Patent ID: 7741406

Claim:
A method of making a phenol-formaldehyde resin suitable for use in preparing a binder composition where a molar excess of formaldehyde (F) is reacted with a phenol component (P), the method comprising reacting formaldehyde (F) with the phenol component (P) under an alkaline condition in the presence of a sulfite source, the sulfite source being present in an amount to provide 0.02 to 0.6 mole sulfite per mole of phenol and wherein a first portion of formaldehyde, sufficient to establish a molar ratio of formaldehyde to phenol component of above about 0.8:1 but less than a molar excess of formaldehyde, is reacted with phenol in the presence of the sulfite source and then a second portion of formaldehyde is added to establish the molar excess of formaldehyde for further reaction.