N-methylpyrrolidone (NMP) is an organic solvent. It is a volatile organic compound (VOC) and has a low vapor pressure of 0.29 mm Hg at 68°F (0.39 mbar at 20°C). It is combustible, with a flash point of 199°F (93°C). A threshold limit value (TLV) has not been established by ACGIH.
NMP cleans heavy oil and carbon deposits from engine parts. It is an excellent solvent for many coatings, including polyurethanes, printing inks, epoxy resins, polyamidimide-based wire enamels, and water-based coatings.
Many plastics, including polystyrene, polyesters, and polyvinyl chloride are soluble in NMP. NMP is also effective for stripping many types of paints.
NMP is acceptable for use in both immersion and ultrasonic processes. Pure NMP is commonly used, but is also available blended with surfactants or other solvents. It can be combined with a water rinse in semiaqueous processes.
Many oils become soluble in NMP only when the solvent is above 145°F (63°C). The oils can be separated from the solvent after the cleaning step by lowering the NMP temperature. The solvent can then be reused and the oil can be recycled.
NMP is listed under SARA 313 Title III (EPCRA), section 313(d)(2)(B), serious or irreversible chronic health effects. The effective date was January 1, 1995. The full discussion can be found in the Federal Register dated November 30, 1994, Vol. 59, No. 229, pp. 61432-61485
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02 May 2001