Beyond Standard Metallized PET: Ultra‑High Barrier, Enhanced Adhesion, and Ultra‑Thin Aluminum Layer Films Explained

Ultra‑High Barrier Metallized PET, Enhanced Adhesion, and Ultra‑Thin Aluminum Layer Films

2026.07.08

Defining Barrier Levels for Metallized PET

Not all metallized PET films deliver the same barrier performance. Based on Cailong's classification:

Category	OTR & WVTR (cc or g/m²·24h)	Typical Use
Ultra‑high barrier	≤0.5	Long‑shelf‑life food, pharmaceuticals
High barrier	≤1	Premium snacks, dry goods
Standard high barrier	≤2	General packaging

Cailong states that all their metallized products can achieve OTR and WVTR ≤0.5, placing them in the ultra‑high barrier tier. This is achieved through precise vacuum deposition process control and high‑quality base films.

ScreenShot_2026-07-07_095445_914

Enhanced Adhesion Metallized PET Film

Standard metallized PET may suffer from poor aluminum adhesion when exposed to moisture, oil, or aggressive food contents. Enhanced adhesion grades solve this by using a specially primed (bottom‑coated) base film before metallization.

Three sub‑grades are available:

Grade	Processing Capability
Standard enhanced	General high‑adhesion
Boil‑proof enhanced	Withstands boiling water immersion
Retortable enhanced	Survives high‑temperature retort (depends on process and structure)

Target applications:

Coffee bags (oil migration resistance)
Sauce and seasoning sachets (liquid contact)
Cooked meat / ready‑to‑eat food pouches
Daily chemical packaging (detergent refills)
Pharmaceutical blister lidding

Note: adhesion performance varies depending on the metallization equipment used, even with the same base film. Cailong's proprietary process ensures consistent results.

BOPP-AlOx-GZ结构图

Ultra‑Thin Aluminum Layer PET Film (40 Å)

Conventional metallized PET has an aluminum layer thickness typically around 300–500 Å (ångströms). Reducing thickness below 100 Å while maintaining uniformity is technically challenging because uneven deposition causes color variation and inconsistent shading/thermal insulation.

Cailong has innovated to produce aluminum layers as thin as 40 Å with a thickness tolerance of ±3% across the web.

Why ultra‑thin matters:

Color consistency – no streaks or patches in window film
Thermal insulation – uniform IR rejection for architectural/automotive film
Shading effect – predictable light transmission
Material savings – less aluminum used per square meter

Applications:

Automotive window film (sun control, privacy)
Building window film (energy efficiency)
High‑end electronics (EMI shielding, decorative trim)

Comparison Table: Three Specialized Products

Feature	Ultra‑High Barrier MPET	Enhanced Adhesion MPET	Ultra‑Thin Al Layer MPET
Barrier level	OTR/WVTR ≤0.5	Depends on base film; ≤0.5 achievable	Not primary focus
Key selling point	Extreme shelf life	Oil/water/retort resistance	40 Å thickness, ±3% uniformity
Main industries	Food, pharma	Wet food, coffee, sauce, chemicals	Automotive, construction, electronics
Typical thickness range	12–23 µm	12–23 µm	12–50 µm

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FAQ (SEO Snippet Target)

Q: What is considered ultra‑high barrier for metallized PET?

A: OTR and WVTR both ≤0.5 cc or g/m²·24h is defined as ultra‑high barrier.

Q: Can enhanced adhesion metallized PET be retorted?

A: Yes, the retortable enhanced grade can withstand high‑temperature retort processing, though final performance depends on the lamination structure and sealing method.

Q: How thin can the aluminum layer be on PET film?

A: Cailong achieves 40 Å (ångströms) with ±3% uniformity, which is among the thinnest commercially available metallized layers.

Q: What is the advantage of 40 Å aluminum layer for window film?

A: It provides uniform color, consistent IR/UV rejection, and minimal visual distortion, while using significantly less aluminum than conventional films.

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