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Phenol-urea/melamine-formaldehyde copolymer for use as adhesive or binder, e.g. for abrasives, made by combined condensation of separate precondensates in presence of anionic and cationic ion exchange resins.
: Schmidt, K.; Grunwald, D.; Miertzsch, H.

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DE 2003-10308792 A: 20030228
EP 2004-715250 AW: 20040227
WO 2004-DE372 A: 20040227
EP 1597294 A1: 20051123
Patent, Elektronische Publikation
Fraunhofer WKI ()

WO2004076514 A UPAB: 20041015 NOVELTY - Phenol-urea/melamine-formaldehyde copolymers, obtained by combined condensation of separate aqueous precondensates (phenol-formaldehyde and urea/melamine-formaldehyde) in presence of immobilised catalysts which can generate hydrogen ions and hydroxide ions. DETAILED DESCRIPTION - Copolymers (I), obtained by a first condensation of (a) an aqueous precondensate of phenol and/or phenol derivatives(s) (P) and formaldehyde or a formaldehyde derivative (F) and (b) an aqueous precondensate of urea and/or urea derivative(s) (U) and/or melamine and/or melamine derivative(s) (M) with (F), in presence of (c) an immobilised catalyst which can generate hydrogen ions (H+) and an immobilised catalyst which can generate hydroxide ions (OH-) or an immobilised catalyst which can generate H+ and OH- ions. An INDEPENDENT CLAIM is also included for a method for the production of (I) by condensation of an aqueous mixture containing (P) and/or (U) and/or (M) and (F) in presence of an anionic ion exchange resin (AE) and a cationic ion exchange resin (CE). USE - For the production or further processing of wood or timber products, as an adhesive, glue or foundry auxiliary material, as a binder in abrasive wheels, as a binder in insulating materials, for the production of expanded resins and as an infiltration and impregnating resin (claimed). ADVANTAGE - Copolymers of phenol, urea and/or melamine with formaldehyde in which all monomers are incorporated into the adhesive matrix as completely as possible; these copolymers show minimal or undetectable monomer contents (e.g. by GPC and 13C-NMR analysis) and there is little or no latent acid (as anions) or alkali in the adhesive or in hardened adhesive joints. The use of immobilised catalysts facilitates control of the polycondensation reaction.