There are four basic solvent types for washing up the press. In most cases, the same wash can be utilized for both rollers and blankets.
Water-miscible washes – the most popular type in the industry, water-miscible (or mixable) washes can generally be blended with 20%-50% water. Featuring moderate drying speeds, these washes remove ink and water-soluble glazes, such as gum and paper fillers in one wash-up. Water-miscible washes are available in detergent, low-VOC, vegetable oil and non-photo-chemically reactive formulas.
Straight solvent washes – an economical alternative to watermiscible washes. They cannot be mixed with water and are, therefore, used directly from the container. This type of wash features fast drying and good penetration of dried ink.
Two-step washes – applied in a sequence, these washes are used for deep cleaning and color changes. The two-step process has been designed to cut wash up time in half when changing from dark to light colors in the same unit. Step one is a blend of detergents, solvents and water in a heavy-viscosity wash. Step one solvents quickly “bite” into the ink and remain on the rollers, while the detergents penetrate into the roller surface and carry the ink and glaze residue down to the wash-up blade for removal. The drying time for step one solvents is slow. Step two is a water-miscible rinse wash that is used to completely remove all of the step one wash and to prepare the roller surface for the next color.
Environmental washes – were designed to meet increased demands created by recent environmental legislation. They use a broad base of ingredients, most of which are designed to lower VOCs, raise flash points, and reduce environmental and health concerns in the pressroom.