Water-soluble lubricant

Abstract

A water-soluble lubricant including a cyclic compound (A) having a ring structure (a) including at least one substructure represented by the following formula (i) or (ii):in the above formula, * represents a binding site. The water-soluble lubricant is used in an aqueous metalworking fluid and in a method of metalworking.

1 . A water-soluble lubricant, comprising:
 a cyclic compound (A) having a ring structure (α) comprising a substructure of formula (i) or (ii):   
       
         
           
           
               
               
           
         
         where * represents a binding site. 
       
     
     
         2 . The water-soluble lubricant of  claim 1 , wherein the ring structure (α) comprises at least one selected from the group consisting of an acid anhydride structure and a lactone structure. 
     
     
         3 . The water-soluble lubricant of  claim 1 , wherein the ring structure (α) has 5 to 20 ring forming atoms. 
     
     
         4 . The water-soluble lubricant of  claim 1 , wherein the cyclic compound (A) comprises at least one selected from the group consisting of a cyclic compound (A1) having a ring structure (α1) of formula (a-1) and a cyclic compound (A2) having a ring structure (α2) of formula (a-2): 
       
         
           
           
               
               
           
         
         where the cyclic compound (A1) and the cyclic compound (A2) are optionally substituted by a substituent. 
       
     
     
         5 . The water-soluble lubricant of  claim 1 , wherein the water-soluble lubricant is classified as any of A1, A2 and A3 according to JIS K2241: 2017. 
     
     
         6 . The water-soluble lubricant of  claim 1 , wherein the water-soluble lubricant does not substantially comprise a phosphorus-containing compound. 
     
     
         7 . The water-soluble lubricant of  claim 1 , wherein a content of the cyclic compound (A) is 0.1 to 10.0% by mass based on a total mass of the water-soluble lubricant excluding water. 
     
     
         8 . The water-soluble lubricant of  claim 1 , further comprising:
 water.   
     
     
         9 - 11 . (canceled) 
     
     
         12 . An aqueous metalworking fluid, comprising:
 the water-soluble lubricant of  claim 1 ; and   water.   
     
     
         13 . A method of metalworking, comprising:
 processing a workpiece with the aqueous metalworking fluid of claim  12 .   
     
     
         14 . The method of  claim 13 , further comprising:
 treating the workpiece with a formed-in-place gasket after the processing.   
     
     
         15 . The water-soluble lubricant of  claim 1 , further comprising:
 a base oil.   
     
     
         16 . The water-soluble lubricant of  claim 15 , wherein the base oil has a kinematic viscosity at 40° C. of 2.0 to 150 mm 2 /s. 
     
     
         17 . The water-soluble lubricant of  claim 1 , further comprising:
 an amine compound.   
     
     
         18 . The water-soluble lubricant of  claim 16 , wherein the amine compound is at least one selected from the group consisting of an alkanolamine and an alicyclic amine. 
     
     
         19 . The water-soluble lubricant of  claim 1 , further comprising:
 a fatty acid.   
     
     
         20 . The water-soluble lubricant of  claim 1 , wherein the fatty acid is at least one selected from the group consisting of a saturated fatty acid, an unsaturated fatty acid, a hydroxy fatty acid, an aliphatic dicarboxylic acid, a dimer acid of fatty acid, and a polymerized fatty acid of hydroxy unsaturated fatty acid. 
     
     
         21 . The method of  claim 13 , wherein the processing is at least one selected from the group consisting of cutting, grinding, punching, polishing, spinning, drawing, and rolling.