| abstract |
PROBLEM TO BE SOLVED: To find a novel binder for wood coating, which is not cured with isocyanate and can avoid or eliminate the presence of a solvent as much as possible. SOLUTION: A drying oil and / or a semi-drying oil A is reacted with a low-molecular-weight hydroxy compound B having two or more hydroxyl groups to obtain, on average, at least one oil having at least one olefinic double bond. A compound AB comprising two fatty acid residues and at least one hydroxyl group is produced, and this compound AB is then combined with a high molecular weight polyol C, a compound D having at least two isocyanate-reactive groups and at least one acid group. A prepolymer having a mass fraction of unreacted isocyanate groups of 0.1 to 4% by reacting with a polyfunctional isocyanate E ABCDE is produced (the percentage values are based on the weight of the prepolymer), then the product is neutralized with a tertiary amine G and prepared by transferring the utilized product to the aqueous phase. Oxidation drying type aqueous polyurethane dispersion. |