Record where the layers first resist separation
Begin with an observable description. Note whether PET layers resist separation while the roll is still stationary, during initial unwind, after staging near the line or only as the sheet enters feeding and heating. Avoid using one word—sticking—to describe every symptom.
Preserve the affected roll identity before changing anything. Record the roll or lot, sheet dimensions, first affected position and whether the condition is continuous or intermittent. This evidence is harder to recover after the roll has been rerun or moved.
Separate roll-layer sticking from machine symptoms
Layer blocking at the roll, feeding resistance, heating instability and sticking at mould or plug contact are separate observations. Watch the sheet through each stage and identify where normal movement first changes. If the problem begins after the web leaves the roll, do not assume the roll surface caused it.
Compare an affected roll with an unaffected reference where available. Keep the machine, mould and observation method controlled so that the difference can be traced.
Preserve storage and handling history
Record storage duration and conditions, wrapping status, stacking or orientation, movements, staging time and any visible roll damage. Do not invent universal storage or humidity limits; compare actual project history with the supplier's handling guidance and an unaffected reference.
Check whether the symptom follows a storage location, handling event, roll position or production interval. A controlled pattern is more useful than an unsupported conclusion.
Observe unwind without changing several variables
Document the unwind setup, web path and the point at which resistance appears. If an adjustment is safe and authorized, change one variable at a time and record the result. Multiple simultaneous changes can restore feeding without showing which condition mattered.
Avoid publishing one universal unwind setting. Roll dimensions, equipment and process requirements differ, so the usable setup must be confirmed on the actual line.
Use a simple evidence table
A short structured record helps the production team decide whether to retry the current sheet or request an anti-block comparison.
| Observation area | What to record | Decision supported |
|---|---|---|
| Roll | Identity, dimensions, affected position and visible condition | Whether the symptom follows specific material |
| Storage | Duration, location, wrapping, staging and handling history | Whether a repeatable handling pattern exists |
| Unwind | First resistance point, web path and feeding behaviour | Whether the issue begins before the machine process |
| Forming | Heating, sag, tool contact, definition and trimming | Whether the reported sticking begins later |
| Downstream | Printing, bonding or sealing observations | Whether a surface change remains compatible |
Decide whether to retry the current sheet
If the evidence points to an uncontrolled storage, staging, web-path or machine difference, stabilise that factor and retry under documented conditions before changing the sheet. Keep the comparison narrow and label the samples.
If the layer-separation problem remains repeatable and follows the material under controlled conditions, a surface-option trial may be justified.
Compare anti-block PET only after diagnosis
PUSITE can discuss silicone-oil-coated and embedded anti-block PET or R-PET options within a public starting range of 0.18–1.7 mm thickness and 250–1400 mm width, subject to confirming the project structure, gauge, width, colour and roll format. These options should be tested against the identified symptom, not treated as automatic cures.
Include the complete conversion route. Verify forming, appearance and any printing or bonding requirement, especially when an embedded anti-block option is considered.
Approve from a production-like trial
Run the current and proposed sheets under comparable conditions. Record layer separation, feeding, heating, forming definition, trimming and downstream results. Change one factor at a time so the outcome remains interpretable.
Document the approved sheet, roll presentation, process observations and unresolved verification points. Repeatable line stability matters more than a single easy unwind.
FAQ about PET roll sticking
These questions help distinguish a roll problem from a broader production issue.
Does unwind resistance prove the PET sheet is defective?
No. Preserve the roll evidence and compare storage, handling, unwind and machine conditions before assigning a cause. A repeatable controlled comparison is needed.
Should production change to anti-block PET immediately?
Only when the evidence supports a surface-related trial. First locate the symptom and stabilise obvious handling and process differences, then compare one surface option under production-like conditions.
What should be sent to the sheet supplier?
Send the roll identity, sheet dimensions, storage and handling history, photos or observations of the first sticking point, unwind behaviour, application, forming route and downstream printing or bonding needs.
Request a project-specific sticking review
Share where sticking first appears, roll identification, sheet dimensions, storage and handling history, unwind observations, the intended application and any printing or bonding steps. PUSITE can help organize the evidence and determine whether a controlled anti-block PET trial is appropriate.