There’s never been a better time to hop aboard the water-based inks train.
By Lon Winters
A Wide Range of Options
One commonly used water-based ink system is known as discharge. These inks chemically remove the color from the garment, replacing the dye being withdrawn with the colorant in the ink while retaining a soft feel. Discharge inks have been traditionally used in conjunction with plastisol and reduce the need for an underbase when printing on dark, natural-fiber garments. Most common formulations require the addition of zinc formaldehyde sulfoxylate as an activator, though formaldehyde-free formulas are available. These inks are reasonably easy to handle, assuming you have a water-resistant stencil that has been fully cross-linked and dried. According to Jesse Martinez, sales manager for Matsui International, the color values of discharge tend to give a somewhat unstable, vintage look, noting that they also have weak washfastness.
Newer, more sophisticated water-based ink systems are now available from various manufacturers on a large scale. For years, these were referred to as rubber inks in Asia, though the correct name is HSA (high solids acrylic). HSA inks are known for having similar performance characteristics as plastisol. Though they are water-based, they are opaque and vibrant. They can be used on both dark and light fabrics. They provide a soft feel and desirable drape. They are also suitable for use on polyester and poly/cotton blends, in addition to 100-percent cotton. HSA inks are flexible enough to be used on stretch materials containing blends of Lycra or spandex that are increasingly popular in performance apparel. They also have excellent fiber-matting properties and washfastness. Based on these characteristics, HSA inks are now often specified for use by marketers, contract printers of licensed goods, and many brands themselves.
Still, HSA technology isn’t the same as plastisol. For years, we have come up with creative ways to massage the separations and screens in order to do some wet-on-wet printing using HSA inks, with limited success. Recent innovations have led to the development of hybrid HSA/polyurethane blends, beginning with Virus and its WOW product line and now emulated by other companies taking a similar approach. We’ve been able to get up to eight colors to print wet on wet with these inks. According to Beppe Quaglia of Virus, the WOW project is much broader than simply enabling wet-on-wet printing, encompassing other considerations such as sustainability, ecology, costs, and reduction of consumables.
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