JP5541850B2 - Lubricating oil with improved friction stability - Google Patents

Description

The present invention relates to lubricating oils, specifically transmission fluids such as automatic transmission fluid (hereinafter referred to as “ATF”), continuously variable transmission fluid (“CVTF”) and double clutch transmission fluid (“DCTF”). Additives useful to provide excellent frictional properties to the fluid during high speed clutch engagement, and more particularly during high speed clutch engagement Relates to the composition.
Further embodiments include the use of an additive composition in such lubricating oils, a method of imparting frictional stability to the lubricating oil, and additives in lubricating oils for the purpose of improving frictional stability. Use of the composition and other embodiments described below are included.
A transmission to which the present invention is applicable is a transmission that includes a lubricated wet clutch that is used in situations of high energy dissipation. These types apply to clutches in automatic transmissions used to achieve ratio or speed changes; wet start clutches in automatic continuously variable or double clutch transmissions; or torque vectoring or between axles A clutch used in a differential application. These clutches can be characterized as having high energy dissipation in clutch "engagement" or "lock-up" and high differential speed between the two parts of the clutch.
Accordingly, one additional aspect of the present invention relates to a transmission comprising a single plate or multi-plate clutch device lubricated with the transmission fluid of the present invention, in which, during use, the clutch is a high energy I.e. about 500 rpm (revolutions per minute) and in particular under conditions of engagement at the speeds above 500 rpm.

A common goal of automobile manufacturers is to produce vehicles that are more durable and more reliably drive beyond their service life. One aspect of increased durability and reliability is to produce vehicles that require minimal repairs during their service life. The second aspect relates to a vehicle that drives consistently over this “lifetime”. In the case of an automatic transmission, not only does the transmission not function during the life of the vehicle, but its shifting characteristics must not change to a high degree over this period. Since the shifting characteristics of an automatic transmission are highly dependent on the coefficient of friction of ATF, the liquid needs to have a very stable friction performance over time and thus mileage. This aspect of ATF performance is known as friction stability. Many vehicle manufacturers are now focusing on “fill-for-life” automatic transmission fluids; this trend further increases the need for friction stability in ATF, This is because the liquid will no longer be replaced at a service interval of 15,000-50,000 miles.
A common method for measuring the friction durability of ATF is to use a SAE # 2 friction tester. This machine simulates high-speed engagement of the clutch by using the clutch as a brake, thereby absorbing a certain amount of energy. The energy of the system is selected to be equal to the energy absorbed by the clutch when completing one shift in an actual vehicle application. In that machine, a specific engagement speed, typically 3600 rpm, and a calculated inertia is used to provide a predetermined amount of energy to the test clutch and fluid. The clutch is lubricated by the fluid being evaluated and each deceleration (ie braking) of the system is referred to as one cycle. Many cycles are run continuously to assess frictional stability. With the increasing importance of friction stability by original equipment manufacturer (OEM), the total number of cycles required to demonstrate satisfactory friction durability has increased from a few hundred in the 1980s. The current standard has risen to over 10,000. See, for example, the service specification Ford MERCON® V automatic transmission fluid.

There are two ways to evaluate improved friction durability. The first method is one in which some friction properties are maintained over a longer period of time (ie, over a greater number of cycles). The second method makes it possible to reduce the change in each friction parameter over the same number of cycles. Both methods show that the shifting characteristics of the vehicle are consistent over longer miles.
Friction control in transmission fluids such as ATF, CVTF or DCTF is mainly due to the function of the friction modifier in the fluid. However, the thermal and oxidative stress with which such liquids are used in transmissions leads to additive degradation and thereby changes the liquid properties. Oxidative or thermal failure of friction modifiers is often first observed as increasing static friction in liquids. The increase in static friction causes a sudden shift that can be felt by a vehicle occupant as a jerk or lurch when the shift is complete. An increase in static friction is a common mode of transmission fluid failure. In some circumstances, however, oxidation of friction modifiers can make them more active species. In these situations, stiction can actually be reduced during service. Although not usually a problem for vehicle occupants, reducing static friction can reduce clutch capacity in the transmission. The reduction in capacity can cause the clutch to slip under high loads, such as towing or rapid acceleration, such that they overheat and eventually fail. Thus, the best transmission fluid has a highly stable static friction level that is well maintained even when used.

Conventionally, there are two methods for improving the friction stability of the transmission fluid. The first method is to increase the amount of friction modifier in the liquid. In this method, the effect of improving friction stability is desired by increasing the amount of friction modifier stored in the oil, but increasing the amount of friction modifier increases the coefficient of friction of the liquid to an undesirable level, particularly Produces an undesirable second effect of reducing to the coefficient of static friction. The second method improves the oxidation resistance of the liquid by the simultaneous use of an oxidation inhibitor additive, and in particular reduces the occurrence of polar products of oxidation that subsequently compete with the friction modifier on the friction surface. Is. Reducing liquid oxidation can therefore improve long-term control of friction.
US Pat. Nos. 5,750,476 and 5,840,662 report that a combination of antioxidants, oil-soluble phosphorus compounds and certain less effective friction modifiers can provide ATF with significant friction durability. There is. The fact that these less effective friction modifiers do not cause further reduction in the measured friction level once the concentration of the friction modifier reaches saturation in the liquid, even if the concentration is increased. Is characterized by The liquid can therefore be treated with a very high concentration of these ineffective friction modifiers to increase the storage of additives in the oil and still exhibit a satisfactory level of friction. Less effective friction modifier molecules are consumed by shearing or oxidation, but there is always enough concentration available to do them on the friction surface. Oil-soluble phosphorus-containing compounds must also be present to protect the system from wear.

However, such a solution essentially requires the use of large amounts of additives. What is needed is a more efficient and more cost effective solution to the use of chemical sources.
Similarly, additional requirements for oxidation inhibitors can lead to more complex formulations and higher development and use costs.

A class of friction modifiers, i.e. polyalkylene polyamine based friction modifiers, which are higher without loss of their friction control ability due to acylation of at least one secondary amino group present in the polyamine group. It has been found that thermal and oxidative stability can be obtained. When two or more secondary amino groups are present in the polyamine chain, particularly good stability is achieved by acylating several and preferably all of the secondary amino groups present in the friction modifier. Can do.
Such friction modifiers exhibit improved properties over conventional solutions and provide a more cost effective solution to the problem of friction durability in oils, particularly in transmission fluids. To do.

In a first aspect, the present invention provides a lubricating oil (and specifically, transmission fluid) composition comprising an oil-soluble phosphorus-containing compound and a polyalkylene polyamine-based friction modifier comprising at least one hydrocarbyl substituent. Wherein the hydrocarbyl substituent contains 6 to 30 carbon atoms and at least one secondary amino group in the polyamine chain of the friction modifier is acylated to the corresponding amide group.
More specifically, the present invention provides:
(A) a large amount of lubricating oil; and (b) a lubricating oil (and specifically comprising: an additive combination in an amount effective to improve friction stability, including (i) and (ii) below: Regarding transmission composition):
(I) one or more compounds selected from the group of compounds represented by the following structures (I), (II) and (III) and an acylating agent R ₃ COX wherein R ₃ is a hydrocarbyl group and Friction modifier containing reaction product of X is a leaving group:

（式中、ＲはＣ_6-30アルキル又はアルケニル基であり；Ｒ₁は以下の構造（ＩＶ）により表されるポリアルキレンポリアミン基である：

Wherein R is a C _6-30 alkyl or alkenyl group; R ₁ is a polyalkylene polyamine group represented by the following structure (IV):

（式中、ｎ及びｍは、各々独立して、１〜６の整数であり；及びＲ₂は、アルキル又はアリール基又はそれらのヘテロ原子含有誘導体であり又は以下の構造（Ｖ）、（ＶＩ）及び（ＶＩＩ）：

Wherein n and m are each independently an integer from 1 to 6; and R ₂ is an alkyl or aryl group or a heteroatom-containing derivative thereof, or the following structures (V), (VI ) And (VII):

より選択される））；及び
（ｉｉ）油溶性リン含有化合物。

And (ii) an oil-soluble phosphorus-containing compound.

  In a subsequent embodiment, at least one and preferably each secondary nitrogen in structure (IV) of structures (I), (II) and (III) is reacted with an acylating agent respectively. Have been converted to the amide by giving the corresponding structures (VIII), (IX) and (X).

（式中、Ｒ、Ｒ₁、Ｒ₂、Ｒ₃及びｎは、先に定義したものであり及びｐ＋ｑ＝ｍ（ここで、ｍは、先に定義したものである）であり、但し、ｐ≧１である。）
しかしながら、最も好ましくは、ｑ＝０及びｐ＝ｍである。

Wherein R, R ₁ , R ₂ , R ₃ and n are as defined above and p + q = m, where m is as defined above, where p ≧ 1.)
Most preferably, however, q = 0 and p = m.

In all of the above structures, R ₃ is preferably a C _1-20 hydrocarbyl substituent, more preferably an alkyl or aryl group or one of their heteroatom-containing analogs. Even more preferably, R ₃ is a C _1-10 alkyl or aryl group and most preferably R ₃ is a C _1-6 alkyl or aryl group, especially methyl, ethyl, propyl or butyl.
Other aspects of the present invention include: a polyalkylene polyamine-based friction modifier (b) (i) itself as defined above; in combination with an oil-soluble phosphorus-containing compound as defined above. An additive composition comprising a friction modifier; a method of imparting friction stability to a lubricating oil, wherein an effective amount of an additive combination as defined above is used to improve friction stability. And in lubricating oils, the additive compositions defined above are used in an amount effective to improve their frictional stability.
Further aspects and embodiments of the present invention will become apparent from the following detailed description.

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for improving the friction stability of a lubricating oil without adversely reducing the coefficient of friction. It involves the combined use in lubricants of friction modifiers derived from oil-soluble sources of phosphorus and defined polyalkylene polyamines. This additive combination imparts significant frictional stability to the lubricating oil, particularly the transmission fluid.
The advantages of the present invention are intended to be applicable to a wide variety of lubricating oils (eg, crankcase engine oils, etc.) in which friction modifiers are effectively used, but particularly preferred compositions include transmission fluids. In particular, automatic transmission fluid (“ATF”), continuously variable transmission fluid (“CVTF”) and double clutch transmission fluid (“DCTF”). Other less preferred types of transmission fluids that fall within the scope of the present invention are gear oils, hydraulic fluids, tractor fluids and universal tractor fluids. These transmission fluids can be blended in various base oils and additives that impart various additional performances.

Polyalkylene polyamine based friction modifiers of the present invention Preferred friction modifiers of the present invention are succinimides comprising at least one hydrocarbyl substituent, wherein the hydrocarbyl substituent comprises 6 to 30 carbon atoms and preferably Is an alkenyl group or a fully saturated alkyl analog); or one or more structures formed by reaction of the corresponding alkenyl or alkyl carboxylic acid and a polyalkylene polyamine, and 6 to Either prepared from carboxylic acid amides having at least one alkenyl or alkyl chain containing 30 carbon atoms.
The most preferred type of friction modifier is first an alkyl or alkenyl succinic anhydride (wherein the alkyl or alkenyl substituent is an isomerized chain), one or more polyalkylene polyamines, preferably one or more polyethylenes. It is produced by reacting with a polyamine. In such preferred materials, the isomerized chain is attached to the alpha carbon atom of the succinimide ring and through a tertiary carbon atom, as illustrated in the following structure for an alkenyl substituted structure reacted with a polyethylene polyamine. A bifurcated substituent attached to the ring alpha carbon atom results:

（式中、ｘ及びｙは、独立した整数であり、それらの合計は、１〜２５であり及びｚは、１〜１０の整数である）。

(Wherein x and y are independent integers, their sum is 1 to 25 and z is an integer of 1 to 10).

The preparation of isomerized alkenyl succinic anhydrides is well known and described, for example, in US Pat. No. 3,382,172. Usually, these materials are produced by heating the α-olefin using an acidic catalyst to transfer the double bond to the internal position. This olefin (2-ene, 3-ene, etc.) mixture is then thermally reacted with maleic anhydride. Typically, C ₆ (1-hexene) to C ₃₀ (1-triacontene) olefins are used. Suitable isomerized alkenyl succinic anhydrides of structure (I) include isodecyl succinic anhydride (x + y = 5 in the above formula), isododecyl succinic anhydride (x + y = 7), isotetradecyl succinic anhydride (x + y = 9). ), Isohexadecyl succinic anhydride (x + y = 11), isooctadecyl succinic anhydride (x + y = 13) and isoeicosyl succinic anhydride (x + y = 15). Preferred materials are isohexadecyl succinic anhydride and isooctadecyl succinic anhydride, which give particularly good performance.
The material produced by this method contains one double bond (alkenyl group) in the alkyl chain. Alkenyl substituted succinic anhydrides can be readily converted to their saturated alkyl analogs by hydrogenation.
The isomerized alkenyl or alkyl-substituted succinic anhydride can then be reacted with a suitable amine to produce a friction modifier of the type shown in structure (I) from which the friction modifier (b ) (I) is then formed by acylation with R ₃ COX.

Instead of an isomerized alkenyl or alkyl succinic anhydride, a carboxylic acid containing at least one alkenyl or alkyl chain containing 6 to 30 carbon atoms is reacted with a suitable amine to give structures (II) and (III) A friction modifier of the type shown in can be produced. Such acids are preferably alkyl or alkenyl acids containing from 12 to 22 carbon atoms and in particular from 16 to 20 carbon atoms. The friction modifiers of the present invention are then formed by acylation with R ₃ COX.
Suitable amines useful for preparing friction modifiers of structure (I), (II) and (III) are represented by the following structure (XI):

（式中、ｎ及びｍは、各々独立して、１〜６の整数であり及びＲ₂は、先に定義したものである）。

(Wherein n and m are each independently an integer from 1 to 6 and R ₂ is as defined above).

  The amine of structure (XI) can be prepared by reaction of a primary polyamine. A particularly useful class of such amines are the polyalkylene polyamines of the general formula (XII):

（式中、ａは、１〜５、好ましくは、２〜４の整数であり；及び各々のｎは、独立して、１〜６、好ましくは、１〜４の整数である）。

(Wherein a is an integer of 1-5, preferably 2-4; and each n is independently an integer of 1-6, preferably 1-4).

Non-limiting examples of suitable polyamine compounds include diethylenetriamine, triethylenetetramine, tetraethylenepentamine and pentaethylenehexamine. Low cost mixtures of polyamines having 5 to 7 nitrogen atoms per molecule are available as Polyamine H, Polyamine 400 and Polyamine E-300 from Dow Chemical Company.
Such polyamines can be reacted with the succinic anhydride substituted with alkenyl groups or their fully saturated alkyl analogs to form structure (I); or the alkenyl or alkyl carboxylic acid Can be reacted to form structure (II) or (III).
Preferred friction modifiers of the present invention are usually produced by heating the isomerized alkenyl succinic anhydride (or its saturated alkyl analog) with the polyamine and removing the water formed. . However, other manufacturing methods are known and can be used. The ratio of primary amine groups to succinic anhydride groups is usually 1: 1. In the case of a diamine or polyamine (the molecule is terminated at both ends with a primary amine), both terminal amine groups of the molecule are reacted with a substituted succinic anhydride to yield the following structure (XIII It is desirable to produce a material:

（式中、Ｒ、ａ及びｎは、先に定義したものである）。

(Wherein R, a and n are as defined above).

The acylating agent of the present invention is a material capable of converting a secondary amine to an amide. Such materials have the formula R ₃ COX, where R ₃ is a hydrocarbyl group and X is a leaving group, which leaving group is also acylated so as to form a ring structure. It may be bonded to the R ₃ group of the agent.
R ₃ is preferably a C _1-20 hydrocarbyl substituent, preferably an alkyl or aryl group or one of their heteroatom-containing analogs. More preferably, R ₃ is a C _1-10 alkyl or aryl group and most preferably R ₃ is a C _1-6 alkyl or aryl group. Most preferably R ₃ is alkyl, such as methyl, ethyl, propyl or butyl.
Preferred acylating agents for use are in particular acetic anhydride, propionic anhydride, butyric anhydride, trifluoroacetic anhydride, acetyl chloride, propionic chloride, butyric acid bromide, butyrolactone, caprolactone, methyl acetate, ethyl acetate, Butyl acetate, butyl propionate and butyl butyrate. Acetic anhydride is most preferred.
Preferred friction reducing agents of the present invention are those prepared by first reacting alkenyl succinic anhydride with polyamine (XI) and then with acetic anhydride. The most preferred products of the present invention are those prepared by reacting isomerized alkenyl succinic anhydride with polyamine (XII), which is then reacted with acetic anhydride.

  The most preferred friction modifier (b) (i) of the present invention has the following structure, which is suitably formed by acylating the reaction product of diethylenetriamine and the required isomerized octadecenyl succinic anhydride. can do:

It has been found that this material provides particularly good performance in the present invention. Both the friction modifier additive comprising this compound and the compound itself represent a further aspect of the present invention.
Although effective amounts of friction modifiers can be used in various embodiments of the present invention, the treat rate of the friction modifier is usually from about 0.1 to about 10 weight percent, preferably in the lubricating composition, 0.5-7 mass% and most preferably 1.0-5.0 mass%.
An example of the production of a typical friction modifier material of the present invention is described below. These examples are for illustrative purposes and the invention is not limited to the specific details set forth in the examples.

Production example
Example A (Production of isomerized succinimide)
A 1 liter round bottom flask equipped with a mechanical stirrer, nitrogen sweep, Dean Stark trap and condenser was charged with 352 grams (1.00 mole) of isooctadecenyl succinic anhydride (Dixie Chemical). ODSA). A slow nitrogen sweep was started, stirring was started and the material was heated to 130 ° C. Immediately thereafter, 95 grams (0.50 mole) of commercially available tetraethylenepentamine was slowly added to hot stirred isooctadecenyl succinic anhydride via an additional funnel. The temperature of the mixture was raised to 150 ° C. and maintained for 2 hours. During this heating time, 10 ml (~ 50% of theoretical yield) of water was collected in the Dean Stark trap. The flask was cooled to give the product. Yield: 435 grams. Percent nitrogen: 8.1.

Example B (Production of isomerized succinimide)
The procedure was as in Example A except that 700 grams (2.0 moles) of isooctadecenyl succinic anhydride and 103 grams (1.0 moles) of diethylenetriamine were used. The recovered water was 32 ml. Yield: 765 grams. Percent nitrogen: 5.5.

Example C (Preparation of the acylated isomerized succinimide of the present invention)
Into a 1 liter round bottom flask equipped with a mechanical stirrer, nitrogen sweep, Dean-Stark trap and condenser was placed 765 grams (1.0 mole) of the product of Example B. A slow nitrogen sweep was started, stirring was started and the material was heated to 90 ° C. 102 grams (1.0 mole) of acetic anhydride was added dropwise via an additional funnel. When the addition was complete, the temperature was raised to 140 ° C. and maintained for 3 hours. Residual acetic acid was removed by distillation at 150 ° C. and 50 mm Hg. Yield: 805 grams. Percent nitrogen: 5.2.

Example D (Preparation of the acylated isomerized succinimide of the present invention)
The procedure was as in Example C except that 765 grams (1.0 mole) of the product of Example B and 131 grams (1.15 mole) of caprolactone were used. The mixture was heated at 170 ° C. for 6 hours and then 2 milliliters of stannous octoate was added. After the addition of octanoate, the temperature rose to 180 ° C. and was maintained for an additional 4 hours. Yield: 895 grams. Percent nitrogen: 4.7.

Example E (Preparation of the acylated isomerized succinimide of the present invention)
Into a 1 liter round bottom flask equipped with a mechanical stirrer, nitrogen sweep, Dean Stark trap and condenser was placed 429 grams (0.50 mole) of the product of Example A. A slow nitrogen sweep was started, stirring was started and the material was heated to 90 ° C. 61 grams (0.5 mole) of acetic anhydride was added dropwise via an additional funnel. When the addition was complete, the temperature was raised to 140 ° C. and maintained for 3 hours. Residual acetic acid was removed by distillation at 150 ° C. and 50 mm Hg. Yield: 485 grams. Percent nitrogen: 7.1.

Example F (Preparation of acylated product of isostearic acid-TEPA)
A 1 liter round bottom flask equipped with a mechanical stirrer, nitrogen sweep, Dean Stark trap and condenser was charged with 402 grams (1.37 moles) of isostearic acid. A slow nitrogen sweep was started, stirring was started and the material was heated to 100 ° C. 130 grams (0.69 mol) of tetraethylenepentamine (TEPA) was added dropwise via a dropping funnel over 1 hour. When the addition was complete, the mixture was heated to 160 ° C. and maintained for 6 hours, during which time 24 grams of water was recovered (98% of theory). The material was cooled to 100 ° C. and 71 grams (0.69 mol) of acetic anhydride was added dropwise via a dropping funnel. When the addition was complete, the temperature was raised to 140 ° C. and maintained for 3 hours. Residual acetic acid was removed at 130 ° C. and 50 mm Hg. Yield: 560 grams. Percent nitrogen: 8.8%.

Oil-soluble phosphorus-containing compounds In its broadest aspect, the oil-soluble phosphorus-containing compounds useful in the present invention may vary widely and are not limited by chemical type. The only limitation is that the material is oil soluble so that the phosphorus containing compound can be dispersed and transported to its site of action within the lubricating oil system. Examples of suitable phosphorus compounds are: phosphites and thiophosphites (monoalkyl, dialkyl, trialkyl and their partially hydrogenated analogs); phosphates and thiophosphates; inorganic phosphorus such as , Amines treated with phosphorous acid, phosphoric acid or their thio analogs; zinc dithiodiphosphate; amine phosphate. Examples of particularly suitable phosphorus compounds include: mono-n-butyl-hydrogen-acid-phosphite; di-n-butyl-hydrogen phosphite; triphenyl phosphite; triphenylthiophosphite Tri-n-butyl phosphate; dimethyl octadecenyl phosphonate, 900 MW polyisobutenyl succinic anhydride (PIBSA) polyamine dispersant (after treated with H ₃ PO ₃ and H ₃ BO ₃ (eg, US Pat. No. 4,857,214); No.))); zinc (di-2-ethylhexyl dithiophosphate).
Preferred oil-soluble phosphorus compounds are esters of phosphoric acid and phosphorous acid. These materials include dialkyl, trialkyl and triaryl phosphites and phosphates. Preferred oil-soluble phosphorus compounds are mixed thioalkyl phosphite esters, such as those prepared in US Pat. No. 5,314,633 (which is incorporated herein by reference). The most preferred phosphorus compound is, for example, a thioalkyl phosphite as described in Example G below.
The phosphorus compounds of the present invention can be used in oil in any effective amount. However, typical effective concentrations of such compounds are those capable of delivering about 5 to about 5000 ppm phosphorus to the oil. A preferred concentration range is about 10 to about 1000 ppm phosphorus in the finished oil and the most preferred concentration range is about 50 to about 500 ppm.

Example <br/> Example G
The alkyl phosphite mixture was made by placing 194 grams (1.0 mole) of dibutyl hydrogen phosphite in a round bottom four neck flask equipped with a reflux condenser, stirrer and nitrogen bubble generator. The flask was flushed with nitrogen, sealed and agitation started. Dibutyl hydrogen phosphite was heated to 150 ° C. under vacuum (−90 kPa) and 190 grams (1 mole) of hydroxylethyl-n-octyl sulfide was added via an addition funnel over about 1 hour. During the addition, about 35 ml of butanol was collected in the cold trap. Heating was continued for about 1 hour after the addition of hydroxylethyl-n-octyl sulfide, but no further butanol was generated. The reaction mixture was cooled and analyzed for phosphorus and sulfur. In the final product, the TAN was 115, the phosphorus content was 8.4% and the sulfur content was 9.1%.
Other additives known in the art may be added to the lubricating oil of the present invention or included in the additive composition of the present invention. These additives include dispersants, antiwear agents, corrosion inhibitors, detergents and extreme pressure additives. They are typically disclosed, for example, in “Lubricant Additives” by CV Smallheer and R. Kennedy Smith, 1967, pp. 1-11 and US Pat. No. 4,105,571.

Typical amounts of these additives in ATF are outlined below.

Suitable dispersants include: long chain (ie higher than 40 carbon atoms) substituted hydrocarbyl succinimide and hydrocarbyl succinamide, long chain (ie higher than 40 carbon atoms) hydrocarbyl substituted succinate. Mixed esters / amides of acids, hydroxy esters of such hydrocarbyl-substituted succinic acids, and Mannich condensation products of long-chain (ie, higher than 40 carbon) hydrocarbyl-substituted phenols, formaldehyde and polyamines. Mixtures of such dispersants can also be used.
A preferred dispersant is a long chain alkenyl succinimide. These include, for example, acyclic hydrocarbyl substituted succinimides formed with various amines or amine derivatives that are widely disclosed in the patent literature. The use of alkenyl succinimides treated with inorganic phosphoric acid (or their anhydrides) and boronating agents is also suitable for use in the compositions of the present invention because they are fluoroelastomers and silicon-containing elastomers. This is because the compatibility with elastomer seals made from such materials is very high. A polyisobutenyl succinimide formed from polyisobutenyl succinic anhydride and an alkylene polyamine such as triethylenetetramine or tetraethylenepentamine (wherein the polyisobutenyl substituent has a number average molecular weight of 500 to 5000 (preferably 800 to 2500). Is particularly suitable) derived from polyisobutene). The dispersant may be post-treated with a number of reagents known to those skilled in the art (see, for example, US Pat. Nos. 3,254,025, 3,502,677 and 4,857,214).

The additive combination of the present invention can be combined with other desired lubricating oil additives to form a concentrate. Typically, the active ingredient (ai) level range of the concentrate is 20-90%, preferably 25-80%, most preferably 35-75% by weight of the concentrate. . The balance of the concentrate is typically a diluent consisting of a lubricating oil or solvent.
The lubricating oils useful in the present invention are derived from natural lubricating oils, synthetic lubricating oils and mixtures thereof. In general, both natural and synthetic lubricating oils each have a kinematic viscosity of from about 1 to about 100 mm ² / s (cSt) at 100 ° C., but for main applications, the viscosity of each oil is about 2 to about 100 ° C. It needs to be about 8 mm ² / s (cSt).
Natural lubricating oils include animal oils, vegetable oils (eg, castor oil and lard oil), petroleum oils, mineral oils, and oils derived from coal or shale. A preferred natural lubricating oil is mineral oil.
Suitable mineral oils include all common mineral oil base stocks. An example of this is an oil whose chemical structure is naphthenic or paraffinic. Oils are purified by conventional methodologies using acids, alkalis and clays or other agents, such as aluminum chloride, or they are, for example, solvents such as phenol, sulfur dioxide, furfural and dichlorodiethyl ether. ) Etc. may be extracted oil produced by solvent extraction. They may be hydrotreated or hydrofine, dewaxed by cooling or catalytic dewaxing methods, or hydrocracked. Mineral oils can be made from natural crude sources or can consist of isomerized wax material or residue (by other refining methods).

Typically, mineral oils, kinematic viscosity is at 100 ° C., will 2.0~8.0mm ² / s (cSt). Preferred mineral oils have a kinematic viscosity of 2-6 mm ² / s (cSt) at 100 ° C. and most preferred mineral oils have a kinematic viscosity of 3-5 mm ² / s (cSt) at 100 ° C. .
Synthetic lubricating oils include the following: hydrocarbon oils and halogen-substituted hydrocarbon oils, such as oligomerized, polymerized and interpolymerized olefins [eg, polybutylene, polypropylene, propylene, isobutylene. Copolymers, chlorinated polyactenes, poly (1-hexene), poly (1-octene), poly (1-decene) and mixtures thereof]; alkylbenzenes [eg dodecylbenzene, tetradecylbenzene, dinonylbenzene and di ( 2-ethylhexyl) benzene etc.]; polyphenyl [eg biphenyl, terphenyl and alkylated polyphenyl etc.]; and alkylated diphenyl ether, alkylated diphenyl sulfide, and derivatives, analogs and homologues thereof. Preferred oils of this class of synthetic oils are α-olefin oligomers, especially 1-decene oligomers.
Synthetic lubricating oils also include alkylene oxide polymers, interpolymers, copolymers, and derivatives thereof, where the terminal hydroxyl groups have been modified by esterification, etherification, and the like. Examples of this class of synthetic oils include: polyoxyalkylene polymers produced by polymerization of ethylene oxide or propylene oxide; alkyl and aryl ethers of these polyoxyalkylene polymers (eg, having an average molecular weight of 1000-methyl-polyisopropylene glycol ether and polypropylene glycol diphenyl ether having a molecular weight of 1000-1500; and their mono- and polycarboxylic esters (eg acetates, mixed C _3-8 fatty acid esters, and tetra C ₁₂ oxo acid diester of ethylene glycol).

Other suitable classes of synthetic lubricating oils include dicarboxylic acids (eg, phthalic acid, succinic acid, alkyl succinic acid and alkenyl succinic acid, maleic acid, azelaic acid, suberic acid, sebasic acid, fumaric acid, adipine Acid, linoleic acid dimer, malonic acid, alkylmalonic acid and alkenylmalonic acid) and various alcohols (eg, butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether and propylene glycol) Etc.). Specific examples of these esters include: dibutyl adipate, di (2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl By reacting phthalate, didecyl phthalate, dieicosyl sebacate, 2-ethylhexyl diester of linoleic acid dimer, and 1 mol of sebacic acid with 2 mol of tetraethylene glycol and 2 mol of 2-ethylhexanoic acid Complex esters formed. A preferred type of oil of this class is C _4-12 alcohol adipate.
Esters useful as synthetic lubricating oils also include those prepared from _C5-12 monocarboxylic acids and polyols and polyol ethers such as neopentyl glycol, trimethylolpropane pentaerythritol, dipentaerythritol and tripentaerythritol. Is mentioned.

Silicon-based oils (eg, polyalkyl, polyaryl, polyalkoxy or polyaryloxysiloxane oils and silicate oils) constitute another useful class of synthetic lubricating oils. These oils include tetraethyl silicate, tetraisopropyl silicate, tetra (2-ethylhexyl) silicate, tetra (4-methyl-2-ethylhexyl) silicate, tetra (p-tert-butylphenyl) silicate, hexa (4-methyl- 2-pentoxy) disiloxane, poly (methyl) siloxane, poly (methylphenyl) siloxane and the like. Other synthetic lubricating oils include liquid esters of phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl phosphate and diethyl ester of decylphosphonic acid), polymeric tetrahydrofurans and polyalphaolefins.
The lubricating oil can be derived from refined, re-refined oils or mixtures thereof. Unrefined oil is obtained directly from natural or synthetic sources (eg coal, shale or tar sand bitumen) without further purification or treatment. Examples of unrefined oils include shale oil obtained directly by retorting operations, petroleum oil obtained directly by distillation or ester oil obtained directly by an esterification process, each of which is then Used without further processing. Refined oils are similar to unrefined oils, except that refined oils have been treated in one or more purification steps to improve one or more properties. Suitable purification techniques include distillation, hydrotreating, dewaxing, solvent extraction, acid or base extraction, filtration and percolation, all of which are known to those skilled in the art. Rerefined oil is obtained by treating spent oil in a manner similar to that used to obtain refined oil. These rerefined oils are also known as reclaimed or reprocessed oils and are often additionally processed by techniques for removal of spent additives and oil breakdown products.

Another class of suitable lubricating oils are base stocks produced by oligomerization of natural gas feedstocks or wax isomerization. Although these base stocks can be referred to by many names, they are usually known as gas liquefaction (GTL) or Fischer-Tropsch base stocks.
Where the lubricating oil is a mixture of natural and synthetic lubricating oils (ie, partially synthetic), the choice of partially synthetic oil components can vary widely, but a particularly useful combination is mineral oil and polyalphaolefin (PAO). ), In particular, an oligomer of 1-decene.
The following examples are set forth in order to specifically illustrate the invention described in the claims. However, it should be understood that the invention is not limited to the specific details set forth in the examples. All parts and ratios are by weight unless otherwise specified.

Example
The Ford MERCON® friction test (MERCON® automatic transmission fluid specification for service, dated September 1, 1992, section 3.8) was modified to Proof of friction durability. The Ford test focuses on friction durability by using high test energy and a small amount of liquid per cycle. This high energy repetitive dissipation into this small amount of test liquid at 10,000 cycles evaluates the ability of the liquid to maintain constant frictional properties with great effort. The Ford test method was modified as shown below.
Tests conducted:
Friction material: Borg Warner 6100 (no groove)
Test temperature: 115 ° C
Full test cycle: 10,000
Cycles per minute: 3
Total energy per cycle: 20,400J
Piston pressurization: 275 kPa
Static friction measurement:
Speed: 4.37rpm
Pressurization: 275 kPa
Static friction: measured 2 seconds after rotation

Since the principle role of the friction modifier of the present invention is to reduce the static friction and maintain its level over the life of the liquid, the product of the present invention can be treated with a coefficient of static friction (Mu-s or μ _s ). In the SAE # 2 friction test, which compares the stability of the non-acylated version.
The blend of the three test liquids was carried out using exactly the same base lubricating oil, dispersant, antioxidant and viscosity modifier. The test blend was prepared as described in US Pat. No. 5,314,633 and contained the most preferred oil soluble phosphorus source (Example G above). To each liquid, 3.0 wt% friction modifier was added as follows:
Liquid A contains the product of Example B,
Liquid B contains the product of Example C,
Liquid C contained the product of Example D.
The composition of the test liquid and a summary of the test results are listed in Table 1 below.
As can be seen from Table 1, the normal friction modifier of Example B (Liquid A) reduced the static friction by 0.013 over a period of 500 to 10,000 cycles. For liquids containing the product of the invention, the products of Examples C and D, the change in static friction was small: Liquid B had a reduction of 0.002 and Liquid C had a reduction of 0.003.
Thus, it is clear that acylation of alkylene amine based friction modifiers improved friction stability during testing.

  The principles, preferred embodiments and examples of the present invention have been described above. However, the inventions intended to be protected herein should not be construed as limited to the particular types disclosed, because these are illustrative rather than limiting Because it should be regarded as. Changes and modifications can be made by those skilled in the art without departing from the spirit of the invention.

Claims (4)

A composition comprising an additive combination in an amount effective to improve friction stability, comprising: (a) a large amount of a lubricating base oil; and (b) the following (i) and (ii):
(I) at least one reaction product comprising a reaction product of a compound represented by structure (XIII ) below and an acylating agent R ₃ COX wherein R ₃ is a hydrocarbyl group and X is a leaving group Friction modifier:

(Wherein R is a C _6-30 alkyl or alkenyl group; a is an integer from 1 to 5; n is an integer from 1 to 6); and (ii) at least one oil-soluble thioalkyl phosphine. Fit compound.   The composition according to claim 1, which is a transmission liquid. A friction modifier comprising a reaction product of a compound represented by the following structure (XIII) and an acylating agent R ₃ COX (wherein R ₃ is a hydrocarbyl group and X is a leaving group) An additive composition comprising a thioalkyl phosphite compound in combination.

Wherein R is a C _6-30 alkyl or alkenyl group; a is an integer from 1 to 5; n is an integer from 1 to 6. A method for imparting friction stability to a lubricating oil, comprising a compound represented by the following structure (XIII) and an acylating agent R ₃ COX (wherein R ₃ is a hydrocarbyl group and X is a leaving group) including methods that friction modifiers, are added to the lubricating oil in combination with oil-soluble thioalkyl phosphite compound comprising the reaction product of).

Wherein R is a C _6-30 alkyl or alkenyl group; a is an integer from 1 to 5; n is an integer from 1 to 6.