Vinyl Coatings

Most vinyl coatings consist of a resin made up of a copolymer of polyvinyl chloride (PVC) and polyvinyl acetate (PVA) in the ratio of 85 to 88 percent PVC to 12 to 15 percent PVA. Vinyl coatings have excellent flexibility and resist abrasion, water, acids, and alkalis. Vinyl coatings are, however, susceptible to strong solvents. Most of vinyl coatings except for the water-based vinyl formulations are not VOC compliant due to the large amounts of solvent required to dissolve vinyl resins.

Polyvinyl Butyral Wash Primers
Polyvinyl butyral (PVB) wash primers are used as a pretreatment to provide good adhesion to a variety of surfaces including stainless steel, carbon steel, zinc, tin, aluminum, and galvanized steel among others. These wash primers are effective at inhibiting underfilm corrosion in applications where exposure to salt water or salt spray is likely. Basic zinc chromate and vinyl butyral wash primers formulated in accordance with DOD-P-15382D have been used extensively. To achieve highest performance, wash primers should be topcoated with a coating based on a hydroxyl modified vinyl solution resin. This type of coating system is extremely effective in seawater and freshwater immersion exposures. VOC content of vinyl wash primers ranges in value from 680 to 765 g/L (5.7 to 6.4 lb/gal).

Polyvinyl Chloride-Polyvinyl Acetate Copolymers
Polyvinyl chloride-polyvinyl acetate (PVC-PVA) copolymer solution coatings are known for excellent mechanical properties, high toughness, and water resistance. These coatings dry rapidly by solvent evaporation to form extremely durable coatings suitable for use in marine or corrosive environments. PVC-PVA coatings are generally low in solids; as a result each sprayed coat may yield only about 1 mil dry film thickness. These coatings have the added advantage of drying rapidly enough that several coatings can be applied in a 24-hour period. The Navy has used these coatings for antifouling applications. The applicable specification is MIL-PRF-24647 (QPL 24647). PVC-PVA copolymer coatings range in VOC content from 540 to 650 g/L (4.5 to 5.4 lb/gal).

Waterborne Vinyl
Water-based vinyl coatings that consist of polyvinyl acetate are formulated for interior use. Coatings based on polyvinyl acetate have poor moisture resistance, light fastness, and exterior durability and as such are only suited for interior use.