Abstract: An improved method for the preparation of particleboard wherein a cellulose-containing particulate material is provided with a urea formaldehyde resin bonding agent and thereafter shaped and hardened at an elevated temperature and pressure. The bonding agent used is a urea-formaldehyde resin solution additionally containing melamine in an amount of 1.0 and 10 percent by weight, relative to the total amount of resin solids. The molar ratio of formaldehyde to mole equivalents of amino groups in the bonding agent is in the range of between 0.500:1 and 0.575:1.

Abstract: Chipboard showing a strongly reduced formaldehyde-emission is prepared on the basis of cellulose-containing material with a urea-formaldehyde or urea-melamine-formaldehyde resin as a binder, wherein said binder contains 0.45 to 0.65 mole of formaldehyde per mole-equivalent of amino groups and to which between 2 and 20% by wt., relative to the resin, of a protein soluble or dispersible in the resin solution has been added. The resin preferably contains between 25 and 45% by wt. of melamine, relative to the combined amount of urea and melamine. The boards have good strength and weather resistance, and have a very low formaldehyde emission.