Vinyl acetate-co-ethylene copolymers (VAE), available from Gantrade Corporation in powder form, are white, free-flowing, dry powders that are readily redispersed into water to re-form a stable emulsion. Sometimes called “solid latex,” VAE redispersible powders (RDPs) are easy to ship, store, handle, and dry-mix versus VAEs in an aqueous emulsion form. VAE RDPs account for the majority of the global market for redispersible polymer powders.
In addition to the general advantages in handling powders versus emulsions, formulators can dry-mix RDPs with other powders, such as cement, sand, or light aggregate, at a field site or manufacturing location. This dynamic can facilitate consistency and performance reliability. In cold weather environments, freeze-thaw protection is unnecessary.
Performance advantages of incorporating VAE RDPs in dry-mix formulations include improvements in workability after hydration, water retention, plasticity, and improved dispersion. The VAE resins are soft and flexible because of their relatively high ethylene contents. As a rheology modifier, VAE RDPs improve flex strength, crack resistance, adhesion, abrasion and impact resistance, as well as water repellency.
VAE RDPs are used as cement and plaster modifiers or as a binder resin for inorganic materials, such as gypsum and hydrated lime. Formulators also use VAE RDPs as the sole binder resin for construction adhesives. Oilfield operators use VAE powder as an additive in oil and gas well cementing operations to control fluid loss from the cement to the formation. Advantages of RDPs in these environments include freeze protection and transportation benefits.
Applications for VAE RDPs include the formulation of construction materials such as tile adhesives, grouts, finishing plasters, troweling compounds, repair mortars, thin set mortars, and sealing slurries. The dominant market for VAE RDPs is in the building and construction industry, where they are used to formulate dry-mix products. The amount of VAE-RDPs added to cements and plaster is about 2-10 percent, depending on the improvement of strength, impact resistance, adhesion, and water resistance required of the compound.
VAE compositions contain between 10 and 40 percent ethylene in the copolymer. Ethylene is a soft, hydrophobic monomer unit, functioning as an internal “plasticizing” moiety. In copolymers, ethylene effectively reduces the glass transition temperature (Tg) of the hard, polar vinyl acetate polymer. Thus, copolymers with Tgs ranging from +15 °C to -15 °C are achievable. By using ethylene monomer to adjust the Tg, the formulator does not require any external plasticizers and the modified materials exhibit improved flexibility and moisture resistance.
Redispersible powders are available from Gantrade Corporation in 25 Kg. multi-layer paper bags containing an inner plastic bag. We package the 25 Kg. bags in 450 Kg. carton boxes, each containing 18 units. Flexible jumbo bags are also available in both 550 Kg. and 600 Kg. sizes within a carton box. VAE RDPs absorb moisture and should be stored under dry and cool conditions to prevent caking.
Gantrade’s professional staff is ready to assist with your selection of VAE RDPs, ensuring that you match the right product to the performance requirements of your application. We can provide an application guide by product grade. Contact us today to get started.