How Accu Dyne Test Marker Pens Work
ACCU DYNE TEST™ Marker Pens have a valve tip applicator that separates the testing part of the pen from the fluid storage part of the pen. This prevents wicking from the substrate. Pressing the tip firmly down opens the valve so that fresh fluid floods the tip. This flushes the tip clean, and allows the tester to lightly pass it over the sample to accurately determine dyne level. The time it takes the test solution to form beads on the sample surface determines the results.
Accu Dyne Test Marker Pen Features
- 16 Standard levels, from 30 through 60 dynes/cm
- Specifically designed for fast, accurate on-line use by printers, coaters, and laminators Also ideal for process control or field use by suppliers of film, sheet, coated board, inks, coatings, and adhesives
- Spring loaded tip meters fluid feed and guards against contamination
- Reliable enough for many R & D and lab applications
- Hundreds of tests from each marker
- Usable on virtually all smooth non-absorptive substrates
- Six month shelf life; mix certifications provided with every order
- Specify any combination of dyne levels and quantities you require (minimum order four pens)
- Conveniently packaged in ready to use setup boxes
IMPORTANT SAFETY NOTICE:
The fluids contained in ACCU DYNE TEST™ marker pens are considered hazardous materials. Avoid contact with skin. Use with adequate ventilation. Avoid contact with eyes. Pregnant women should not perform this test. For further information, refer to product MSDS or call Diversified Enterprises at 800-833-4644 or (603)543-0038. For the results of this test to be meaningful, the following four points are absolutely essential and must be followed:
- Do not touch or in any way contaminate the surface to be tested. Dirty surfaces lose their wettability.
- Do not use contaminated or outdated ACCU DYNE TEST™ marker pens.
- Never retest the same location on a sample; move along the sample, or pull a new one.
- Store and use ACCU DYNE TEST™ marker pens at room temperature.
ACCU DYNE TEST™ PROCEDURE
1.0 Materials/Equipment
1.1 ACCU DYNE TEST™ Marker Pens
1.2 Subject Material
1.3 Clean Level Test Area
1.4 Thermometer and Hygrometer
2.0 Method
2.1 Pull test sample. Be sure to pull a good specimen; surface aberrations cause poor results. For extruded film, one entire web cross-section should suffice. Do not touch the surface.
2.2 Place the sample on a clean, level surface. If necessary, anchor the edges to avoid curling or other deformation.
2.3 Record ambient temperature and relative humidity. If sample temperature differs from ambient, allow it to stabilize.
2.4 Test at least three points across the sample; 1/4, 1/2, and 3/4 across the film section. It is good practice to test the outer edges as well. For non-film materials, test locations must be determined in-house.
2.5 Determination of Wetting
2.5.1 Choose an ACCU DYNE TEST™ marker pen of a dyne level you believe is slightly lower than that of the test sample.
2.5.2 Press applicator tip firmly down on subject material until the tip is saturated with ink.
2.5.3 Use a light touch to draw the pen across the test sample in two or three parallel passes. Disregard the first pass(es); to flush any contamination from the tip, and to ensure that the test fluid layer is thin enough for accurate measurement, evaluate only the last pass.
2.5.4 If the last ink swath remains wetted out on the test sample for three seconds or more, repeat steps 2.5.2 and 2.5.3 with the next higher dyne level marker. if the last ink swath beads up, tears apart, or shrinks into a thin line within one second or less, repeat steps 2.5.2 and 2.5.3 with the next lower dyne level marker. if the ink swath holds for one to three seconds before losing its integrity, the dyne level of the marker closely matches that of the sample.
Accuracy and Precision
This is a relatively accurate surface energy measurement technique; used in standard 2 dyne/cm increments, ACCU DYNE TEST™ marker pens can generally produce results with a precision of +/- 2.0 dynes/cm. Repeated use of ACCU DYNE TEST™ marker pens should enable testers to estimate surface energy to within +/- 1.0 dyne/cm.
Investigation of Discrepancies
To investigate discrepancies between obtained and expected results, a more precise measurement method should be considered; application of ACCU DYNE TEST™ surface tension test fluids with cotton swabs (per ASTM D2578-84) or by use of a drawdown rod is recommended. Alternatively, if results are suspect, replicate the test with a set of unused markers. This test has proven itself on a wide variety of substrates; it is, however, theoretically more prone to contamination than some other techniques. For this reason, even in the absence of unexpected results, you should establish a quality assurance plan which calls for regular audits during the phase-in stage of ACCU DYNE TEST™ marker pen use.
The effect of all changeovers from one substrate to another should be monitored especially closely. Slip and other additives tend to bloom to the surface of extruded sheets and films; transferring surface-active additives from one material to another can have a profound effect on surface energy measurement. In general, once you demonstrate that a switch from substrate A to substrate B has no effect, it is safe to assume that future changeovers from A to B will act similarly. Thus, the frequency of backup audits decreases over time.
Finally - A Few Qualifying Words
Surface energy is critically important to many converting operations. Unfortunately, it is not the sole determinant of product suitability. Other factors, such as surface topography, coating rheology, and chemical incompatibility, must also be considered. This is why broad-based communications with vendors and customers is so important. But at least by systematically measuring substrate surface energy, you will have a sound starting point from which to resolve other problems which may arise.
1 Annual Book of ASTM Standards, Wetting Tension of Polyethylene and Polypropylene Films. 2 Annual Book of ASTM Standards, Conditioning Plastics and Insulating Materials for Testing. * ethyl cellosolve is a registered trademark of Union Carbide Corp. for ethylene glycol monoethyl ether (2-ethoxyethanol).
This report is provided by Diversified Enterprises, 101 Mulberry St., Suite 2N, Claremont, NH 03743. It is intended to provide quality control information for converters and others who need to measure surface energy. We believe all information contained herein is accurate. Diversified Enterprises will not, however, under any circumstances by held responsible for any losses or damages incurred by any party using this report.
ACCU DYNE Testing — Applications and Tips
Accu Dyne Test Pens - The Basics
- Whenever feasible, test with supplies, samples, and ambient temperature at 20o to 25oC. If this is impossible, it is advised that a test study be run to relate temperature variations to numerical results. Keep test supplies at ambient temperature at all times.
- Test fluids or markers which have turned green are no longer reliable. We guarantee against this up to the expiration date (five months for fluids, six months for test markers).
- Never leave bottles or markers uncapped! Evaporation, water vapor, and airborne contaminants all affect dyne level, and can invalidate them long before expiration.
Accu Dyne Test Pens - Specific Applications
- Film extruders should test extensively — every roll from every machine without fail. Potential product liability and customer satisfaction losses far exceed the cost of an effective QC program. We strongly recommend using test fluids, preferably with the ACCU DYNE™ Applicator or a #3 metering rod. Alternatively, ACCU DYNE TEST™Marker Pens can be used, with laboratory contact angle tests used as a backup audit.
- Remember that dyne level decay is extremely rapid directly after corona treatment. A virtually immediate loss of 10 dynes/cm is possible! This is due to contact with process rolls (especially heated metal ones), surface blooming of additives, and interfacial transfers between treated and untreated surfaces within the finished, wound roll. If you are a slitter, rewinder, or extruder, either test far downstream in the process, or increase your specification to account for greater losses before your customer tests at incoming inspection.
- It is often possible to identify patterns of treatment variation on a sample piece by doing a full-size drawdown. Methodical troubleshooting analysis will often lead back to the specific cause. For example, increasing treatment across the roll suggests the treater electrode is misaligned to the roll; periodic variations along the web may relate to non-concentricity.
- An easy test for back-treat on PE or PP is to use a 34 dyne/cm ACCU DYNE TEST™ Marker Pen. Any wetting — even for less than two seconds — indicates some treatment.
- Printers, coaters, and laminators should pull samples and perform the test as soon before the print station (or similar) as possible. It may be worthwhile to dyne test the roll before it goes on the machine, and compare these results to material which has run through the web handling process to the print station. This will indicate the treat loss attributable to process roll contact and web handling.
- Polyester film which reads consistently below 42 dynes/cm is almost certainly "print primed." This chemical process actually decreases the surface energy a bit, but makes the surface attractive to a far broader range of compounds used in inks and coatings.
Test Cleaning Systems
- Use the dyne test to monitor cleaning systems. The surface energy of metals is much higher than that of surface contaminants; thus, the higher the dyne level, the cleaner the part is. Always use test fluids to measure cleanliness — repeated exposure to contamination will eventually overwhelm even our spring-loaded valve tip markers.
- The presence of mold release on many plastic parts can be similarly identified. Again, be sure to use test fluids for this application.