SIR! What Is It Good For?

Despite the capital “SIR”, this is not heat transfer film for enthusiastic soldiers. S-I-R is an acronym for Sublimation Ink Resistant. That means this particular film is designed to resist the migration of dye or ink from the garment to the film when applied to CAD-cut letters and graphics. If you are not familiar with this problem, you’re probably using good quality cotton shirts. But if you’ve ever applied white letters to a black shirt and found the letters turning gray, HotMARK SIR product is for you.

Dye and Ink Migration

What causes white letters to turn gray or vivid yellow to become brown? It’s called color migration, and it happens when high temperatures generated by a heat press activate the dye with which the garment was colored. This color then migrates onto the transfer film and darkens it slightly. The two most likely culprits for this phenomenon are garments decorated with dye sublimation and non-decorated garments manufactured with thermal reactive dyes.

Sublimation Situation

A dye sublimated garment should be pretty easy to spot and is not the most common problem. But if you are creating a custom garment that requires a combination of dye sublimation and a CAD-cut accent, you could have some of the dye reactivated when you press the accent onto the sublimated garment. Using EnduraTEX HotMARK SIR will prevent that so you’ll get a nice, high contrast appliqué on top of your sublimated design.

Thermal Reactive Dye Can Make You Cry

The more common problem is caused by applying CAD graphics to a shirt that has been colored at the factory with a thermal reactive dye. This can be caused by low-quality imported garments, but is also commonly seen in polyester. As noted above, the heat of the press activates the dye and darkens or colors your appliqué, reducing the contrast and possibly ruining the design. The cure for this migration malady is HotMARK SIR.

How Does It Work?

Like HotMARK 70, EnduraTEX HotMARK SIR is a soft polyurethane film on a transparent polyester liner. The difference between the two is in the construction of the face stock. SIR has an extra layer that acts as a barrier between the garment and the visible surface. A downside to SIR is this solution makes it a thicker film. HotMARK SIR is 4.3mil (110 microns) thick, compared to only 2.2mil (50 microns) for HotMARK 70. Since it is twice as thick, obviously a HotMARK SIR appliqué is not going to be quite as soft as one made from HotMARK 70.

The SIR advantage is higher contrast and consistent color. Since color migration is most often seen in light colors, EnduraTEX HotMARK SIR comes in white, yellow, orange, and red. It’s available in the same 11, 22, and 66 foot roll lengths as the rest of the EnduraTEX product line. Using any of these colors will provide a vivid, high-contrast graphic both you and your customers will love.