JP2000320958A - Vacuum heat insulating body and heat insulating structural body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat insulating structural body restricting the deterioration of heat insulating performance due to the heat of surface of the outer cell, such as an outer casing for a refrigerator or the like, by the thermal crosslinkage of a vacuum heat insulating panel arranged in the outer casing and reduced in the deformation of an appearance. SOLUTION: A heat insulating structural body is constituted so as to have a vacuum heat insulating body, having a thickness D whose ratio to the length L2 of an end side part or the ratio L2/D is not less than 2.0, while the ratio of the same to the length L1 of the short side of a surface part or the ration L1/D is not less than 20 and arranged in the outer cell, and remaining air gap is filled with porous bodies comprising independent bubbles. In this case, the end side part of the vacuum heat insulating body is positioned in the outer cell at a corner whereat the end side part is intersected with the wall surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum heat insulator used as a heat insulating material in a heat insulating box of a refrigerator, and more particularly to a vacuum heat insulator for achieving an improvement in heat insulating performance and a vacuum heat insulator using the same. Heat insulation structure.

[0002]

2. Description of the Related Art Conventionally, the wall surface of a heat insulating structure such as a refrigerator or an insulated car has an outer shell made of a thin metal plate such as an iron plate, an inner shell made of a resin molded product, and a porous inner space. The foaming agent for urethane foam, which is a heat insulating material, is a hydrochlorofluorocarbon (hereinafter, referred to as HCFC) containing chlorine that causes ozone layer destruction in its molecule. Instead of, 1-dichloro-1-fluoroethane, without destroying the ozone layer,
Moreover, replacement with cyclopentane, which is a hydrocarbon having a low global warming potential, is in progress.

However, the heat insulation of urethane foam using cyclopentane as a foaming agent has a thermal conductivity of 17 to 20 mW / mK, and is generally 10% or more higher than that of a conventional foaming agent using HCFC. Inferior. This means that in refrigerators, etc., which are required to reduce power consumption for the purpose of effectively utilizing energy resources without using substances that cause ozone layer depletion, the heat insulating performance of urethane foam, which is a heat insulating material, must be improved. Since it is considered to indicate that it is at the limit, as shown in the comparative diagram of FIG. 14, a technique of applying a vacuum heat insulating panel, which is a vacuum heat insulator capable of obtaining heat insulating performance more than twice that of urethane foam, has been proposed. I have.

The vacuum heat insulating panel 1 has the structure shown in FIG. 15, and since the inside is kept in a vacuum, the core material 2 has a role of preventing deformation due to atmospheric pressure and maintaining the shape.
As a result, a porous material is inserted, and the packaging material 3 suppresses invasion of gas from the outside. In other words, it is a porous material similar to foamed resin such as urethane foam, which is a conventional heat insulating material, but it eliminates gas by continuous pores to secure a vacuum state and absorbs external gas that enters over time. Since a high degree of vacuum is maintained by providing the getter agent 4, heat transfer components due to gas are eliminated, and excellent heat insulation performance is exhibited. Here, in order to achieve a further improvement in heat insulation performance, a material that does not easily transmit heat is used as a constituent material, and the amount of heat transferred between the materials is suppressed by reducing the contact area between the materials. In addition, it is effective to suppress radiant heat transfer by providing a smaller gap.

As a material satisfying such conditions, a porous material such as a resin or glass is suitably used. In particular, a resin foam board having mats of glass fibers or open cells, and molding of resin or inorganic fine particles are preferable. It is common to apply goods. For example, Japanese Unexamined Patent Publication No. Sho 60-71881 proposes a method in which pearlite powder and a pulverized PUF product in Japanese Unexamined Patent Publication No. Sho 60-243471 are put into a synthetic resin bag and vacuum-packed into a board shape. In addition to this,
No. 205164, open-cell urethane foam
A plate-shaped molded product obtained by sintering thermoplastic urethane resin powder of No. 18540, and in Japanese Patent Application Laid-Open No. Hei 7-96580, a board in which long fibers of glass are solidified and held by resin fibers obtained by fibrillating inorganic fine powder into vacuum fine insulation panels It has been proposed to be applied as a core material.

The above-mentioned vacuum heat insulating panel 1 is generally in the form of a plate having a thickness of 10 to 30 mm, and is disposed on a heat insulating wall 5 such as a heat insulating box of a refrigerator or the like in a state shown in a sectional view of FIG. Used. In other words, the vacuum insulation panel 1 is fixed to the outer box 6 formed by bending a thin metal steel plate having a design property by painting or pasting a print film with a double-sided tape or the like. The outer shell of the heat insulating box is obtained by fitting the inner box 7 obtained by shaping by a vacuum forming method or the like. If a raw material mixture of urethane foam 8 which is a heat insulating material is injected into the space formed by the outer box 6 or the vacuum heat insulating panel 1 and the inner box 7 in the outer shell to foam and fill the space, The heat insulating wall 5 in the heat insulating box of the refrigerator can be formed.

Next, a method of manufacturing a vacuum heat insulating panel will be described with reference to the process chart shown in FIG.
The core material 2 obtained by processing urethane foam having the open cells is inserted into a bag which is a packaging material 3 formed by heat sealing in advance (S-1). This is fixed in the chamber of the vacuum packaging machine 9, and the inside of the chamber is 1 * 1.
After performing “evacuation” to secure an arbitrary vacuum atmosphere of about 0 ⁻¹ to 1 * 10 ⁻³ torr (S-2), the sealing heater 11 is used to lower the fusion heater 11 to insert the insertion port. Is sealed by fusing the remaining end 12 (S-3). Finally, when the thermoplastic resin used for the end side 12 which is the insertion opening of the core material 2 cools down to the melting point or less, the vacuum inside the vacuum packaging machine 9 is released to return to normal pressure, and the vacuum insulation panel is removed. Take it out (S-4).

The packaging material 3 used here is made of, for example, polyethylene or the like, which can be heat-sealed to the inner layer used for sealing the edges, so that the surfaces are overlapped and the three edges are linear. It is obtained by heat-sealing and forming into a bag shape.

In the "vacuum evacuation" step (S-2), the packaging material in which the core material is inserted is fixed in a vacuum packaging machine, and the pressure is reduced to 1 torr or less.
Preferably, a gas such as air remaining in the pores of the core material is exhausted by forming a vacuum atmosphere of 5 * 10 ^-2 torr. The remaining gas such as air can be exhausted not only from the end of the insertion port but also from the surface of the core material through a gap provided between the packaging material and the core material, so that the degree of vacuum can be easily reached. In the subsequent "edge sealing" step (S-3), the end of the insertion opening of the core can be sealed to secure an internal vacuum.

Here, the porous body containing continuous pores used as the core material 2 includes, in addition to the above-mentioned foams such as resin,
Since the granular material has many pores which are continuous voids generated by contact between particles, it can be suitably used.
When heat transfer is schematically shown in any porous substance,
It can be expressed as a sum of four components as in Equation 1. That is,
The solid heat transfer component (λ) transmitted through the solid part of the porous body
s), a gas heat transfer component (λg) that similarly transmits the gas component,
Radiant heat transfer component (λr) due to heat ray radiation as an electromagnetic wave;
A convective component (λ) transmitted by the convective motion of the gas in the pores
c). Among them, the convection component (λc) is used to increase the ratio of the resin of the foamed resin in order to obtain a strength in which the porous substance according to the present invention does not deform with time even when subjected to atmospheric pressure. As a result of taking measures such as densely filling particles, λc may be neglected because pores of a size that does not cause convection movement of gas in the pores may be used, and as a result, It is substantially constituted by the remaining three components (λs, λg, λr).

Λ = λs + λg + λr + λc (1)

However, in the vacuum insulation panel, since the gas in the pores of the porous substance inside the vacuum insulation panel is eliminated and a vacuum state is established, the heat transfer component of the porous body containing continuous pores similar to the foamed resin is obtained. Since the heat transfer component ([lambda] g) due to one of the gases was also eliminated, a remarkably superior heat insulating performance was able to be exhibited as compared with a conventional heat insulating material such as a foamed resin.

However, the packaging material 3 of the vacuum insulation panel 1 used here has a structure as shown in FIG.
In other words, the inner layer used for sealing the side edges is made of a heat-fusible layer 13 made of a thermoplastic resin such as polyethylene or polypropylene that can be heat-sealed, and the outermost layer is made of a resin such as nylon or polyester resistant to damage. Surface layer 1
4. A gas shielding layer 1 made of a metal foil such as aluminum for completely blocking the intrusion of outside air into an intermediate layer between them.
5 is provided with a state fixed on a base material 16 which is a high-strength film such as polyethylene terephthalate, and a material constituting each layer in a sheet shape is laminated by an adhesive or welding; A multi-layer sheet 17 obtained by integration and hardly permeating a foaming agent or gas in the air is generally used.

However, the gas shielding layer 1 disposed in the multilayer sheet 17 as the packaging material 3 for the purpose of shielding gas permeation.
In 5, in consideration of handling and workability of the packaging material 2, aluminum having excellent flexibility including spreadability is deposited or a thin film is provided in a foil state. However, the thin film such as an aluminum foil used generally as a gas shielding layer 15, because it has about ¹⁰³ times as high thermal conductivity as compared with the resin sheet as other constituent materials, as its effect, the vacuum heat insulation Rather than in the thickness direction in which the heat transfer is shielded by the material, the influence of the heat transfer in the surface direction produced by the heat transfer of the substance alone has a considerable amount.

Therefore, in view of the heat transfer mechanism relating to the entire configuration of the vacuum heat insulating panel, it is not limited only by the thickness direction, which is the heat insulating direction, but is located outside the core made of a porous material, It consists of a multi-layer film with excellent gas barrier properties by suppressing the permeation of air, and by the above-mentioned packaging material that prevents various gases such as air outside the system from entering and prevents the degree of vacuum from lowering. It is important to consider the effects.

That is, in the embodiment of the vacuum heat insulating panel 1 in which the packaging material is arranged so as to wrap the core material, for example, the heat insulating outside the heat insulating wall 5 such as a refrigerator shown in FIG. From the surface of the packaging material (heat receiving surface), a thermal bridge that is a heat transfer path that passes through both ends and passes through the surface (heat radiating surface) buried inside the opposing heat insulating wall, and another heat insulating material Since the urethane foam 8 diffuses from the urethane foam 8 through the inner box 7 to the inside, it can be said that eliminating this effect is an important factor in obtaining the heat insulating wall 5 that makes full use of the characteristics of the vacuum heat insulating panel 1.

To cope with such a problem, Japanese Patent Laid-Open No.
In Japanese Patent Application Laid-Open No. 9-146993, by setting the thickness of the aluminum foil disposed on the inner layer of the packaging material 2 to 20 microns or less,
It is proposed to reduce the amount of heat transfer.

In Japanese Unexamined Patent Publication No. Hei 5-302696, as shown in FIG. 19, a gas shielding layer is provided in a gap between the heat-sealing layer 13 and the surface layer 14 at an end 12 which is a junction between the heat-receiving surface and the heat-radiating surface. By using a packaging material not provided with a certain aluminum foil 19 for any of the multilayer sheets 17b provided for bonding, it does not overlap with the other multilayer sheet 17a provided with the aluminum foil 19, thereby providing a heat transfer path. We propose a structure that can suppress the effect of thermal crosslinking by blocking.

In Japanese Patent Application Laid-Open No. 4-165282, as shown in FIG. 20, the auxiliary member 20 is provided at the end 12 on the outer periphery of the core member 3 provided inside the vacuum heat insulating panel 1 so as to be corrugated. When the inside is kept in a vacuum, the multilayer sheet 17 having a function of maintaining the vacuum forms a wavy shape along the auxiliary member 20. By this shape, the distance of the edge 12 required for the heat transmitted from the multilayer sheet 17a on the heat receiving surface of the multilayer sheet 17 to be transmitted to the multilayer sheet 17b on the other heat radiation surface becomes longer, As the distance increases, the thermal resistance increases. As a result, the amount of heat transfer can be suppressed, and the amount of heat leakage from the heat insulating wall is reduced, so that the heat insulating performance of a heat insulating structure such as a refrigerator is improved.

[0020]

However, according to the method disclosed in Japanese Patent Application Laid-Open No. 59-146993, defects such as pinholes generated in the process of spreading an aluminum foil into a thin film deteriorate gas shielding performance. It is necessary to keep the state in which no influence is exerted. In this publication, the lower limit film thickness is set to 7 microns. However, even if the lower limit film thickness is provided, if it is replaced with a resin used for a packaging material due to the relationship of thermal conductivity, it reaches about 10 mm and cannot be ignored as an effect as thermal crosslinking.

Further, the method disclosed in Japanese Patent Application Laid-Open No. 5-302696 requires extremely high precision in joining two multilayer sheets in the production of packaging materials, and cannot deal with such man-hours and techniques with versatility. Having. That is, 2
If a misalignment occurs when two multilayer sheets are joined, a portion where only the resin layer having a large gas permeability coefficient does not exist on one surface of the packaging material without the aluminum foil is opened widely. Therefore, the gas in the atmosphere easily enters from the portion where the gas shielding performance is significantly inferior, and the degree of vacuum inside the packaging material is greatly reduced in a short period of time. It creates potential.

On the other hand, in the method disclosed in Japanese Patent Application Laid-Open No. 4-165282, it is difficult to process or mold the core material because the shape of the end portion is made into a complicated waveform. Furthermore, when used as a heat insulating wall of a heat insulating structure such as a refrigerator, the heat insulating body is provided with a vacuum heat insulating panel inside an outer shell composed of an inner box and an outer box. When filling by filling the voids by injecting the raw material liquid of the foamed resin, it is not possible to completely fill even the concave recessed portion provided with the corrugated portion in the counterflow direction,
Voids remain. As a result, there is a problem that the heat insulating performance of the gap portion in the heat insulating wall is reduced.

The present invention has been made to solve the above-mentioned problems, and the heat of the outer shell surface outside the heat insulator such as the outer box of a refrigerator is provided by a vacuum heat insulating panel disposed inside the outer shell. A vacuum heat insulator capable of suppressing deterioration of heat insulation performance caused by thermal cross-linking transmitted to a packaging material having an aluminum foil with good heat conductivity in an inner layer and a heat insulation structure using the same, and the heat insulation structure having little deformation in appearance. The purpose is to get the body.

[0024]

According to a first aspect of the present invention, there is provided a vacuum heat insulator comprising a structure having continuous pores therein, wherein the vacuum heat insulator is maintained in a vacuum state. A ratio L2 of a thickness d of a surface portion composed of two opposing surfaces of the heat insulator to a length L2 of an end portion of the outer peripheral portion of the vacuum heat insulator which becomes thinner toward the outside.
/ D is 2.0 or more.

Further, in the vacuum heat insulator according to the second invention of the present invention, the ratio L2 / d of the thickness d of the vacuum heat insulation at the edge and the length L2 of the edge is 3.7 or less. It forms a shape.

Further, in the vacuum heat insulator according to the third invention of the present invention, the edge portion forms a non-linear line composed of a combination of straight lines having an arc or an obtuse angle.

Further, in the vacuum heat insulator according to the fourth invention of the present invention, the surface portion composed of the two opposing surfaces has a length L1 of the shortest side constituting the surface and a thickness d of the vacuum heat insulator.
And the ratio L1 / d is 20 or more.

According to a fifth aspect of the present invention, there is provided a heat insulating structure including a surface portion having two opposing surfaces and an edge portion having a shape in which an outward direction becomes thinner. Ratio L2 / d between the length d and the length L2 of the end portion.
Is provided in the outer shell, and the remaining voids are filled with a porous body containing independent air bubbles.

In the heat insulating structure according to the sixth aspect of the present invention, the ratio d / dt of the thickness d of the vacuum heat insulator to the thickness dt of the heat insulating material in the outer shell in which the vacuum heat insulator is disposed is equal to 0. 5 to 0.7.

In a heat insulating structure according to a seventh aspect of the present invention, the vacuum heat insulating body has an inclined end portion located in the heat insulating wall surface.

Further, according to an eighth aspect of the present invention, there is provided the heat insulating structure, wherein the vacuum heat insulator has an end portion formed at a right angle without a slope at an end thereof. It is arranged so as to be located in the outer shell at the corner where the wall intersects.

The heat insulating structure according to the ninth aspect of the present invention is characterized in that the vacuum heat insulator has a ratio L1 / d of the length L1 of the short side constituting the facing surface to the thickness d of 20 or more. It has the form which does.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 In this embodiment,
The ratio of the thickness dimension d at the end of the surface portion where the opposing surfaces of the vacuum heat insulating panel according to the present invention do not intersect to the length L2 of the end portion having a slope that is in contact with the surface portion and becomes thinner outwardly ( L2 / d) and the arrangement of the vacuum heat insulating panel on the heat insulating wall of the heat insulating structure. The cross sectional structure of the schematic diagram of FIG. The heat insulating structure to be formed will be described in detail below with reference to an explanatory diagram of FIG. 4 showing a change in the amount of heat leakage when the length L2 of the end portion is changed.

The vacuum heat insulating panel 1 of the present invention is formed by using a process diagram shown in FIG. 17 which is a conventional manufacturing method, and uses urethane foam having an interconnected cell structure as the core material 2. The inside of the wrapping material 3 of the vacuum heat insulating panel 1 having the structure as shown in FIG. 1 is maintained at a degree of vacuum of 0.02 torr. The length dimension L2 of the region is configured to be three times the thickness dimension d of the vacuum heat insulating panel at the boundary portion with the surface portion at the opposing position. Further, the heat insulating structure has two thin steel plates 21 as outer shells, the vacuum heat insulating panel 1 is fixed on one thin steel plate 21a, and the other thin steel plate 21b has a complex structure on the other thin steel plate 21b. And is integrally formed with the urethane foam 8 which is a heat insulating material.

Here, in a vacuum heat insulating panel having a thickness d of 20 mm, an aspect (L2 /
d = 0) was determined as a reference (1.0), and the ratio of the amount of heat leakage when the length L2 of the edge portion was changed to 0 to 100 mm was determined.

As shown in FIG. 1, the heat-insulating structure used here forms a plate-like sample 22 having a complexed structure with the urethane foam 8 as the other heat-insulating material in which the vacuum heat-insulating panel 1 forms the heat-insulating structure. Then, a heat flow sensor 23 (a thermocouple type manufactured by Eiko Seiki) was connected to the sample center 22a as shown in FIG.
From the sample to the sample end 22b. The vacuum heat insulating panel 1 used here has a surface portion 24 mainly used for heat reception and heat radiation, and an edge 1 in contact with the surface portion 24 and one side of an outer periphery of the vacuum heat insulation panel forms an acute angle.
The size (dimension) is such that the length of the surface portion in the direction having the inclination is 450 mm, the width of the surface portion orthogonal to it is 390 mm, and the thickness is 40 mm. The thickness of the packaging material 2 is 0.12 mm, and the thickness of the aluminum foil 19 provided at an intermediate position thereof is 0.006 mm.

The vacuum insulation panel of the above embodiment is fixed in a foaming jig so as not to be deformed by the foaming pressure of urethane foam, and is uniformly foamed on a projection surface for foam molding including the vacuum insulation panel from above. The urethane raw material mixture is dropped and sprayed, and the foaming jig is immediately closed. The urethane foam starts foaming after a few seconds, flows in this gap in a foamy state, and is filled in about 1 minute. After that, the curing of the resin constituting the urethane foam is completed in 4 to 6 minutes, and the heat insulating layer is formed. Since it is formed, by taking it out of the jig, a plate-like sample having a desired complex structure can be obtained.

Next, the amount of heat leakage was measured. Here, FIG.
26 is a sheet heater, and 27 is a Peltier type cooler, which heats and heats the upper and lower surfaces of the heat insulator facing each other.
It performs cooling. Also, a 2 mm thick aluminum plate 28a for averaging heat transfer between the heater 26 and the Peltier cooler 27 is provided above and below the sample.
7 is further provided with a 10 mm aluminum plate 28b on the cooling surface, and the heat flow sensor 23 is embedded on the surface of the plate-shaped sample 22 in order to bring the heat flow sensor 23 into close contact with the plate-shaped sample 22. A rubber plate 29 is provided.

The heat leakage amount Qt obtained by using the above apparatus and the influence of the aluminum laminated film are almost not included.
By obtaining the heat leakage amount Q2 leaking through the aluminum laminate from the heat leakage amount Q1 relating to the heat penetrating the sample center portion using the following equation 2, the degree of inclination of the end portion becomes the heat leakage amount. The effects were analyzed. As a result, the relationship between L2 / D and the amount of heat leakage is shown in FIG.

Q2 = Qt−Q1 ············································································································································································ · amount

From the results shown in FIG. 4, it can be seen that the amount of increase in the amount of heat leakage due to the influence of the thermal bridge at the edge is
In a region where the ratio L2 / d of the length dimension L2 to the thickness dimension d of the end portion is 2.8 or less, the L2 / d ratio decreases.
In other words, there was a tendency to increase sharply as the shape approaches the right angle from the acute angle. On the other hand, when the shape of the end portion of the vacuum insulation panel has L2 / d of 2.0 or more,
The amount of heat leakage is relatively small and stable, and the amount of heat leakage is relatively small.The heat leaks from the edges, that is, the heat is transmitted from the heat receiving surface to the aluminum foil placed inside the packaging material, and then to the low-temperature region through the heat dissipation surface. It has been found that the amount of heat passing through the heat path can be suppressed, and deterioration of the heat insulation performance can be suppressed.

From this result, it was found that the characteristic dimensionless length at which the amount of heat leakage did not decrease and the heat insulating performance did not deteriorate at all was 3.7. That is, L2 / d
By providing the edge portion having an acute angle shape with a ratio obtained, the increase in heat leakage can be sufficiently reduced, and the thermal insulation performance that the VIP thickness is relatively reduced by providing the acute angle shape can be offset. In some cases, it is preferable to use an end portion having an L2 / d ratio less than this.

As described above, since the edge portion of the vacuum heat insulating panel in this embodiment has an acute angle, the metal film used as one layer of the packaging material having a multilayer structure without being processed into a complicated structure. Thus, the amount of heat leakage generated due to heat conduction in the peripheral portion can be reduced, and the heat insulation performance is improved.

Further, since the shape of the heat insulator is a shape having an acute angle at the end portion, unnecessary filling of urethane foam, which is another heat insulating material of the heat insulating structure, such as disturbing the flow, is unnecessary. It creates resistance and does not hinder the filling.Also, even the edge part in the opposite direction to the flow flows along the surface of the vacuum insulation panel, so it does not create voids that are created by entrapping air . Therefore, since it is possible to completely fill the space without forming a gap between the vacuum heat insulator and the space, it is possible to prevent the heat insulation performance from being deteriorated due to poor filling, and to reduce or expand the voids such as the voids more than other parts. Therefore, it is possible to suppress the occurrence of deformation caused by the large size.

Further, the above-described shape can be realized by performing only the cutting of the end portion obliquely, so that the working is easy and the shape is simple.
Since it is possible to minimize the generation of waste material that is wasted without being used at the end in the processing of the core material, it is possible to effectively utilize the waste material.

Embodiment 2 The present embodiment relates to optimization of a ratio d / dt between a thickness d of a vacuum heat insulating panel, which is a vacuum heat insulator, and a heat insulating material distance dt in an outer shell provided with the vacuum heat insulating panel, The amount of heat leakage and d /
The optimum configuration will be described below in detail with reference to an explanatory diagram showing the relationship of the dt ratio.

The vacuum insulation panel used here is adjusted according to the thickness of the core material provided therein, and has an arbitrary thickness including a packaging material provided with a 10-micron-thick aluminum foil as a gas shielding layer. Was. Further, the degree of vacuum inside the packaging material was set to 0.02 torr, which is sufficiently higher than 0.3 torr, which is a degree of abrupt deterioration of the heat insulating performance.

Using the above-described sample and the same apparatus and method as in the first embodiment, the heat flow sensor 23 is positioned at the position shown in FIG.
Was used to measure the amount of heat leakage. The result is expressed as the amount of heat leakage when the average thickness d of the vacuum insulation panel is changed while keeping the thickness dt of the vacuum insulation structure constant.
FIG. 5 shows the relationship between the d / dt ratio and the amount of heat leakage based on the value when the / dt ratio is 0, that is, when no vacuum insulation panel is provided. According to the above results, the amount of heat leakage was minimized in the region where the d / dt ratio was 0.5 to 0.7, and the amount of heat leakage tended to increase outside the range, especially in a small region.

When the d / dt ratio is small, the amount of heat leakage increases because the amount of urethane foam having about three times the thermal conductivity of the vacuum heat insulating panel increases, and the heat insulating performance of the heat insulating structure decreases. It is based on. On the other hand, when the d / dt ratio is large, the main cause of the increase in the amount of heat leakage is that the heat insulation performance of the heat insulating structure is largely affected by the heat transfer due to the thermal crosslinking at the edge of the vacuum heat insulating panel. Things. In other words, due to the relative decrease in the thickness of the urethane foam forming the complex structure, the heat transfer from the heat receiving surface moves to the facing surface with almost no attenuation through the edge of the vacuum insulation panel. D / d
Since the distance from the heat radiating surface decreases as the t ratio increases, the attenuation of the heat transfer amount decreases, and the amount of heat transferred to the heat radiating surface increases.

As described above, in the region where the d / dt ratio is in the range of 0.5 to 0.7, it is possible to minimize the decrease in the apparent heat insulating performance due to the thermal crosslinking through the edge of the vacuum heat insulating panel. However, considering that the urethane foam, which forms the complex structure of the heat insulating structure, is injected and foamed into voids in the outer shell of the heat insulating structure other than the vacuum heat insulating panel, the vacuum heat insulating panel and the outside are considered. It is preferable to widen the gap between the shell surface and the thickness of the vacuum heat insulating panel so that the d / dt ratio is close to 0.5.

As described above, according to the present embodiment, the thickness d of the vacuum heat insulating panel and the gap d in which the vacuum heat insulating panel is disposed are described.
When the ratio (d / dt) with respect to t is 0.5 to 0.7, the amount of heat leakage at the edge portion that transfers heat through the metal film used as one layer of the packaging material having a multilayer structure In addition, by making the value close to 0.5, the filling of the urethane foam is facilitated, and the occurrence of poor filling can be suppressed, so that the effect of further improving the heat insulating performance can be exhibited.

In contrast to the arrangement of the vacuum insulation panel shown in FIG. 7-a in this embodiment, the upper and lower surfaces of the vacuum insulation panel are arranged upside down so that the contact area with the outer box is reduced. Even in a mode (FIG. 7B) that can be reduced to a small state, it is possible to suppress the decrease in apparent heat insulation performance due to thermal crosslinking through the edge portion of the vacuum heat insulation panel to the same extent.

Embodiment 3 The present embodiment relates to the effect of thermal bridges that conduct heat from the heat receiving portion of the vacuum heat insulating panel, which is a vacuum heat insulator, through the edge portion, and is less likely to be affected by the spread in the surface direction, which is the heat radiating portion of the vacuum heat insulating panel. Ratio L1 / d of thickness d and width L1 (however, width <length) of the vacuum insulation panel
Of the heat leakage and L1 / L1 shown in FIG.
This will be described in detail below with reference to an explanatory diagram showing the relationship of the d ratio. The dimension of L1 indicates the dimension in the short direction of the surface of the vacuum heat insulating panel, and is described, for example, in FIG.

The vacuum heat insulating panel obtained by the same means as in the first embodiment is fixed in a foaming jig so as not to be deformed by the foaming pressure of the urethane foam, and then a material mixture of the urethane foam is sprayed to the vacuum heat insulating panel. And urethane foam form a complexed heat insulating layer, which was taken out of the jig to obtain a plate-like sample having a desired complexed structure.

The plate-like sample 22 used here is the same as that in the first embodiment, and has a vacuum insulation different from 450 mm in width, 390 mm in length, and 10 mm to 20 mm in thickness as shown in FIG. Using a panel, heat flow was performed at intervals of 20 mm at the center in the width direction on the surface of a heat insulating structure that was a sample complexed with urethane foam so as to have a width of 500 mm, a length of 500 mm, and a thickness of 40 mm. Sensor 23
Was arranged at the position shown in FIG. 6, and the amount of heat transfer was measured. The device used here is the same as that in the first embodiment shown in FIG.

The amount of heat leakage Qt obtained by the above method and the idealized amount of heat leakage penetrating in the thickness direction of the material, which does not include the influence of the aluminum laminate film, are standardized using Equation 3 from the ideal amount of heat leakage Q1. The influence of the position in the width direction on the amount of heat leakage was obtained by obtaining the amount of leakage Q *. The position in the width direction shown here is a value obtained by dividing the position in the width direction of the vacuum insulation panel (the distance from the end of the vacuum insulation panel) by the insulation thickness d of the vacuum insulation panel. It can be shown as an agreement with the L1 / d ratio, which is the ratio to the adiabatic thickness. In addition, the amount of heat leakage shown here is the amount of heat leakage that is hardly affected by the thermal bridge transmitted through the end of the vacuum insulation panel. The heat leakage ratio Q based on Equation 3 shown in
*It was adopted.

Q * = Qt / Q1 (3)

FIG. 8 is an explanatory diagram showing the relationship between the L1 / d ratio and the amount of heat leakage. From FIG. 8, the tendency that the amount of heat leakage significantly increases due to the influence of the thermal bridge transmitted through the end of the vacuum insulation panel is that the L1 / d ratio is sharply reduced to around 10 and the L1 / d ratio decreases sharply to around 10.
If it is 0 or more, it can be almost ignored. Therefore, in order to significantly obtain the effect of improving the heat insulating performance by the vacuum insulating panel beyond the effect of the thermal bridge, it is important to include a position where the amount of heat leakage due to the thermal bridge does not excessively increase. Therefore, the width of the vacuum insulation panel is L1 / d ratio of 2
It was confirmed that it was necessary to achieve 0 or more.

As described above, the amount of heat leakage of the heat insulating structure provided with the vacuum heat insulating panel can be obtained by using the heat insulating structure having an L1 / d ratio of 20 or more, which is a ratio of the width to the thickness of the vacuum heat insulating panel. The effect of improving the apparent heat insulation performance accompanying the provision of the vacuum heat insulation panel is obtained.

Embodiment 4 The present embodiment relates to the effect of thermal crosslinking of a vacuum heat insulating panel, which is a vacuum heat insulator, and relates to the shape of an edge portion that facilitates heat transfer in the thickness direction of the vacuum heat insulating panel provided in the heat insulating structure. hand,
As an example, the configuration shown in FIG. 9 is provided, and the embodiment will be described in detail below using the form of a heat flow path provided for heat leakage shown in the explanatory view of FIG.

Using the same method as in the first embodiment, after obtaining the vacuum insulation panel 1 in which the core material having the shape shown in the sectional structural view of FIG. A plate-shaped sample 22, which is a heat-insulating structure provided with a heat-insulating layer having a complexed structure by filling urethane foam 8 in a mold in which a steel plate 21 is disposed vertically, was prepared.

The flow path of heat involving the edge 12 of the vacuum heat insulating panel 1 in the plate sample 22 will be described below with reference to FIG. Thin steel plate 21a forming the outer wall surface that is the heat receiving surface
After reaching the packaging material 3, almost no heat flow 101 flows through the core material 2 of the vacuum insulation panel 1 having a very low thermal conductivity, and most of the heat flow 101 enters the packaging material 3, especially the aluminum foil 19 inside the packaging material 3. And diffuses in the surface direction, moves to the opposite surface of the packaging material 2 on the heat receiving surface, and then reaches the urethane foam 8 which is the other heat insulating material forming the complex structure. afterwards,
Diffusion is performed from the low-temperature inner wall surface, which is the heat radiation surface, through the urethane foam 8.

At this time, since the vacuum heat insulating panel 1 used in the present embodiment is formed so as to be thin by providing a step on the end side 12 thereof, the urethane foam 8 as the other heat insulating material is relatively thin. It is formed thick. Therefore, in this portion, the amount of heat transmitted through the urethane foam 8 and reaching the inner wall surface is small, and a large amount of heat is further transmitted through the aluminum foil 19 to make the urethane foam 8 forming the outer peripheral portion thin. After reaching the surface of the vacuum insulation panel 1 buried in the urethane foam 8 facing the heat receiving surface, the urethane foam 8 penetrates through the thinned surface portion and reaches the thin steel plate 21b on the heat dissipation surface. . As described above, many heat flow paths 101 at the end portion 12 of the vacuum insulation panel take a large detour along the aluminum foil 19 and toward the vicinity of the center of the vacuum insulation panel 1 on the opposite side of the heat receiving surface. The heat conduction distance becomes longer, and as a result, the flow rate of heat decreases due to the resistance caused by flowing in the aluminum foil 19, and the amount of heat leakage, which is the amount of heat transfer, can be suppressed.

Similarly, as in the heat insulating structure shown in the sectional structural view of FIG. 11, a vacuum heat insulating panel 1 having a core material 2 having an inclined shape toward the vicinity of the center of the thickness of the vacuum heat insulating panel 1 is used. The same effect can be obtained. That is, also in the application of the vacuum heat insulating panel 1, similarly, the thickness from the thin steel plate 21a on the heat receiving surface toward the end 12 is formed relatively thin, and the urethane foam 8 as the other heat insulating material is formed. Since the heat transfer surface exists on the heat receiving surface to suppress the amount of heat transfer and the heat radiating surface is formed relatively thick, the heat flow flowing through the packaging material 3, particularly the aluminum foil 19 in the inner layer, increases the end portion 12. A detour will be taken. Therefore, the effect of increasing the heat transfer resistance with the extension of the heat flow path, reducing the amount of heat leakage, and improving the heat insulation performance can be obtained.

As described above, the thickness of the outer peripheral portion of the vacuum heat insulator at the edge portion is made smaller than the thickness of the central portion, so that the present embodiment is capable of receiving heat through a packaging material having a multilayer structure, particularly an aluminum foil. Since the main path of heat transfer from the surface to the opposite surface is provided with a large detour, the amount of heat transfer in the packaging material can be suppressed, and the effect of improving the heat insulation performance can be obtained.

Further, the core material 2 having these end portions 12 is provided.
Can be obtained without requiring complicated processing. Also,
Since the shape of the end portion 12 of the vacuum heat insulating panel 1 is continuously changed, the filling of the urethane foam 8 having a complex structure can be easily performed. In particular, since the latter core material is provided with a slope, the flow of urethane foam is facilitated and a complete filling state is easily obtained, and a decrease in heat insulation performance caused by poor filling including voids and the like is prevented. It has the effect of being able to.

Embodiment 5 In the present embodiment, a vacuum insulation panel, which is a vacuum insulation body including a right-angled edge portion, has a wall surface forming a heat insulation box of a refrigerator, which is a heat insulation structure, in order to efficiently suppress the influence of thermal crosslinking. FIG. 1 is a diagram in which an end portion forming an acute angle and an end portion forming a right angle of the vacuum heat insulating panel are disposed at respective corners so as to be located respectively.
The configuration and effect will be described below in detail using the embodiment shown in FIG.

When the vacuum heat insulating panel 1 includes a right-angled edge 30, the outer shell of the heat insulating box composed of the inner box 7 and the outer box 6 is formed to form a side plate as shown in FIG. 31
5 mm corresponding to about half of the thickness of the vacuum heat insulating panel 1 from the position where it contacts the back plate 32 so that the end portions 30 forming a right angle to the fitting portion 33 between the back plate 32 and the fitting portion 33 do not touch each other. The heat insulating wall corners 34 are arranged at the above distance, preferably within a distance of 10 mm or less, and the acute side edge portions 35 on the opposite sides are arranged on the heat insulating wall 36. The vacuum heat insulating panel 1 shown in FIG. 13 is arranged so that the edge 12 is on a line separated by a distance of 5 to 10 mm from a position where the edge 12 contacts the side plate 31. It is arranged at the position shown in the perspective view,
The remaining voids in the outer shell were filled by injecting and foaming urethane foam 8. In the heat-insulated box 37 obtained as described above, the existing door used for the conventional heat-insulated box was installed in the heat-insulated box.

[Comparative Sample] FIG.
As shown in the cross-sectional view of FIG. 7, a heat insulating box 37 of a refrigerator disposed at a position on the heat insulating wall 36 not including the corners was manufactured so as to have the same form as the above-described heat insulating box according to the present invention. As the door used for the heat-insulating box 37, the same one used for the heat-insulating box according to the present invention described above is reused, and an excessive difference in heat leakage from the heat-insulating box 37 is eliminated. It did not occur.

[Evaluation Method] In order to evaluate the heat insulating performance of the heat insulating box obtained by the above means, the amount of heat leakage was measured. The amount of heat leakage is measured by putting a heater with a known calorific value Q into the refrigerator and measuring the air temperature Tin inside the heat insulation box and the air temperature Tout outside the heat insulation box. The amount of heat leakage per temperature difference, that is, the thermal conductance K was determined.

K = Q / (Tin−Tout) (4)

[Results] Table 1 shows the heat insulating performance of each of the heat insulating boxes of the refrigerators according to the embodiment in which the vacuum heat insulating panel is provided by the mounting method of the present invention and the comparative example according to the conventional mounting method. The measurement results of the amount of heat leakage are described.

[0073]

[Table 1]

In the case of a conventional heat-insulating box in which an edge portion of a vacuum heat-insulating panel is disposed on a heat-insulating wall forming a plane of an outer box, a package formed by receiving heat from the outer box and then disposed in the heat-insulating direction at the edge portion. Since the urethane foam, which is a heat insulating material, penetrates from a thin position through the aluminum foil of the material and flows into the inside of the storage from a thin surface, the apparent heat insulating performance of the heat insulating box deteriorates.

At this time, the heat insulation box according to the present invention
A vacuum insulation panel including a right-angled edge portion is disposed at a corner where the right-angled edge portion is in a region where an adjacent heat-insulating wall intersects, and the remaining acute-angled edge is provided. The side portion was located on a flat heat insulating wall. As a result, the thickness from the urethane foam that fills the remaining voids to the inner box increases at the corners where the right-angled edge portions are arranged, so that the heat-insulating box body concentrated from the edges and the like. Since it is possible to suppress the heat from reaching the inside, the amount of heat leakage can be suppressed, and a heat insulating box having excellent heat insulating performance can be obtained.

Further, as shown in FIG. 12A, even when the right side edge portion 30 comes into contact with the fitting portion 33 of the outer box 6, the edge portion 30 does not turn back but is only bent at an angle of 90 degrees. In addition, cracks and other defects are unlikely to occur in the aluminum foil in the packaging material of the vacuum insulation panel due to the occurrence of folds. However, when the end portion 35 forming an acute angle comes into contact with the outer peripheral end portion 38 at the opening portion of the heat insulating box 37, a large deformation such as folding in almost the opposite direction as shown in FIG. Will come. In addition, since the end portion has an acute angle that is easily damaged, a defective portion may be generated in the packaging material and the degree of vacuum may be reduced in some cases. For this reason, it is preferable that the end portion 35 forming an acute angle is disposed so as to be located on the wall surface of the outer box 6, whereby the end portion 12 at the end portion comes into contact with the outer peripheral end portion 38 and is bent. Even if it is done, the packaging material is hardly damaged, so that it is possible to avoid lowering the degree of vacuum and impairing the heat insulating property, which is preferable.

As described above, the edge portion of the vacuum heat insulating panel is placed in a region where the wall surface portion, such as the side surface and the back surface and the ceiling, where the thick urethane foam as another heat insulating material is formed, intersects and joins. Since it is arranged so that it is located
It was possible to suppress a decrease in heat insulation performance due to the influence of thermal crosslinking at the edge portion of the vacuum heat insulation panel.

With respect to the embodiments of the present invention described above, the present invention is not limited to the above-described heat insulating structure for refrigerators as shown in the drawings and the embodiments. And prefabricated refrigerators, cold storage vehicles, pipes, heat insulation materials for buildings, and other heat insulation and cooling products can be applied to heat insulation parts. Can be.

[0079]

According to a first aspect of the present invention, there is provided a vacuum heat insulator comprising a structure having continuous pores therein and maintaining a vacuum state, wherein the vacuum heat insulator is opposed to the vacuum heat insulator. When the ratio L2 / d of the thickness d of the two surface portions to the length L2 of the outer peripheral portion of the vacuum heat insulator that becomes thinner toward the outside is 2.0 or more. Since it includes a certain edge, the distance from the heat receiving surface, which is the main heat transfer path, to the facing surface can be extended to suppress a decrease in heat insulation performance due to thermal crosslinking.

Further, in the vacuum heat insulator according to the second aspect of the present invention, the ratio L2 / d of the thickness d of the surface portion to the length L2 of the edge portion is 3.7 or less. Since it has a shape, the extension of the heat transfer path does not cause an excessive decrease in the heat insulation thickness, so that a decrease in the heat insulation performance can be effectively suppressed.

Further, in the vacuum heat insulator according to the third aspect of the present invention, since the end portion forms a non-linear shape composed of a combination of straight lines having an arc or an obtuse angle, the main heat transfer is achieved. The path can be efficiently extended within a short area.

Further, in the vacuum heat insulator according to the fourth invention of the present invention, the surface portion composed of the two opposing surfaces has a length L1 of the shortest side constituting the surface and a thickness d of the vacuum heat insulator.
And the ratio L1 / d is 20 or more, it is difficult to reduce the heat insulation performance by suppressing the influence of thermal crosslinking.

A heat insulating structure according to a fifth aspect of the present invention includes a surface portion composed of two opposing surfaces and an edge portion having a shape in which the outward direction becomes thinner. Ratio L2 / d between the length d and the length L2 of the end portion.
Is provided in the outer shell, and the remaining voids are filled with a porous body containing independent air bubbles. In addition, it is possible to obtain the original heat insulation performance by reducing the influence of the heat dissipation, and it is difficult to include voids such as voids, so that it is possible to obtain excellent heat insulation performance and design properties.

Further, in the heat insulating structure according to the sixth aspect of the present invention, the ratio d / dt of the thickness D of the vacuum heat insulator to the heat insulating material distance dt in the outer shell in which the vacuum heat insulator is disposed is 0. 0.5-0.5.
With the configuration of 7, the heat transfer by the thermal bridge at the end portion and the suppression of the penetration heat by the heat insulating material in the outer shell are effectively secured, and the excellent heat insulating performance can be secured.

Further, in the heat insulating structure according to the seventh aspect of the present invention, since the vacuum heat insulator has an inclined side portion located inside the heat insulating wall, the edge portion located at the end portion is provided. Since 12 is not bent by abutting on the outer peripheral end portion 38, damage to the packaging material, reduction in the degree of vacuum, and impairment of heat insulation can be avoided.

The heat insulating structure according to an eighth aspect of the present invention is characterized in that the vacuum heat insulator is formed at a right angle without a slope at the end, and the edge portion of the vacuum heat insulator is formed as a wall surface. Are disposed so as to be located in the outer shell of the corner where the crossing is made, so that even if the end portion is affected by thermal crosslinking, a thick porous body containing independent bubbles is provided. As a result, it was possible to obtain a material having a small decrease in heat insulation performance.

The heat insulating structure according to the ninth aspect of the present invention is characterized in that the vacuum heat insulator has a ratio L1 / d of the length L1 of the short side constituting the facing surface to the thickness d of 20 or more. Therefore, the effect of heat transfer to the heat-receiving surface due to the thermal crosslinking was small, and the heat-insulating performance was hardly reduced.

[Brief description of the drawings]

FIG. 1, showing an example of an embodiment of the present invention, is a cross-sectional view illustrating an edge structure of a vacuum heat insulating panel and a state of disposing a heat insulating structure.

FIG. 2, showing an example of an embodiment of the present invention, is an explanatory diagram showing an arrangement position of a heat flow sensor required for measuring a heat transfer amount in a plane direction.

FIG. 3, showing an example of an embodiment of the present invention, is a conceptual diagram of an apparatus for measuring a heat transfer amount.

FIG. 4, showing an example of an embodiment of the present invention, is a relationship diagram illustrating a relationship between the inclination of an end portion and the amount of heat leakage.

FIG. 5, showing an example of an embodiment of the present invention, is an explanatory diagram showing a relationship between the thickness of a plate-like sample and the thickness of a vacuum heat insulating panel.

FIG. 6, showing an example of an embodiment of the present invention, is an explanatory view showing an arrangement position of a heat flow sensor required for measuring a through heat quantity.

FIG. 7, showing an example of an embodiment of the present invention, is a relationship diagram showing a relationship between a ratio of a heat insulating material to a thickness of a vacuum heat insulating panel and an amount of heat leakage.

FIG. 8, showing an example of an embodiment of the present invention, is a relationship diagram showing a relationship between a ratio of a thickness to a short side length and a heat leakage amount in a vacuum heat insulating panel.

FIG. 9 shows an example of the embodiment of the present invention, and is a conceptual diagram showing another shape at an end portion of the vacuum heat insulating panel.

10 is a view showing one example of the embodiment of the present invention, and is an explanatory view showing a heat flow path provided for heat leakage in the edge shape of FIG. 10;

FIG. 11 is a conceptual diagram showing an example of an embodiment of the present invention and showing a shape of an edge portion of still another vacuum heat insulating panel.

FIG. 12, showing an example of an embodiment of the present invention, is a cross-sectional view illustrating an embodiment of a vacuum heat insulating panel provided on a wall surface of a heat insulating box.

FIG. 13 is a perspective view showing an example of an embodiment of the present invention and showing a position where a vacuum heat insulating panel is provided in a heat insulating box.

FIG. 14 shows an example of a conventional embodiment, and is a comparative diagram showing the performance of various heat insulating materials.

FIG. 15 shows an example of a conventional embodiment, and is a cross-sectional view showing an internal structure of a vacuum heat insulating panel.

FIG. 16 is a cross-sectional view showing an example of a conventional embodiment and showing a state where a vacuum heat insulating panel is disposed on a heat insulating wall of a refrigerator.

FIG. 17 illustrates an example of a conventional embodiment, and is a process diagram illustrating a method of manufacturing a vacuum heat insulating panel.

FIG. 18 illustrates an example of a conventional embodiment, and is a cross-sectional view illustrating a configuration of a packaging material.

FIG. 19 is a cross-sectional view showing an example of a conventional embodiment and showing an example of an edge portion structure in a packaging material.

FIG. 20 is a cross-sectional view showing an example of the conventional embodiment and showing an example of an end portion in another conventional vacuum heat insulating panel.

[Explanation of symbols]

1 vacuum insulation panel, 2 core materials, 5 insulation walls, 6 outer box, 7 inner box, 8 urethane foam, 12 edges, 24
Surface portion, 30 right side edge portion, 34 heat insulating wall corner portion, 35 acute angle side portion, 36 heat insulating wall surface, 37
Insulated box.

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3E070 AA08 AA25 DA01 DA09 LA07 NA04 NA06 3H036 AA08 AB18 AB25 AB28 AC01 3L102 JA01 MA07 MB22 MB27

Claims (9)

[Claims] 1. A vacuum heat insulator comprising a structure having continuous pores therein and maintained in a vacuum state, wherein a thickness d of two opposing surface portions of said vacuum heat insulator is defined by: The ratio L2 / d to the length L2 of the end portion of the outer peripheral portion of the heat insulator that becomes thinner toward the outside is 2.
A vacuum insulator comprising an edge that is greater than or equal to zero. 2. An end portion having a shape in which a ratio L2 / d of a thickness d of the vacuum heat insulator to a length L2 of the end portion is 3.7 or less. The vacuum insulator as described. 3. The vacuum heat insulator according to claim 1, wherein the non-linear shape is formed by a combination of an end portion, a straight line having an arc or an obtuse angle. 4. A ratio of L1 / d between the length L1 of the shortest side constituting the surface and the thickness d of the vacuum heat insulator is 20 or more. The vacuum heat insulator according to claim 1 or 2, wherein: 5. A vacuum heat insulator having a thickness d and a length L2 of the vacuum heat insulator, comprising a surface portion composed of two opposing surfaces and an edge portion having a shape that becomes thinner in an outward direction. A heat insulating structure in which a vacuum heat insulator including an edge having a ratio L2 / d of 2.0 or more is disposed in an outer shell, and the remaining voids are filled with a porous material containing independent air bubbles. . 6. The ratio d / dt of the thickness d of the vacuum heat insulator to the thickness dt of the heat insulator in the outer shell in which the vacuum heat insulator is disposed is 0.5.
The heat insulating structure according to claim 5, comprising a configuration of -0.7. 7. The heat insulating structure according to claim 5, wherein the vacuum heat insulating body has an inclined end portion located in the heat insulating wall surface. 8. The vacuum heat insulator is positioned in the outer shell of the corner where the wall surface intersects the end portion of the vacuum heat insulator formed in a right-angled manner without having a slope at its end. The heat insulating structure according to any one of claims 5 to 7, wherein the heat insulating structure is provided on a surface of the heat insulating structure. 9. A vacuum heat insulator having a configuration in which a ratio L1 / d of a length L1 of a short side constituting an opposing surface to a thickness d thereof is 20 or more. 9. The heat insulating structure according to any one of 5 to 8.