A controlled flexible-film specification should describe the complete packaging system, not only name one film. Buyers should define the layer sequence, nominal thickness or basis for tolerance, print side, barrier targets with test conditions, sealant function, converting format, filling process, product contact, storage and distribution conditions.
What belongs in the specification #
| Specification field | What to state | Why it matters |
|---|---|---|
| Structure | Layer order, material family and nominal gauge | Separates print, strength, barrier and seal functions |
| Barrier | Required OTR/WVTR and test conditions, when known | A value without temperature and humidity conditions is not directly comparable |
| Seal system | Sealant layer, filling temperature, seal geometry and machine conditions | The laminate must work on the actual filling and sealing route |
| Mechanical needs | Puncture, drop, flexing, zipper, spout or handle loads | These can change the layer choice and thickness |
| Compliance scope | Product, contact side, target market and required documents | Food-contact suitability applies to the finished intended use, not a material name alone |
Do not treat a common structure as a guaranteed result #
PET, BOPP, PE, CPP, PA, foil and metallized films can perform different functions, but the abbreviated structure name does not prove shelf life, seal strength, migration compliance or machinability. Resin grade, coating, adhesive, conversion quality, thickness, test conditions and the finished package all affect the result.
If a buyer has a shelf-life target, translate it into product risks and a validation plan. Use the flexible-packaging shelf-life validation guide to separate material screening from finished-pack testing. For broader selection logic, see the flexible films and laminates material selection guide.
Version control before production #
The approved specification should identify the revision, artwork, dimensions, construction, finish, seal details, roll direction or pouch format, inspection points and approved sample. A change to a layer, adhesive, gauge, supplier route or filling condition should trigger a documented review rather than being treated as an invisible substitution.
For rollstock, include equipment-interface data such as web width, repeat length, unwind direction, core, maximum roll dimensions and splice requirements. The rollstock specification guide for filling equipment explains those fields in detail.
Frequently Asked Questions #
Is a material name enough to specify a laminate? #
No. State the layer order, gauges or tolerances, print and seal sides, intended product, filling route and required performance.
Can OTR or WVTR be compared without test conditions? #
Not reliably. Confirm the test method, temperature, relative humidity, specimen construction and whether the value is for a film or finished package.
Does a high-barrier film guarantee the requested shelf life? #
No. Seals, package area, product sensitivity, storage, distribution and manufacturing variation also affect shelf-life performance.
When should a specification be reapproved? #
Reapproval is appropriate when the structure, supplier route, gauge, adhesive, coating, dimensions, artwork, filling conditions or other functional inputs change.
