| abstract |
The invention relates to processes for producing melamine-formaldehyde foams comprising the consecutive steps a) and b): a) heating a mixture comprising a melamine-formaldehyde precondensate, a curative and a blowing agent to foam up and crosslink said mixture, and b) tempering the foam obtained in step a), wherein it is essential to the present invention that - step a) utilizes a precondensate which has a melamine:formaldehyde molar ratio in the range from 1:2.1 to 1:3.9, and - which has a sulfite group content, based on the total weight of the melamine-formaldehyde precondensate, in the range from 0% to 1% by weight, and - said tempering in step b) is effected at a temperature in the range from 230 to 290°C, and also to melamine-formaldehyde foams obtainable according to the processes of the invention, and to uses thereof. |