Blocked polyisocyanate and coating composition containing the same

Abstract

Abstract PURPOSE:To obtain a blocked polyisocyanate improved in compatibility with polyol and heat stability by blocking the NCO groups of a specified isocyanurate polyisocyanate by reaction with an active hydrogen compound. CONSTITUTION:Hexamethylene diisocyanate (a) is trimerized in the presence of 10ppm-1.0%, based on component (a), catalyst at 20-160 deg.C and this reaction is stopped at a conversion <=25%. The product is purified by removing excessive component (a) to obtain an isocyanurate polyisocyanate (A) of a viscosity (at 25 deg.C in a state free of component (a) and solvent) <=1600cps, an isocyanurate cyclic trimer content >=60% and a uretedione dimer content <=10%. Component A is reacted with an active hydrogen compound, as a blocking agent, ion such an amount as to give an equivalent ratio of the NCO groups of component A to the active hydrogen atoms of component B of 0.9-1.0 to obtain a blocked polyisocyanate in which the NCO groups are blocked.

Inventors

• 👤 Kazuki Saka
• 👤 和樹 坂
• 👤 Kaoru Kamiyanagi
• 👤 薫 上柳
• 👤 Akira Udatsu
• 👤 宇田津　晃

Bibliographic Details