Surlyn Film: High-Performance Ionic Polymer Films
Surlyn Film is a specialty film made from ethylene-methacrylic acid ionomer resin. Its core material-Surlyn resin-is produced by DuPont using a unique process. Based on an ethylene-methacrylic acid copolymer, it is partially or fully neutralized with metal ions such as sodium, potassium, magnesium, or zinc to form a thermoplastic resin with an ionically cross-linked structure.
This ionic cross-linked structure gives Surlyn Film unique properties that distinguish it from ordinary polyethylene film: the ionic cross-links between molecular chains provide excellent strength and toughness at room temperature, while the ionic bonds reversibly dissociate when heated, allowing the material to be processed and molded like ordinary thermoplastics. It is precisely this "thermally reversible cross-linking" characteristic that allows Surlyn Film to combine the convenience of thermoplastic processing with mechanical properties approaching those of thermosetting materials.
Core Performance Advantages of Surlyn Film
Exceptional Optical Transparency
Surlyn Film is hailed as "transparent polyethylene," with transparency far exceeding that of ordinary PE film. Its ionic cross-linking structure suppresses the crystallization behavior of polyethylene, enabling the material to maintain high light transmittance while exhibiting low haze; some grades have haze as low as 2.0% and gloss levels exceeding 85%. This characteristic makes the products inside the packaging clearly visible, helping to enhance visual appeal on the shelf.
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Superior Sealing Performance
In terms of heat-seal strength, Surlyn Film features an extremely low initial sealing temperature, a wide heat-seal window, and outstanding heat-seal adhesion. It achieves reliable seals even when moisture, grease, or dust residues are present in the sealing area. This "contaminant-sealing" property significantly reduces leakage rates when packaging fresh products containing liquids. On high-speed packaging lines, its superior heat-seal strength supports faster production speeds, with efficiency improvements of up to 300% in certain applications.
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Outstanding Toughness and Puncture Resistance
Surlyn Film offers excellent low-temperature impact toughness, puncture resistance, and abrasion resistance. It maintains good flexibility even in sub-zero temperatures and is not prone to brittle fracture, making it particularly suitable for frozen food packaging and cold-chain logistics. Some grades achieve a drop-weight impact strength of over 700 grams, with puncture resistance superior to that of comparable competitors.
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Oil and Chemical Resistance
Surlyn Film exhibits outstanding resistance to oils, solvents, and chemicals. It does not degrade or fail to seal when in contact with oil-containing foods, making it suitable for packaging high-fat products such as meat and cheese.
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Excellent Formability
In vacuum skin packaging processes, Surlyn Film can be deeply stretched after heating to closely conform to the product's complex contours. Combined with its high transparency, it creates a "second-skin" effect, making it particularly suitable for packaging bone-in meats and irregularly shaped products.
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