VMPET vs AL/PE Duct Facing: A Practical Selection Guide for Duct Manufacturers

The outer facing material of flexible ventilation ducts directly determines the product's weather resistance, thermal insulation, and service life. For purchasing managers at duct manufacturing plants, choosing between metallized film VMPET and aluminum foil PE composite materials often leads to confusion—the two may look similar, but perform quite differently. This article examines material structure, performance differences, and selection recommendations to help buyers make informed decisions.

1. Structural Differences Between the Two Materials

VMPET duct facing uses polyester film (PET) as the base substrate, with an aluminum layer deposited via vacuum metallization, then laminated with a PE layer. The structure is VMPET/PE, with an aluminum layer thickness typically in the range of 30-50 nanometers, and overall thickness of approximately 0.05-0.12 mm.

AL/PE duct wrap uses pure aluminum foil as the base material, with aluminum layer thickness of 6μm-9μm (heavy grade 9μm), bonded to a PE layer through dry lamination or extrusion coating. The common structure is AL/PE, with overall thickness of approximately 0.07-0.15 mm. Some premium products use double-sided structures such as AL/PE/AL or AL/PE/PET/AL to enhance barrier properties and mechanical strength.

Structurally, the aluminum layer in AL/PE composite is hundreds of times thicker than that in VMPET. This fundamental difference determines the gap in barrier performance and mechanical strength between the two materials.

2. Core Performance Comparison

Barrier Properties: AL/PE composite typically achieves oxygen transmission rate (OTR) below 0.1 cm³/(m²·24h·0.1MPa) and water vapor transmission rate (WVTR) below 0.5 g/(m²·24h), making it suitable for applications with strict moisture-proof requirements. VMPET achieves OTR of approximately 1-5 cm³/(m²·24h·0.1MPa) and WVTR of approximately 1-3 g/(m²·24h)—about one-tenth the barrier performance of aluminum foil, but sufficient for general ventilation applications.

Temperature Resistance: AL/PE composite typically supports long-term use at 80-100°C and short-term exposure up to 120°C. VMPET has a slightly lower temperature range, with long-term use at 60-80°C and short-term exposure up to approximately 100°C. For high-temperature applications such as kitchen exhaust, AL/PE composite holds a clear advantage.

Mechanical Strength and Flex Resistance: AL/PE composite offers higher tensile strength, but pure aluminum foil tends to develop pinholes and cracks after repeated bending, compromising barrier performance. The PET substrate in VMPET provides excellent flex resistance and puncture resistance, performing better in applications requiring frequent bending or vibration.

Cost Difference: VMPET raw material costs are typically 20%-40% lower than AL/PE composite, offering significant cost advantages for high-volume, low-margin ventilation duct products.

Surface Finish and Appearance: VMPET duct facing generally delivers a brighter, more reflective metallic appearance due to the smooth PET substrate surface. AL/PE composite may show slight surface texture from the aluminum foil rolling process, though both matte and glossy finishes can be achieved through calendering or coating processes. For applications where visual appearance matters, such as exposed ductwork in commercial spaces, surface finish should be specified during procurement.

3. Selection Recommendations by Application

Central Air Conditioning Supply/Return Air Systems: Moderate barrier requirements and cost sensitivity make VMPET duct facing the recommended choice. Its cost advantage and adequate weather resistance satisfy the needs of most commercial and residential buildings.

Kitchen Exhaust/High-Temperature Ventilation: Oil mist contains grease and high-temperature steam, demanding oil resistance and temperature tolerance. AL/PE duct wrap is recommended, especially heavy-grade products with 9μm aluminum layer thickness, for assured temperature resistance and barrier performance.

Fresh Air/Ventilation Systems: These applications demand high flex resistance and long service life, with ducts subject to frequent bending and vibration. VMPET duct facing is recommended due to its superior flex resistance and fatigue performance compared to AL/PE composite.

Industrial Exhaust/Corrosive Gas: Applications requiring extreme chemical stability and barrier performance call for double-sided aluminum foil composite or thickened AL/PE structures with 9μm aluminum layer thickness, paired with chemically resistant PE grades.

4. Key Purchasing Verification Points

Regardless of material choice, buyers should focus on three critical verification steps:

First, verify aluminum layer thickness. AL/PE composite requires 6μm-9μm aluminum layer thickness, measurable with a micrometer and cross-checked against grammage. For VMPET, buyers should assess aluminum layer uniformity and optical density, using a multimeter to measure surface resistance as a supplementary check.

Second, test lamination strength. Peel strength is the key indicator of composite quality; AL/PE structures should achieve ≥1.5N/15mm. A simple on-site tear test can be performed: tear along the composite edge—if separation between the aluminum layer and PE is difficult and the tear surface is uniform, lamination strength is acceptable.

Third, confirm slitting quality. Duct facing materials are typically slit to specific widths, and edge burr and slitting precision directly affect downstream duct forming efficiency. Request slitting precision reports from suppliers, with width tolerance controlled within ±1mm.

Hangzhou Hongcheng Technology Co., Ltd. has extensive experience in aluminum foil composite materials, operating multiple dry lamination and extrusion coating production lines. We offer VMPET duct facing, AL/PE duct wrap, and single-sided/double-sided aluminum foil composite films in various specifications. Aluminum layer thickness ranges from 6μm-9μm (heavy grade 9μm), with customizable widths from 200mm to 1600mm and PE layer thicknesses from 15μm to 60μm. Both matte and glossy surface finishes are available. Our products comply with RoHS environmental standards and are exported to Europe, North America, the Middle East, and Southeast Asia. Duct manufacturers and flexible duct producers are welcome to inquire about samples and quotations.

+86 13758223270 Email: wendy@hcdxcl.com.cn