Hot Stamping Foil Adhesion - Assist With Choosing Completely different Types
Hot stamping foil adhesion is measured in plenty of different ways, and there's a lot of false impression about what every test actually measures. Take the straightforward scratch take a look at for instance. Is that a definitive adhesion check or simply a measure of the hardness of 1's fingernail?
In actual fact, most adhesion assessments carried out are comparative relatively than a real measure. In case you have two foils on the identical substrate, each blocked at the similar time, then you'll be able to check their comparative resistance to your fingernail, assuming that you don't subconsciously scratch tougher on that you simply wish to fail. That is more frequent than you would possibly suppose, which is why a true scientific measure of adhesion is most popular.
Nonetheless, such measurements are rare, and there is nothing that might realistically be routinely carried out by a commerce blocker or printer. Even a rub or abrasion tester isn't testing adhesion as a lot as the hardness of the foil floor. The so-called 'Scotch tape' check is generally probably the most extensively used, but there are such a lot of variables involved, that again that is usually not definitive until precisely the identical tape is used each time.
Other than the adhesion of the foil itself, the amount of wax launch applied can significantly have an effect on the adhesion and abrasion resistance of a hot stamping foil as it's tested. Hot foil can be made using all kinds of waxes, and isn't current within the type of a coherent separate layer. The wax layer is generally utilized by direct gravure, and is just around 0.005 gsm (grams per square metre) when dry.
The solvents used within the subsequent lacquer or prime coat are generally fairly aggressive, and despite the fact that have a tendency to not dissolve the wax when cold, will invariable strike by the wax layer instantly on coating, and likewise in the drying tunnel. The result's a wax rich resin layer at the carrier movie interface (usually polyester) that turns into progressively more wax poor the deeper into the lacquer layer - i.e. the additional the space from the polyester the place the wax layer was originally utilized, the less wax can be intermixed with the resin.
After blocking, the wax within the resin tends to rise to the surface. Though some wax might be at the surface of the foil instantly on hot stamping, this will improve with time as it migrates by way of the lacquer layer to the floor. Hence, abrasion resistance improves with time and your take a look at results will subsequently differ in keeping with how lengthy after blocking you take a look at the foil.
The identical might be true of the Scotch tape take a look at: the surface will turn into rising much less receptive to the tape because the wax concentration increases. What you might be measuring, then, is the adhesion of the tape to the wax-rich surface relative to the adhesion of the new foil to the substrate it's blocked to.
There is in fact a lot more to it than just that, but it indicates that what you may need thought was a simple test is, actually, not so straightforward. There are several different properties of a hot stamping that affect its perceived adhesion, too many to discuss on this article. Nevertheless the ideas involved are fascinating and value finding out as a result of they will shed light on a number of the issues you might need encountered on your press.
Sometimes understanding why a problem happens can provide you an concept of the solution. Nonetheless, I'll finish of with a number of questions which have little to do with options however extra to do with the testing itself. If you adored this article and you would such as to get additional info pertaining to www.Hotprintusa.com (www.digimarkcentral.com) kindly check out our own website. How many people go around testing their greetings cards or wine labels with a chunk of sticky tape? Is your testing associated to the top use of the foiled article, or carried out solely as a result of it is in the testing specification?
Good scorching stamping foil adhesion is ceaselessly wanted, however would you sacrifice efficiency and pace in an effort to use a sizzling foil that stands up properly to a bit of sticky tape after foil blocking?