TEXTILE TECHNOLOGY

Cross section of nano nylon

ADVERTISEMENT How to advertise here

TIn the pursuit of the ultimate fineness of fiber, Toray Industries, Inc. has created a new technology to obtain "nano- filaments" in the multi-filament shape consisting of filaments in nano-meter (one billionth meter) orders with the double-digit smaller diameter of filaments than conventional ultrafine microfilaments (the diameter of single filament being in several micron orders).

By combining Toray's specialty fiber forming technology with nano- structure controlling technology, Toray has developed this new technology and achieved the ultimate fineness, which extensions of conventional technology were unable to attain. This is an excellent technology in general-purpose properties. This technology is applicable to general polymers such as nylon and polyester, and allows utilizing conventional equipment in manufacturing.

By utilizing this technology, Toray has successfully developed, for the first time in the world, nylon nano-filament yarn (44dtex) consisting of more than 1.4 million filaments with a diameter of 20- 100 nano-meters. These nano-filaments develop special functions which the surface of filaments has in possession because of their extremely large surface area, compared with conventional fibers. Consequently, there is an expectation for the development of new materials, which were not available so far. Toray has already applied for a patent covering this technology and expects to obtain a fundamental patent.

In 1968, Toray created high molecular orientation by means of a sea-- island bicomponent-spinning technology. Toray has developed this technology to produce diversified products characterized by ultrafine microfilaments such as suede-type man-made leather, wiping cloth and high precision filter cloth. With the emergence of ultrafine microfilaments born from this high molecular orientation, the diameter of the filament reached micron orders (1,000 nano- meters). So far, however, conventional ultrafine microfilaments technology was not able to spin uniformly fine yarn on the nano order level at the spinning stage. By controlling the structure of polymer molecular orientation on the nano level and by optimizing the fluidity of polymer itself, Toray has for the first time successfully developed nylon nano-filaments with a uniform diameter in dozens of nano-meters.

Another fiber with the diameter of fiber on the nano-meter level is carbon nano tube. It is known that it can exhibit new special properties such as unique electron releasing performance as well as hydrogen absorbing and storing property resulting from the nano structure elaborately designed than in the case of regular carbon fiber. Likewise, in the case of the newly developed fiber using versatile polymer, the development of unique functions resulting from the nano structure is hopeful. Specifically, in addition to the properties of the bulk of polymer which conventional fibers have in possession, the contribution of special properties offered by the surface of fiber with higher activity than on the inside of fiber will become extremely great. Consequently, the emergence of new functions such as adsorbing property and adhesive properties as well as the development of new materials so far unavailable are hopeful.

The availability of nano-fiber in the filament shape by this new technology will make easy not only processing into various products, but also the control of orientation and they shape of the nano- filaments. So it is expected that the application of this new technology to diversified sectors will accelerate

Despite being 100% nylon in composition, moisture-absorbing property improved two to three times higher than conventional nylon filaments and moisture-- absorbing property equal to or higher than that of cotton is obtainable in the case of the newly developed nano- filaments, for example. In the case of conventional nylon filaments, the volume of moisture absorption on the surface of filaments was nearly 1/1,000 of the moisture absorption volume on the inside of filaments. Therefore, the volume of moisture absorption on the surface of filaments was negligible. Nevertheless, the surface area of the newly developed nano-filaments is about 1,000 times against conventional filaments. So for the first time Toray was successful in the manifestation of moisture-- absorbing effects on the surface to a great extent.

For the future, Toray will carry out basic studies applicable not only to versatile polymers such as polyester and polypropylene, but also on new materials such as polylactic acid. At the same time, the firm plans to develop new products with new functions by combining the newly developed nano-filaments with advanced processing technology.

By extensively utilizing nanotechnology, Toray has worked on the research and development of new materials capable of making remarkable progress in special qualities of high molecular materials beyond extensions of conventional studies, while proposing these products to the market as major products.

Toray has also created nano-filaments based on these basic and advanced studies. The company is highly confident that nano- filaments will not only bring about new developments in the textile sector, but also create a new field in surface and interface technology.