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 (monofilament fineness ≤ 2.2 dtex, which can be used in the production of clothing and decoration and some industrial filament products. It has good properties and low density. It is suitable for the knitting industry. When it is interwoven with cotton, viscose silk, silk, and spandex to form cotton cover C, silk cover C and other products, it is an ideal material for making sportswear, T-shirts, etc.

Most of the production process of polypropylene staple fiber adopts porous, low-speed, continuous process, namely short spinning process. Polypropylene staple fiber blended with cotton can be made into polypropylene cotton muslin and bed sheets, that is, fiber and viscose blended can be made into blankets, polypropylene pure and blended wool, polypropylene blankets, carpets, and polypropylene cotton cigarette filters. Fibres for hygiene products are 1.5-2.5 dtex, while those for floor fabrics are 5-10 dtex. The fiber length is 1.5-200.0 mm, depending on the use of the fiber. The length of short fibers used for concrete is 1.5-200.0 mm, the length for diapers is generally 40.0 mm, and the length for ground fabrics is 60.0 mm.

Spunbond non-woven fabrics, also known as filament non-woven fabrics, are made of polypropylene raw materials after melting, extrusion spinning, stretching, laying, 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 antifouling clothing, agricultural cloth, furniture cloth, lining of shoe industry, etc.).

The fibers produced by the melt-blown non-woven technology are very fine (up to 0.25 μm). The melt-blown non-woven fabric has a large specific surface area, small pores and large porosity, so its application characteristics such as filtration, shielding and oil absorption are used. It is difficult to have non-woven fabrics produced by other separate processes. Meltblown non-woven fabrics are widely used in medical and health care, thermal insulation materials, filter materials and other fields.

In the early days, propylene polymerization can only obtain paper products with low degree of polymerization, which are non-crystalline compounds and have no practical value. In 1954, Ziegler and Natta invented Ziergler-Natta catalyst and made crystalline polypropylene with high stereoregularity, called isotactic polypropylene or isotactic polypropylene. This research achievement has opened up a new direction in the field of polymerization, and laid the foundation for the large-scale industrial production of polypropylene and its wide application in plastic products and fiber production.

In 1957, the industrial production of polypropylene was first realized by Montecatini Company of Italy. From 1958 to 1960, the company used polypropylene for fiber production and developed a polypropylene fiber named Meraklon, which was also produced in the United States and Canada.

After 1964, the polypropylene film split fiber for bundling was developed, and the film was fibrillated into textile fibers and carpet yarns.

In the 1970s, short-run spinning technology and equipment improved the polypropylene fiber production process. During the same period, bulked continuous filaments began to be used in the carpet industry. Currently, 90% of the world's carpet backing and 25% of the carpet veil are made from polypropylene fibers.

After 1980, with the development of polypropylene and new technologies for making polypropylene fibers, especially the invention of metallocene catalysts, the quality of polypropylene resins has been significantly improved. Due to the improvement of its tacticity (isotacticity up to 99.5%), the intrinsic quality of polypropylene fibers is greatly improved. In the mid-1980s, polypropylene fine fibers replaced some cotton fibers for textile fabrics and non-woven fabrics. Coupled with the development of one-step BCF spinning machines, air texturing machines and composite spinning machines, as well as the emergence and rapid development of non-woven fabrics, the use of polypropylene fibers in decorative and industrial applications has been further expanded. In addition, the research and development of polypropylene fibers in various countries in the world are also quite active, and the popularization and improvement of differential fiber production technology has greatly expanded the application fields of polypropylene fibers.

The performance characteristics of polypropylene fiber:

Lightweight: Polypropylene fiber is relatively light among all chemical fibers, 20% lighter than nylon, 30% lighter than polyester, and 40% lighter than viscose fiber, so it is very suitable for winter clothing. Fabrics for mountaineering suits, etc.

High strength, good elasticity, wear resistance and corrosion resistance: polypropylene has high strength (same in dry state and wet state), and is an ideal material for manufacturing fishing nets and cables; good wear resistance and resilience, similar in strength to polyester and nylon, The elastic rate is comparable to that of nylon and wool, and is much larger than that of polyester and viscose fibers; polypropylene has poor dimensional stability, easy to pilling and deformation, anti-microbial, and no moth; chemical resistance is better than general fibers.

It has electrical insulation and warmth retention: polypropylene fiber has high resistivity (7×1019Ω.cm) and low thermal conductivity. Compared with other chemical fibers, polypropylene fiber has good electrical insulation and warmth retention, but processing It is easy to generate static electricity.

Poor heat resistance and aging resistance: The melting point of polypropylene fiber is low (165~173 ° C), and the stability to light and heat is poor. Therefore, polypropylene fiber has poor heat resistance and aging resistance, and is not resistant to ironing. But the anti-aging performance can be improved by adding anti-aging agent during spinning.

Poor hygroscopicity and dyeing properties: The hygroscopicity and dyeing properties of polypropylene fibers are relatively poor among chemical fibers, and they hardly absorb moisture, and their moisture regain is less than 0.03%. The fine denier polypropylene fiber has a strong wicking effect, and the water vapor can be removed through the capillary in the fiber. When made into clothing, it is more comfortable, especially the ultra-fine polypropylene fibers, which can transfer sweat faster due to the increased surface area and keep the skin dry. Because the fiber does not absorb moisture and has a small shrinkage rate, the polypropylene fabric has the characteristics of easy washing and quick drying.

Polypropylene has poor dyeability, light color and poor color fastness. Ordinary fuels cannot be dyed, and most of the colored polypropylene fibers are produced by dyeing before spinning. Dope dyeing and fiber modification can be used, and fuel complexing agent can be blended before melt spinning.