has a hydroxyl group a compound having both an isocyanate group and carboxyl group are allowed to react in a solution of an organic solvent for example acetone etc to introduce a carboxyl group the carboxyl group is neutralized with ammonia or amines and after adding water to it the organic solvent is removed to obtain the desired carboxyl group containing water dispersed polyurethane paint in the above case the preferred polyisocyanate is a non yellowing aliphatic or alicyclic polyisocyanate in view of weatherability the carboxyl group containing water dispersed polyurethane paint is commercially available as suncure 776 suncure 895 suncure 11447 suncure 847 suncure 898 etc from sanker company in u s a as u coat uws 140 from sanyo chemical industries ltd as spensol l53 spensol l 54 spensol l 55 spensol l 56 etc from dainippon ink amp chemicals inc which can be suitably used independently or in combination all of the commercially available paint are transparent paints containing 25 to 35 by weight of a polyurethane resin colloidally dispersed in water by weight being based on the solid content of the paint the carbodiimide compounds which are used for the crosslinking agent of the water dispersed polyurethane paint have the following chemical formula the carbodiimide compound exhibits extremely strong reactivity with free carboxyl groups and reacts with carboxyl groups to form n acylurea this reaction is conducted as low as about 30 60 u00b0 c to crosslink polyurethane however since carboxyl groups form salts and are ionized in the water based paint the crosslinking reaction scarcely takes place and.