Most industrial webbing on the market is either polyester or nylon. They are hard to tell apart by hand and both far outlast cotton, so many orders are placed on price alone. The four differences below decide how long the finished product survives.
In water
This is the biggest difference. Nylon absorbs moisture; wet, it loses noticeable strength and stretches, and although it recovers on drying it does not always return to the original dimension. Polyester absorbs almost nothing and holds both strength and size wet or dry.
For backpacks, outdoor straps, cargo lashing or anything that meets rain, polyester is the safer call. Nylon suits indoor use, or cases where you actually want the stretch.
In sunlight
Polyester resists UV considerably better. Nylon left in the sun turns brittle and loses colour faster. That is why vehicle straps, awnings and outdoor gear tend to use polyester even though nylon starts with higher tensile strength.
Stretch
Nylon stretches more under load. That is a drawback when the strap must stay put, and an advantage when it needs to absorb shock, as in tow straps or fall-arrest applications. Polyester stretches little and feels firmer and more predictable.
- Firm, no creep, used outdoors: choose polyester.
- Shock absorption, heavy abrasion, indoor use: consider nylon.
- Bright shades that must hold over time: polyester takes dye more stably.
When in doubt, and the product may meet rain or sun, choose polyester. It is the lower-risk option for most orders.
Checking what you received
There is no reliable way to tell by eye. Ask the supplier to state the material on the delivery note and to retain a sample of each lot. If you need certainty, a textile laboratory can identify the fibre by burn or solvent test within a working day.
When ordering, describe the real service conditions rather than only naming a material: indoors or outdoors, loaded or not, how heavily, whether it meets salt water. The maker selects yarn and weave far more accurately when they know where the tape will live.
