Why EVA Laminated Glass Delaminates: Causes and Solutions

EVA laminated glass is widely used for decorative glass, architectural glazing, curved glass, smart glass, fabric-laminated glass, colored glass, and many other specialized applications.

When high-quality EVA film is combined with properly processed glass and the correct lamination parameters, the finished glass can provide excellent transparency, strong adhesion, moisture resistance, and long-term durability.

However, problems can occur when the glass, EVA film, silicone, vacuum system, or lamination process is not properly controlled.

One of the most common problems is EVA glass delamination.

Delamination can appear as edge bubbles, white areas, cloudy marks, trapped air, or separation between the EVA interlayer and the glass. Some defects appear immediately after lamination, while others become visible after several weeks or months of exposure to heat, moisture, sunlight, or installation chemicals.

To solve the problem correctly, the manufacturer must first identify the real cause. Increasing the oven temperature or reheating the glass without understanding the failure may only hide the problem temporarily.

What Is EVA Glass Delamination?

EVA glass delamination happens when the EVA interlayer loses full adhesion or contact with one or both glass surfaces.

The affected area may contain:

• Trapped air
• Moisture
• Gas
• Dust or contamination
• Chemical residue
• An incomplete adhesive bond
• A gap caused by distorted glass

Delamination may occur:

• Around the glass edges
• At the corners
• Around holes and cut-outs
• Near decorative inserts
• Around electrical connections in smart glass
• In isolated areas inside the laminate
• Across a large section of the glass

Small edge bubbles may initially look like only an aesthetic issue. However, if air or moisture continues to penetrate the laminate, the delamination can spread and affect the long-term performance of the glass.

Common Signs of EVA Glass Delamination

Different defects can indicate different causes. The location and appearance of the problem should always be carefully inspected.

Edge bubbles

Small bubbles or open areas appear around the perimeter of the glass.

Possible causes include:

• Poor vacuuming
• Incorrect silicone
• Low-quality tempered glass
• Mismatched glass edges
• Moisture penetration
• Glass contamination
• Excessive EVA movement during lamination

White or cloudy edges

A white or milky appearance may develop close to the edges.

Possible causes include:

• Moisture penetration
• Incompatible silicone
• Chemical migration from sealants
• Incomplete bonding
• Incorrect EVA film selection
• Poor edge protection

Random bubbles inside the glass

Bubbles may appear in the middle of the panel or in scattered areas.

Possible causes include:

• Trapped air
• Dust
• Wet glass
• Moisture inside decorative materials
• Insufficient vacuum time
• Heating too quickly
• Gas released from printed or decorative materials

Large transparent separation areas

A clear-looking gap may appear between the EVA and glass without a white or cloudy appearance.

Possible causes include:

• Weak adhesion
• Contaminated glass
• Insufficient curing
• Low lamination temperature
• Coated-glass incompatibility
• Poor glass contact

Bubbles around decorative inserts

Bubbles may appear near fabric, paper, wire mesh, printed films, natural materials, electrical connections, or PDLC smart film.

This usually happens because air or gas becomes trapped around the insert during lamination.

Main Causes of EVA Glass Delamination

1. Using the Wrong Silicone for Edge Sealing

Using an unsuitable silicone is one of the most important causes of EVA glass delamination.

Some silicone sealants contain oils, plasticizers, solvents, or other chemicals that may migrate into the EVA interlayer. These chemicals can gradually weaken the adhesion between the EVA and glass.

This may cause:

• White or cloudy edges
• Edge bubbles
• Softening of the EVA
• Loss of adhesion
• Chemical staining
• Progressive edge separation

A silicone may perform well for normal glazing but still be chemically incompatible with EVA interlayer film.

Based on Fuyin’s production experience, Toshiba silicone is the recommended silicone for sealing the edges of EVA laminated glass.

Alternative silicone brands should not be used unless their compatibility with the specific EVA film has been properly tested and confirmed.

Solution

Use Toshiba silicone for EVA laminated-glass edge sealing or perform a complete compatibility test before using any alternative product.

The silicone should be applied only after:

• The laminated glass has completely cooled
• The glass edges are clean
• The edges are dry
• Excess EVA has been properly trimmed
• The laminate has passed visual inspection

Never select silicone only according to price, color, or general glazing performance.

2. Low-Quality Tempered Glass and Mismatched Edges

Low-quality tempered glass is another major cause of EVA laminated-glass failure.

During tempering, poor temperature control, incorrect roller adjustment, unstable furnace settings, or weak production quality can cause the glass to become distorted.

Common tempered-glass defects include:

• Excessive bow
• Roller-wave distortion
• Edge lift
• Twisted glass
• Uneven corners
• Irregular shape
• Poor flatness

When two tempered-glass sheets are assembled, their edges should match closely.

If the edges do not match, a gap remains between the two sheets. The EVA film may temporarily fill part of this space during lamination, but if the gap is too large, proper bonding cannot be achieved.

Air and moisture may later penetrate through the open or weak edge area.

This can cause:

• Edge bubbles
• White edges
• Local separation
• Moisture penetration
• Progressive delamination

This problem is especially common when two tempered sheets have different or opposite bow directions.

Solution

Before lamination:

• Place the two tempered-glass sheets together
• Inspect all four edges
• Check whether the corners match
• Check for bow and edge lift
• Inspect the roller-wave direction
• Reject glass with excessive distortion
• Match the orientation of the two sheets where possible
• Use tempered glass from a reliable and controlled supplier

Good-quality EVA film cannot correct severely distorted tempered glass.

The quality and flatness of the glass are just as important as the quality of the interlayer.

3. The Glass Was Not Properly Cleaned

Glass cleanliness is one of the most important requirements for successful EVA lamination.

Even when glass appears clean, the surface may contain:

• Cutting oil
• Fingerprints
• Dust
• Silicone residue
• Detergent
• Protective-film adhesive
• Polishing compound
• Minerals from washing water
• Edge-grinding residue

These contaminants prevent the EVA from bonding properly with the glass.

The result may be immediate bubbles or delayed delamination after installation.

Solution

Wash the glass thoroughly using clean water. Demineralized water is preferred when available.

Make sure that:

• Washing-machine brushes are clean
• Water tanks are regularly maintained
• Filters are clean
• Air knives work properly
• The glass is completely dry
• Operators wear clean gloves
• Inner glass surfaces are not touched after washing

Special attention should be given to holes, corners, notches, and polished edges because water can remain trapped in these areas.

4. Moisture Was Trapped Inside the Laminate

EVA generally provides good resistance to moisture when correctly processed. However, moisture trapped during assembly can still create bubbles and cloudy areas.

Moisture may come from:

• Wet glass
• Condensation
• Humid production conditions
• Wet fabric or paper
• Natural decorative materials
• Water remaining after glass washing
• Improperly stored inserts
• Moisture inside printed materials

During heating, this moisture turns into vapor.

If the vacuum system cannot remove it, the vapor remains inside the laminate and creates defects.

Solution

Keep the production area clean and dry.

Before lamination:

• Make sure the glass is completely dry
• Store inserts in a dry environment
• Pre-dry absorbent materials when necessary
• Avoid assembling cold glass in a humid room
• Prevent condensation
• Keep EVA and inserts away from water

Materials such as paper, fabric, wood veneer, dried flowers, and natural leaves may require controlled pre-drying.

5. Insufficient Vacuuming

Vacuuming removes air from between the glass and EVA film before and during heating.

If the vacuum is weak, unstable, or applied for insufficient time, trapped air may remain inside the laminate.

Common vacuum problems include:

• A leaking silicone vacuum bag
• Damaged hoses
• Loose connectors
• A weak vacuum pump
• Poor sealing around the glass
• Incorrect breather placement
• A blocked vacuum channel
• Incorrect nozzle position
• Starting heating too early
• Stopping the vacuum too soon

Solution

Check the complete vacuum system before each production cycle.

The vacuum should remain stable during the critical heating and curing stages.

A vacuum reading at the pump does not always prove that air is being removed from every part of the panel.

Large glass panels, curved glass, thick constructions, and decorative laminates may require a longer pre-vacuum period.

The vacuum bag should be checked regularly for small leaks and damaged sealing areas.

6. Heating the Glass Too Quickly

If the oven temperature increases too quickly, the EVA at the edges may soften and seal before all the air has escaped.

The trapped air then expands as the temperature rises and forms bubbles.

Rapid heating is especially risky for:

• Thick glass
• Multiple EVA layers
• Large laminated panels
• Curved glass
• Decorative glass
• Smart glass
• Glass with holes or cut-outs
• Glass containing fabric or mesh

Solution

Use a controlled heating cycle.

The temperature should increase gradually so that:

• The EVA begins to soften
• The air can move toward the edges
• The vacuum system can remove the air
• The glass heats evenly
• The EVA cures properly

The correct heating cycle depends on:

• EVA formulation
• EVA thickness
• Glass thickness
• Glass size
• Oven design
• Number of panels
• Vacuum-bag arrangement
• Decorative materials
• Total oven load

Do not automatically use the same cycle for every EVA brand.

7. Insufficient Curing Temperature or Time

EVA film must receive enough heat and holding time to complete its curing or cross-linking process.

If the EVA is under-cured, it may look acceptable immediately after production but remain too soft or unstable.

Under-cured EVA may later develop:

• Edge movement
• Film displacement
• Loss of adhesion
• Bubbles
• Soft edges
• Delamination under heat
• Reduced outdoor durability

Solution

Confirm the actual temperature inside the glass laminate, not only the air temperature displayed on the oven controller.

Thick glass heats more slowly than thin glass.

A fully loaded oven may also require a longer cycle.

Use temperature sensors or test panels when necessary to confirm that the complete laminate reaches the required temperature and holding time.

Production parameters should be recorded for every batch.

8. Excessive Temperature or Overprocessing

Using excessive heat or an unnecessarily long cycle can also damage the laminate.

Possible problems include:

• Excessive EVA flow
• Edge thinning
• EVA movement
• Displacement of decorative inserts
• Color changes
• Damage to smart film
• Gas release from inserts
• Chemical reactions
• Distortion of sensitive materials

If too much EVA flows out from the edges, the interlayer may become too thin near the perimeter. These weak areas may later develop bubbles or separation.

Solution

Do not increase the temperature or heating time without technical justification.

Follow the recommended processing range for the specific EVA film.

Also avoid excessive pressure inside the vacuum bag, which may force too much EVA out from the edges.

9. Incorrect EVA Film Selection

Not every EVA film is suitable for every type of laminated glass.

Different EVA grades may be designed for:

• Indoor decorative glass
• Outdoor architectural glass
• Smart glass
• Colored laminated glass
• Fabric-laminated glass
• Acrylic lamination
• Polycarbonate lamination
• Low-temperature lamination
• Curved glass
• High-transparency applications

Using indoor-grade EVA for exterior glass may cause:

• Discoloration
• Loss of adhesion
• Edge failure
• Moisture-related defects
• Reduced UV resistance
• Delamination

Solution

Select the EVA film according to the final application, not only according to thickness or price.

Before ordering, provide the supplier with:

• Indoor or outdoor application
• Glass size
• Glass thickness
• Flat or curved construction
• Glass type
• Coated or printed surface
• Type of decorative insert
• Expected temperature exposure
• Required clarity
• Required durability
• Smart-film requirements

Fuyin supplies different grades of EVA interlayer film for laminated glass for clear, decorative, colored, curved, smart, and architectural applications.

10. Incorrect EVA Film Storage

Improper storage can affect the cleanliness, flatness, and performance of EVA film.

Problems may occur when EVA rolls are:

• Stored in direct sunlight
• Exposed to high temperatures
• Left uncovered
• Stored in dusty areas
• Placed directly on the floor
• Stored near solvents or chemicals
• Stored in a deformed position
• Contaminated during handling

Solution

Keep EVA film:

• In its original packaging
• In a clean environment
• In a dry area
• Away from direct sunlight
• Away from heat sources
• Away from dust
• Away from chemicals

After opening the roll, protect the remaining film from contamination and follow the supplier’s storage instructions.

11. Air Trapped Around Holes, Cut-Outs, and Complex Shapes

Holes, notches, sharp corners, and irregular shapes can block the movement of air toward the edges.

Air may remain trapped around these areas even when the vacuum pump appears to be working correctly.

Solution

Use appropriate breather materials and vacuum channels around:

• Holes
• Notches
• Cut-outs
• Electrical connections
• Decorative inserts
• Irregular shapes

Increase the pre-vacuum time for complex panels.

Check whether the vacuum bag makes uniform contact with the entire glass surface.

12. Incompatible Inks, Coatings, Tapes, or Decorative Materials

EVA may come into contact with:

• Ceramic ink
• Digital printing
• Paint
• Mirror backing
• Low-E coatings
• Adhesive tape
• Decorative film
• Fabric
• Paper
• Wire mesh
• Natural materials
• PDLC smart film

Some materials may release oils, plasticizers, solvents, gases, or other chemicals during heating.

These substances can interfere with adhesion and cause:

• Bubbles
• Discoloration
• White marks
• Softening
• Edge separation
• Delamination

Solution

Never assume that two materials are compatible simply because they work well separately.

Before mass production:

1. Produce a sample using the actual materials.
2. Use the actual glass, EVA, ink, coating, silicone, tape, and insert.
3. Laminate the sample using the planned production cycle.
4. Test the sample under heat and humidity.
5. Inspect it for bubbles, color changes, softening, and separation.
6. Obtain technical confirmation from suppliers where possible.

13. Poor Edge Protection or Incorrect Installation

A properly manufactured EVA laminated panel can still fail if it is installed incorrectly.

Installation-related problems include:

• Standing water around the edges
• Blocked drainage channels
• Incorrect silicone
• Incompatible gaskets
• Aggressive cleaning chemicals
• Exposed laminate edges
• Poorly designed frames
• Incorrect setting blocks
• Excessive pressure on the glass edge

Solution

The glazing system should allow water to drain freely.

The installer should:

• Use compatible silicone
• Protect exposed edges
• Use suitable gaskets
• Avoid aggressive chemicals
• Prevent continuous water contact
• Avoid excessive edge pressure
• Follow the glass manufacturer’s installation instructions

How to Diagnose EVA Glass Delamination

The time and location of the defect can help identify the possible cause.

Defects visible immediately after lamination

Likely causes include:

• Weak vacuum
• Wet glass
• Contaminated glass
• Heating too quickly
• Insufficient curing
• Poor glass contact
• Distorted tempered glass
• Trapped air around inserts

Defects appearing after several days

Likely causes include:

• Incomplete curing
• Residual moisture
• Weak adhesion
• Internal stress
• Gas released from decorative materials
• Early exposure to high temperature

Defects appearing after several months

Likely causes include:

• Wrong silicone
• Chemical incompatibility
• Low-quality tempered glass
• Poor edge protection
• Water penetration
• Incorrect EVA grade
• Long-term heat exposure
• Progressive adhesion loss

The First Three Checks for Edge Delamination

When bubbles or separation appear around the glass edges, the processor should first check:

1. Whether Toshiba silicone or another confirmed compatible silicone was used
2. Whether the tempered-glass edges matched correctly
3. Whether the vacuum process was stable and sufficient

These three checks can identify many common edge-delamination problems before changing the lamination temperature or blaming the EVA film.

Can Delaminated EVA Glass Be Repaired?

Some small bubbles caused by incomplete processing may be reduced by repeating part of the vacuum and heating cycle.

However, successful repair is not guaranteed.

Reprocessing will not reliably solve defects caused by:

• Contaminated glass
• Incorrect silicone
• Chemical incompatibility
• Severely distorted tempered glass
• Water penetration
• Damaged edges
• Wrong EVA film
• Degraded EVA
• Poor installation

For architectural or safety applications, the panel should be carefully evaluated before reuse.

In many cases, replacement is safer and more economical than attempting to repair a laminate with an unknown failure cause.

EVA Lamination Prevention Checklist

Before starting production, confirm the following:

• The correct EVA grade has been selected.
• The EVA film has been stored correctly.
• The glass is clean.
• The glass is completely dry.
• Operators are wearing clean gloves.
• The tempered-glass edges match correctly.
• The glass does not have excessive bow or edge lift.
• Decorative inserts are dry.
• All inserts are compatible with EVA.
• The vacuum bag does not leak.
• Vacuum hoses and connectors are in good condition.
• A stable vacuum is achieved before heating.
• The heating rate is controlled.
• The laminate reaches the required temperature.
• The holding time is sufficient.
• The vacuum remains active during the required stages.
• The glass is cooled correctly.
• Toshiba silicone or another tested compatible silicone is used.
• The edges are protected from water.
• Production parameters are recorded.

Frequently Asked Questions

Why does EVA laminated glass develop bubbles around the edges?

The most common reasons are incorrect silicone, poor vacuuming, moisture penetration, low-quality tempered glass, mismatched edges, excessive EVA flow, and insufficient curing.

Which silicone should be used for EVA laminated glass?

Based on Fuyin’s production experience, Toshiba silicone is recommended for sealing EVA laminated-glass edges. Alternative products should only be used after compatibility with the EVA film has been tested and confirmed.

Can low-quality tempered glass cause EVA delamination?

Yes. If tempered glass has excessive bow, roller wave, edge lift, or twisted edges, the two glass sheets may not match correctly. Air and moisture can then penetrate through the weak edge area.

Why do the glass edges need to match?

The edges must remain close together so the EVA can create a complete and continuous bond. If a large gap remains, the edge may not seal properly, increasing the risk of air and moisture penetration.

Is EVA completely resistant to moisture?

Properly processed EVA provides good moisture resistance. However, wet glass, standing water, exposed edges, incorrect silicone, and poor installation can still cause delamination.

Can the same oven settings be used for every EVA brand?

No. Different EVA formulations may require different heating, vacuuming, curing, and cooling parameters.

Why is the EVA still soft after lamination?

The laminate may not have reached the correct curing temperature, or the holding time may have been too short.

Does thicker EVA prevent delamination?

Thicker EVA may help fill small gaps or accommodate decorative inserts, but it cannot correct contaminated glass, poor vacuuming, incompatible silicone, severely distorted glass, or incorrect curing.

Conclusion

EVA glass delamination is usually caused by a combination of material, glass, processing, and installation problems.

The most important causes include:

• Using the wrong silicone
• Low-quality tempered glass
• Mismatched glass edges
• Poor glass cleaning
• Trapped moisture
• Insufficient vacuuming
• Incorrect heating
• Incomplete curing
• Incompatible materials
• Poor edge protection

For edge-related failures, silicone compatibility and tempered-glass quality should always be checked before blaming the EVA interlayer.

Good-quality EVA film cannot compensate for distorted glass, contaminated surfaces, weak vacuuming, or incompatible silicone.

The most effective way to prevent delamination is to control every stage of the process, from film selection and glass preparation to vacuuming, heating, cooling, silicone application, and final installation.

Fuyin supplies professional EVA interlayer film for clear, colored, decorative, curved, smart, and architectural laminated-glass applications.

Our technical team can help customers select the correct EVA grade and establish suitable lamination parameters according to their glass construction and equipment.

Need EVA film or technical support for laminated-glass production?

Contact Fuyin Group to discuss your glass composition, EVA thickness, lamination equipment, and production requirements.