Polypropylene (PP fiber) is the largest potential variety of the four major synthetic fibers and is already the second largest synthetic fiber variety. Polypropylene can be divided into staple fibers, filaments, non-woven fabrics, cigarette tow, bulked continuous filament (BCF), etc., mainly used for packaging, cigarette filters, carpets, non-woven fabrics, apparel and other products. In addition to taking fiber, polypropylene for industrial use is the most active market, and consumption in medical and hygiene materials is also growing rapidly. With the emphasis on project quality, the application of polypropylene non-woven fabrics in roads, reservoirs, and dam construction will increase rapidly. Polypropylene will certainly play a major role in the wide range of synthetic fiber applications, and the prospects are very broad.
Polypropylene first appeared in Italy in 1954. In 1959, Montecatini Corporation put into commercial production under the trademark “Meraklonâ€. Polypropylene is characterized by its low relative density, low melting point and glass transition temperature, high crystallinity, low moisture absorption, good chemical resistance and good mechanical properties. However, the heat resistance and light resistance are poor. In addition, due to the low price of raw materials and low energy consumption, polypropylene has a lower cost than other synthetic fibers. Polypropylene began to enter the market in the 1960s and polypropylene flat yarn gradually replaced jute as the basic raw material for the sack industry. In 1962, the Canadian Cellanese company developed short-range polypropylene spinning. In the same period, expanded continuous filament (BCF) began to be used in the carpet industry. At present, 90% of the world's carpet base fabrics and 25% of carpet veils are made of polypropylene.
Due to its excellent properties, polypropylene has a rich source of raw materials, a simple manufacturing process, and low cost. There are broad prospects for the application of clothing, decoration and industrial products. Therefore, the development of new products for polypropylene fiber is also emerging. Polypropylene functional fibers were first recognized in developed countries such as Japan and the United States.
Since the 1960s, Japan has increased its investment in the research of polypropylene functional fibers and high-performance fibers, continuously introduced new high-tech products, and emphasized its use in decoration and industrial applications to broaden the application of textiles. The United States has developed a variety of functional polypropylene such as antibacterial, flame retardant, antistatic, and antifouling. The research and development of polypropylene in various countries of Western Europe are also quite active. The conductive, electrothermal, bio-absorbable and degradable polypropylene has been successfully developed. At present, Japan's polypropylene functional textiles account for 39% of all textiles, and Mitsubishi recently launched Mitsubishi Pylen, an environmentally friendly polypropylene.
With the increase of polymer spinning technology, polypropylene has grown from denier to fine denier and ultra-fine denier. In the 1970s, the development of polypropylene fine denier fibers first began in the United States, Italy, the Czech Republic, and other countries; the ultrafine denier polypropylene is a new breed of polypropylene fibers that develops towards the thinning of artificial silk and fabrics, with the exception of the light weight of conventional polypropylene. With the advantages of good protection, high strength, corrosion resistance, wear resistance, etc., it also has the characteristics of softness, moisture conduction and comfort. Its fine denier and ultra-fine deniers are used to make sportswear, underwear, high-grade clothing and filter media. Excellent materials, they have unique, excellent performance.
In the mid-1980s, concrete-enhanced polypropylenes made progress. The United States and Western Europe have begun to use them in the construction industry. Since the 1990s, with the continuous improvement of the properties of polypropylene, the varieties of polypropylene have become more diversified. Dow Chemical Company and Monsanto Company occupy an important position in this field. 28% of American textiles are polypropylene functional textiles.
Although the development of China's polypropylene fiber started late, it developed rapidly. The average annual growth rate in the 1980s reached 36%, which is much higher than the global growth rate of polypropylene i2%. It is also significantly higher than the 16% growth rate of domestic synthetic fiber. In the 1990s, polypropylene in China still developed at a faster rate than the average growth of synthetic fiber. The annual demand for China's polypropylene fiber has exceeded 500,000 tons, of which high-grade non-woven fabrics and sports taking materials basically depend on imports.
China's research and development of polypropylene fiber has gone through a process from scratch for the past 20 years. Nowadays, research on the functionalization of polypropylene has entered a period of vigorous development. Not only are the varieties increasingly diversified, but most of the new functional polypropylenes are produced and researched in China. Such as fire-retardant fiber, anti-bacterial fiber, anti-ultraviolet fiber, far infrared fiber and other varieties have a certain amount of production.
Second, polypropylene development of new varieties
1. Polypropylene
Ordinary polypropylene fibers have a round cross-section, and the wax has a waxy appearance and a plasticized appearance, which affects the performance and appearance of the fabric. Therefore, a proper non-circular cross section must be used to eliminate or minimize the waxy feel. The cross section of the hole can be shaped like a star, a triangle, or a polygon. The section of the fiber also affects the volume, insulation, resilience, wicking effect, gloss, and dirt absorption