Sprayable Polyurethanes

The sprayable types of polyurethane are being used where large or awkwardly shaped surfaces require covering. Before the advent of these materials castable polyurethane were used, but either the moulds required were complicated and therefore expensive. Many of the applications therefore are not entirely new but the use of the sprayable materials has resulted in lower costs and more widespread use.

One example of successful use of sprayable polyurethane is the lining of vibrator finishing barrels. The barrel are filled with an abrasive substance and untrimmed forgings and casting with the object of deburring and polishing the metal parts. The whole action is very abrasive but the sprayed coating is giving a long useful life. A slide valve on a sand hopper is another proven application, as also is the lining of a cement mixing barrel. Other uses includes the covering of wear plates in shot-blast equipment, linings of earth dumper trucks, fertilizer hoppers and even ships’s propellers.

The process is also suitable for the covering of large rollers where the tooling cost for cast polyurethanes would be prohibitive. When spraying, the rollers only need supporting between centres and rotating slowly. Similarly, the sprayable materials offer a quick and economic method for the coating of long lengths of fabric.