1991 Volume 17 Issue 1 Pages 29-34
Two kinds of heat-stable antibacterial clay interlayer compounds were prepared by exchanging Na-montmorillonite with cationic ammine complexes of silver and copper. The one contained only silver ions, the other silver and copper ions. The extent of elution of Ag+ from the former antibacterial clay was dependent on the ligand. For the latter, the amount of Ag+ eluted was decreased markedly by adding copper ammine complex. However, it was possible to control the extent of elution of Ag+ by changing the loading amount of copper ammine complex. When the antibacterial clay was mixed with plastics, the concentration of Ag+ eluted from the resultant plastics was also dependent on the kind of antibacterial clay. The antibacterial effect for Staphylococcus aureus was observed by mixing only 1 wt% of the clay with plastics. For Bacillus subtilis, though the antibacterial clay having only Ag+ was effective by mixing its 1 wt%, more than 3wt% was necessary for the clay having Ag+ and Cu2+ cations. The toxicity test using mice and rats was found to be negative, indicating that the toxicity of the antibacterial clay was negligible.
