Lubricants That Decrease Micropitting for Industrial Gears

Abstract

The invention relates to an industrial gear formulation containing a high TBN overbased detergent that results in decreasing micropitting for industrial gears.

1 . An industrial lubricant composition comprising:
 (1) a high TBN overbased detergent,   (2) a sulfur containing component selected from the group consisting of a polysulfide such as an olefin sulfide, substituted thiadiazole or mixtures thereof,   (3) a demulsifier,   (4) an antifoam agent selected from the group consisting of silicone antifoaming agents and non-silicone antifoam agents,   (5) a phosphorus containing acid, salt or ester,   (6) an oil of lubricating viscosity, and   (7) optionally one or more performance additive selected from the group consisting of metal deactivators, detergents, borated dispersants, non-borated dispersants, viscosity index improvers, viscosity modifiers, antioxidants, corrosion inhibitors, pour point depressants, seal swelling agents which results in reduced micropitting for industrial gears and bearings.   
   
   
       2 . The composition of  claim 1  wherein the overbased detergent comprises oil soluble neutral and overbased salts of alkali or alkaline earth metals with sulfonic acids, carboxylic acids, organic phosphorus acids or mixtures thereof. 
   
   
       3 . The composition of  claim 1  wherein the overbased detergents comprise phenates; carboxylates; sulfonates; alkali earth metal, alkaline earth metal detergents; salicylates; salixarates; calixarates; saliginen; overbased calcium detergents; overbased detergents containing metals of Mg, Be, Sr, Na, Ca and K; or mixtures thereof. 
   
   
       4 . The composition of  claim 1  wherein the overbased detergents are present in the range of about 0.1% to about 10% by weight of the lubricant and wherein the TBN of the overbased detergent is at least 10. 
   
   
       5 . The composition of  claim 1  wherein the polysulfide comprises olefin sulfide, three or more sulfur atoms including oligomeric species that may have multiple mono- or di-sulfide likages within the same molecule, polysulfide molecules that are mixtures of tri- or tetra-sulfides, substituted thiadiazoles, 2-(N,N-dialkyldithiocarbamoyl)benzothiazoles, 2,5-bis(alkyl-dithio)-1,3,4-thiadiazoles, 1,3,4 thiadiazoles, 2,5-bis(tert-nonyldithio), 2,5-bis(N,N-dialkyldithiocarbamoyl)-1,3,4-thiadiazoles, 2-alkyldithio-5-mercapto thiadiazoles or mixtures thereof. 
   
   
       6 . The composition of  claim 1  wherein the sulfur containing component is used in the range of about 0.1% to about 5% of the lubricant. 
   
   
       7 . The composition of  claim 1  wherein the demulsifiers comprise derivatives of propylene oxide, ethylene oxide, polyoxyalkylene alcohols, alkyl amines, amino alcohols, diamines or polyamines reacted sequentially with ethylene oxide or substituted ethylene oxides, polyethylene glycols, polyethylene oxides, polypropylene oxides, ethylene oxide-propylene oxide, glycolic monooleate, an overbased calcium sulfonate different from the overbased detergent, or mixtures thereof. 
   
   
       8 . The composition of  claim 1  wherein the demulsifiers are used in the range of about 25 ppm to about 1000 ppm of the lubricant. 
   
   
       9 . The composition of  claim 1  wherein the foam inhibitors comprise copolymers of ethyl acrylate and 2-ethylhexylacrylate, vinyl acetate monomers, polyethylene glycols, polyethylene oxides, polypropylene oxides and (ethylene oxide-propylene oxide) polymers; silicones of polyacetates, silicones of dimethyl silicone, polysiloxanes, polyacrylates, poly ethyl acrylate, poly 2-ethylhexylacrylate, poly vinyl acetate, 2-ethylhexyl/ethyl acrylate copolymers, polydimethyl/siloxane or mixtures thereof. 
   
   
       10 . The composition of  claim 1  wherein the foam inhibitors are used in the range of about 25 ppm to about 1000 ppm. 
   
   
       11 . The composition of  claim 1  wherein the oil of lubricating viscosity is used in the range of about 70 wt % to about 99 wt % of the lubricant. 
   
   
       12 . The composition of  claim 1  wherein the phosphorus-containing acid, salt or ester comprise an ash-containing or ashless comprise:
 (1) a non-ionic phosphorus compound;   (2) an amine salt of a phosphorus compound;   (3) an ammonium salt of a phosphorus compound;   (4) a monovalent metal salt of a phosphorus compound, or   (5) mixtures thereof.   
   
   
       13 . The composition of  claim 12  wherein the phosphorus-containing acid, salt or ester comprises zinc dialkyldithiophosphate, zinc di-(amyl)dithiophosphate, zinc di-(1,3-dimethylbutyl)dithiophosphate, zinc di-(heptyl)dithiophosphate, zinc di-(octyl)dithiophosphate di-(2-ethylhexyl)dithiophosphate, zinc di-(nonyl)dithiophosphate, zinc di-(decyl)dithiophosphate, zinc di-(dodecyl)dithiophosphate, zinc di-(dodecylphenyl)dithiophosphate, zinc di-(heptylphenyl)dithiophosphate, dialkyldithiophosphoric acid esters and amine salts thereof; amine salts of phosphites; and amine salts of phosphorus-containing carboxylic esters, ethers, and amides; partially esterfied phosphoric acid; zinc dialkyldithiophosphate derived from mixtures of alcohols include those derived from (i) a mixture of amyl alcohol and isobutyl alcohol, (ii) 2-ethylhexyl alcohol and isopropyl alcohol, and (iii) 4-methyl-2-pentanol and isopropyl alcohol or mixtures thereof. 
   
   
       14 . The composition of  claim 1  wherein the phosphorus-containing acid, salt or ester is present in a range of about 0.01 wt % to about 5 wt % of the lubricant. 
   
   
       15 . The composition of  claim 1  wherein the other performance additive compounds present is in the range of about 0 wt % to about 20 wt % of the lubricant. 
   
   
       16 . A method for lubricating a variety of industrial gears and/or bearings comprising contacting the gear and/or bearing with a lubricant comprising
 (1) a high TBN overbased detergent,   (2) a sulfur containing component selected from the group consisting of a polysulfide and a substituted thiadiazole,   (3) a demulsifier,   (4) an antifoam agent selected from the group consisting of silicone antifoam agents and non-silicone antifoam agents,   (5) a phosphorus containing acid, salt or ester,   (6) an oil of lubricating viscosity, and   (7) optionally one or more performance additive selected from the group consisting of metal deactivators, detergents, borated dispersants, non-borated dispersants, viscosity index improvers, viscosity modifiers, antioxidants, corrosion inhibitors, pour point depressants, seal swelling agents or mixtures thereof.   
   
   
       17 . The method of  claim 16  wherein the composition is prepared by a method consisting of blending, in-line blending, mixing, dissolving, or mixtures thereof, the components of the lubricant with the oil of lubricating viscosity until the components are substantially or wholly dissolved at a temperature in the range of about 25° C. to about 90° C., and for a period of time in the range of 1 hour to about 10 hours. 
   
   
       18 . The method of  claim 16  wherein the composition is in the form of a concentrate and the concentrate is prepared by mixing substantially all of the components of the lubricant except a major amount of oil of lubricating viscosity to form a mixture by adding the components sequentially, separately or in combination. 
   
   
       19 . The use of the composition of  claim 1  for lubricating gears or 20 bearings. 
   
   
       20 . The composition of  claim 1  providing a lubricant that is capable of providing at least one acceptable protection against wear, scuffing, micropitting or combinations thereof for industrial gears or bearings.