Avoid the five biggest problems with domed labels by understanding the most common issues, how they are caused and what to look for before ordering.
Domed labels are over 20X thicker than un-domed labels (0.07 thick vs. 0.003) requiring special adhesives designed for this difference in thickness.
Imagine spreading a thin layer of household glue to a sheet of glass and trying to mount the glass to rough concrete. The glue will not work because it only touches a few points of the concrete.
Now, spread the same thin layer of glue onto a sheet of newspaper and press the paper onto the concrete. The paper will hold because the paper flexes between all the peaks and valleys of the concrete increasing the surface area of the adhesive.
Heres the problem label manufacturers make trillions of labels every year (thats trillions as in 1 with 12 zeros). These trillions of labels are made with very thin adhesive (about 0.0005 thick). Label companies stock thin adhesives made for un-domed labels. These same companies may also offer domed labels and you can imagine what adhesive they use.
Domed labels simply require more adhesive to flow into the nooks and crannies of the mounting surface. DomeTag only makes domed labels and only stocks adhesives up to 14X thicker specifically and only for domed labels.
Domed labels are made by pouring an exact volume of liquid on top of a traditional label. The liquid flows to the edge of the label and cures for about 12 hours. Unless the dome is perfectly level, the dome will be thicker on one side than the other.
If you order domed labels from a traditional label supplier, do you really think they have facilities designed to keep millions of domed labels perfectly level until they are fully cured? Not likely! DomeTag manufactures only domed labels with manufacturing equipment, facilities and processes designed to maintain perfect level during the full curing process.
Heres the test: compare a DomeTag Brand Label to an off-brand dome by checking the thickness around the full edge of the label. Youll find that our domes maintain the same thickness uniformly.
As described above, the liquid dome must be poured in an exact volume to allow the dome to flow to the edge of the label. Too much liquid and the dome flows over the edge of the label; too little and the dome stops before the edge. DomeTag is the most popular doming company in the United States because we only make domed labels. Our equipment is custom-made and calibrated for consistent and uniform domes. The difference is easy to see.
Epoxy is an inferior polymer that continues to yellow, shrink, harden, curl and dull over time compared to the optically clear, flexible polyurethane used by DomeTag.
Epoxy is more popular because it is less expensive and does not require vacuum degassing or humidity controls. Domed labels made by small-time producers and facilities with few quality controls give the dome label industry a poor reputation by using epoxy resin instead of urethane. Domed labels made in China are infamous for using low quality epoxy resin.
One common misunderstanding is to blame poor adhesives for domed labels falling off. The real problem is that epoxy domes shrink over time and the shrinking causes the dome to curl and lift off the mounting surface. In other words, even if the correct adhesive is used, domes still fall off because of the shrinking and curling of the epoxy.
Laboratories do a simple test to determine if a dome is made of epoxy or urethane. When held under a flame, epoxy will turn black and continue to burn even after the flame is removed. When urethane is held under a flame, it does not turn black and does not hold the flame after the torch is removed.
NOTE: Laboratories should have proper fire suppression and approved ventilation to conduct this test.
When uncured urethane comes in contact with moisture the result is bubbles.
Bubbles in domed labels can be caused by improper mixing or dispensing, but the main cause is water in the air at more than 40% relative humidity. Printers often add humidity to the air during production adding to the problem for printers that only dome as a side operation. Printed labels and liners need to be properly dried to remove moisture before doming with urethane.
Bubbles on the surface of the label are typically caused by high humidity. Bubbles inside the dome are more typically from improper mixing or dispensing. DomeTag specializes in only doming so the entire process is done in a controlled environment.