Identify the material of the webbing(2)

3. Acrylic and polypropylene (PP)
Acrylic fiber name polyacrylonitrile fiber, near fire softening and melting, black smoke after the fire, the flame is white, burning quickly after the flame, emitting the bitter smell of the fire meat, after burning the ash is irregular black lumps, handcuffs are brittle . Polypropylene fiber, polypropylene fiber, near the flame is melted, flammable, burning slowly from the fire and black smoke, the upper end of the flame is yellow, the lower end is blue, emitting oily smell, after burning, the ash is hard round light yellow brown granules, hand 捻 easy broken.
4, vinylon and polyvinyl chloride
The name of vinylon is not easy to ignite, the near flame melts and shrinks, and there is a little flame at the top when burning. When the fiber melts into a gelatinous flame, it has a thick black smoke, a bitter smell, and black after burning. Bead-like particles that can be crushed with your fingers. Polyvinyl chloride fiber, difficult to burn, is extinguished from the fire, the flame is yellow, the lower end of the green white smoke, the pungent pungent smell of spicy and sour, after burning, the ash is dark brown irregular lumps, the fingers are not easy to smash.
5, spandex and fluorocarbon
Polyurethane, the name of spandex fiber, burns near the edge of the fire. When burning, the flame is blue. It leaves the fire and continues to melt, giving off a special irritating odor. After burning, the ash is soft and fluffy black ash. Fluorine fiber PTFE fiber, ISO organization called it fluorite fiber, near flame only melt, difficult to ignite, not burning, edge flame is blue-green carbonization, melting and decomposition, gas is toxic, the melt is hard round black Beads. Fluorinated fibers are commonly used in the textile industry to make high performance sewing threads.
It is easy to identify fibers by combustion, but blended products are not easy to judge. A yarn is drawn from each of the warp and weft directions (ie, the direction of the straight and the transverse direction).