Preparation of two-component waterborne semi-gloss polyurethane varnish

A waterborne semi-gloss polyurethane varnish was prepared by using waterborne hydroxyl acrylic resin emulsion and polyisocyanate curing agent provided by Bayer MaterialScience.The mixing proportion of two types of hydroxyl resins was ascertained by test as follows:48.00% Bayhydrol XP 2546 and 23.00% Bayhydrol XP 2542.The molar ratio of NCO to OH is 1.6.The relationship between the amount of matting agent and film luster was discussed.The semi-gloss polyurethane varnish prepared with 2.4wt% matting agent has high hardness,excellent wear and weather resistance,and low glossiness,presenting a good comprehensive performance.