High‐performance waterborne coatings based on epoxy‐acrylic‐graft‐copolymer‐modified polyurethane dispersions

Abstract

Polyurethane dispersions (PUDs) have been an active area of research since the early 1940s because of legislative restrictions on the use of organic solvents in conventional solvent-based products and also because PUDs exhibit almost the same high performance levels as solvent-borne polyurethanes. In the present study, properties of conventional waterborne PUDs are modified with epoxy-acrylic graft copolymer blocks. The epoxy-acrylic graft copolymers were first modified with ethylene diamine to give amine-terminated blocks which in turn reacted with isocyanate-terminated prepolymer (prepolymer mixing process) to give modified PUDs. Several experimental sets were prepared with varying compositions. The experimental sets were also prepared using conventional poly(ethylene glycol) blocks and ethylene diamine chain-extenders. The physico-chemical properties and film characteristics of the experimental sets show the dramatic improvement in important mechanical properties of PUDs due to grafting with epoxy-acrylic copolymer blocks.

Crosslinked polyurethane–epoxy hybrid emulsion with core–shell structure

“…19,20 Although precrosslinking can improve the properties of emulsion and cast film, high level of precrosslinking may not be easily introduced into waterborne urethane due to the high viscosity of prepolymers or the poor coalescence of formulated emulsion. 4,21,22 In addition, epoxy resin has been used to precrosslink polyurethane emulsion during or after film formation. 4,23 But the polymerization reaction proceeded smoothly, and the coagulum content was low only when the epoxy content was below 15 wt%.…”

Preparation of branched polyurethane curing agent by condensation polymerization and radical polymerization

“…The demand for eco-friendly coatings, like waterborne coatings [1,2], high solid coatings [3], UV curable coatings [4,5] and powder coatings [6], has increased rapidly. Environmental concerns were the major factors behind this shift, such as recycling or waste disposal at the end of their life circle, volatile organic solvent emissions.…”

Development of Green Waterborne UV-Curable Castor Oil-Based Urethane Acrylate Coatings: Preparation and Property Analysis

“…[1][2][3][4][5][6] Radiationcurable polyurethane dispersions (referred to as UV-PUDs) have benefited over the past few years from growing attention by the market recognizing their high-end performance and strong potential. Eco-friendly coatings, such as high-solids coatings, powder coatings, waterborne coatings, and UV-curable coatings, have been developed to replace conventional solvent-borne coatings, and have made their way into the market with success.…”