Specifying label stock for your terminally sterilized package can bite you in the derriere’ if you are not a bit of a pool player. In other words you need to think ahead a couple steps, have some background history at your disposal, and be willing to brave the disapproving gaze of the quality folks, who would put a tolerance on your underwear if they thought they could get away with it. There are many ways to specify material, label face stock and liner for this post, that will both guarantee consistent and functional labels on your package and also ward off unnecessary ECO/ECR print changes.
As most of us know, the FDA and other entities interested in device labels have two simple requirements, that the labels be legible and affixed. They can’t fall off and you gotta be able to read em. This would apply to the label facestock, the actual part with adhesive that sticks to the package. There are a number of ways to describe label face material but the most common is to throw out basis weight of the paper sheet. It is also by far the most useless and non descriptive identifier in use, but it’s on literally every print that comes across my desk. Why you ask? Because that’s the way it’s always been done. My guess is that two out of 100 people actually even know what basis weight is. I think it was invented by Johannes Gutenburg when he had to carry paper on his back to his new fangled printing press. 50# label refers to the weight of 500 sheets of 25” x 38” paper. Can we verify that weight at Advanced Web? Nope, it has adhesive on the back of it. Can you verify that at your incoming inspection area? Most certainly not, for the same reason. Is the number useful for anything other as a nice number for people who like to quantify things? It’s as useless as teats on a boar hog, as my Grandpa Larsen would say. There are many other attributes that are more useful such as opacity, machine and cross direction strength, brightness, and the actual thickness of caliper, yet these rarely are seen on a print. The other main pitfall of spec’ing label material is when the packaging engineer takes a data sheet from his helpful label vendor and just plugs in what he sees on that data sheet. Invariably the paper company gives the sheet an exciting marketing/trade name like Scanrite, Laserbrite, JetLaser, TransTherm, or some other brilliant marketing designation that they are sure will make the sheet sell like hotcakes. The name shows up on the print and 9 months down the road these same marketing wizards decide to change TransTherm to Transtherm II with a effective transition time from the original to the new sheet of about a month. We often have to furnish a certificate of conformance on the label material and have to certify the actual material, which is no longer TransTherm but TransTherm II (actual case here folks). We all know what happens then. A flurry of paperwork and emails involving everyone from package engineering to quality to the janitor. Maybe there can be a deviation to use the ‘new’ stuff or maybe an ECO/ECR needs to be walked around in order to rescue the labels from the limbo that is quality hold. Using that trade name is like someone asking you to make a ‘Xerox’ of a document, ‘FedX’ a package, or grab a ‘Kleenex’ to blow your nose. Normal human beings realize that you want a copy, overnite air, and a tissue to clean your nasal passages, but we medical device people will immediately slam the brakes on. If you happen to have a Canon copier, a next day air deal with UPS, or a box of Puff’s you will not be completing any of those tasks in the medical device world because the documentation and cert no longer match the print and God knows what horrible, non compliant things would occur were you to proceed with your copying, shipping, or nose blowing.
How do we avoid these label specification traps? Two things: generic face stock specs that address the attributes needed for the label, and liberal use of the ‘nominal’ symbol, pictured above. Generally terminally sterilized device labels are printed by the label vendor with colored logos and such, and the variable data is filled in with either thermal transfer or laser printers at the device manufacturer. General requirements are typically a white sheet, somewhere in the neighborhood of .003” caliper for decent opacity and strength, and a surface that’s receptive to either thermal transfer ribbon or laser toner. When describing characteristics such as the useless basis weight or the much more useful thickness caliper, it’s instructive to know that those can also change with little advance notice and that there is a tolerance involved. A 46# sheet might switch to a 44# sheet from a different mill and have the same caliper. That’s where the magic and utility of the nominal symbol comes into play. I believe this symbol was created or maybe discovered by a shadowy, furtive, long time packaging engineer at a large device manufacturer in the northern hemisphere. Let’s call him GB. While this symbol is not included in EN 980 yet, it should be. That way, miniscule changes to attributes that don’t affect the form, fit, or function can be dealt with in an efficient and compliant manner. Thank you GB for this service to humanity. I probably owe you a beer.
The adhesive is the key part of the labeling system, the part that makes sure we meet that ‘affixed’ part of the requirement in CFR 21, Part 820 of the QSR, and I will write about that another time. The third and last part of the label sandwich is the liner. This is the part that you throw away, the part that keeps the adhesive from sticking to things you don’t want it to stick to and conveys the label from the adhesive coater to the converter to the device manufacturer. There are only three things you could possibly care about with liner. 1) Does it keep the adhesive from sticking to unwanted surfaces, 2)For laser printed labels, does it keep the label stock flat, and 3)For machine applied labels, is it strong enough to go through your equipment efficiently and without breaking. Since all liners perform the first task there would seem to be no need to spec anything other than a liner being present if you are not laser printing or machine applying the labels. Yet just this year I had a customer ECR come through changing a spec that called out a 40# liner to the more accurate 42# liner. If wasting engineering time and doc control time was an Olympic event they would be playing this company’s anthem as their corporate flag rose up the pole and their representative stood misty eyed on the medal stand.
Here are a couple examples of actual specs out in the device industry today. The first is what I call the time bomb spec, sure to blow up and cause angst, ECO/ECR’s, and feverish attempts to make anatomically impossible jumps through intimate body parts by people in several departments at both the label supplier and device manufacturer.
-Facestock :Fasson Lasercopyjet 56 Flex, 56 gm/m2 matte white, flexible, woodfree machine finished paper with good opacity, excellent aborption and toner bonding characteristics.
Liner: AT 45 (45gm/m2 )light weight woodfree white kraft paper based on TCF pulp
This would be a generic version of the same material:
Facestock: 45# (nominal) white laser toner receptive paper, .003” caliper (ref)
Liner: Lay flat liner suitable for sheet fed laser imaging
One calls out a painfully specific material with very rigid, inflexible characteristics. A change in any of those attributes would short circuit an attempt to issue a certificate of conformance. The latter material spec describes the general physical characteristics of the label paper needed to successfully meet those two FDA requirements of label stock, affixed and legible. If more device manufacturers used this approach it would result in a label product of equal quality, effectiveness, and compliance as well as drive dollars to the bottom line, dollars saved when wasteful non value added activities were eliminated from the labeling specification, documentation, inspection processes.
In two short weeks a number of us will be sitting in Albuquerque, New Mexico at the 2012 Heatlhpack event. This years IOPP Medical Device Techncal Committee meeting will include breakout sessions for the various subcommittees, including the Labeling subcommittee headed by yours truly. I hope lots of folks will choose to ‘caucus’ with us. Bring your ideas and feedback. I’ve also been researching and prepping for this event extensively and am part of the advance team for pre-event venue evaluation. Accordingly, I have assembled Dr O’s Guide to Albuquerque brewpubs and non chain, locally owned restaurants with interesting food. Those of you who joined me at Gus’ Fried Chicken and the Flying Saucer in Memphis know of what I speak. One of my goals as I careen through life is to avoid both light beer and Applebees. In fact for roughly the last 40 years I’ve religiously sworn off Light beer during the 40 days of Lent and will be unable to enjoy a Bud, Miller, or Coors light with any of my fellow packaging professionals. Shoot me an email and I will send you the electronic version of the list, complete with links, or visit us at Healthpack for your very own printed souvenir copy.