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PA PE coextruded food vacuum bag achieves molecular-level composite of nylon and polyethylene through multi-layer coextrusion process. Its structural characteristics are the synergistic effect of high barrier property of outer nylon and heat seal property of inner polyethylene. The interfacial fusion degree of this composite film directly affects the risk of chemical migration. The polar molecular structure of nylon layer and non-polar matrix of polyethylene form a physical barrier layer, which effectively inhibits the penetration and diffusion of low molecular weight substances.
The polyethylene layer on the side of PA PE coextruded food vacuum bag in contact with food uses food-grade resin raw materials. The residual amount of catalyst in the polymerization process is controlled by devolatilization process to avoid the precipitation of heavy metal ions. Coextrusion technology eliminates the hidden danger of solvent residue caused by the use of adhesives in traditional composite films, but precise control of processing temperature window is crucial to inhibit the generation of thermal oxidation byproducts.
In terms of temperature resistance, the high melting point characteristics of nylon layer on the other side of PA PE coextruded food vacuum bag provide structural support for high-temperature sterilization, and the change of crystallinity of polyethylene heat seal layer during heating process needs to ensure that no microcracks are generated. Under low temperature conditions, the material's ability to resist embrittlement depends on optimizing the co-extrusion interface stress distribution to prevent seal failure caused by delamination. Long-term storage tests have shown that the swelling effect of fat-soluble substances on the polyethylene layer can be suppressed by adjusting the comonomer ratio.
