| 摘要 |
PCT No. PCT/EP93/03045 Sec. 371 Date May 11, 1995 Sec. 102(e) Date May 11, 1995 PCT Filed Nov. 2, 1993 PCT Pub. No. WO94/11413 PCT Pub. Date May 26, 1994Aqueous polyurethane dispersions prepared in several stages by reacting A) aliphatic and/or aromatic di- and/or tri-isocyanates with B1) polyol mixtures containing dimer diols of 25 to 100% by weight of dimer diols and 0 to 75% by weight of other hydrophobic diols and/or polyols, the equivalent ratio of OH to NCO being 1:1.1 to 1:4, and simultaneously or subsequently with B2) chain-extending agents containing two terminal NCO-reactive groups, the chain-extending agents additionally containing either artionic or cationic groups or groups convertible into anionic or cationic groups by neutralization, the equivalent ratio of NCO-reactive groups to NCO groups theoretically still present after the reaction of A) with B1) being 1:0.9 to 1:4, and then optionally reacting C) the NCO groups theoretically still present in the polyurethanes after the reaction of A) with B1) and B2) with polyols containing at least three hydroxyl groups and/or amino alcohols containing at least two hydroxyl groups in an equivalent ratio of OH+amino groups to NCO of at least 3:1, and finally dispersing the polyurethanes obtained in water, the polyurethanes obtained being at least partly neutralized before or during dispersion where the chain extending agents B2) contain as additional groups those groups which are only converted into anionic or cationic groups by neutralization, are provided. Also provided is a process for the production of aqueous polyurethane dispersions and methods of using aqueous polyurethane dispersions so prepared as stoving lacquers.
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