The Journey of an Airtight Zipper

Here at LEOT, we believe that the best gear is built on reliable, often unseen, components. The zipper on your waterproof jacket, heavy-duty storage bag, or protective cover isn’t just a fastener—it’s a critical seal. But how does a simple coil of yarn become a robust, airtight zipper?

This is the story of that journey. It’s a process built on precision, rigorous testing, and an unwavering commitment to quality. Let’s pull back the curtain and follow the path from raw material to the finished LEOT airtight zipper you can trust.

Step 1: Sourcing the Core – Premium Raw Materials

Every great product starts with great ingredients. For our airtight zippers, this means:

• High-Tenacity Nylon Yarn: We source exceptionally strong and durable nylon. This forms the “skeleton” of the zipper tape, providing the foundational strength and flexibility needed to withstand stress and repeated use.
• Precision-Molded Sliders and Elements: The zipper teeth (or elements) and slider are typically engineered from materials like Polyoxymethylene (POM). We choose POM for its low friction, high dimensional stability, and excellent resistance to wear and chemicals, ensuring a smooth, long-lasting glide.
• Specialized Coating Compounds: The key to “airtight” lies here. We use advanced polymer coatings, such as thermoplastic polyurethane (TPU), which are meticulously formulated to create a perfect, seamless seal once applied and fused.

Our Commitment: We never compromise on material quality. It’s the first and most crucial step in delivering the performance we promise.

Step 2: Weaving the Foundation – Creating the Zipper Tape

The strong nylon yarn is woven into a sturdy, dense tape on high-speed looms. The weave is designed to be exceptionally tight, preventing air or water from penetrating the tape itself. This tape will later become the base for the zipper chain and the sealing coating.

Step 3: Coiling the Teeth – Forming the Chain

This is where the zipper takes shape. The continuous nylon monofilament is coiled and heat-set onto one edge of the woven tape, forming the spiral teeth that interlock. The consistency of this coil is vital—any imperfection can compromise the final seal. Our machinery ensures every tooth is perfectly formed and securely attached.

Step 4: The Art of Sealing – The Airtight Coating Process

This is the transformative stage where a standard zipper becomes an airtight zipper.

The zipper chain is fed through a precision extrusion machine, which applies a layer of molten TPU or similar polymer evenly over the entire surface. This process carefully encapsulates the coiled teeth, filling the gaps between them and creating a continuous, waterproof, and airtight membrane. It’s a delicate balance of heat, pressure, and speed to ensure a uniform coat without compromising the zipper’s flexibility.

Step 5: Precision Assembly – Adding the Slider and Stops

Once the coated tape is cooled and cured, we move to assembly. The precision-molded slider is attached, and top and bottom stops are securely fixed. For our waterproof zippers, we often use a double slider for easy opening from both ends. Every component is designed to work in harmony with the coated chain, maintaining the integrity of the seal.

Step 6: The Proof is in the Testing – Rigorous Quality Control

A claim of being “airtight” is nothing without proof. Every batch of LEOT airtight zippers undergoes stringent testing.

• Air Pressure Tests: Zippers are sealed on a testing apparatus and subjected to air pressure. We measure for any drop in pressure over time to detect the slightest leak.
• Water Column Tests: For our waterproof zippers, we simulate heavy rain by applying a specific water pressure (e.g., 10,000mm) to the sealed zipper to ensure not a single drop passes through.
• Durability Cycles: Zippers are run through mechanical testers, opening and closing them thousands of times to ensure the coating doesn’t crack, peel, or wear down, and the slider continues to operate smoothly.

A zipper only leaves our facility once it has passed every single one of these checks.

The Final Product: Your Guarantee of Protection

The journey that began with raw yarn concludes with a reliable, high-performance LEOT zipper. It’s a component engineered for mission-critical applications where failure is not an option. Whether it’s protecting sensitive equipment from the elements or ensuring your outdoor adventure remains dry, our zipper is built to be the most dependable part of your product.

At LEOT, our process is more than just manufacturing; it’s a commitment to innovation, durability, and trust. We pour this dedication into every inch of zipper we produce.

Ready to integrate reliable protection into your designs?

Explore our full range of high-performance airtight and waterproof zippers and see the LEOT difference for yourself.