Heat during the application process can cause the dye in polyester or other synthetic fabrics to bleed through heat transfer vinyl or plastisol inks when screen printing. Because of this, dye migration is front and center for today’s garment decorators as fabrics continue to trend toward polyester and other synthetic blends. Heat transfer on synthetic materials like polyester is possible, but requires special handling to avoid issues.
What is Dye Migration?
Dye migration, or bleeding as it is most commonly called, occurs when the ink used to dye the fibers of a polyester garment are reheated to temperatures above 280 degrees. At this temperature the inks are reactivated and released from the garment’s fibers. When they are released the dyes will come through heat transfer vinyl and cause discoloration, like a faint red (or pink) number on a red jersey. This dye transfer 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 because of the dying process used to color these synthetics or a sublimation process. Heat and pressure is used to dye these fabrics, so heat and pressure reapplied may risk re-releasing the dye. Use most caution when using heat transfer materials on sublimated jerseys in particular.
How to Prevent Dye Migration
The first step in preventing dye migration is to check the care label. It will tell you what the fiber content of your garment is, including percentages of each kind of fiber. The higher the polyester count the more cautious you’ll need to be when choosing a heat transfer to apply.
Next, test for dye migration using your heat press. Put the garment on your heat press, cover with a kraft paper cover sheet and heat apply for 10 seconds. With unstable inks, you’ll see ink residue on the cover sheet after application. 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 decorate your garment.
Decorating Low Bleed Polyester
If your cover sheet has just a little ink on it after you test it, you likely have a low bleed garment. You’ll want to use the following tips and materials to decorate these garments, but always test your material first and check for dye migration before completing an entire order.
Cool down your heat press. To prevent dye migration with your heat press on low bleed garments you can set the temperature as low as possible (within the material’s recommended application temperature range). This will reduce the amount of heat activation of the dyes in the fabric.
A dark color heat transfer vinyl is also an option for decorating 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, but because of its opacity and thickness, it will inhibit dye migration in most low–bleed fabrics.
CAD-CUT® Sublistop, CAD-PRINTZ®, or CAD-COLOR® are other products that may inhibit dye migration on low bleed garments because of a lower application temperature. Remember, testing your application is important to be sure your particular garment isn’t going to bleed through your transfer.
Decorating High Bleed Polyester
High bleed, fully sublimated garments require the most care to prevent dye migration and ruined garments. Previously decorators had to refuse to personalize these kinds of garments because dye migration was unavoidable — unless using a dark colored heat transfer vinyl which would hide the ink showing through.
After years of research and testing, Stahls’ now has options for personalizing fully sublimated, high bleed garments.
AquaTru™ Dye-Block™ is the answer to the industry’s growing need for a true dye blocking formula for application on sublimated and synthetic garments.
Developed in the Stahls’ laboratory, AquaTru™ Dye-Block™ is a specially formulated proprietary Heat Transfer Ink that not only blocks dye on even the highest bleed garments, it’s also soft and lightweight with excellent stretch and rebound.
It comes in 19.5″ x 26″ heat transfer sheets for use with your vinyl cutter and stock numbers in two popular fonts for the sports market, Varsity and Team US. They’re perfect for popular sublimated jerseys for sports uniforms.
CAD-CUT® Silicone Dye-Block™ is the first silicone based solution for dye migration using heat transfer technology.
This stretchy and pliable material applies at a low temperature for a professional application with no scorching. It also fully blocks dye on sublimated fabrics so you can be confident your jerseys will be done right every time.
Hotronix® Heated Lower Platen, the latest innovation from Hotronix provides heat on the underside of a threaded garment, to reduce the risk of both scorching and dye migration. When paired with materials meant to block dye migration, 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.