Screen printing (also known as silk screening) is a printing technique that uses stencils and ink to create designs on fabric. Although it requires significantly more set-up time than digital printing or heat transfer, screen printing is the most economical method for producing large quantities. Commonly used on cotton or cotton blend apparel, screen printing can be done on 100% polyester using special inks and additives.
|SCREEN PRINTING PROCESS|
|Screen printing on 100% polyester presents two unique challenges. The first is dye migration – ink discoloration that occurs when exposure to high temperatures causes dye to “migrate” from the garment into the screen print ink. To prevent this problem, use highly opaque ink or print a base layer of a barrier material, and cure at the lowest recommended temperature. The second challenge is shrinkage. To avoid this, careful handling is essential when applying heat to polyester fabric, which can shrink or burn at high temperatures.|
FOR SUCCESSFUL SCREEN PRINTING ON 100% POLYESTER, FOLLOW THESE RECOMMENDATIONS:
Work with your ink supplier to select the correct ink for your project – usually a one-step nylon ink or an opaque plastisol ink with a nylon hardener. (The hardener will shorten the life of the ink, however, so prepare only as much ink as you will use in an hour of production.)
When preparing screens, use a high-tension mesh with thin thread. Use consistent off-contact printing (leaving space between the screen and the substrate), which allows a uniform application of ink to the shirt’s surface.
Polyester fabrics tend not to adhere to the pallet as securely as cotton fabrics, therefore be cautious not to shift the garment during printing. Apply ink with a single stroke, which is sufficient to achieve good coverage. In addition, use a direct screen print only if you have a one-color print, or print two colors only if they do not butt up against one another.
Follow ink manufacturer’s directions for curing time and temperature. Generally, polyester garments are cured at temperatures under 320°F. To achieve this, you may need to use a catalyst in your ink to reduce the curing temperature. Before going into production, allow a printed shirt to rest overnight and wash it to ensure that you have consistent coverage, good adhesion and no signs of dye migration.