Radiation cured branched polyurethane for coatings

The purpose of this work is to develop flexible as well as rigid polyurethane coating by using mixed polyol. It is developed by using low cost reactant such as polyether and introducing branching in it.

Radiation curable branched polyurethanes were synthesised. In this work, branched polyol was synthesised by using trimethylol propane (TMP) and reacted with adipic acid (AA), neopentyl glycol (NPG) (polyester) and polypropylene glycol (PPG) (polyether). These branched polyols were developed by varying ratio of polyether to polyester from 20:80, 40:60 and 55:45. These branched polyols were further reacted with isophorane di isocyanate (IPDI) and hydroxy ethyl metha acrylate (HEMA) to get vinyl terminated prepolymer.

The branched polyol due to presence of polyether offers excellent flexibility and polyester which provides excellent scratch, adhesion, and tensile strength. Use of reactive diluents is avoided, and its role is compensated by polyether in all systems, which takes care of reducing viscosity and improves flow and levelling properties.

Synthesis of branched polyol using polyesters and polyethers is more beneficial as it offers advantage of its combined property.

The polyurethane acrylate due to its polyol combination, branching and cross linking offers enhanced coating properties and can be used for various coating applications.