EVOH Co-Extruded Film vs. BOPA Film: A Strategic Comparison of High-Barrier Packaging Solutions
As demand grows across industries such as food, pharmaceuticals, and electronics for higher-performance packaging, two materials have emerged as leading high-barrier contenders: EVOH(ethylene-Vinyl Alcohol Copolymer) co-extruded films and BOPA (biaxially oriented polyamide) films. While both offer distinct advantages, their differences in barrier properties, mechanical strength, processing techniques, and sustainability make careful material selection essential.
1.Core Properties and Structural Advantages
1.1 Molecular Structure
Features hydroxyl (-OH) groups that form dense hydrogen bonding networks
Crystallinity reaches 60–70% (source: Kuraray XRD data)
This highly ordered structure significantly limits gas permeation
Example: Daikin used EVOH polymer to develop films with an oxygen transmission rate (OTR) of less than 0.01 cc/m²·day
BOPA
Contains amide (-NHCO-) groups that facilitate intermolecular hydrogen bonding
After biaxial orientation, crystallinity ranges from 30–40%
This improves strength but offers less barrier performance
Example: Toray achieved tensile strength exceeding 300 MPa through asynchronous orientation
1.2 Barrier Performance
EVOH
Follows the "solution–diffusion" model
OTR increases 1.5× for every 10°C rise (based on Arrhenius principles)
Example: EVOH films used by Zijiang to package salmon provided 100× better oxygen protection than standard BOPA at 4°C
BOPA
Relies on its dense structure but is highly sensitive to humidity
At 80% relative humidity, OTR increases by up to 10×
Solution: Amcor’s BOPA/PVDC laminate cut humidity-related permeability by 70%
2.Strategic Application Scenarios
2.1 Food Packaging: Material Selection by Function
When EVOH excels:
Fat-containing products: EVOH resin provides up to 100× better oil barrier
Case: Jinlongyu’s olive oil bottles use a PET/EVOH/PP structure, achieving a 24-month shelf life
Gas-filled packaging: Offers over 99% CO₂ retention (ASTM D1434)
Where BOPA leads:
Retort pouches: Resists up to 135°C for 40 minutes (GB/T 10004)
Case: Shuanghui uses BOPA-based packaging for sausages, with a rupture rate below 0.1%
Sharp-edge resistance: Puncture strength of 350 N/mm—5× that of EVOH
2.2 Medical Packaging: Compliance and Reliability
EVOH:
Stable under cobalt-60 irradiation up to 50 kGy
Case: Weigao Group uses EVOH co-extruded films for heart stent packaging, certified under FDA 510(k)
BOPA:
Compatible with ethylene oxide (EtO) sterilization
Case: Zhende Medical’s BOPA/PE surgical gowns reduced residual EtO and improved sterilization efficiency
3.Processing and Technical Considerations
3.1 Manufacturing Parameters
3.2 Modification Pathways
EVOH
Moisture Resistance: Mitsui developed silane-grafted EVOH that reduces moisture absorption by 50%
Example: Nongfu Spring used this in its 17.5° orange juice packaging, ensuring a 12-month shelf life even in humid climates
BOPA
Nano Reinforcement: Adding 5% nanoclay can reduce OTR by 40%
Example: Yongxin’s nano-BOPA film is now used in 5G component packaging
4.Sustainability and End-of-Life Impact
4.1 Recycling
EVOH:
Can be mechanically recycled with a post-processing retention rate over 90%
Case: Tetra Pak recycles EVOH/PE packaging with 95% efficiency
BOPA:
Requires chemical recycling; BASF’s ChemCycling process converts it to caprolactam
Case: Huafeng’s facility produces 50,000 tons of recycled PA6 annually
4.2 Carbon Footprint
Both Evoh Material and BOPA play key roles in high-performance packaging. EVOH plastic is unmatched in gas barrier performance, recyclability, and regulatory compliance, while BOPA provides mechanical strength and heat resistance where needed.
As a specialized EVOH supplier, we provide tailored co-extrusion solutions to help clients balance performance, cost, and sustainability. EVOH’s unique characteristics continue to redefine the possibilities of modern packaging—from shelf-life extension to environmental responsibility.