Oct 3, 2026Mylar Bags
Why Do Mylar Bags Delaminate When Opening? Causes & Solutions
Mylar bag layers peeling or separating when opened? Learn what causes delamination and uneven tearing, and how material and tear scoring can improve the opening experience.
Why Do Mylar Bags Delaminate When Opening? Causes & Solutions
Your custom Mylar bag looks great — until someone tries to open it.
The tear strip is difficult to pull. The film separates. Or part of the printed layer peels away with the top of the bag.
This is a packaging issue we've recently been asked about by a customer looking for a new supplier for custom child resistant Mylar bags.
So, what causes it — and how can it be improved?
What Causes Mylar Bags to Peel When Opening?
Mylar bags are typically made from multiple laminated film layers.
When these layers, the tear structure, and the opening design don't work well together, you may see:
- Film layers separating during opening
- Printed artwork peeling near the tear area
- An uneven or rough tear
- Excessive force required to open the bag
- The tear running in the wrong direction
The problem is not always caused by one factor.
Here are several areas we normally check.
1. Lamination Strength
If the laminated films are not bonded properly, pulling the tear strip may separate the layers instead of allowing them to tear together cleanly.
This can become especially noticeable around the top opening area.
The material structure, adhesive, curing and production process all need to work together.
2. Tear Notch and Scoring
The tear notch tells the consumer where to start opening the pouch.
For some bag structures, additional scoring can help control how the tear travels across the package.
But scoring that is too deep, too shallow or inconsistent can create another problem rather than solve one.
The goal is a clean and controlled tear without damaging the printed layers.
3. Material Structure
Not every laminated structure behaves the same way when torn.
This becomes more important when your custom pouch combines features such as:
- Child-resistant zipper
- Holographic film
- Matte finish
- Glossy elements
- Metallic effects
- Hang holes
- Custom printed areas
The bag shouldn't only look good. Its material structure also needs to work with the opening method.
A Real Packaging Problem We Were Asked to Solve
Recently, a customer approached us while evaluating a new supplier for their custom Mylar bags.
Their existing pouch included a child-resistant resealable zipper, tear-open top, hang hole and a combination of holographic, glossy, matte and printed elements.
Their main concern wasn't the artwork.
When opening the tear strip, parts of the laminated or printed layer could peel or separate, making the bag difficult to open cleanly.
Instead of immediately recommending a new bag structure, we asked the customer to send us a short video showing exactly how the pouch fails during opening.
This is important because different failure patterns can point to different causes.
How We Troubleshoot the Problem
When a customer has an existing bag with an opening problem, we normally review:
1. Where does the tear begin?
Does it start correctly from the tear notch?
2. Where does the separation happen?
Is the whole laminate separating or only one surface layer?
3. How much force is required?
A bag shouldn't require excessive force before the tear begins.
4. Does the tear travel cleanly?
The opening should follow the intended path instead of running into the printed area.
5. What is the existing film structure?
Material construction can significantly affect tear performance.
Once we understand the failure, we can evaluate whether adjustments are needed to the lamination, material structure, tear notch or scoring.
Don't Test Only the Appearance
A digital mockup can show you how your artwork will look.
It cannot tell you how the finished pouch will actually open.
For custom child resistant Mylar bags, we recommend checking both appearance and function before mass production.
That includes the CR zipper, tear opening, sealing, material structure and printed finish.
Having the Same Problem With Your Mylar Bags?
If your current bags are difficult to open, tear unevenly or experience layer separation around the tear strip, you don't have to start from scratch.
Send us:
- A short video showing the opening problem
- Bag dimensions
- Artwork or dieline
- Required quantity
- Finish requirements
- Your current material structure, if available
Our team can review the issue and recommend possible improvements for your next production run.
We manufacture custom child resistant Mylar bags with CR zippers, custom sizes, hang holes, tear-open designs and matte, glossy, holographic and other custom finishes.
Have a packaging problem you're trying to solve? Send it to us and we'll take a look.
