Patent ID: 6893579

Claim:
An insulating product comprising a mineral wool sized with a phenol-formaldehyde resin binder, wherein the binder comprises, as a mixture: 60 to 90 parts by weight of phenol-formaldehyde resol having a free formaldehyde content of less than or equal to 25% by weight with respect to the dry weight of resin and a free phenol content of less than or equal to 2.5% by weight with respect to the dry weight of resin, obtained by condensation in basic medium of phenol (P) and formaldehyde (F) in an F/P molar ratio of around 2.5 to 4, and wherein the phenol-formaldehyde resol has a water dilutability of greater than 500% and less than or equal to 1500%, as determined by neutralizing the resol with sulfuric acid; and 10 to 40 parts by weight of urea.