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Acrylic acid
Description: Acrylic acid (C.A.S. 79-10-7) is a colorless liquid or solid that is used in the manufacturing of plastics, bondings, and hydrogels used for contact lenses. It is used as a chemical intermediate for ethyl acrylate, n-butyl acrylate, methyl acrylate, and 2-ethylhexyl acrylate. It is used in the production of floor polish formulations, molding powder for signs, construction units, decorative emblems and insignias, polymer solutions for coating applications, emulsion polymers, paint formulations, leather finishings, and paper coatings. It is used as a copolymer component in aerosol hair sprays, and in shampoos as a foam stabilizer. In medicine and dentistry, it is used for dental plates, artificial teeth, and orthopedic cement. Acrylic acid monomer is used in latex applications to increase stability in order to prevent premature coagulation. Chemical properties: Acrylic acid and its fumes have an acrid and unpleasant odor. It is corrosive to metals, and is a strong irritant. It is miscible with water, alcohol, chloroform, and ether. It polymerizes readily in the presence of oxygen. It is soluble in benzene. It boils at 141 degrees C, and melts at 12.3 degrees C. Synonyms for acrylic acid are acroleic acid, ethylenecarboxylic acid, propene acid, propenoic acid, 2-propenoic acid, and vinylformic acid. Identification: Health effects: Acrylic acid is a severe skin and eye irritant. It may also be a sensory irritant. Exposure can occur through inhalation, ingestion, and skin and eye contact. Exposure Values: Economics: U.S. manufacturers of acrylic acid are BASF Corporation, Freeport, TX; Union Carbide Corp., Taft, LA; Rohm and Haas, Deer Park, TX; and Celanese LTD., Clear Lake, TX, and Pampa, TX. Regulation: Acrylic acid is regulated under the Emergency Planning and Community Right-to-Know Act (EPCRA); Clean Air Act, as a Hazardous Air Pollutant; Comprehensive Environmental Response, Compensation, and Liability Act; and Clean Water Act, as a Priority Pollutant. Under EPCRA, releases of more than one pound of acrylic acid into the air, water, and land must be reported annually and entered into the Toxics Release Inventory (TRI). National Overview of 1998 Toxics Release Inventory See EPA's Toxic Release Inventory. Notations: The NIOSH recommended exposure limits (RELs) are time-weighted average (TWA) concentrations for up to a 10-hour workday during a 40-hour workweek. A short-term exposure limit (STEL) is designated by "ST" preceding the value; unless noted otherwise, the STEL is a 15-minute TWA exposure that should not be exceeded at any time during a workday. A ceiling REL is designated by "C" preceding the value. Any substance that NIOSH considers to be a potential occupational carcinogen is designated by the notation "Ca." The OSHA permissible exposure limits (PEL) are found in Tables Z-1, Z-2, and Z-3 of the OSHA General Industry Air Contaminants Standard (29 CFR 1910.1000). Unless noted otherwise, PEL are TWA concentrations that must not be exceeded during any 8-hour workshift of a 40-hour workweek. A STEL is designated by "ST" preceding the value and is measured over a 15-minute period unless noted otherwise. OSHA ceiling concentrations (designated by "C" preceding the value) must not be exceeded during any part of the workday; if instantaneous monitoring is not feasible, the ceiling must be assessed as a 15-minute TWA exposure. In addition, there are a number of substances from Table Z-2 (e.g., beryllium, ethylene dibromide, etc.) that have PEL ceiling values that must not be exceeded except for specified excursions. For example, a "5-minute maximum peak in any 2 hours" means that a 5-minute exposure above the ceiling value, but never above the maximum peak, is allowed in any 2 hours during an 8-hour workday. Information Sources:
Originally published in Environment Writer by the National Safety Council. Reprinted with permission. Environment Writer Metcalf Institute for Marine and Environmental Reporting University of Rhode Island Graduate School of Oceanography Office of Marine Programs Narragansett, RI 02882 Tel: 401-874-6211; Fax: 401-874-6485 Disclaimer * Copyright 2002-2006 * All rights reserved. * University of Rhode Island |