Lubricating oil composition, lubrication method, and gear

Abstract

Provided are a lubricating oil composition excellent in anti-seizing properties and ant-wear properties, containing a base oil containing at least a mineral oil and a sulfur- and phosphorus-containing anti-wear agent, a mass ratio (S/P ratio) of a sulfur atom and a phosphorus atom contained in the composition being 7.5 or more and 16 or less; and a lubrication method and a gear each using the same.

1 : A lubricating oil composition, comprising:
 a base oil containing at least a mineral oil, and   a sulfur- and phosphorus-containing anti-wear agent,   wherein a mass ratio (S/P ratio) of a sulfur atom and a phosphorus atom contained in the composition is 7.5 or more and 16 or less.   
     
     
         2 : The lubricating oil composition according to  claim 1 , further comprising:
 at least one selected from the group consisting of a phosphoric acid ester, an amine salt thereof, and a polysulfide.   
     
     
         3 : The lubricating oil composition according to  claim 1 , wherein:
 the sulfur- and phosphorus-containing anti-wear agent is at least one selected from the group consisting of a compound represented by formula (1) and a compound represented by formula (2):   
       
         
           
           
               
               
           
         
         R 11  is a hydrogen atom, a hydroxy group, or a mercapto group; 
         R 12  and R 13  are each independently a hydroxy group, a mercapto group, —X 12 —R 14 , or —X 13 —R 15 —X 14 —R 16 , provided that at least one of R 12  and R 13  is —X 12 —R 14  or —X 13 —R 15 —X 14 —R 16 ; 
         X 11 , X 12 , X 13 , and X 14  are each independently an oxygen atom or a sulfur atom, provided that at least one of X 11 , X 12 , X 13 , and X 14  is a sulfur atom; 
         R 14  and R 16  are each independently a hydrocarbon group having 1 or more and 24 or less carbon atoms; 
         R 15  is a hydrocarbon group having 1 or more and 24 or less carbon atoms; 
         R 21 , R 22 , and R 24  are each independently a hydrogen atom or a hydrocarbon group having 1 or more and 24 or less carbon atoms; 
         R 23  is a hydrocarbon group having 1 or more and 24 or less carbon atoms; 
         R 25  is an organic group or a nitrogen-containing group; and 
         X 21 , X 22 , X 23 , and X 24  are each independently an oxygen atom or a sulfur atom, provided that at least one of X 21 , X 22 , X 23 , and X 24  is a sulfur atom. 
       
     
     
         4 : The lubricating oil composition according to  claim 3 , wherein:
 R 11  is a hydrogen atom or a hydroxy group;   R 12  and R 13  are each independently a hydroxy group or —X 13 —R 15 —X 14 —R 16 , provided that at least one of R 12  and R 13  is —X 13 —R 15 —X 14 —R 16 ; R 15  is a hydrocarbon group having 1 or more and 4 or less carbon atoms;   R 16  is a hydrocarbon group having 6 or more and 10 or less carbon atoms;   X 11  is an oxygen atom; and   X 13  and X 14  are each independently an oxygen atom or a sulfur atom, provided that at least one of X 13  and X 14  is a sulfur atom.   
     
     
         5 : The lubricating oil composition according to  claim 3 , wherein:
 R 21  and R 22  are each independently a hydrocarbon group having 1 or more and 6 or less carbon atoms;   R 23  is a hydrocarbon group having 1 or more and 4 or less carbon atoms;   R 24  is a hydrogen atom or a hydrocarbon group having 1 or more and 4 or less carbon atoms;   R 25  is a carboxy group, an acyloxy group having an alkyl group having 1 or more and 4 or less carbon atoms, or an alkyl ester group having an alkyl group having 1 or more and 4 or less carbon atoms;   X 21  and X 22  are each an oxygen atom; and   X 23  and X 24  are each a sulfur atom.   
     
     
         6 : The lubricating oil composition according to  claim 2 , wherein:
 the lubricating oil composition comprises at least one phosphoric acid ester selected from the group consisting of a compound represented by formula (3) and a compound represented by formula (4):   
       
         
           
           
               
               
           
         
         R 31  is a hydrocarbon group having 1 or more and 24 or less carbon atoms; 
         m 31  is 1, 2, or 3; 
         in the case where m 31  is 2 or 3, plural R 31 's may be the same as or different from each other; 
         R 41  is a hydrocarbon group having 1 or more and 24 or less carbon atoms; 
         m 41  is 1 or 2; and 
         in the case where m 41  is 2, plural R 41 's may be the same as or different from each other. 
       
     
     
         7 : The lubricating oil composition according to  claim 2 , wherein:
 the lubricating oil composition comprising at least one polysulfide selected from the group consisting of a compound represented by formula (5) and a compound represented by formula (6):   
       
         
           
           
               
               
           
         
         wherein, in the general formula (5), 
         R 51  and R 52  are each independently a hydrocarbon group having 1 or more and 24 or less carbon atoms; 
         m 51  is an integer of 2 or more and 10 or less; 
         R 61  and R 63  are each independently a hydrocarbon group having 1 or more and 24 or less carbon atoms; 
         R 62  is a hydrocarbon group having 1 or more and 24 or less carbon atoms; 
         m 61  and m 62  are each an integer of 1 or more and 10 or less; and 
         p 61  is an integer of 1 or more and 8 or less. 
       
     
     
         8 : The lubricating oil composition according to  claim 1 , further comprising:
 a succinimide-based dispersant.   
     
     
         9 : The lubricating oil composition according to  claim 1 , which has a 100° C. kinematic viscosity of 8 mm 2 /s or more and 12 mm 2 /s or less. 
     
     
         10 : The lubricating oil composition according to  claim 1 , which is adapted to function as a lubricating oil composition for gear oils. 
     
     
         11 : A lubrication method, comprising lubricating an article or a substance with a lubricating oil composition comprising:
 a base oil containing at least a mineral oil; and   a sulfur- and phosphorus-containing anti-wear agent,   wherein a mass ratio (S/P ratio) of a sulfur atom and a phosphorus atom contained in the composition is 7.5 or more and 16 or less.   
     
     
         12 : The lubrication method according to  claim 11 , comprising lubricating gears with the lubricating oil composition. 
     
     
         13 : A gear, comprising a lubricating oil composition comprising:
 a base oil containing at least a mineral oil; and   a sulfur- and phosphorus-containing anti-wear agent,   wherein a mass ratio (S/P ratio) of a sulfur atom and a phosphorus atom contained in the composition is 7.5 or more and 16 or less.