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Feuchtebeständigkeit und Hydrolyseresistenz von Holz-zu-Holz-Bindungen in Spanplatten, hergestellt mit formaldehydarmen modifizierten Harnstoff-Formaldehydharzen unter Einsatz verschiedener Härtungsbeschleunigersysteme. Tl. 3: Eigenschaften von mit modifizierten Harnstoff-Formaldehydharzen -UF-Harze- hergestellten Spanplatten

 
: Kehr, E.; Riehl, G.; Hoferichter, E.; Roffael, E.; Dix, B.

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Holz als Roh- und Werkstoff 52 (1994), Nr.4, S.253-260
ISSN: 0018-3768
Deutsch
Zeitschriftenaufsatz
Fraunhofer WKI ()
catalyst system; modifikation of resin; particleboard; properties of boards; ureaformaldehyde resin

Abstract
One-layer particleboards (pine wood) were made using three different low-emission UFresins and various amounts of different catalysts (ammonium sulfate, ammonium nitrate, a mixture of ammonium sulfate and formic acid). Melamine formaldehyde resin, resorcinol, quebracho-tannin and diphenylmethane diisocyanate (PMDI) were used as modifiers. The investigations led to the following results: The use of ammonium nitrate as a catalyst led, compared with ammonium sulfate and the mixture from ammonium sulfate and formic acid, to higher mechanical properties and lower thickness swelling of the particleboards. Particleboards bonded with UF resin modified with melamine formaldehyde resin showed, compared with the other investigated modifications, higher resistance in dry state, in the wet state and after water soaking and redrying of the particleboards, and lower thickness swelling. Modification of the UF-resin with PMDI improved the physico-mechanical properties of the particleboards. Particleboa rds bonded with UF-resin modified with resorcinol showed the lowest formaldehyde release, though this modification has a negative effect on the physico-mechanical properties of the boards.

: http://publica.fraunhofer.de/dokumente/PX-14322.html