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Preventing and Removing Haze

(December 2013) posted on Wed Dec 18, 2013

The products and processes that can streamline your screen-reclaiming efforts.


By Screen Printing's Solution Sourcebook

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Ghost haze is a problem you can conquer when you arm yourself with the proper tools and techniques. However, at times it seems as if there’s no clear delineation between degreasers, abraders, ink removers, and haze removers. Some degreasers also dehaze, and some dehazers also degrease. There are abraders that dehaze and dehazers that abrade. And now some ink removers allegedly degrease and dehaze. It’s enough to make your head spin. This article will try to clear up the confusion. Let’s simplify matters by organizing and defining these products.

Degreasers consist of one or more of the following ingredients: detergents, emulsifiers, and surfactants and other wetting agents. They clean the mesh prior to application of emulsion or film and remove most forms of contamination and foreign matter from the screens so a smooth, uniform, blemish-free coating can be achieved. Screens should be degreased just before the mesh is coated. Degreasers are not intended to dehaze.

Abraders microscopically scratch the knuckles of the mesh, which increases the surface area and helps improve stencil adhesion. The active ingredient is silicon carbide, which is a dark, insoluble crystalline compound used as an abrasive. These products are most frequently used to improve the durability of capillary and indirect films when longer production runs are required. Abraders are not intended to dehaze.

Ink removers consist of various blends of solvents used to dissolve inks for cleanup after printing, or for use while printing. If used after printing, they are classified as ink washes or ink degradants. These ink removers evaporate slowly, contain emulsifiers, and are used during the reclaiming process. Ink removers used while printing are classified as screen openers, press washes, or on-press cleaners. These ink removers are used to open up a clogged screen, to clean excess ink from the substrate side of the screen, and for making color changes at press. They usually evaporate faster than ink washes and preferably leave little to no oily residue so tapes can be used promptly thereafter. Ink removers are not intended to dehaze, but some show promise when used only for removing ink haze.


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