Zipper: The "throat" of A Bag, Determining Its Life And Death

02/01/2026
image

A zipper, no more than tens of centimeters long and the weight no more than ten grams, is the deadliest organ on the bag and seemingly simple opening and closing device, if it is healthy, no matter how old the bag is, it can accompany you to charge into battle. Once it is "infarct", no matter how expensive the leather or the gorgeous hardware is, it will instantly lose its speech. Now, let's take a look at below several aspects to know about this accessory that is extremely important for bags:

  • Definition of zipper

A connection composed of two flexible tooth chain straps that are mutually cleaved and a slider that can be repeatedly opened and closed.

  • Three classification systems of zippers
  1. Classification by material

Type

                Material

characteristic

Nylon zipper

Polyester monofilament spiral weave

Soft and lightweight

Plastic zipper

POM injection molding

Bright colors

Metal zipper

Copper/aluminum/zinc alloy teeth

Strong and durable

Invisible zipper

Special braided hidden teeth

Closed seamless

Waterproof zipper

PVC/TPU coating lamination

Completely sealed

  1. Classification by structure

1）Closed tail zipper: fixed at both ends, non-separable. ·

2）Open tail zipper: can be completely separated into two pieces. ·

3）Two-way zipper: double slider in opposite direction. 

4）Double opening zipper: can be opened at both end.

  1. Classification according to tooth number The tooth number is the width of the teeth (unit: mm), which determines the strength of the zipper:

1）3#-5#: light and light fabric(suitable for4 small bag such as cosmetic bag or shopping bag or wallet purse etc. or inner pocket).

2）7#-8#: regular thickness.  ·

3）10# or more: heavy duty use (suitable for oversize & overweight bags such as duffel travel bag or tool bag etc.)

  1. Here is the chart for above zippers used in the bags:

三，Functional dark war: the "hidden skill"of the zipper determines the life and death of the scene

1）Anti-theft - self-locking + double-layer: pull tab Subway pickpockets love to "pull in seconds" to get things and the thief can hardly pull it open with one hand.

2）Waterproof - hot press lamination + TPU coating: The zipper teeth in the TPU "tunnel", the waterproof level can reach IPX-6, and the humidity in the bag only increases by 4% in 2 hours of heavy rain.

3）Lightweight - resin + hollow slider: Japan's YKK NATULON® Ocean series, the tooth strap is made of ocean-recycled plastic, the slider is hollowed out by 30%, and the weight of the whole zipper is reduced by 42%, making the 30L hiking bag 110 g lighter as a whole, and the effort saved by long-distance hiking ≈ bring an extra bottle of water.

四，Zipper life formula: Don't let your bag lose to "metal fatigue"

1. Industry common test:

  1. lateral tensile force ≥60N, longitudinal tensile force ≥90N.
  2. reciprocating pulling 5000 times without tooth drop.
  3. Salt spray does not rust for 48 hours.
  4. Chain Cross-wise Strength Element Displacement≤ 0.4 mm.
  5. No red rust Color Fastness ≥ Level
  6. Sweat and wash resistance Heavy metal/azo/nickel release – in accordance with EU REACH & OEKO-TEX 100.
  1. Maintenance tips:
  1. "dry wipe + wax wipe" once a month to block the source of corrosion;
  2. When the packing is seven minutes full, leave 2 cm of "breathing volume" for the zipper;
  3. After traveling through the security check, wipe it with a wet wipe - the X-ray curtain of the airport conveyor belt is black and gray with graphite, which is the invisible killer of the electroplating layer.

But in reality, the triple debuff of cosmetics containing oil, hand sweat and salt, and sunlight ultraviolet rays will make metal fatigue report 30% early.

五，Design trends: Zippers are "disappearing", but they are more important

1）Invisible Zipper: The chain teeth are hidden on the inside of the wall, and there is only a "knife seam" left on the outside, which is used by Coach 1941 and Old Celine Box.

2）Magnetic + zipper "double insurance": The magnetic suction bears 80% of the closing force, and the zipper is only responsible for 20%, extending the life by 3 times, which is called "zipper perpetual motion machine".

3）Replaceable zipper module: One of brand from Swedish turns the zipper car into an independent "insert", and users can disassemble and change different colors in 3 minutes. Environmental protection gimmick + DIY appearance, so that the second-hand platform will increase the price by 15%.

六，Trivia: The "carbon footprint" of a zipper ≈ 4 cups of latte from YKK 2025 Sustainability Report:

1 metal zipper emits 1.2 kg of CO₂e throughout its life cycle, of which 70% comes from copper mining. The brand's switch to recycled copper has reduced to 0.4 kg CO₂e, which is equivalent to 4 km less car mileage. The next selling point is no longer "smooth", but "environmental protection" - the EU 2026 will make it mandatory to mark zipper carbon emissions on the tag, and brands that change to recycled materials in advance will get green premium tickets first.

Thus, the zipper is not a supporting role, but the "throat" of the handbag. It uses a few grams of metal and is palm at the same time.

Back to list