Heat Pressing on Dye Sublimated Fabrics

 What is Dye Sublimation?

Most polyester fabrics, such as many of the popular “Performance Garments”, are dyed using a sublimation process. The dye sublimation process uses high heat to permanently   fuse   the colorant   into a polyester fabric.

For heat setting dye sublimation inks to polyester materials, such as textiles, high temperatures in the range of 400°F (204°C) for 45 seconds are typically required. 

Heat serves two critical functions in this dying process.  First, the heat causes the pores of the polyester fabric to open up, so the material can accept the dye.  And second, the heat converts the solid ink dye on a transfer sheet into a gas.

Under pressure of the heat press, the gaseous dye is forced into the open pores of the polyester.  As the temperature drops, the pores close up capturing the dye inside of the bonds to the substrate. 

The sublimated color is very durable because the dye becomes an integral   part of the fabric, rather than a colorant on the outside of the fibers of the fabric, which can bleed and fade.  Sublimated fabrics can be washed again and again, without losing the vibrancy of its color.

Dye Migration Can Discolor Heat Transfer Appliques

There’s one slight catch, though. When you heat press an applique onto a sublimated garment, the high heat can cause the pores of the polyester to reopen releasing the dye in the fabric.  These dyes can then migrate and discolor an applique.

Without an anti-migration blocking layer, dye migration can discolor an applique. In the photo above the white polyurethane film turned a light grey within 72 hours of heat pressing.

Discoloration resulting from dye migration does not occur immediately. Instead it is a gradual process, which may take as long as 72 hours to occur.  For example, a white applique heat pressed onto a black sublimated garment is likely to turn grey over time.

Heat Transfer Films with an Anti-Migration Layer

To prevent discoloration, many of the SEF heat transfer films incorporate a SubliBlock (SBB) ink migration blocking layer.  This second layer of  film is a dye blocking solution that  prevents discoloration of an applique caused by dye migration, regardless of whether a polyester garment has been dyed or dye sublimated.  While this second layer adds to the thickness of the applique, it is much more effective in preventing discoloration compared to other products, which utilize adhesive additives to perform the blocking function.

Heat pressing heat transfer films at high temperatures can exacerbate the dye migration problem. For this reason, SEF Americas SBB Products, such as Tatoo SBB and FlexCut Sticky SBB, are designed to be heat pressed at slightly lower temperatures of 295°F (146°C). Other heat transfer products on the market, which are designed for decorating dyed polyester are heat pressed at higher temperatures, such as 330°F (165°C).

SEF heat transfer films, which incorporate the  SubliBlock ink migration blocking layer include:

• FlexCut Sticky SBB, a polyurethane film with the SubliBlock layer for plotter cutting.
• Tatoo SBB, a digitally printable polyurethane film with SubliBlock.

FOR TECHNICAL SUPPORT: SEF Americas provides a toll-free technical support service at 844-720-9601. NOTE:  If your call is not answered by a tech support person during normal business hours, 8am to 5pm EST (Eastern Standard Time), please leave a message and we will do our best to return your call within an hour.  Should you need to contact us after business hours, an alternate tech support number is 480-987-8028.  You can also get answers to your technical questions by emailing: techsupport@SEFamericas.com.

For More Information About SEF Americas:

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© 2015 Jim Hingst