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.
Unlike commercial urethane acrylates that are based on polyether or polyester polyols, this new class of urethane oligomers is based on acrylic polyols. These new acrylic polyols are unique in that they produce low-viscosity, nongelling urethane prepolymers with isophorone diisocyanate.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.