the ~is-cosity or elemental parameters set forth above.
EX~MPLES
Example 1 "
A transmission oil for manual transmissions is blended from 100 parts per weight synthetic olefin oligomer prepared by cationic polymerization of a normal olefin frac-10 tion having a mean carbon atom count of 10, 8.25 parts of a commercially available extreme pressure agent comprising a mixture of aliphatic amine salts of sulfur/oxygen-containing alkyl phosphoric acids and 0.25 parts by weight Acryloid 150. Blending is carried out to provide a homogeneous 15 dispersion.
Example 2 A synthetic oil suitable for use as a manual transmission fluid is blended using the formulation of Example 1 with the addition of 15 parts by weight of a 20 poly(isobutene) V.I. improver.
Example 3 An oil for manual transmissions based on synthetic lubricants is prepared by blending a mixed-base oil and the E.P. agent and foam inhibitor descxibed in Example 1 in the 25 amounts set forth in Example 1. The mixed-base oil com-prises 55 percent by weigh~ of the synthetic oligomer des-cribed in Example 1 and 45 percent by waight of a synthetic olefin oligomer oil ha~ing a viscosity of 40 cSt at 100C.
available from Uniroyal, Inc.,Uniroyal Chemical Division of 30 Naugatuck, Conn., U.S.A., under the trade name PAO 40.
The oil of Example 1 is placed as a transmission oil in a 5-speed manual transmission installed in a 1980 Ford Mustang automobile equipped with a 2-3 liter engine.
It is found to lubricate the transmission satisfactorily 35 under both cold and hot operating conditions.

As previously stated, this invention also provides a method of operating an automatic automotive transmission which comprises lubricating the transmission with an auto-matic transmission fluid composition comprising:
tA-l) A base oil comprising a major amount of a syn-thetic, liquid, hydrocarbon-based olefin oligomer, and (B) A minor amount of extreme pressure agent con-taining phosphorus and sulfur.
The description of oils used in the automatic lO transmission fluids of this invention as "base oils" (A-l) reflects the fact that the oil compositions are based upon them; in other words, the oils are the predominant oils in the lubricating oil composition. These oil compositions contain more than 5Q percent by weight, generally more than 15 about 70 percent, often as much as 85 or 95 percent syn-thetic olefin oligomer oil. These olefin oligomer oils can be admixed with various other types of oils either hydro-carbyl or not (as long as the other descriptive parameters are met). Specific examples include alkylated benzene oils, 20 carboxylate ester oils, silicate oils, polyglycol~based oils, and the like. Many such useful synthetic oils are known to the art. The synthetic olefin oligomer oils of this invention can also be combined with various natural oils such as those derived from mineral sources (petroleum, 25 coal, shale, etc.) as well as other sources such as vege-tables and animals. Typically, however, the automatic transmission fluid compositions of the present invention contain base oils consisting essentially of synthetic olefin oligomer oil.
The synthetic oligomer oils of the present in-vention are liquid at room temperature and exhibit fluid flow at this temperature. Furthermore, their viscosity properties are such that at -40C. the viscosity of the automatic transmission fluid compositions based upon them as 35 measured by ASTM Method D-2983 are found to be less than about 50,000 cPs at this temperature. This can be accom-plished by having an olefin oligomer oil of the proper `

3~ ~ 5 viscosity in i~self or by blending an olefin oligomer with one or more othex oils as indicated above to provide the desired viscosity properties~
The automatic transmission fluid compositions of the present invention have a viscosity of less than about 50,000 cPs at -40C. as measured by ASTM Method D-2983.
Often they have a viscosity less than about 12,000 cPs at -40C. Typically, the fluids of this invention have vis-cosities of less than about 20 centistokes at 100C. More 10 usually, the fluid composition's viscosity is less than about 12 centistokes at 100C~ Typically, the automatic transmission fluid composition's viscosity is less than about 8 centistokes at 100C.
The synthetic olefin oligomer oils upon which the 15 automatic transmission fluid compositions of this invention are based are hydrocarbon-based in nature. The term "hydro-carbon-based", when used herein, denotes a compound, compo-sition and so forth having predominantly hydrocarbon charac-ter within the context of the invention. Such materials 20 include the following:
l. Hydrocarbon compounds, compositions, etc., that is, aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl or cycloalkenyl), aromatic, aliphatic- ar alicyclic-subst.ituted aromatic, aromatic-substituted ali-25 phatic and alicyclic materials, and the like.
2. Substituted hydrocarbon compounds, compo-sitions, etc., materials containing non-hydrocarbon sub stituents which, in the context of this invention, do not alter the predominantly hydrocarbon character of the ma-30 terial. Those skilled in the art will be aware of suitablesubstituents; examples are:
halo, nitro, cyano, RO-, R -, RO -, o R2N-, R2NC-, (R being hydrogen or a hydrocarbon radical).
3. Hetero compounds, compositions, etc.; that 3~ S

is, materials which, while predominantly hydrocarbon in character within the contex~ of this invention, contain atoms other than carbon present in a chain or ring otherwise composed of carbon ~toms. Suitable hetero atoms will be apparent to those skilled in the art and include, for example, oxygen and nitrogen.
In general, no more than about three substituents or hetero atoms, and preferably no more than one, will be present for each 10 carbon a~oms in the hydrocarbon-based 10 compound, composition or material.
Terms such as "alkyl-based" and the like have meanings analogous to the above with respect to alkyl materials and the like.
Preferably, the synthetic olefin oligomer oils in 15 the automatic trans~ission fluid compositions of ~his invention are purely hydrocarbyl. Usually this means that the olefins used to make them are also purely hydrocarbyl in character.
The ~ynthetic oligomeric oils of this invention 20 are made by oligomarizing one or more olefins to make a product which can serve as the base oil itself or in ad-mixture as described above. Generally, these olefins will be mono-olefins although in certain cases varying amounts of di-olefins, particularly non-conjugated di-olefins, can be 25 used as long as the products provide oils having the appro-priate properties. Similarly, these olefins are usually aliphatic in nature and therefore do not contain aromatic groups although relatively small amounts of aromatic-con-taining olefins can be used, particularly in admixture. The 30 olefins used to produce the oligomeric base oils of this invention can have the olefinic (double) bond located in any position within their structure. Often a mixture is used having a statistical distribution of double bonds located in all possible positions. Typically, however, alpha-olefins 35 (l-olefins) are used exclusively or at least predominantly.
Usually, these alpha-olefins and indeed, the other internal 3~:15 olefins are normal; that is, they are straight-chained compounds having no branching. Bxanch-chain olefins, particularly in admixture, can also be used. Usually, the olefins used in producing the oligomers used as base oils for the automatic transmission fluid compositions of this invention contain about 6- 18 carbon atoms, usually about 8-12 carbon atoms. A mixture having a mean carbon content of about 10 carbon atoms (calculated on weight basis) can be used. Usually this fraction is purely hydrocarbyl in nature. As noted above, it is hydrocarbon-based in any event.

Preparation of the synthetic olefin oligomers used as base oils in the automatic transmission fluid compositions of the present invention can be carried out by many techniques known to those of skill in the art. Among these techniques is cationic polymerization of the aforedescribed olefin mixtures, particularly the normal alpha-olefin mixtures of about 6-18 carbon atoms. Such cationic oligomerizations are usually catalyzed by Lewis acids. A number of such processes have been described; see, for example, U.S. Patents 3,149,178 (to 20 Hamilton et al.); 3,376,360 (to Feezel); 3,382,291 (to Brennan);
3,576,898 (to Blake et al.); and 3,763,244 (to Shubkin).

The synthetic olefin oligomers used as base oils in the automatic transmission fluid compositions of the present inventian are either hydrogenated oligomers or unhydrogenated oligomers. Methods for hydrogenating such oligomers are known.
See, for example, the aforementioned '178 patent, as well as U.S. Patents 3,682,823 (to Smith et al.); 3,780,128 (to Shubkin); 3,808,134 (to Romine); 4,032,591 ~to Cupples et al.);

4,167,534 (to Petrillo et al.); 4,176,045 (to Coant); and 30 4,175,047 (to Schick). A base oil composed of only hydrogenated ~7 ~ 3 or only unhydrogenated oligomers can be used in the oil compositions of this invention. Alternatively, base oils comprised of mixtures of both types of oligomers, that is, hydrogenated/unhydrogenated, either by themselves or in admixture with other materials as indicated above can be used.
Typically, however, the mixture is either only hydrogenated oligomers or of only unhydrogenated oligomers.

AS indicated above, the base oils used in the automatic transmission fluid compositions of this invention include olefinic oligomers in mixture with other materials such as those described above. Often, however, the base oil contains no more than about 10 percent by weight of natural or non-olefin derived synthetic oil and, in many cases consists essentially of synthetic, liquid hydrocarbon-based olefin oligomer. Typically, such oligomers are purely hydrocarbyl and derived from normal alpha-olefins having about 6-18 carbon atoms, often from normal alpha-olefins having a mean ~by weight) carbon content of about 10 carbon atoms.

Extreme pressure or l'E.P." additives and agents (B) are well known to those of skill in the art. They are also often referred to as load-carrying agents. These materials are chemicals which are added to lubricatiny oils to prevent metal-to-metal contact between relatively moving surfaces during lubrication. Such metal-to-metal contact can lead to wear and ultimately catastrophic destruction of metal parts.
Descriptions of extreme pressure agents are available in the prior art. Seer for example, "Lubricant Additives" by Smalheer, and Kennedy, Lezius-~iles Co., Cleveland, Ohio (1967), pages 9-11, particularlyl and U.S. Patent 4,162,985.

~, ' s The extreme pressure agents used in the automa~ic transmission fluid compositions of the present invention contain phosphorus and sulfur, usually in chemically com-bined form. This does not mean that a single agent (or even a single compound in a given agent) contains both phosphorus and sulfur though this may be the case. It is sufficient that at least a phosphorus-containing and a second sulfur-containing agent, or co~pound be present. It is sometimes the case that both elements are present in a sing~e agent or 10 compound. In other cases, one agent or compound may contain both and the o~her but one. In addition, supplemental agents containing neither phosphorus or sulfur can be present. It is only necessary that at least one E.P. agent or combination of E.P. agents containing sulfur and phos-15 phorus be present.
Extreme pressure agents are usually organic com-pounds in the sense that they contain at least one organic moiety within their structure. They may be metal salts o~
organo acids in which case there are both inorganic and 20 organic portions to the molecule. In other instances, they may be wholly organic and not contain any inorganic or metallic portion. Among the more typical extreme pressure agents for use in the oil compositions of this invention are organic sulides and polysulfides, such as benzyl~disulfide, 25 bis-(chlorobenzyl) disulfide, dibutyltetrasulfide, sul-furized sperm oil, sulfurized methyl ester of oleic acid, sulfurized terpene, sulfurized Diels Alder adducts, hydroxy thioethers, and the like7 phosphosulfurized hydrocarbons, such as the reaction product of phosphorus sulfide with 30 turpentine or methyl oleate; phosphorus esters such as dihydrocarbon and trihydrocarbon phosphites, i.e., dibutyl phosphite, diheptyl phosphi~e, dicyclohexylphosphite, dipentyl phenyl phosphite, tridecyl phosphite, distearyl phosphite, and polypropylene substituted phenol phosphite;

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metal thiocarbamates, such as zinc dioctylkhiocarbamates and barium heptylphenyl dithiocarbamate; and Group II metal salts of phosphorodithioic acids such as zinc dicyclohexylphosphoro-dithioate and the zinc salts of phosphorodithioic acid.
Supplemental extreme pressure agents containing neither phosphorus nor sulfur include chlorinated paraffin waxes, lead soaps such as lead naphthanate, and other materials known to the art. A number of E.P. agents have been described in the art, including those noted above and still other types; see, for example, the disclosure in "Lubricant Additives - Recent Developments" by M.W. Ranney, Noyes Data Corporation, New Jersey (1378), particularly pages 165-204.

Extreme pressure agents used in the automatic transmission fluid compositions of this invention are often formulated in additive concentrates or packages and as such may contain one or more inert solvent/diluents which in turn may constitute one or more oils. Such oils are not considered to be base oils in the sense of this invention and in view of their relatively low concentrate in the overall oil compositions of this invention they are not included in the term "base oils" as used herein.

The extreme pressure agent or agents used in the automatic transmission fluid compositions of this invention are employed in a concentration so as to yield an oil composition having less than about 0.10 weight percent phosphorus and less than about 1.5 weight percent sulfur. Typically, they contain less than 0.05 percent phosphorus and less than 1.0 percent sulfur, and since the phosphorus and sulfur content of the agent may in itself be a relatively low percentage of its overall weight, this means that the extreme pressure agent can be used in amounts ranging between, for example, about 0.25-10.0 weight percent phosphorus-containing agent and about 0.25-20~0 weight percent s3~5 sulfur-containing agent. Usually~ however, the extreme pressure agent or agents will be used in an amount between, for example, about 0.5-10 weight percent of each agent. If the agent used contains both phosphorus and sulfur it is used in concentrations to produce automatic transmission fluid compositions having phosphorus and sulfur contents set forth above. Generally, the automatic transmission fluid compositions of this invention contain at least about 0.01 weight percent of each phosphorus and sulfur. Typically, 10 they conkain at least about 0.02 percent phosphoru~ and about 0.2 percent sulfur.
In addition to the base oil (A-l) and the extreme pressure agent (B) the automatic transmission fluid compo-sitions of this invention preferably contain one or more 15 lubricating oil dispersants (C). These dispersants are characterized by their ability to suspend and/or disperse sludge, etc. in lubricating compositions and are oil-soluble or stably dispersible in lubricating compositions at the proportions and in the environment employed.
The dispersants, when employed, are used at a level of from a~out 0.01% to about 20% by weiqht or higher, depending on such factors as the nature of the dispersant and nature of the lubricating oil. Usually, suah disper-sants are employed at a level of from about 0.1~ to about 25 15% by weight. These percentages refer to the percent by weight based on the total weight of the final lubricating oil composition.
The terminology l'dispersant" as used in the present specification and claims refers to those materials 30 selected from the group consisting of (C-l) high molecular weight acylated nitrogen-based dispersants; (C-2) high molecular weight ester-based dispersants; (C-3) high molec~
ular weight Mannich-based dispersants; (C-4) high molecular weight hydrocarbyl amine-based dispersants; (C-5) post-35 treated products of one or more of (C 1) through (C-4); (C-6) interpolymeric dispersants having repeating pendant 3~1L5 groups of up to about 24 carbon atoms; and (C-7) mixtures of two or more of any of the dispersants included in (C-l~ through (C-6). Preparation and use of these dispersants are generally known in the art.

(C-l) High molecular weight acylated nitrogen-based dispersants.

These dispersants can be generally characterized as materials having at least one high molecular weight oil-solubiliæing group which is a hydrocarbon-based group ordinarily having at least about 30 aliphatic carbon atoms and further characterized as having at least one nitrogen atom directly attached to a polar group.

The dispersants of Class (C-l) are usually complex mixtures whose precise composition is not readily identifiable.
Accordingly, such dispersants are frequently described in terms of a method of preparation. Examples of dispersants of Class (C-l) are described in many U.S. patents including:
3,172,892 3,341,542 3,630,904 3,215,707 3,444,170 3,632,511 3,219,666 3,448,048 3,787,374 3,272,746 3,454,607 3,804,763 3,316,177 3,541,012 3,836,470 A convenient route in the preparation of dispersants of Class (C-l) comprises the reaction of a "carboxylic acid acylating agent'l with a nitrogen-containing compound such as an amine, either alone, or in further combination with an organic hydroxy compound. As used herein, "carboxylic acid acylating agent" describes an acid or derivatives thereof such as an anhydride, acid halide, ester, amide, imide or amidine or -the like. These carboxylic acid acylating agents have been described previously in detail. They include monocarboxylic acid acylating agents or polycarboxylic acid acylating agents.

;9~S

Monocarboxylic and polycarboxylic acid acyla~ing ayents have been described, for example, in U.S. Patents 3,087,936;
3,163,603; 3,172,892; 3,189,544; 3,219,666; 3,272,746;
3,288,714; 3,306,907; 3,331,776; 3,340,281; 3,341,542;
3,346,354; 3,381,022 and 3,755,169. Preferred acylating agents usually contain at least about 50 aliphatic carbon atoms in the substituent atoms.

The preparation of typically useful monocarboxylic acid acylating agents is disclosed in U.S. Patent 3,833,624 in columns 2-~, lines 51-73, 1-75, and 1-35, respectively. U.S.
Patent 3,697,428 discloses polycarboxylic acid acylating agents at columns 2-4, lines 21-72, 1-75 and 1--48, respectively.
Typically, these mono- and polycarboxylic acid acylating agents are conveniently formed from halogenated olefin polymers which are reacted with a,~-unsaturated acids, anhydrides, esters and the like.

Preferred carboxylic acid acylating agents are mono- and dicarboxylic acid acylating agents corresponding to compounds such as hydrocarbon-based substituted acrylic acids and hydrocarbon-based substituted succinic anhydrides or acids.

Useful nitrogen-containing compounds for the preparation of dispersants oE Class (C-l) include mono- and poly-primary or secondary amines, characterized by a radical having the configuration -N-H.

The two remaining valences of the nitrogen atom of the D - N-H radical preferably are satisfied by hydrogen, amino, substituted amino, ox organic radical bonded to said nitrogen atom through a direct carbon-to-nitrogen linkage. These~
amines include ammonia, aliphatic monoamines and polyamines, 3~

hydrazines, aromatic amines, heteroc~clic amines, carboxylic amines, arylene amines, alkylene amines, N-hydroxyalkyl substituted amines and the like. Usually alkylene polyamine containing two or three carbon atoms in the alkylene moieties and from two to ten amino nitrogen atoms having one or two hydrogens per amino nitrogen will be used. T~e ethylene polyamines such as diethylene triamine, tetraethylene polyamine, and mixtures thereof including commercial mixtures containing piperazine, aminoethoxy piperazines, etc., are preferred.

Further examples of such amines appear in U.S. Patent 3,879,308 at columns 10 and 11, lines 11-68 and 1~53~ Other types of amines including specific examples are disclosed, of course, in the above patents relating to high molecular weight acylated nitrogen-based dispersants.

The reaction between the nitrogen-containing compounds (e.g., amine) and the carboxylic acid acylating agent results in the direct attachment of a nitrogen atom to a polar radical derived from the acylating group. The linkage formed between the nitrogen atom and the polar radical may be characterized as an amide, imide, amidine, salt or mixtures of these radicals. The exact relative proportions of these radicals in a particular product may not be precisely known since it depends to a large extent upon the acylating agent, nitrogen compound and the conditions under which the reaction is carried out. For example, a reaction involving an acid or an anhydride with amines at temperatures below about 50C~
will result predominantly in a salt linkage. However, reactions at relatively higher temperatures, e.g., above 80C.
and up to about 250C. or higher results in predominantly an imide, amide, amidine linkage or mixtures thereof.

'3~
- 2~ -Generally, however, the dispersants of Class (C-l~ may be characterized in that they contain at least one acyl, acyloxy or acylimidoyl group having at leastt about 50 carbon atoms which is bonded directly to a nitrogen. The structures of these groups, as defined by the International Union of Pure and Applied Chemistry, are as follows: (R representing a monovalent hydrocarbon-based group or similar graup);

Acyl; R-C-o Il Acyloxy;R-C-O-N-Acylimidoyl; R-C-The high molecular weight acylated nitrogen-based dispersants of Class (C-l) can also contain other polar groups.
For example, the carboxylic acid acylating agent can be reacted with a polyhydric alcohol and thereafter be reacted with an amine. Such a high molecular weight acylated nitrogen-based dispersant is described in U.S. Patent 3,836,470.
Alternatively, for example, a polycarboxylic acid acylating agent can be reacted with, for example, an alkylene polyamine, and the resulting reaction product contacted with certain polyhydric alcohols. Such acylated nitrogen-based dispersants are described in U.S. Patent 3,632,511.

For a better understanding of the high molecular weight acylated nitrogen-based dispersants, several specific examples of such dispersants are set forth in Table I.

.

:~.l.t~ 5 ~: h o u~ o C~ o o o o o o o o o o ~E~
.
U~
H er ~r ~ O O O O C~
H O O O r-J ~1 ~J r-l O ~1 0 :~
P~ ~ ~1 , a~
~1 0 H O O O
H O ,~ ~ ~1 a) ~1~ o ~ X X ~ u~ ~
O-- ~ X ~ R~ $
E~~ ~ ~ ~ ~ ~ ' ~ ~ O X ~
O t~ h ~ ~1 a) ~ o O ~ ~1 O
~ O ~,~ a, 5~ ~1 0 ~1 Z C) ~ ~ X ~
O 0 ~1 0 ~J oa) rl ~ rl I ~1 0 rl ~ 1) 0 ~1 0 :4 V t~ 1 ~ Z
_ ~

a) 'tCr H~) `I O ~ t~ lc O
_ "a O ~ Q~ 3 a) 3 V ~ -'1 !:~ ~1 U h O a) U
o o ~-~ n U ~ X X ~
Q V
V O ,1 0 ~ k o a3 ~. ~. a~, o O
X ~ ~ ~ a) o ~1 O ~ ~ ~ Xa ~ ~ ~ co X X X X X a5~ ~ ~H a h ~ R o ~ (d R ~ ~d Q
~ v o ~ v ~ ~n x o ~ x o ~ Ul X O ~
C~ ~ U~ ~-rl ~ ~ Ul O ~ U~ O ~ O
~ ,1 Q rl ,~ ,1 ~ ~

O ,Q ~ S~ 1 0 U~ rl O ~ r~ O U~ h ~ V U~ ~ -r~ a~
~ æ
I ~~ r~ ~ In ~ r~ o~ ~o ~c 3~S

(C-2) High molecular weight ester-based dispersants.

The high molecular weight ester-based dispersants can be generally characterized as containing at least one hydrocarbon-based group having at least about 30 aliphatic carbon atoms and further characterized as having at least one ester group. For convenience of description, these high molecular weight ester-based dispersants of Class (C-2) are substantially free of groups formed by the reaction of an amino nitrogen with an acylating agent inasmuch as such dispersants are included in Class (C-l) above.

The dispersants of Class (C-2) are well known in the art. Exemplary of such dispersants are those disclosed in the following U.S. patents:
3,381,022 3,697,428 3,522,179 3,833,624 3,542,678 3,838,052 3,542,680 3,879,308 3,576,743 The dispersants of Class (C-2) are ordinarily complex mixtures of ester-containing materials whose precise composition and/or structure is not often readily identifiable.
Accordingly, such dispersants of Class (C-2) are re~uently described in terms of their method of preparation.

The dispersants of Class (C-2) are generally prepared by the reaction of a carboxylic acid acylating agent as described above in Class (C-l) with an organic mono- or polyhydroxy compound. Moreover~ included with the dispersants of Class (C-2) are those materials prepared by the reaction of a carbo~ylic acid acylating agent with a mono-` 30 or polyhydroxy compound which is thereafter again reacted : ,;

with a carboxylic acid acylating agent. Typically useful organic mono- and polyhydroxy compounds are quite diverse in structure.

The hydroxy compounds may be aliphatic monohydric and polyhydric alcohols and aromatic hydroxy compounds such as phenols and naphthols. The monohydric alcohols include methanol, ethanol, isooctanol, dodecanol, cyclohexanol, eicosanol, neopentyl alcohol, isobutyl alcohol, and the like. The polyhydric alcohols will normally contain from 2 to about 10 hydroxy radicals. These polyhydric alcohols are illustrated by, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and other alkylene glycols in which the alkylene radical contains from about 2 to about 8 carbon atoms. Other useful polyhydric alcohols include glycerol, monooleate of glycerol, monostearate of glycerol, monomethyl ether of glycerol, pentaerythritol, 9,10-dihydroxy stearic acid, sorbitol, mannitol, 1,3-cyclohexanediol, and the like. Carbohydrates with free hydroxy groups such as sugars, starches, and celluloses, are useful in the preparation of a high molecular weight ester-based dispersants of Class (C-2). These carbohydrates may be exemplified by glucose, fructuse, sucrose, mannose, and galactose.

Typically useful mono- and polyhydroxy aromatic compounds include those wherein the aromatic nucleus of the aromatic compound is a benzene ring or an aromatic condensed hydrocarbon ring such as naphthalene. Monohydroxy and polyhydroxy phenols and naphthols are especially useful hydroxy aromatic compounds.
Exemplary of such mono- and polyhydroxy aromatic compounds are those disclosed in U.S. Patent 3,542,680, which discloses of high molecular weight ester-based dispersants utilizing mono-and polyhydroxy aromatic compounds.

S
-2~-Preferred organic hydroxy compounds include those which are polyhydric aliphatic alcohols containing up to 10 carbon atoms. Within this class are an especially preferred class o~ polyhydric alcohols including polyhydric alkanols containing 3 to 10, and more preferably 3 to 6 carbon atoms, and hav.ing at least 3 hydroxyl groups. Such alcohols are exemplified by glycerol; 2-hydroxymethyl-2-methyl-1,3-propanediol ~i.e., TME), 2-hydroxymethyl-2-ethyl-1,3-pro-panediol (i.e., TMP); 1,2,4-butanetriol, 1,2,6-hexanetriol;
1,2,3-pentanetriol; and the like. For a better under-standing of these high molecular weight ester-based dis-persants, specific examples of such dispersants are set forth in Table II.

a~
o ~ ~ o o r-i ~ ' O C~l O
) ~ J N
h o l l l ~a a) .,~ O ~ o P~E3 r--Ir--I r--1 r--I

O O
O ~
O
~01 C U r~l e 05 (~J X Il CJ~ r--~1 0 00 61 r--¦
r-~ ~ ~ 11'1 Lf) ~) ~ 1~1 C) ~
3 ::~/ r-~ ~

~1 1~1 0 O a ~ Q) _ ,~ r~
O r~ 11 ~r-l O ~ >1 I r~ X
r-l ~ O O
~ r~
H ¦ ~1 S ~ O

rT~r--l X ~ r-¦ ~ (I) l¢U ~ IJ h I ~ ~ r-l r-E~~D E ~ o p~

~n r~ r~
r~ O ~J r-l ~1 ~\ ~c O ~ ~J r--l tn ~ ~ r-l O ~ 3 ~ r ~J 3 E~ ~ r ~ v au ~ ~ 3 r~l r l r~l ~.) ~ Q a.)r~l c) ~ r--l ~.) ~I Q a) r J E3 (L~ o r^~ o r~ h r-l ~ h r-l O ~ r~ o ~ ~ ) r~ r l (~
.) c~ ~ r-H-I td ~ (u r-l h ~ r-l h ~ ~-r-l a) ri h r~i ,~ h ~r~
r~ r~ S v t.~ t~ r~
~r~ (J~ 0 ~ ) a) r--l ~ QO ~ ~
~r-l ~~ h ~r~ r7~ 0 ~r~ ~ r h 0 x ~ ~ O q~ ~ O ~ ~ o a) u Q 0 O ~ 0 ~ .Q ~0 h rO td Q ~:J 0 h ~ o r--l ~1) O ~.) O r~l ~r-l ~ r--l O r~l ~ ~4 0 r--l rl ~ r-l 0 0 C) U~ h 11~ ~r-l U~ tn h ~r-l 0 h C ) td .~1 .~ J ~J r-l r~l ~1 ~ r~ (J) r~ ~r-l ~r-¦ ~) ~ S_; ~ O
~ 0 '?1 ~ r~ ~>1 O
r--l O a) r~ 1 r--l O ,~ r--t r~ r--l O ~r-l ~ r--¦ r--l O ,~ r--l r~
O R $1 O O O R ~ ~ ~ O Q ~1 0 0 0 R ~
0 0 ~ (d p,0 r~ 4 0 ~ 0 . R~
~ Z
r~l Id r _~ r--l r--I

~ 1~9~5 (C-3) High molecular weight Mannich-based dispersants.

The dispersants of Class (C-3) can be characterized as reaction products of alkyl phenols in which the alkyl group contains at least about 30 carbon atoms with lower aliphatic aldehydes (especially formaldehyde) and amines (especially polyalkylene polyamines). These dispersants are well known in the art and are described in the following U.S. patentsu 3,169,516 3,725,277 3,413,347 3,736,357 3,448,047 3,772,359 3,591,598 3,798,165 3,649,229 3,872,019 High molecular weight Mannich-based dispersants are often complex mixtures whose precise composition is not readily identifiable. Accordingly, these materials are frequently described in terms of their method of preparation.
Thus, for example, a hydroxy aromatic compound is reacted with a carbonyl compound and a compound containing at least one primary or secondary amino group to form the dispersants within Class (C-3).

Representative high molecular weight alkyl-substituted phenols include polypropylene-substituted phenol, polybutylene-substituted phenol, polyamylene-substituted phenol and similarly substituted phenols. In pIace of the phenol, high molecular weight alkyl-substituted compounds of resorcinols, hydroquinones, catechols, cresols, xylenols and the like, can be employed.

Typical aldehydes are the aliphatic aldehydes such as formaldehyde, acetaldehyde, and ~-hydroxbutraldehyde;
aromatic aldehyde, such as benzaldehyde, heterocyclic aldehydes, such as furfural; etc. Preferred aldehydes are, however, aliphatic aldehydes with formaldehyde being particularly preferred.

s Useful amines include those which contain an amino group characterized by the presence of at least one active hydrogen atom. Typical amines are the alkylene polyamines such as ethylene diamine, propylene diamine, polyalkylene polyamines such as diethylene triamine, triethylene tetramines; hydroxy amines such as hydroxy-substituted alkylene amines and polyalkylene polyamines, and the aromatic amines such as o-, m-, and p-phenylamines. Heterocyclic amines which are suitable are those characterized by attachment of a hydrogen atom to a nitrogen atom in hetero-cyclic group. Representative of these amines are morpholine, thiomorpholine, imadazoline, and piperidine.

Typical specific examples of the dispersants of Class (C-3) are found in the above-cited patents disclosing Mannich-base dispersants.

(C-4) Hydrocarbyl amine-based dispersants.

The dispersants of Class (C-4) can be generally characterized as high molecular weight materials having at least one amino moiety attached to a hydrocarbyl group of at least about 30 carbon atoms. Mineral acid salts of these amines are also included in Class (C-4) as, for example, those dispersants in U.S. 3,573,010. These dispersants are well known in the art. The following U.S. patents are exemplary of the preparation and use of such dispersants:
3,275,554 3,671,511 3,373,112 3,755,433 3,438,757 3,822,209 3,454,555 3,869,514 3,565,804 3,873,460 3,573,010 The dispersants of Class (C-4~ can be readily prepared by combining an aliphatic or alicyclic halide with the desired amine in appropriate molar proportions. The halide can be derived from a hydrocarbon by halogenation and the t3~
-32~

hydrocarbon is usually derived from the polymerizakion of olefins con~aining from about 2 to 6 carbon atoms. Typical olefins which find use are propylene, isobutylene, l-pen-tene, and 4-methyl-1-pentene. Usually preferred olefins are propylene and isobutylene.
T~pical hydrocarbyl amine dispersants conform for tha most part to the formula - ~CH2)2 -N(-WN-) t-WN tCH2j2' ~' - Rc H3+a~C

wherein W is alkylene from 2 to 6 carbon atoms; a is an 10 integer from 0 to 10; b is an integer of 0 or 1; a ~ 2b is an integer from 1 to 10; c is an integer in a range from 1 to 5 and averages in the range of 1-4 over the entire com-po~ition and is less than the number of amine nitrogens in the molecule; and R5 is a hydrocarbyl group of at least 15 about 30, preferably 60 to 200 aliphatic carbon atoms.
Thus, these high molecular weight hydrocarbyl amines include mono- and polyamines substituted with at least one high molecular weight hydrocarbyl group. The amines of Class ~C-4) can be hydroxy-substituted amines a~ well.
(C-5) Post-treated produ~ts of Classes (C-l), (C~
2), (C 3) and (C-4).
The dispersants of Classes (C-l)-(C-4) can be post-treated with such reagents as urea, thiourea, carbon disulfide, aldehyde, ketones, anhydrides, nitriles, epoxides, 25 boron compounds, metal salts, phosphorus compounds and the like to form oil-soluble or stably disp~rsible dispersants.
Exemplary materials of this kind are described i~ the following U.S. patents:
3,036,0~3 3,281,428 3,502,677 3,639,242 30 3,087,936 3,282,955 3,513,093 3,649,229 3,200,107 3,367,943 3 t 533,945 3,697,574 3,216,936 3,403,102 3,539,633 3,702,757 3,Z54,025 3,455,831 3,579,450 3,703,536 3,256,185 3,455,832 3,591,59~ 3,704,308 35 3,27~,550 3,493,520 3,600,372 3,912,641 ~l$~,13~

(C-6) Interpolymeric dispersants having repeating pendant groups of up to about 24 car~on atoms.

These dispersants of Class (C-6) can be characterized as materials which normally can serve to improve the viscosity index of lubricating compositions and also function as dispersants.
The repeating pendant groups are normally oil-solubilizing groups (i.e., function to enhance the solubility of the interpolymeric dispersant in oil). `~

The interpolymeric dispersants are generally used in combination with any of the dispersants of Classes (C-l)-(C-5) above, but may be used alone in the lubricating compositions without other dispersants. The interpolymeric dispersants are distinguished from the dispersants of Classes (C-l)-(C-5) by the repeating character of the pendant groups. The interpolymeric dispersants also normally do not contain aliphatic carbon chains of over about 24 carbom atoms. Many examples of these materials are known to those in the art. Some of these examples are in U.S. PatentsO
3,329,658 3,666,730 3,449,250 3,687,849 3,519,565 3,702,300 3,9331761 which disclose the preparation and use of interpolymeric dispersants haviny repeating pendant groups of up to about 25 carbon atoms. A preferred type interpolymeric dispersant is that type of dispersant disclosed in U.S. Patent 3,702,300 (above) which is a nitrogen-containing mixed alkyl ester of a styrene-maleic anhydride copolymer having mixed-ester radicals of from 1 to 24 carbon atoms.

(C-7) Mixtures of dispersants of Classes (C-l)-(C-6).

Mixtures of one or more dispersants from those within any of the Classes (C-l) through ~C-6) can also be employed, especially and preferably combinations of boron post~treated dispersants with other dispersants.

In a preferred aspect of this invention the automatic transmission fluid compositions comprise (A-l) and (B) in combination with a boron-containing dispersant (C-4). Boron-containing dispersants have been disclosed in the prior art as being useful in lubricating compositions. Typical of these boron-containing dispersants are those disclosed in the following U.S. patents:
U.S. Patents - Dispersant type 3,000,916 borated, acylated nitrogen-based 3,087,936 borated, acylated nitrogen-based 3,254,025 borated, acylated nitrogen-based 3,281,428 borated, acylated nitrogen-based 3,282,955 borated, acylated nitrogen-based 3,306,908 borated, acylated nitrogen-based 3,344,069 borated, acylated nitrogen-based 3,449,362 borated, acylated nitrogen-based 3,666,662 borated, acylated ni-trogen-based 3,533,945 borated, ester-based 3,442,808 borated, Mannich based 3,539,633 borated, Mannich-based 3,697,574 borated, Mannich-based 3,703,536 borated, Mannich-based 3,704,308 borated, Mannich-based 3,751,365 borated, Mannich-based 3,658,836 borated, hydrocarbyl amine-based These patents disclose the preparation and use o~ boron post-treated dispersants.

Particularly preferred of the boron-containing dispersants are the boron post-treated acylated nitrogen-based dispersants described in U.~. Patents 3,087,936 and 3,254,025. These dispersants are nitrogen and boron-con- .....

9~5 taining compositions obtained by treating an acylated nitrogen-based dispersant ~see the description of Class (C-l) above) characterized by the presence within its struc-ture of ~a) a hydrocar~on-based substituted succinic radical S selected from the class consis~ing of succinoyl, succin-imidoyl, succinoyloxy radi.cals wherein the hydrocarbon-based substituent contains at least about 50 aliphatic carbon atoms and (b) a nitrogen-containing group characterized by a nitrogen atom attached directly to the succinic radical, 10 with a boron compound selected from the group consisting of boron oxide, boron halide, boron acids, and esters of boron acids in an amount to provide from about 0.1 atomic pro-portion of boron for each mole of the acylated nitrogen-based dispe~ant to about 10 atomic proportions of boron for 15 each atomic proporti~n of nitrogen of the acylated nitrogen-based dispersant.
Especially preferred boron-containing dispersants are prepared by forming an acylated nitrogen-based inter-mediate by the reaction at a temperature within the range 20 from about 80~C. to about 250C., of a substantially alipha-tic olefin polymer-substituted succinic acid acylating agent having at least about 50 aliphatic carbon atoms in the polymer substituent with at least about one-half of an amine equivalent for each equivalent of the acylating compound 25 used, selected from the group consisting o~ alkylene amines and hydroxy-substituted alkylene amines, and reacting, at a temperature between about 50C. and about 250C., the high molecular weight acylated nitrogen intermediate with a boron compound selected from the group consisting of boron oxide, 30 boron halide, boron acids, and esters of boron acids in an amount to provide a boron content as specified hereinabove.
Particularly preferred among this subclass of boron-con-taining dispersants are those where the hydrocarbon sub-stituents of (a) is a polyisobutene having a number average ;'3~5 molecular weight of about 700 to about 5,000 as determined by vapor pressure osmometry.

The automatic transmission fluid compositions oE this invention can also contain other lubricant additives known in the prior art. A brief survey of conventional additives for lubricating compositions is contained in the publications LUBRICANT ADDITIV~S, by C.V. Smalheer and R. Kennedy Smith, published by the Lezius-Hiles Company, Cleveland, Ohio (1967) and LUBRICA~T ADDITIVES, BY M.W. Ranney, published by Noyes Data Corporation, Parkridge, New Jersey (1973). Reference may be made to these publications to establish the state of the art in regard to identifying both general and specific types of other additives which can be used in conjunction with the additives of the present invention.

In general, these additional additives include (besides the hereinbefore mentioned extreme pressure agents and dispersants) such additive types as ash-containing detergents, viscosity index improvers, pour point depressants, anti-foam agents, anti-wear agents, rust-inhibiting agents, oxidation inhibitors, corrosion inhibitors, seal swell agents and friction modifiers.

The ash-containing detergents are well known. They comprise basic alkali or alkaline earth metal salts of sulfonic acids, carboxylic acids or organo-phosphorus-containing acids. The most commonly used salts of these acids are sodium, potassium, lithium, calcium, magnesium, strontium, and barium salts are used most extensively as compared to the others. The "basic salts"
are those metal salts known to the art where the metal is present in a stoichiometrically larger amount than necessary to neutralize the acid. Potassium- and barium-overbased petrosulfonic acids are typical examples of such basic detergent ....

salts. Ash-containing detergents can replace the abo~e-described dispersants in whole or in part in the lubricating compositions.
Pour point depressing agents are illustrated by the polymers of ethylene, propylene, isobutylene, and poly(alkyl methacrylic). Antifoam agents include silicones, polymeric alkyl thiooxane, poly(alkyl methacrylates), terpoly-mers of diacetone acrylamide and alkyl acrylates or meth-acrylates, and the condensation products of alkyl phenol 10 with formaldehyde and an amine.
Viscosity index improvers include polymerized and copolymerized alkyl methacrylates and mixed esters of styrene-maleic anhydride interpolymers reacted with nitrogen-con-taining compounds. Viscosity index improvers may also serve 15 as dispersants in the compositions.
When additional additives are used in the auto-matic transmission fluid compositions herein, they are used in concentrations in which they are normally employed in the art. Thus, they will generally be used in a concentration 20 of from about 0.001% up to about 25% by weight of the total composition, depending, of course, upon the nature of the additive and the nature of the automatic transmission ~luid composition. For example, pour point depressants, viscosity index improving agents, antifoaming agents and the like, are 25 normally emp}oyed in amounts of from about 0.001% to about 10% by weight of the total composition, depending upon the nature and purpose of the particular additive.
The automatic transmission fluid compositions of the present invention may, of course, be prepared by a 30 variety of methods known in the art. One convenient method is to add the additives in the form of a concentrated solu-tion or substantially stable dispersion (i.e., an additive concentrate) to a sufficient amount of the base oil to form the desired final automatic transmission fluid composition.
35 This concentrate contains the additives in proper amounts so as to provide the desired concentration of each additive in . .

the final automattc transmission fluid~composition when added to a predetermined amount of a base oil.
COMPOS ITIONS:
., Example I
A composition suitable for use as an automatic transmission fluid, is prepared, using as the base oil, 65 poly-l-decene having viscosity of 4 centistokes at 100C.
and 35% Of a 200N mineral oil, and as additives, by weight;
4% of a mixed ester of a styrene-maleic anhydride copolymer 10 reacted with a nitrogen-containing compound (prepared as in U.S. Patent 3~702~300); 3.0% Of a commercially available, proprietary seal swell agent; 1% of the reaction product of a polyisobutenyl substituted succinic anhydride, commercial tetraethylene pentamine, and boric acid prepared as in U.S.
15 Patent 312541025; 0.3% Of a commercially available diphenyl-amine based oxidation inhibitor; 0.1% of a dialkyl phos-phite; 0. 5% of a conventional friction modifier based on polyoxyethylene (2) tallowaminei 0. 3 % of a hydroxythioether prepared by reacting propylene oxide and t-dodecylmercaptan 20 (prepared as in U.S. Patent 4r031,023); and 3.0% of the dispersant of Example A-l.
Example II
A composition, suitable as an automatic trans-mission fluid is prepared using as a base oil, poly-l-decene 25 having a viscosity of 6 centistokes at 100C., and as addi-tives, by weight; 2.0% o a seal swell agent; 2.8% of the dispersant of Example A-5; 1.7% of a boron-containing dispersant, the dispersant base first prepared as in Example A-5 and thereafter treated with boric acid; 0.2% of a 30 dialkyl hydrogen phosphite extreme pressure agent; 0.2~ of a commercially available diphenylamine-based antioxidant; 0.3%
of a sulfurized fatty ester-fatty acid-olefin mixture; and 0.5% of a hydroxythioether prepared by reacting propylene oxide and t-dodecylmercaptan tas prepared in U.5. Patent 35 4,031,023).

<~5 Those of ordinary skill in the art to which this invention pertains will, upon consideration of the fore-going, recognize many obvious modiications and equivalents of the invention~ Such modifications and equivalents are intended to be part of this in~ention except to the extent they are excluded by the appended claims.

Claims (18)

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

1. An automatic transmission fluid composition comprising:
(A-1) a base oil comprising a major amount of a synthetic, liquid, unsaturated, hydrocarbon-based olefin oligomer, wherein said oligomers are derived from olefins having about 6-18 carbon atoms;
(B) a minor amount of an extreme pressure agent containing phosphorus and sulfur; and (C) a minor amount of an interpolymer dispersant having repeating pendant groups of up to about 24 carbon atoms;
said automatic transmission fluid composition having a viscosity of less than about 50,000 cPs at -40°C., a phosphorus content of less than about 0.10 weight percent of said composition and a sulfur content of less than about 1.5 weight percent of said composition.

2. A composition according to claim 1 wherein the automatic transmission fluid is a composition having a viscosity of less than about 12,000 cPs at -40°C.

3. A composition according to claim 2 wherein the automatic transmission fluid is a composition having a viscosity of less than about 20 centistokes at 100°C.

4. A composition according to claim 3 wherein the oligomer is derived from purely hydrocarbyl, normal .alpha.-olefins having a mean carbon content of about 10 carbon atoms.

5. A composition according to claim 4 wherein no more than 10%
by weight of the base oil (A-l) is natural or non-olefin derived synthetic oil.

6. A composition according to claim 5 wherein the base oil (A-1) consists essentially of a synthetic, liquid, unsaturated, hydrocarbon-based olefin oligomer.

7. A composition according to claim 1 wherein the automatic transmission fluid is a composition having a phosphorus content of from at least about 0.01 up to less than 0.05 weight percent of said composition and a sulfur content of from at least about 0.01 up to less than 1.0 weight percent of said composition.

8. A composition according to claim 1 wherein the interpolymeric dispersant comprises a nitrogen-containing mixed alkyl ester of a styrene-maleic anhydride copolymer having mixed alkyl ester radicals of from 1 to about 24 carbon atoms.

9. A composition according to claim 3 wherein the interpolymeric dispersant comprises a nitrogen-containing mixed alkyl ester of a styrene-maleic anhydride copolymer having mixed alkyl ester radicals of from 1 to about 24 carbon atoms.

10. A composition according to claim 5 wherein the interpolymeric dispersant comprises a nitrogen-containing mixed alkyl ester of a styrene-maleic anhydride copolymer having mixed alkyl ester radicals of from 1 to about 24 carbon atoms.

11. A composition according to claim 7 wherein the interpolymeric dispersant comprises a nitrogen-containing mixed alkyl ester of a styrene-maleic anhydride copolymer hauing mixed alkyl ester radicals of from 1 to about 24 carbon atoms.

12. A composition according to claim 8 further comprising one or more lubricating oil dispersants selected from the group consisting of high molecular weight acylated nitrogen-based dispersants, high molecular weight ester-based dispersants, high molecular weight Mannich-based dispersants, high molecular weight hydrocarbyl amine-based dispersants, post-treated products of one or more of these dispersants, and mixtures thereof.

13. A composition according to claim 9 further comprising one or more lubricating oil dispersants selected from the group consisting of high molecular weight acylated nitrogen-based dispersants, high molecular weight ester-based dispersants, high molecular weight Mannich-based dispersants, high molecular weight hydrocarbyl amine-based dispersants, post-treated products of one or more of these dispersants, and mixtures thereof.

14. A composition according to claim 10 further comprising one or more lubricating oil dispersants selected from the group consisting of high molecular weight acylated nitrogen-based dispersants, high molecular weight ester-based dispersants, high molecular weight Mannich-based dispersants, high molecular weight hydrocarbyl amine-based dispersants, post-treated products of one or more of these dispersants, and mixtures thereof.

15. A composition according to claim 11 further comprising one or more lubricating oil dispersants selected from the group consisting of high molecular weight acylated nitrogen-based dispersants, high molecular weight ester-based dispersants, high molecular weight Mannich-based dispersants, high molecular weight hydrocarbyl amine-based dispersants, post-treated products of one or more of these dispersants, and mixtures thereof.

16. A method of operating an automatic transmission which comprises lubricating the transmission with the automatic trans-mission fluid composition as claimed in any one of claims 1, 4 or 7.

17. A method of operating an automatic transmission which comprises lubricating the transmission with the automatic transmission fluid composition of claims 9, 11 or 12.

18. A method of operating an automatic transmission which comprises lubricating the transmission with the automatic transmission fluid composition of claims 3, 4 or 5.