* What are they made of and when do they work? Three common formulations of washes and the ways to make them work are listed below. Every day, printers are discovering new ways to make low-volatility washes work by trial and error. For instance, cleaning is easier if blankets are washed immediately after shutting down a press so that the blanket dries while you change-over the plates or make adjustments.

Petroleum Distillates. The "traditional," fast-drying washes simply consist of low-boiling crude oil distillates and resemble a mix of paint thinner and gasoline. For more aggressive roller washes, chlorinated petroleum products ^a are added to formulations. Safer, less volatile petroleum distillates can be used in virtually the same way as the "old" formulations. Limonene, a citrus oil, is a substitute wash ingredient that poses lower health risks than aromatic naphthas ^a. (See Note ^a, p. 4.)

Petroleum Distillates with Detergents. The detergents allow the wash to mix with water by forming emulsions-- tiny drops of oil, coated with detergent, and suspended in water. Formulations with detergents work best when followed by a water rinse.

For manual blanket washing-- Three steps may be required: (1) Wipe the blanket with the wash. (If you encounter problems getting rags to absorb the wash, soak rags in a container of the wash or cut the wash with water); (2) Wipe the blanket with a second rag that is damp with water; and (3) If needed, dry with a third clean rag.

For automatic blanket washing-- Washes with detergents work best if your equipment has a separate water reservoir that can provide a final water rinse via either the cloth or brush cleaning mechanism. The water delivery rate must be slow to prevent web breaks.

For roller washing-- Apply the wash to rollers and allow it to spread through the roller train. Then, squirt on water to rinse off the ink & wash emulsion and engage the wash-up blade.

Vegetable Esters with Detergents^a. Vegetable ester washes can be used in a similar way as the petroleum distillates with detergents. They can be just as effective, and they pose lower health risks. These washes work by mixing with the ink and, when water is applied, emulsifying the ink so it can be wiped off. If a wash is too viscous (thick and sticky), try cutting the wash with water.

*What makes for a safe wash?

==> Look for washes with lower vapor pressures^b and lower VOC contents^b. (See Note ^b, p. 4.)

==> Look for washes that contain less harmful chemicals. The figure below ranks the health risks of typical blanket wash ingredients.

Washes containing only vegetable esters ^a and detergents ^a pose the lowest risks to safety, health, and the environment compared to all other wash formulations. They have negligible vapor pressures and will not evaporate at room temperatures; this prevents both breathing exposure and air emissions. They cause the least damage to the skin and gloves. They are readily biodegradable when discharged in wastewater from rag launderers. They are potentially harmful only if mists form during spraying or brushing.

If a vegetable ester wash cannot be used, look for washes that contain mainly paraffins ^a (for example, "Hydrotreated petroleum" or "hydrotreated naphtha"). Hydrotreating is a process that converts potentially harmful naphtha ^a into paraffins. Toxicity decreases with increasing number of carbon atoms for paraffins with seven or more carbon atoms, so look for greater than C8 ^a paraffins to avoid health risks, such as headaches or brain damage. Paraffins alone do not cut ink well, so blanket washes containing mostly hydrotreated petroleum usually also contain some terpenes ^a or naphtha.

Also look for higher boiling washes, namely washes that start boiling above 300 ^oF. Higher boiling washes cause less breathing exposure and lower air emissions even if they will still completely evaporate if left in the open (100% VOC Content ^b).

Avoid naphthas, paraffins, and mineral spirits that boil between 100 ^oF and 300 ^oF because chemicals in this boiling range can cause cancer and brain damage. Also avoid methylene chloride, and the potentially harmful detergents listed on Page 4.

Vendors of Lower Risk Washes
AM Multigraphics, Mt Prospect, IL, 847-375-1700
Anchor/Lithkemko, Orange Park, FL, 800-354-2300, 904-264-3500
Chemical Marketing Co., Minneapolis, MN, 612-785-0055
Inland Technology, Tacoma, WA, 800-552-3100.
KB Litho Supply, Kansas City, MO, 800-821-2240, 816-241-3070
Printex Products Co, Rochester, NY, 800-236-8381, 716-336-2215.
Prisco Printers Service, Newark, NJ, 800-654-1357, 201-589-7800.
RBP Chemical Corp., Milwaukee, WI, 414-258-0911.
Siebert, Inc., Lyons, IL, 708-442-2010.
Tower Products, Palmer, PA, 800-527-8626.
Varn Products, Addison, IL, 800-336-8276.

What's on the market?
(Other similar products, which we have not received information on, are also available.)

Vendor/Product	Vapor Pressureb (mm Hg at 68 oF)	VOC Content b (lb/gal)	Flash Point b (oF)	Chemical Make-up and Other Notes
AM Multigraphics: Pressions	2.3	1.0	82	Petroleum distillate (Paraffin and naphtha a) and detergents.
Anchor/Lithkemko: Envirowash series	<1, <1, <1	0.3 , 2.2, 3.5	>200, 145, 164	Several lines: vegetable ester and detergents; naphtha and paraffin blends, and mixes of both. Typically contains C9-C16 a naphthas and C6-C16 paraffins.
Chemical Marketing Co.: Press Wash 2000	< 1	7.0	150	Paraffins (C9 to C16), Naphthas (C9-C16), and detergents (APE a).
Inland Technology: Press-Tige	<10 (77 oF)	6.42 (100%)	112	Paraffins (C10-C11) and d-limonene. Does not mix with water.
KB Litho Supply: Tonic-FR	<1	0.026	>212	Vegetable ester and detergents. Reference available for use with an automatic blanket washer.
Printex: Tex Evergreen, CPD-2, Tex Lo VOC-50	<0.1, <0.1, <0.1	0, 2.4, 3.5	none, 150,170	Vegetable ester and detergents. Paraffins (C9 to C16), Naphthas (C9-C16), and detergents.
Prisco: PES series	<1 to 2.7	0.9 to 5.4	>200 to 105	Paraffin (C9-C12), naphtha (C8-C16), vegetable ester, and detergents (PGE or ABS a)-- several blends.
Siebert: BL-7, Magic522	< 1 (<0.1)	<0.16	>300	Vegetable ester and detergents.
RBP Chemical: LV 3600	Not Reported	3.6	108	Paraffin (C6-C20), naphtha (C8-C10), and detergents. Some products contain ethylene glycol ethers.
Tower Products: LO-VO series	<1, 1, 1, 2.8	0, 1.6, 2.1, up to 6.9 (100%)	200, 150, 150, 102	Vegetable ester and detergents; naphtha (C8-C16), paraffin (C9-C12), and detergents (PGEa). Automatic blanket wash vendor approved.
Varn Products: V-120	2.60	6.78 (100%)	106	Paraffin (C9-C12), Naphtha (C8-C10), and detergents (PGE).

Notes About Terms Used Above and On MSDSs (Material Safety Data Sheets)

^a Common wash ingredients and terms used to describe ingredients are explained below.

Carbon number refers to the number of carbon atoms in a chemical molecule. Thus, "C8," or "8 carbon," is a molecule with eight carbon atoms. The more carbon atoms, the higher the boiling point of typical blanket wash ingredients.

Chlorinated compounds found in roller washes, such as methylene chloride, pose the highest health risks of all common wash ingredients. These ingredients usually contain the letters "chlor" or "chloro."

Detergents in washes are often glycol ethers. Ethylene glycol and ethylene glycol ethers are Hazardous Air Pollutants (HAPs) under the Clean Air Act. Propylene glycol and propylene glycol ethers (PGE) are not HAPs; typical propylene glycol ethers are two to ten times less toxic in air than typical ethylene glycol ethers found in washes. Some detergents pass through municipal treatment plants and can harm fish in rivers; some studies have raised concerns about alkylphenol ethoxylates (APE) and alkylbenzene sulfonates (ABS). Ask vendors for formulations with other detergents, such as "straight chain" n-alkyl ethoxylates, n-alkyl sulfonates, or propylene glycol ethers (PGE).

Naphtha refers to aromatic chemicals distilled from crude oil.

Paraffin refers to aliphatic or saturated petroleum distillates.

Terpenes are oils extracted from citrus peels or pine bark, such as d-limonene. Terpenes can be skin irritants and impurities can cause allergies and other health effects in some people.

Vegetable esters are vegetable oil that has been treated so that it cuts ink better. This ingredient is also called fatty acid ester or emery oil. Unlike naphtha and paraffins, vegetable esters are weak emulsifiers.

^b Properties of washes. These can be used to judge the risks a blanket or roller wash poses to safety, health, and the environment.

VOC content, measured by EPA Method 24, is the total weight of material that leads to ground-level ozone formation (smog) and that evaporates under rigorous test conditions. Method 24 subjects a 1-2 mm thick film of the blanket wash to 110 ^oC for 1 hour in an oven. Typical units are pounds per gallon (lb/gal). The lower the VOC content the better.

Vapor pressure provides an indication of how quickly VOCs will evaporate. Low vapor pressure solvents evaporate more slowly than high vapor pressure solvents. For reference, paint thinner (xylene and/or toluene) typically has a vapor pressure between 8 mm Hg and 26 mm Hg at room temperature. Vapor pressure increases with temperature. Typical units are millimeters of mercury (mm Hg). The lower the vapor pressure the better.

The flashpoint is the temperature at which a spark above the liquid would ignite a flame. The higher the flash point the safer the wash.

For more information contact the Small Business Technical Assistance Program, Lincoln-Lancaster County Health Department, 441-6235.