Think of the relationship of ink to substrate as you would shampoo to scalp. If the wrong type of shampoo is used, it could result in dandruff. Likewise, if the wrong ink is being applied to a substrate the ink can fail with the result being the ink flaking off, much like dandruff. Fortunately, there are tests that can help identify both issues.
To test your scalp for flakes you can perform the scratch test. For the most accurate scalp scratch test results wear a black t-shirt and use a black light to identify debris while scratching. Signs that indicate this test is necessary are failed pickup lines that are obviously irresistible, kids walking behind you in the summer singing “its beginning to look a lot like Christmas,” and other similar scenarios. When experiencing ink flaking, with uncured, or easily ablated inks, performing ASTM F2252-03, the tape test can determine if ink to substrate adhesion is acceptable. Poor ink or coating adhesion can affect the readability, functionality, and even cause contamination. The last thing any company wants is a label in-line or in the field with potential of failing inks. Whether there is a possibility for that ink to flake and contaminate an OR environment, make a critical instruction unreadable, or cause a cosmetic malfunction, the ASTM F2252-03 tape test can help identify these risks upfront.
There is much more behind the ASTM F2252-03 test than just a piece of tape and a mini tug-o-war contest. To avoid poor results it is necessary to be as consistent as possible in performing the test. The ASTM F2252-03 test only requires 0.75-1.0″ wide 3M #610 tape for testing water based inks, 3M #810 tape for testing UV inks, and a mutual understanding of how to use the tape when testing. Having an understanding at both the printer and the end user about how the test is performed and how to interpret the results is critical in making this an effective and valuable test method.
Developing that standard conditioning test is important. Typical things to consider are as follows:
- An adequate sample size to be tested should be determined
- Conditioning consistency of the sample; ambient temperature, moisture exposure, ink cure time, amount of time tape is applied, etc.
- The substraight age and properties remains constant. (Note; the same test on a one year old material has potential to vary significantly from a three year old material. Surface energy treatments can diminish over time.)
Here is how to administer the test:
- The test should be completed on a flat surface with no wrinkles, creases, or folds.
- Cut a piece of #610 or #810 tape to use. When sizing the piece of tape try to keep the length less than 12″ to make the handling easier.
- Once sized, apply the tape to the surface of the coated substrate with your finger or thumb being sure to avoid causing any wrinkles or bubbles.
- Make certain the set up time for the scotch tape is consistent. Let’s call it 10 seconds for this example.
- While holding the sample down peel the tape off at a 120-150 degree angle with an even motion at approximately 12 to 18 inches per second. For those of you who don’t know how fast 12 to 18 inches per second is, you should recall the Tape Test you used to administer on your younger siblings. The 12 to 18 inches per second is about the speed you removed the duct tape at where it inflicted pain but didn’t rip their lips off. I always remember my tape tests working.
- Examine sample for ink flaking.
- Document the results and save the samples.
I suppose your question now is what to do if your tape looks like it just picked up half of the confetti from Bourbon Streets Mardi Gras celebration after the Super Bowl? If this occurs be sure to communicate that all possible variables have been standardized. Then it will be in the producer’s hands to provide the user with an adequate solution. This could be one of any of the following things:
- Increase the allowable cure time for the inks prior to performing the tape test.
- Increase the surface energy (AKA Dyne Level) of the material by using Corona treatment, material primer, a different manufacturer’s raw material, ect…
- Check the inks being applied. Resins for film substrates are usually softer than those used on paper to enable better adhesion. Be sure the right one is being used.
- Switch the inks being applied. For example, Water based to UV
Switching shampoo’s to get rid of dandruff seems simple, but just changing the shampoo doesn’t necessarily mean the dandruff will go away. It’s important that the right switch is made to eliminate the flakes. This is very similar to ink adhesion issues. There are a lot of variables and because the issue has been identified doesn’t mean there is a clear cut solution. Use the ASTM F2252-03 tape test as an indicative measure and, if there is a failure, work closely with the printer until the test is passed.