Textile polypropylene fibers fundamentals

Polypropylene (PP) fibers contain, according to ISO 2076, minimally an 85% portion of macromolecular polypropylene chains and maximally 15% of another fiber-forming polymer, the content of nonfiber-forming substance being unlimited. Of the stereoregular isomers, only isotactic PP is used for fiber preparation. Nowadays, new types of PP (s)mdio-tactic, metallocene based) have been developed for fiber and film production. The first industrial company that launched the production of PP fibers was Montecatini Co. (1959), then after 1960 l.C.l., Celanese, Hercules, etc. Japanese companies started the production of bicomponent fibers. Ciurently, the global production amounts to 4200 kt of PP fibers in wide assortment of textile, industrial and special typ es. Table 1 presents a survey of the world production of PP fibers in 1992-1995. 

The diameter of fiber or the surface of the cross-section are generally expressed in term of linear density or titre (T) of the fiber in tex units (10 kgm ) respectively in derived units ktex, dtex, mtex. One tex means that a fiber 1000 m long has the weight of 1 g. The expression 7 dt = 167 dtex X/ 32 X 2, for example, means that it is a multifilament 167 g/10 000 m with 32 monofilaments multiplied by two. The individual titre Tj = 167 32 = 5.2 dtex. PP fibers can be divided into four basic groups according to technology and the use [1-3]  

mono- and multifilaments. Monofilaments are infinite individual fibers with the linear density of Tj s 150 dtex and higher multifilaments are infinite fibers formed by a certain number of monofibers  

spunbonded types. T 2-15 dtex and melt-blown color Tj 0.01-10 dtex for nonwoven materials. 

fibers and tapes from films. Fibrillated or cut 10-200dtex and melt-blown technology from films Tj over 50 000 dtex. 

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