Hydrolytically stable urea-formaldehyde resins and process for manufacturing them
AssigneeBorden, Inc.
InventorJames H. Williams
Life of this patent
Estimating the term…
Abstract
A process for preparing a urea-formaldehyde base resin having a F/U molar ratio of 1.0:1-1.2:1, that is hydrolytically stable, which comprises adjusting a formaldehyde solution to a pH of 0.5-2.5, slowly charging urea to said formaldehyde solution while maintaining the temperature at 40.degree.-70.degree. C., neutralizing the reaction mixture after obtaining a Gardner viscosity in the range of T+-V+, then adding the final charge of urea and permitting equilibration.
Claims47
A process for preparing a urea-formaldehyde base resin having a F/U mole ratio of 1.0:1-1.2:1, that is hydrolytically stable, which comprises
- adjusting an aqueous formaldehyde solution to a pH of from about 0.5 to about 2.5,
- slowly charging urea to said formaldehyde solution while maintaining the temperature of the solution in the range from about 50.degree. to about 70.degree. C.,
- neutralizing the reaction mixture after attaining 2.9-3.1:1 mole ratio of formaldehyde to urea and a Gardner viscosity in the range of T+-V+ and then
- adding the final charge of urea to achieve the desired mole ratio.
A process for preparing a urea-formaldehyde base resin having a F/U mole ratio of 1.0:1-1.2:1, and that is hydrolytically stable, which comprises
- adjusting an aqueous formaldehyde solution containing from about 49.8% to about 50.2% formaldehyde to a pH of 0.5-2.5 using formic acid, hydrochloric acid, sulfuric acid or p-toluenesulfonic acid, or a mixture of two or more of them,
- slowly charging urea to said formaldehyde solution while maintaining the temperature of the solution at 50.degree.-70.degree. C. until a 2.9-3.0 mole ratio of formaldehyde to urea is obtained,
- neutralizing the reaction mixture to a pH of 7.2-7.5 after obtaining a Gardner viscosity in the range of T+-V+, using sodium hydroxide and/or triethanolamine, and
- adding the final charge of urea while maintaining the pH at 7.2-7.5 and stirring for at least long enough to permit equilibration.
A urea-formaldehyde liquid base resin comprising urea and formaldehyde in a mole ratio of 1.0:1-1.2:1, said resin containing essentially no free formaldehyde and said resin when cured containing substantially more methylene groups than methylene ether groups.
A urea-formaldehyde liquid base resin comprising 24.89 weight percent formaldehyde, 49.78 weight percent urea, 0.06 weight percent sulfuric acid, 0.05 weight percent sodium hydroxide, 0.33 weight percent triethanolamine, and the balance, water.
A process for preparing a amino-formaldehyde base resin having a F/U mole ratio of 1.0:1-1.2:1, and that is hydrolytically stable, which comprises
- adjusting an aqueous formaldehyde solution to a pH of from about 0.5 to about 2.5,
- slowly charging an amino compound to said formaldehyde solution while maintaining the temperature of the solution at 50.degree.-70.degree. C. until a 2.9-3.0 mole ratio of formaldehyde to the compound is obtained,
- neutralizing the reaction mixture to a pH of 7.2-7.5 after obtaining a Gardner viscosity in the range of T+-V+, and
- adding the final charge of the amino compound to achieve the desired mole ratio.
An amino-formaldehyde liquid base resin comprising an amino compound and formaldehyde in a mole ratio of 1.0:1-1.2:1, said resin containing essentially no free formaldehyde and said resin when cured containing substantially more methylene groups than methylene ether groups.
Dependencies are inferred from the claim text.