In lacquers the Vinylites offer high resistance to water, oils, and chemicals. The drying of such lacquers is by evaporation rather than by oxidation. They are suitable for lining food containers, coating concrete, coating paper for bottle cap liners, and as a stiffener for box toes of shoes. Their most successful application at present is as an inside coating for beer cans. Floor tile containing these resins mixed with slate flour or other filler has good possibilities. _Polyvinyl chloride resins._—Vinyl chloride may be polymerized to give nonflammable resins of varying solubilities. The completely polymerized resin is practically insoluble at ordinary temperatures and is used as a rubber substitute. It is marketed as Koroseal by B. F. Goodrich Rubber Co., Akron, O. Compared with natural rubber, it has greater resistance to acids, alkalies, oils, and alcohol, more flexing life, better resistance to sunlight, water, and oxidation. Solutions of this resin marketed as Korolac are used in special types of varnishes. _Polyvinyl chloroacetate resins._—These resins known as Mowiliths are made in Germany. Application is largely for surface coating. Practically no information on this type is available. _Divinyl acetylene and synthetic rubber._—Two products closely related to those described above but probably not synthetic resins as defined for this discussion are divinyl acetylene, a synthetic drying oil, and Neoprene, a synthetic rubber. Acetylene, when passed into a solution of copper chloride and ammonium chloride, combines with itself. When two molecules of acetylene react monovinyl acetylene is formed, and when three molecules of acetylene react divinyl acetylene is formed. Monovinyl acetylene reacts with hydrochloric acid to give chloroprene, which is polymerized to synthetic rubber or Neoprene. Divinyl acetylene is a colorless liquid which darkens on exposure to light and which has an onionlike odor. When polymerized liquids are formed, then as the reaction progresses viscous products and finally insoluble, infusible, inert resins. By arresting the reaction before the gel point is reached, an amber colored heavy liquid, soluble in aromatic hydrocarbons, is obtained. Since divinyl acetylene will continue to polymerize at ordinary temperatures, this property is taken advantage of in using it as a basis for paints, under the name “synthetic drying oil.” Clear, amber films are obtained from solutions of this oil in solvent naphtha. Divinyl acetylene is quick drying, is many times more impervious to moisture than linseed oil, and is thermosetting. It is not attacked by solvents but is attacked by strong oxidizing agents, and the gelled material may ignite spontaneously.