31^st Application Technology Workshop for Textiles. Prof. Hamada of Shinshu University speaks on trends in dyeing technology.

Prof. Hamada giving lecture

Prof. Kunihiro Hamada from Faculty of Textile Science and Technology, Shinshu University gave a lecture under the theme, "Research trends in dyeing in the last decade (with a focus on Japan)," at the 31^st Seni Oyo Gijutsu Kenkyukai (the Application Technology Workshop for Textiles) held in Osaka on March 14. The summary of his lecture is as follows.
Research papers in relation to dyestuff and dyeing, or research papers related to dyestuff and textiles as two principals are decreasing worldwide.

However, there are conspicuous trends that research into color performance by looking at dyestuff from a new perspective, into dyeing auxiliaries and into media is increasing because of textile modifications to bring about various functional improvements and through nanofiber developments. At the same time, people in the dyestuff and pigment industry are proceeding from specific applications like textiles to expansion of functional pigments targeting a wide rage of applications.

Ink-jet printing for textiles now has a great deal of potential in different usages from those of conventional printing. The application range will spread. In Shinshu University, we are pursuing research on ink color removal to seek new utility value in ink-jet printing. To ascertain the effect, we carried out an experiment to check the effective color degradation of reactive dye ink. In the experiment, color discharge printing by ink-jet was carried out to discharge the color without ruining the design. We used an aqueous reducing agent first, but now we are proceeding to the next examination considering the durability of the ink heads.

<Future dye wastewater technology will focus on decomposition of chemical substances>

We may look at the recent moves of an increasing volume of research into dye wastewater through the perspective of decomposition of chemical substances like dyestuff. Most has been about the introduction of wastewater treatment so far, but recently research on decomposition of dyestuff is starting to be introduced in related literature. Research into decomposition behavior of dyestuff in solution is increasing as well.

More and more research into decomposition with sodium hypochlorite, decomposition with the combination of hydrogen peroxide and enzyme, or ultrasonic sound or ultraviolet, ozone decomposition, photocatalytic decomposition using oxidized titanium, microorganism decomposition and decomposition by supercritical water oxidation has been made recently, and it shows this will become important in future wastewater treatment. More research in those areas will continue to be carried out in the future.

Various methods for 3D printing to be realized in Japan.
Spurring technological competition.

3D expressive printing technology has entered the competitive age in Japan. A characteristic of this technology is to express 3D representations with special designs. Matsuo Nassen in Japan has successfully achieved lace-stitch-style printing, and received an increasing number of orders. By discharging a white, fine-line pattern from a black-dyed ground color, lace-stitch-style can be expressed. An elegant flower pattern is printed over it. The printing method is rotary screen printing using pigments. Other than Matsuo Nassen, there is a printing firm carrying out 3D expressive printing with 3D expressive designs and a high-mesh flat screen made of stainless steel provided by a screen frame manufacturer in the Kansai area. This method can allow printing fine lines first in white, in contrast to Matsuo Nassen's technology, to express 3D lace-stitch-style.

Unitika develops water-based and transparent antistatic coating agent.

Unitika has developed a water-based antistatic coating agent "elitel/alow base SAS series," which has high transparency and excellent water resistance, being capable of forming a layer with strong adhesiveness on a base material, by using newly developed tin oxide sol (described below). "elitel/alow base SAS series" has 4 items of elitel SAS-U8135, elitel SAS-U8135-OT, alow base SAS-U81SB and alow base SAS-U81TB, and it is targeting sales of 200 million yen for the first year and 1 billion yen for the third year for the antistatic coating of various resin films, synthetic papers and glass.

Unitika presented the following five points as characteristics of "elitel/alow base SAS series."

1. Use environment-independent antistatic property
   It shows excellent antistatic property which is 108Ω/□　surface resistance value even under 20% RH, being humidity-independent.
2. Good transparency
   The coating is transparent and colorless, so does not affect the haze value after being applied to transparent film.
3. Good adhesiveness to wide range of base materials
   It can be applied to PET film, PP film and Ny film, and various other base materials such as metal, paper and glass through selections of binder resin.
4. Surfactant-free uncontaminating property
   Because no surfactant is used for this series (except for SAS-U8135-OT), bleeding of low-molecular substances which contaminates base materials does not occur.
5. Environment- friendly water-based coating
   Solvent consists largely of water, and is fully prepared for environmental issues.
   

▼Tin oxide sol "AS series"
According to Unitika's announcement, tin oxide sol "AS series" is a sol made with Unitika's unique technology to disperse ultrafine particles of stannic oxide into water, and has the following excellent characteristics.

1. Wide range in density of solid content
   Around 5-20 wt% concentrations of stannic oxide are available.
2. Excellent stability
   Sol is very stable and almost no temporal changes can be seen.
3. Good transparency
   The coating is transparent and colorless, so does not affect the haze value after being applied to transparent film.
4. Use environment-independent antistatic property
   It shows excellent antistatic property which is 108Ω/□ surface resistance value even under 20% RH, being humidity-independent.

Asahi Kasei Fibers promotes "Sunplay" 2007 swimwear material.
For chemical recycling, quick-dry, UV protection and see-through infrared ray prevention.

Asahi Kasei Fibers will mainly promote four functional materials based on consumer buying patterns and various needs for its 2007 swimwear material "Sunplay," which are chemical recycling, quick-dry, UV protection and see-through infrared ray blocking. It will suggest other two materials, chlorine resistant spandex "Roica SP" to protect swimwear from the chlorine in the water of a pool and soft and stretch PPT fiber "Solotex"* as stretch material which is essential for swimwear. Asahi Kasei Fibers is preparing a system for production of swimwear for 2007 to provide swimwear fabrics made with "Roica" and the company's differentiated material from Hangzhou Asahi Kasei Textiles (Zhejiang, China).

(Note) * "Solotex" is a trademark of SOLOTEX Corporation, a joint venture company of Asahi Kasei Fibers and Teijin Fibers.