Environmental Engineering Reference
In-Depth Information
TABLE 1.5
Estimated U.S. End-Use Pattern for Methyl Chloroform
Vapor Degreasing
(%)
Cold Cleaning
(%)
Aerosols
(%)
Adhesives
(%)
Coatings and Inks
(%)
Electronics
(%)
Year
1980
70
5
—
—
3
1984
22
40
10
12
1
6
1985
22
41
7
10
2
6
1989
34
12
10
8
5
4
1991
50
11
11
8
4
1995
25
—
5
3
5
Sources:
U.S. Environmental Protection Agency (USEPA), 1994a, Locating and estimating air emissions from methyl chlo-
roform. U.S. Environmental Protection Agency, Ofi ce of Air Quality Planning and Standards. EPA/454/R-93/045
and Kavaler, A.R. (Ed.), 1995,
Chemical Marketing Reporter
247 (February 27): 9, 37.
variety of paint coatings. Dichloromethane is found in industrial and commercial furniture strippers
and in home paint removers, and it is used extensively in both l ow-over and dip tanks in furniture-
rei nishing operations. It is also used in aircraft-maintenance formulations to inspect surfaces for
damage (ATSDR, 2000).
Dichloromethane is also used extensively as a foam-blowing agent for the production of softer
grades of l exible polyurethane foams for furniture and bedding industries. Evaporation of the
solvent during production causes expansion of the cells in urethane polymer foam, which reduces
the urethane density while maintaining its l exibility. Dichloromethane controls the temperature of
the reaction, which may otherwise become sufi ciently high to burn or scorch the foam interior
(HSIA, 2003).
Dichloromethane use as a propellant in aerosols such as insecticides, hair sprays, and spray
paints increased signii cantly after the regulation of chlorol uorocarbons. Dichloromethane was a
replacement for l uorocarbons in aerosols (World Health Organization, 1984b). Dichloromethane is
used in aerosols as a strong solvent, a l ammability suppressant, a vapor-pressure depressant, and a
viscosity thinner. However, labeling requirements and health and environmental concerns led to a
decline in the use of dichloromethane in consumer aerosol products in the late 1980s. Dichloromethane
was used in hair sprays before it was banned by the Food and Drug Administration in 1989. It con-
tinues to be used in specialized spray paints and lubricants (ATSDR, 2000).
Table 1.6
provides the approximate breakdown of the major uses of dichloromethane from the
1970s through the 1990s; usage i gures vary widely by information source and year.
Dichloromethane is used as a reaction and recrystallization solvent in the extraction of several
pharmaceutical compounds and in the production of many antibiotics and vitamins. It has been used
as a carrier to coat tablets. Dichloromethane is eliminated from the coating of the i nished tablet in
order to comply with Food and Drug Administration regulatory standards.
A wide variety of nonpharmaceutical applications have been found for dichloromethane (World
Health Organization, 1984b; USEPA, 1994c; ATSDR, 2000; European Chemicals Bureau, 2000d;
HSIA, 2003; National Library of Medicine, 2006). It has been used in cold and vapor degreasing of
metals. It is involved in the manufacture of synthetic i bers and polycarbonate resin used for the
production of thermoplastics. Dichloromethane is a component in i re-extinguishing products and
serves as a coolant and refrigerant. It is used as a solvent in the production of cellulose triacetate as
a base for photographic i lm, in the solvent welding of plastic parts, as a metal-i nishing solvent,
and as an extraction solvent for naturally occurring, heat-sensitive products including edible fats,
cocoa butter, caffeine, and beer l avoring in hops. Dichloromethane serves as a releasing agent to
prevent the manufactured part from permanently bonding to the mold and for cleaning electronic
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