JPH10238691A - Vacuum heat insulation panel, manufacture thereof, and refrigerator using vacuum heat insulation panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress heat transfer quantity and radiating heat transfer quantity by forming a core member, which holds a shape of a vacuum heat insulation panel, of porous material which is made of continuously foamed hard polyurethane foam containing plate filler. SOLUTION: After plate filler made of inorganic matter such as mica, which is excellent in radiating heat shielding effect, or metallic foil of aluminum and the like, which is provided with high density and excellent in a heat reflecting property, is mixed with hard polyurethane foam, the hard polyurethane foam is foamed and molded flowingly inside a thin plate metal die so as to be provided as a molded material, and then, the molded material is used for a core member 2 in a vacuum heat insulation panel 7. The plate filler is oriented in the surface direction of the core member 2. In this way, heat transmission through a substance is controlled in the surface direction orthogonal to the heat insulating direction, so that heat transmitting quantity in the heat insulating (thickness) direction can be suppressed while heat transfer quantity based on radiation can be also reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum heat insulating panel used as a heat insulating material disposed in a gap formed of a thin metal plate and a resin molded product on a wall of a refrigerator or a refrigerator car requiring heat insulation. More specifically, even if the outer shell is inside a container or packaging material made of an air-impermeable film such as aluminum foil, etc. The present invention relates to a vacuum heat insulating panel provided with a core material having a function of maintaining a shape without causing deformation, a method for manufacturing the same, and a refrigerator using the vacuum heat insulating panel.

[0002]

2. Description of the Related Art Conventionally, the wall surface of a heat insulator used for refrigerators, cold storage vehicles and the like is covered with a thin metal plate such as an iron plate, and the inner surface is formed of a resin molded product. And then filled. The foaming agent for rigid urethane foam as a heat insulating material includes 1,1-hydrochlorofluorocarbons.
Dichloro-1-fluoroethane has been used, but in recent years, it has been proposed to use hydrofluorocarbons and hydrocarbons which do not contain chlorine which causes ozone layer destruction in the molecule.

For example, Japanese Patent Application Laid-Open No. 2-235982 discloses that 1,1,2,2,3-pentafluoropropane (H
FC-245fa) and hydrofluorocarbons such as 1,1,1,4,4,4-hexafluorobutane (HFC-356mffm) are disclosed in JP-A-3-152160.
In the publication, hydrocarbons such as cyclopentane are
A method for producing a rigid polyurethane foam applied to a blowing agent is disclosed. However, the heat insulation properties of these rigid polyurethane foams are 19 to 20 mw / mk, which is apparent from comparison with the heat insulation properties of 16 mw / mk when chlorofluorocarbons used before the specification regulation of the ozone depleting substance are used. Inferior.

[0004] For this reason, FIG.
As shown in (1), there has been proposed a technique of applying a vacuum heat insulating panel capable of obtaining heat insulating performance twice or more that of a conventional vacuum heat insulating panel formed of a rigid polyurethane foam.
For example, Japanese Patent Application Laid-Open No. 60-243471 discloses an insulated box body in which a crushed product of a rigid polyurethane foam (hereinafter, referred to as PUF) is put into a synthetic resin bag and vacuum-packed in a board shape and arranged in a wall. And Japanese Patent Application Laid-Open
Japanese Patent Application Laid-Open No. -60483 discloses a method of installing a vacuum heat insulating panel in which a gap through which PUF flows is provided on a flange side of a side plate. The core material of such a vacuum insulation panel has a strength equal to or higher than the atmospheric pressure, and it is necessary to suppress the amount of heat conduction and radiant heat transfer. Plates made of porous material are used.

[0005]

In order to satisfy the above conditions, Japanese Patent Application Laid-Open No. 60-205164 discloses a rigid polyurethane foam having open cells, and Japanese Patent Application Laid-Open No. 60-718.
No. 81, pearlite powder is disclosed in Japanese Patent Application Laid-Open No. 4-2185.
No. 40 discloses a plate-like molded product obtained by sintering a thermoplastic urethane resin powder in a mold, and JP-A-7-96580 discloses a resin fiber obtained by fibrillating long glass fibers into inorganic fine powder. The solidified board is used as the core material of the vacuum insulation panel. However, these methods only partially apply a heat insulating mechanism required as a core material of the vacuum heat insulating panel, and thus have insufficient heat conductivity as the vacuum heat insulating panel.

[0006] For this reason, in order to achieve an improvement in heat insulation performance, Japanese Patent Application Laid-Open No. 62-13979, in which a metal foil or a metal vapor-deposited film having an excellent radiation heat shielding effect is embedded, or a fine powder such as calcium silicate is mixed. There is an invention disclosed in Japanese Patent Application Laid-Open No. 63-135694 using the above PUF.

[0007] However, mixing a particulate substance such as calcium silicate requires a considerable amount, and the thermal conductivity of these fillers does not provide sufficient heat insulating properties. Further, even in the case of the core material provided with the metal foil, the heat transfer is developed only in the plane direction and does not attenuate, so that the structure does not have the effect of suppressing the heat transfer between the materials. In addition, PU described in Japanese Patent Application Laid-Open No. 60-243471.
If the pulverized product of F is used as it is, handling becomes difficult, for example, the volume is greatly reduced after being inserted into the vacuum insulation panel or the inside of the packaging bag is evacuated.

The present invention has been made to solve the above problems, and can be manufactured without causing environmental destruction, can maintain a vacuum-shaped panel shape, and suppress the amount of heat transfer and radiant heat transfer. It is an object of the present invention to obtain a vacuum insulating panel having high heat insulation, lightweight, excellent in mass production, excellent in handling at the time of manufacturing, high insulative property, and a refrigerator using the vacuum insulating panel.

[0009]

[Means for Solving the Problems]

(1) A vacuum heat insulating panel according to the present invention is a vacuum heat insulating panel whose shape is maintained by a core material, wherein the core material is a porous body made of open-celled rigid polyurethane foam containing a plate-like filler. It is composed. (2) In the vacuum heat insulating panel of the above (1), the surface of the plate-like filler is oriented parallel to the surface direction of the core material.

(3) In the vacuum insulation panel according to the above (1) or (2), at least one of an inorganic substance and a metal is used as the plate-like filler. (4) In the vacuum heat insulating panel according to the above (3), flake mica is used as the plate-like filler. (5) In the vacuum insulation panel according to (3), a plastic film is used as the plate-like filler.

(6) In the vacuum insulation panel according to the above (3), a plastic film in which a plate-like filler is coated with a thin metal film is used. (7) In the vacuum insulation panel according to the above (3), a metal foil is used as the plate-like filler. (8) In the vacuum insulation panel according to (6) or (7), aluminum is used for the metal thin film or the metal foil.

(9) The above (1), (2), (3),
In the vacuum heat insulating panels described in (4), (5), (6), (7) and (8), a release agent was applied to the surface of the plate-like filler. (10) The above (1), (2), (3), (4),
In the vacuum heat insulating panels described in (5), (6), (7), (8) and (9), the size of the plate-like filler is larger than the cell size of the rigid polyurethane foam. (11) In the vacuum heat insulating panel described in the above (1) and (2), the surface layer of the core material is deleted.

(12) In the vacuum insulation panel according to the present invention, a plate-like filler and a raw material liquid for a rigid polyurethane foam are mixed and injected from an end of a plate-like mold, and foamed from the end to flow in the flow direction. The shear is applied so that the surface of the plate-shaped filler is oriented parallel to the surface direction of the plate-shaped molded product.

(13) In the method for manufacturing a vacuum insulation panel according to the above (12), a release agent is applied to the plate-like filler, and the plate-like filler is mixed with a premix liquid as a raw material liquid of a rigid polyurethane foam and an isocyanate. Inject just before mixing the liquid, inject these mixed raw materials from the end of the plate-shaped mold in time for foaming, foam from this end, and apply shear in the flow direction by subsequent foaming, plate-shaped The surface of the filler was oriented parallel to the surface direction of the plate-shaped molded product.

(14) In the method for producing a vacuum insulation panel according to the above (12) or (13), the foaming rate of the rigid polyurethane foam is increased. (15) In the method for manufacturing a vacuum insulation panel according to the above (12) or (13), the ratio L / T of the thickness T of the molded product to the flow distance L of the foaming liquid is set to 10 or more.

(16) The refrigerator according to the present invention is provided with a vacuum insulation panel having a core made of open-celled rigid polyurethane foam containing a plate-like filler between the inner box and the outer box. (17) In the refrigerator of (16), the vacuum insulation panel was attached to the inner box or the outer box, and the remaining space was filled with a rigid polyurethane foam.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 In order to improve the heat insulation performance, a material having low heat conductivity is used as a constituent material, the contact area between the materials is reduced, and the heat transfer through the material is controlled in a plane direction perpendicular to the heat insulation direction. Suppressing heat transfer in the heat insulation (thickness) direction,
It is necessary to provide a heat insulating mechanism that mixes a substance having a high heat reflecting ability to reduce the amount of heat transfer by radiation.

In the present invention, a rigid polyurethane foam is mixed with a high-density and highly heat-reflective plate-like filler such as an inorganic material such as mica or a metal foil such as aluminum which is excellent in shielding effect of radiant heat. A molded product obtained by foam molding so as to flow in a mold is used as a core material of a vacuum heat insulating panel. Moreover, in order to eliminate closed cells in the molded article, in addition to using a conventional rigid polyurethane foam having open cells, a release agent is applied to a plate-like filler and used.

The insulation performance is improved by using the rigid polyurethane foam of the open cell mixed with the plate-like filler constituted as described above as the core material of the vacuum insulation panel. The mechanism is considered to be as follows. Can be That is, the plate-like filler having an excellent radiation heat shielding effect flows in the mold as the rigid polyurethane foam expands and expands, while maintaining the state of mixing with the foaming liquid of the rigid polyurethane foam.

At this time, the flow direction which is less susceptible to shearing force generated by the flow velocity difference based on the flow resistance received on the mold surface,
That is, the plate-like filler is oriented in the plane direction. Even though the heat transfer coefficient of the plate-like filler is larger than that of the rigid polyurethane foam, by orienting in a plane direction perpendicular to this heat insulating direction, it is not continuously contacted and oriented in the heat insulating direction, and Since it is a very thin substance, heat transfer in the thickness direction does not significantly deteriorate the heat insulating effect.
Moreover, since the plate-like filler is a flake-like small piece, it is not continuous in the lateral direction, and the amount of heat transfer is not attenuated and spread.

Therefore, as compared with the conventional case where only the rigid polyurethane foam having open cells is used as the core material, the increase in the amount of heat transferred through the substance is negligible, and the decrease in the amount of radiant heat is greater than that. It is thought that the heat insulation performance of the filled heat insulator can be improved by this. Furthermore, since it is a composite in which plate-shaped fillers are arranged in a plane direction on rigid polyurethane foam, these cores can sufficiently secure compressive strength exceeding the atmospheric pressure that they receive under vacuum, and the cores in the vacuum insulation panel can be secured. Does not deform due to the atmospheric pressure received when the interior of the packaging material is evacuated.

On the other hand, in order to prevent the deterioration of the heat insulation performance due to the remaining closed cells releasing the gas inside and reducing the degree of vacuum in the system in order to maintain the vacuum state inside the core material, 100 to 2 constituting polyurethane foam
Care must be taken to break individual bubbles having a size of 00 μm, that is, membranes existing at cell boundaries to make them communicate. As a countermeasure, the size of the plate-shaped filler is made larger than the cell size, that is, the cell size, and by applying a release agent, the rigid polyurethane foam shrinks when it is resinified. A function to be achieved by creating new voids while destroying the cell membrane that penetrates when peeling off from the plate-like filler disposed in the above.

FIG. 1 is an explanatory view schematically showing a manufacturing process of a vacuum heat insulating panel. As shown in the figure, first, a plate-like filler A prepared by crushing mica or cutting aluminum foil, etc.
, A premix liquid B prepared from a polyol liquid, a catalyst, a communicating material, a foaming agent, and the like, and an isocyanate liquid C are mixed (step S-1), and these are charged into a mold and molded. Step S-2). Next, the surface layer of the molded product is deleted (Step S-3), and the outer periphery is cut (Step S-4).

Then, this is inserted into a packaging material (step S-5), and evacuated (step S-6) and welded with end pieces (step S-7) by a vacuum panel forming machine, and taken out (step S-5). -8). The manufacturing process of the vacuum insulation panel as described above further includes (1) creation of a core material (step S-1 to step S-4), and (2) creation of a vacuum insulation panel (step S-5 to step S-). 8) will be described in detail.

(1) Preparation of Core Material (Step S-1 to Step S-4) A core material obtained by compounding a rigid polyurethane foam and a mica as a plate-like filler and foam-molding it into a board is taken as an example.
First, a method of forming the core will be described in detail. (A) Adjustment of Plate-like Filler A The plate-like filler needs to have excellent heat reflectivity, and is preferably a high-density substance such as an inorganic substance or a metal. Also, in view of the price reflected from the ease of forming the plate-like pieces, it is most preferable to use aluminum foil or mica. The same effect can be obtained by using a plastic film, which is a low-density substance, with the surface coated with a metal film such as aluminum.

Here, a case where mica is used in the form of flakes will be described. Flake mica has a rigid polyurethane foam cell size of 70 μm to 200 μm.
m, a diameter of 0.1 mm or more, preferably 5 mm to 0.1 mm, more preferably 2 mm
Crush to a size of mm to 0.5 mm. For the crushing at this time, if a high-speed water flow by a water jet is applied,
Peeling between the layers is also performed at the same time to obtain thinner flake-like mica. A 1% to 10% solution of a paraffin-based or silicone-based release agent is sprayed on these plate-like fillers, the surface is covered by a method such as injection or immersion, and then the solvent is removed by hot-air drying. And apply it.

(B) Preparation and foam molding of rigid polyurethane foam raw material liquids B and C (step S-1 to step S-1)
-2) The rigid polyurethane foam raw material liquid includes a premix liquid containing a polyol, a catalyst, a foam stabilizer, a foaming agent, a foaming agent, and the like, and an isocyanate liquid containing isocyanate as a main component. The foaming is started by mixing the respective prescribed amounts. An arbitrary amount of the plate-like filler to which the release agent has been applied is charged immediately before mixing them.

These raw materials are mixed using an impeller-type mixer, and charged into a mold in time for foaming to be started after a few seconds. The mold temperature at this time is 30 ° C.
60 ° C is preferred, and 40 ° C to 50 ° C is particularly preferred. The preferred ratio (L / T) of the thickness T of the molded product to the flow distance L of the foaming liquid of the mold used is 10 or more, and particularly preferably 20 to 40. The flow distance L is 1000
mm or less is suitable for obtaining a homogeneous molded product.

More specifically, the size of the mold used for carrying out the following examples was as follows: width (W): 300 mm, flow distance (L): 500 mm, and molded product thickness (T): 30 mm. Was. As for the mixed liquid, the raw material is charged so that the liquid only accumulates at the end portion where the mold is inclined at 45 degrees. Immediately after the charging, the mold is sealed and allowed to stand. Goods secured.

(C) Manufacture of core material (Step S-3 to Step S-4) The obtained molded product may be used as the core material as it is, but preferably, shearing applied to the surface portion in contact with the mold Not only is the force insufficient, the orientation of the plate-like filler is insufficient, but also many closed cells remain, which are removed by cutting or the like.
The thickness to be removed is preferably 2 mm or more, particularly preferably 5 mm or more. Also, the outer periphery is cut to obtain a predetermined size.

(2) Preparation of Vacuum Insulated Panel (Step S)
-5 to Step S-8) The core material is obtained by storing the core material in the packaging material of the multilayer sheet, and then thermally welding the insertion port under a vacuum atmosphere. Hereinafter, a method for forming the vacuum heat insulating panel will be described. For the core material,
A sheet cut and adjusted to obtain a predetermined surface size is used. The sample used for various evaluations, mainly for heat insulation, is inserted into a packaging material that has been heat-sealed in three directions in advance and then loaded into the apparatus shown in FIG. 2 to secure an atmosphere of a predetermined degree of vacuum. Then, the remaining one direction was obtained by heat sealing. The degree of vacuum was an arbitrary value between 1 × 10 ^{1 and} 10 ^-3 Torr.

That is, as shown in FIG. 2, after the core material 2 inserted into the packaging material 1 is mounted between the upper and lower fusing heaters 3, 3, the inside of the vacuum panel forming machine 4 is moved to a predetermined position. The degree of vacuum is adjusted by the vacuum adjustment valve 5. After that, the insertion opening is fixed using the sealing pressurizing devices 6 and 6,
After the heat sealing, the heater is turned off, and after cooling, the vacuum is released and taken out, whereby the vacuum insulation panel 7 is obtained.

The packaging material 1 used here is made of a thermoplastic resin having a sealing surface capable of being heat-sealed, a metal foil such as an aluminum foil for an intermediate layer for completely blocking the invasion of the outside air, and a scratch on the outermost layer. This is a multi-layer sheet using a resin such as nylon or polyester that is resistant to water. The core material 2 has a thickness of 20
mm and a surface of 180 × 180 mm were used. Also,
The core material 2 and the packaging material 1 were used after drying at a temperature of 100 ° C. or higher.

FIG. 3 is an explanatory view showing an outline of a process of assembling a product (in this case, a refrigerator) using a vacuum heat insulating panel. FIGS. 4 and 5 are perspective views showing the use state of the assembled product and the main parts thereof. It is a longitudinal cross-sectional view of a. As shown in the figure, the vacuum insulation panel 7 was attached to the outer box 8 (Step S-
1) After that, the inner box 9 is inserted into the fitting portion of the outer box 8 (Step S-2) to be combined, and assembly of the box including other members is completed (Step S-3). Next, the outer box 8 and the inner box 9
A heat-insulating layer 10 is formed by injecting a raw mixture of a rigid polyurethane foam into the space formed between them and foam-molding the mixture (step S-4). Thereafter, the internal components and the refrigerant circuit components are used to arrange the internal components and assemble the refrigerant circuit product (step S-5). If the product inspection is completed (step S-6), the product is completed (step S-6). -7).

The core material obtained as described above and incorporated in the product was evaluated with respect to the heat insulating performance, its temporal change, and the temporal change of the shape by using the obtained vacuum heat insulating panel (hereinafter, referred to as a “temporal change”). Examples A to G). The heat insulation performance was evaluated based on the thermal conductivity, and “Auto Lambda” manufactured by Eiko Seiki Co., Ltd. was used for the measurement. Further, the change with time of the heat insulation performance was evaluated by determining the thermal conductivity after leaving the vacuum heat insulation panel in an atmosphere at 50 ° C. for an arbitrary time, and evaluating the change with the change immediately after the sample was prepared. The change over time of the shape
In particular, visual observations were made on the deformation of the side portion where shrinkage was easily determined.

Example A The confirmation of the effect of improving the heat insulating performance will be described below. First, the composition of the core material used as a sample in Examples 1 to 3 of the present invention is shown in Table 1.

[0037]

[Table 1]

The rigid polyurethane foam used had a density of 45 kg / m ³ when foamed alone, and the flaky mica used had an average diameter of 1.0 mm. After taking the two liquids of the rigid polyurethane foam and the flake-like mica into a beaker, immediately stir with a high-speed stirrer to obtain 500 L × 3
The temperature was adjusted to 45 ° C. at 00 W × 30 T (mm), and the mold was charged into the short side. At this time, an excess filling amount of 10% with respect to the minimum necessary amount for completely filling the mold was charged, and the mold was hermetically sealed and allowed to stand for 7 minutes to obtain a board-shaped molded product. As the core material, a board obtained by removing the surface layer of 2.5 mm from the board-shaped molded product and further cutting the board into a size of 180 × 180 (mm) was used.

As comparative examples of the present invention, open-cell rigid polyurethane foam (comparative example 1) represented by JP-A-60-243471 as a conventional vacuum insulation panel, and JP-A-62-13979. Each of aluminum foils having an excellent radiation heat shielding effect disclosed in the gazette and disposed between thin plates of open-celled rigid polyurethane foam (Comparative Example 2) was used as the core material. The open-celled rigid polyurethane foam of Comparative Example 1 had a density of 45 kg / m ³ ,
A cell having a cell size of 300 μm was used. As Comparative Example 2, a core obtained by cutting the above rigid polyurethane foam at the center and sandwiching an aluminum foil having a thickness of 10 μm was used as a similar core material.

The vacuum insulation panel used as a sample has a thickness of 20 mm and a surface size of 180 × 180 mm for each of the above core materials.
It was used after being dried at 150 ° C. for about 1 hour. The vacuum insulation panel used as the sample is 110 ° C
And then heat-sealed in an arbitrary vacuum atmosphere of 10 ⁰ to 10 ^-3 Torr.

Comparative Example 1 using a rigid polyurethane foam core having open cells in addition to the samples of Examples 1 to 3, a core material in which an aluminum foil was sandwiched between rigid polyurethane foams having open cells. In Comparative Example 2 used, similar samples of vacuum insulation panels were prepared in which the degree of vacuum at the time of heat sealing was adjusted to an arbitrary degree of vacuum of 10 ¹ to 10 ⁻³ Torr, and the vacuum dependence of the heat insulating performance of these samples was prepared. FIG. 6 shows the results of the evaluation. Table 2 shows that the degree of vacuum was 10 ⁻² Torr from the results of FIG.
Heat insulation performance at r equivalent and up to 30 in 50 ° C atmosphere
Changes over time after standing for a day, and the results of evaluation of deformation were also shown.

[0042]

[Table 2]

From the above results, the heat insulating performance of the vacuum heat insulating panel of the present invention using the core material in which mica is oriented in the plane direction by foaming and flowing of the rigid polyurethane foam is as follows:
Compared to conventional open-cell rigid polyurethane foam,
The thermal conductivity was reduced by about 10 points or more, that is, the heat insulation was improved. Further, as for the change with time of the product of the present invention, the core material is a rigid polyurethane foam having open cells, which is a conventional material not containing flaky mica, as shown in Comparative Examples 1 and 2 in both thermal conductivity and deformation. It was confirmed that the results showed more stable results than the vacuum heat insulating panel used as the sample.

Example B Next, the size of the flake mica which is the material composition of the present invention will be described. Using a core material prepared by the same molding method as in Example A and an evaluation method using a material composition having different sizes of flake-like mica to be filled in the open-celled rigid polyurethane foam, a vacuum atmosphere of 10 ^-2 Torr was used. The heat insulation performance (an initial value and a value after a change over time after being left at 50 ° C. for 10 days) as a sample corresponding to the vacuum heat insulation panel enclosed in the packaging material was evaluated.

Table 3 shows the average diameter of the mica flakes used.
As shown in the figure, the average diameter was changed from 0.1 mm which is the same as the cell of the open-celled rigid polyurethane foam to 7.0 mm which is 50 times or more thereof. The heat insulation performance of the core material obtained by mixing and orienting the rigid polyurethane foams containing the flaky mica having different average diameters is 10%.
Table 3 shows the results of the evaluation after a change over time of days.

[0046]

[Table 3]

From the above results, there is almost no difference in the thermal conductivity between the examples in which the average diameter of the flaky mica is 0.2 mm to 4.0 mm, and after the change with time in the atmosphere at 50 ° C. for 10 days. There is no significant change in thermal conductivity, and there is no problem in practical use. However, when the flaky mica having a diameter of 0.05 mm of Comparative Example 3 was used, the initial value of the thermal conductivity became large, and conversely, the flaky mica having a diameter of 7 mm or more shown in Comparative Example 4 was used. When used, a large change was observed in the thermal conductivity after a lapse of time after being allowed to stand for 10 days in an atmosphere at 50 ° C., suggesting that any of these cases may hinder practical use.

Embodiment C Next, a case where aluminum foil is used as a plate-like filler will be described. Using a core material produced by the same molding method as in Example A and an evaluation method so as to obtain a composite structure of a rigid polyurethane foam having open cells and an aluminum foil having an average diameter of 1.0 mm, 10 ⁻² Torr. The heat insulation performance (initial value and the value after a lapse of 10 days of standing at 50 ° C.) of the sample corresponding to the vacuum heat insulating panel sealed in the packaging material in the vacuum atmosphere was evaluated.

Table 4 shows a vacuum insulation panel using the core material having the above-described composition as Example 6, and in order to confirm the effect, Example 2 using flake mica as the plate-like filler, and Comparative Example 1 using a rigid polyurethane foam having open cells as a core material and Comparative Example 2 using a core material sandwiching aluminum foil between rigid polyurethane foams having open cells also had an initial value of thermal conductivity and 50 ° C. The values after standing for 10 days in the atmosphere of are described.

[0050]

[Table 4]

As a result, it was confirmed that the heat insulation performance was further improved as compared with the case where flake mica was used, and that the heat insulation performance was substantially impaired as in the case of the open-celled rigid polyurethane foam shown in the comparative example. It was confirmed that the composition was effective without any deterioration with time.

Example D Next, the effect of suppressing the deterioration of the heat insulating performance exerted by the release agent of the rigid polyurethane foam and the plate-like filler compounded with the rigid polyurethane foam will be described. A core material prepared by the same molding method as in Example A and an evaluation method so as to form a composite structure with a flaky mica having an average diameter of 1.0 mm obtained by applying a release agent to the surface of a rigid polyurethane foam having open cells and an evaluation method Was used to evaluate the heat insulation performance (initial value and value after a change over time after being left at 50 ° C. for 10 days) as a sample corresponding to a vacuum heat insulating panel sealed in a packaging material in a vacuum atmosphere of 10 ⁻² Torr. did.

Table 5 shows a vacuum heat insulating panel using the core material having the above-described composition as Example 6, and Example 2 using another mold release agent for the purpose of confirming the effect. . Furthermore, in order to confirm the effectiveness of these examples, an example using flaky mica to which no release agent was applied was compared with Comparative Example 5.
For Comparative Example 1 in which only open-celled rigid polyurethane foam without a filler was used for the core material, the initial value of the thermal conductivity and the value after standing for 10 days in an atmosphere at 50 ° C. are also shown.

[0054]

[Table 5]

As a result, even if the release agent was not applied to the surface of the plate-like filler, the difference between Comparative Example 5 and Comparative Example 1 in the initial value of the heat insulating performance was due to the difference between Comparative Example 5 and Comparative Example 1. It has been confirmed that a far superior effect can be obtained as compared with the case where is used as the core material. However, the numerical value after the change with time showed deterioration that was expected to hinder practical use.
This is because, when a rigid polyurethane foam having open cells is used, since complete openness was insufficient in Comparative Example 5, a foaming gas such as carbon dioxide was released out of the cells into the remaining closed cells, This is considered to be a deterioration phenomenon of heat insulation performance caused by a decrease in the degree of vacuum accompanying this.

On the other hand, the release agent according to the present invention was applied to the surface of flake mica, and the resulting peeling off of the rigid polyurethane foam eliminates the residual closed cells. From the difference between Example 2 and Comparative Example 5, it was confirmed that deterioration with time was suppressed.

Example E Next, the effect of improving the heat insulating performance by orienting the plate-like filler charged in the rigid polyurethane foam will be described. The orientation of the plate-like filler is enhanced by increasing the foaming rate of the rigid polyurethane foam and by increasing the ratio of the flow distance to the thickness of the mold (thickness of the molded product) (hereinafter referred to as L / T). Become.

Using a core material prepared by changing the reaction rate of the open-celled rigid polyurethane foam used and the L / T, this was sealed in a packaging material under a vacuum atmosphere of 10 ^-2 Torr to form a vacuum insulation panel. The heat insulation performance was evaluated as a sample. The plate-like filler used here was flaky mica having an average diameter of 1.0 mm, and a molding method similar to that of Example A was used in order to obtain a composite structure with rigid polyurethane foam having open cells. Insulation performance equivalent to a vacuum insulation panel enclosed in a packaging material in a vacuum atmosphere of 10 ^-2 Torr using the core material prepared in the above and the evaluation method (initial value and after elapse of time after being left at 50 ° C. for 10 days) Was evaluated.

Table 6 shows the results of an examination on the influence of the flow rate when molding the core material of the vacuum heat insulating panel used for evaluating the heat insulating performance. Since the foaming flow proceeds at a substantially constant speed from the time at which foaming of the rigid polyurethane foam begins to foam (hereinafter, referred to as CT) to the time at which the rigid polyurethane foam starts to resinify (hereinafter, referred to as GT), GT which is an index of the flow speed
Core materials prepared by changing the reaction rate shown as -CT (second) and changing the amount of the catalyst used are shown together with the compositions as Example 2, Example 7, and Example 8.

[0060]

[Table 6]

Similarly, Table 6 shows the dies (3
(W × 500L × 30T), the length (flow distance) L was changed, and core materials having different L / Ts were formed. The evaluation results of the vacuum heat insulating panels manufactured using the core materials were shown in Examples 2 and 7, This is shown as Example 9 and Example 10. Further, for the purpose of confirming their effects, Comparative Example 6 using a core material obtained from a rigid polyurethane foam having a reduced reaction rate,
An example using a core material obtained from a mold having a small L / T is shown as Comparative Example 7, in which the initial value of the thermal conductivity and the value after standing for 10 days in an atmosphere of 50 ° C. are also shown.

As described above, it was confirmed that when the reaction rate was changed from Example 2 to Example 7, and then to Example 8, the heat insulating performance clearly had a tendency to improve. vice versa,
As shown in Comparative Example 6, it was also confirmed that when the reaction rate was low, the heat insulation performance was sharply reduced. The cause of these reductions is due to the orientation of the flake-like mica, which is a plate-like filler, caused by trying to minimize the shearing force generated from the velocity ratio with the wall due to flow in the plane direction. Conceivable.

Also, with respect to the L / T, it was confirmed that the heat insulation performance tended to be improved when the values of the L / T were increased from Example 10 to Example 2 and further to Example 9. On the contrary, the L / T was extremely low. In Comparative Example 7, which is smaller than the above, the heat insulating performance tends to deteriorate, and it is considered that the orientation of the filler due to the shearing force of the flow greatly contributes as a factor.

With respect to the change with time of the heat insulation performance, in each of the examples obtained under the proper conditions, the result was obtained that the change was limited to 1 to 3 points. If it did, it would cause 7-9 points worse. This is also intended to obtain cracks that tend to cause continuity due to peeling off from the plate-like filler in the thickness direction. It is considered that a situation in which the gas easily leaks is caused, and a reduction in the degree of vacuum caused by the leakage of the gas results in deterioration of the heat insulation performance.

Example F Next, the effect of improving the stability of heat insulation performance by removing the surface layer of a foam molded article will be described. On the outermost surface of the rigid polyurethane foam, there is a thin skin layer of a resin, and further below it is a core layer having a uniform and stable quality called a core layer after having a high-density skin layer. Of these, the flow resistance with the mold is large up to the skin layer, it is a high-density layer generated as a result of cracking at the interface with the core layer without flowing in the mold and almost staying on the mold surface is there. Therefore, in the surface layer up to the skin layer, a shear force does not act between bubbles accompanying the flow or between the foam and the plate-like filler, and it is considered that many closed cells remain.

A molded article of an open-celled rigid polyurethane foam containing a plate-like filler was manufactured using a core material prepared by the same molding method as in Example A and an evaluation method, and 10 ⁻² Torr.
Was evaluated for the heat insulation performance (initial value and value after a change over time after being left at 50 ° C. for 10 days) corresponding to the vacuum heat insulating panel sealed in the packaging material in the vacuum atmosphere. Here, a core material having an arbitrary thickness removed from the surface layer was prepared and used, and flake-like mica having an average diameter of 1.0 mm was used as the plate-like filler, and the rigidity of the bubbles communicated therewith. A composite structure with a polyurethane foam was obtained.

Table 7 shows the composition of the core material used for the vacuum insulation panel for evaluating the heat insulation performance and the amount of the surface layer of the plate-shaped molded product to be removed in order to obtain the core material. 11 and Example 12. After changing the length L and the thickness T of the mold (300W × 500L × 30T) used for molding to make L / T constant (16.6), the thickness T is set to 25 mm, 30 mm, and 40 mm. Produce a shaped product,
From now on each side 2.5mm, 5.0mm, 10.0mm
Was removed to form a core material having a thickness of 20 mm. Vacuum insulation panels were manufactured using these core materials having different surface removal amounts, and the evaluation results of the thermal conductivity thereof were evaluated in Examples 2 and 11,
This is shown in Example 12.

[0068]

[Table 7]

In order to confirm the stability of thermal conductivity by removing the surface layer, an example in which the surface layer is not removed is shown in Comparative Example 8 and an example in which the amount of the removed surface layer is reduced is shown in Comparative Example 9. For the vacuum insulation panel using the core material obtained by the same method as above with the L / T of the molded article being constant, the initial value of the thermal conductivity and the value after being left for 10 days in an atmosphere of 50 ° C. are also described. did.

As a result, there was almost no difference in the heat insulation performance between Examples 2, 11, and 12, and a stable result with little change with time was obtained. On the other hand, when the removal amount of the surface layer shown in the comparative example is small, the initial value of the heat insulation performance is not different from that of the embodiment, but the change with time depends on the removal amount of the surface layer. It was confirmed that deterioration occurred. The change with time can be suppressed in accordance with the amount of the surface layer to be deleted, and the amount of deterioration when the surface layer is not deleted tends to be largest. It can be said that it is impossible to endure practical use with the deletion amount in the comparative example.

Example G Next, the operation performance of a refrigerator using the vacuum insulation panel according to the present invention was measured, and its effect was confirmed. First, using a vacuum insulation panel produced by the same method as in Example 1 shown in Example A using a packaging material having an aluminum foil in the intermediate layer, the outer box 8 obtained by bending a thin steel plate was used to form an ABS resin. As shown in FIG. 5, a vacuum heat insulating panel 7 was attached to the outer box 8 side in a space formed by fitting the inner box 9 obtained by vacuum molding. In this state, as shown in FIG. 6, the rigid polyurethane foam 10 was injected into the remaining space, foamed, and filled to be completely fixed.

Example 13 A 400 L class refrigerator assembled using the heat insulating box produced by the above method was used as Example 13. On the other hand, a refrigerator using a heat-insulating box similarly manufactured using a vacuum heat-insulating panel using a rigid polyurethane foam having open cells as the core and made by the same method as in Comparative Example 1 shown in Example A was used as a comparative example. 10. Comparative Example 11: Insulated box in which all the gaps between the inner box and the outer box were filled with rigid polyurethane foam
The power consumption of all these refrigerators was determined in accordance with the power consumption B method measurement method in JIS 9607, and is also shown in Table 8.

[0073]

[Table 8]

From the above results, the power consumption of the refrigerator using the vacuum heat insulating panel of the present invention was smaller than that of the conventional refrigerator of Comparative Example 11 using only the rigid polyurethane foam as the heat insulating material. It was found that the heat insulation performance was significantly superior. Moreover, compared to the refrigerator using the same vacuum insulation panel as a part of the heat insulating material, the refrigerator of Comparative Example 10 using the conventional vacuum heat insulation panel in which the rigid polyurethane foam having open cells is the core material, It was also confirmed that a refrigerator with low power consumption can be obtained.

The refrigerator according to the embodiment of the present invention has been described above. However, the present invention is not limited to this. For example, a small refrigerator mounted on a car, a simple prefabricated refrigerator, a refrigerator car, a pipe, a building or the like may be used. It is also possible to apply the product for heat insulation and cold insulation as a heat insulation part, such as a heat insulation material, and various modifications can be made without departing from the gist of the invention.

[0076]

As is clear from the above description, according to the present invention, the following effects can be obtained. In addition,
In the description, the same numbers as those in the claims are used to describe the effects of each claim.

(1) The vacuum insulation panel according to the present invention comprises:
A vacuum insulation panel whose shape is maintained by a core material, wherein the core material is formed of a porous body made of open-celled rigid polyurethane foam containing a plate-like filler, so that the panel shape in a vacuum state is maintained. The amount of heat transfer and radiant transfer can be suppressed, and the heat insulating property is also large.

(2) Since the surface of the plate-like filler in the above (1) is oriented parallel to the surface direction of the core material, the surface of the plate-like filler is oriented in a direction orthogonal to the direction of heat penetration. Excellent heat insulation performance due to the improvement of the radiation heat shielding effect and its temporal stability can be ensured. (3) Since at least one of an inorganic substance and a metal is used for the plate-like filler of the above (1) or (2), radiant heat is easily reflected, and the heat insulating effect is improved by its blocking effect. (4) Since flaky mica is used for the plate-like filler of (3), radiant heat is easily reflected, and the heat insulating effect is improved by its shielding effect.

(5) Since a plastic film is used for the plate-like filler of the above (3), radiant heat is easily reflected,
The heat insulating property is improved by the shielding effect. (6) Since the plastics film in which the plate-like filler of the above (3) is coated with a metal thin film is used, radiant heat is easily reflected, and the heat insulating property is improved by its shielding effect.

(7) Since metal foil is used for the plate-like filler of (3), radiant heat is easily reflected, and the heat insulating property is improved by its shielding effect. (8) The above (6) or (7) Since aluminum is used for the metal thin film or metal foil, it is easy to reflect radiant heat,
The heat insulating property is improved by the shielding effect.

(9) The above (1), (2), (3),
Since the release agent was applied to the surface of the plate-like filler of (4), (5), (6), (7) or (8), the cells were connected when the urethane resin and the plate-like filler were separated. Ventilation is more reliably achieved and more reliably penetrated. In addition, the peeling has the effect of forming new voids and preventing the propagation of heat in a vacuum, so that the heat insulation is dramatically improved. (10) The above (1), (2), (3), (4),
(5) Since the size of the plate-like filler of (6), (7), (8) or (9) is larger than the cell size of the rigid polyurethane foam, efficient communication of cells is promoted. Can be. (11) Since the surface layer of the core material of (1) or (2) is deleted, the effect of shielding radiant heat is improved, and excellent heat insulating performance and temporal stability can be secured.

(12) In the method for manufacturing a vacuum heat insulating panel according to the present invention, a plate-like filler and a raw material liquid for a rigid polyurethane foam are mixed, injected from the end of a plate-like molding die, and foamed from this end. The plate-shaped filler is oriented parallel to the surface direction of the plate-shaped molded product, so that the plate-shaped filler can be oriented at right angles to the heat transfer direction. The insulation can further improve the heat insulation.

(13) A release agent is applied to the plate-like filler of the above (12), and the plate-like filler is introduced just before mixing the premix solution, which is a raw material solution of the rigid polyurethane foam, with the isocyanate solution. Inject these mixed raw materials from the end of the plate-shaped mold in time for foaming, foam from this end, and apply shear in the flow direction by subsequent foaming,
Since the surface of the plate-shaped filler is oriented parallel to the surface direction of the plate-shaped molded product, the plate-shaped filler can be oriented at right angles to the heat transfer direction. It becomes possible. In addition, it is easy to handle at the time of manufacturing and is excellent in mass productivity.

(14) Since the foaming rate of the rigid polyurethane foam of the above (12) or (13) has been increased,
Heat insulation performance can be greatly improved. (15) Since the ratio L / T of the molded product thickness T to the flow distance L of the foaming liquid in the above item (12) or (13) is set to 10 or more, the heat insulation performance can be greatly improved.

(16) In the refrigerator according to the present invention, a vacuum insulation panel having a core made of open-celled rigid polyurethane foam containing a plate-like filler is disposed between the inner box and the outer box. And power consumption can be reduced.

(17) The vacuum insulation panel of (16) is attached to the inner box or outer box, and the remaining space is filled with rigid polyurethane foam. And there is no need to change the conventional structural specifications.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a manufacturing process of a vacuum heat insulating panel.

FIG. 2 is a side view showing a vacuum insulation panel manufacturing apparatus.

FIG. 3 is an explanatory view showing a product assembling process using a vacuum heat insulating panel.

FIG. 4 is a perspective view of a product incorporating a vacuum insulation panel.

FIG. 5 is a longitudinal sectional view of a main part of FIG. 4;

FIG. 6 is a diagram showing the degree of vacuum dependence of heat insulation performance.

FIG. 7 is an explanatory diagram comparing the heat insulating performance of each heat insulating material.

[Explanation of symbols]

2 core material, 7 vacuum insulation panel, 8 outer box, 9 inner box,
10 Rigid polyurethane foam.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29K 105: 16 105: 20

Claims (17)

[Claims] 1. A vacuum heat insulating panel whose shape is maintained by a core material, wherein the core material is constituted by a porous body made of open-celled rigid polyurethane foam containing a plate-like filler. Insulation panel. 2. The vacuum heat insulating panel according to claim 1, wherein the surface of the plate-like filler is oriented parallel to the surface direction of the core material. 3. The vacuum insulation panel according to claim 1, wherein at least one of an inorganic substance and a metal is used as the plate-like filler. 4. The vacuum insulation panel according to claim 3, wherein flake mica is used as the plate-like filler. 5. The vacuum insulation panel according to claim 3, wherein a plastic film is used as the plate-like filler. 6. The vacuum insulation panel according to claim 3, wherein a plastic film in which a plate-like filler is coated with a metal thin film is used. 7. The vacuum insulation panel according to claim 3, wherein a metal foil is used as the plate-like filler. 8. The vacuum insulation panel according to claim 6, wherein aluminum is used for the metal thin film or the metal foil. 9. The vacuum heat insulating panel according to claim 1, wherein a release agent is applied to a surface of the plate-like filler. 10. The vacuum according to claim 1, wherein the size of the plate-like filler is larger than the cell size of the rigid polyurethane foam. Insulation panel. 11. The vacuum insulation panel according to claim 1, wherein a surface layer of the core material is omitted. 12. The plate-like filler is mixed with a raw material liquid of the rigid polyurethane foam, injected from an end of the plate-like molding die, foamed from the end, and subjected to shear in the flow direction. Characterized in that the surface is oriented parallel to the surface direction of the plate-like molded product. 13. A release agent is applied to the plate-like filler, and the plate-like filler is charged immediately before mixing a premix solution and a isocyanate solution, which are raw material liquids for a rigid polyurethane foam, and these mixed raw materials are mixed. Inject from the end of the plate-shaped molding die in time for foaming, foam from the end and apply shear in the flow direction by subsequent foaming, and make the surface of the plate-shaped filler and the surface direction of the plate-shaped molded product The method for manufacturing a vacuum insulation panel according to claim 12, wherein the panel is oriented in parallel. 14. The method for producing a vacuum insulation panel according to claim 12, wherein the foaming rate of the rigid polyurethane foam is increased. 15. The method according to claim 12, wherein the ratio L / T of the thickness T of the molded product to the flow distance L of the foaming liquid is set to 10 or more. 16. A refrigerator characterized in that a vacuum insulation panel having a core of open-celled rigid polyurethane foam containing a plate-like filler is disposed between an inner box and an outer box. 17. The refrigerator according to claim 16, wherein the vacuum insulation panel is attached to the inner box or the outer box, and the remaining space is filled with a rigid polyurethane foam.