When we see expiration dates or “best if used by…” on products, many of us ask ourselves if this is merely a suggestion or could there be some unwanted consequences by not using a product by this posted date.
When it comes to food product dating a "Best if Used By/Before" date indicates when a product will be of best flavor or quality; it is not a purchase or safety date. A “Use-By" date is the last date recommended for the use of the product while at peak quality. In our line of work we aren’t referencing food product dates, but how long can we continue to use a product with desired and consistent results. Our Technical Solutions Group (TSG) is often asked of the importance of these posted dates or questions if older inventory can be safely used. Here are a few of the products that people most frequently ask about...
Mounting (Stickyback) Tape
When considering 15 and 20 mil cushion mounting tapes, to obtain the best performance, use all products within 2 years from the date of manufacture. For thicker 40 and 60 mil cushion mounting tapes use within one year from date of manufacture.
Double-sided pressure sensitive adhesives have a shelf life to help ensure usability and adhesive performance. Over time, some adhesives can become dry, brittle, and lose their original performance properties. Although this occurs over time, it is helpful to have a date at which point the adhesive should no longer be used. In other cases, rolls of double-sided adhesive tapes can deform, ooze, pick and otherwise be very difficult to apply, despite retaining good performance relative to their stated performance levels. In this case, a shelf life is helpful for providing a guideline for the date after which the product is unlikely to be easy to use.
Proper storage and handling can lead to fewer usability issues and maximize usability over the recommended shelf life. Proper storage and handling recommendations include:
- Storage conditions of 60°F - 80°F (15°C - 26°C) and relative humidity (RH) levels between 40% and 60%.
- Avoid impacts to the edges of a roll when unloading from protective packaging.
- Storing unused rolls in the corrugated boxes they were shipped in and then stored in a vertical position with the end plugs and plastic wrap in place.
Photopolymer
While most raw sheet photopolymer goes through a 2-week green period in which the material should not be used because of the increased level of photosensitivity, for many polymer manufacturers the shelf life is 2 years. There are some polymer manufacturers that state 1 year as being safe, but all generally agree that if the user is performing adequate imagining, exposure, and processing test steps that material can be used beyond even 2 years. The key is to never assume older material is good and use existing platemaking settings with the hope of the same result. A very good practice is to always consult your photopolymer manufacturer as they understand best the idiosyncrasies of their product better than anyone.
Dyne Pens
The expiry date is generally 6 months from manufacture. Manufacturers typically do not ship pens that are older than 8 weeks. The 6-month shelf life is manufacturers best estimate of a time frame before which changes are likely to occur under correct storage and normal use. It is essentially a risk/reward decision, with the time frame set at the point where the risk may begin to appreciably increase.
3M Tape Primer 94
The shelf life of this popular product is 18 months from the date of manufacture when stored in the original container at 60-80°F (15-27°C).
- Keep 3M™ Tape Primer 94 in the original container.
- Transfer only a small amount into a work vessel for use.
- Keep the original container tightly sealed to avoid solvent evaporation.
3M AP86A Adhesion Promoter
Store this product at 60-80°F (16-27°C). Lower temperature storage will cause 3M 86A Promoter to gel. See Precautionary Information. The shelf life is 2 years from date of manufacture.
Precautionary Information: If gelling occurs, place the 3M™ Adhesion Promoter 86A into a zip-lock plastic bag to keep dry. Place the AP86A into a container of hot tap water (120-140°F [49-60°C] max.) for 30 minutes. The gels will go back into solution with no performance effects on the product.
Epson Inks
There is an ink expiration date on the box. This should be used as a general suggestion. It's more of a "best used by" date, though the ink will work after the date on box. For the "expired date" inks, just make sure to shake the cartridges for 60 seconds. 1-3 years beyond the noted date should be fine. 5+ years is beyond what we would consider reasonable.
It is recommended to shake the cartridges before inserting into a proofer regardless of how long they have been in storage. If inks are already in a proofer, and the proofer has not run in a couple of days, it is also recommended to take each cartridge out and shake them before start to printing. Dealers should never sell inks that are past their expiration date.
If you want to learn more about this subject, please feel free to reach out to us by calling 1-800-445-4017, or by e-mail at [email protected].
All Printing Resources has formed our Technical Solutions Group (TSG) to encompass our full range of expertise in all critical areas of the flexo process. This team is made up of industry professionals dedicated to being up-to-date on new technologies along with best practices. They are armed with the latest in diagnostic tools and are experienced in problem-solving that can achieve sustainable results. The TSG has walked in your shoes, and have felt your pain.