Filmy graphite and process for producing the same
View Patent ↗A process for producing a filmy graphite includes the steps of forming a polyimide film having a birefringence of 0.12 or more and heat-treating the polyimide film at 2,400° C. or higher.
1. A filmy graphite produced by heat-treating a polyimide film having a thickness of 75 μm or more, wherein the filmy graphite has an electrical conductivity of 1.2×10 4 S/cm or more and a ratio of electrical resistance at 77 K to that at room temperature of 1.5 or less.
2. A filmy graphite having a thickness of 32.5 μm or more, an electrical conductivity of 1.2×10 4 S/cm or more, wherein the filmy graphite has a ratio of electrical resistance at 77 K to that at room temperature of 1.5 or less.
3. A filmy graphite produced by heat-treating a polyimide film having a thickness of 50 μm or more, wherein the filmy graphite has an electrical conductivity of 1.6×10 4 S/cm or more and a ratio of electrical resistance at 77 K to that at room temperature of 1.0 or less.
4. A filmy graphite having a thickness of 20 μm or more and an electrical conductivity of 1.6×10 4 S/cm or more, wherein the filmy graphite has a ratio of electrical resistance at 77 K to that at room temperature of 1.0 or less.
5. A filmy graphite produced by heat-treating a polyimide film having a thickness of 75 μm or more, wherein the filmy graphite has an electrical conductivity of 1.2×10 4 S/cm or more and a ratio of electrical resistance at 4 K to that at room temperature of 1.4 or less.
6. A filmy graphite having a thickness of 32.5 μm or more and an electrical conductivity of 1.2×10 4 S/cm or more, wherein the filmy graphite has a ratio of electrical resistance at 4 K to that at room temperature of 1.4 or less.
7. A filmy graphite produced by heat-treating a polyimide film having a thickness of 50 μm or more, wherein the filmy graphite has an electrical conductivity of 1.6×10 4 S/cm or more and a ratio of electrical resistance at 4K to that at room temperature of 0.9 or less.
8. A filmy graphite having a thickness of 20 μm or more and an electrical conductivity of 1.6×10 4 S/cm or more, wherein the filmy graphite has a ratio of electrical resistance at 4 K to that at room temperature of 0.9 or less.