Find out how to distinguish amoung the varieties of laminating, the films on the market today and learn what criteria to consider when matching overlaminates with your applications.
Up front, thermal films seem less expensive because they do not require a liner. The downside is that laminating equipment for applying these films is more expensive because thermal films require laminators that provide heat of up to 250°F or more in order to activate the adhesive during the laminating process.
Essentially, thermal films are made up of two parts: the facestock (most of-ten polyester) and the low-melt adhesive. The construction of this type of film is usually described using a ratio of polyester to adhesive. For instance, a 3-mil film may be described as 1:2, meaning 1-mil polyester to 2-mil adhesive.
Thermal laminating films are a little more difficult to work with than pressure-sensitive films. Users of ther-mal films have to balance a number of factors during the application process. For example, the addition of heat, combined with two already existing variables, tension and pressure, increases the potential for user error. Beyond this, improper tension control is one of the biggest causes for error. Many laminator operators run the films through laminators under excessively high tension levels, resulting in curl, boat-waking (machine-direction lines running at a slight angle away from the nip roller), or other strange phenomena. When it comes to tension control, always remember: Less is better.
That's not to say perfecting this balance isn't possible. Many laminator operators who use this method of laminating are able to hone their process over time and ultimately have very few errors.
It is also worthwhile to note that, in general, pressure-sensitive laminating films tend to be more expensive than thermal films upfront. But pressure-sensitive films do not require heat for application, nor do they require encapsulation (thermal films must be applied to both sides of a graphic, not just one.). These factors can make pressure-sensitive films a less expensive choice overall.
Applying the knowledge
Now that you've seen the types of laminating films available, you should be able to solve for your "x" factor. It's true that all of these variables can get a little confusing and overwhelming, so the right answer may not be immediately clear. The good news is that there are people out there who know the materials and processes so well that you easily can find some help to get answers. Your suppliers will be glad to assist, so don't be afraid to ask.
About the author
Jeff Stadelman is the technical marketing manager for MACtac Graphic Products in Stow, Ohio. MACtac is a manufacturer of graphic films and other pressure-sensitive adhesive products. Stadelman can be reached by telephone at 866-622-8223 or by e-mail at MACtacgraphics@bemis.com.
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