Polyurethane is a synthetic material that is created by a polyaddition reaction which can take the form of a resin or plastic which will be rigid in nature. Alternatively, there are polyurethane rubbers that are inherently more flexible to the touch.
Polyurethanes lend themselves well for making molds and casts, thus opening up a wide range of possibilities. In general, they are offered as a two-component system which have to be mixed in the specified ratio. The mixing causes a chemical reaction to take place and the material will start solidifying till it takes a hard form. Certain inhibitors are available that can delay this set time, thus making the materials suitable for various applications.
Polyurethane decoded
The light weight of polyurethanes combined with the elasticity, durability and resistance properties renders this versatile product well suited to a variety of industrial and consumer applications. It can be subjected to a variety of molding and casting techniques, even to the extent of custom designing for specific purposes.
Keep in mind that polyurethane resin flows easily, making it easy to mix and work with. The viscosity also proves to be appropriate for shaping and casting as needed. However, the materials tend to capture air which will show up as unsightly bubbles on the surface of the cast. Therefore, deairing in a pressure pot is essential as this will squeeze the air to microscopic size and the cured rigidity will keep them from expanding once again.
Polyurethanes need special pigments for coloring as the regular paints will tend to crack or peel when applied on this material. The dyes can be painted, sprayed or even added intrinsically to the material itself.
Usage of polyurethanes
Making resin casts is as easy as mixing the components together and pouring the material into the mold. Using an appropriate release agent is a must here. The casting itself can be done in a number of ways.
In fact, resin casting is a very popular art form for creating varied kinds of artistic jewelry and other craft works. Even children enjoy experimenting with encapsulating leaves, flowers, buttons and other small items to create keychains, pendants, earrings and other keepsakes. This polymer material is also combined with certain powders to create faux metal, stone and wood castings.
The same resin can be used for professional encapsulation purposes apart from architectural restoration, transparent sealing and even model making. Polyurethane materials enjoy excellent patronage outside the art studio as well – from foams to coatings, adhesives, paints and more. Most of the household stuff and other items of daily usage are fashioned from such materials itself, be it bedding, furniture or footwear to automotives, refrigerators and freezers.
In sum, polyurethanes are versatile materials and in the resin form they are commonly used for resin casting in both art studios and commercial applications.