METHOD FOR PREPARING CAPPED POLYISOCYANATE CURING AGENT, AND CATIONIC RESIN COMPOSITION FOR ELECTRODEPOSITABLE COATING AND AN ELECTRODEPOSITABLE COATING COMPOSITION COMPRISING THE CURING AGENT

摘要

A method for preparing a capped polyisocyanate curing agent is provided to ensure low oven loss and excellent penetrability, thereby obtaining an electrodepositable coating composition with excellent film appearance and pinhole resistance. A method for preparing a capped polyisocyanate curing agent comprises (i) a step for manufacturing a tertiary amine compound containing a hydroxyl group by reacting a secondary amine having a hydroxyl group and a monoepoxy compound; and (ii) a step for reacting the tertiary amine compound with polyisocyanate. The secondary amine having a hydroxyl group is the alkanolamine of the chemical formula 1. In the chemical formula 1, R1 is C1-4 alkyl group and R2 is C1-10 alkyl or alkyl alcohol, C6-15 aryl or aryl alcohol, or their ester derivatives.