DTY fiber is crimped, FDY fiber is straight.

The elongation and shrinkage of polypropylene FDY yarn are two concepts. Elongation refers to the percentage of polypropylene filament elongation after being stressed; shrinkage refers to the percentage of the ratio of the polypropylene filament's shrinkage length to the original length after being heated. Polypropylene is an important type of synthetic fiber. It is the Chinese trade name of synthetic fiber isotactic polypropylene fiber made from propylene, a by-product of petroleum refining. Also known as polypropylene fiber.

Refers to incompletely stretched chemical filaments with an orientation degree between unoriented filaments and drawn filaments obtained by high-speed spinning. Compared with undrawn yarn, it has a certain degree of orientation and good stability, and is often used as a special yarn for stretched false twisted textured yarn (FDY). FDY is a stretch-textured yarn. It is made by using POY as a raw yarn and processed by stretching and false-twisting. It often has a certain degree of elasticity and shrinkage.

Polypropylene FDY yarn is an environmentally friendly material, non-polluting, non-toxic, environmentally friendly, light weight, chemical resistance, recyclable and granulating, and other functions.