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Science Popularization Class on Toothless Zipper Bags

2025-07-26

Structure and Principle

The core of a toothless zipper bag lies in its non-toothed closing design, with common types including:

Concave-convex strip sealing type: The two sides of the bag opening are equipped with concave-convex strips that fit into each other, achieving sealing by manual squeezing or sliding block pushing, such as compression storage bags.
Magnetic closure type: It uses magnetic buckles or magnetic strips for adsorption and closure, and is often used in electronic products or high-end packaging.
Heat-sealing self-adhesive type: A sealing layer is formed by hot pressing or ultrasonic welding, such as food preservation bags.
Invisible zipper type: Nylon threads are interwoven with fabric, and metal sheets fix the zipper slider, featuring a hidden appearance as well as anti-slip and wear-resistant properties.

Materials and Characteristics

Polyethylene (PE)
Features: Resistant to low temperatures (-20℃) and has good waterproof performance, suitable for packaging frozen foods.
Applications: Fresh fruits, vegetables, and meat preservation, such as self-sealing bags.
Polypropylene (PP)
Features: Resistant to high temperatures (120℃) and strong oil resistance, can be heated in microwave ovens.
Applications: Snack packaging, hot food portioning.
Polyester (PET)
Features: High transparency, stretch resistance, and can withstand 150℃ for a short time.
Applications: Gift packaging, outer bags for medicines.
Ethylene-Vinyl Acetate Copolymer (EVA)
Features: Soft, UV-resistant, suitable for frequent opening and closing.
Applications: Cosmetics storage, travel toiletry bags.
Degradable Materials
Features: Corn-based or PLA materials, degradable in industrial composting environments, some have obtained BPI certification.
Applications: Environmentally friendly food packaging, disposable products.

Usage Scenarios and Advantages

Household Storage
Transparent bags make it easy to identify contents, are moisture-proof and dust-proof. Small items such as data cables and documents can be packed separately to avoid tangling.

Food Packaging
PE bags have strong moisture resistance, which can extend the shelf life of ingredients. Degradable bags are suitable for picnics or takeaways, reducing disposable waste.

Medical and Industrial Fields
Medical toothless zipper bags are sterilized with ethylene oxide and used for surgical instruments. Chemical-resistant materials (such as PET) can be used to package precision parts.

Travel
EVA material bags can hold wet swimsuits or toiletries, with leak-proof performance. Double-row toothless zipper bags can be manually deflated to save luggage space.

Science Popularization Class on Toothless Zipper Bags 1

Choosing a suitable toothless zipper bag and mastering the correct usage and maintenance methods can not only make item storage more organized and preservation longer-lasting, but also reduce the burden in daily life and contribute to the environment in details. This seemingly small design actually hides an accurate response to life's needs — using a simple structure to solve complex storage problems, making every opening and closing a manifestation of convenience and quality.