JPH07103640A - Heat insulating box body - Google Patents

Abstract

PURPOSE:To provide a heat insulating box body which is designed to provide specified heat insulating performance as the increase of the thickness of a heat insulating material is suppressed even when a foaming agent having a boiling point higher than a specified temperature is used. CONSTITUTION:A heat insulating box body 1 comprises an outer box the 2, an inner box 3, and a heat insulating material 4 located in the space between the two boxes 2 and 3. The heat insulating material 4 forms two-layer structure of a foamed heat insulating material 7 filled with a foaming agent having a boiling point higher than +40 deg.C and a vacuum heat insulating material 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat insulating box body provided with a heat insulating material in a space between an outer box and an inner box.

[0002]

2. Description of the Related Art Conventionally, a heat insulating box constituting a refrigerator, a low temperature showcase or the like has a space between an outer box and an inner box as disclosed in Japanese Patent Publication No. 3-25713 (F25D23 / 08). It is formed by injecting an undiluted solution of a heat insulating material from the inlet and foaming and filling. In this case, the stock solution of the heat insulating material comprises a polyol component and an isocyanate component, and both components are reacted in the presence of a foaming agent, a reaction catalyst, and a foam stabilizer to obtain a rigid polyurethane foam.

In general, a rigid polyurethane foam heat insulating material having closed cells has excellent heat insulating properties with high productivity, and therefore has extremely low gas thermal conductivity as the above-mentioned foaming agent, and also has low boiling point, nonflammability, and low toxicity. For example, trichloromonofluoromethane (R-11) having excellent properties has been commonly used (see JP-A-62-81414).

[0004]

However, the above blowing agent, trichloromonofluoromethane (R-11), is used.
Is a persistent CFC (Chloro Fluoro Ca)
It is said that when this kind of persistent CFC is released into the atmosphere, it adversely affects the ozone layer in the stratosphere and raises the surface temperature due to the greenhouse effect, which has become a global environmental pollution problem in recent years. However, there is an increasing trend to regulate the production and consumption of these persistent CFCs.

Therefore, a foaming technique using cyclopentane (C5 H10), which is not restricted by the above regulations, as a foaming agent has been researched. However, the boiling point of cyclopentane is extremely high at + 50 ° C. and is usually -20 ° C. In the portion close to the inner box to be cooled below, cyclopentane is completely condensed in the cell of the rigid polyurethane foam in which the cyclopentane is enclosed. When cyclopentane is condensed in the cells of the foam, the thermal conductivity of the rigid polyurethane foam becomes extremely high as compared with that in the gas state, so that the heat insulation performance thereof is significantly deteriorated. Therefore, in order to obtain the required heat insulation performance, the thickness of the heat insulating material (rigid polyurethane foam) must be increased as a result, which reduces the internal volume of the heat insulating box or expands the installation space of the box. I had a problem coming.

The present invention was made in order to solve the above-mentioned conventional technical problems, and suppresses the expansion of the thickness of the heat insulating material even when a foaming agent having a high boiling point of + 40 ° C. or higher is used. It is an object of the present invention to provide a heat insulating box body that can obtain a required heat insulating performance.

[0007]

That is, the heat-insulating box body 1 according to the invention of claim 1 comprises an outer box 2, an inner box 3, and a heat insulating material 4 provided in a space between both boxes 2, 3. The heat insulating material 4 has a multilayer structure of a foamed heat insulating material 7 filled with a foaming agent having a boiling point of + 40 ° C. or more and a vacuum heat insulating material 6.

Further, the heat insulating box body 1 according to a second aspect of the present invention is such that the vacuum heat insulating material 6 is attached to the outer box 2 and the foam heat insulating material 7 is filled into the inner box 3 side of the vacuum heat insulating material 6. Is.

Further, the heat-insulating box body 1 according to the invention of claim 3 comprises an outer box 2, an inner box 3, and a foamed heat insulating material 10 filled in a space between both boxes 2, 3. , Foam insulation 1
0 is the first foam insulation material 11 filled in the outer box 2 side with a foaming agent having a boiling point of + 40 ° C. or higher and the second foam insulation material 11 filled in the inner box 3 side with a low boiling point foaming agent. The foamed heat insulating material 12 has a multilayer structure.

Furthermore, the heat insulating box 1 of the invention of claim 4 is the above invention, wherein cyclopentane is used as the foaming agent having a boiling point of + 40 ° C. or higher.

[0011]

According to the heat-insulating box body 1 of the invention of claim 1, the heat-insulating material 4 provided between the inner and outer boxes 3 and 2 is filled with a foaming agent having a boiling point of + 40 ° C. or more such as cyclopentane. Since the heat insulating material 7 and the vacuum heat insulating material 6 having a very high heat insulating performance at a lower temperature than the foam heat insulating material 7 have a multi-layered structure, the inner box 3 is different from the case where only the foam heat insulating material 7 is provided. When the temperature becomes low, the heat insulating performance of the heat insulating material 4 as a whole is improved. Therefore, the heat insulating material 4 is more than the case using only the foam heat insulating material 7.
It becomes possible to obtain the required heat insulation performance while reducing the overall thickness.

Further, according to the heat insulating box body 1 of the invention of claim 2, in the above, the vacuum heat insulating material 6 is attached to the outer box 2 and the foam heat insulating material 7 is filled in the inner box 3 side of the vacuum heat insulating material 6. Therefore, the work of attaching the vacuum heat insulating material 6 is facilitated, and the risk of the vacuum heat insulating material 6 being damaged by various devices attached to the inner box 3 side is eliminated.

Further, according to the heat insulation box body 1 of the invention of claim 3, the foam heat insulation material 10 filled between the inner and outer boxes 3 and 2 is formed by using a foaming agent having a boiling point of + 40 ° C. or more such as cyclopentane. Since the first foamed heat insulating material 11 formed on the outer box 2 side and the second foamed heat insulating material 12 formed on the inner box 3 side using a low boiling point foaming agent have a multilayer structure, The second foamed heat insulating material 12 can maintain the required heat insulating performance even when the inner box 3 has a low temperature. In addition, the second foam insulation material 12 is the inner box 3
Since the first foamed heat insulating material 11 is thermally insulated from the above, condensation of the foaming agent in the first foamed heat insulating material 11 can also be prevented or suppressed. In general, as compared with the case where only the first foamed heat insulating material 11 is used, the heat insulating performance of the heat insulating material 10 as a whole when the temperature of the inner box 3 becomes low is improved, and the thickness of the heat insulating material 10 is reduced as a whole. It will be possible to obtain the heat insulation performance of.

[0014]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a plan sectional view of a heat insulating box 1 of the present invention. The heat-insulating box 1 of the embodiment constitutes a household refrigerator-freezer, and FIG. 1 shows a plane cross section of the freezer compartment F. The heat-insulating box 1 of the present invention includes an outer box 2 made of a steel plate having an opening on the front side, and an inner box made of a hard synthetic resin such as ABS resin having the same opening on the front side, which is incorporated in the outer box 2 with a space. It is composed of a box 3 and a heat insulating material 4 provided between the boxes 2 and 3.

The heat insulating material 4 has a two-layer structure of a vacuum heat insulating material 6 and a foam heat insulating material 7. The vacuum heat insulating material 6 is formed by vacuum-packing a powdery inorganic substance into a plate having a predetermined thickness, and has extremely high heat insulating performance against low temperatures. Prior to being filled with the foamed heat insulating material 7, the vacuum heat insulating material 6 is preliminarily attached by a double-sided tape or the like over substantially the entire inner surface of each of the upper, lower, left, and right walls of the outer box 2.

On the other hand, the foamed heat insulating material 7 is mainly composed of polyether polyol and polyisocyanate, and as the foaming agent, cyclopentane (C5 H10) which is not regulated is used. When filling the foamed heat insulating material 7 as described above, the vacuum heat insulating material 6 is attached to the inner surface of the outer box 2 as described above,
The one in which is incorporated is set in a foam mold (not shown). Then, the polyether polyol is diluted with a blowing agent of cyclopentane to form a resin, and the undiluted solution obtained by mixing the resin and the solution of the polyisocyanate in a predetermined ratio is injected from an injection port (not shown) to the outer box 2 (vacuum) by a high pressure foaming machine. It is discharged into the space between the heat insulating material 6) and the inner box 3.

The polyether polyol and polyisocyanate in the injected undiluted solution start a reaction to form polyurethane, and the heat of reaction causes gasification of cyclopentane to be contained in the foam. On the other hand, the polyurethane foam expands and fills the space between the inner and outer boxes 3 and 2, and is adhered and solidified to the vacuum heat insulating material 6 and the inner surface of the outer box 2 and the outer surface of the inner box 7 to thereby hard polyurethane. A foam insulation 7 of foam is formed.

In the heat-insulating box 1 having such a structure, the freezer compartment F
When the inside is cooled to, for example, −20 ° C. or lower, the foamed heat insulating material 7 in contact with the inner box 3 is also cooled to near −20 ° C. On the other hand, since the boiling point of cyclopentane in the foamed heat insulating material 7 is + 50 ° C. as described above, the inner box 3 having a low temperature such as −20 ° C.
The cyclopentane in the side foam insulation 7 condenses.

When cyclopentane gasified in the foam cell of the foam insulation 7 is condensed, its thermal conductivity is remarkably increased, but the foam insulation 7 at a predetermined distance from the inner box 3 is still Since heat insulation is provided by the foam heat insulating material 7 between the space and the inner box 3, the condensation phenomenon of cyclopentane is stopped and the predetermined heat insulating performance is maintained. Further, since the vacuum heat insulating material 6 is attached to the inner surface of the outer box 2, compared with the case where only the foam heat insulating material 7 is used, the inner box 3
When the temperature becomes low, the heat insulating performance of the heat insulating material 4 as a whole is significantly improved. Therefore, it becomes possible to obtain the required heat insulating performance while reducing the thickness of the whole heat insulating material 4 as compared with the case where only the foam heat insulating material 7 is used, and to expand the internal space of the freezing compartment F or the like, or the heat insulating box body. It is possible to reduce the installation space of 1.

It is to be noted that, regardless of the embodiment, the vacuum heat insulating material 6 ... Can be attached to the outer surface of the inner box 3 and the foam heat insulating material 7 can be filled in the outer box 2 side, and the outer surface of the inner box 3 and the outer box. A vacuum heat insulating material 6 may be attached to the inner surface of 2 and the foam heat insulating material 7 may be filled between them to form a three-layer structure. In that case, foam insulation 7
Is insulated from the inner box 3 by the vacuum heat insulating material 6 ...
It can be expected that the condensation of cyclopentane is prevented or suppressed, and the heat insulating performance of the heat insulating material 4 as a whole is further improved.

However, since the shape of the inner box 3 is usually complicated, not only the work of attaching the vacuum heat insulating material 6 becomes difficult, but also various devices are attached to the inner box 3 later, so that such devices are attached. There is a great risk that the vacuum heat insulating material 6 will be damaged by the screws and the like, and the heat insulating performance will deteriorate. On the other hand, the inner surface of the outer box 6 is flatter than that of the inner box 3, the vacuum heat insulating material 6 is attached to the outer box 2 as in the embodiment, and the foam heat insulating material 7 is provided between the vacuum heat insulating material 6 and the inner box 3. Is filled, it becomes easy to attach the vacuum heat insulating material 6, and
There is also no risk of the vacuum heat insulating material 6 being damaged by various devices attached to the inner box 3.

Next, FIG. 2 shows another heat insulating box 1 of the present invention. In this case as well, the heat insulating box 1 includes an outer box 2 made of a steel plate that is open to the front side, and an inner box made of a hard synthetic resin such as ABS resin that is also opened in the outer box 2 and is also open to the front side. It is composed of a box 3 and a foamed heat insulating material 10 provided between the boxes 2 and 3.

The foam heat insulating material 10 has a two-layer structure of a first foam heat insulating material 11 and a second foam heat insulating material 12. The second foamed heat insulating material 12 contains polyether polyol and polyisocyanate as main components, and water is used as a foaming agent. Then, the polyether polyol is diluted with water to form a resin, and a stock solution in which the resin and the polyisocyanate solution are mixed at a predetermined ratio is sprayed around the inner box 3 by a high-pressure foaming machine.

The polyether polyol and polyisocyanate in the sprayed stock solution start a reaction to form polyurethane, and at the same time, the polyisocyanate and water react to generate carbon dioxide gas, which is contained in the foam. On the other hand, the polyurethane foam expands and adheres to the outer surface of the inner box 3 to be solidified, whereby the second foamed heat insulating material 12 made of hard polyurethane foam having a predetermined thickness is formed.

On the other hand, the first foamed heat insulating material 11 is mainly composed of polyether polyol and polyisocyanate, and the cyclopentane is used as a foaming agent.
When filling the first foamed heat insulating material 11 as described above, the second foamed heat insulating material 12 is formed on the outer surface of the inner box 3 as described above, and the inner box 2 is assembled into a foam type not shown. set. Then, the polyether polyol is diluted with a blowing agent of cyclopentane to form a resin, and the undiluted solution obtained by mixing the resin and the solution of the polyisocyanate in a predetermined ratio is injected from an injection port (not shown) to the outer box 2 and It is discharged into the space between the two foam insulation materials 12.

Polyether polyol and polyisocyanate in the injected stock solution start a reaction to form polyurethane, and cyclopentane is gasified by the heat of reaction and enclosed in the foam, whereby the polyurethane foam expands. To fill the space between the outer box 3 and the second foamed heat insulating material 12 and adhere to the inner surface of the outer box 2 and the outer surface of the second foamed heat insulating material 12 to be solidified, whereby the first rigid polyurethane foam The foamed heat insulating material 11 is formed.

In the heat-insulating box 1 having such a structure, the freezer compartment F
When the inside is cooled to, for example, −20 ° C. or lower, the second foamed heat insulating material 12 in contact with the inner box 3 is also cooled to near −20 ° C. On the other hand, since the boiling point of carbon dioxide gas in the second foamed heat insulating material 12 is extremely low (−200 ° C.), the carbon dioxide gas in the second foamed heat insulating material 12 is condensed even at a low temperature such as −20 ° C. However, the prescribed heat insulation performance is maintained.

On the other hand, cyclopentane in the first foamed heat insulating material 11 has a high boiling point (+ 50 ° C.) as described above, but since it is insulated by the second foamed heat insulating material 12, condensation of cyclopentane is prevented or suppressed. To be done. Therefore, as compared with the case where only the first foamed heat insulating material 11 is used, the heat insulation performance of the foamed heat insulating material 10 as a whole when the inner box 3 is at a low temperature is significantly improved. It becomes possible to obtain the required heat insulation performance while reducing the thickness of the foamed heat insulating material 10 as compared with the above case, and to expand the internal space of the freezer compartment F or the like or reduce the installation space of the heat insulating box 1. Can be achieved.

Although the heat insulating material 10 has a two-layer structure of the first foamed heat insulating material 11 and the second foamed heat insulating material 12 in the embodiment,
By forming a layer of the second foamed heat insulating material 12 in the first foamed heat insulating material 11 or the like, a multilayer structure may be used. Further, in the embodiment, the second foamed heat insulating material 12 is foamed with carbon dioxide gas, but the invention is not limited to this, and any foaming agent having a low boiling point that is hard to condense even when cooled from the inner box 3 may be used. Difluoromethane (R-2
2) or a mixture of R-22 and 1-chloro-1,1-difluoroethane (R-142b), or R-134
a, etc. are also conceivable. However, if water is used as the foaming agent as in the examples, complete dechlorofluorocarbon can be achieved.

Further, although cyclopentane was used as the foaming agent in the above foamed heat insulating material 7 and the first foamed heat insulating material 11, in addition to this, HFC (H
Hydro Fluorocarbon, which is not regulated) and HFC + hetoro compounds are also effective.

[0031]

As described in detail above, according to the invention of claim 1, the heat insulating material provided between the inner and outer boxes is filled with a foaming agent having a boiling point of + 40 ° C. or more, and a vacuum heat insulating material. Since the material has a multi-layered structure, the heat insulating performance of the entire heat insulating material is significantly improved when the inner box has a low temperature, as compared with the case where only the foam heat insulating material is used. Therefore, it becomes possible to obtain the required heat insulating performance while reducing the thickness of the whole heat insulating material as compared with the case of using only the foam heat insulating material, thereby expanding the internal volume of the heat insulating box, or the heat insulating box. The installation space can be reduced.

Further, according to the invention of claim 2, in the above, the vacuum heat insulating material is attached to the outer box, and the foam heat insulating material is filled in the inner box side of the vacuum heat insulating material. The installation work is easy, the vacuum insulation is usually protected by the outer box made of metal, and there is little risk of breaking the vacuum, and the risk of damage to the vacuum insulation by various equipment installed on the inner box side. Disappears.

Further, according to the third aspect of the present invention, the foam insulation material filled between the inner and outer boxes is filled with the foaming agent having a boiling point of + 40 ° C. or more on the outer box side to form the first foam insulation material. Also, since it has a multi-layered structure of the second foam insulation material filled in the inner box side by using the low boiling point foaming agent, the second box is used even when the inner box becomes low temperature (for example, freezing temperature). The foam insulation of can maintain the required insulation performance, and since the second foam insulation insulates the first foam insulation from the inner box, condensation of the foaming agent in the first foam insulation is also prevented, Alternatively, it can be suppressed. In general, compared with the case where only the first foam insulation material is used, the insulation performance of the insulation material as a whole when the temperature of the inner box becomes low is significantly improved, and the required insulation performance is reduced while reducing the thickness of the insulation material as a whole. As a result, it is possible to expand the internal volume of the heat insulating box or reduce the installation space of the heat insulating box.

Furthermore, when cyclopentane is used as the foaming agent having a high boiling point as in the invention of claim 4, it is possible to provide a heat-insulating box body that contributes to environmental protection without using regulated CFCs. is there.

[Brief description of drawings]

FIG. 1 is a plan sectional view of a heat insulation box of the present invention.

FIG. 2 is a plan sectional view of another heat insulating box body of the present invention.

[Explanation of symbols]

 1 Insulation Box Body 2 Outer Box 3 Inner Box 4 Insulation Material 6 Vacuum Insulation Material 7 Foam Insulation Material 10 Foam Insulation Material 11 First Foam Insulation Material 12 Second Foam Insulation Material

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area // C08L 101: 00

Claims (4)

[Claims] 1. A heat insulating box body comprising an outer box, an inner box, and a heat insulating material provided in a space between both boxes, wherein the heat insulating material is filled with a foaming agent having a boiling point of + 40 ° C. or higher. A heat insulating box body having a multi-layered structure of a foam heat insulating material and a vacuum heat insulating material. 2. The heat-insulating box body according to claim 1, wherein a vacuum heat insulating material is attached to the outer box, and a foam heat insulating material is filled on the inner box side of the vacuum heat insulating material. 3. A heat insulating box body comprising an outer box, an inner box, and a foam heat insulating material filled in a space between both boxes, wherein the foam heat insulating material is formed by using a foaming agent having a boiling point of + 40 ° C. or more. A heat-insulating box body having a multilayer structure of a first foam heat insulating material filled in the outer box side and a second foam heat insulating material filled in the inner box side by using a low boiling point foaming agent. . 4. The heat insulating box according to claim 1, wherein the foaming agent having a boiling point of + 40 ° C. or higher is cyclopentane.