Fiber is a natural or synthetic substance that is significantly longer than it is wide.Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate fibers, for example carbon fiber and ultra high molecular weight polyethylene.The fiber came to success when the researchers obtained a product (polymerized amide, from which the name polyamide) by condensation of molecules presenting two reactive aminic groups (hexamethylenediamine) with molecules characterized by two carboxylic reactive groups (adipic acid).
In order to be differentiated from other polymers belonging to the same chemical class, this polymer was marked with the acronym 6.6 which indicates the number of carbon atoms (that is 6) in the two molecules forming the repetitive polymer unit.
Polyester fiber
This is the most important man-made fiber, with a production of 22 million tons in 2003 (58% continuous filament/42% staple fiber), which since some years overcame cotton production. The number of plants installed in the world is estimated already now at more than 500.
Another aspect of considerable importance under the geographic-economic point of view is the fact that 75% of the production is located in Asia. Polyester wrung the record of most produced synthetic fiber out from the polyamide fiber already in 1972 when it reached a share of 65% in the synthetic fiber market. Its success is due to its particular characteristics, to its versatility in the various application sectors and to the relatively low raw materials and production costs.
Polyamide fiber
This fiber category practically opened the textile market to fibers with no connection to the world of nature.
The production, performed worldwide by about 300 plants, amounts to 3,9 million tons (2003) and is distributed into polyamide type 6 (about 60%) and polyamide type 6.6 (about 40%); it is composed mainly of the continuous filament (85%), against 15% of staple fiber. The major producing countries are still Europe and USA (45% of the market).
Acrylic fiber
The production of this fiber is estimated at 2,6 million tons (2003) and West Europe is still today the area with the highest production (30%).This fiber found its main use in the traditional wool sectors and is being produced in practice only in form of discontinuous or staple fiber.
