METHOD FOR PRODUCING OF WATERBORNE URETHANE BINDER AND PAINT COMPOSITION FOR ELECTROMAGNETIC SHIELDING CONTAINING THE WATERBORNE URETHANE BINDER

摘要

Provided are a method for preparing an aqueous urethane binder, and a paint composition for electromagnetic interference shielding containing the binder prepared by the method which is low in surface resistance, is excellent in adhesive strength and is environmentally friendly. The method comprises the steps of adding water to a prepolymer water dispersion; and controlling the content of a volatile organic compound to 5 g/L or less by vacuum distillation, to prepare an aqueous urethane binder. Preferably the prepolymer water dispersion is prepared by adding 20-25 parts by weight of polyoxypropylene glycol, 0.6-1.4 parts by weight of polyoxypropylene glycerin, 5-10 parts by weight of 2,4-toluene diisocyanate, 2.0-3.5 parts by weight of DMPA, 7.5-9.0 parts by weight of NMP, 1.0-3.0 triethylamine, 2.0-3.5 parts by weight of dibutyl tin dilaurate and water based on the weight of a urethane binder. The paint composition comprises 15-35 wt% of the aqueous urethane binder; 35-45 wt% of a silver powder; 0.01-0.09 wt% of a dispersant; 0.02-0.1 wt% of an antisettling agent; and 20-40 wt% of water.