Rapid Prototyping involved creating a working model of various parts of the system at a very early stage, after a relatively short investigation. The method used in building it is usually quite informal, the most important factor being the speed with which the model is provided.
There are water-and solvent-based -- also called oil-based -- polyurethane varnishes. Water-based polyurethanes are more environmentally friendly and safer to use than solvent-based, but they are not as resistant to wear and tear as solvent-based products.
By replacing the polyester and polyether backbone in urethane acrylates with an acrylic backbone, this chemistry opens the door to more weatherable UV-curable coatings, with properties that approach two-component urethane systems.oisture-curable coatings with superior curing speed were prepared from M100, an acrylic polyol with mid-range hardness and OH functionality and IPDI. P60, a liquid acrylic polyol with an average of 2.4 OH groups per polymer chain, produced a slow curing urethane prepolymer.