| 摘要 |
PROBLEM TO BE SOLVED: To provide a rubber member for electrophotographic use, the member having resilience remaining satisfactorily stable over changes in environmental conditions. SOLUTION: The rubber member is a rubber elastic material, comprising polyurethane which is obtained by using a long-chain polyol and comprising a polyester polyol having 500 to 5,000 number average molecular weight and 6 to 8 mmol/g ester concentration defined by Formula (1): concentration of ester(mmol/g)=(number of moles of ester group)/(weight of polyester polyol), polyisocyanate, and a short-chain polyol having <500 molecular weight, wherein the long-chain polyol essentially comprises polyester polyol prepared by condensation of at least either 1,9-nonanediol or methyl-1,8-octanediol with adipic acid. The material has≤55% forΔRb expressed by Formula (2):ΔRb(%)=Rb<SB>T50</SB>-Rb<SB>T10</SB>, wherein Rb<SB>T10</SB>and Rb<SB>T50</SB>represent the resilience of the rubber elastic material at 10°C and 50°C, respectively. The rubber elastic material has≥15% resilience at 10°C, and≤70% resilience at 50°C. COPYRIGHT: (C)2005,JPO&NCIPI
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