A question we tend to receive is whether or not it is ok to use an adhesive that has passed its expiration date.
An adhesive can change over time. The effects of this ageing can go both ways. Either, the expired adhesive can be perfect for a certain application. When a new batch is ordered when it is time to start production, an entirely different result is obtained. In other cases, an adhesive that would be perfect could be overlooked just because the old one did not work.
An adhesive could stop curing at all, which would be easily spotted. But if it seems to work fine, it does not automatically become worse once expired. It is therefore not advisable to assume that a test with fresh adhesive will be better than with an old one. If you have performed preliminary tests with an expired product, make sure to verify the results with a fresh batch as well.
How do I know when the expiration date is?
The expiration date is normally printed on the bottle. Sometimes, the date can be coded in which occasion it can be easiest to ask us to check.
Of course, an adhesive does not expire on a specific day. But the expiration date is a good guideline to ensure that a good, and above all, repeatable result is achieved.
Keep in mind that the expiration date is based on an unopened package that has been stored and shipped under specified conditions. A cyanoacrylate should, for instance, be stored in a refrigerator for optimal shelf life. Other adhesives can require a freezer.
An opened package of adhesive is subject to moisture among other things which can reduce the shelf life. Therefore, it can be favourable to consider the packaging size. Perhaps a smaller package will be the most economic choice after all?
Guidelines for expired adhesive
In conclusion, the best way to avoid uneven results is to use adhesive products that have not passed their expiration date. If you notice when applying the adhesive, that something has changed, perhaps the appearance or cure speed of it, it is time to evaluate if it should be used in production. This could be the case even if the expiration date has not yet been passed.
To be sure, always check the date on the bottle. Also, make sure to store the adhesive according to its instructions!
Think of it like any perishable: If your food has passed the expiry date, it may well be okay – but if you end up with food poisoning, you can’t complain to the grocery store.
Contact us if you have any questions or if you need to order a fresh batch of material!