Cleaning of foundry molds

Abstract

The present invention relates to a method of disintegrating a foundry mold comprising sand and a polyurethane binder. The present invention further relates to a method of disintegrating a foundry mold by contacting it with a composition comprising at least one carboxylic acid amide and at least one tyalkanolamine.

1 . A method for disintegrating a foundry mold comprising sand and a polyurethane based binder comprising
 (i) contacting the foundry mold with a composition comprising
 (a) at least one carboxylic acid amide of general formula (I) 
   
       
         
           
           
               
               
           
         
          wherein 
          R 1  denotes linear or branched, unsubstituted or hydroxy substituted C 2 -C 22  alkyl 
          R 2  and R 3  independently of each other, denote H or linear or branched, unsubstituted or substituted C 1 -C 12  alkyl; and 
         (b) at least one alkanolamine of general formula (II) 
       
       
         
           
           
               
               
           
         
          wherein 
          AO is, identical or different, selected from the group consisting of CH 2 —CH 2 —O, CH(CH 3 )—CH 2 —O, CH 2 —CH(CH 3 )—O, CH(C 2 H 5 )—CH—O, C(CH 3 ) 2 —CH 2 —O, CHC(CH 3 ) 2 —O and CH 2 —CH(C 2 H 5 )—O, 
          m is 1, 2, 3, 4, 5, 6 or 7, and 
          x, y independently of one another are 0 or 1;
 to obtain a mixture of the sand and the polyurethane binder. 
 
       
     
     
         2 . The method according to  claim 1 , wherein the sand is selected from the group consisting of natural silica sand, clay, green sand, quartz sand, chromite sand, olivine sand, special sands, and zirconium sand. 
     
     
         3 . The method according to  claim 1 , wherein the polyurethane based binder comprises polyurethane, water glass, and at least one resin that is different from polyurethane. 
     
     
         4 . The method according to  claim 1 , wherein R 1  is selected from the group comprising of ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, isooctyl, isopropyl, isobutyl, isopentyl, isohexyl, isoheptyl, isononyl, isodecyl, 1-hydroxyethyl, 1-hydroxypropyl, 2-hydroxypropyl, 1-hydroxybutyl, 2-hydroxybutyl, 1-hydroxypentyl, 2-hydroxypentyl, 3-hydroxypentyl, 4-hydroxypentyl, 1-hydroxyhexyl, 2-hydroxyhexyl, 3-hydroxyhexyl, 4-hydroxyhexyl, and 5-hydroxyhexyl. 
     
     
         5 . The method according to  claim 1 , wherein R 2  and R 3  are methyl. 
     
     
         6 . The method according to  claim 1 , wherein m is 1, 2 or 3. 
     
     
         7 . The method according to  claim 1 , wherein x and y are 0. 
     
     
         8 . The method according to  claim 1 , wherein the at least one carboxylic acid amide of general formula (I) and the at least one alkanolamine of general formula (II) are present in a molar ratio of 5:1 to 1:5. 
     
     
         9 . The method according to  claim 1 , further comprising
 (ii) separating the sand from the mixture obtained in step (i).   
     
     
         10 . The method according to  claim 1 , further comprising the step of
 (iii) drying the sand obtained in step (ii).   
     
     
         11 . The method according to  claim 1 , wherein the composition comprises at least one surfactant. 
     
     
         12 . The method according to  claim 11 , wherein the at least one surfactant is a non-ionic surfactant. 
     
     
         13 . The method according to  claim 12 , wherein the non-ionic surfactant is selected from the group consisting of poly(C 2 -C 4 )alkylene glycol mono-(C 8 -C 22 )-alkyl ether, poly(C 2 -C 4 )alkylene glycol mono-(C 8 -C 22 )-carboxylic acid ester, alkoxylated oil, and alkoxylated alkylamine. 
     
     
         14 . A composition comprising
 (a) 2-hydroxypropanamide; and   (b) monoethanolamine.   
     
     
         15 . The composition according to  claim 14  for use in disintegrating a foundry mold. 
     
     
         16 . A method for disintegrating a foundry mold comprising sand and a polyurethane based binder comprising contacting the foundry mold with a composition of  claim 14  to obtain a mixture of the sand and the polyurethane binder.