Key points
- Heat and humidity together accelerate every degradation mechanism
- Corona treatment decays far faster than most buyers expect
- Printed and metallised grades are more sensitive than plain film
- Rotating stock by date is simple, cheap insurance
Nobody has ever found film rotting in a warehouse. What does happen is a slow, cumulative loss of performance: treatment decay, hydrolysis in polyester, blocking in polypropylene, and edge damage that turns into a web break at full speed. Good storage practice is mostly about controlling the rate at which these processes run.
Temperature and humidity act together
Every degradation mechanism in packaging films is accelerated by heat and by moisture together. A roll stored for a week in a container at 40 degrees Celsius and 75 percent relative humidity is not the same product as one held at 22 degrees and 45 percent. If your warehouse cannot hold conditions, the practical answer is to keep the stock you will use soon in the coolest available space and to stagger deliveries so that a long dwell never accumulates.
Corona treatment decay
Surface treatment improves wetting and adhesion, but it is a surface phenomenon that reverts over time, faster at elevated temperature. Films stored for months may need re-treatment or may simply be unsuitable for the job they were treated for. This is one of the most common causes of a print adhesion complaint on material that was, in fact, perfectly good when it left the factory. Book inventory with a realistic window and verify treatment if material has been held a long time.
Polyester and hydrolysis
Polyester film is strong and dimensionally stable, but ester linkages are susceptible to hydrolysis in the presence of moisture at elevated temperature. For normal packaging conversions the effect is negligible; for material that will be stored for a long time or used in demanding conditions, it is worth specifying the storage environment rather than assuming. Polypropylene does not hydrolyse in this way, but it is more prone to blocking - layers sticking together - if the film is too warm or too heavily loaded.
Light, dirt and mechanical damage
Direct sunlight and ultraviolet exposure degrade surface appearance and, in clear films, cause yellowing over time. Dust and rolling debris create the small defects that become web breaks at speed. Handle reels on the flat face, never on the rim, and keep film off the floor. Edge damage is invisible on a core but fatal on a line, so a damaged edge should be trimmed before the reel goes back into production.
A simple stock rotation policy
Date every incoming reel, use first in first out, and review stock that has been held beyond your agreed window before it reaches a customer. Keep the innermost core label intact so the reel can always be identified. Most of these practices cost nothing beyond attention, and together they remove an entire category of avoidable customer complaints.
We ship with a documented storage recommendation for every grade and can advise on rotation policy for your own consumption profile. If your operation handles long project lead times or seasonal stock, talk to our technical team before the order rather than after the complaint.
Request samples or a quotation
Tell us the grade, thickness and quantity you need and our team will reply with a specification and lead time.