Trims specification series: Zippers

Trims are materials used to ornament or enhance garments. They are visible parts of garments that may be used to increase hanger appeal, provide product differentiation, relate to current fashion trends, and carry a theme through an entire collection. Trims include a broad range of materials and treatment that may be superficially applied or structurally incorporated into nearly any type of garment. Possibilities for trims are limited only by availability, design creativity, costs, and equipment to produce and apply them.

Trims are grouped into four categories: bindings, endings. Flat application and other trims. Selected type of trims, including embroidery thread, laces, appliques, knit trims, labels, sewing thread, zipper etc.

  • Type and source of trims:

Trims divide into two categories:

  1. Decorative trims: it is used or applied to enhance the aesthetic appeal of the garment not much related to garment function and performance. Example: embroidery, appliques, screen printing etc.
  2. Functional trims: it is integral part of garment they serve important pat in performance and aesthetic of a garment examples are button, knitted collars and cuffs.


Zippers are mechanical slide fasteners. A zipper closer a placket when two rows of interlining elements (teeth, scoops, or coil) are drawn together by a slider. Zippers allow garment to expand for dressing and to become smooth and fitted when closed. They may provide closer, smoother garment fit and accept more seam stress than buttons, snaps, or other closures. When used as closures, they are essential to the performance of garments since zipper failures often render garments unusable. Many zipper are also used for their aesthetic value such as those with elaborate or ornate pulls, decorative zipper tapes, or colour-coordinated chains.

Figure: nylon zipper, metal zipper and plastic zipper.

  • Characteristics of zippers:

Hundreds of different sizes and types of zippers are available. For example, YKK one of the world’s largest zipper manufacturers, produces approximately 2,000 zipper styles in over 400 basic and 1,000 specialty colours in its Macon, Georgia, etc.

Zipper selection may be based on input from merchandising, design, production, and quality assurance with assistance from the zipper manufacturer. Factors that contribute to the aesthetics and performance of zipper include type, size, and fabrication of parts, selection and application.

  • Zipper parts and materials:

Zipper consist of four main parts: two stringers which consist of tape and half the chain, one slider, and stop. Definition on the basis of ASTM D 2050-87, the zipper chain consists of two interlocking stringers of teeth, scoops, or coils that lock or unlock with the movement of the slider. Metal chain may be stronger than continuous coils and are often used in slacks and jeans where durability and strength are required. Metal teeth, made of brass, nickel, steel, or zinc are clamped onto zipper tapes. During zipper application, metal teeth may be removed without damaging the tape. This provides a space for stitching or bar tacking across the zipper. Teeth can also be pulled off the tape due to stress during use, meaning the zipper would have to be replaced or the garment discarded. Chains that do not rust or corrode are essential for garments that are wet processed, chemically treated, or garment dyed. Slider will not operate on corroded zipper.

Figure: parts of zipper.


Zipper terminology based on ASTM D 2050-87.


  • Element
A device designed for interlocking, capable of being affixed along the edge of the opposing edges of two tapes and being engaged and disengaged with the help of slider.
  • Continuous element zipper
A zipper consist of two continuously formed element; coils.
  • Separate element zipper
A zipper consist of two series of separately formed element; teeth or scoops.
  • Stringer
A tape, bead, and element assembly that constitute one side of the chain.
  • Chain
Formed by interlocking several elements of two stringers.
  • Shoulder
The bearing surface of an interlocking elements by which the chain is contained inside the flanges of the slider.

  • Tape
A narrow strip of material to which the material is attached.
  • Bead
An enlarger section on the inner edge of each tape to which interlockable element are fixed on a separate element zipper.

  • Slider
A part that opens and close the zipper.
  • Mouth
The opening in a slider that receives the chain.
  • Pull
A part connected to the zipper slider used to operate the slider.
  • Flanges
The edge of the slider formed to contain the chain.
  • Automatic lock slider
A slider that provide involuntary, positive locking action on the chain when the pull is released.
  • Pinlock slider
A slider that incorporates a projection on the pull that fits between adjacent interlocking elements of the zipper.
  • Camlock slider
A slider that incorporate curl projection on the pull that extended through a window on the slider to effect a locking action by pressing against the chain.

  • Stop
A device at the top and bottom of the zipper to prevent the sider from leaving the chain.
  • Bridge top stop
A part affixed immediately above the chain, holding the tops of the two stringer together.
  • Nonseperable zipper
A zipper having to stringer that are permanently attached to each other at one or both ends.
  • Separable zipper
A zipper fitted with special components at the bottom of a chain so as to permit complete disengagement and then reengagement of the two stringers.

Table (1)

  • Testing method of zipper:

US –ASTM (American society for testing and material).

Testing StandardItem
  • D2050
terminology related to zippers
  • D2051
test method for measuring the durability of zippers to laundering
  • D2052
test method for measuring the colourfastness of zippers to dry-cleaning
  • D2053
test method for measuring the colourfastness of zippers to light
  • D2054
test method for measuring the colourfastness of zipper tapes to crocking
  • D2057
test method for measuring the colourfastness of zippers to laundering
  • D2058
test method for measuring the durability of zippers to dry-cleaning
  • D2059
test method for measuring the resistance of zippers to salt spray (fog)
  • D2060
test method for measuring the dimension of zippers
  • D2061
test method for measuring the strength of zippers
  • D2062
test method for measuring the operability of zippers

Table (2)





Precaution on zipper use:

  • Rough Slider Operation

Do not force the slider even if it doesn’t move smoothly, or it may cause the elements to engage incorrectly.
Apply paraffin or wax on both the front and back surfaces of the elements, then move the slider back and forth to regain smooth operation.

  • Rough Slider Operation

Do not force the slider even if it doesn’t move smoothly, or it may cause the elements to engage incorrectly.
Apply paraffin or wax on both the front and back surfaces of the elements, then move the slider back and forth to regain smooth operation.

  • Fabric Caught in Slider

A slider may catch the fabric, hampering its operation.
Avoid forcing it to move or it will worsen the problem.
Slowly move the slider while pulling out the caught fabric.
Please allow enough room for the slider to move smoothly when sewing the zipper onto the fabric

  • Proper Laundry Procedure

Make sure to completely close all the zippers when using the washing/drying machines. Incompletely closed zippers may become entangled with other items and result in element or slider damage or damage to the other item’s fabric.
Long or slim slider pull-tabs may become caught in the drum holes, causing breakage, so the use of a laundry net for these items is recommended.
After the drying process, do not operate the zipper until the garment temperature has cooled down to normal.
Strong alkaline detergent or chlorinated bleach may affect zipper operation. In such cases, use softeners, paraffin or wax to regain the smoothness.
Do not pre-soak garments with zippers in a washing solution, or it may cause significant damage.

  • Application of zippers:
  1. Denim jeans.
  2. Shirt.
  3. Jacket.
  4. Bags.
  5. Shoes.
  • Zipper lock and Slider

The slider is a component that joins/separates a zipper when it is moved up/down along the chain.

Zipper sliders can be classified into various types, based on the types of zippers, namely, nylon sliders, metal sliders and plastic sliders, which differ from each other. Sliders installed on nylon zippers feature asymmetrical top and bottom sides, with the top side more flat than the bottom side, while sliders used for metal and plastic zippers share symmetrical top and bottom sides.

Apart from the classification based on the types of zippers, sliders can also be differentiated according to the functioning of the locking system. They work the best on the items appropriate for their functioning.

Locking is where the slider remains stagnant, without moving up and down the chain unexpectedly. Generally, zipper sliders can be seen in the following categories based on the locking mechanism:

  • Auto-lock sliders
  • Semi-auto lock sliders
  • Non-lock sliders

Auto lock sliders: Are those that will not move unless there is an external force on their pull tabs.

Non lock sliders: Are those that will unfasten even if slight force is applied on any slider part or even when the teeth are being pulled apart.

Semi auto lock sliders: Follow a simple mechanism wherein the locking and unlocking of the sliders depend on the movement of the pull tabs.

Application of different types of zipper sliders based on the locking mechanism.

Auto-lock sliders: garments, sportswear, outerwear, jackets, skirts, dresses, etc.

Non-lock sliders: bags, handbags, luggage, tents, bed covers, etc.

Semi-auto lock sliders: jeans and pants

Locked at the top zip Auto-lock slider

Auto-lock slider: Within this slider there is a locking mechanism activated by a leaf spring.

Locked at the top: This locking mechanism secures the slider position at the top of the zip immediately as the puller is released.

Opening/closing: Similarly, as soon as the puller is tensioned /pulled the lock is disengaged and the slider can be moved freely

download.jpg lock (1).png

Non-lock sliders: bags, handbags, luggage, tents, bed covers, etc.

Non lock sliders are those that will unfasten even if slight force is applied on any slider part or even when the teeth are being pulled apart.

Non Lock Slider: The pull-tab does not lock at any position on the body. No locking mechanism. Flat-lock Slider Flat lock 2 Flat lock 3 .Flat-lock Slider/semi auto lock slider: Semi Auto-lock / Flat-lock slider – This slider is fitted with a locking mechanism that is lifted /operated using a cam action.

Locked at the top To disengage the locking mechanism and move the slider it is necessary to lift the puller to 90 degrees to fully withdraw the locking pin.

Opening/Closing: To lock the slider in position the puller should rest flat on the body of the slider, the locking pin will then engage in the teeth holding the slider in place.

The application scenario of widely used zipper sizes and types are given in the below table:

Size #ItemSlider and Locking Recommendation Fabric Type Application
3aauto-lock & semi-auto locklightpocket zip, front fly, sleeves open
3Nylonauto-lock & non-lockultralight,lightpocket zip, blanket cover, cushions, front fly, half placket, front zipper, sleeves open
3Nyloninvisible (mesh type)ultra lightskirt, dress, pocket zip
3Nyloninvisible (woven type)lighttrousers, skirt, dress, cushions, half placket
3Plasticauto-locklightpocket zip, sleeves open, front zip
3L Typepin-locklight to mediumtrousers, skirt, front fly
4Metalsemi-auto lockmediumfront fly in jeans
4Nylonauto-lock & non-lockmediumpocket zip and front fly
5Metalsemi-auto lock & auto lockMedium and medium heavyfront fly
5Metalauto-lockmedium and medium heavyfront zip and pocket zip
5Nylonauto-lock & semi-auto lockmedium and medium heavyfront zip, pocket zip, leg bottom, sleeves, detachable legs, detachable inner jacket
5Plasticauto-lockmedium and medium heavyfront zip, detachable inner jacket, pocket zip
8Coilauto-lockmedium heavy and heavycamping tent & sleeping bag

Table (3)

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