Vinylite VYN, high molecular weight. This resin is used in dentures where good fatigue resistance, impact strength, and tensile strength are required. It contains 85 to 88 percent vinyl chloride.
Vinylite VYN, medium molecular weight. This resin is used in general molding and extending applications including sheets, rods, and tubes. Its vinyl chloride content averages 85 to 88 percent.
Vinylite VYN, low molecular weight. This resin is used in moldings, coated paper, lacquers, floor tile, phonograph records, and felt impregnation. It contains 85 to 88 percent vinyl chloride.
Vinylite VYC. This resin of low molecular weight is compatible with nitrocellulose and is used in lacquers and finishes for industrial applications. Lacquers from the Vinylites are called Vinyloids.
The Vinylites for molding are thermoplastic and shrink very little, making them applicable to large moldings. They may be used in extension processes such as tooth-brush preforms, pipe lining, and wall trim. Fillers and pigments may be added, although pigments containing iron and zinc have harmful effects on the stability of the resin. The fillers used are wood flour, mica, talc, and alpha cellulose. Fillers reduce the mechanical strength of the resin and lessen its resistance to water. Plasticizers, such as dibutyl phthalate or tricresyl phosphate, give a softer, more flexible resin. Resins from the copolymers resemble the cellulose derivatives in their molding characteristics, mechanical strength, and appearance.
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.