Conductivity control agent for cationic electrodeposition coating material and method of regulating electric conductivity of cationic electrodeposition coating material using the same

摘要

The present invention is intended to provide a technology preventing decrease in an electroconductivity or an throwing power of a cationic electrodeposition coating composition having a lower solid content and/or a lower ash content. Therefore, the present invention relates to: an electroconductivity-controlling agent used for a low solid content type cationic electrodeposition coating composition having 0.5 to 9.0 wt % of solid content of the coating composition, which agent includes an amino group-containing compound having 500 to 20000 of molecular weight and 200 to 500 mmol/100 g of amine value, to adjust an electroconductivity of the composition to 900 to 2000 muS/cm; a method for adjusting an electroconductivity of a cationic electrodeposition coating composition, which includes steps of: adding an electroconductivity-controlling agent to a low solid content type cationic electrodeposition coating composition having 0.5 to 9.0 wt % of solid content of the coating composition, and adjusting an electroconductivity of the cationic electrodeposition coating composition to 900 to 2000 muS/cm during the above step, wherein the electroconductivity-controlling agent includes an amino group-containing compound having 200 to 500 mmol/100 g of amine value; and the like.