polypropylene fiber

The Chinese trade name of synthetic fiber isotactic polypropylene fiber made from propylene, a by-product of petroleum refining. Also known as polypropylene fiber. The source of raw materials is abundant, the production process is simple, and the product price is relatively lower than other synthetic fibers. The physical and mechanical properties of the fiber are: high strength (short fiber is 4-6 grams/denier, filament is 5-8 grams/denier), the wet strength and dry strength are basically the same, the specific gravity is small (0.91), and it is resistant to abrasion and abrasion. Corrosion etc. The world's annual output of polypropylene fiber exceeded 1 million tons in 1980.

The varieties of polypropylene fibers include filaments (including undeformed filaments and bulky textured filaments), short fibers, bristles, split-membrane fibers, hollow fibers, shaped fibers, various composite fibers, and non-woven fabrics. The main purpose is to make carpets (including carpet base cloth and suede), decorative cloth, furniture cloth, various ropes, strips, fishing nets, linoleum, construction reinforcement materials, packaging materials and industrial cloths, such as filter cloth and bag cloth Wait. In addition, the application in clothing is becoming more and more extensive. It can be blended with a variety of fibers to make different types of blended fabrics. After knitting, it can be made into shirts, outerwear, sportswear, socks, etc. The quilt made of polypropylene hollow fiber is light, warm and elastic.

Polypropylene does not contain chemical groups that can bind to dyes in the macromolecular structure, so dyeing is more difficult. Usually the melt coloring method is adopted, the pigment preparation and the polypropylene polymer are uniformly mixed in a screw extruder, and the color fastness of the colored fiber obtained by the melt spinning is very high. Another method is to copolymerize or graft copolymerize with acrylic acid, acrylonitrile, vinyl pyridine, etc., to introduce polar groups that can be combined with dyes on the polymer macromolecules, and then directly dye with conventional methods. In the process of polypropylene production, various additives are often added to improve dyeability, light resistance and flame resistance.

The scientific name is polypropylene fiber. It melts near the flame and is flammable. It burns slowly and emits black smoke from the fire. The upper end of the flame is yellow and the lower end is blue, emitting a smell of petroleum. .

It is a fiber made from propylene as a raw material through polymerization and melt spinning. Polypropylene officially began industrial production in 1957 and is a rising star among synthetic fibers. Because polypropylene fiber has the advantages of simple production process, low product price, high strength, and light relative density, polypropylene fiber has developed rapidly. At present, polypropylene fiber is the fourth largest variety of synthetic fibers, and it is the lightest fiber among common chemical fibers.

The production of polypropylene fiber includes staple fiber, filament and split film fiber. Polypropylene film fiber is made by first making polypropylene into a film, and then stretching the film to split it into a network of fibrils.

Civil use: it can be pure spinning or blended with wool, cotton or viscose to make various clothing materials. It can be used to knit all kinds of knitwear such as socks, gloves, sweaters, knitted pants, dishcloths, mosquito nets, quilts, warm padding, wet diapers, etc.

Industrial use: carpets, fishing nets, canvas, hoses, concrete reinforcement materials, industrial fabrics, non-woven fabrics, etc. Such as carpets, industrial filter cloths, ropes, fishing nets, building reinforcements, oil-absorbing blankets and decorative cloths. In addition, polypropylene film fibers can be used as packaging materials.

The main physical and chemical properties of polypropylene

1. Form The longitudinal surface of polypropylene is straight and smooth, and the cross section is round.

2. Density The biggest advantage of polypropylene fiber is its light texture. Its density is only 0.91g/cm3, which is the lightest variety among common chemical fibers. Therefore, polypropylene fiber of the same weight can obtain a higher coverage area than other fibers.

3. Strength and elongation Polypropylene has high strength, large elongation, high initial modulus and excellent elasticity. Therefore, polypropylene fiber has good abrasion resistance. In addition, the wet strength of polypropylene is basically equal to the dry strength, so it is an ideal material for making fishing nets and cables.

4. Hygroscopicity and dyeing properties: light weight and good warmth retention; almost no moisture absorption, but strong absorption capacity, and obvious moisture absorption and perspiration effect; polypropylene fiber has very little moisture absorption and almost no moisture absorption, and the moisture regain rate under general atmospheric conditions is close to zero. But it has a wicking effect and can transmit water vapor through the capillary in the fabric, but it does not have any absorption effect. Polypropylene fiber has poor dyeability and incomplete chromatogram, but the coloring of the original solution can be used to make up for the shortcomings.

5. Acid and alkali resistance Polypropylene fiber has good chemical resistance. In addition to concentrated nitric acid and concentrated caustic soda, polypropylene fiber has good resistance to acids and alkalis, so it is suitable for use as filter materials and packaging materials.

6. Light resistance, etc. Polypropylene fiber has poor light resistance, poor thermal stability, easy aging, and is not resistant to ironing. But it can improve its anti-aging performance by adding anti-aging agent during spinning. In addition, polypropylene fiber has good electrical insulation, but it is easy to generate static electricity during processing.

7. High strength Polypropylene stretch yarn is second only to nylon in strength, but the price is only 1/3 of that of nylon; the fabric made of it has stable dimensions, good abrasion resistance and good chemical stability. However, it has poor thermal stability, is not resistant to sunlight, and is prone to aging and brittle damage. For this reason, anti-aging agents are often added to polypropylene.