TW364003B - Flexible, aqueous processable, photoimageable permanent coatings for printed circuits - Google Patents

Abstract

A coating composition flexible after curing and processable in aqueous photoimageable solution that provides a permanent coating to printed circuit, comprising: (a) co-adhesive system, including 2 to 50 wt% of at least one low molecular weight copolymer adhesive component having 3,000 to 15,000 molecular weight and 2 to 50 wt% of at least one structural unit containing carboxylic acid, and 50 to 98 wt% of at least one structural unit of the following formula A (wherein R1 is H, alkyl, phenyl or aryl; R2 is H, CH3, phenyl, aryl, -COOR3, -CONR4R5 or -CN; and R3, R4 and R5 are respectively H, alkyl or aryl, unsubstituted or substituted by one or more hydroxy, ester, keto, ether or thioether;) and 50 to 98 wt% of at least one adhesive component having high molecular weight of 40,000 to 500,000 and containing carboxylic copolymer with the following structural unit B (wherein R6 is H, alkyl, -CN, phenyl, alkylphenyl or aryl; R7 is phenyl, alkylphenyl, aryl, -COOR8 or -CONR4R5; R8 is H or alkyl;), and the alkyl contains 1 to 8 carbon atoms, in which the low molecular weight adhesive and the high molecular weight adhesive are present in the form of mixture of different compositions; (b) acrylated amino ethyl formate monopolymer component; (c) photoinitiator or photoinitiator system; and (d) block polyisocyanate.