Resin (Plastic-Molded) Zippers: Types, Sizes & Applications

Resin zippers – also called plastic-molded or injection-molded zippers – are a popular choice for bags, luggage, outerwear, and industrial uses. Unlike nylon coil zippers that are made by winding a monofilament, resin zippers are formed by injecting molten plastic into a mold to create individual teeth on a tape. This process gives them a more uniform, sturdy tooth shape that resists bending and breaking.

If you are sourcing zippers for OEM production, understanding the differences between resin, nylon, and metal zippers is crucial. In this guide, we cover how resin zippers are made, available sizes, typical applications, and why Primo is a reliable supplier.

How Resin Zippers Are Made

Resin zippers are produced using injection molding. Primo uses the PM-013 resin injection molding machine to inject resin (plastic) directly onto the zipper tape, forming each tooth individually. This is not a die-cast process – it is pure injection molding. The tape itself is woven on our own PM-510 Jeso looms, ensuring consistent quality from the start.

After molding, the zipper goes through finishing steps: gapping (removing teeth where needed) on the PM-021 plastic gapping machine, applying top and bottom stops (PM-018 for open-end injection stops, PM-019 for closed-end injection stops), and slider insertion on PM-321/322. Finally, the zipper is cut to length on PM-081/082 robotic cutters.

Resin Zipper Sizes and Strength

Resin zippers come in several standard sizes, typically measured by the tooth width in millimeters. Common sizes include #3, #5, #8, #10, #15, and #20. Larger numbers mean wider, stronger teeth. The table below shows typical size ranges and their common applications.

Resin zippers offer good tensile strength and are resistant to corrosion and chemicals. They are lighter than metal zippers but more rigid than nylon coil zippers. For most consumer bags and apparel, #5 or #8 resin zippers provide the best balance of strength and flexibility.

Resin vs. Nylon vs. Metal Zippers

Choosing the right zipper material depends on your product’s requirements. Here is a quick comparison:

Resin zippers are often preferred for luggage and backpacks because they are lightweight, strong, and do not rust. They also hold their shape well, making them easy to slide.

Applications of Resin Zippers

Resin zippers are used in a wide range of products:

• Luggage and travel bags – Main compartment and pocket zippers
• Backpacks and school bags – Durable and weather-resistant
• Outerwear and jackets – Front closures and pockets
• Sporting goods – Golf bags, duffel bags, coolers
• Industrial covers and tents – Heavy-duty zippers for outdoor gear
• Promotional items and corporate gifts – Custom colors and logos

Because resin zippers can be molded in virtually any color, they are popular for branded products. Primo offers custom color matching and can add your logo on sliders or pulls.

Resin Zipper Components: Sliders, Stops, and Pulls

Resin zippers use sliders that are typically die-cast from zinc alloy using Primo’s PMM-006/007/008 molds. These sliders can be self-locking or non-locking, with various puller styles. Top and bottom stops on resin zippers are injection-molded: PM-018 forms the open-end insert pin and PM-019 forms the closed-end box stop.

If you need help choosing the right slider or stop for your resin zipper, see our guide on Zipper Slider Accessories: Pullers, Stoppers & Components for OEM Buyers.

Quality and Certifications

Primo resin zippers are produced in a vertically integrated factory. We weave our own tape, mold our own teeth, and assemble the final product. This gives us full control over quality. Primo resin zippers are OEKO-TEX certified, meaning they are free from harmful substances and safe for skin contact. We also offer custom testing for strength and durability per your specifications.

Customization Options

As an OEM supplier, Primo can customize resin zippers in many ways:

• Length – Cut to your exact measurement
• Color – Match any Pantone or RAL code
• Slider type – Auto-lock, non-lock, reversible, or custom
• Puller design – Standard, custom logo, or special shape
• Stops – Open-end or closed-end, injection or metal
• Packaging – Individual pieces, bulk rolls, or barcoded

For a broader overview of zipper types, read our How to Choose the Right Zipper: Nylon, Metal, Plastic and Specialty Types Explained.

Why Choose Primo for Resin Zippers?

Primo is not just a zipper manufacturer – we also build the machines that make our zippers. Our Jeso machinery division (primozippermachine.com) designs and produces the PM-013 injection molder and other equipment. This vertical integration means we can control every step of production, from tape weaving to final assembly. You get consistent quality, competitive pricing, and reliable supply.

We serve OEM buyers worldwide, from small brands to large manufacturers. Our team can help you select the right resin zipper for your product and provide samples for testing.

If you are looking for a trusted resin zipper supplier, contact Primo today. Request a quote or ask for samples – we are ready to support your next project.