Vol.9 No.3 2017

Research paper : Development of HASClay® as a high-performance adsorption material (M. Suzuki et al.)−161−Synthesiology - English edition Vol.9 No.3 (2017) phase separation occurred when heating was done at 120 ºC or higher, and imogolite would not be produced.[17] This taboo was broken by one question from an assistant staff who said, “What happens when HASClay GIII is heated at high temperature?” At that time, the project was almost over and we had time on our hands, so we went ahead to actually see the phase separation phenomenon, but this led to the discovery of a new substance. We thought it was important not to blindly accept what we had experienced thus far, and to listen to and not reject the ideas of novices. However, over one year passed after the discovery of HASClay GIII before we discovered HASClay GI.4 Scenario after the development of adsorbents4.1 Role of AIST in the initial product realizationAlthough it became possible to develop excellent adsorbents, for industrial mass synthesis, we decided to go ahead with the commercialization of HASClay GIII product since its synthesis method was simple.The investigation of desiccant rotors that was our primary objective was done using the new material HASClay GIII through joint research with a company that wished to fabricate a desiccant rotor using imogolite. About 1 kg of powder was synthesized without any problem, and good results were obtained in the papermaking test. In the next stage, we shifted to the fabrication of the rotor by actual full papermaking, and the amount necessary was 40 kg of powder. In addition to the fact that we were not sure that the synthesizing company would accept this request, we expected that about half a year was necessary, and therefore, the synthesis was conducted at AIST. Although it was already confirmed that the synthesis of 1 kg per batch was possible, the time needed for washing after heating synthesis was a hurdle. This was solved by the suihi method (washing method where the HASClay and a large amount of water are mixed and then left to stand, and the water is separated from HASClay that settles at the bottom of the container by gravity). Our great gain was that we learned the necessary tricks for HASClay synthesis by repeating the procedure for large-volume synthesis. Ultimately, we synthesized 40 kg of materials three times in about eight months. As a result, it seemed that good performance of a desiccant rotor could be obtained, and when we asked the company that had handled imogolite synthesis before, it willingly agreed to synthesize HASClay. This was before the press release, but it was important that the company which would conduct the synthesis and the company which would use the product were starting to take action.The fact that a company was at a preparatory stage of synthesizing and supplying HASClay was an extremely important factor in doing the press release later.The development of the desiccant rotor was conducted in the following framework: AIST developed the synthesis method of the material with excellent adsorbent/desorbent capacities; the synthesis company developed the mass synthesis method that enabled synthesis in tons and adjusted particle grinding to create suitable particle distribution for fabricating the desiccant rotor; and the desiccant rotor manufacturing company fabricated the high-performance rotor using the HASClay precursor that was supplied by the synthesis company.4.2 Development for the expansion of usageInitially, the development of HASClay was conducted as development of adsorbents for desiccant air conditioning, but other uses were considered since it showed excellent adsorption of water vapor.In the evaluation for humidity controlling building material, it was demonstrated that when the interior finishing material containing HASClay and gypsum was used, the power consumption of air conditioning was reduced.[18] The demonstration test at the Experimental Building for Environment-Friendly Building Materials of AIST Chubu is shown in Fig. 12. In the evaluation of this humidity controlling building material, there were very few cases where the evaluation of the humidity controlling performance was done for the entire room instead of a test piece at a research lab level. It is important that the evaluation be done in the form close to actual use, and we had great advantage 0102030405060708090020406080100)G()G()G()G()G()G()Adsorption volume (wt%)Relative humidity (%): HASClay GI (adsorption): HASClay GI (desorption): HASClay GII (adsorption): HASClay GII (desorption): HASClay GIII (adsorption): HASClay GIII (desorption)0010202030404050606070808090100Fig. 11 Water vapor adsorption isothermal curves of HASClay

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