The Chinese trade name of synthetic fiber isoplasmic polypropylene fiber made with the by-product of petroleum refining propylene as raw material. Also known as polypropylene fiber. The raw materials are rich in sources, the production process is simple, and the product price is relatively cheaper than other synthetic fibers. The physical and mechanical properties of fibers are: high strength (short fibers are 4-6 grams/den, filaments are 5-8 grams/den), wet strength and dry strength are basically the same, specific gravity is small (0.91), wear resistance and corrosion resistance, etc. The world's annual output of polypropylene fiber exceeded 1 million tons in 1980.

Chemical fiber raw materials are divided into polyester, polypropylene, acrylic and nylon. Among them, polypropylene is the product name of polypropylene fiber. Polypropylene began industrial production in 1957. Since the raw materials only require propylene, it has extremely rich sources, low prices and simple production technology. It is currently the cheapest synthetic fiber. Polypropylene has good performance and fast development speed. It ranks fourth in the world's production after polyester, nylon and acrylic.

1. Characteristics of polypropylene: Polypropylene is the species with the smallest total relative density of all synthetic fibers, so it is the lightest mass and the area that the fiber per unit weight can cover is the largest. Its strength is similar to that of medium and high-strength varieties of synthetic fibers, but its strength does not change when it is wet, which is better than nylon. However, its flat wear resistance is second only to nylon, and its bending wear resistance is slightly worse, and it has significant stability to inorganic acids and alkalis. It has good elasticity, very little hygroscopicity, and small shrinkage rate of fabrics. It has excellent electrical insulation and mechanical properties, and is widely used in the industry to manufacture ropes, packaging materials, fishing nets, parachutes, etc. Of course, polypropylene has its disadvantages, such as poor light resistance, poor dyeing, high electrostatic property, poor flame resistance, and difficult dyeing.

2. Production of polypropylene: The polypropylene that produces polypropylene fibers is made of solution polymerization. Its thermal decomposition temperature is 350~380C and its melting point is 150~176C, so the soft spinning method is used.

3. Washing of polypropylene material: When washing polypropylene, it cannot be soaked in boiling water, and cannot be dry cleaned, and it will become hard once it is washed.