JPH10238938A - Vacuum heat insulation panel, its manufacture and refrigerator using the panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vacuum heat insulation panel having excellent effect of suppressing heat transfer and radiant heat by holding a core material of the panel in a shape of a packaging material, and constituting it by a complex obtained by laminating a radiant heat shielding member having excellent shielding effect of radiant heat on a surface of a glass wool mat. SOLUTION: The vacuum heat insulation panel 3 used as a heat insulator for a refrigerator comprises a packaging material 14 having a function of maintaining vacuum thereby shutting off invasion of the atmospheric air, and a core material 15 contained in the material 14 and formed of a complex obtained by laminating a radiant heat shielding member having an excellent shielding effect of radiant heat on a surface of glass wool mat. To manufacture the material 15, there are provided the steps of forming the complex by disposing a tabular piece on the mat, drying to remove moisture of the complex, impregnating the material with resin solution, and compression cure molding it. In the molding step, the complex is cured while giving a predetermined applied pressure and molded.

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 in a gap formed of a thin metal plate and a resin molded product on a wall of a refrigerator or a refrigerator car which requires heat insulation. Is inside a packaging material that has the function of forming the outer shell of a vacuum insulation panel to block the intrusion of outside air and maintain the vacuum inside, and has the function of maintaining its shape mainly from pressurization by atmospheric pressure. The present invention relates to a core material provided, and relates to a material configuration thereof and a manufacturing method for obtaining the same.

[0002]

2. Description of the Related Art In recent years, in order to protect the global environment, chlorofluorocarbons for suppressing the destruction rate of the ozone layer and hydrochlorofluorocarbons which can be suppressed to 1/10 or less thereof have been targeted. As a technology in the future, there is a social demand for a heat insulation system capable of further improving the heat insulation performance without using a foaming agent and easily recovering and reusing the used material.

Conventionally, the wall surface of a heat insulator such as a refrigerator or an insulated car is made of a thin metal plate such as an iron plate, the inner surface is formed of a resin molded product, and the gap is filled with a rigid polyurethane foam having excellent heat insulating properties. What has been foamed and filled has been used.

[0004] Rigid urethane foam (PU)
As the foaming agent of F), 1,1-dichloro-1-fluoroethane, which is a hydrochlorofluorocarbon that provides excellent heat insulating properties, has been used. It has been proposed to use hydrofluorocarbons and hydrocarbons that are not included in the above. For example, in Japanese Patent Application Laid-Open No. 2-235982, 1,1,2,2,3-pentafluoropropane (hereinafter referred to as HFC-24
5fa. ) And hydrofluorocarbons such as 1,1,1,4,4,4-hexafluorobutane (hereinafter referred to as HFC-356mffm), and a combustible substance such as cyclopentane in JP-A-3-152160. Each describes a method for producing a rigid polyurethane foam applied to a blowing agent. However, the most excellent heat insulation properties of these rigid urethane foams applied to refrigerators and the like are 17 to 20 mw.
/ mK.

[0005] not to use substances causing ozone depletion,
In refrigerators, etc., which require effective use of resources such as recycling and reduction of power consumption, there is a limit to improving the heat insulation performance of rigid urethane foam, which is a heat insulating material. As shown in the performance comparison diagram, a technique for applying a vacuum heat insulating panel capable of obtaining heat insulation performance twice or more that of a rigid urethane foam has been newly proposed. For example, Japanese Patent Application Laid-Open No. 60-243471 discloses P
There is an insulated box in which a UF crushed product is put into a synthetic resin bag and vacuum-packed in a board shape is disposed in a wall.
Japanese Patent Publication No. 0-60483 proposes a method of installing a vacuum heat insulating panel in which a gap through which a PUF flows is provided on a flange side of a side plate.

Many of the vacuum insulation panels including the above-mentioned proposals have a plate shape with a thickness of 10 to 20 mm. After the steps shown in FIG. It is made in a state of being incorporated in. For this reason, the core material of the vacuum insulation panel needs to have a predetermined strength in order to satisfy the function of maintaining the panel shape in a vacuum state.

On the other hand, in order to improve the heat insulating performance of the vacuum heat insulating panel, it is necessary to use a material that does not easily transmit heat to the constituent materials.
It is important to reduce the contact area between the materials and to control the heat transfer in a plane direction perpendicular to the direction of heat insulation. Accordingly, it is effective to suppress the amount of heat that transfers a substance in the direction of heat insulation (thickness), to interpose a substance that suppresses radiant heat transfer, and to reduce the size of a void in suppressing radiant heat transfer. .

There have been many proposals for satisfying the above-mentioned conditions. For example, Japanese Patent Application Laid-Open No. Sho 60-205164 discloses the use of rigid urethane foam having open cells.
In Japanese Patent Application Laid-Open No. 1-218, pearlite powder is disclosed in
No. 0 discloses a plate-like molded product obtained by sintering a thermoplastic urethane resin powder in a mold. In Japanese Patent Application Laid-Open No. Hei 7-96580, a glass long fiber and an inorganic fine powder are solidified and held by a fibrillated resin fiber. Each board is applied as a core material of a vacuum insulation panel.

Regarding the application of these materials, Japanese Patent Application Laid-Open Nos. 60-208696 and 58-106292 disclose fibers at right angles to the direction of heat insulation to suppress the amount of heat transfer in order to achieve an improvement in heat insulation performance. JP-A-62-13979 in which a metal foil or a metal vapor-deposited film having an excellent radiation heat shielding effect is embedded, and JP-A-63-135694 using a PUF mixed with a fine powder such as calcium silicate. is there.

[0010]

SUMMARY OF THE INVENTION In order to improve the heat insulation performance,
The amount of heat that transfers a substance in the direction of heat insulation (thickness) by using a substance with low thermal conductivity as a constituent material, reducing the contact area between the materials, and controlling heat transfer in a plane direction perpendicular to the direction of heat insulation. It is necessary to provide a heat insulation mechanism that suppresses heat transfer and radiant heat by suppressing a radiant heat transfer by mixing a substance having a high heat reflection ability. However, the conventional method has a core material structure in which only a part of a heat insulating mechanism required as a core material of the vacuum heat insulating panel is applied, and thus the heat insulating performance of the vacuum heat insulating panel is insufficient.

That is, if a granular material such as calcium silicate or perlite or a fibrous material represented by glass fiber is directly formed into a plate shape and used as a core material of a vacuum insulation panel, contact between the materials is reduced. Although the heat transfer can be suppressed by this, the heat transfer of the material in the adiabatic direction cannot be suppressed due to the non-orientation of the material. A core material structure that fully utilizes the above-described heat insulating mechanism, such as relying only on reflection, has not been obtained.

On the other hand, even with a core material provided with a metal foil for the purpose of suppressing radiant heat transfer, the heat transfer is developed only in the surface direction and does not attenuate. It is not the structure that gained.

In addition, if a particle (powder) or fibrous substance is to be used as it is, a device for improving the compressive strength in order to eliminate deformation of the core material and a treatment for increasing the bulk density are sufficiently performed. There is a need to do. In other words, if the state is left as it is without performing these treatments, insertion into the vacuum insulation panel and the desired shape cannot be easily obtained, and the volume reduction after the inside of the packaging bag is vacuumed is large. To
It is difficult to handle the material as easily as a solidified material. In addition, the packaging material may be bent due to the deformation caused by the decrease in the volume, and a vacuum may not be maintained due to generation of defects such as cracks.

According to the present invention, the thermal conductivity of the constituent materials is low, the contact area between the materials is small, the amount of heat transmitted to the material in the heat insulating (thickness) direction is suppressed, and the heat transfer and radiant heat are further suppressed. An object of the present invention is to provide a vacuum insulation panel provided with a mechanism. It is another object of the present invention to provide a method for manufacturing a core material used for the above-described vacuum insulation panel. Still another object of the present invention is to provide a refrigerator using the above vacuum heat insulating panel as a heat insulating material.

[0015]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a vacuum insulation panel with a core material which retains the shape of a packaging material and has an excellent radiant heat shielding effect on the surface of a glass wool mat. It was composed of a complex body in which radiant heat shielding members were laminated. Further, the glass wool mat was formed by depositing glass wool in a plane direction perpendicular to the heat insulating direction. Further, the radiation heat shielding member was constituted by a plate-like piece. Further, the plate-like piece was composed of mica flake. Further, the plate-like piece was made of metal foil. Further, the plate-like piece was constituted by a plastic film coated with a thin metal film. Further, an adhesion suppressant for suppressing the adhesion of the plate-like piece was used.

Further, a core body of the vacuum insulation panel is provided with a plate-shaped piece on a glass wool mat to form a complex body, and a step of removing moisture of the complex body obtained in the complex body manufacturing step. Drying step, an impregnation step of immersing the complex dried in the drying step in a resin solution, and a compression step of curing and molding the complex impregnated with the resin in the impregnation step while applying a constant pressure. It is manufactured by a curing molding process. Further, in the complex body preparation step, a slurry liquid in which the plate-like pieces were uniformly dispersed was prepared using a glass wool mat. Further, in the complex body preparation step, a slurry liquid in which plate-like pieces were uniformly dispersed was sprayed on a glass wool mat.

[0017] Further, it is easy to bond the plate-shaped pieces to the slurry liquid in addition to the plate-shaped pieces to prevent the plate-shaped pieces from adhering to each other, and to easily bond a part of the binder to the surface of the glass wool mat. A flocculant. Acrylamide was used as a coagulant. . Microfibrillated cellulose fibers were used as the binder. Further, a thermosetting resin or a thermoplastic resin in a semi-cured state was used as the resin in the impregnation step. Further, in the compression hardening molding step, 4 to 12 layers of the complex body impregnated with the resin in the impregnation step were laminated and molded.
Further, the pressing force in the compression hardening molding step is set to 0.7 to 1.
It was 5 kg / cm2.

Further, the vacuum heat insulating panel of the present invention is disposed in a gap formed by fitting an outer case and an inner case of a refrigerator, and used as a heat insulating material. Further, a hard polyurethane foam was filled in the other space where the vacuum insulation panel was not provided in the space.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings and tables. 1. Hereinafter, a method of preparing a core material in which mica is disposed as a plate-like piece that is a radiation heat shielding member on a glass mat will be described. FIG. 4 is a manufacturing process diagram of the vacuum insulation panel. The manufacturing process diagram shows the concept of the method of manufacturing the core material, and the details of the method will be described below. (1) Adjustment of plate-shaped piece (plate-shaped filler) It is important that the function required for the plate-shaped piece (plate-shaped filler) as the radiation heat shielding member in the present invention is excellent in heat reflection. , A high-density substance such as a metal or an inorganic substance is preferable. It is most preferable to use aluminum foil or mica from the viewpoint of the price reflected from the ease of forming plate-like pieces (flakes). Further, even with a plastic film which is a low-density substance, the same effect can be obtained by coating the surface with a metal thin film such as aluminum. Here, an example using mica in a flake shape will be described. The mica is crushed using a crusher to a size of 0.1 mm or more, preferably 5 to 0.5 mm, more preferably about 2 mm. It is preferable to apply a high-speed water jet by a water jet for the pulverization at this time, since the peeling between the layers is performed at the same time, and a thinner flake-like mica is obtained.

(2) Preparation of Slurry Mica is dispersed in water at a concentration of 10% by weight or less, preferably 0.1 to 5% by weight, more preferably 0.5 to 3% by weight in water with stirring. The intensity of the stirring at this time is, of course, that the mica does not settle and the concentration does not become uneven,
In addition, it is preferable to adjust so that the mica pulverization does not progress. Next, microfibrillated cellulose fiber (abbreviation: MFC), which is a binder, is added in an amount of 0.5 to 5% by weight, preferably 1 to 3% by weight, based on the amount of mica to be uniformly dispersed. In this case, the input amount is generally in the form of a high-viscosity slurry in which microfibrillated cellulose fibers are dispersed in water at a concentration of 5 to 10% by weight. It is necessary to. Here, the microfibrillated cellulose fiber was used because the addition of a very small amount fixes the mica to each other, and the fiber having a diameter of 1 micron or less intervenes between the layers of the mica. Can be suppressed. In addition, many minute spaces formed there block the solid-state heat transfer, so that a more radiant heat insulating effect can be obtained. The effect of suppressing the adhesion of comrades is
By adhering the fine particles as the adhesion suppressant to the mica surface, more effective effects can be obtained by preventing adhesion of the mica and forming a space. The size of the fine particles used at this time is preferably 100 microns or less, more preferably 10 microns or less. Finally, the coagulant is added in an amount of 0.01 to 1% by weight, preferably 0.05%, based on the amount of mica added.
０．２0.2 wt%. By adding this flocculant,
As a result, the ends of the microfibrillated cellulose fibers are sufficiently bonded to the surface of the mica, and the fixation between the mica and the glass fibers can be further strengthened. As a flocculant, acrylamide is generally and most preferable, but in addition, polyethyleneimine, chito acid,
Starch etc. can be used. If microfibrillated cellulose fibers are not used, the glass mat and the filler such as mica and mica will be insufficiently fixed, and the complex between the glass mat and the mica will be immediately decomposed. Only very poor ones can be obtained. Further, if no coagulant is used, the bonding between the microfibrillated cellulose fibers in the slurry liquid and the glass mat and the particles such as mica and silica becomes insufficient, so that the fixing of the filler is not possible. There arises a problem that only a sufficient and non-uniform product can be obtained.

(3) Preparation of slurry liquid A glass mat having a thickness of 20 mm or less, preferably 10 mm or less, more preferably 2 to 5 mm when a compressive load of 1 kg / cm 2 is applied. Used, and the dimensional change rate with respect to the apparent thickness is 1/20 or more, preferably 1/20.
Select one with a density of about 5. As shown in FIG. 5, a slurry liquid 6 in which mica or the like is dispersed is put on a glass mat arranged at the bottom of a cylindrical container 9 as shown in FIG. 5, and the mica settles and the upper part of the liquid becomes transparent. After standing for 1 to 3 minutes, the complex is disposed on the glass mat 5 in parallel with the mica by draining from the drain 8 at the bottom of the container. At this time, if the drainage is forcibly performed using a vacuum pump or the like, efficient drainage with a small amount of residual water can be achieved in a short period of time, and only the mica with a small diameter accumulates on the upper part, and it is easy to peel off. Can be prevented. In the manufacturing process of FIG. 4, the complex was obtained by forming the slurry shown in FIG. 5, but the same effect can be obtained by spraying a slurry on which plate-like pieces are uniformly dispersed on a glass wool mat. .

(4) Drying The obtained complex is left in a high-temperature atmosphere to sufficiently remove water in order to stabilize the quality in the subsequent steps. The drying temperature at this time is 150 ° C. or less, preferably 100 to 12 ° C., at which the bonding strength of the microfibrillated cellulose fiber to the mica and the glass fiber cannot be deteriorated.
After drying in an atmosphere of 0 ° C and pasting it on the surface of a rotating drum that can reduce the bulk density of the complex by compression, it is used for fixing to prevent the sample from falling due to the initial weight of drying. It is effective to use a Yankee dryer that passes between belts and rolls. In addition to this, it is also effective to use a drying oven or to use it together.

(5) Impregnation of Resin The dried complex is immersed in a solution of a thermosetting resin, pulled up, dripped and removed a sufficient amount of the resin, and further dried to remove the solvent of the resin. Let it. At this time, the thermosetting resin to be used is most preferably an epoxy resin capable of controlling a semi-cured state of melting at the time of molding, and it is also possible to use polyester or polyimide. It is also effective to use a thermoplastic resin instead of a thermosetting resin. On the other hand, the amount of resin to be impregnated is important to prevent the vacuum degassing from being hindered by completely covering the glass fiber or mica deposited layer surface after compression-curing molding, but on the other hand, deformation by compression It is also necessary to secure an amount that can maintain the above, so that the range is limited. The amount of the resin to be impregnated is preferably 1 to 20% by weight, more preferably 5 to 10% by weight, based on the weight of the complex. The amount of the resin to be impregnated is adjusted empirically according to the resin concentration in the resin liquid and the viscosity of the resin liquid.

(6) Compression-Curing Molding The complex impregnated with the resin in a semi-cured state is cured under a curing condition suitable for the reaction of the resin, that is, a temperature and a time, and further a board is sandwiched between hot plates holding a constant pressure. Molded into a shape.
The curing conditions at this time vary depending on the type of the resin, but in the case of an epoxy resin, the curing is adjusted at 120 to 180 ° C. within one hour, that is, the molding is completed. The most important thing in this process is the compressive force, which needs to increase the chance of point-to-point contact between the fibers by compression to enhance solidification.
As the amount of solid components such as glass, mica, and resin increases, the heat insulating property is greatly reduced. For this reason, the range of the compressive load is limited, preferably 0.5 to 3 kg / cm2, and 0.8 to 3 kg / cm2.
More preferably, it is 1.5 kg / cm2. As a core material to be a sample, a compression-molded article prepared by stacking and adjusting a plurality of resin-impregnated complex bodies to obtain a predetermined thickness was used.

2. Method for Forming Vacuum Insulated Panel A method for forming the vacuum insulated panel will be described with reference to the manufacturing process diagram of FIG. After inserting the core material into the packaging material heat-sealed in three directions in advance, the remaining one direction is heat-sealed in an atmosphere of a predetermined degree of vacuum using the apparatus shown in FIG.
The vacuum insulation panel having the internal structure shown in FIG. At this time, a thermoplastic resin that can be thermally welded is used for the sealing surface of the packaging material, and a metal foil such as an aluminum foil for completely blocking the invasion of outside air is used for the intermediate layer. Is made of a resin that is resistant to scratches and the like. Thus, it is preferable to use not a single film but a multilayer sheet composed of three or more layers. The sample was prepared by cutting the core material to obtain a predetermined size.

2. Evaluation Method The core material was evaluated using the vacuum heat insulating panel obtained as described above, with respect to heat insulating performance and characteristics including temporal changes in shape. The vacuum insulation panel used as the sample is a core material whose thickness has been adjusted to 20 mm and its surface size has been adjusted to 180 * 180 mm. Nylon, aluminum foil, polyester, and the upper and lower surfaces of the aluminum foil have polyester as the packaging material. A five-layer sheet composed of an adhesive was used. The degree of vacuum in the vacuum insulation panel was set to an arbitrary value between 101 and 10 -3 Torr, and the evaluation of the insulation performance was performed based on the thermal conductivity using “Auto Lambda” manufactured by Eiko Seiki Co., Ltd.

[0027]

【Example】

Embodiment 1 FIG. Hereinafter, results of confirming the effect of improving the heat insulating performance of specific examples of the embodiment of the present invention will be described.
First, Table 1 shows the composition of main components of a prepreg obtained by applying an adhesive to a complex of a glass mat and a plate-like filler.

[0028]

[Table 1]

Using the apparatus shown in FIG. 5, a slurry liquid in which MFC and a small amount of acrylamide are dispersed on a mica or aluminum foil as a plate-like filler is placed on a glass mat, and is left for 5 minutes. The complex of the glass mat and the plate-like filler that was removed and made into a glass mat was placed in an oven at 100 ° C x 20.
It was dried under the condition of minutes. The thickness of the glass mat used here was selected to be 5 mm under a load of 1 kg / cm2. The flake mica has an average diameter of 3 mm, the aluminum foil has a thickness of 20 μm and is cut to an average diameter of 5 mm, and the silica particles used for preventing adhesion have an average diameter of 5 μm.

The complex of the glass mat and the plate-like filler obtained by the above method is impregnated with bisphenol A and epichlorohydrin, which are resin raw materials, in an epoxy resin liquid using methylcellosolve as a solvent, and then is put on a net. The excess epoxy resin liquid was dropped by leaving it to stand for about 30 minutes. Thereafter, by heating and drying in an oven at 125 ° C. for 1 hour, the epoxy resin polymer in a semi-cured state due to the removal of the solvent and the progress of the reaction was coated on the surface of the glass mat fiber and the plate-like filler. I got a prepreg.

After the above prepreg is cut into a size of 180 × 180 mm, four prepregs are placed in a flat plate mold having the same size in an overlapping manner in a mold, and are placed at 120 ° C. at 10-1 To
After leaving for 10 minutes in a vacuum atmosphere of rr, the temperature was raised to 180 ° C. under pressure for 10 minutes, completely cured by leaving for 40 minutes, and cooled to around room temperature. Was. At this time, the load applied to the prepreg was 1.2 kg / cm2 including the weight of the mold.

Using the core material obtained by the above method,
A vacuum insulation panel was prepared in which the inside of the packaging material had an arbitrary degree of vacuum between 101 and 10-3 Torr, and the thermal conductivity of the panel was measured. From the obtained relationship curve between the degree of vacuum and the thermal conductivity as shown in FIG. 8, the thermal conductivity at a degree of vacuum corresponding to 0.1 Torr and the critical vacuum at which the thermal conductivity rapidly increases were obtained. Are shown in Table 2. On the other hand, deformation of the vacuum insulation panel due to atmospheric pressure was visually confirmed.

Also, a vacuum heat insulating panel using a glass mat alone and a communicating rigid polyurethane foam as a core material corresponding to a conventional product is shown as a comparative sample 1 and a comparative sample 2 as a conventional product. The communicating rigid polyurethane foam shown as Comparative Sample 2 has a structure in which the cell membrane for forming air bubbles has holes so that the air remaining inside can be easily exhausted. The vacuum insulation panel used for the material is currently used for refrigerators and the like.

[0034]

[Table 2]

From the above results, it is found that Samples 1 to 5 according to the present embodiment
It is apparent that the vacuum insulation panel of No. 4 has significantly improved heat insulation performance indicated by the thermal conductivity as compared with the glass mat alone and the communicating rigid polyurethane foam shown as comparative samples corresponding to conventional products. is there.

Further, since the critical vacuum degree is higher than that of the conventional product, it has excellent resistance to deterioration of heat insulation performance caused by a decrease in vacuum degree due to gas or the like entering the vacuum heat insulation panel system through a packaging material or the like. It can be said that there is. Furthermore, it has a practically sufficient suppressing force against deformation.

Although the mechanism for lowering the thermal conductivity of the core material by the above method is not clear, it is presumed to have the following factors. The glass mat is composed of glass fibers of several millimeters to several tens of millimeters length deposited almost in the plane direction, and has an irregularly entangled structure. The feature is that the void can be secured. Thereby, the weight reduction can be ensured, and the contact portion between the fibers can be suppressed to a small area, so that the heat transfer perpendicular to the plane direction can be suppressed, and the heat insulating effect can be obtained.

On the other hand, a plate-like substance having an excellent radiation heat shielding effect is laminated so that the particles do not come into direct contact with each other due to fine particles or the like, thereby forming a complex structure such as a layered structure on a glass mat. Insulation of radiant heat can be effectively secured. Moreover, even if the plate-like substance is larger than the heat transfer coefficient of the glass mat, it is an extremely thin layer, so that heat transmitted through the plate-like substance in the thickness direction hardly affects the heat insulation effect. As a result, compared to the case where only the conventional glass mat was used as the core material, the decrease in the amount of radiant heat transfer was significantly greater than the increase in heat transfer due to the arrangement of the plate-like material, so that it was used for vacuum insulation panels. It is presumed that the improved heat insulation performance can be achieved.

Embodiment 2 FIG. Next, the effect of using both the plate-like filler and the fine particles was confirmed. Table 3 shows the composition of the main components.

[0040]

[Table 3]

A slurry liquid obtained by mixing and dispersing microparticles of silica and microfibrillated cellulose fibers, which is used to prevent adhesion between mica, which is a plate-like filler, and mica is used.
Using a device shown in FIG. 5, the material was sprayed on a glass mat having a thickness of 5 mm under a load of 1 kg / cm 2, and excess water was forcibly removed from the lower portion to remove the water. The flake mica used herein has an average diameter of 3 mm, and the silica particles have an average particle diameter of 10 μm. The glass mat thus obtained was left in an oven under drying conditions of 100 ° C. for 20 minutes to completely remove water, and this and the complex of the plate-like filler were converted into bisphenol A and epichlorohydrin as resin raw materials. After impregnating with an epoxy resin liquid using methylcellosolve as a solvent, excess epoxy resin liquid was dropped on the net by leaving it for about 30 minutes. Thereafter, by heating and drying in an oven at 125 ° C. for one hour, a prepreg was obtained in which the surface of the glass mat fiber and the plate-like filler were coated with a semi-cured polymer due to the removal of the solvent and the progress of the reaction.

After the above prepreg is cut into a size of 180 × 180 mm, four prepregs are stacked and placed in a plate mold having the same size, and the prepreg is cut at 120 ° C. under a vacuum atmosphere of 10 -1 Torr. After standing for minutes, the temperature is raised to 180 ° C in 10 minutes,
Further, after being completely cured by leaving for 40 minutes, the temperature was lowered to around room temperature, and then taken out. At this time, the load applied to the prepreg was 1.2 kg / cm2 including the weight of the mold.

Using the core material obtained by the above-described method, a vacuum insulation panel was prepared at an arbitrary degree of vacuum of 101 to 10 -3 Torr inside the packaging material, and after leaving it at room temperature for 5 days, the thermal conductivity was measured. From the obtained relationship curve between the degree of vacuum and the thermal conductivity, the thermal conductivity at a degree of vacuum corresponding to 0.1 Torr and the critical vacuum at which the thermal conductivity rapidly increased were determined. Table 4 shows the results.
Shown in Further, Comparative Sample 3 and Comparative Sample 3 were used without silica particles fixed between the layers of mica and serving to prevent the mica being a plate-like filler from adhering to each other, and having the same composition as that of the mica. This is shown in Comparative Sample 4.

[0044]

[Table 4]

From the above results, the effects of using silica particles, which are fine particles, in combination with mica, which is a plate-like filler, in the core material of the vacuum insulation panel according to the present embodiment were shown in Samples 4 to 7. Although there is no difference in the effect of the silica fine particles in this addition range, when compared with Comparative Sample 3 using only mica shown as a comparative example, although there is no difference in the critical vacuum degree,
The heat insulation performance indicated by thermal conductivity is significantly better. This is considered to be due to the fact that the plate-like fillers adhere to each other and act as a single layer, confirming the effectiveness of fixing the fine particles between the layers of the plate-like filler and providing voids.

On the other hand, the excessive addition of the plate-like filler
In comparison with the above, it was confirmed that there was no difference in the critical vacuum degree due to the addition of 25 parts of silica fine particles, but a decrease in the heat insulation performance indicated by the thermal conductivity was observed. this is,
The excess amount of silica fine particles aggregates, and the space created by the aggregation is covered with epoxy resin to form an independent space. The solvent remaining in this space, such as methylcellosolve or air, is later vacuum-insulated. It is predicted that this is due to a factor that lowers the degree of vacuum in the panel.

Embodiment 3 FIG. Next, the effect of the load applied during compression molding of the prepreg was confirmed. Sample 4 shown in Tables 1 and 3 was used as a main component. The preparation of the prepreg was performed in the same manner as the contents described in the first and second embodiments. In other words, the epoxy resin liquid impregnates the complex body, which is placed on a glass mat with a thickness of 5 mm under a load of 1 kg / cm2, with the flake-like mica adhered to the surface, and then polymerized in a semi-cured state by heating and drying. Is coated on the surface of glass mat fiber and mica which is a plate-like filler. 1 prepreg
After cutting to a size of 80 × 180 mm, four plates were placed in a flat plate mold and left at 120 ° C. in a vacuum atmosphere of 10 -1 Torr for 10 minutes, and an arbitrary load was applied to 180 ° C.
After raising the temperature for 10 minutes, holding for another 40 minutes and completely curing, the temperature was lowered to around room temperature and taken out to prepare a core material of a vacuum heat insulating panel.

At this time, the load applied to the prepreg is preferably in the range of 0.7 to 1.5 kg / cm 2 including the weight of the mold, and the load applied to the prepreg is 0.5 kg / cm 2 lower than the preferable range. Contrary to that of the above, a core material of 1.8 kg / cm2, which is higher than that of
Vacuum insulation panels were prepared at an arbitrary degree of vacuum of 10 to 3 Torr, and the thermal conductivity of the panels was measured. From the relationship curve between the degree of vacuum and the thermal conductivity, the thermal conductivity at a vacuum degree equivalent to 0.1 Torr and the critical vacuum degree at which the thermal conductivity rises sharply are determined, and the results are compared with Samples 4 and 8 to 10. Table 5 also shows samples 5 and 6. On the other hand, deformation due to atmospheric pressure was visually confirmed.

[0049]

[Table 5]

From the above results, the difference in the compression molding load applied to the molding of the core material of the vacuum insulation panel is due to the influence of the compression molding load in the range of 0.7 to 1.5 kg / cm 2 shown in Samples 8 to 10. No difference in thermal conductivity and critical vacuum. However, with the low compression molding load shown as Comparative Sample 5, although it was equivalent to the critical vacuum degree and the thermal conductivity as an index of heat insulation performance, a deformation that impaired the design when mounted in a refrigerator or the like was confirmed.

On the contrary, it was confirmed that the heat conductivity was significantly increased and the heat insulation performance was inferior, though there was no deformation under the high compressive load shown as Comparative Sample 6.

In this case, the space between the fillers becomes unnecessarily small, and even if the excess resin partially fills the voids, it forms a closed space. As a result, it is presumed that the solvent remaining in this, such as methylcellosolve or air, acts as a factor that lowers the degree of vacuum in the vacuum insulation panel and deteriorates the thermal conductivity later.

Embodiment 4 FIG. Next, the effect on lamination when forming the core material of the vacuum insulation panel was confirmed. As a main component, sample 4 shown in Tables 1 and 3 was applied. In other words, the mica and silica particles are impregnated with an epoxy resin liquid under a load of 1 kg / cm2 and placed on a glass mat having an arbitrary thickness of 1 to 5 mm, and then heated and dried to obtain a semi-cured state. To obtain a prepreg coated on its surface with a polymer of the formula (1). After cutting this prepreg into 180 × 180 mm, a plurality of pieces were placed in a flat plate mold and left for 10 minutes in a vacuum atmosphere of 10-1 Torr under heating at 120 ° C. With a load of 1.2 kg / cm2 including
The core material of the vacuum insulation panel was prepared by raising the temperature to 0 ° C. in 10 minutes, leaving it for 40 minutes to completely cure it, and then taking it out at a temperature lowered to around room temperature.

At this time, the number of prepregs in which the glass mat and the filler such as mica are complexed in the mold, that is, the number of prepregs to be laminated is preferably 4 to 12, so that Samples 4 and 11 to 13, and Sample 7 and comparative sample 8 also have two prepregs, which are smaller than the preferable number of layers, and 19 sheets which are excessively stacked.
Using the core material obtained as above, the inside of the packaging material is 101-10-
A vacuum insulation panel was prepared at an arbitrary degree of vacuum of 3 Torr, and the thermal conductivity of the panel was measured. From the relationship curve between the degree of vacuum and the thermal conductivity, the thermal conductivity at a vacuum of 0.1 Torr and the critical vacuum at which the thermal conductivity rapidly increased were determined. Table 6 shows the results.
It was also described in.

[0055]

[Table 6]

From the above results, Sample 4 and Samples 11 to 13
With the increase in the number of laminated layers of 4 to 12 shown in the above, there was only a tendency that the critical vacuum degree slightly increased, and no difference was observed in the thermal conductivity. However, in Comparative Sample 7 with a small number of laminated layers, a slight decrease in the thermal conductivity and a clear decrease in the critical vacuum were observed. Further, when the number of laminated layers shown as Comparative Sample 8 was too large, although the critical vacuum degree was slightly superior, the thermal conductivity was significantly increased, and a decrease in heat insulation performance was confirmed.

This is because when the mica as the plate-like filler is molded under vacuum, the solvent or air remaining in the core material is not easily discharged, and these residual gases form a vacuum insulation panel. It is predicted that the degree of vacuum in the system was reduced with time over time, thereby causing a deterioration in thermal conductivity.

Embodiment 5 FIG. Next, the operation performance of the refrigerator using the vacuum heat insulating material of the present invention was measured, and the effect was confirmed. First, using a vacuum insulating panel produced by the same method as in Sample 4 shown in Example 1 using a packaging material having an aluminum foil in the intermediate layer, vacuum molding ABS resin into an outer box obtained by bending a thin steel plate. As shown in FIG. 3, a total of six sheets of the ceiling surface, the left and right side surfaces of the freezing room and the refrigerator room, and the rear surface are attached to the outer box side in the gap formed by fitting the inner box obtained by the above. Thereafter, rigid urethane foam was injected, foamed, and filled into the remaining voids to completely fix them.

A refrigerant circuit and the like were arranged using the heat-insulating box produced by the above method, and a 400-liter class refrigerator was assembled. This was used as a prototype refrigerator. On the other hand, a refrigerator using a heat-insulating box made in the same manner using a vacuum heat-insulating panel using a hard urethane foam as a core and communicating with a core produced by the same method as Comparative Sample 2 shown in Example 1 was used. The comparative refrigerator 1 and the insulated box in which all the gaps between the inner box and the outer box were filled with rigid urethane foam were referred to as the comparative refrigerator 2, and all these refrigerators consumed power in accordance with the power consumption B method measurement method in JIS-C9607. And the results are shown in Table 7.

[0060]

[Table 7]

From the above results, the refrigerator in which the vacuum insulation panel having the core material of the structure in which the flake mica is laminated on the glass mat according to the present invention is provided is a comparative refrigerator using only rigid urethane foam as the insulation material. Not only does it exhibit much lower power consumption compared to 2, but also superior to the comparative refrigerator 1 using a vacuum insulation panel with a hard urethane foam as the core material of the commonly used open-air method. It was found that the power consumption was excellent.

This is based on the fact that the heat insulation performance of the vacuum heat insulation panel of the present invention is significantly superior to that of the conventional vacuum heat insulation panel, as shown in Example 1.

As described above, the structure of the vacuum heat insulating panel simulating the application to the refrigerator, the composition for obtaining the same, the thermal conductivity as an index of the heat insulating property of the embodiment relating to the manufacturing method thereof, and the stable heat insulating performance are secured. The critical vacuum degree that could be achieved and the presence or absence of external deformation were evaluated. As a result, a conventional glass mat or a vacuum insulation panel using open-celled rigid polyurethane foam as the core material, and a glass mat according to the present invention laminated with a plate-like filler excellent in heat reflection properties and then impregnated with a resin By applying the solidified complex structure to the core material, it can be said that it is suitable for use as a heat insulating material for refrigerators and the like in terms of excellent heat insulating properties and suppressing deformation of the exterior surface.

Embodiment 2 In the first embodiment described above, the refrigerator and the door using the vacuum insulation panel for the door and the like are shown as examples. However, the present invention is not limited to the refrigerator. For example, a small refrigerator for a vehicle or a simple prefabricated refrigerator, It can also be applied as a component of heat insulation and / or cold insulation products, such as cold insulation vehicles, pipes, and insulation materials for buildings.
Various modifications can be made without departing from the scope of the invention.

[0065]

As described above, according to the vacuum heat insulating panel of the present invention, the radiation heat shielding member laminated on the glass wool mat has the effect of reducing the radiation heat transfer. Further, mica flakes and metal foils are easy to form plate-like pieces. Further, by adding the adhesion suppressant to the surface of the plate-like pieces, the adhesion between the plate-like pieces is suppressed and reduced, and the heat insulation performance is improved. Further, since the core material of the vacuum insulation panel of the present invention is formed by curing the complex impregnated with the resin while applying a constant pressing force, even if the inside of the vacuum insulation panel is evacuated, the packaging material The inside does not deform during use. Further, the plate-shaped piece can be easily disposed on the glass wool mat simply by forming a slurry liquid in which the plate-shaped piece is uniformly dispersed on a glass wool mat. Further, the plate-shaped piece can be easily arranged on the glass wool mat simply by spraying the slurry liquid containing the plate-shaped piece on the glass wool mat. In addition, since the slurry liquid is easily captured on the glass wool by the coagulant and the binder, and can be fixed by the binder, the slurry can be stably held without being peeled off even by resin impregnation. Easy to handle. Further, a refrigerator using the vacuum heat insulating panel of the present invention as a heat insulating material is a refrigerator provided with a vacuum heat insulating panel using only a conventional hard urethane foam as a heat insulating material and further using urethane foam having open cells as a core material. The power consumption is significantly lower than that of, and the heat insulation is excellent. Further, since the remaining space in the gap is held by the hard urethane foam, it is firmly fixed, and an appearance similar to that of a conventional refrigerator can be secured.

[Brief description of the drawings]

FIG. 1 is a comparison diagram of the heat insulating performance of each heat insulating material.

FIG. 2 is a manufacturing process diagram of a refrigerator equipped with a vacuum insulation panel.

FIG. 3 is an arrangement diagram of a vacuum heat insulating panel in a cross section of a refrigerator.

FIG. 4 is a manufacturing process diagram of the vacuum heat insulating panel of the present invention.

FIG. 5 is a conceptual diagram of a papermaking apparatus for disposing a plate-like substance of the present invention on a glass mat.

FIG. 6 is a conceptual diagram of a vacuum heat insulating panel manufacturing apparatus for fusing the edges in a vacuum atmosphere.

FIG. 7 is a sectional view of a vacuum heat insulating panel.

FIG. 8 is a graph showing an example of the relationship between the degree of vacuum and the thermal conductivity.

[Explanation of symbols]

1 outer box of refrigerator, 2 inner box of refrigerator, 3 vacuum insulation panel, 4 rigid polyurethane foam, 5 glass mat, 6 slurry liquid, 7 drain liquid, 8 drain drain (wire mesh), 9 cylindrical container, 11 vacuum Panel forming machine, 1
4 Packaging material, 15 core material.

Claims (18)

[Claims] 1. A packaging material having a function of forming an outer shell, blocking the invasion of outside air and maintaining the inside of the packaging material at a vacuum, and being housed in the packaging material, maintaining the shape of the packaging material, and forming a glass wool mat. A vacuum heat insulating panel, comprising: a core member formed of a complex body on which a radiant heat shielding member excellent in radiant heat shielding effect is laminated. 2. The vacuum heat insulating panel according to claim 1, wherein the glass wool mat is formed by depositing glass wool in a plane direction perpendicular to a heat insulating direction. 3. The vacuum heat insulating panel according to claim 1, wherein the radiation heat shielding member is formed of a plate-like piece. 4. The vacuum heat insulating panel according to claim 3, wherein the plate-like piece is formed of mica flake. 5. The vacuum heat insulating panel according to claim 3, wherein the plate-like piece is made of a metal foil. 6. The vacuum heat insulating panel according to claim 3, wherein said plate-like piece is formed by coating a plastic film with a metal thin film. 7. The vacuum heat insulating panel according to claim 3, wherein the plate-like piece contains an adhesion suppressing agent for suppressing adhesion. 8. A complex forming step of arranging a plate-like piece on a glass wool mat to form a complex, a drying step of removing moisture of the complex obtained in the complex forming step, An impregnation step of immersing the complex dried in the drying step in a resin solution; and compression-hardening molding by curing the complex impregnated with the resin in the impregnation step while applying a constant pressure. And a method for manufacturing a core material of a vacuum heat insulating panel. 9. The manufacturing of a core material of a vacuum heat insulating panel according to claim 8, wherein in the complex forming step, a slurry liquid in which the plate-like pieces are uniformly dispersed is made up with the glass wool mat. Method. 10. The production of a core material for a vacuum insulation panel according to claim 8, wherein in the complex forming step, a slurry liquid in which the plate-like pieces are uniformly dispersed is sprayed on the glass wool mat. Method. 11. The bonding material according to claim 1, wherein the slurry liquid fixes the plate-like pieces together and suppresses the close contact between the plate-like pieces;
The method for manufacturing a core material for a vacuum insulation panel according to claim 9, further comprising a coagulant for facilitating the binding of a part of the binder to the surface of the glass wool mat. 12. The method according to claim 11, wherein the coagulant is acrylamide. 13. The method according to claim 11, wherein the binder is a microfibrillated cellulose fiber. 14. The method according to claim 8, wherein the resin in the impregnation step is a thermosetting resin or a thermoplastic resin in a semi-cured state. 15. The core of a vacuum heat insulating panel according to claim 8, wherein in the compression-hardening molding step, 4 to 12 layers of the complex impregnated with the resin in the impregnation step are laminated and molded. The method of manufacturing the material. 16. The method for producing a core material of a vacuum heat insulating panel according to claim 8, wherein a pressure is 0.7 to 1.5 kg / cm 2 in the compression hardening molding step. 17. An outer box made by bending a thin steel plate, an inner box made by molding resin, a gap formed by fitting the outer box and the inner box,
A refrigerator, wherein the vacuum heat insulating panel according to claim 1 is disposed in the gap portion and used as a heat insulating material. 18. The vacuum insulation panel is attached to the inner box or the outer box of the gap, and the other gap of the gap is filled with a rigid polyurethane foam and held. The refrigerator according to claim 17, wherein