Grease composition

Abstract

The present invention addresses a problem of providing a grease composition for a speed reducer and a speed increaser, excellent in both leakage prevention performance and energy transfer efficiency. The grease composition for a speed reducer and a speed increaser contains a base oil (A), and nanofibers (B) having a thickness (d) of 1 to 500 nm, wherein the nanofibers (B) are one or more selected from cellulose nanofibers (B1) and modified cellulose nanofibers (B2).

1 . A grease composition used for a speed reducer and a speed increaser, comprising: a base oil; and nanofibers having a thickness of 1 to 500 nm, wherein the nanofibers comprise one or more selected from the group consisting of cellulose nanofibers and modified cellulose nanofibers. 
     
     
         2 . The grease composition of  claim 1 , wherein the nanofibers are present at a concentration of 0.1 to 20% by mass based on the total mass of the grease composition. 
     
     
         3 . The grease composition of  claim 1 , further comprising an organic bentonite, and wherein the nanofibers comprise the cellulose nanofibers. 
     
     
         4 . The grease composition of  claim 3 , wherein the organic bentonite is present at a concentration of 0.01 to 15% by mass based on the total mass of the grease composition. 
     
     
         5 . The grease composition of  claim 3 , wherein a mass ratio of the cellulose nanofibers to the organic bentonite is 0.05 to 5.0. 
     
     
         6 . The grease composition of  claim 1 , wherein the base oil is a mixed base oil comprising a low-viscosity base oil having a kinematic viscosity at 40° C. of 5 to 150 mm 2 /s and a high-viscosity base oil having a kinematic viscosity at 40° C. of 200 to 1000 mm 2 /s. 
     
     
         7 . The grease composition of  claim 1 , wherein the grease composition has a worked penetration at 25° C. of 220 to 440. 
     
     
         8 . The grease composition of  claim 1 , wherein the grease composition is used in a food machine including a speed reducer or a food machine including a speed increaser. 
     
     
         9 . A lubrication method, comprising lubricating a lubricating portion of a speed reducer or a speed increaser with the grease composition of  claim 1 . 
     
     
         10 . A lubrication method, comprising lubricating a lubricating portion of a food machine including a speed reducer or a speed increaser with the grease composition of  claim 1 .