polypropylene fiber

Classification

Polypropylene fibers can be divided into long fibers, short fibers, spunbond nonwovens, meltblown nonwovens, etc.
Polypropylene long fibers can be divided into ordinary long fibers and fine denier long fibers (single fiber fineness ≤ 2.2 dtex, which can be used to produce clothing and decoration and some industrial filament products. Polypropylene fine denier long fibers have good luster, soft touch, good drape and low density. They are suitable for the knitting industry. When interwoven with cotton, viscose, silk, spandex, etc. into cotton-covered polypropylene and silk-covered polypropylene products, they are ideal materials for making high-end sportswear, T-shirts, etc.
The production process of polypropylene staple fibers mostly adopts a porous, low-speed, continuous process, that is, a short spinning process. Polypropylene staple fibers are blended with cotton to make polypropylene-cotton fine cloth and sheets, that is, fibers blended with viscose can be made into blankets, polypropylene pure spinning and blended wool yarn, polypropylene blankets, carpets, polypropylene cotton cigarette filters. The thickness of fibers for sanitary products is 1.5-2.5dtex, while the thickness of fibers for floor fabrics is 5-10 dtex. The fiber length is 1.5-200.0 mm, depending on the purpose of the fiber. The length of short fibers used for concrete is 1.5-200.0 mm, the length used for diapers is generally 40.0 mm, and the length used for floor fabrics is 60.0 mm.
Spunbond non-woven fabrics, also known as filament non-woven fabrics, are made by melting polypropylene raw materials and then extruding, spinning, stretching, laying nets, and bonding. It has the characteristics of short process, low cost, high productivity, excellent product performance, and wide range of uses. Polypropylene non-woven fabrics are widely used in various fields of production and life (such as disposable medical and sanitary products, disposable anti-fouling clothing, agricultural fabrics, furniture fabrics, linings for the shoe industry, etc.).
The fibers produced by meltblown non-woven fabric technology are very fine (up to 0.25μm). Meltblown fabrics have a large specific surface area, small pores and high porosity, so their application characteristics such as filtration, shielding and oil absorption are difficult to obtain by non-woven fabrics produced by other separate processes. Meltblown non-woven fabrics are widely used in medical and health care, thermal insulation materials, filtration materials and other fields

Performance characteristics

(1) Lightweight
The density of polypropylene fiber is 0.90-0.92 g/cm3, which is the lightest among all chemical fibers. It is 20% lighter than nylon, 30% lighter than polyester, and 40% lighter than viscose fiber. Therefore, it is very suitable for filling winter clothing or fabrics for ski suits, mountaineering suits, etc.
(2) High strength, good elasticity, wear resistance and corrosion resistance
Polypropylene fiber has high strength (same in dry and wet states) and is an ideal material for making fishing nets and cables; it has good wear resistance and resilience, and its strength is similar to that of polyester and nylon. Its rebound rate is comparable to that of nylon and wool, and is much greater than that of polyester and viscose fibers; polypropylene fiber has poor dimensional stability, is easy to pill and deform, is anti-microbial, and is not moth-eaten; its chemical resistance is better than that of general fibers.
(3) It has electrical insulation and warmth retention
Polypropylene fiber has a high resistivity (7×1019Ω.cm) and a low thermal conductivity. Compared with other chemical fibers, polypropylene fiber has the best electrical insulation and warmth retention, but it is prone to static electricity during processing.
(4) Poor heat resistance and aging resistance
Polypropylene fiber has a low melting point (165~173℃) and poor stability to light and heat. Therefore, polypropylene fiber has poor heat resistance and aging resistance and is not resistant to ironing. However, its anti-aging performance can be improved by adding anti-aging agents during spinning.
(5) Poor hygroscopicity and dyeability
Polypropylene fiber has the worst hygroscopicity and dyeability among chemical fibers. It absorbs almost no moisture and its moisture regain is less than 0.03%. Fine denier polypropylene fiber has a strong wicking effect, and water vapor can be removed through the capillaries in the fiber. After being made into clothing, the clothing is more comfortable, especially ultra-fine polypropylene fiber. Due to the increased surface area, it can transfer sweat faster and keep the skin comfortable. Because the fiber does not absorb moisture and has a small shrinkage rate, polypropylene fabrics are easy to wash and dry quickly.
Polypropylene fiber has poor dyeability, light color, and poor dyeing fastness. Ordinary fuels cannot dye it. Most colored polypropylene fibers are produced by pre-spinning coloring. The raw material can be dyed by solution, modified by fiber, and mixed with fuel complexing agent before melt spinning.