Zipper: Types, Parts, Size, Manufacturing and Uses

What is Zipper?
A zipper, zip, fly, or zip fastener, formerly known as a clasp locker; is a popular device for temporarily joining two edges of fabric. It is used in clothing, luggage, and other bags, sporting goods, camping gear, and other daily-use items. The ‘zipper’ was introduced in 1893 at the Chicago World’s Fair then with the name of ‘Clasp Locker’. Initially, during the 1930s zippers were elements in children’s clothing for aiding them to dress themselves more easily. Zippers came into public interest in 1937 through the fashion designers in France who used them on men’s trousers.

Objectives of a Zipper:
The main objectives of zippers are

1. To increase or decrease the extent of an opening to restrict or permit the passage of items.
2. To join or isolate two panels of a garment, as in front of a dress or skirt.
3. To detach or attach a detachable panel of the garment from another, as in the adaptation between trousers and shorts.
4. To decorate an item.

Different Parts of a Zipper:
The construction and different parts of a zipper are shown in Figure 1.

Where,

1 – Top tape extension
2 – Top stop
3 – Slider
5 – Tape
4 – Pull tab
6 – Chain width
7 – Bottom stop
8 – Bottom tape extension
9 – Single tape width
10 – Insertion pin
11 – Retainer box
12 – Reinforcement film

The bulk of a zipper includes tens or hundreds of precisely shaped plastic or metal teeth which are attached to two pieces of fabric tape. These teeth could be either individual or fashioned from an endless coil, known as elements. The slider moves alongside the rows of teeth which have to be operated manually. The Y-shaped network inside the slider interlocks or separates the opposing rows of zipper teeth, based on the direction of the slider’s movement. In zipper construction, either chain zippers where two sets of interlocking teeth are used or coil zippers where coils are used which are attached to a band of fabric tape.

Different Types of Zippers:
There are various types of zippers. Types of zippers can be classified in the following way,

1. Types of Zippers Based on Construction
2. Types of Zippers Based on Material

A. Types of zippers based on construction:
The different types of zippers based on the construction are shown in Figure 2.

1. Coil zippers: This is the most frequently used type of zipper. It runs on two zipper coils on two sides of the fabric tape. The two kinds of coils zippers are spiral coil zipper, with a cable reinforced inside the coil, and a ladder zipper known as ‘Ruhrmann type’.
2. Invisible zippers: It has teeth at the rear side of the tape and the color of the teeth normally matches with the garment color. The slider gives an invisible appearance. These zippers are normally coil zippers and are mainly utilized in skirts and dresses.

   

3. Reverse coil zippers: Unlike an invisible zipper where the coil is also on the back, the reverse coil shows stitching on the front side and the slider will accommodate a variety of pulls (the invisible zipper requires a small, tear-drop pull due to the small slider attachment). Water-resistant zippers are generally configured as reverse coils so that the PVC coating can cover the stitching.
4. Metallic zippers: These zippers are generally made of stainless steel, zinc, brass, nickel or aluminium alloy and are mostly found in jeans. The metal pieces are shaped into the form of teeth and are positioned in a zipper tape at uniform intervals. The metal zippers could be colored in a variety of colors to match the color of the garment.
5. Magnetic zippers: These allow for one-handed closure and are used in sportswear.
6. Plastic moulded zippers: It is like metal zippers excluding the fact that it is made of plastic material. These types of zippers can be manufactured in a range of colors to match the garment color. Polyethylene resins and particularly polyacetal resins are commonly used to produce plastic zippers.
7. Open-ended zippers: These zippers are generally found in jackets and have a ‘box and pin’ type mechanism to interconnect the two sides of the zipper. It could be coil, metallic, invisible or plastic zippers. In open-end zippers, both ends are separated from each other as shown in Figure 4.

   

8. Closed-ended zippers: This kind of zipper is used regularly in baggage and is closed at both ends. The close-ended zippers are nonseparating and are usually opened and closed by means of a slider as shown in Figure 5. These zippers are used on trousers, jeans, jacket or shirt pockets, etc.

   

B. Types of Zippers Based on Material:
The kinds of zippers based on material are given below.

1. Polyester Zippers:
Polyester zippers are classified as-

• CFC – coil filler cord type
• CH – coil without cord type
• LFC – ladder type coil, used on trousers
• Invisible – concealed coil, used for ladies garments

2. Moulded Zippers:
The teeth of these zippers are produced by injection moulding using high-grade engineering plastic materials.

3. Metal Zippers:
The teeth of the zippers are stamped out of metal strips such as brass, bronze, aluminium or nickel alloys.

4. Innovative Zippers:
Due to the specific performances of textile and clothing, requirement of specialty zippers are also necessary to meet the functional performance of the garments. As a result, innovations were made to produce novel types of zippers such as flame-resistant zippers, airtight and watertight zippers, chemical-resistant zippers, zippers having electrical conducive yarn, zipper tape printed with ink-jet, environmentally conscious zippers, etc.

Manufacturing Process of Zippers:
The process sequence of zipper manufacturing is shown in Figure 6.

• Weaving of textile fabric: The cotton or some other blended yarn in both warp and weft are normally used for weaving a narrow fabric in a needle loom to produce a woven edge braiding. The zipper must be processed through weaving, cutting and winding processes before the complete edge braiding of the zipper.
• Zipper chain forming: The resin (if it is polyester) is fed into the injection moulding machine to form a zigzag line.
• Zipper slide head and end stopper: Metal or aluminium alloy is fed into the die casting machine to produce a slider and end stopper with required size and shapes.
• Sawing and fitting: The fabric tape and zipper chain are attached together using a sewing machine. After that, the top and bottom stopper of the zipper and the slider are fitted and adjusted.

Zipper Size:
Zippers are available in a range of sizes such as 3, 4, 5, 6, 7, 8, 9, 10, 12, etc., which are industry standards and does not imitate any dimensions of zipper, however, the larger the zipper size, the stronger the zipper. Zipper length denotes the length of the zipper among the topmost point of the top stop and the bottom most point of the bottom stop.

Applications of Zippers:
The common applications of zippers in different areas are given below.

1. Ladies’ and children’s garments: Coil filler cord (CFC), coil without cord type (CH) or invisible zippers; mostly closed-end zippers are used.
2. Jackets and overcoats: Metal or moulded open end or two-way separating zippers.
3. Trousers: Three ladder type coil (LFC), CFC with auto lock, closed end zippers.
4. Denim and casual wear: Robust closed end metal zippers.
5. Luggage items: CFC is most commonly used. Zippers in long chain rolls and sliders are sold separately.

Conclusion:
Zipper is one of the most important garment accessories. It plays a crucial role in the garment industry, offering several important benefits that contribute to the functionality, design, and overall appeal of garments. Zippers are not only used for functional purposes but also aesthetic choice, contributing to the visual appeal of products.

References:

1. Apparel Manufacturing Technology by T. Karthik, P. Ganesan, and D. Gopalakrishnan
2. Garment Manufacturing Technology Edited by Rajkishore Nayak and Rajiv Padhye
3. Practice of Garments Merchandising and Management by Engr. Md. Faruk Hosen

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