Heat can cause the dye in synthetic fabrics to bleed through heat transfer vinyl or the inks used in screen printing. This is called dye migration, or “bleeding.” Fabrics continue to trend toward polyester and other synthetic blends. Because of this, dye migration is front and center for today’s garment decorators. Heat transfer on synthetic materials is possible but requires special handling to avoid issues. This post will cover the ins-and-outs of dye migration and how to stop bleeding. After reading, you’ll be prepared to block dye migration head on.
What is Dye Migration?
Dye migration occurs when the ink used to dye the fibers of a polyester fabric are reheated to above 280°F. At this temperature, the inks are released from the garment’s fibers. When they are released the dyes will come through heat transfer vinyl and cause bleeding. This bleeding can happen any time the garment is heated – in a dryer or a hot car for example.
Dye migration will only happen in 100% polyester or synthetic fabrics or blends with a high polyester or synthetic content. It happens because of the dying process used to color these synthetics. Heat and pressure are used to dye these fabrics so heat and pressure reapplied may risk re-releasing the dye. This is especially true with sublimated garments. Use the most caution when using heat transfer materials on sublimated jerseys.
How to Prevent Dye Migration
The first step in blocking dye migration is to check the care label. It will tell you the percentage of each fiber in your garment. The higher the polyester count the more watchful you’ll need to be.
Next, test for bleeding using your heat press. Put the garment on your heat press. Cover with a kraft paper cover sheet. Heat apply for 10 seconds. With unstable inks, you’ll see ink residue on the cover sheet after transfer. The amount of dye migration will be related to the amount of ink residue on your cover sheet. This test isn’t fool-proof, dye migration is still possible, but it’s a good starting point for choosing, and then testing, the material you’ll use to adorn your garment.
Decorating Low Bleed Polyester
If your cover sheet has a little ink on it after you test it, you likely have a low bleed garment. You’ll want to use these tips and materials to decorate these garments. Always test your material first and check for dye migration before filling an entire order.
Cool down your heat press. To prevent dye migration on low bleed garments you can set the temperature of your heat press to the low side of the material’s recommended temperature range. This will reduce the heat activation of the dyes in the fabric.
A dark color HTV is also an option for low bleed polyester fabrics. Any dye migration will not be visible on the HTV.
CAD-CUT® Thermo-FILM® Heat Transfer Vinyl does not block dye. Yet, with its opacity and thickness, it will curb dye migration in most low–bleed fabrics.
Decorating High Bleed Polyester
High bleed, fully sublimated garments require the most care to prevent dye migration and ruined garments. Once, decorators had to refuse to personalize these kinds of garments because dye migration was unavoidable.
CAD-CUT® Silicone Dye-Block™ is the answer for dye migration while using a heat press.
This stretchy transfer vinyl applies at a low temperature with no scorching. It also blocks dye on sublimated fabrics. With Silicone Dye-Block™ you can be sure your jerseys will be done right every time.
Hotronix® Heated Lower Platen is the latest innovation from Hotronix®. It provides heat on the underside of a threaded garment. This reduces the risk of both scorching and dye migration. When paired with materials like Silicone Dye-Block and AquaTru Dye-Block, the Heated Lower Platen helps to reduce the risk of dye migration.
Decorating with heat transfer on synthetics presents challenges for the garment decoration industry. But with the growth and popularity of performance wear and other polyester and synthetic blends, it’s an inevitable one. Be prepared by reading garment labels, testing garments, and using the right materials.
Learn more about dye migration with this downloadable ebook, The Dye Migration Handbook.