Basf Aktiengesellschaft

Christof Schmidt-Hellerau

Guenther Matthias

Johann Mayer

Otto Grabowsky

Engelbert Weber

Aqueous aminoresin solutions for low-formaldehyde surface bonding, based on condensates of melamine, urea, phenol and formaldehyde having a molar ratio of from 1.4 to 1.8 moles of formaldehyde, from 0.04 mole to 0.1 mole of melamine and from 0.015 to 0.04 mole of phenol per mole of urea, relative to the total amount of the aminoresin, are obtainable by mixing

Aqueous aminoresin solutions for low-formaldehyde surface bonding

Woodworking materials having a lower subsequent formaldehyde emission can be prepared in an advantageous manner and with good resin reactivity and good strengths and swelling properties by mixing lignocellulose-containing particles, for example wood particles, with a curable binder based on curable aminoplast condensates and then pressing the mixture under the action of heat, a mixture A containing a water-compatible agent for binding formaldehyde being applied to or mixed with the particles before the latter are mixed with the curable binder, if the mixture A is an aqueous solution which has a pH of from 3.0 to 6.5 and contains (a) organic acids which attack wood only insignificantly, if at all, in an amount of more than 15% by weight, based on the solids content of the solution, preferably a mixture of aliphatic carboxylic acids of 4 to 10 carbon atoms, and (b) a formaldehyde-binding, nitrogen-containing compound, in particular urea.

Preparation of woodworking materials

Improvement of the cold adhesion of glue resins, particularly phenoplast and aminoplast wood glues, by the addition of small amounts of a ligninsulfonate.

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Ludwigshafen, Germany

Christof Schmidt-Hellerau