Conductive rubber member
View Patent ↗The present invention provides a conductive rubber member which exhibits low electrical resistance, and has properties that are less affected by environmental factors, and excellent staining resistance. The conductive rubber member of the present invention has a base rubber predominantly containing epichlorohydrin rubber, and a conductive elastic layer which is formed, through hardening and molding of a rubber composition, wherein the rubber composition contains, as vulcanizing agents, a thiourea-type vulcanizing agent and a thiuram-type vulcanizing agent, and contains no elemental sulfur.
1. A conductive rubber member having a conductive elastic layer which is formed through molding and hardening of a rubber composition,
wherein the rubber composition contains a base rubber comprising epichlorohydrin rubber and as vulcanizing agents, a thiourea-type vulcanizing agent and at least one member selected from the group consisting of thiuram-type vulcanizing agents and dithiocarbamate-type vulcanizing agents, and contains neither elemental sulfur nor any conductivity-imparting agent, and
the conductive elastic layer has an electrical resistance, as measured under application of a voltage of 100 V and NN conditions (25° C., 50% RH), falling within a range of 5.0×10 4 to 5.0×10 7 Ω.
2. The conductive rubber member according to claim 1 , wherein the rubber composition contains no conductivity-imparting agent, and the conductive elastic layer is characterized in that an absolute value of the difference between a common logarithm of electrical resistance (Ω) as measured under LL conditions (10° C., 30% RH) and that of electrical resistance (Ω) as measured under NN conditions (35° C., 85% RH) is 1.5 or less, the electrical resistance being measured under application of a voltage of 100 V.
3. The conductive rubber member according to claim 1 , wherein the epichlorohydrin rubber is a copolymer formed from epichlorohydrin and at least one member selected from the group consisting of alkylene oxides and allyl glycidyl ether.
4. The conductive rubber member according to claim 1 , wherein the conductive elastic layer has a surface portion assuming in the form of a surface-treated layer formed through impregnating a surface of the conductive elastic layer with a surface-treatment liquid containing at least an isocyanate component and an organic solvent.
5. The conductive rubber member according to claim 4 , wherein the surface-treatment liquid further contains at least one member selected from the group consisting of carbon black, an acrylic fluoropolymer, and an acrylic silicone polymer.
6. The conductive rubber member according to claim 1 , which has a roller shape, a blade shape, or a belt shape.