Friday, April 17, 2015

The Differences Between Polyurethane and Vinyl Films

Many in our industry use the all-encompassing term “heat transfer vinyl” to refer to any heat transfer flex film.  The fact of the matter is that many of the heat transfer films on the market today are not vinyl at all. Much of what is sold today is polyurethane or a polyurethane blend.

The reason that I make this distinction is that there is a big difference between polyurethane and vinyl films.  What’s more, a 100% polyurethane film is also quite different than a polyurethane-based blended film. Let me explain the differences.

Polyurethane films are very soft and stretchable. There’s a reason for this. Polyurethane is comprised of very long molecular chains, which provide it with elasticity.  By comparison, vinyl is composed of molecules which are very rigid. 



100% polyurethane heat transfer films are much more elastic than plasticized vinyl films.


To make vinyl films more elastic, plasticizers are added to the formulation. Plasticizers are oils which can leach out of the film, every time the garment is washed. As the plasticizing oils leach out of the vinyl they can cause allergic reactions.  Plasticizers have also been linked to other medical issues, which is why some plasticizers have been banned under the Consumer Product Safety Improvement Act (CPSIA) for use in the manufacture of children’s garments.

As plasticizers leach out of a vinyl, the film increasingly becomes more rigid and brittle. Eventually, appliques manufactured from vinyl heat transfer films will crack.

Polyurethane films do not need plasticizers to make them stretchable. These films are naturally elastic. That’s why appliques made from polyurethane heat transfer films retain their flexibility and provide long-term service life. In fact, if garments are washed and dried properly, polyurethane appliques should last as long as the garment itself.  

Compared to vinyl heat transfer films, polyurethane films provide other desirable performance properties. Polyurethane is also more abrasion resistant than vinyl, which makes it ideal for punishing athletic applications. Used to decorate performance fabrics, polyurethane films provide the elongation and memory, allowing the appliques to stretch as the fabric stretches.

Caveat emptor

Be aware that not all formulations of polyurethane films are the same.  While all of the SEF heat transfer films are 100% polyurethane, many other competitive products are classified as “polyurethane based”.  These polyurethane based films are blends of polyurethane and vinyl. Because these blends contain PVC, they may not be CPSIA or OekoTex Standard 100 compliant.

With the addition of vinyl to their formulations, polyurethane-based films are also typically stiffer, less elastic and not so durable as 100% polyurethane.

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.


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ABOUT SEF: For more than 35 years, SEF has provided the screen printing and garment industries with high quality flex films and flock films. Manufacturing at SEF is totally integrated. The factory formulates, casts and adhesive coats its own polyurethane (PU) films. SEF even manufactures its own flock fibers. With a corporate commitment to a greener environment, all of its film and adhesive formulations are water based. This ensures that no solvents pollute the atmosphere. Its only emission is water vapor. Today, SEF is recognized as a leading producer of heat transfer films for use in the fabrication of heat press appliqués for textile decoration. Its ultra-thin polyurethane films and super soft flock films are easy to plotter cut and digitally print.

For More Information About SEF Americas:


14476-201 Duval Place West
Jacksonville, FL 32218
904-423-0211 - Phone
904-423-0899 - Fax
844-720-9600 - Toll Free

© 2015 Jim Hingst

1 comment:

  1. nice blog ! author has differciated Polyurethane and Vinyl Films very nicely. thanks for sharing this type of blog related to heat transfer topics.

    ReplyDelete