Method of forming coated surfaces

摘要

The interior surface of a hollow article, including a pipe or tube, is coated by introducing polythene, cellulose acetate-butyrate, polystyrene or shellac in powder form into the interior of the preheated article, distributing the powder over the surface, e.g. by rotating or rocking, removing the surplus powder and continuing the heating until the coating material flows and forms a homogeneous smooth layer. The powder, which should pass a 60-mesh B.S. sieve, may be introduced by sprinkling or application through a sieve. A flame from a spray pistol may be used to supply the heating. More than one coating may be applied and the process may be effected in an inert atmosphere. Anti-oxidants, e.g. di-o-cresylol-propane and pigments, e.g. titanium dioxide, chrome yellow, cadmium red or cobalt blue may be added.