KR100780580B1 - Power transmission fluids with enhanced lifetime characteristics - Google Patents

Abstract

A power transmission fluid with improved features, a method of lubricating a transmission and a vehicle comprising the transmission fluid are disclosed. Transmission fluids include silicon-containing antifoaming agents having a kinematic viscosity at 25 ° C. of greater than about 20,000 centistokes in an amount effective to provide gear shift times of less than about 0.75 seconds throughout the useful life of the transmission fluid.

Description

POWER TRANSMISSION FLUIDS WITH ENHANCED LIFETIME CHARACTERISTICS}

Additional features and advantages of the exemplary embodiments disclosed herein may be apparent from the detailed description of the invention contemplated in conjunction with the following drawings, which are not to scale, and wherein throughout the drawings reference numerals refer to like members. Indicates:

1 is a curve of 1-2 variation on fluid surface tension;

2 is a delta for the GMCT cycle. TAN curve.

Field of technology

The present disclosure relates in particular to power transmission fluids with improved characteristics for aged fluids. The power transmission fluids disclosed herein include fluids suitable for use with automatic transmissions (ATFs) and / or manual transmissions. "Automatic transmission" herein means both a continuously variable transmission and a conventional automatic transmission known as CVT.

Background and overview

III-G 사양으로 공지되어 있다. 그러나, 신규한 사양이 2003 년 6 월에 공표되었다. 상기 신규한 사양은 상표명 DEXRON

III-H 하에 공지되어 있으며, DEXRON

III-G 사양으로부터의 업그레이드이다. III-G 는 III-H 와 2 가지 현저한 차이점이 있다: 1) GM 산화 시험 (GMOT) 길이가 300 시간에서 450 시간으로 증가되었고, 2) GM 순환 시험 (GMCT) 의 기간이 20,000 순환에서 32,000 순환으로 증가되었다. 두 경우 모두, 시험 길이가 증가하면서 시험 조건 및 성능 요구사항이 일정하게 유지되었다. 예를 들어, 오일의 총 산가 (TAN) 는 GMOT 동안에는 3.25 (델타 TAN) 을 초과하여 증가해서는 안된다. GMCT 에 대해, 델타 TAN 는 2.0 를 초과하여 증가해서는 안되며, 제 1 및 제 2 기어 사이의 변동에 대한 접촉유지 시간 (engagement time) (1 - 2 변동 시간) 이 GMCT 를 통틀어 0.30 내지 0.75 초 이내로 제어되어야만 한다. 전반적인 필요 성능 변화는 자동 변속기 유체 (ATF) 제형자 (formulator) 에게 어려운 도전 과제를 제공한다. GMCT 에 대한 델타 TAN 이 GMOT 에 대한 것보다 더 낮으므로, GMCT 기준을 통과할 수 있는 유체는 또한 GMOT 기준에 부합할 수 있다. Automatic Transmission Fluid (ATF) is designed to meet certain industry standards. The current standard for ATF is DEXRON

Known as III-G specification. However, new specifications were published in June 2003. The new specifications are brand name DEXRON

Known under III-H, DEXRON

This is an upgrade from the III-G specification. III-G differs from III-H in two significant ways: 1) the length of the GM oxidation test (GMOT) has been increased from 300 hours to 450 hours, and 2) the duration of the GM circulation test (GMCT) has been increased from 20,000 cycles to 32,000 cycles. Increased to. In both cases, test conditions and performance requirements remained constant as test lengths increased. For example, the total acid value (TAN) of oil should not increase above 3.25 (delta TAN) during GMOT. For GMCT, the delta TAN should not increase above 2.0, and the engagement time (1-2 change time) for changes between the first and second gears is controlled within 0.30 to 0.75 seconds throughout GMCT. Should be. The overall required performance change presents a challenging challenge for automatic transmission fluid (ATF) formulators. Since the delta TAN for GMCT is lower than for GMOT, fluids that can pass GMCT criteria may also meet GMOT criteria.

In order for the automatic transmission to operate properly, the automatic transmission fluid must be able to effectively control the contact hold time during the change from one gear to the next. However, as the fluid ages, the variation time tends to increase. There are two failure modes that can be responsible for increasing GMCT 1-2 variation time. One is the increase in air dispersed in the oil as they age, and the other is pyrolysis of the band friction material.

One factor that may contribute to the increase of air dispersed in the oil as it ages may be a decrease in surface tension in the oil. The reduction in surface tension is mostly caused by oil oxidation, which provides soluble and insoluble hydrophilic compounds, since the oxidized product is known to reduce surface tension. The decrease in surface tension also increases the amount of foaming of the oil. As the foaming increases, the amount of air bubbles present in the oil increases, increasing the pressureability of the oil. When pressure is applied to the bands and drums to activate 1-2 fluctuations, the fluid compression rate is greater due to the presence of air bubbles or foams, requiring longer fluctuation times. Thus, there is a continuing need for improved power transmission fluids, which are less susceptible to foam formation as the oil ages during use.

In this regard, in one exemplary embodiment a silicon-containing antifoaming agent having a kinematic viscosity at 25 ° C. of greater than about 20,000 centistokes is effective to provide a gear shift time of less than about 0.75 seconds throughout the useful life of the transmission fluid. A power transmission fluid containing is provided.

In another exemplary embodiment, there is provided an automatic transmission fluid containing: a) an oil having a lubricating viscosity that has a kinematic viscosity at 100 ° C. of 2 to 10 centistokes; b) a weight percent of 2,5-dimercapto-1,3,4-thiadiazole (DMTD) and / or a derivative or precursor thereof sufficient to provide a fluid having antiwear characteristics; c) a silicon-containing antifoaming agent having a kinematic viscosity at 25 ° C. of greater than about 20,000 centistokes; And d) acrylates, methacrylates, polyacrylates, polymethacrylates or copolymers or terpolymers thereof.

In another exemplary embodiment, a method of reducing gear shift time in an automatic transmission including an aged transmission fluid is provided. The method includes lubricating a transmission with a fluid containing oil having a kinematic viscosity at 100 ° C. of 2 to 10 centistokes and an effective amount of a silicon-containing antifoaming agent having a kinematic viscosity at 25 ° C. above about 20,000 centistokes, wherein aging The gear shift time for the prepared fluid is reduced compared to the gear shift time for the aged fluid in the transmission containing an antifoaming agent having a kinematic viscosity at 25 ° C. of less than about 20,000 centistokes.

Typically, antifoams are used to reduce the tendency of the fluid to decrease by the surface tension of the fluid from which air is released. The addition of more conventional antifoams can increase the ability of the fluid to release air therefrom. However, as the fluid ages, as in the GMCT described above, the effectiveness of conventional antifoaming agents decreases. As the effectiveness decreases, the 1-2 variation time decreases.

An advantage of embodiments of the present disclosure is that certain high viscosity silicon-containing antifoams can be used in power transmission fluid applications to maintain a lower increase in 1-2 change times in GMCT for aged fluids. Without being bound by theory, it is believed that higher viscosity silicon-containing defoamers can increase the surface tension of the fluid and maintain the increased surface tension even as the fluid ages. Thus, high viscosity silicon-containing defoamers can initially reduce foaming by preventing air from dissolving or dispersing in the fluid, even if the fluid ages.

In addition to the high viscosity defoamers, the compositions described herein may also include boron provided by borated dispersants or other borated materials, such as borated epoxides or mixtures thereof. The composition may further comprise phosphorus, which may be provided by phosphate esters such as dibutyl hydrogen phosphite, dihydrogen phosphite diphenyl, triphenyl phosphite and / or triphenyl thiosulfate.

Another feature of the disclosed embodiments includes directly injecting into the automatic transmission a composition containing at least one silicon-containing antifoaming agent having a kinematic viscosity at 25 ° C. of greater than about 20,000 centistokes in the presence or absence of carrier oil. It is to provide a treatment method.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further description of the disclosed embodiments as claimed.

example Implementation  details

The disclosed embodiments utilize antifoams with exceptionally high kinematic viscosity for ATF applications. The antifoam can be used for fully formulated ATF or can be injected directly as a top treat to the ATF in the transmission to reduce the clutch connection time (clutch contact time). In an exemplary embodiment, the ATF also contains an optional air release agent. The disclosed embodiments also include an additive system comprising the above mentioned exceptionally high viscosity defoamers, which can be mixed with other compositions by ATF formulators for providing ATF.

Antifoam

Suitable silicon-containing defoamers according to the present disclosure include, but are not limited to, fluorosilicone, polydimethylsiloxane, phenyl-methyl polysiloxane, linear siloxane, cyclic siloxane, branched siloxane, silicone polymers and copolymers, organosilicon copolymers and these Mixtures thereof. The antifoaming agent has a kinematic viscosity at 25 ° C. of greater than about 20,000 centistokes, generally from about 40,000 to about 80,000 centistokes at 25 ° C., referred to herein as a “high viscosity antifoaming agent”. The high viscosity defoamers are available from Dow Corning, Midland, Michigan under the trade name DOW CORNING 200 (R).

High viscosity defoamers may be formulated with conventional ATF, or may be injected directly (eg, via a syringe), or otherwise added to an automatic transmission. Due to the high shear rate of many automatic transmission pumps (especially CVT pumps), the antifoam can be mixed quickly and effectively with ATF.

The treatment rate of the high viscosity defoamer (ie the amount of high viscosity defoamer required to effectively reduce gear fluctuation time) is from about 1 to about 100 ppm of silicon, more preferably from 10 to about 80, relative to the finished lubricated transmission oil / ATF. It is essential to deliver ppm, with the exception that the defoamer is substantially homogeneously dispersed in the fluid. Typical antifoaming agents include about 20% by weight of elemental Si, so that the treatment rate of the antifoaming agent may be in the range of about 5 to 500 ppm, preferably about 50 to 400 ppm in the finished oil. Diluent or carrier may be added to the antifoam at about 750 to about 1500 ppm, more preferably about 1030 ppm. Preferred diluents are Group 4 polyalphaolefin oils.

One method of treating an automatic transmission with ATF according to embodiments of the present disclosure includes a composition comprising a silicon-containing antifoaming agent having a kinematic viscosity at 25 ° C. of greater than about 20,000 centistokes in the presence or absence of diluent / carrier oil. Is added. The step of adding antifoam composition can be performed by direct injection into the transmission, for example by syringe, metering instrument or the like. In addition, the step may be performed at the following times: during initial construction of the transmission; At its initial installation into the vehicle; Every scheduled service period; At any time of service, maintenance or rebuild of the transmission; Upon any topping off, filling or recharging of the transmission with fluid; Etc.

For example, one method according to the present disclosure includes the following steps: (a) building a new automatic transmission, (b) charging the transmission using ATF, (c) performing a functional test on the transmission, (d) removing some (eg, half) ATF from the transmission, (e) adding a top treat composition containing a high viscosity silicon-containing antifoam to the partially filled transmission, and (f) transporting the transmission (Eg, for merchants, service points, vehicles, etc.), and (g) charging the transmission using ATF. The method may optionally include a step of installing the transmission to the vehicle after step (a).

Alternatively, rather than the treatment of high viscosity silicon-containing antifoams on the transmission (eg, top treatment of the transmission), the method according to the present disclosure also uses an initial or additional ATF to remove high viscosity silicon prior to filling or top distillation of the automatic transmission. Mixing step of containing antifoaming agent and ATF is included. The preliminary mixing of the antifoam with ATF can be carried out by adding the reagent directly to the ATF alone (with or without diluent / carrier) or by mixing a top treat additive system comprising a high viscosity defoamer with ATF. In any way, a fully formulated ATF is produced therewith the desired high viscosity defoamer. The ATF obtained is then used for filling, recharging or superdistillation removal of the automatic transmission, thereby increasing the surface tension of the fluid, thereby preventing a substantial increase in the 1-2 change time as the fluid ages.

According to the present disclosure, the step of adding a high viscosity defoamer to the transmission includes adding the reagent to the transmission case, sump, fluid pump, filling tube, dipstick, service port, torque converter, valve body, It should be noted that it may be added to the accumulator or hydraulically actuated line, or elsewhere that may include direct or indirect fluid interactions with the pump. The location where the high viscosity defoamer is added may be a suitable port in the pump / transmission hydraulic operation line near the transmission or at a certain point relatively far from the transmission, such as near the radiator / condenser / lubricator cooler.

Tests have shown that the use of fluids containing a high viscosity silicon-containing antifoaming agent results in the addition of an effective amount of a high viscosity silicon-containing antifoaming agent to the transmission relative to the gear change time for the aged fluid in an unlubricated transmission. It has been shown that it can be very effective for the maintenance and / or reduction of. Without being bound by theory, as shown in FIG. 1, it is believed that there is a linear relationship (line A) between the 1-2 fluctuation time of the transmission fluid and the surface tension of the transmission fluid. Additives for transmission fluids that are effective at maintaining relatively high fluid surface tensions can reduce the 1-2 shift time of the transmission during GMCT.

In order to measure the surface tension retention characteristics of various silicon-containing antifoams, various transmission oils containing different types and amounts of silicon-containing antifoams were pyrolyzed at 160 ° C. for 24 hours. The surface tension of the fresh and aged fluids was measured and the difference in surface tension was measured. Table 1 shows that compositions containing two different silicon-containing antifoams provide 2 and 8 ppm of silicon to the transmission fluid before and after aging.

Fluid number Si (ppm) Kinematic viscosity of antifoam (cSt) Surface tension of transmission fluid (dyne / cm) Difference New fluid Aged Fluid One 2 100 22.48 22.21 -0.27 2 8 100 22.21 21.91 -0.30 3 2 60,000 22.63 22.53 -0.10 4 8 60,000 22.59 22.50 -0.09

Fluids 3 and 4 with less change in surface tension as they age are expected to provide fluids that maintain high surface tension to provide shorter 1-2 fluctuation times as shown in FIG. 1. By comparison, fluids 1 and 2 are expected to provide an increase in 1-2 fluctuation times as the fluid ages due to a decrease in the surface tension of the fluid. As shown by the examples above, relatively low viscosity silicon-containing antifoams provide lower initial surface tension for transmission fluids (fluids 1 and 2) than the high viscosity silicon-containing antifoams used for fluids 3 and 4.

The example also shows that within the range tested, the amount of silicon-containing antifoam used in the transmission fluid has less influence on the change in surface tension than the viscosity of the silicon-containing antifoam. Thus, a relatively wide range of high viscosity silicon-containing antifoams can be used.

Conventional relatively low viscosity defoamers are used to reduce the surface tension of transmission fluid for foam reduction, while relatively high viscosity silicon-containing defoamers prevent or significantly reduce foaming initially occurring in the fluid by preventing or reducing air entrainment in the fluid. Maintain a relatively high surface tension to reduce. Nevertheless, the transmission fluid may contain both high and relatively low viscosity defoamers.

In addition, the test may maintain a lower increase in the total acid value (TAN) of the fluid during testing according to GMCT compared to a transmission comprising an effective amount of high viscosity silicon-containing antifoam in the transmission fluid. A schematic comparison of the increase in TAN for the transmission fluid during the GMCT circulation is shown graphically in FIG. 2. Curves 1 and 2 show rise in TAN for conventional transmission oils, while curves 3 and 4 show rise in TAN for transmission fluids containing high viscosity silicon-containing antifoaming agents according to the present disclosure.

Additive system

In one embodiment, the additive systems described herein include N-aliphatic alkyl substituted diethanolamines, phosphorylated and borated ashless dispersants, sulfurized fatty oil friction modifiers, copper corrosion inhibitors, high viscosity silicon-containing antifoams, nonylated diphenyl amines, alkyl sulfides Calcium hydroxide salt of phenate (TBN 150), octanoic acid, 3-decyloxypropylamine, ethylene oxide-propylene oxide (EO-PO) block copolymer, alkyl polyoxyalkylene ether, acrylate polymer interface Active agents and diluent oils. The following additive system examples further illustrate aspects of the disclosed embodiments, but do not limit the disclosed embodiments.

Additive system

ingredient Weight% range N-aliphatic alkyl substituted diethanolamine 0.08 to 0.30 Phosphorylation and Borated Ashless Dispersant 2.5 to 5.0 Sulfide Fat Oil Friction Modifier 0.60 to 1.20 Copper corrosion inhibitor 0.02 to 0.10 High Viscosity Silicon-containing Antifoaming Agent 0.02 to 0.10 Nonylated Diphenyl Amine 0.15 to 0.45 Ca (OH) ₂ salt of sulfide alkyl phenate (TBN 150) 0.02 to 0.10 Octanoic acid 0.02 to 0.10 3-decyloxypropylamine 0.02 to 0.10 Ethylene Oxide-Propylene Oxide Block Copolymer 0.005 to 0.10 Alkyl polyoxyalkylene ethers 0.02 to 0.10 Acrylate polymer 0.015 to 0.060 Thinner oil More than 0.10

Completely Formulated ATF

A fully formulated composition for use contemplated by embodiments of the present disclosure may contain, in addition to the components listed above:

1. Borated and / or nonbored dispersants;

2. antioxidant compound;

3. seal swell composition (also referred to as agent);

4. friction modifier;

5. Extreme pressure / wear protection;

6. viscosity modifiers;

7. Pour point depressant;

8. Surfactant.

Examples of such components are well known to those skilled in the art, each amount being the amount commonly used in transmission applications.

air Release agent / Air entrainment additive

One or more air entrainment additives known may also be useful, but are not necessary for the fluids according to the present disclosure. When used, air entrainment additives are materials which allow or facilitate the release of air or other gases trapped or entrained by chemical and / or physical means from the fluid or mixture.

As used herein, preferred air entrainment additives include, for example, fluorinated components, silicone based components, acrylates, polyacrylates, or PMA based components, and a more preferred class of air entrainment controls useful in the disclosed embodiments. The additive is a fluorinated component. The air release agent is added to or added with the top treatment composition, the additive system described above, or directly to the ATF.

VI improver

Viscosity index (VI) improvers are useful in the formulations and methods of embodiments, including, but not limited to, polyacrylates, polymethacrylates, styrene / olefin copolymers, styrene diene copolymers, EP aerials One or more materials selected from the group consisting of copolymers or terpolymers, and combinations thereof. Preferred VI improvers are high shear stable polymethacrylate polymers or copolymers used, for example, at 15% by weight in fluid formulations.

Surfactant / Dispersant

Preferably, the compositions described herein comprise N-aliphatic alkyl substituted diethanolamine (herein referred to as member (i)), and the ratio of phosphorus to member (i) in the ashless dispersant is the weight of member (i) One or more oil soluble phosphorus-free ashless dispersants in which phosphorus is present in an amount ranging from about 0.1 to about 0.4 parts by weight per part; And / or at least one oil soluble boron-containing ashless present in which boron is present in an amount such that the ratio of boron to member (i) in the ashless dispersant ranges from about 0.05 to about 0.2 parts by weight per part by weight of member (i). It may contain a dispersant. Most preferably, the composition is present in phosphorus in an amount such that the ratio of phosphorus to member (i) in the ashless dispersant is in a range from about 0.15 to about 0.3 parts by weight per weight part of member (i), wherein the ashless At least one oil soluble phosphorus- and boron-containing such that boron is present in an amount such that the ratio of boron to member (i) in the dispersant ranges from about 0.15 to about 0.3 parts by weight per part by weight of member (i). Ashless dispersants may be included.

Such phosphorus- and / or boron-containing ashless dispersants include ashless dispersants with basic nitrogen and / or one or more hydroxyl groups in the molecule, such as succinimide dispersants, succinic acid ester dispersants, succinic acid ester-amide dispersants, manic base dispersants, hydro It can be formed by phosphorylating and / or borating a carbyl polyamine dispersant or a polymer polyamine dispersant.

Polyamine succinimides in which the succinate comprises a hydrocarbyl substitution having at least 30 carbon atoms are described, for example, in US Pat. 3,202,678; 3,202,678; 3,216,936; 3,216,936; 3,219,666; 3,254,025; 3,254,025; 3,272,746; And 4,234,435. Alkenyl succinimides can be prepared by conventional methods such as heating an alkenyl succinic anhydride, an acid, an acid-ester, an acid halide, or a lower alkyl ester with a polyamine comprising one or more primary amino groups. Alkenyl succinic anhydrides can be readily prepared by heating a mixture of olefins and maleic anhydride at about 180 ° C to 220 ° C. The olefins are preferably lower monoolefins such as polymers or copolymers such as ethylene, propylene, 1-butene, isobutene and the like. More preferred sources of alkenyl groups are derived from polyisobutenes having a GPC number average molecular weight of 10,000 or more, preferably in the range of about 500 to about 2,500, most preferably in the range of about 800 to about 1,200.

As used herein, the term “succinimide” is meant to include a finished reaction product between one or more polyamine reactants and a hydrogen substituted succinic acid or anhydride (or such as a succinic acylating agent), wherein the primary amino group And compounds which may have amide, amidine and / or salt linkages in addition to imide linkages of the type resulting from the reaction of the anhydride moiety.

Alkenyl succinic acid esters and diesters of polyhydric alcohols having 2 to 6 carbon atoms with 2 to 20 carbon atoms can be used in the preparation of phosphorus- and / or boron-containing ashless dispersants. Representative examples include US Pat. No. 3,331,776; 3,381,022; And 3,522,179. The alkenyl succinic moiety of the ester corresponds to the alkenyl succinic acid moiety of the succinimide described above.

Suitable alkenyl succinic ester-amides for the preparation of phosphorylated and / or borated ashless dispersants are described, for example, in US Pat. No. 3,184,474; 3,576,743; 3,576,743; 3,632,511; 3,632,511; 3,804,763; 3,804,763; 3,836,471; 3,836,471; 3,862,981; 3,862,981; 3,936,480; 3,948,800; 3,950,341; 3,950,341; 3,957,854; 3,957,855; 3,957,855; 3,991,098; 3,991,098; No. 4,071,548; And 4,173,540.

Hydrocarbyl polyamine dispersants which may be phosphorylated and / or borated are generally aliphatic or acyclic halides (or mixtures thereof) having an average of at least about 40 carbon atoms with one or more amines, preferably polyalkylene polyamines It is prepared by reacting. Examples of hydrocarbyl polyamine dispersants are described in US Pat. No. 3,275,554; 3,394,576; 3,438,757; 3,454,555; 3,454,555; 3,565,804; 3,565,804; 3,671,511; 3,671,511; And 3,821,302.

In general, hydrocarbyl-substituted polyamines are high molecular weight hydrocarbyl-N-substituted polyamines containing basic nitrogen in the molecule. Hydrocarbyl groups generally have a number average molecular weight in the range of about 750 to 10,000, more generally in the range of about 1,000 to 5,000, and are derived from suitable polyolefins. Preferred hydrocarbyl-substituted amines or polyamines are prepared from polyisobutenyl chloride and polyamines having from 2 to 12 amine nitrogen atoms and from 2 to about 40 carbon atoms.

Manniche polyamine dispersants that can be used to prepare phosphorylated and / or borated ashless dispersants generally include alkyl phenols with long-chain alkyl substituents on the ring and one or more aliphatic aldehydes (especially formaldehyde) containing from 1 to about 7 carbon atoms. And derivatives thereof), and reaction products of polyamines (especially polyalkylene polyamines). Illustrative Mannich condensation products, methods for their preparation are described in US Pat. No. 2,459,112; 2,962,442; 2,962,442; 2,984,550; 3,036,003; 3,036,003; 3,166,516; 3,236,770; 3,368,972; 3,368,972; 3,413,347; 3,413,347; 3,442,808; 3,442,808; 3,448,047; 3,454,497; 3,459,661; 3,459,661; 3,493,520; 3,493,520; 3,539,633; 3,539,633; 3,558,743; 3,558,743; 3,586,629; 3,586,629; 3,591,598; 3,591,598; 3,600,372; 3,600,372; 3,634,515; 3,634,515; 3,649,229; 3,697,574; 3,703,536; 4,076,384; 3,704,308; 3,725,277; 3,725,277; 3,725,480; 3,725,480; 3,726,882; 3,726,882; 3,736,357; 3,736,357; 3,751,365; 3,076,365; 3,756,953; 3,756,953; 3,793,202; 3,793,202; 3,798,165; 3,798,165; 3,798,247; 3,798,247; 3,803,039; 3,872,019; 3,904,595; 4,076,384; 3,957,746; 3,980,569; 3,980,569; 3,985,802; 3,985,802; No. 4,006,089; No. 4,011,380; 4,025,451; 4,058,468; No. 4,083,699; No. 4,090,854; No. 4,354,950; And 4,485,023.

Preferred hydrocarbon sources for the preparation of the Mannich polyamine dispersant are those derived from substantially saturated petroleum fractions and polymers of olefin polymers, preferably monoolefins having 2 to about 6 carbon atoms. The hydrocarbon source generally contains at least about 40, preferably at least about 50 carbon atoms and provides substantial oil solubility to the dispersant. Olefin polymers having a GPC number average molecular weight of about 600 to 5,000 are preferred for reasons of easy reactivity and low cost. However, larger molecular weight polymers can also be used. Particularly suitable hydrocarbon sources are isobutylene polymers.

Preferred Mannich base dispersants for this use are Mannich base ashless dispersants prepared by condensing about 1 mole fraction of a long chain hydrocarbon substituted phenol with about 1 to 2.5 moles of formaldehyde and about 0.5 to 2 moles of polyalkylene polyamine.

Polymeric polyamine dispersants suitable for the preparation of phosphorylated and / or borated ashless dispersants are polymers comprising basic amine groups and oil soluble groups (eg, pendant alkyl groups having at least about 8 carbon atoms). The materials are described as interpolymers made from various monomers such as decyl methacrylate, vinyl decyl ether or relatively high molecular weight olefins with aminoalkyl acrylates and aminoalkyl acrylamides. Examples of polymeric polyamine dispersants include US Pat. No. 3,329,658; 3,449,250; 3,449,250; 3,493,520; 3,493,520; 3,519,565; 3,666,730; 3,666,730; 3,687,849; 3,687,849; And 3,702,300.

Base oil

The base oil used in the automatic transmission fluid preparation according to the present disclosure may be any suitable natural or synthetic oil having the viscosity properties required for such use. Thus, the base oil may consist entirely of natural oils, such as mineral oils of suitable viscosity, or may consist entirely of synthetic oils, such as poly-alpha-olefin oligomers of suitable viscosity. Likewise, the base oil may be a blend of natural and synthetic base oils, provided that the blend has the necessary characteristics for use in the manufacture of automatic transmission fluids. Generally, the base oil has a kinematic viscosity in the range of 3 to 8 centistokes (sSt) at 100 ° C. Preferred base oils are Group III stock solutions. Preferred base oil viscosity is, for example, 3.8 cSt. In one embodiment, the individual viscosity of the base stock is 2.8 cSt and 4.3 cSt, respectively. The base stocks useful in the embodiments provided herein can include, but are not limited to those made by PetroCanada.

0.025 to 5% by weight of 2,5-dimercapto-1,3,4-thiadiazole (DMTD) or derivatives thereof relative to the weight of the lubricating composition on an oil-free basis are included in the oil of lubricating viscosity. Derivatives of DMTD are as follows:

a) 2-hydrocarbyldithio-5-mercapto-1,3,4-thiadiazole or 2,5-bis- (hydrocarbyl-dithio) -1,3,4-thiadiazole and Mixtures thereof;

b) carboxylic acid esters of DMTD;

c) condensation products of halogenated aliphatic monocarboxylic acids with DMTD;

d) reaction products of unsaturated cyclic hydrocarbons and unsaturated ketones with DMTD;

e) reaction products of aldehydes and diaryl amines with DMTD;

f) amine salts of DMTD;

g) dithiocarbamate derivatives of DMTD;

h) aldehydes and reaction products of alcohols or aromatic hydroxy compounds, and DMTD;

i) reaction products of aldehydes, mercaptans and DMTD;

j) 2-hydrocarbylthio-5-mercapto-1,3,4-thiadiazole;

k) combination product of an oil soluble dispersant and DMTD; And mixtures thereof.

Components a) to k) are described in US Pat. No. 4,612,129 and the patent references cited therein. These references are incorporated herein by reference. Preferred thiadiazoles for use in the compositions described herein are those presented in a), h) and k) above. 2,5-bis- (hydrocarbyldithio) -1,3,4-thiadiazole and its 1 substituted equivalent 2-hydrocarbylthio-5-mercapto-1,3,4-thiadiazole Commercially available as a mixture of the two compounds in a ratio of about 85% bis-hydrocarbyl to 15% monohydrocarbyl.

dyes

Dyestuffs may be added to the compositions described herein. When dye is added, the preferred level is about 0.005% to about 0.05% by weight of ATF.

Sealing Swelling agent

Depending on the base stock chosen, certain amounts of sealing swelling agent are required to meet OEM sealing compatibility conditions. The use of Group II, III and IV base oils in many cases requires the addition of a material to swell the seal. The material is selected from the general categories of oil soluble diesters, aromatic base oils and sulfones. Alkyl adipates are examples of soluble diesters that may be used. Most preferred for use herein are alkyl adipates which are used at treatment rates of 3 to 20%, more preferably 3 to 10% and most preferably 5%.

The compositions described herein are useful for lubricating and treating power transmissions. Also included herein are vehicles having transmissions treated with the compositions or methods as well as transmissions treated with the compositions or methods of the disclosed embodiments.

In another embodiment, a method of lubricating a transmission, a method of reducing foaming of transmission fluid, a method of reducing entrainment in transmission fluid by entrained bubble release assistance in the fluid, a method of treating an automatic transmission by direct addition of an antifoam composition to the transmission , And a method for reducing 1-2 shift time in an automatic transmission by addition to a transmission fluid of a composition described herein.

Accordingly, the present disclosure also relates to an automatic transmission comprising the ATF lubrication composition described herein, a transmission lubricated by the method described herein, and further to a vehicle comprising the automatic transmission.

Other embodiments of the present disclosure will be apparent to those skilled in the art in view of the details and practice of the disclosed embodiments. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the embodiments being indicated by the following claims, including their legally acceptable equivalents. The disclosed embodiments are capable of significant modifications in practice. Accordingly, the present disclosure is not limited to the specific examples presented above.

The patentee does not intend that any disclosed embodiment be made available to the public and may not exemptly agree to the scope of the claims to the extent of any disclosed modification or change, which may be considered as part of the disclosed embodiment on the basis of equivalents. will be.

In several places in this specification, references are provided by US patent numbers. All of the above cited documents are hereby incorporated in their entirety as if they were fully incorporated herein.

Singular expressions used throughout the specification and claims may mean one or more. Unless otherwise indicated, it will be understood that all numbers indicative of the amount, feature, such as molecular weight, percentage, reaction conditions, etc., as used in this specification and claims are variable in all cases by the term “about”. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and claims may vary depending upon the desired features sought to be obtained by the disclosed embodiments. At the very least, it is not intended to limit the application of the principle of equivalents to the scope of the claims, and each numerical parameter should at least be grasped by the application of general approximation techniques in terms of reported significant digits. Although the numerical ranges and parameters setting forth the broad scope of the disclosed embodiments are approximate, the numerical values set forth in the specific examples are reported as precisely as possible. However, any numerical value includes certain errors that are inevitably provided due to the standard deviation originally found in their respective test measurements.

According to the present invention, there is provided a power transmission fluid with improved features, a lubrication method of a transmission and a vehicle comprising said transmission fluid.

Claims (23)

A power transmission fluid containing a silicon-containing antifoaming agent having a kinematic viscosity at 25 ° C. of greater than 20,000 centistokes in an amount effective to provide a gear shift time of 0.75 seconds or less over the useful life of the transmission fluid. 2. The silicon-containing antifoaming agent of claim 1 wherein the silicon-containing antifoaming agent consists of fluorosilicone, polydimethylsiloxane, phenyl-methyl polysiloxane, linear siloxane, cyclic siloxane, branched siloxane, silicone polymers and copolymers, organosilicon copolymers, and mixtures thereof A fluid selected from the group. The fluid of claim 2 wherein the silicon-containing antifoaming agent contains a mixture of polydimethylsiloxane and fluorosilicone compound. The fluid of claim 1 further comprising an acrylate polymer antifoaming agent. The fluid of claim 4 wherein the acrylate polymer antifoaming agent is selected from the group consisting of polymethacrylates, polyacrylates, dispersant polymethacrylates, dispersant polyacrylates, and mixtures thereof. The fluid of claim 1 wherein the silicon-containing antifoaming agent has a kinematic viscosity at 25 ° C. in the range of 40,000 to 80,000 centistokes. 0.08 to 0.30% by weight of N-aliphatic alkyl substituted diethanolamine; 2.5 to 5.0 weight percent phosphorylated and borated ashless dispersant; 0.6 to 1.2 weight percent sulfurized fatty oil friction modifier; 0.02 to 0.10% by weight of a copper corrosion inhibitor; 0.02 to 0.10% of a silicon-containing antifoaming agent having a kinematic viscosity at 25 ° C. exceeding 20,000 centistokes; 0.15 to 0.45 weight percent nonylated diphenyl amine; 0.02 to 0.10% by weight of Ca (OH) ₂ salt of sulfide alkyl phenate (TBN 150); 0.02 to 0.10% by weight of octanoic acid; 0.02 to 0.10% by weight of 3-decyloxypropylamine; 0.005 to 0.10% by weight of ethylene oxide-propylene oxide block copolymer; 0.02 to 0.10% by weight of alkyl polyoxyalkylene ether; 0.015 to 0.060% by weight of acrylate polymer; Automatic transmission fluid containing more than 0.10% by weight of diluent oil. Automatic transmission fluid containing: a) oil of lubricating viscosity having a kinematic viscosity at 100 ° C. of 2 to 10 centistokes; b) a weight percent of 2,5-dimercapto-1,3,4-thiadiazole (DMTD) and / or derivatives or precursors thereof sufficient to provide antiwear characteristics; c) a silicon-containing antifoaming agent having a kinematic viscosity at 25 ° C. of greater than 20,000 centistokes; And d) acrylates, methacrylates, polyacrylates, polymethacrylates or copolymers or terpolymers thereof. 9. The silicon-containing antifoaming agent of claim 8 wherein the silicon-containing antifoaming agent consists of fluorosilicone, polydimethylsiloxane, phenyl-methyl polysiloxane, linear siloxane, cyclic siloxane, branched siloxane, silicone polymer and copolymer, organosilicon copolymer, and mixtures thereof A fluid selected from the group. 10. The fluid of claim 9 wherein the silicon-containing antifoaming agent contains a mixture of polydimethylsiloxane and fluorosilicone compound. An automatic transmission lubricated with lubricating oil containing the fluid of claim 1. 12. The automatic transmission according to claim 11, which is a continuously variable transmission. An automatic transmission lubricated with lubricating oil containing the automatic transmission fluid of claim 7. A method of treating an automatic transmission with a space between the drives, comprising directly injecting a fluid composition containing a silicon-containing antifoaming agent having a kinematic viscosity at 25 ° C. above 20,000 centistokes into the space between the drives in the automatic transmission. The method of claim 14, wherein the composition further contains a carrier oil. Lubricating the transmission with a fluid containing an oil having a kinematic viscosity at 100 ° C. of 2 to 10 centistokes and an effective amount of silicon-containing antifoaming agent having a kinematic viscosity at 25 ° C. of greater than 20,000 centistokes, wherein Smaller gear shift times in automatic transmissions with aging transmission fluid, where the gear shift time is reduced compared to the gear shift time for the aged fluid in the transmission containing a defoaming agent having a kinematic viscosity at 25 ° C. less than 20,000 centistokes. How to keep increasing. The method of claim 16, wherein the silicon-containing antifoaming agent has a kinematic viscosity at 25 ° C. in the range of 40,000 to 80,000 centistokes. Fluid in the automatic transmission to reduce the amount of air dissolved and / or dispersed in the automatic transmission fluid, comprising lubricating the transmission with a transmission fluid containing a silicon-containing defoamer having a kinematic viscosity at 25 ° C. above 20,000 centistokes. To maintain increased surface tension in automatic transmission fluids throughout its life. Comprising directly injecting a composition containing a silicon-containing defoamer having a kinematic viscosity at 25 ° C. above 20,000 centistokes, and an inert carrier oil, into the hydrocarbon oil used in the vehicle as transmission lubrication and power transmission fluid. How to reduce the foaming of oil. 20. The process of claim 19, wherein the silicon-containing antifoaming agent is selected from the group consisting of fluorosilicone, polydimethylsiloxane, phenyl-methyl polysiloxane, linear siloxane, cyclic siloxane, branched siloxane, silicone polymers and copolymers and organosilicon copolymers. . 21. The method of claim 20, wherein the injection is performed with a transmission case, sump, fluid pump, filling tube, dipstick, service port, torque converter, valve body, accumulator or hydraulic actuation line. How to be. A vehicle comprising a transmission lubricated with a lubricant containing the fluid of claim 1. 20. A vehicle lubricated by the method of any of claims 14, 16, 18 and 19.

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