May '14

For the Business of Apparel Decorating

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en frame. The inks available offered little from the standpoint of being us- er-friendly. They were ready-to-use from the bucket and few, if any, modifiers were available. Ink drying in the screen was a simple way of life and it was the re- sponsibility of an agile press operator to ensure that the screens remained wet, and the stencils, opened. A spray bottle with a diluted solution of Ethylene Glycol was often kept at the press to mist the screens whenever a stoppage would occur. As issues arose, modifiers were introduced to address the respective issues within the ink line. One of the first was an anti-crocking agent. This helped the early water-based ink films that had a tendency to dry and crock from any surface abrasion. Today, water-based inks offer numerous modifiers to assist in ink film elon- gation, wash fastness, and softening of the hand of the print. However, a majority of the textile screen-printing industry is entrenched with plastisols, which poses a serious challenge for those converting to a water-based printing system. Water-Based Printing tiPs Curing • First and foremost, you must have the ability to properly cure the ink. The best dryers for this application are gas fired/ forced air dryers. It is the hot forced air that is needed to properly drive the wa- ter from the ink film and cure the ink. • Always wash-test prior to delivery to ensure the ink film is properly cured. StenCil • Make sure that you are employing a water-resistant screen emulsion. Wa- ter-based products can wreak havoc on the screen stencil and, thus, require a water-resistant emulsion. • The water-based inks offered today can print through mesh counts as low as 80 for opacity printing to as high as a 305 for halftone and fine line detail printing. Always refer to the manufacturer's rec- ommendations for mesh counts based on application. Printing • As opposed to printing with plastisols, where we strive to minimize the ink film, you will want to drive the ink into the fab- ric when printing water-based inks. The saturation of the fabric will help ensure a good washfastness and color intensity once the ink film is properly cured. • To this end, you will want to employ a shorter squeegee that will not only con- form to the surface of the mesh, but will also increase the penetration of the ink into the fabric. • The use of higher tension screens will also minimize the need for excessive squeegee pressure. Just as with plasti- sols, excessive squeegee pressure can result in loss of definition. Shown is an all-over water-based graphic printed on retensionable frames. 20 1 4 M Ay Printwear | 83 PW_MAY14.indd 83 4/17/14 4:53 PM

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