1,4-Dioxane Chemistry, Uses, and Occurrence - Environmental Investigation and Remediation - page 88

1,4-dioxane. One formulation of wood glue contained from 1% to 5% 1,4-dioxane (DAP, Inc.,
1994). Some formulations of contact cements had ratios of 1,4-dioxane to methyl chloroform at
considerably higher proportions than those found in degreasing compositions of stabilized methyl
chloroform (Wilke et al., 2004). DAP's Smooth Spread Contact Cement had 2.5% 1,4-dioxane and
only 15-20% methyl chloroform (DAP, Inc., 1990).
Adhesives used in architectural coatings are thought to be the primary cause of 1,4-dioxane detec-
tions in indoor air samples (Hodgson and Levin, 2006). In ofi ces equipped with cubicles, adhesives
are used to join the many components of cubicle furniture; coatings and varnishes may also contain
compounds bearing 1,4-dioxane. Testing of indoor air in ofi ces using cubicles detected 1,4-dioxane
as well as naphthalene, benzene, trichloroethylene, and perchloroethylene. Newer ofi ce furniture is
designed to avoid emissions of these compounds (Betts, 2005). Draperies and drapery linings also
emit measurable concentrations of 1,4-dioxane to indoor air (Smith and Bristow, 1994).
Film cements for joining or mounting sections of cellulose triacetate movie i lm use acetone,
methylene chloride, and 1,4-dioxane as solvents. 1,4-Dioxane was a signii cant component in com-
mercial i lm cement, exceeding 10% in some formulations (Thompson-Hayward Chemical Company,
1993). Another variety of i lm cement is composed of 50% 1,4-dioxane (Eastman Kodak Company,
1998). 1,4-Dioxane is used to dissolve resins and polymers into solution for i lm coating. It is also
used as a photochemical reaction/synthesis medium as well as for miscellaneous photographic
research and development projects (USEPA, 1996c).
2.3.9 P OLYURETHANE M ATERIALS FOR M EDICAL D EVICES
Polyurethanes are durable elastomers used for a wide variety of applications, including l exible and
rigid foams, adhesives, seals, gaskets, carpet padding, and hard plastic parts. Polyurethanes are
biocompatible, which makes them suitable for medical devices. Medical devices made with poly-
urethanes include pacemaker leads, catheters, feeding tubes, angioplasty balloons, condoms, surgical
gloves, wound dressings, and many other products. Medical devices are made by injection molding,
extrusion molding, and solution processing. Mold-release solvents include 1,4-dioxane, tetrahydro-
furan, dichloromethane, methyl ethyl ketone, N , N -dimethylformamide, N -methylpyrrolidone, cyclo-
hexanone, and chloroform. These solvents contribute to highly transparent polyurethanes, a desired
feature for medical devices. 1,4-Dioxane and other polyurethane solvents dissolve polymers and form
clear solutions. Criteria for solvent selection include ease of solvent removal from the product; all
traces of solvents must be eliminated because even trace amounts may interfere with the treatment
and the patient's health (Wypych, 2001).
2.3.10 S OLVENT -B ASED C LEANING A GENTS
Where methyl chloroform was a constituent of various household and automotive consumer and
commercial contact cleaning agents, 1,4-dioxane was often present in the low percentage range as a
stabilizer. Some cleaning agents are better known for their main ingredient, which may mask the
presence of methyl chloroform and 1,4-dioxane. For example, brake-cleaning formulations used in
automotive shops use tetrachloroethylene as the primary solvent (60-65%), but also contain methyl
chloroform (30-35%) and 1,4-dioxane (2.5%) (Valvoline Oil Company, 1991). Some aerosol-spray
brake-cleaner compositions were primarily methyl chloroform (89%), with higher percentages of
1,4-dioxane than normally required for vapor degreasing (up to 6.8%) (CRC Chemicals, 1987).
Other solvent-based consumer products contained only small amounts of methyl chloroform but larger
amounts of 1,4-dioxane. Some consumer rust-removing agents contained up to 10% 1,4-dioxane, but
only 4% methyl chloroform, with butyl alcohol and butyl cellosolve as the primary ingredients (Watsco
Components, Inc., 1991). Rust inhibitors have been formulated with as much as 50% methyl chloroform
and 0.8% 1,4-dioxane (Crown Industrial Products Company, 1989). Commonly used solvents for loosen-
ing frozen hardware such as nuts and bolts contained 1-3% 1,4-dioxane (Loctite Corporation, 1995).