Vacuum thermal-insulatng material and its mfg. method

Abstract

Provided is a vacuum heat insulating material, using inorganic fibers as a core material, high in heat insulating performance (low in thermal conductivity), capable of maintaining the heat insulating performance for a long period, free of defects such as projections and depressions on a large scale on a surface thereof, short in manufacturing time and advantageous in terms of cost; and a manufacturing method therefor. A vacuum heat insulating material of the present invention is of a construction in which a core material (1) and a gas adsorbent (2) are housed in a bag (3) made from a gas barrier film and the interior thereof is reduced in internal pressure thereof and air-tightly sealed, wherein the core material 1 is a molded product obtained by coating a binder B on inorganic fibers having an average fiber diameter in the range of from 3 to 5 mum at a coating amount in the range of from 0.5 to 1.5 wt % relative to the fibers and heat pressing the inorganic fibers, or a laminate fabricated by stacking two or more sheets of the molded product.

Description

technical field [0001] The present invention relates to a vacuum heat insulating material using inorganic fiber as a core material and a manufacturing method thereof. Background technique [0002] As the core material of the vacuum heat insulating material in which the core material is housed in a bag made of a gas barrier film to depressurize and seal the inside, conventionally known materials such as polyurethane foam, inorganic fiber, and inorganic powder are used, but Among them, even when inorganic fibers are used as the core material, low thermal conductivity (high thermal insulation performance) of about 0.0025W / mk can be achieved. [0003] However, when the inorganic fiber is inserted into the bag without pretreatment and degassed under reduced pressure, there is a problem that the workability is poor, and the density must be increased to maintain the smoothness of the surface of the vacuum heat insulating material. In addition, a part of the inorganic fiber tends t...

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Problems solved by technology

[0006] However, as in Patent Document 1, even if the organic binder is thermally decomposed, it is difficult to remove all of it, and there is a problem that it takes a lot of time and cost.

In addition, as in Patent Documents 2 and 3, acid treatment requires neutralization and drying after acid treatment, requiring large-scale equipment, and furthermore, thermal insulation performance may be lowered due to heat conduction in the molten part.

Secondly, when using a reinforcing material as in Patent Document 4, warping occurs due to the difference in strength between the inorganic fiber aggregate and the reinforcing material, which seriously affects the thermal insulation performance of the reinforcing material, and may greatly impair the thermal insulation performance of the inorganic fiber alone

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