Many people may want to know which barrier structure is better for fresh food?and how to choose them ? Here are some frequently asked questions and answers regarding the choice between EVOH-based and PA/PE-based films for fresh food packaging,we hope can help you.
Q1: What is the fundamental difference between EVOH and PA/PE films for fresh food packaging?
A:
EVOH (Ethylene Vinyl Alcohol) film is the gold standard for oxygen barrier, offering the lowest oxygen transmission rate (OTR) among clear polymers. It is the material of choice when the goal is to maximize shelf life by aggressively blocking oxygen.
PA/PE (Polyamide/Polyethylene) film, also known as nylon/PE, offers a balanced solution. While its oxygen barrier is significantly lower than EVOH's, it compensates with exceptional mechanical strength-high puncture resistance, tear strength, and impact resistance-making it ideal for durable, rugged packaging.
Q2: What is the single biggest weakness of EVOH, and how does PA/PE compare?
A: The major limitation of EVOH is its moisture sensitivity. As relative humidity increases, its oxygen barrier properties degrade significantly. This means that in high-moisture environments-like inside a package containing fresh meat or produce.
PA/PE, in contrast, is much less sensitive to humidity. It provides a more stable, predictable barrier.
Q3: Can EVOH and PA be used together in one film structure?
A: Yes, and this is the industry's preferred solution for high-performance packaging. Modern multi-layer coextrusion technology allows films with structures like: PE / Tie Layer / PA / EVOH / PA / Tie Layer / PE
In this structure.
Q4: How should I choose between EVOH and PA/PE for my specific application?
A: general rule of thumb: Choose EVOH for maximum barrier when conditions are dry. Choose PA/PE for balanced performance and durability when conditions are challenging or physical risks are high. Choose both (EVOH+PA) for premium, all-around performance. More details as below:
|
Consideration |
EVOH Film |
PA/PE Film |
|
Oxygen Sensitivity |
High. Product easily oxidizes (e.g., nuts, ground coffee). |
Moderate. Product can tolerate some oxygen. |
|
Storage/Use Humidity |
Low humidity environment. The film can be kept dry. |
High humidity (e.g., refrigerated, fresh meat with high drip loss). |
|
Physical Risk |
Low. Product is smooth and handling is gentle. |
High. Product has sharp edges or undergoes rough transport. |
|
Target Shelf Life |
Long (e.g., > 6 months). |
Shorter to moderate (e.g., 1–3 months). |
Send your product, packaging machine and shelf-life requirement. Fuya can recommend a suitable multilayer film structure.
