| 摘要 |
Urea-formaldehyde-butanol condensation products are storagestable and substantially non-self-condensing at room temperature when they have a weight average molecular weight less than 1,000 and consist essentially of urea units carrying on the average 0.2 to 0.6 aldehyde reactive H atoms, 0.6 to 1.0 formaldehyde bridge, 1.2 to 1.8 C4H9OCH3-substituent and 0 to 0.2 -CH2OH substituent per urea unit therein. They are made by reacting urea with 2.5 to 3 mols of CH2O in aqueous alkaline solution, and then reacting the product with 1.2 to 1.8 mols of butanol in the presence of an acid etherification catalyst with simultaneous vacuum distillation of water. They are useful as cross-linking agents for insolubilizing surfacecoating resins such as those of the cross-linkable alkyd and vinyl types. |
