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US 4,285,848 AGranted
Wood adhesive from phenol, formaldehyde, melamine and urea
AssigneeBorden, Inc.
InventorCharles H. Hickson
Life of this patent
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Abstract
Preparation of this adhesive is characterized by initial condensation of phenol and formaldehyde, which is followed by sequential condensation of melamine and then urea to produce a wood adhesive which passes the standard 6-cycle test.
Claims7
A wood adhesive composition prepared from phenol, formaldehyde, melamine, and urea in a molar proportion per 1 mole of phenol of between about 6 and 8.24 moles of formaldehyde, between about 1 and 1.6 moles of melamine, and between about 1.6 and 3.3 moles of urea, said composition prepared by the steps of:
- (a) charging said phenol and said formaldehyde into a reactor held under condensing and basic conditions;
- (b) adding said melamine to said reactor, and adjusting and maintaining condensing conditions to a pH of between about 8.5 and 9.5 at a temperature of between about 85.degree. and 100.degree. C. until all of said melamine is condensed indicated by the contents of said reactor being clear;
- and
- (c) adding said urea to said reactor and maintaining urea condensing conditions until the condensate product in said reactor has a water tolerance of between about 70% and 180%.
1 more element
Dependencies are inferred from the claim text.