METHOD OF PREPARING UREA-FORMALDEHYDE-RESIN-BASED ADHESIVES

1. Method for preparing urea-formaldehyde resin based adhesives for gaining wood material having an extremely low formaldehyde emission, by an intermediate product forming condensation of urea and formaldehyde in the molar ratio of 1:1,8 to 1:2,1 at temperatures of 373 to 414 degrees K and conversio...

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Hauptverfasser:	WINTER, HARALD, MITTAG, LISA, OEHLER, KURT, KUNATH, GERHARD, BARSE, JOACHIM, DRECHSEL, HENRY, RAUE, GUDRUN, ULRICH, KATERINA, PETZ, ANNELIES, MULLER, HEINZ, FINDEISEN, GERHARD, HAMMER, LOTHAR, ESSER, GERHARD, PEINZE, KONRAD, STEINKE, ULRICH, NEUMANN, RAINER
Format:	Patent
Sprache:	eng ; ger
Schlagworte:	ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE ADHESIVES CHEMISTRY COMPOSITIONS BASED THEREON COMPOSITIONS OF MACROMOLECULAR COMPOUNDS DYES MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONSONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS METALLURGY MISCELLANEOUS APPLICATIONS OF MATERIALS MISCELLANEOUS COMPOSITIONS NATURAL RESINS NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL ORGANIC MACROMOLECULAR COMPOUNDS PAINTS POLISHES THEIR PREPARATION OR CHEMICAL WORKING-UP USE OF INORGANIC OR NON-MACROMOLECULAR ORGANIC SUBSTANCES ASCOMPOUNDING INGREDIENTS USE OF MATERIALS AS ADHESIVES
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Zusammenfassung:	1. Method for preparing urea-formaldehyde resin based adhesives for gaining wood material having an extremely low formaldehyde emission, by an intermediate product forming condensation of urea and formaldehyde in the molar ratio of 1:1,8 to 1:2,1 at temperatures of 373 to 414 degrees K and conversion of these condensates, in manner known per se, into adhesive resins, characterized in that one condenses urea and formaldehyde in aqueous solution in presence of 0,05 to 0,5% organic or anorganic acids, related to the amount of urea used, in maintaining a carbon dioxide pressure of 2 to 4.10**5 Pa that long until at least 40% of the formaldehyde used is bound in form of methylene bridges, and one further condenses this intermediate product in the neutral or low alkalic range after addition of urea up to a molar ratio of urea related to formaldehyde of 1:0,9 to 1:1,3 and, if desired, concentrates simultaneously.