| 摘要 |
<p>PURPOSE:To prevent fill-in on a plate cylinder by using, as the binder, a water- base polyurethane resin obtd. by reacting an org. polyisocyanate with a polyester polyol, etc., neutralizing the reaction product, and subjecting the neutralization product to chain extension in water. CONSTITUTION:An isocyanate-terminated prepolymer having an average functionality of 1-2 is produced by reacting an org. polyisocyanate (e.g. hexamethylene diisocyanate), a polyester diol obtd. from a glycol component comprising a 5-10C branched alkanediol and a dicarboxylic acid component, a compd. having an anionic hydrophilic group and at least two active hydrogen atoms in the molecule (e.g. a dihydroxycarboxylic acid), a polymerization terminator (e.g. a monoalcohol), and, if necessary, a chain extender (e.g. butanediol or isophoronediamine). The prepolymer is neutralized and subjected to chain extension in water, if necessary, followed by removal of an org. solvent from the resultant product, providing a water-based polyurethane resin. The amt. of carboxyl groups as the anionic hydrophilic groups is pref. 1.0-7.0wt.% based on the resin.</p> |
