SEMICONDUCTIVE RUBBER RAW MATERIAL COMPOSITION, METHOD FOR MANUFACTURING SEMICONDUCTIVE RUBBER RAW MATERIAL COMPOSITION AND SEMICONDUCTIVE SEAMLESS BELT

摘要

PROBLEM TO BE SOLVED: To provide a semiconductive rubber raw material composition for an electrophotographic device rubber member which regulates fluctuations in the specific volume resistivity based on the fluctuation in the kneading lot of a semiconductive rubber member within one digit, a method for manufactur ing the same and a semiconductive seamless belt. SOLUTION: This semiconductive rubber raw material composition is prepared by adding silica powder composed of particles of <=30μm in average grain size of primary aggregate at 1 to 30 pts.wt. to 100 pts.wt. rubber material and the specific volume resistivity R (Ω.cm) of its rubber after the vulcanization is semiconductive of 107 to 1012Ω.cm. The desired semiconductive rubber raw material composition is obtained by using the basic raw material rubber composition having the specific volume resistivity R0 after vulcanization satisfying logR0<0.5 (logRmax+logRmin) and adding the silica powder of the amount to attain logR=0.5 (logRmax+logRmin) in accordance with the change rate of the specific volume resistivity based on the previously determined amount of addition to the basic raw material rubber composition and kneading the mixture.