The production of tear-resistant mailing bags requires refined operations in material selection, process optimization, structural design and inspection control. The following are specific steps and methods:
1. Material selection
The material is the key to determining the quality of tear-resistant mailing bags.
HDPE (high-density polyethylene): high toughness and puncture resistance, suitable for bags with high tear resistance requirements.
LLDPE (linear low-density polyethylene): good flexibility and tensile properties, increasing tear resistance.
Elastomer materials (such as EVA, TPU): enhance flexibility and impact resistance, reduce tearing risks.
Recycled materials and raw materials mixed: For environmentally friendly mailing bags, a certain proportion of high-quality recycled materials can be added to the formula, and ensure that it does not reduce the tear resistance of the bag.
2. Optimize processing technology
Processing technology directly affects the tear resistance of mailing bags:
Multi-layer co-extrusion technology: Combine the advantages of different materials through a multi-layer structure, such as outer layer tensile resistance and inner layer tear resistance.
Stretch orientation technology: Perform uniaxial or biaxial orientation treatment in film production to make the molecular chains more closely arranged and enhance the mechanical properties of the bag.
Thickness uniformity control: Ensure uniform film thickness through high-precision extrusion equipment to reduce the risk of tearing at weak points.
High-pressure molding process: Improve the density of the film and the neatness of the molecular chain arrangement, enhance its strength and durability.
Heat seal strength optimization: Ensure that the bag mouth sealing part has sufficient tear resistance by adjusting the heat seal temperature and pressure.
3. Structural design
The structural design of the mailing bag directly affects its tear resistance.
Thickening key parts: Local thickening design of the bag mouth, bottom or stress-prone parts to avoid tearing caused by concentrated pressure.
Double-layer edge seal design: Enhance the strength of the edge seal through double-layer heat sealing or multi-layer lamination.
Tear-resistant pattern design: Design concave and convex patterns on the surface of the bag to improve the tensile and tear resistance of the surface.
Zipper or adhesive tape improvement: Use high-strength zippers or adhesive seals to ensure that the seal is not easy to tear during transportation.
Aviation hole design: Add small vents to disperse the pressure inside the bag to prevent tearing due to excessive internal pressure.
4. Adding functional additives
Improve material properties through functional additives:
Tear-resistant enhancers: such as nanofibers or carbon fibers, improve the tear strength and ductility of materials.
Slip agents: reduce friction on the surface of the material to avoid tearing caused by friction damage.
Anti-aging additives: extend the service life of the bag and avoid aging leading to a decrease in tearing performance.
Barrier additives: improve the acid, alkali and moisture resistance of the material, and reduce tearing caused by chemical reactions during transportation.
5. Inspection and quality control
Tear strength test: use instruments to test the tear resistance of the film in the longitudinal and transverse directions.
Puncture strength test: verify the strength performance of the mailing bag when it is impacted by sharp objects.
Actual transportation simulation: simulate the packaging and transportation process to check the tear resistance of the bag under pressure, vibration and extrusion.
Heat seal strength test: ensure that the seal is not easy to tear during transportation and multiple openings.
A mailing bag with strong tear resistance requires multi-level technical cooperation.
