Lubricating oil for use in hot-rolling oil and method for manufacturing hot-rolled sheet

Abstract

A lubricating oil for use in hot-rolling oil for aluminum sheet, comprises: (a) a mineral oil having a kinematic viscosity of 80 mm 2 /second or less at 40° C.; (b) 1 to 14 mass % of a fatty acid having 10 to 22 carbon atoms; (c) 5 to 15 mass % of an oil and fat and/or a synthetic ester; (d) 5 to 10 mass % of a phosphorus-containing extreme-pressure agent; (e) 0.1 to 1 mass % of a polyoxyethylene alkyl amine; and 0.1 to 10 mass % of an organic acid salt of a copolymer composed of a (meth)acrylic acid salt, (meth)acrylamide, and at least one amine monomer, and the mass ratio of the component (c) to the component (d) (component (c)/component (d)) is 1/0.6 to 1/1. The lubricating oil for use in hot-rolling oil for aluminum sheet of the invention provides a high level of rolling lubricity, iron corrosion protection in a hot-rolling step and a rolled aluminum sheet with high sheet surface quality can be obtained.

1 . A lubricating oil for use in hot-rolling oil for aluminum sheet, comprising:
 (a) a mineral oil having a kinematic viscosity of 80 mm 2 /second or less at 40° C.;   (b) 1 to 14 mass % of a fatty acid having 10 to 22 carbon atoms;   (c) 5 to 15 mass % of an oil and fat, a synthetic ester or a combination thereof;   (d) 5 to 10 mass % of a phosphorus-containing extreme-pressure agent;   (e) 0.1 to 1 mass % of a polyoxyethylene alkyl amine; and   (f) 0.1 to 10 mass % of an organic acid salt of a copolymer having repeat units of a (meth)acrylic acid salt, (meth)acrylamide, and at least one amine monomer represented by formula (1):   
       
         
           
           
               
               
           
         
         wherein R 1  represents a hydrogen atom or a methyl group, R 2  and R 3  represent the same or different alkyl groups of 1 to 3 carbon atoms, A represents —NH—, and m represents an integer of 1 to 3, wherein 
         the organic acid salt of the copolymer has a weight average molecular weight of 10,000 to 1,000,000, 
         where an organic acid used to form the organic acid salt of the copolymer is represented by formula (2):
   R 4 COOH   (2),
 
 
         wherein R 4  represents an alkyl group of 1 to 5 carbon atoms, a hydroxyalkyl group of 1 to 5 carbon atoms, a carboxyalkyl group with an alkyl moiety of 1 to 5 carbon atoms, or a carboxyl group, and 
         the mass ratio of the component (c) to the component (d) (component (c)/component (d)) is 1/0.6 to 1/1. 
       
     
     
         2 . The lubricating oil for use in hot-rolling oil for aluminum sheet according to  claim 1 , wherein the component (c) is butyl stearate. 
     
     
         3 . An aluminum sheet hot-rolling oil, comprising the lubricating oil for use in hot-rolling oil according to  claim 1  and water. 
     
     
         4 . A method for manufacturing a hot-rolled sheet, comprising a hot-rolling an aluminum sheet in the presence of the aluminum sheet hot-rolling oil according to  claim 3 . 
     
     
         5 . An aluminum sheet hot-rolling oil, comprising the lubricating oil for use in hot-rolling oil according to  claim 2  and water. 
     
     
         6 . A method for manufacturing a hot-rolled sheet, comprising hot-rolling an aluminum sheet in the presence of the aluminum sheet hot-rolling oil according to  claim 5 .