| 摘要 |
PROBLEM TO BE SOLVED: To provide a cylindrical vacuum heat insulation material having high heat insulation performance.SOLUTION: The vacuum heat insulation material is formed by stacking a plurality of fiber sheets whose ease of bending varies between the perpendicular directions in a plane with the directions of greater ease of bending being aligned to make a plate-like core material, by vacuum-sealing the core material in a packing material and by curving it so that the direction in which the ease of bending of the fiber sheet is larger is made a circumferential direction of the cylindrical surface. The difference in ease of bending is provided by controlling the making speed or the production speed by a melt spinning method of the fiber sheet. The insertion of a film with a small friction coefficient between the inner circumferential surface of the core material and the packing material is proposed. |
