Patent ID: 6472469
Filing Date: 2002-10-29
Classification: C03C

Abstract:
A method of preparing a binder suitable for treating fiberglass comprising:(a) selecting an aqueous resin prepared by reacting phenol with formaldehyde wherein the mole ratio of formaldehyde to phenol is greater than 3.75:1 under alkaline conditions, and the aqueous resin contains about 10% to 16% free formaldehyde; (b) adding urea to the aqueous resin in an amount greater than 40 parts per 100 parts of resin solids and reacting to form a urea-extended phenolic binder, wherein free phenol present in the urea-extended phenolic binder is less than about 1% by weight of urea-extended phenolic binder and wherein essentially no ammonia is employed in either step (a) or (b).