Printing Tips for Today’s Fabrics Part 3

In an article that was recently featured in Screen Printing Magazine’s October/November 2016 issue, and on Screenweb.com, Kieth Stevens gives us some tips on printing on today's modern fabrics. Here is Part 3 of the article. Popular, profitable, and often a pain in the neck to print, the latest fashion fabrics can present quite a challenge to shops accustomed to printing standard plastisols on all-cotton garments. Garment Considerations Typical plastisol inks cure between 315 and 330 degrees Fahrenheit, which isn’t a problem when printing on cotton substrates. With synthetic performance fabrics, however, such temperatures might be an issue. Beyond dye migration, the garments may even shrink or become deformed. A low-cure additive will allow you to reduce the curing temperature to around 280 degrees Fahrenheit to give you some breathing room. Always test a garment before a full production run, first to make sure an unfamiliar fabric can withstand the curing temperature, but also to ascertain that the ink is fully cured. A wash test is an ideal indicator of how well the ink is cured. Under-cured ink will wash off – if not entirely, then surely in several spots, most likely in the center of a design. In addition, the ink shouldn’t crack when the fabric is stretched. This could be a sign of under-curing, though with the newer low-cure inks for performance fabrics, it could be a sign that the curing temperature was too high. Another type of print flaw might not be apparent to consumers until they try the garment on. Many of the newer fabrics being used today, especially for athletic wear, can’t hold up the weight of a standard print like the old cotton standbys. Some garments are so light that even a small print can make the decoration hang or drape stiffly. For these garments, use finer meshes with higher quality inks to reduce the weight of the ink deposit. This makes the design not only look better, but also feel more comfortable when worn. Heavier garments, on the other hand, may be more prone to a defect known as fibrillation, in which yarn fibers from below the ink surface come through the ink film after washing, making the print appear fuzzy. Certain types of yarn, notably 100-percent cotton but also 100-percent acrylic and acrylic/cotton blends, are more prone to fibrillation than others. The best way to control it is to make sure the ink is fully cured and consider using a slightly coarser mesh count to deposit more ink. Using a matte-down screen after flashing the underbase will also help keep the fibers down and the surface of the print smooth. Work uniforms present different considerations. More companies today have their logos or slogans screen-printed onto their uniforms rather than embroidered – a nice source of new business for some shops. However, uniforms must withstand an industrial washing process that is far more aggressive than what a standard consumer garment requires. Using a nylon-style catalyst when printing uniforms can dramatically improve the durability of the ink deposit, enabling it to withstand many industrial washes. Garments with irregular or bumpy surfaces, such as zippers and hoodies, pose unique challenges when these features must be printed over. Often, printers have to improvise a solution in order to get the job done, and it may mean creating a custom platen that conforms to the irregular surface. I once made a platen out of quarter-inch aluminum to fit bobby socks so I could print designs like poodles and dice on the cuffs. Some strategically placed cardboard may also help minimize the bump caused by zippers and buttons. Finally, fabrics designed to hold up in outdoor conditions can be problematic. Typically, printers use catalysts to help bond the ink to nylon fabrics, but many don’t know that catalysts can also help with especially difficult substrates such as certain polyester outerwear materials and the synthetics used for backpacks. Test it when you’re dealing with a problem fabric to see if it works. Another tip when you’re working with water-repellent fabrics: Try dabbing a little rubbing alcohol over the area to be printed. This may remove some of the water-repellent coating so that the ink with the catalyst can better adhere to the garment. Test, Test, Test Here is my motto for delivering the best possible outcome for your customer: Thoroughly test all prints and shirts before committing to costs and production methods. Never relax and assume that everything will run like the last time, even for a repeat job. A printer once told me that their customer supplied them with the same nylon jackets as a previous order, yet this time the jackets bled through the white print. What the customer did not tell them was that they had switched manufacturers, so instead of printing nylon again, the shop was dealing with a dyed polyester fabric. That turned out to be a costly mistake, as the bleeding was not discovered until several days after they had completed the job. Everyone is looking out for themselves and you should be no different. A good customer will understand and appreciate your caution. They may even refer you to others because your service stands out. Read Part I, Part II

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