Japanese companies have introduced three intriguing specialty fabric products that combine once-incompatible features.
By Kikuko Tagawa
Cool Cargo helps save lives in Africa
Cool Cargo FZ,” collaboratively developed and produced by Twinbird and Taiyo Kogyo, and the 2007 Award of Excellence winner in the industrial applications category of IFAI’s International Achievement Awards, is a refrigerated container developed to transport and store frozen items. It can maintain an inner temperature of –20°C while the outside temperature is 40°C, and holds up to 100 liters.
Dr. Naoyuki Kawahara, working in the Sudan, sent an e-mail to Twinbird Corp. (Niigata-ken, Japan) and to Taiyo Kogyo Corp. (Osaka, Japan), thanking the companies for the refrigerator they have developed. He wrote, “It has been so hot here—up to 40°C and sometimes 50°C this summer. We were able to save a boy who was having a convulsive seizure, due to a snake bite, by giving him blood serum stored in the refrigerator … It has also been so useful for storing the drug for malaria testing. I just wanted you to know this and how thankful we are.”
Powered by a 12-volt battery, Cool Cargo is particularly useful in areas where the electric power supply is insufficient. At Dr. Kawahara’s clinic, a solar power system on the roof is the clinic’s only power source. The Cool Cargo unit stores medicines that must be refrigerated, such as the live cholera vaccine and antitoxic serums administered in cases of poisoning.
Cool Cargo also combines portability with heat insulation; it’s light enough to be lifted by one adult. In ordinary refrigeration equipment, including home refrigerators, heat insulation materials are covered by steel plates. Cool Cargo FZ uses the new technology of vacuum insulation panels: The panels are wrapped in an aluminum-deposited sheet, which is machine sewn, to be exceptionally lightweight. The latest type of Stirling cooler unit contributes to Cool Cargo’s portability. Another Cool Cargo product, 200N/200L, can be folded to a compact size, yet holds up to 200 liters.
Mr. Yuji Emura of Taiyo Kogyo says that Cool Cargo was “developed from studying architectural membrane materials whose properties include light weight, heat insulation, heat shielding, and cold insulation … Cool Cargo is used by restaurants for catering. We have also received an order from the military. Because it can be operated using a 12-volt battery, mounting it on an ordinary vehicle turns the vehicle into a freezer van. That means food distributors do not have to purchase a special vehicle, which translates to greater cost savings in frozen food distribution. Also, it can be mounted right next to other products. One vehicle can carry frozen products, refrigerated items and room-temperature items at the same time with no problem.”
Photocatalysts at work
Cleaning the surfaces of fabric structures, tents and awnings has always been a headache. But 10 years ago, those headaches became a thing of the past.
Taiyo Kogyo Corp. and Nippon Soda Corp. Ltd., Tokyo, Japan, debuted the photocatalyst-treated fabric for architectural applications, based on the TOTO (Fukuoka, Japan) patent in 1998. (For more details, see “Light + Bright fabrics” in the January 2005 Review.) Titanium dioxide (Ti02) oxidizes and decomposes organic matter attached to surfaces. When applying the Ti02 photocatalyst technology to fabric, the major challenge was how to coat on the PVC (an organic material) with the photocatalyst, because photocatalysts break down not only bacteria and dirt but also PVC itself. Nippon Soda developed the technology for an undercoat and middle layer between the PVC and the TiO2 layers; the middle layer separates as well as adheres the two other layers. Because of the hydrophilic properties of photocatalysts, rain easily washes away dirt. The material also has an oxidative decomposition effect on air pollutants (NOx and SOx in the surrounding environment) as well as on organic matter on the fabric surface.
Another new photocatalyst technology, developed by Kanbo Pras Corp., Osaka, Japan, is Dynastar®. A photocatalytic-treated PVC architectural membrane, Dynastar was released to the market in September 2007.
“Dynastar is a fabric coated by titanium dioxide at the surface of the PVC/polyester fabrics,” explains Mr. Yutaka Sumida of Kanbo Pras. A self-renewing system, it “removes the dirt and soil on the fabric surface by decomposing the fabric itself with the photocatalytic reaction of sunlight and the natural action of rain and wind. It may sound a little harsh to decompose the fabric itself, but the surface that decomposes is very thin, only about one micron a year.”
Fabric producers note that Dynastar, unlike traditional photocatalytic fabrics, can be welded either by RF welding or by hot air. “It is much easier to manufacture,” says Mr. Sumida. “It has been very popular; it is developing a good reputation with clients. Also, we are now applying this technology to glass fiber fabrics and will be releasing that soon.”
Fabric structure manufacturers around the world are now benefiting from photocatalytic technogies … and so are the users of these structures.
Liner provides advantages for Bird’s Nest roof
The inner liner roof of the Beijing Olympics main stadium, the “Bird’s Nest,” is composed of high-performance architectural membrane material, specially developed for the stadium from the Skytop® line. Skytop is PTFE-coated glass fiber B yarn fabric by Chukoh Chemical Industry Corp. Ltd., Tokyo, Japan. Although Skytop has been used in projects such as the Tokyo Dome, Bangkok’s new Suvarnabhumi Airport, soccer stadiums and schools, meeting the requirements for the Bird’s Nest was a new challenge for the company.
“The client required the inner liner to have high translucency,” says Chukoh president Mr. Naoyuki Shono. “At the same time, the liner needed high tensile strength and high sound absorption. Those were conflicting requirements.” Property requirements for the liner were as follows: translucency of more than 30 percent, a central value sound absorption coefficient (NRC) of 57 percent, and tensile strength of more than 2000 N/3 cm warp and 1500 N/3 cm weft.
Working behind–and above—the scenes at the Bird’s Nest, the roof’s Skytop membrane contributed to the visual splendor of the 2008 Olympic Games, and will continue to benefit athletes and spectators for years to come.