Ethyl acrylate is a widely used acrylic monomer with excellent availability and commodity economics. The increase use of water based acrylic paints and costings, and the higher demand for acrylates in adhesives are driving the growth rate of EA monomer.
EA exhibits excellent copolymer characteristics with other acrylate and methacrylate monomers and vinyl acetate monomer. With a homopolymer Tg of -21°C. EA increases the softness, flexibility, and tack of copolymer compositions. It is often copolymerized with the softer butyl acrylate monomer to afford a slightly harder finish. In copolymers, EA contributes good weathering characteristics, UV stability, clarity, and oil resistance. The EA unit has a higher ester content (-CO2-; 42%) vs. other “soft” acrylic monomers like butyl acrylate (33%) and 2-ethylhexyl acrylate (27%). Hence it is more polar and improves adhesive and binding properties to polar surfaces.
The major applications for EA are in acrylic copolymers used in water-based adhesives, especially pressure sensitive adhesives (PSAs), and latex paints and coatings. It also has major uses in ethylene-co-EA copolymers (EEAs), which are thermoplastic elastomers. Other applications include ink binder resins, textile, leather and paper coatings.
Thermoplastic EEA copolymers generally contain about 15-30% EA comonomer. Applications included hot melt adhesives, tie-layers in multiple films and laminating, blown film for packaging and shrink wrap. EA copolymers comply with FDA regulations covering direct and indirect food contact applications.
Copolymers with (meth)acrylic acid are used in Alkali Soluble Emulsion (ASE) and Hydrophobically modified HASE rheology modifiers. Thickening is triggered by a change from a low to a high pH, where these rheology modifiers are steeply sheer thinning. HASEs are state-of-the-art rheology modifiers offering performance properties over a wider range of shear levels and affording a broader range of shear properties vs. their ASE counterparts. Gantrade offers a full range of ASE and HASE rheology modifiers.
EA is manufactured by the esterification of acrylic acid with ethyl alcohol. EA requires 0.72 lbs. of acrylic acid per pound of EA. Hence, EA is more dependent on the economics or acrylic acid compared to, for example, butyl acrylate, which only requires 0.57 lbs. of acrylic acid.
Ethyl acrylate hazards include skin sensitization, eye irritation, inhalation, flammability, and the potential for uncontrolled and rapid polymerization. EA is classified as very flammable with a fire hazard ration of 3. However, the chemical industry has handled EA safely for more than 80 years, and when properly inhibited, EA is stable under the recommended storage conditions.
The following principles must drive the handling and polymerization of EA: