| Many kinds of functional finishes are increasingly processed in Japanese textile industries. The aim of these finishes is to produce textiles which are comfortable for the consumer. Such functional finishes to realize comfort are divided into two categories, that is “Physically based technology” and “Chemically based technology”.
Recently, the number of developments in physically based technology, which can harmonize the environment and production, have increased because regulations on chemical substances have become stricter.
At present, although chemically based technology is still major, its combination with physically based technology is steadily increasing (Figure-1).
| Figure-1 Classification of fiber surface modification technology1) |
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One example of physically based technology, which is not included in Figure-1, is the shrink proofing of wool without using chlorine. This new technology was developed first in the world by the wool department of Kurabo (Japan) and commercialized under the name of ECO-WASH 21. This technology adopts special ozone treatment instead of chlorine treatment, and was developed on the supposition that regulations on chlorine use would become globally stricter (Photo-1).
Prof．Inagaki in the Faculty of Engineering of Shizuoka Univ. (Japan)is also working on the shrink proofing of wool employing low temperature plasma2).
Prof. Takagishi in Tokyo Kasei Univ. is studying the same theme using potassium hydrogen persulfate (PMS) and Keratinase (enzyme for hydrolysis of keratin), and evaluating the dyeing behavior of the treated wool3).
| Photo-1 Comparison of the surface of wool (electron microscope) |
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The reason for the increase in such research is that strict controls have started to be imposed on the amounts used of halogens, such as fluorine, chlorine, bromine and iodine.
HBCD (hexabromocyclododecane), a flame retardant has proved to be toxic, and its use is carefully controlled.
Although the flame retardant effect of DBDE is expected to be higher by incorporating antimony trioxide, recently the generation of highly toxic dioxins has been confirmed, thus the regulation of those chemicals has become stricter. At present, flame retardants are widely applied to curtains and flags etc., and recently new flame retardants for polyester fiber based on phosphates have been developed to solve this problem.
As a topic in Japan, the generation of dioxins in the bleaching process in the pulp industry is confirmed, although the situation is different in the bleaching of cotton. Thus, in Japanese dyehouses, they check the content of AOX and halomethane in their effluent, and some are employing further treatment such as activated carbon. But it pushes the costs up so much that new technology which uses light irradiation for cotton bleaching is progressing.
The organizations who are studying this technology are Sangyo Sougo Kenkyusho (Japan) and Nisshinbo. They are making joint efforts to accelerate the research. Their work named “light bleaching” aims to make only the colored contamination absorb the light and activate it then to react with rather mild chemicals to decompose the color at room temperature4).
The special feature of this method is that the cellulose itself can be bleached with almost no damage. For bulk production, a new pilot plant was installed, and tests for commercialization have been continuing. We are expecting successful results for light irradiation bleaching based on physical technology, because the state of bleached cotton influences the effectiveness of functional finishing.
The above-mentioned research is the ultimate example of “the harmonization of the environment and production” although research along that course is also increasing. The research forwards the establishment of ultimate new technology can be helpful indeed, in the establishment of that new technology.
Reference
1)K.Joukou: presented in the discussion at Japan Dyers’ Association meeting
2-4)From the annual meeting of The Society of Fiber Science and Technology, Japan 2005 |