The acrylate esters are used in the manufacture of leather finish resins and textile, plastic and paper coatings. Methyl acrylate, producing the hardest resin of the acrylate ester series, is used in the manufacture of acrylic fibres as a co-monomer of acrylonitrile because its presence facilitates the spinning of fibres. It is used in dentistry, medicine and pharmaceuticals, and for the polymerization of radioactive waste. Methyl acrylate is also utilized in the purification of industrial effluents and in the timed release and disintegration of pesticides. Ethyl acrylate is a component of emulsion and solution polymers for surface-coating textiles, paper and leather. It is also used in synthetic flavouring and fragrances; as a pulp additive in floor polishes and sealants; in shoe polishes; and in the production of acrylic fibres, adhesives and binders.
More than 50% of the methyl methacrylate produced is utilized for the production of acrylic polymers. In the form of polymethylmethacrylate and other resins, it is used mainly as plastic sheets, moulding and extrusion powders, surface coating resins, emulsion polymers, fibres, inks and films. Methyl methacrylate is also useful in the production of the products known as Plexiglas or Lucite. They are used in plastic dentures, hard contact lenses and cement. n-Butyl methacrylate is a monomer for resins, solvent coatings, adhesives and oil additives, and it is used in emulsions for textiles, leather and paper finishing, and in the manufacture of contact lenses.
As with many monomers—that is, chemicals which are polymerized to form plastics and resins—the reactivity of acrylates can pose occupational health and safety hazards if sufficient levels of exposure exist. Methyl acrylate is highly irritating and can cause sensitization. There is some evidence that chronic exposure may damage liver and kidney tissue. Evidence of carcinogencity is inconclusive (Group 3—Unclassifiable, according to the International Agency for Research on Cancer (IARC)). By contrast, ethyl acrylate is rated as a Group 2B carcinogen (possible human carcinogen). Its vapours are highly irritating to the nose, eyes and respiratory tract. It can cause corneal lesions, and inspiration of high concentrations of the vapours can lead to pulmonary oedema. Some skin sensitization following contact with liquid ethyl acrylate has been reported.
Butyl acrylate shares similar biological properties with methyl and ethyl acrylate, but the toxicity appears to decrease with an increase in molecular weight. It too is an irritating substance capable of causing sensitization after skin contact with the liquid.
The methacrylates resemble the acrylates, but are less biologically active. There is some evidence that the substance does not cause cancer in animals. Methyl methacrylate can act as a central nervous system depressant, and there are reports of sensitization among workers exposed to the monomer. Ethyl methacrylate shares properties of methyl methacrylate but is much less irritating. As with the acrylates, the methacrylates decrease in biological potency with increasing molecular weight, and butyl methacrylate, while an irritant, is less irritating than ethyl methacrylate.
Table 1 - Chemical information.
Table 2 - Health hazards.
Table 3 - Physical and chemical hazards.
Table 4 - Physical and chemical properties.