JPS63434Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is a heat insulating material that reduces radiant heat transfer.In particular, when insulating the space between the inner and outer tanks by creating a vacuum, there is The present invention relates to a heat insulating material that is suitable for use as a support material for vacuum heat insulation and has excellent heat insulating performance.

In general, when forming a heat insulating layer, heat transfer factors such as solid conduction heat transfer, air conduction and convection heat transfer, and radiation heat transfer of hot wires intervening in the heat insulating layer that contribute to heat transfer are reduced. considered as such. Conduction heat transfer in solids is dealt with by using a so-called heat insulating material with low conductivity, and conduction and convection heat transfer in air is dealt with by eliminating the air present in the heat insulating layer to be formed and creating a vacuum space. Furthermore, radiant heat transfer is dealt with by using a metal foil or the like with a glossy surface for the heat insulating layer to reflect and block incoming heat rays. As a heat insulation method that takes into consideration the above requirements, a powder insulation material such as perlite or silica airgel is mixed with powder or pieces of a shiny metal, such as aluminum, and filled between the inner and outer tanks, and the space between the inner and outer tanks is evacuated. There is a method to create a heat insulating space. However, with this method, uniform dispersion is difficult due to the difference in density between the powder insulation material and the metal powder or small pieces, resulting in uneven packing density in the insulation space, and this deviation becomes even more pronounced due to vibrations, etc. . Therefore, the heat insulating effect becomes unstable and has the disadvantage of impairing the heat insulating performance. Another example is a method in which a molded insulating material made of an organic material such as plastic foam is used, and a shiny metal foil such as aluminum is interposed between the insulating materials to form a layer and fill the space between the inner and outer tanks. There is. However, with this method, the strength of the molded product is weak, and when applying vacuum insulation, it is difficult to support the vacuum load applied to the inner and outer tanks.In addition, since it is an organic material, organic gas is released during the vacuum evacuation operation, and the vacuum I had a problem holding it.

For this reason, we focused on the fact that calcium silicate molded bodies, which have been conventionally used as heat insulating materials, are inorganic materials with continuous open pores and have low thermal conductivity and high strength. When used as a support material for vacuum insulation, a layer of shiny metal powder for blocking radiant heat transfer is interposed between the calcium silicate molded bodies in a layered state in an extremely closely bonded state to form an integral structure, In addition to the heat insulation factors of calcium silicate's inherent porosity and low thermal conductivity, it also has a radiant heat shielding function, and has extremely improved heat insulation performance, making it suitable for use as a support material for vacuum insulation. It is a material.

Hereinafter, an example of the heat insulating material of the present invention will be explained with reference to the drawings. In Fig. 1, 1a, 1b, and 1c are calcium silicate molded bodies, which are obtained by mixing silicic acid raw materials, lime raw materials, and water, and performing a hydrothermal reaction under high temperature and high pressure in an autoclave. It has a continuous open pore structure obtained by adding an inorganic fiber material as a reinforcing agent, compression molding it, and then drying it. 2 is a paint containing metal powder with a glossy surface, preferably metal powder such as aluminum, stainless steel, tin, or copper. The heat insulating material M of the present invention includes the calcium silicate 1a and 1
The metal powder-containing paint layer 2 is interposed between b, 1b and 1c to form an integral structure by closely bonding them in a layered manner.In the present invention, calcium silicate is A hardened layer 3 is formed by impregnating each bonding surface portion of 1a, 1b, and 1c with an aqueous solution of silica sol, alumina sol, ethyl silicate, or an alkali metal silicate such as sodium silicate or potassium silicate.
The formed hardened layer 3 sufficiently retains the continuous open pore structure that is a characteristic of the calcium silicate molded body, and is hard enough to provide a surface that allows the metal powder-containing paint 2 to be spread to a uniform thin thickness. form a layer.

Next, the paint 2 mixed with metal powder is uniformly dispersed in the hardened layer 3 and developed into a thin layer, but as described above, the calcium silicate molded bodies 1a, 1b, 1
Since the bonding surface has been hardened, it is very easy to apply the metal powder-containing paint 2 to form the desired uniformity and thin layer.

Next, the calcium silicate molded bodies 1a, 1b, and 1c with the metal powder-containing paint 2 applied to the hardened layer 3 are laminated, pressure-bonded, and dried, with the metal powder-containing paint 2 interposed therein. As shown, a heat insulating material M having an integral structure in which a plurality of calcium silicate molded bodies 1a, 1b, and 1c are tightly and firmly laminated and bonded by interposing the metal powder-containing paint 2 is obtained.

The heat insulating material M of the present invention obtained as described above
Because the joint surface of the calcium silicate molded body is hardened, it is possible to apply metal powder-containing paint to the joint of the calcium silicate molded body extremely uniformly and in a thin layer. The layered bonding of the molded body, metal powder layer, and calcium silicate molded body is achieved extremely tightly and firmly, forming an integral structure with enhanced strength. Moreover, it maintains the lightweight, continuous open pore structure, low thermal conductivity, and compressive strength inherent to calcium silicate molded bodies, which reduces the conductivity of the solid, which is an insulating factor, and allows air layer conduction and convection. In addition to meeting the necessary conditions such as creating a wide vacuum space to reduce heat transfer, it also has a radiant heat blocking function, which further improves insulation performance, making it extremely effective as a support material for vacuum insulation. At the same time, it also exhibits excellent effects as a heat insulating material with the function of blocking radiant heat transfer even under normal pressure. Furthermore, it is extremely easy to process and always maintains a good heat insulating function without deformation over time or displacement of the metal powder layer for blocking radiant heat.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the assembly of the heat insulating material of the present invention, and FIG. 2 is an explanatory diagram of the heat insulating material of the present invention. 1a, 1b, 1c are calcium silicate molded bodies, 2
3 is a paint containing metal powder, and 3 is a hardened layer.

Claims (1)

[Scope of utility model registration request] A plurality of calcium silicate molded bodies whose surfaces have been hardened with any one of silica sol, alumina sol, ethyl silicate, and alkali metal silicate are adhesively laminated by applying paint containing metal powder with metallic luster. Features insulation material.