초록 ▼

A vacuum heat insulator according to the present invention includes a core molded to be plate-shaped with the use of a binding agent. The vacuum heat insulator assumes any one of the following configurations. A) The core is formed by curing a fiber aggregate by means of a binding agent. The fibers

A vacuum heat insulator according to the present invention includes a core molded to be plate-shaped with the use of a binding agent. The vacuum heat insulator assumes any one of the following configurations. A) The core is formed by curing a fiber aggregate by means of a binding agent. The fibers have an average fiber diameter of at least 0.1 μm but at most 10 μm, and voids defined by fibers have a void diameter of at most 40 μm. The core has a percentage of the voids of at least 80%. B) The binding agent is varied in concentration in a through-thickness direction of the core. C) A cured layer solidified by the binding agent is formed on at least one side surface of the core. D) The core contains fibers having a length of at most 100 μm. The fibers are oriented perpendicular to a direction of heat transmission. Such vacuum heat insulator is excellent in adiabatic property. Refrigerators, to which such a vacuum heat insulator is applied, are made small in size, or have a large inner volume, or contribute to energy saving.

대표청구항 ▼

The invention claimed is: 1. A vacuum heat insulator comprising: a molded plate-shaped core having an aggregate comprising fibers and a binding agent for curing the fiber aggregate, and an exterior cover enclosing the core in a chamber defined by the exterior cover, the chamber having a pressure lo

The invention claimed is: 1. A vacuum heat insulator comprising: a molded plate-shaped core having an aggregate comprising fibers and a binding agent for curing the fiber aggregate, and an exterior cover enclosing the core in a chamber defined by the exterior cover, the chamber having a pressure lower than a pressure outside the chamber, wherein the fibers have an average fiber diameter between 0.1 μm and 10 μm, voids defined by the fibers have a void diameter of at most 40 μm, the core comprises at least 90% said voids defined by the fibers, and a difference in thickness of the core between when the core is subjected to the pressure outside the chamber and when the core is subjected to the pressure inside the chamber is at most 10%. 2. A vacuum heat insulator, comprising: a core comprising a plate-shaped molded body containing fibers and a binding agent, the concentration of the binding agent being larger at a surface of the core than inside the core in a through-thickness direction thereof, thereby decreasing a solid thermal conductivity of the core, decreasing resistance to exhaustion, and ensuring a strength of the vacuum heat insulator; and an exterior cover enclosing the core in a chamber defined by the exterior cover, an interior of the chamber having a lower pressure than an exterior of the chamber, the exterior cover having a groove that extrudes toward a center of the core. 3. The vacuum heat insulator according to claim 1, wherein the binding agent contains at least an organic binder. 4. The vacuum heat insulator according to claim 1, wherein the binding agent contains at least an inorganic binder. 5. The vacuum heat insulator according to claim 1, wherein the binding agent contains at least a thermosetting binder. 6. The vacuum heat insulator according to claim 1, wherein the binding agent contains at least one of boric acid, borate, phosphoric acid, phosphate, and a heated product thereof. 7. The vacuum heat insulator according to claim 1, wherein the core has a density of between at least 100 kg/m3 and not more than 400 kg/m3. 8. The vacuum heat insulator according to claim 1, wherein the fibers are made of an inorganic material. 9. The vacuum heat insulator according to claim 1, wherein the fibers contain at least one of glass wool and glass fibers. 10. The vacuum heat insulator according to claim 1, wherein the fibers constitute a nonwoven web. 11. The vacuum heat insulator according to claim 1, wherein the core includes a laminate. 12. The vacuum heat insulator according to claim 1, having a thermal conductivity of between at least 0.0015 W/mK and not more than 0.0025 W/mK. 13. A method of manufacturing a vacuum heat insulator according to claim 1, the method comprising steps of: A) covering the core with the exterior cover, B) reducing the pressure within the chamber so that the core is decreased in thickness by, at most, 10%, and C) sealing an opening of the exterior cover. 14. The method of manufacturing a vacuum heat insulator, according to claim 13, wherein the fibers are made of an inorganic material. 15. A heat insulating element comprising: the vacuum heat insulator according to claim 1, a second heat insulator other than the vacuum heat insulator, and a second exterior cover, wherein the vacuum heat insulator and the second heat insulator are located within the second exterior cover, and the second heat insulator occupies space within the second exterior cover that is not occupied by the vacuum heat insulator. 16. The heat insulating element according to claim 15, wherein the second heat insulator is a foamy heat insulator. 17. An adiabatic box, wherein the heat insulating element according to claim 15 is formed to be box-shaped. 18. An adiabatic door comprising the heat insulating element according to claim 15. 19. A storage shed comprising: the adiabatic box according to claim 17, and an adiabatic door to cover an opening of the adiabatic box. 20. A storage shed comprising: the heat insulating element according to claim 15, and an adiabatic wall for thermal insulation of an interior of the storage shed. 21. A storage shed having an adiabatic partition plate including the heat insulating element according to claim 15, wherein an interior of the storage shed is compartmented into a plurality of rooms. 22. A refrigerator comprising: the storage shed according to claim 19, and a cooling device to cool a storage room in the storage shed. 23. The adiabatic box according to claim 17, wherein the core of the vacuum heat insulator has a cured layer on at least one side surface thereof, said cured layer being solidified by a binding agent; and a surface of the vacuum heat insulator on a side of the cured layer faces an inner surface of the second exterior cover. 24. The refrigerator according to claim 22, wherein the binding agent has a higher concentration on a surface of the core than inside the core in a through-thickness direction thereof, and said exterior cover has a groove extending from an outer surface of the exterior cover toward a center of the core, said groove for receiving a projection on a surface on which the vacuum heat insulator is located. 25. The refrigerator according to claim 24, wherein the cooling device includes a refrigerant pipe and the projection is the refrigerant pipe. 26. The refrigerator according to claim 22, further comprising an adhesive to fix the vacuum heat insulator to the second exterior cover. 27. The refrigerator according to claim 26, wherein the adhesive is a hot-melt adhesive. 28. The refrigerator according to claim 26, wherein the adhesive has a thickness of between at least 70 μm and not more than 130 μm. 29. A method of manufacturing a refrigerator, the method comprising: a) manufacturing a vacuum heat insulator by the method according to claim 13, b) enclosing the vacuum heat insulator and a second heat insulator that is not the vacuum heat insulator within a second exterior cover to form a heat insulating element, c) forming a storage shed from at least one of adiabatic boxes, adiabatic doors, and adiabatic walls by using the heat insulating element, and d) mounting a cooling device that cools an interior of the storage shed. 30. A refrigerator comprising: the storage shed according to claim 20, and a cooling device to cool a storage room in the storage shed. 31. A refrigerator comprising: the storage shed according to claim 21, and a cooling device to cool a storage room in the storage shed. 32. The refrigerator according to claim 22, wherein the core of the vacuum heat insulator has a cured layer on at least one side surface thereof, said cured layer being solidified by a binding agent; and said exterior cover comprises a groove extending from an exterior surface of the exterior cover toward a center of the core.