Plastisols are fluid forms of vinyl plastic molding and coating compounds which make a variety of unique molding processes available. Plastisols are 100% solids. Most plastisols used are low to medium viscosity materials (having a viscosity between 1000 and 10,000 centipoises at 2.5 rpm on the Brookfield Viscometer). Some PVC plastisols used in the textile screen printing industry have viscosities as high as 4 million cps. at 0.5 rpm. Properties will vary depending on the application the plastisol will be used for.
Plastisols are very versatile, offering numerous application and processing possibilities. Cured (or fused) plastisol has the same basic physical properties commonly associated with other vinyls: flexibility, toughness, outdoor stability, abrasion and chemical resistance. Plastisols can be custom formulated to fit your application and processing needs.
Plastisols are available in formulations of hardnesses ranging from the Shore D (very hard compounds) to Shore 00 (very soft-soft plastic worm types). Many different properties can be incorporated into plastisols. Some of the available properties are low temperature flexibility, non-marring, nonflammable, acid resistance, abraision resistance, slip, as well as many others.
Processing of PVC Plastisols:
'Cure' (or fusion) of plastisols is a physical change of the resin being solvated by the plasticizer on heating. The fusion process changes the plastisol from a liquid to a solid state and brings about ultimate physical properties. As complete fusion is reached clarity, surface gloss, tensile and tear strength reach their maximum. Fusion is completed at approximately 350 to 400°F. Usually processing is done between 350° and 500°F to speed heat transfer. The time required to reach fusion is a function of the temperature and thickness of the material. When the heating process is complete the material is cooled. Through this curing process the plastisol transforms from a liquid material to a solid material with good physical properties.