Low solvent, water-dilutable binders for air drying coating compositions

摘要

Water-dilutable binders for air drying coating compositions, the content of the auxiliary organic solvent being below 15% of the binder solids are described. The binders comprise the partial condensation products of (A) 30-70% by weight of a film forming fatty acid modified alkyl resin intermediate with an acid value of between 30 and 200 mg KOH/g, an intrinsic viscosity zeta A of from 4.5 to 8 ml/g and an oil length of from 5 to 60%, with (B) 70-30% by weight of a film forming fatty acid modified alkyl resin intermediate with an acid value of below 5 mg KOH/g, a hydroxyl value of from 50 to 300 mg KOH/g, an intrinsic viscosity zeta B of from 8 to 12 ml/g and an oil length of from 5 to 60%, the ratio between the intrinsic viscosities zeta B/ zeta A lying between 1.4 and 2.7. Solutions of the binders ready for application are obtained which have a high solids content.