Question

What is the use of finding more kinds of microfibres and regenerated fibres.

Answer 1

Microfibers

Microfiber is defined as a staple fiber or filaments of linear density approximately 1 dtex or less, and above 0.3 dtex. Although acrylic, viscose and polypropylene are available for the production of microfibers, polyester and polyamide are the main source. The fabrics made from them can be 100% microfiber or in blends with wool, cotton or viscose. Microfibers are half the diameter of a fine silk fiber, one-third the diameter of cotton, one-quarter the diameter of fine wool, and one hundred times finer than human hair. In order to be classified as a microfiber, the fiber must be less than 1 dtex in width. Fabrics made of microfibers are generally lightweight, resist wrinkling, have a luxurious drape on the body, retain shape, and resist pilling. They are also relatively strong and durable in relation to other fabrics of similar weight, and they are more breathable and more comfortable to wear. Fabrics made of microfibers show lower heat conductance and therefore higher thermal insulation properties. Microfiber fibers exhibit a warmer feeling than conventional fabrics depending on pressure, which may be due to the difference in the fiber and fabric surface in contact with the human skin (Schacher et al., 2000; Purane and Panigrahi, 2007).

The first ‘micro-denier’ products were introduced by Japanese fiber manufacturing companies during the 1970s. The production of microfibersfollowed in Europe during the 1980s and since the 1990s by American manufacturers. Toray was the first company in the world to introduce microfibers, followed by Teijin, Hoechst, ICI, DuPont, and others. Recently Toray has introduced an ultra-fine polyester microfiber with a linear density of filament of about 0.05 dtex. This may be called the finest synthetic fiber so far produced commercially. At present, polyester and nylon are generally used for manufacturing microfibers. However, ‘micro-denier’ versions of rayon and acrylic products are on the horizon.

Three conventional spinning methods, i.e. melt spinning, dry spinning, and wet spinning can be used to manufacture microfibers. However for producing microfibers by these methods, the polymerization process, polymer spinning and drawing conditions have to be selected and executed very carefully. The technology involved in the extrusion of microfibersis more sophisticated and costly than that of conventional deniers as microfibers are delicate products that require great attention in handling during textile mill processing.

Microfiber spinning is now possible by many major fiber producers on their existing equipment, however economical production of high quality microfibers will require significant changes in future machine design and operation. Generally speaking, there are two techniques to produce microfibers:

•

direct spinning (conventional POY spinning), and

•

bi-component process (segment and island-in-sea type).

Different procedures have been presented and employed to produce microfibers:

1.

Dissolved type

2.

Split type

3.

Direct spun type

4.

Super-drawing technique

5.

Sheath-core spinning method

6.

Flash-spinning method

7.

Solution flash-spinning

8.

Emulsion-spinning method

9.

Jet-spinning method

10.

Centrifugal-spinning method

11.

Turbulent forming method

12.

Conjugate-spinning method.

In the early development of microfibers, researchers were interested in finding suitable fields of application as the microfibers had properties which had not existed in previous clothing and technical textile concepts.