Polyvinyl Acetate (PVA) is a thermoplastic resin. It was discovered by German scientist Dr. Fritz Klatte in 1912. The most common applications are white household glues and latex based house paints and as a media for artists' paints. PVA is non-toxic and has broad application because it is easily dispersed in water. Polyvinyl acetate resins are used in the formulation of hot glues, sealing products, fabric finishes, printing inks and plastic woods.
Properties of PVA
PVA sets by water removal through evaporation or absorption into surrounding materials. The clear PVA resin results in a hard, strong bonding film that resists bond breakdown when contacted by water or petroleum products. PVA resins deliver high early tack, minimum bond lines and low application cost.
As a clear synthetic resin, PVA is has an advantage over other resinous adhesives. It is easy to apply, contains no flammable solvents and can be diluted with water. PVA does not require the addition of preservatives or fungicides. It is not affected by fungus or moulds and is slow to deteriorate. Because PVA emulsions decompose slowly over time they should not be stored for more than a year before use. Freezing destroys PVA emulsions so they must be stored in areas that prevent freezing.
PVA Protects Foods
Edible coatings are used in the food industries to preserve vegetables and fruits as they move from farms to markets. Scientists of the ARS Citrus Products Laboratories in Winter Haven, Florida have developed an edible PVA to coat agricultural products. It is more effective than the shellac commonly used to prevent fruit decay and cheaper to apply. PVA resins enhance the gloss of chewing gum, candy and baked goods.
PVA Protects Teeth
Polyvinyl acetate is used to make mouth and teeth guards for high contact sports like football, ice hockey and soccer. Mouth guards are heated in hot water until soft. The softened material is placed in the mouth of the wearer and bitten to produce a one-of-a-kind mouthpiece tailored to the individual. Moulded in place PVA mouth guards offer better protection than off-the-shelf mouth guards.
Multiple Viscosity of PVA
PVA can be produced in a viscosity from V1.5 to V60. This property makes PVA an excellent consolidator for treating organic archaeological materials. PVA coatings penetrate and preserve fragile items such as bone, wood and other fibrous materials.
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