1. Dept of Applied Chemistry, University of Osaka Prefecture Mozu–Umemachi, Sakai, Osaka 591, Japan
2. Materials Research Dept, Central Research Institute Taiyou Yuden Co., Ltd, Haruna–Machi, Gunma–gun, Gunma 370–33, Japan
3. Laboratory of Leather Technology, Osaka Prefectural Industrial Research Institute, Kishibe Naka, Suite 564, Japan