Expanded-graphite sheet
AssigneeToyo Tanso Co., Ltd.
InventorYoshiaki Hirose
Life of this patent
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Abstract
An expanded-graphite sheet whose thermal conductivity in its surfacewise directions is relatively uniform and higher than its thermal conductivity in its perpendicular direction can be produced efficiently at relatively low cost. Because the expanded-graphite sheet is made of expanded graphite alone and has thermal conductivity in parallel direction of 350 W/(m·K) or more, its thermal conductivity in parallel direction is much higher than its thermal conductivity in a perpendicular direction; therefore, it is suitable for the conduction and diffusion of heat. Besides, the expanded-graphite sheet can be produced easily, in a short time, efficiently, at relatively low cost.
Claims23
An expanded-graphite sheet consisting of a single sheet of expanded-graphite, wherein a thermal conductivity of the expanded-graphite sheet is 350 W/(m·K) or more in a direction parallel to the surface of the expanded-graphite sheet, said expanded-graphite sheet having an arithmetic mean surface roughness of less than 5 μm.
An expanded-graphite sheet consisting of a single sheet of expanded-graphite, wherein a thermal conductivity of the expanded-graphite sheet is 350 W/(m·K) or more in a direction parallel to the surface of the expanded-graphite sheet, and wherein the difference between the highest and lowest values of local thermal conductivities at various spots on the expanded-graphite sheet is 10% or less of the overall mean thermal conductivity thereof.
An expanded-graphite sheet made by a process comprising:
- (i) compressing a single sheet of expanded graphite into a single crude sheet;
- and
- (ii) compressing the single crude sheet, with a rolling mill operating at a rolling speed of less than 3 m/min, into the expanded-graphite sheet, the expanded-graphite sheet having a thickness of 0.05-1.5 mm, a bulk density of 1.6-2.1 Mg/m3, and a thermal conductivity of 350 W/(m·K) or more in a direction parallel to the surface of the expanded-graphite sheet.
An expanded-graphite sheet consisting of:
- expanded-graphite;
- and
- optionally an impurity content,
- wherein a thermal conductivity of the expanded-graphite sheet is 350 W/(m·K) or more in a direction parallel to the surface of the expanded-graphite sheet, said expanded-graphite sheet having an arithmetic mean surface roughness of less than 5 μm.
An expanded-graphite sheet consisting of:
- expanded-graphite;
- and
- optionally an impurity content,
- wherein a thermal conductivity of the expanded-graphite sheet is 350 W/(m·K) or more in a direction parallel to the surface of the expanded-graphite sheet, and
- the difference between the highest and lowest values of local thermal conductivities at various spots on the expanded-graphite sheet is 10% or less of the overall mean thermal conductivity thereof.
Dependencies are inferred from the claim text.