Aqueous metal quenching medium

Abstract

Aqueous metal quenching media comprising vinyllactam/acrylamide copolymers

1 . An aqueous metal quenching medium, comprising a copolymer comprising in polymerized form:
 (a) ≧0.1 and ≦70% by weight of a monomer (a) consisting of at least one acrylamide, methacrylamide, or both, of formula (I)
   CH 2 ═C(R 1 )—C(═O)—NR 2 R 3   (I);
 
   (b) ≧30 and ≦99.9% by weight of a monomer (b) consisting of at least one N-vinyllactam of formula (II)   
       
         
           
           
               
               
           
         
         and 
         (c) ≧0 and ≦50% by weight of a monomer (c) consisting of at least one further ethylenically unsaturated compound which is different from the monomer (a) and the monomer (b) 
         wherein 
         the total amount of the monomer (a) +the monomer (b) +the monomer (c) equals 100% by weight in copolymerized form, 
         R 1  to R 5  are each, independently of one another, hydrogen or a linear or branched, optionally substituted, C 1 -C 10 -alkyl radical, and 
         x is an integer from 2 to 8. 
       
     
     
         2 . The medium of  claim 1 , comprising a copolymer comprising in polymerized form:
 (a) ≧5 and ≦40% by weight of the monomer (a); and   (b) ≧60 and ≦95% by weight of the monomer (b).   
     
     
         3 . The medium of  claim 1 , wherein
 R 1 , R 4  and R 5  are each hydrogen,   x is an integer from 3 to 5, and   R 2  and R 3  are not both hydrogen.   
     
     
         4 . The medium of  claim 1 , wherein at least one of R 2  and R 3  is an unsubstituted C 2 -C 4 -alkyl radical. 
     
     
         5 . The medium of  claim 1 , wherein at least one of R 2  and R 3  is a tert-butyl radical or an isopropyl radical. 
     
     
         6 . The medium of  claim 1 , comprising a copolymer comprising in polymerized form the monomer (a) consisting of N-tert-butylacrylamide, N-isopropylacrylamide, or both. 
     
     
         7 . The medium of  claim 1 , wherein the copolymer has a Fikentscher K value of ≧30 and ≦150. 
     
     
         8 . The medium of  claim 1 , wherein a total amount of the copolymer is ≧0.1 and ≦10% by weight. 
     
     
         9 . A process for cooling a metal object, the process comprising contacting a metal object with the aqueous metal quenching medium of  claim 1 . 
     
     
         10 . An aqueous metal quenching bath, comprising the aqueous metal quenching medium of  claim 1 . 
     
     
         11 . The medium of  claim 2 , wherein
 R 1 , R 4  and R 5  are each hydrogen,   x is an integer from 3 to 5, and   R 2  and R 3  are not both hydrogen.   
     
     
         12 . The medium of  claim 2 , wherein at least one of R 2  and R 3  is an unsubstituted C 2 -C 4 -alkyl radical. 
     
     
         13 . The medium of  claim 3 , wherein at least one of R 2  and R 3  is an unsubstituted C 2 -C 4 -alkyl radical. 
     
     
         14 . The medium of  claim 2 , wherein at least one of R 2  and R 3  is a tert-butyl radical or an isopropyl radical. 
     
     
         15 . The medium of  claim 2 , comprising a copolymer comprising in polymerized form the monomer (a) consisting of N-tert-butylacrylamide, N-isopropylacrylamide, or both. 
     
     
         16 . The medium of  claim 2 , wherein the copolymer has a Fikentscher K value of ≧30 and ≦150. 
     
     
         17 . The of  claim 2 , wherein a total amount of the copolymer is ≧0.1 and ≦10% by weight. 
     
     
         18 . A process for cooling a metal object, the process comprising contacting a metal object with the aqueous metal quenching medium of  claim 2 . 
     
     
         19 . An aqueous metal quenching bath, comprising the aqueous metal quenching medium of  claim 2 .