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US 5,362,842 AGranted
Urea-formaldehyde resin composition and method of manufacture thereof
AssigneeGeorgia-Pacific Resins, Inc.
InventorsLarry R. Graves, Jay V. Mueller
Life of this patent
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Abstract
A urea-formaldehyde resin useful as a binder for making a variety of products, and of a method for making the resin. The resin is prepared by reacting formaldehyde, urea, triethanolamine, and optionally ammonia in a two-step process, first under alkaline conditions and then under acidic conditions. The urea-formaldehyde resin thus produced has good resistance to hydrolysis, cures quickly without smoking, and is characterized by low formaldehyde release.
Claims20
A method of preparing a urea-formaldehyde resin comprising:
- mixing formaldehyde, urea, triethanolamine and optionally ammonia reactants at an alkaline pH, heating the mixture to an elevated temperature for a time sufficient to obtain complete metholylation of the urea, the reactants being present in an amount of about 1.50 to 4.0 moles of formaldehyde, about 0.001 to 0.1 mole of triethanolamine, and about 0.0 to 0.5 mole ammonia, per mole of urea, and
- adding acid to lower the pH to within the range of about 4.9 to about 5.2 and adding urea until the molar formaldehyde to urea ratio is within the range of about 1.5:1 to about 2.5:1 and reacting for a time sufficient to reduce free formaldehyde to less than 2%.
A urea-formaldehyde resin prepared by a method comprising:
- mixing formaldehyde, urea, triethanolamine and optionally ammonia reactants at an alkaline pH, heating the mixture to an elevated temperature for a time sufficient to obtain complete metholylation of the urea, the reactants being present in an amount of about 1.50 to 4.0 moles of formaldehyde, about 0.001 to 0.1 mole of triethanolamine, and about 0.0 to 0.5 mole ammonia, per mole of urea, and
- adding acid to lower the pH to within the range of about 4.9 to about 5.2 and adding urea until the molar formaldehyde to urea ratio is within the range of about 1.5:1 to about 2.5:1 and reacting for a time sufficient to reduce free formaldehyde to less than 2%.
Dependencies are inferred from the claim text.