Cleaning and Degreasing Operations
To assure proper adhesion, metal surfaces must be cleaned and degreased prior to the application of coatings. The most common surface contaminants are grease, oils, waxes, and soils. Traditionally, petroleum-derived chemicals such as glycol ethers, TCE, and methylene chloride have been used for solvent cleaning operations. These solvents can be used in cold cleaning, the most common type of cleaning, which involves either wiping the metal surfaces or immersing the part in a solvent tank. Another method is vapor degreasing, in which a tank of solvent is heated to its boiling point, releasing a vapor that condenses on the cooler metal part and dissolves the oil-based contaminants on the surface. Both of these methods clean metal surfaces very well; however, the petrochemical solvents release VOCs into the atmosphere and are regulated by the EPA as hazardous air pollutants (HAPs) and ozone precursors. Fortunately, there are alternatives.

Biochemical Cleaning/Degreasing Solvents
Companies across the country are developing and marketing cost-effective biochemical solvents for use in the metal and plating industry. These plant-based alternatives can perform the same functions as toxic petrochemicals, but are safer to use and are less harmful to the environment. (See FactSheet 23 of the Pollution Solutions series for information on other bio-based degreasers used primarily on metal surfaces in the automotive industry.)

Petroferm Inc. (Fernandina Beach, FL) manufactures cleaning solvents based on a blend of highly refined orange terpenes, alcohol, and aliphatic hydrocarbons. BIOACT 105® removes a wide variety of soils, including grease and oils, in immersion and hand-wipe cleaning applications. It evaporates from metal surfaces quickly, leaving no residue, and without creating an offensive odor. BIOACT 105® is also compatible with a variety of cleaning systems, including ultrasonics, spray systems, recirculating parts washers, and immersion/soak tanks. BIOACT 105® sells for approximately $1.25/lb. Petrochemical-based solvents tend to be less costly, ranging from $0.60/lb for TCE to $1.07/lb for glycol ethers.1 None of the components in BIOACT 105® are listed on the EPA's Toxic Release Inventory (TRI) or as HAPs. Because BIOACT 105® cleans more efficiently than petroleum-based solvents, less solvent is required for the same application, making the cost difference nominal. In addition, using less solvent reduces the waste stream, thereby reducing disposal costs.2

Terpene Technologies Ltd. (Rochester, NY & Burlington, ON) manufactures a variety of cleaning solvents that are based on terpenes derived from conifers. These natural pine terpenes, called pinene, are obtained as a by-product of the pulp and paper industry. Tarksolª products are designed for industrial degreasing and coating removal applications for the metal finishing industry. They are effective for parts washing and wiping of metal parts, equipment, tools, engine blocks, and concrete floors. Tarksolª products are compatible and used in a variety of cleaning systems including ultrasonics, hot and cold dip and soak tanks, spray systems, and wipe methods. Tarksolª solvents do not contain any aromatic, petroleum, chlorinated, or fluorinated solvents, and are therefore not regulated under the Clean Air Act as ozone precursors, or HAPs. They also have low toxicity, high biodegradability, and a faint pine odor. Tarksolª products are effective at dilutions of typically 10% by volume, offering greater cleaning efficiency as compared to petroleum-based solvents used undiluted, such as MEK and TCE. Tarksolª solvents sell for $1.00-4.00/lb depending on the formulation, compared to TCE at $1.07/lb. The higher initial purchase cost is offset by several factors. Tarksolª solvents can be used in smaller quantities than petrochemical solvents, cleaning a greater surface area with a given quantity of solvent. They do not sustain the same levels of evaporative losses as high volatile petrochemicals do. In addition, the life of Tarksolª solvents can be extended by using oil removal and solution filtration techniques. Thus, the price of the terpene-based products becomes comparable, and some manufacturers have reported reduing their consumption and waste stream by up to 50%.3

Kyzen Corporation (Nashville, TN) has developed a line of cleaning solvents based on a non-linear alcohol derived from natural organic materials or biomass, such as corn cobs and spent rice hulls. Its Metalnoxª product line was designed for metal cleaning applications to remove contaminants including oils, grease, coatings, and adhesives. The variety of products in the Metalnoxª line are designed for specific cleaning functions, such as wipe, immersion, or spray, and also for different metal surfaces including copper, aluminum, and other ferrous metals. These solvents are biodegradable, have low flammability, and are not regulated by the TRI or listed as HAPs. Metalnoxª cleaners sell for approximately $1.06-1.64/lb, slightly higher than, but comparable to, glycol ethers at $1.07/lb.4

1. Chemical pricing quoted in Chemical Marketing Reporter, October 7, 1996
2. Product information provided by Chris Collins of Petroferm Inc.
3. Product information provided by R.B.(Barrie) Smith of Terpene Technologies, Inc.
4. Product information provided by Jeff Beard, Kyzen Corporation.

POLLUTION SOLUTIONS is a series of fact sheets about pollution prevention strategies with biochemical substitutes prepared by the Institute for Local Self-Reliance (ILSR). If you would like more information, contact:

Tel: (612) 379-3815 FAX: (612) 379-3920

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