Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Inorganic compound
Reexamination Certificate
1997-01-14
2001-06-26
Medley, Margaret (Department: 1714)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Inorganic compound
C508S185000, C508S189000, C508S198000, C508S273000, C252S075000
Reexamination Certificate
active
06251840
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention encompasses lubricating compositions for use in automatic transmission fluids, tractor hydraulic fluids, manual transmission fluids, continuously variable transmission fluids, wet brake and wet clutch fluids, hydraulic fluids and the like. The fluids encompass both lubricating and functional properties. The compositions embody sulfur and boron-containing components as well as antifoam agents in an oil of lubricating viscosity. The compositions reduce wear in the device in which they are used. Decreased air entrainment in the fluid results in reduced fluid compressibility which results in improved operational parameters of devices containing the fluids.
2. Related Art
Functional/lubricating fluids are well known. As manufacturers of devices containing these fluids change equipment designs and operational specifications for these devices, such as automatic transmissions, new lubricating formulations must be developed. Such new formulations result in lubricating compositions with improved operational standards.
U.S. Pat. No. 5,422,023 describes lubricant compositions alkyl substituted dimercaptothiodiazoles together with an alpha-olefin/malic ester copolymer in a lubricating oil.
U.S. Pat. No. 4,990,273 describes an antiwear additive for lubricating compositions which is the reaction product of 2,5-dimercapto-1,3,4-thiadiazole with an aldehyde and an amine.
U.S. Pat. No. 4,612,129 describes dimercapto-thiadiazole derivatives as corrosion inhibitors used in compositions containing a metal salt of a dithiocarbamic acid of formula R
1
(R
2
)N—CSSH and an oil soluble sulfurized organic compound.
U.S. Pat. No. 4,301,019 describes reacting mercapto-thiadiazole with hydroxyl-containing unsaturated esters, or their borated derivatives to yield products useful as friction reducing additives in lubricants.
U.S. Pat. No. 4,140,643 describes reacting an oil-soluble dispersant with a dimercapto-thiadiazole and subsequently reacting the intermediate thus formed with a carboxylic acid or anhydride. The compositions are useful dispersants, extreme pressure agents and inhibitors of copper activity.
U.S. Pat. No. 4,136,043 describes reacting an oil soluble dispersant and a dimercapto-thiadiazole at 100-250° C. until the reaction product will form a homogeneous blend with a lubricating oil.
European Patent Application publication number 0630 960 A1 discloses the use of dimercapto-thiadiazoles with a copolymer of methacrylate, methyl-methacrylate and an amine-based antioxidant.
European Patent Application publication number 0601266 A1 describes novel compounds prepared by reacting 2,5-dimercapto-1,3,4-thiadiazole, aldehydes, and aromatic amines and their use as antiwear and antioxidant agents in lubricating compositions.
SUMMARY OF THE INVENTION
This invention comprises a lubricating/functional fluid composition with improved antiwear, antifoaming and low temperature viscosity properties. The composition comprises
A. An oil of lubricating viscosity having a 100° C. kinematic viscosity of 2-10 cSt;
B. sufficient weight percent of 2,5-dimercapto-1,3,4-thiadiazole (DMTD) and/or derivatives thereof to provide the composition with acceptable antiwear properties; and
C. an antifoam agent.
The composition has a −40° C. Brookfield viscosity of less than 20,000 cP as determined by ASTM-D-2983. The composition, when evaluated according to ASTM tests for scuffing and air entrainment, demonstrates superior performance.
The composition, as well as containing sulfur contributed by the thiadiazoles, may contain boron as contributed by borated dispersants or other borated materials such as borated epoxides or mixtures thereof The composition may further contain phosphorus which may be contributed by phosphorus acid esters such as dibutyl hydrogen phosphite, diphenyl hydrogen phosphite, triphenyl phosphite and/or triphenyl thiophosphate.
DESCRIPTION OF PREFERRED EMBODIMENT
The lubricant and functional fluid compositions of the present invention are based on diverse oils of lubricating viscosity, including natural and synthetic lubricating oils and mixtures thereof. The lubricating compositions may be lubricating oils and greases useful in industrial applications and in automotive engines, transmissions and axles. These lubricating compositions are effective in a variety of applications including crankcase lubricating oils for spark-ignited and compression-ignited internal combustion engines, including automobile and truck engines, two-cycle engines, aviation piston engines, marine and low-load diesel engines, and the like. Also, automatic transmission fluids, transaxle lubricants, gear lubricants, metalworking lubricants, hydraulic fluids, and other lubricating oil and grease compositions can benefit from the incorporation of the compositions of this invention. The inventive functional fluids are particularly effective as automatic transmission fluids.
The lubricants and functional fluid compositions of this invention employ an oil of lubricating viscosity which is generally present in a major amount (i.e. an amount greater than about 50% by weight). Generally, the oil of lubricating viscosity is present in an amount of greater than about 80% by weight of the composition.
The natural oils useful in making the inventive lubricants and functional fluids include animal oils and vegetable oils (e.g., lard oil, castor oil) as well as mineral lubricating oils such as liquid petroleum oils and solvent treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinicnaphthenic types which may be further refined by hydrocracking and hydrofinishing processes and are dewaxed. Oils of lubricating viscosity derived from coal or shale are also useful. Synthetic lubricating oils include hydrocarbon oils and halo-substituted hydrocarbon oils such as polymerized and interpolymerized olefins (e.g., polybutylenes, polypropylenes, propylene-isobutylene copolymers, chlorinated polybutylenes, etc.); poly(1-hexenes), poly-(1-octenes), poly(1-decenes), etc. and mixtures thereof; alkyl-benzenes (e.g., dodecylbenzenes, tetradecylbenzenes, dinonylbenzenes, di-(2-ethylhexyl)-benzenes, etc.); polyphenyls (e.g., biphenyls, terphenyls, alkylated polyphenyls, etc.); alkylated diphenyl ethers and alkylated diphenyl sulfides and the derivatives, analogs and homologs thereof and the like.
Alkylene oxide polymers and interpolymers and derivatives thereof where the terminal hydroxyl groups have been modified by esterification, etherification, etc., constitute another class of known synthetic lubricating oils that can be used. These are exemplified by the oils prepared through polymerization of ethylene oxide or propylene oxide, the alkyl and aryl ethers of these polyoxyalkylene polymers (e.g., methyl-polyisopropylene glycol ether having an average molecular weight of about 1000, diphenyl ether of polyethylene glycol having a molecular weight of about 500-1000, diethyl ether of polypropylene glycol having a molecular weight of about 1000-1500, etc.) or mono- and polycarboxylic esters thereof, for example, the acetic acid esters, mixed C
3-8
fatty acid esters, or the C
13
Oxo acid diester of tetraethylene glycol.
Another suitable class of synthetic lubricating oils that can be used comprises the esters of dicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl succinic acids, alkenyl succinic acids, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl malonic acids, alkenyl malonic acids, etc.) with a variety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, 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 phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid dimer, the complex ester formed by reacting one
Murray Kathleen A.
Tipton Craig D.
Ward, Jr. William C.
Esposito Michael F.
Medley Margaret
Shold David M.
The Lubrizol Corporation
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