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1" Stainless Steel Ball Probe (P/1S)

ABSTRACT Over the past years, one objective of the PSA industry has been to identify a single, standard, reproducible test to easily measure the tack of a PSA. As a result, the industry has experimented with probe adhesive testers of various designs. Some of these testers have measured the tack force, that is, the maximum force recorded during the debonding of the probe from the adhesive. Others have suggested measuring the tack as a function of energy dissipation during the debonding process. Because of this ambiguity, the probe tack testers have not provided a better definition of tack than other conventional tack performance tests such as loop tack, rolling ball tack, etc. Another disadvantage is that the data generated by these testers has not been very reproducible due to inconsistent contact areas between the probe and test surfaces or the interference of the face material stiffness with tack measurements. Consequently, these probe tests have not been widely accepted as standard tools for measuring PSA performance.

The Avery Adhesive Test (AAT) discussed in this study has eliminated the disadvantages of the traditional probe testers. In the AAT, we modified an existing concept to develop a new technique. The major concept change involved recording and analyzing the entire stress-strain behavior of a probe test as first suggested by Zosel and Johnston. Earlier methods had reported a single value for tack force or tack energy. The ability to record and analyze the entire adhesive stress-strain behaviour was made possible by improved transducer and motor technologies, coupled with less expensive and faster computers. Other improvements over the traditional testers include the use of a spherical probe to ensure contact consistency and the use of double-side tape to mount the test sample such that the effect of facestock stiffness on test data is minimized.

The advantage of the AAT is that the method can be used to specify adhesive performance by analyzing the multiple parameters extracted from the force-distance AAT profile. A second advantage is that the test can be used for QA/QC by profile pattern recognition software, an idea first suggested by Johnston. Finally, the method can also be used for R&D by analyzing the relationship between PSA molecular structure and the AAT profile.

Taken from: CHUANG, H. K., CHIU, C. & PANIAGUA, R. (1997). Avery Adhesive Test Yields More Performance Data Than Traditional Probe. Adhesives Age, September, 18-23.

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