Abstract: The invention relates to a resin for the production of cellulose based products, such as particle boards. The resin is a condensation product of formaldehyde, urea and phenol and optionally melamine with a molar ratio of 1.4-0.8 moles of urea, 0.006-0.04 moles of phenol and 0-0.04 moles of melamine per mole formaldehyde. The invention also relates to a method of producing such a resin. According to the method a separately prepared cross-linking agent containing a co-condensate of phenol, formaldehyde and urea or containing a co-condensate of phenol and formaldehyde together with urea, is added to a pre-condensate of formaldehyde, urea and optionally melamine, whereafter the mixture is condensed. As an alternative the cross-linking agent can be added to a finished condensate of formaldehyde, urea and optionally melamine.The invention also relates to a method of manufacturing glued cellulose based products.

Abstract: The invention relates to a method for the production of a resin which is used for manufacturing of an adhesive for cellulose based products. According to the method 30-70% by weight of a urea phenol resin with a molar ratio of 1.4-0.6 moles or urea, 0.006-0.3 moles of phenol and 0-0.04 moles of melamine per mole formaldehyde, are mixed with 70-30% by weight of a melamine resin with a molar ratio formaldehyde: melamine of 1.7-2.4. The urea-phenol resin has been prepared by adding a cross-linking agent containing a co-condensate of phenol, formaldehyde and urea to a pre-condensate of formaldehyde, urea and optionally melamine and condensing under acid conditions.According to a further embodiment the cross-linking agent is added to a evaporated condensate of formaldehyde, urea and optionally melamine.