Nylon Buttonhole Webbing: near flame, it melts and burns, drips and foams. Does not continue to burn. It tastes like celery. Hard, round, light, brown to gray, bead-like.
Polyester Buttonhole Webbing: It melts when near the flame, melts, drips and foams. It can continue to burn, a few have smoke. Very weak sweetness. Hard round, black or light brown.

Both cotton fiber and hemp fiber burn immediately near the flame and burn quickly. The flame is yellow and emits blue smoke. The difference between the burning smell and the ashes after burning is that the cotton belt burns to give out the smell of paper, while the hemp cotton burns to give off the smell of plant ash; after burning, the cotton has very little powder ash, which is black or gray, and the hemp cotton produces a small amount. Off-white powder ashes.

The scientific name of nylon (nylon) is polyamide fiber. It quickly crimps and melts into a white gel near the flame. It melts and drops and foams in the flame. There is no flame when burning. It is difficult to continue burning without the flame. It emits a celery smell. After cooling down The light brown melt is not easy to grind. The scientific name of polyester is polyester fiber. It is easy to ignite, and it melts when it is near the flame. When it burns, it emits black smoke while melting. It shows a yellow flame and emits an aromatic odor. Three ways to distinguish the good and bad of the webbing.

Chromatic aberration test: This can be observed with the naked eye. Look at its color, texture, and stitch edges. It should not be messy, it should be a very pure color.
Shallow knowledge of quality:
Burr: It is usually the burr of some yarns. This can also be observed with the naked eye. There should be no serious hairballs and hairs on both sides and seams of Buttonhole Webbing.
Skipped stitches: This can be observed by naked eyes. Buttonhole Webbing cannot have skipped stitches.