TVERRBINDINGSMIDDEL FOR EPOKSYBELEGNINGSFILMER PAAFOERT VED KATODISK ELEKTROAVSETNING.

摘要

A process for the preparation of an epoxy cationic resin from an epoxy resin composition having terminal oxirane groups which includes the step of converting oxirane groups to cationic groups by reacting a nucleophile with at least some of the oxirane groups of the epoxy resin compos ition wherein an organic acid and water are added during some part of this conversion; characterized by using as the epoxy resin composition a blend of (I) at least one of (A) at least one epoxy-based resin prepared from a diglycidyl ether of a polyether polyol having an average epoxide equivalent weight of from 350 to 5,000; or (B) at least one epoxy-based cationic resin prepared from a diglycidyl ether of a polyether polyol having an average epoxide equivalent weight of from 350 to 5,000 which diglycidyl ether has been partially capped with a monofunctional capping agent; or (C) a combination of (A) and (B); and (II) at least one different epoxy-based resin; wherein at some time during preparation of the composition, the resins are converted to cationic resins whereby there is obtained a blend of cationic polyether epoxy-based resin and a different cationic epoxy-based resin; said blend comprising from 10 to 90 percent by weight of component (I) based on total cationic resin and wherein the blend of cationic resins has a charge density of from 0.2 to 0.6 milliequivalent of charge per gram of resin,