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 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.

Abstract: Hard and medium density board made of lignocellulosic fibers having a central layer with substantially higher concentration of set resin than both the outer layers of said board have as good strength properties as a corresponding board having said higher concentration of said resin throughout the thickness of the board. Said board is produced by introducing a thermosetting resin solution or a high resin content pulp into and evenly across the width of the central layer of the pulp or the wet lap to be pressed and heat treated, the pressing period being shortened as well as the press cycle. Said process can be carried out with an apparatus including a member to be inserted in the pulp slurry flow in the headbox of a board machine or in the flow on the moving continuous wire screen of the board machine comprising an element having nozzles or slits through which a thermosetting resin solution or a high resin content slurry can be brought to flow.