Patent ID: 11548817

Abstract:
A method for the manufacture of mineral wool, is disclosed. In one example, the method comprises reacting an aqueous phenol-formaldehyde resole with free formaldehyde with a first amount of urea, thereby preparing a prereact; contacting the prereact with a second amount of urea; applying the resulting mixture of prereact and second amount of urea, as part of a binder, optionally with additives, to the surface of mineral fibers; and curing the binder on the surface of the mineral fibers. The total amount of urea used ranges 10-40 wt. % relative to the sum of the dry weight of the phenol-formaldehyde resole and the total amount of urea, and the second amount of urea used is at least 40 wt.-% of the total amount of urea. The invention also relates to a mineral wool product with reduced emissions of formaldehyde obtained by the method.