Encountering an odor when opening sealing film is a problem many users have faced. Some worry it indicates unsafe materials, while others suspect production contamination. In fact, there are multiple possible causes for sealing film odor, each requiring individual investigation. Today, Leadtra Packaging will help you analyze common causes and solutions.

1. Where Does the Odor Come From? Look at These Main Areas

Odor in sealing film is usually not from a single source but results from multiple factors combined across raw materials, processes, and storage.

Odor from raw materials themselves: Materials commonly used in sealing film — PE, PET, aluminum foil, adhesives — have their own inherent "raw material smell." PE and other plastic materials, in particular, release small amounts of low-molecular-weight substances during processing, producing a "plastic-like" odor. Higher-quality raw materials have a lighter smell that dissipates over time.

Residual printing ink or solvents: When using custom-printed sealing film, if the ink or thinner hasn‘t fully evaporated, residual solvents can create a pungent odor. This is one of the main causes of odor in printed sealing film.

Odor from adhesives or heat-seal layers: The adhesives used in producing laminated films, or the heat-seal layer materials themselves, may release trace odors when exposed to high temperatures. Unstable-quality adhesives are more prone to producing odors.

Influence of storage environment: If sealing film is stored in high-temperature, high-humidity, or poorly ventilated environments, it can easily absorb ambient odors or undergo accelerated aging that produces smells.

2. How to Judge Whether the Odor Is Normal?

Not all odors indicate a defective product. Use these guidelines:

Slight raw material smell: A faint smell upon opening the package that dissipates after airing for a while is normal.

Pungent, chemical smell: A strong, irritating odor that lingers suggests possible solvent residue or material abnormality.

Rancid or musty smell: Indicates a humid storage environment or moisture intrusion due to damaged packaging.

3. How to Solve Sealing Film Odor Problems?

Choose high-quality raw materials: Select low-odor, low-residue PE and PET substrates, and use solvent-free lamination processes to reduce odor generation at the source.

Optimize printing processes: Ensure ink and solvents are fully dried, control post-print curing time, and use solvent-free inks when necessary.

Control storage environment: Store sealing film in a cool, dry, well-ventilated area, away from direct sunlight, high temperature, and high humidity. Seal opened packages promptly to minimize absorption of ambient odors.

Aerate before use: If the odor is mild, spread the sealing film out in a ventilated area for a few hours; the smell will usually diminish significantly.

4. Recommendations for Purchasers

When procuring sealing film, you can reduce the risk of odor by:

Requiring suppliers to provide certification of low-odor or low-VOC (volatile organic compound) materials

Specifying the use of solvent-free inks and adequate curing time for custom-printed orders

Conducting odor sampling inspections upon receipt, establishing incoming inspection standards

Performing small-batch testing before full-scale use to confirm no odor issues

5. Leadtra Packaging‘s Quality Control Measures

Leadtra Packaging implements strict control procedures for sealing film odor:

Odor testing of raw materials before they enter the factory

Control of temperature, humidity, and timing parameters during lamination, curing, slitting, and other production processes

Sampling and odor inspection before finished products leave the factory, ensuring only odor-free batches are released

Offering low-odor, low-VOC customization options for export clients

Conclusion

An odor in sealing film doesn‘t necessarily mean the product is substandard, but it does merit attention. From raw materials to processes to storage, every step can affect the final odor profile. Once the cause is identified, targeted adjustments can resolve the issue.

Leadtra Packaging offers low-odor sealing film customization services. You are welcome to send samples or provide specific requirements, and we will match you with the most suitable solution.