Tackiness is one of the most important properties of pressure sensitive adhesives (PSA). Tack is the property of a pressure sensitive adhesive to adhere to a surface under very little pressure. Pressure-sensitive hot melt adhesives have the ability to quickly wet the surface with which they come into contact.
Test method for stickiness
There are four test methods that are used around the world to evaluate the tack of a pressure sensitive hot melt adhesive.
"Rolling Ball Tack"
The tack value can measure the relative adhesion performance for different PSAs along with other properties such as
"Adhesive error temperature"
The loop tack is now the most reliable and most used. This test method has proven that it produces reproducible and consistent data. For self-adhesive products such as tapes and labels, loop adhesion is the most commonly used published tack parameter. Microprocessor-controlled loop tack testers have independently increased the reliability of loop tack tests.
Rolling ball tack
The rolling ball tack test is a simple test result and provides unique values that cannot be compared to other tack tests. A high loop tack is not associated with a low rolling ball tack. The rolling ball tack method is a very good practical test method for direct quality control at the production site to check the consistency of a self-adhesive coating.
This test method has mostly been used as a test that measures adhesion to a person's fingertip. The test values were not stable and appeared to be too sensitive to fluctuations in coating weight and sample preparation.
A loop tack test has been shown to be more reliable than a quick sick test. A quick stick test setup is difficult to manufacture because a moving substrate must be glued and then the force measured to tear the substrates apart. A peel adhesion test provides better additional information about the properties of a pressure-sensitive hot melt adhesive.
Finger tack test
Fingernails are commonly used as a "human test" that does not require any equipment other than a human. Although experts believe in their own fingertack methods, it is a subjective, unscientific test. No PSAs, with the exception of PSAs in contact with the skin, are glued to human skin. The finger stick test is faced with many variables, such as skin roughness, moisture, temperature and fat. You'd better use your eyes to read a technical sheet.