Cleaning-free activated resinous composition and method for surface mounting using the same

Abstract

Activated resinous composition contains, on the basis of epoxy resin being solid at a room temperature of 100 parts by weight, carboxylic acid compound of 1 to 10 parts by weight, hardening agent of 1 to 30 parts by weight, a hardening reaction initiation temperature of said hardening agent being 150° C. or higher, and solvent of 10 to 300 parts by weight.

1 . An activated resinous composition containing, on the basis of an epoxy resin being solid at a room temperature of 100 parts by weight, a carboxylic acid compound of 1 to 10 parts by weight, a hardening agent of 1 to 30 parts by weight, a hardening reaction initiation temperature of said hardening agent being 150° C. or higher, and a solvent of 10 to 300 parts by weight. 
     
     
         2 . An method for surface mounting comprising the steps of coating at least soldered surface of a printed wiring board with the activated resinous composition defined by  claim 1 , loading the printed wiring board with a part to be surface mounted, subjecting this to reflow soldering and heat hardening the coated resinous layer. 
     
     
         3 . The method for surface mounting defined by  claim 2  further including a step of drying and/or heating the coated resinous layer at a temperature corresponding to a softening point or higher but lower than the hardening reaction initiation temperature before the printed wiring board is loaded with the part to be surface mounted. 
     
     
         4 . The method for surface mounting defined by  claim 2  further including a step of filling and hardening underfill resin after the coated resinous layer has been heat hardened. 
     
     
         5 . The method for surface mounting defined by  claim 3  further including a step of filling and hardening underfill resin after the coated resinous layer has been heat hardened.