Shaped articles of melamine/formaldehyde foams having low formaldehyde emission

Abstract

Shaped articles of melamine/formaldehyde foam have a formaldehyde emission of less than 0.1 ppm, determined according to DIN 55666, and are obtainable by the following process: a) a foam is prepared from a melamine/formaldehyde precondensate having a molar melamine:formaldehyde ratio greater than 0.5, b) the foam obtained is annealed at below 200° C., and c) the annealed foam is molded in a press at from 160 to 240° C. and an absolute pressure from 5 to 100 bar in the course of from 15 to 120 seconds to give the shaped article.

1 . A shaped article of melamine/formaldehyde foam, which shaped article has a formaldehyde emission of less than 0.1 ppm, determined according to DIN 55666, and is obtainable by the following process: 
 a) a foam is prepared from a melamine/formaldehyde precondensate having a molar melamine: formaldehyde ratio greater than 0.5,    b) the foam obtained is annealed at below 200° C., and    c) the annealed foam is molded in a press at from 160 to 240° C. and an absolute pressure of from 5 to 100 bar in the course of from 15 to 120 seconds to give the shaped article.    
     
     
         2 . A shaped article as claimed in  claim 1 , which, after the molding (step c),  
     
     
         3 . A shaped article as claimed in  claim 1 , wherein one or more surfaces of the shaped article are laminated with a hydrophobic or oleophobic textile layer.  
     
     
         4 . A process for the production of a shaped article of melamine/formaldehyde foam, comprising the following steps: 
 a) a foam is prepared from a melamine/formaldehyde precondensate having a molar melamine:formaldehyde ratio greater than 0.5,    b) the foam obtained is annealed at below 200° C., and    c) the annealed foam is molded in a press at from 160 to 240° C. and an absolute pressure of from 5 to 100 bar in the course of from 15 to 120 seconds to give the shaped article.    
     
     
         5 . A process as claimed in  claim 4 , wherein, after the molding (step c), d) the shaped article is stored at above 180° C. for at least 30 minutes.  
     
     
         6 . A melamine/formaldehyde foam having a formaldehyde emission of less than 0.1 ppm, obtainable from melamine/formaldehyde precondensate having a molar melamine: formaldehyde ratio of greater than 0.5 and subsequent annealing at a temperature of below 200° C.