JP2022124435A - Vacuum heat insulation panel and method for manufacturing the same - Google Patents

Abstract

To provide a vacuum heat insulation panel having lower thermal conductivity than before, and a method for manufacturing the same.SOLUTION: In a vacuum heat insulation panel according to the present invention, an internal space is formed by a pair of metal plates of which principal surfaces are arranged so as to face each other at a predetermined interval, and a glass sealing part sealing peripheral edge regions of the pair of metal plates with a glass sealing material. The internal space is in a high vacuum state. In the internal space, spacers for keeping the predetermined interval are dispersedly arranged in a plane lattice form. In the glass sealing part, a sealing part reinforcing member for reinforcing the glass sealing part is inserted via the glass sealing material.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to the art of insulation, and more particularly to vacuum insulation panels and methods of manufacturing the same.

A heat insulator called a vacuum insulation panel (VIP) is widely used as a heat insulator for refrigerating, freezing, and heat-retaining devices and containers. Vacuum insulation panels, which are currently the mainstream, are made by vacuum-packing the insulation material with an outer wrapping material consisting of a multi-layered metal/resin sheet. ing.

As an example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2002-130583), a spacer (such as glass fiber, ceramic fiber, etc.) having substantially the same shape as the space is placed in a substantially flat space formed inside a metal plate-like body. A method for manufacturing a vacuum insulator, characterized by arranging a woven or nonwoven fabric), sealing the inside, forming it into a desired shape, and then evacuating the internal space through an exhaust part. ing.

According to Patent Document 1, by arranging spacers in the internal space of a metal plate, it becomes possible to form a vacuum space over the entire region of a desired shape, thereby exhibiting desired heat insulation performance. It is said that it can be done.

Patent Document 2 (Japanese Patent Laid-Open No. 2007-182991) describes a vacuum heat insulating material in which a core material made of glass fiber is vacuum-sealed with an outer wrapping material having gas barrier properties, wherein the glass fiber contains 5 to 5 B ₂ O ₃ . 12% by weight, 0 to 7% by weight of Al ₂ O ₃ , 2 to 11% by weight of CaO, and 8 to 20% by weight of the total of Na ₂ O and K ₂ O. discloses a vacuum insulation material characterized by having a Young's modulus of 77.8 GPa or more.

According to Patent Document 2, by increasing the strength of the glass material itself used as the core material of the vacuum heat insulating material, the amount of deformation of the core material due to the atmospheric compressive stress after decompression sealing is reduced to suppress densification. As a result, it is said that the heat conduction of the solid component of the core material can be reduced and the heat insulating performance of the vacuum heat insulating material can be improved.

In addition, Patent Document 3 (Japanese Patent Application Laid-Open No. 2020-133655) describes a first heating step in which an inorganic heat insulating material is heated to remove bound water in the heat insulating material, and a second heating step in which one is provided with an opening for exhaust. a heat insulating material placement step of placing the heat insulating material between a first metal plate and a second metal plate; A welding step of manufacturing a pre-evacuation panel by welding, a second heating step of heating the pre-evacuation panel to remove moisture attached to the pre-evacuation panel, and an internal space of the pre-evacuation panel , a method for manufacturing a vacuum insulation panel, including a vacuum drawing step of drawing a vacuum through the opening, and a sealing step of closing the opening with a sealing material.

According to Patent Document 3, it is possible to provide a method for manufacturing a vacuum insulation panel having excellent insulation performance even at high temperatures (for example, 300° C. or higher), and the vacuum insulation panel.

Patent Documents 4 and 5 will be described later.

Japanese Patent Application Laid-Open No. 2002-130583 JP 2007-182991 A JP 2020-133655 A JP 2013-032255 A WO2017/126378

In recent years, there is a growing trend toward global environmental protection such as energy saving and resource saving. Conventional vacuum insulation panels have a thermal conductivity of about 2 mW/(m K) at room temperature, while the thermal conductivity of typical conventional insulation materials (for example, the thermal conductivity of rigid urethane foam: about 24 mW/(m・K), thermal conductivity of high-performance phenolic foam: approx. can be said to have contributed significantly to

Here, if it is possible to develop an insulator with lower thermal conductivity than conventional vacuum insulation panels, it will be possible to further improve the energy-saving performance of refrigeration, freezing, and heat retention equipment and containers, and heat transmission as an insulator. It is also possible to reduce the thickness of the insulation without compromising the coefficient/heat transmittance. If the insulation can be made thinner, it becomes possible to increase the space/volume for refrigerating/freezing/heat-retaining without changing the external dimensions of the device/container.

In conventional vacuum insulation panels, each of the constituent materials (e.g., metal sheets, resin sheets, glass fibers, ceramic fibers, etc.) is in principle recyclable, but the recycling cost is the sales price of used materials. (including transportation cost), unfortunately it is not a valuable resource and is now a waste. From the viewpoint of resource saving and effective use of resources, it is preferable that the vacuum insulation panel be configured as a valuable resource.

SUMMARY OF THE INVENTION Accordingly, it is a primary object of the present invention to provide a vacuum insulation panel with lower thermal conductivity than conventional ones and a method for manufacturing the same. A secondary object of the present invention is to provide a vacuum insulation panel that is more recyclable than conventional ones.

(I) One aspect of the present invention is a vacuum insulation panel,
An internal space is formed by a pair of metal plates whose main surfaces face each other with a predetermined gap, and a glass sealing portion obtained by sealing the peripheral edge region of the pair of metal plates with a glass sealing material. The space is in a high vacuum state,
In the internal space, spacers for maintaining the predetermined spacing are distributed in the form of a planar lattice,
A sealing portion reinforcing member for reinforcing the glass sealing portion is inserted through the glass sealing material in the glass sealing portion,
To provide a vacuum insulation panel characterized by:

(II) Another aspect of the present invention is a method for manufacturing the above vacuum insulation panel,
a first insulating plate preparing step of preparing a first insulating plate by building up and applying the glass sealing material to the peripheral edge region of one main surface of one of the pair of metal plates and pre-baking it;
a second heat insulating plate preparing step of preparing a second heat insulating plate to face the first heat insulating plate;
The first heat insulating plate and the second heat insulating plate are arranged facing each other so that the surface of the first heat insulating plate to which the glass sealing material is calcined faces the inside, and the softening point of the glass sealing material is -10°C. and a step of forming the glass sealing portion by raising the temperature to a temperature equal to or higher than the softening point +20° C. and sealing the first insulating plate and the second insulating plate to form the glass sealing portion. have
The step of preparing the first insulating plate includes:
a sealing portion reinforcing member inserting step of inserting the sealing portion reinforcing member in the build-up application portion after the build-up application of the glass sealing material;
a spacer dispersing and arranging step of applying the adhesive in the form of the planar lattice to the region corresponding to the internal space and then adhering and arranging the spacers while rolling the spacers;
To provide a method for manufacturing a vacuum insulation panel characterized by:

(III) Another aspect of the present invention is a method for manufacturing the above vacuum insulation panel,
a first insulating plate preparing step of preparing a first insulating plate by building up and applying the glass sealing material to the peripheral edge region of one main surface of one of the pair of metal plates and pre-baking it;
a second heat insulating plate preparing step of preparing a second heat insulating plate to face the first heat insulating plate;
The first heat insulating plate and the second heat insulating plate are arranged facing each other so that the surface of the first heat insulating plate to which the glass sealing material is calcined faces the inside, and the softening point of the glass sealing material is -10°C. a glass sealing portion forming step of forming the glass sealing portion by increasing the temperature to a temperature of the softening point +20 ° C. or less and sealing the first insulating plate and the second insulating plate to form the glass sealing portion;
While evacuating the internal space from an exhaust port formed in at least one of the pair of metal plates, the softening point of the other glass sealing material having a softening point lower than that of the glass sealing material by 50°C or more is equal to or higher than the softening point of the other glass sealing material. An exhaust port vacuum sealing step of raising the temperature to a softening point +20 ° C. or less, and vacuum-sealing the exhaust port using a metal lid that closes the exhaust port and the other glass sealing material. ,
The step of preparing the first insulating plate includes:
a sealing portion reinforcing member inserting step of inserting the sealing portion reinforcing member in the build-up application portion after the build-up application of the glass sealing material;
a spacer dispersing and arranging step of applying the adhesive in the form of the planar lattice to the region corresponding to the internal space and then adhering and arranging the spacers while rolling the spacers;
To provide a method for manufacturing a vacuum insulation panel characterized by:

According to the present invention, it is possible to provide a vacuum insulation panel with lower thermal conductivity than conventional ones and a method for manufacturing the same. By using the vacuum insulation panel according to the present invention, the thickness of the heat insulator can be reduced without deteriorating the heat transmission coefficient/heat transmittance of the heat insulator. In addition, as a secondary effect, the vacuum insulation panel according to the present invention does not use heat insulation materials with high recycling costs (for example, glass fiber, ceramic fiber, plastic foam, etc.), so recyclability is higher than before. it is conceivable that.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view taken along the line A-A' and a schematic plane transparent view showing an example of a vacuum heat insulating panel according to the present invention; It is a cross-sectional schematic diagram which shows an example of the vicinity of the glass sealing part by which the sealing part reinforcement member was inserted. It is a cross-sectional schematic diagram which shows the modification of FIG. 2A. It is a cross-sectional schematic diagram which shows another example of the vicinity of the glass sealing part by which the sealing part reinforcement member was inserted. FIG. 9 is a schematic cross-sectional view showing still another example of the vicinity of the glass sealing portion in which the sealing portion reinforcing member is inserted. 1 is a flowchart showing an example of a method for manufacturing a vacuum insulation panel according to the present invention; FIG. 4 is a graph showing the relationship between elapsed time and thermal conductivity in an accelerated test of the vacuum insulation panel of the present invention using glass powder STA-1 and a conventional vacuum insulation panel filled with glass wool.

The present invention can add the following improvements and changes to the vacuum insulation panel (I) described above.
(i) the glass sealing material is a lead-free glass material having a softening point of 330° C. or less;
The spacer is a sphere or column made of a ceramic material or a resin material,
The sealing portion reinforcing member is made of a metal material, a ceramic material, a metal material/resin material composite, or a metal material/ceramic material composite.
(ii) the glass sealing material consists of three or more kinds of oxides when the components are expressed as oxides;
Containing V ₂ O ₅ (vanadium oxide) and Ag ₂ O (silver oxide) as main components,
containing TeO ₂ (tellurium oxide) and/or Li ₂ O (lithium oxide) as a first optional component,
A group consisting of K2O (potassium oxide), MgO ₍ magnesium oxide), P2O5 ₍ phosphorous oxide), BaO (barium oxide), ZnO (zinc oxide), and WO3 ₍ tungsten oxide) as the _second optional component containing one or more of
_{Al2O3 (} aluminum oxide), _{Fe2O3 (} iron oxide), _Y2O3 (yttrium oxide), _{La2O3 (} lanthanum oxide), CeO2 ₍ cerium oxide), _Er2 as the _third optional component It contains one or more of the group consisting of O ₃ (erbium oxide) and Yb ₂ O ₃ (yttrium oxide).
(iii) The predetermined interval is 0.2 mm or more and 18 mm or less.
(iv) The thickness of the glass sealing material interposed between the sealing portion reinforcing member and the metal plate in the glass sealing portion is 0.01 mm or more and less than 0.2 mm.
(v) the degree of vacuum of the internal space is less than 1×10 ⁻¹ Pa;
(vi) the planar lattice includes one or more of the group consisting of a square lattice, a rectangular lattice, a regular triangular lattice, an orthorhombic lattice and a parallel lattice;
(vii) The metal plate has a thickness of 0.1 mm or more and 1 mm or less.
(viii) The electrical resistivity between the pair of metal plates is 100 kΩ·m or more.
(ix) The thermal conductivity of the vacuum insulation panel at room temperature is less than 2 mW/(m·K).
(x) at least one of the pair of metal plates is formed with an exhaust port for evacuating the internal space;
The vent is sealed with a metal lid that closes the vent and another glass sealing material.
(xi) The other glass sealing material is a lead-free glass material that has a softening point lower than that of the glass sealing material by 50°C or more, and has three or more types of oxidation when the components are expressed as oxides. consist of things
Containing V ₂ O ₅ and Ag ₂ O as main components,
containing TeO ₂ and/or Li ₂ O as a first optional component,
containing at least _one selected from the group consisting of _K2O , MgO, P2O5, BaO _, ZnO, and WO3 as a _second optional component,
containing one or more selected from the group consisting of Al ₂ O ₃ , Fe ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , CeO ₂ , Er ₂ O ₃ and Yb ₂ O ₃ as a third optional component; there is

According to the present invention, the following improvements and changes can be added to the vacuum insulation panel manufacturing methods (II) and (III) described above.
(xii) The step of preparing the second heat insulating plate includes a step of forming a heat reflecting film on the surface of the second heat insulating plate facing the first heat insulating plate.

(Basic idea of the present invention)
As mentioned above, conventional vacuum insulation panels have a thermal conductivity of about 2 mW/(m K) at room temperature, and are comparable to typical conventional insulation materials (e.g. rigid urethane foam, high-performance phenolic foam). It exhibits a low thermal conductivity of 1/10 or less of that of In order to develop a heat insulator with even lower thermal conductivity, the present inventors first investigated and studied the configuration/characteristics of conventional vacuum heat insulating panels.

In conventional vacuum insulation panels, it was thought that the main heat conduction paths/factors were the direct bonding of the outer wrapping materials together in the peripheral area of the panel and the filling of the insulation material as a core material. In addition, if a resin material is used for the outer wrapping material, the gas will permeate the resin material little by little, or the resin material will decompose and release the gas. A weak point was considered to be deterioration and an increase in thermal conductivity.

In addition, conventional vacuum insulation panels have a large weight ratio of the heat insulation material (for example, glass fiber, ceramic fiber, etc.) used as the core material (ratio of the weight of the heat insulation material to the weight of the entire vacuum insulation panel), and the heat insulation material is not a valuable material, it was thought that the vacuum insulation panel as a whole had a weak point of low recyclability.

Therefore, the inventors of the present invention, as a basic policy for developing a heat insulator with a lower thermal conductivity,
a) Do not directly join the outer wrapping materials that constitute the main surfaces of the vacuum insulation panel,
b) Do not fill/fill the internal space to be evacuated with a heat insulating material that serves as a core material;
c) to increase the degree of vacuum in the internal space more than before (high vacuum of less than 1×10 ^-1 Pa);
d) so that the resin material does not face the internal space;
and conducted intensive research.

As a result, the peripheral regions of the pair of metal plates whose main surfaces face each other at a predetermined interval are vacuum-sealed by the glass sealing portion made of the glass sealing material, and the height of the internal space is brought into a high vacuum state. Spherical or columnar spacers are distributed in the internal space in the form of a planar lattice to maintain the distance (the gap between the pair of metal plates), and the sealing portion is reinforced to mechanically reinforce the glass sealing portion. It was found that a vacuum insulation panel with lower thermal conductivity (less than 2 mW/(m·K) at room temperature) can be obtained by adopting a structure in which the member is inserted between the glass-sealed portions. The present invention has been completed based on this finding.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described more specifically with reference to the drawings. However, the present invention is not limited to the embodiments taken up here, and it is possible to appropriately combine with known techniques or improve based on known techniques without departing from the technical idea of the invention. .

{First embodiment}
[Vacuum insulation panel]
FIG. 1 is a schematic cross-sectional view taken along the line AA' and a schematic transparent plane view showing an example of a vacuum insulation panel according to the present invention. Note that the transparent schematic diagram is a schematic diagram in which the opaque body is drawn as a transparent or translucent body in order to show the positional relationship of an object that is originally hidden by the opaque body and cannot be seen directly.

As shown in FIG. 1, a vacuum insulation panel 100 according to the present invention includes a pair of metal plates 10 and 20 whose main surfaces face each other with a predetermined gap. An internal space 40 is formed by sealing with the glass sealing portion 30 used. Spacers 50 are distributed in the internal space 40 in the form of a planar grid to maintain a predetermined spacing. A sealing portion reinforcing member 60 for mechanically reinforcing the glass sealing portion 30 is interposed through a glass sealing material.

At least one of the pair of metal plates 10 and 20 is formed with an exhaust port 70 for evacuating the internal space 40. The exhaust port 70 is made up of a metal lid 80 closing the exhaust port and other glass. It is sealed with a sealing material.

The degree of vacuum in the internal space 40 is preferably less than 1×10 ⁻¹ Pa, more preferably 5×10 ⁻² Pa or less. In the present invention, a vacuum degree of less than 1×10 ⁻¹ Pa is defined as high vacuum. The degree of vacuum of conventional vacuum insulation panels is on the order of 10 ⁰ Pa (1 to 9 Pa), which falls within the category of medium vacuum.

In the vacuum insulation panel 100 according to the present invention, the metal plates 10 and 20, which are outer packaging materials, are not directly joined to each other but are joined through the glass sealing portion 30, and the inner wall formed between the metal plates 10 and 20 Since the space 40 is in a high-vacuum state, it exhibits a lower thermal conductivity (less than 2 mW/(m·K) at room temperature) than conventional ones. As an example, it exhibits extremely excellent low thermal conductivity with a thermal conductivity of 1 mW/(m·K) or less at room temperature (details will be described later). The distance between the metal plates 10 and 20 (the height of the internal space 40) is the heat transmission coefficient/heat transmission coefficient required for the heat insulator (for example, the heat transmission coefficient/heat transmission coefficient of a conventional vacuum insulation panel: 167 mW/ (m ² · K) or less) can be appropriately set within the range of 0.2 mm or more and 18 mm or less.

It should be noted that it is not necessary to achieve the required heat transmission rate/heat transmission rate with only one vacuum insulation panel 100, and the heat transmission rate/heat transmission rate can be reduced by stacking a plurality of vacuum insulation panels 100 in the thickness direction. You can adjust the rate. Further, when a plurality of panels are laminated, a lubricating layer may be inserted between the laminated panels so that each panel can slide to some extent in response to temperature changes and temperature gradients. By allowing the laminated panels to slide, it is possible to suppress warpage of the thermal insulator as a whole even when the thermal gradient of the environment to be thermally insulated is very large.

Next, each component constituting the vacuum insulation panel 100 will be described in more detail.

(metal plate, metal lid)
The metal plates 10 and 20 and the metal lid 80 have rigidity to withstand the surface pressure of the atmospheric pressure (rigidity to the extent that the height of the internal space 40 does not become zero due to the stress caused by the differential pressure between the outside and the internal space 40). It is necessary to use a metal material that has The thicknesses of the metal plates 10 and 20 and the metal lid 80 are preferably 0.1 mm or more from the viewpoint of rigidity and airtightness, and preferably 1 mm or less from the viewpoint of reducing the weight of the vacuum insulation panel 100 .

In addition, although the material cost is low, it is preferable to use a material that has a value as a valuable resource even if it is a used material. As an example, an alloy steel plate, a stainless steel plate, and an aluminum alloy plate can be preferably used. The metal plates 10, 20 and the metal lid 80 may be made of the same metal material, or may be a combination of different metal materials.

The main surface size (length x width) of the metal plates 10 and 20 is not particularly limited, and the size of the heat insulator (refrigeration/freezing/warming device/container size) using the vacuum insulation panel 100 of the present invention can be used as appropriate. Match it. An example is length x width = 1500 mm x 600 mm.

The shape and size of the exhaust port 70 are not particularly limited as long as the internal space 40 can be efficiently evacuated. It is preferable to control so that the width is equal to or less than the width of the stopping portion 30 . Although the position of the exhaust port 70 is not particularly limited, it is more convenient to position it in the vicinity of the glass sealing portion 30 from the viewpoint of manufacturability of the vacuum insulation panel.

(Spacer)
The spacer 50 is used to maintain the height of the internal space 40 (the gap between the pair of metal plates 10 and 20 arranged facing each other). From the viewpoint of suppressing the contact heat transfer amount between the pair of metal plates 10 and 20 as much as possible, the spacers 50 are preferably distributed in the internal space 40 in a planar grid pattern. Moreover, in order to suppress the contact heat transfer amount as much as possible, it is preferable to use a spherical body or a columnar body made of a ceramic material or a resin material having a thermal conductivity lower than that of metal.

When using a resin material as the spacer 50, an engineering plastic (for example, polyimide, polyether ether ketone, polyphenylene sulfide) are preferably used.

There is no particular limitation on the mode of the planar lattices to be dispersedly arranged, and for example, one or more of the group consisting of square lattices, rectangular lattices, equilateral triangular lattices, rhombic lattices and parallel lattices can be appropriately selected. FIG. 1 described above shows an example in which the spherical spacers 50 are distributed in a square lattice manner. The size of the spacer 50 may be appropriately selected according to the desired height of the internal space 40 (desired distance between the pair of metal plates 10 and 20 facing each other), and is preferably 0.2 mm or more and 18 mm or less, for example.

(sealing part reinforcing member)
FIG. 2A is a schematic cross-sectional view showing an example of the vicinity of the glass sealing portion in which the sealing portion reinforcing member is inserted. The example shown in FIG. 2A is a case where the sealing portion reinforcing member 60 is made of a single piece of metal material or ceramic material. As shown in FIG. 2A, the glass sealing portion 30 is formed by inserting a sealing portion reinforcing member 60 between the metal plates 10 and 20 via a predetermined glass sealing material (lead-free glass material having a softening point of 330° C. or less). are interspersed.

The metal material and ceramic material used as the sealing portion reinforcing member 60 are not particularly limited as long as they can be used for vacuum sealing. For example, the same metal material as the metal plates 10 and 20, or ceramic materials such as quartz, alumina, and zirconia can be suitably used. Metal materials are more advantageous than ceramic materials in terms of mechanical properties such as toughness and airtightness, and ceramic materials are more advantageous than metal materials in terms of low thermal conductivity.

Here, as a result of research by the present inventors, cracks occur when the thickness of the glass sealing material interposed between the sealing portion reinforcing member 60 and the metal plates 10 and 20 in the glass sealing portion 30 is 0.2 mm or more. is likely to occur, and the thickness of the glass sealing material is preferably less than 0.2 mm. On the other hand, from the viewpoint of ensuring adhesiveness and airtightness, the thickness of the glass sealing material is preferably 0.02 mm or more. In other words, the thickness of the sealing portion reinforcing member 60 is such that the thickness of the glass sealing material interposed between the metal plates 10 and 20 is 0.02 mm or more and less than 0.2 mm, and the desired height of the internal space 40 is Set so that it can be secured.

The sealing portion reinforcing member 60 is a member for preventing the occurrence of cracks in the glass sealing material in the glass sealing portion 30. If the cracking can be prevented, the sealing portion reinforcing member 60 is used in the glass sealing portion 30. It is not necessary to interpolate all the way around. For example, a plurality of sealing portion reinforcing members 60 may be inserted so as to divide the entire circumference of the glass sealing portion 30 into a plurality of locations, or an appropriate spacing may be provided between adjacent sealing portion reinforcing members 60. may be empty.

FIG. 2B is a schematic cross-sectional view showing a modification of FIG. 2A. In the glass sealing portion 30 shown in FIG. 2B, the sealing portion reinforcing member 60 does not penetrate the glass sealing material in the in-plane direction of the metal plates 10 and 20, and the internal space 40 of the sealing portion reinforcing member 60 does not penetrate. It differs from FIG. 2A in that the portion on the facing side is covered with a glass sealing material, otherwise the same.

(Glass sealing material, other glass sealing material)
The glass sealing material used in the glass sealing part 30 and other glass sealing material for sealing the metal lid 80 have a softening point of 330° C. or less from the viewpoint of reducing the environmental load and manufacturability of the vacuum insulation panel. of low melting point lead-free glass materials are preferred. The softening point of the glass sealing material is more preferably 300°C or lower, and even more preferably 270°C or lower. Also, the other glass sealing material is preferably a glass material having a softening point lower than that of the glass sealing material by 50° C. or more.

As the glass sealing material and other glass sealing materials, for example, the glass materials described in Patent Document 4 (JP-A-2013-032255) and Patent Document 5 (WO 2017/126378) can be preferably used. As an example of the composition, when the components of the glass are represented by oxides, it consists of three or more kinds of oxides, contains V ₂ O ₅ and Ag ₂ O as main components, and TeO ₂ and/or or contains Li ₂ O, contains one or more of the group consisting of K ₂ O, MgO, P ₂ O ₅ , BaO, ZnO, and WO ₃ as a second optional component, and Al ₂ as a third optional component A low melting point lead-free glass material containing at _{least one} selected from the group consisting of O3 _{, Fe2O3 ,} Y2O3 _{, La2O3 , CeO2} , _{Er2O3 ,} and _Yb2O3 It can be preferably used.

As described in the above document, a glass material mixed with thermal expansion coefficient adjusting particles may be used to adjust the thermal expansion coefficient of the sealing material.

{Second embodiment}
[Vacuum insulation panel]
The vacuum insulation panel according to the second embodiment differs from the vacuum insulation panel according to the first embodiment in the configuration of the sealing portion reinforcing member, and is otherwise the same. Therefore, only the sealing portion reinforcing member will be described.

(sealing part reinforcing member)
FIG. 3A is a schematic cross-sectional view showing another example of the vicinity of the glass sealing portion in which the sealing portion reinforcing member is inserted. As shown in FIG. 3A, the sealing portion reinforcing member 61 of the vacuum insulation panel 101 according to the second embodiment is made of a metal material sheet folded in two and having a rectangular cross section (for example, a rectangular parallelepiped or a prism) made of a resin material or a ceramic material. It is a complex that sandwiches Although there is no particular limitation on the method/shape of folding in two, from the viewpoint of suppressing stress concentration leading to breakage, it is preferable to fold into a U-shaped cross section as shown in the figure. From the viewpoint of maintaining the degree of vacuum in the internal space 40 for a long period of time, it is preferable to arrange the bent portion (U-shaped portion) of the metal material sheet on the side facing the internal space 40 .

The metal material, resin material, and ceramic material used for the sealing portion reinforcing member 61 may be the same as those used in the first embodiment. The thickness of the metal material sheet is preferably 0.03 mm or more and 0.5 mm or less from the viewpoint of airtightness, bending workability, and manufacturing cost.

One main surface of the vacuum insulation panel faces the high temperature side, and the other main surface faces the low temperature side. A difference occurs in heat shrinkage. If the temperature difference between the high temperature side and the low temperature side is not so large, the difference in thermal expansion/contraction will not be a big problem, but if the temperature difference between the high temperature side/low temperature side is very large, the thermal expansion/contraction If the difference becomes large, there is a risk that the entire panel will warp or the glass seal will break.

On the other hand, the sealing portion reinforcing member 61 is thermally expanded/heated due to deformation of the U-shaped bent portion of the metal material sheet, elastic deformation of the sandwiched resin material, and interface slip between the sandwiched ceramic material and the metal material sheet. It has the advantage of absorbing contraction differences and reducing those risks.

In addition, by forming a composite of a metal material and a resin material or a ceramic material, it is possible to enjoy both the mechanical properties and airtightness advantages of the metal material and the low thermal conductivity advantage of the resin material or ceramic material. be able to.

{Third embodiment}
[Vacuum insulation panel]
The vacuum insulation panel according to the third embodiment differs from the vacuum insulation panel according to the second embodiment in the configuration of the sealing portion reinforcing member, and is otherwise the same. Therefore, only the sealing portion reinforcing member will be described.

(sealing part reinforcing member)
FIG. 3B is a schematic cross-sectional view showing still another example of the vicinity of the glass sealing portion in which the sealing portion reinforcing member is inserted. As in the second embodiment, the sealing portion reinforcing member 62 of the vacuum insulation panel 102 according to the third embodiment is made of a metal material sheet folded in two and having a circular cross section (for example, a sphere or a cylinder) made of a resin material or a ceramic material. It is a composite that sandwiches materials. Although there is no particular limitation on the method/shape of folding in two, from the viewpoint of suppressing stress concentration leading to breakage, it is preferable to fold into a U-shaped cross section as shown in the figure. From the viewpoint of maintaining the degree of vacuum in the internal space 40 for a long period of time, it is preferable to arrange the bent portion (U-shaped portion) of the metal material sheet on the side facing the internal space 40 .

The metal material, resin material, and ceramic material used for the sealing portion reinforcing member 62 can be the same as those in the first embodiment. The thickness of the metal material sheet is preferably 0.03 mm or more and 0.5 mm or less from the viewpoint of airtightness, bending workability, and manufacturing cost.

Since the sealing portion reinforcing member 62 is a composite sandwiching a resin material or a ceramic material having a circular cross section, it has the advantage of being able to absorb the difference in thermal expansion/thermal contraction more easily than in the case of the second embodiment. There is Furthermore, since the heat conduction path in the sealing portion reinforcing member 62 is narrower than in the case of the second embodiment, there is an advantage that lower heat conductivity can be ensured.

{Fourth embodiment}
[Manufacturing method of vacuum insulation panel]
FIG. 4 is a flowchart showing an example of a method for manufacturing a vacuum insulation panel according to the present invention. As shown in FIG. 4, the method for manufacturing a vacuum insulation panel according to the present invention generally includes a first insulation plate preparation step S1, a second insulation plate preparation step S2, a glass sealing portion formation step S3, and an exhaust port vacuum sealing step S4. The first heat insulating plate preparing step S1 includes a sealing portion reinforcing member inserting step S1a and a spacer dispersing step S1b. Further, the second heat insulating plate preparing step S2 may include a heat reflective film forming step S2a.

Next, each step of the manufacturing method will be described in more detail. First, each part necessary for manufacturing (a pair of metal plates constituting both surfaces of the vacuum insulation panel, a metal lid that closes the exhaust port, a glass sealing material (preferably frit or paste) used in the glass sealing part, a metal lid Another glass sealing material (preferably frit or paste), a sealing portion reinforcing member, a spacer, and an adhesive for the spacer) for sealing are prepared separately.

(First insulation plate preparation step S1)
Step S1 is a step of applying a glass sealing material to the peripheral edge region of one main surface of one of the pair of metal plates and pre-baking to prepare a first insulating plate. First, a glass sealing material is built up and applied to the peripheral region of one main surface of one of the pair of metal plates.

Next, as a sealing portion reinforcing member insertion elementary step S1a, a sealing portion reinforcing member is inserted in the build-up application portion of the glass sealing material. At this time, the sealing portion reinforcing member may be inserted so as to be inserted into the build-up application portion of the glass sealing material, or the sealing portion reinforcing member may be placed on the build-up application portion and then the sealing portion. A glass sealing material may be further applied on top of the reinforcing member.

Next, the temperature is raised to the softening point of the glass sealing material or higher, and the glass sealing material (including the sealing portion reinforcing member) is calcined on the peripheral edge region of the main surface of one of the metal plates.

Next, in the spacer distributing arrangement step S1b, after applying a spacer adhesive in the form of a planar lattice to the inner region (the region that will become the internal space) of the calcined glass sealing material, the spacers are rolled in the region. Glue while placing. The adhesive may be a glass sealing material used in the glass sealing portion, or may be an organic adhesive that is completely thermally decomposed in the subsequent heat treatment of the glass sealing portion forming step S3. There is no particular limitation on the method of applying the adhesive, and conventional methods can be used as appropriate.

(Second insulation plate preparation step S2)
Step S2 is a step of preparing a second heat insulating plate to face the first heat insulating plate. At this time, in the heat reflective film forming step S2a, a heat reflective film may be formed on the surface of the second heat insulating plate facing the first heat insulating plate. Although the heat ray reflective film forming step S2a is not an essential step, performing it contributes to lowering the heat conductivity of the vacuum heat insulating panel. Mirror surface processing may be performed instead of forming the heat ray reflective film.

(Glass sealing portion forming step S3)
In step S3, the first heat insulating plate and the second heat insulating plate are arranged facing each other so that the surface of the first heat insulating plate to which the glass sealing material is calcined faces the inside, and the softening point of the glass sealing material is -10°C. and the softening point plus 20° C. or less to seal the first heat insulating plate and the second heat insulating plate to form a glass sealing portion. When compressive stress is applied between the first heat insulating plate and the second heat insulating plate, the heat treatment temperature may range from the softening point of the glass sealing material -10°C to the softening point. If no compressive stress is applied between the plate and the second insulating plate, the heat treatment temperature is preferably in the range from the softening point to the softening point +20°C.

Here, by measuring the electrical resistivity between the sealed first and second heat insulating plates, it is possible to determine to some extent whether or not the glass sealing portion is properly formed. This is because electrical resistance and thermal resistance qualitatively show the same tendency. If the measured electrical resistivity is 100 kΩ·m or more, it can be determined that the glass sealing portion has sufficient thermal resistance. On the other hand, if the electrical resistivity is less than 100 kΩ·m, it means that an electrical short circuit/thermal short circuit has occurred somewhere between the first and second heat insulating plates, so the product is rejected. can be determined.

(Exhaust port vacuum sealing step S4)
In step S4, while evacuating the internal space from the exhaust port, the temperature is raised to a temperature higher than the softening point of the other glass sealing material and lower than the softening point + 20 ° C., and the metal lid and the other glass sealing material are separated. is used to vacuum-seal the exhaust port. The degree of vacuum in the internal space is preferably less than 1×10 ⁻¹ Pa, more preferably 5×10 ⁻² Pa or less. By using another glass sealing material having a softening point lower than that of the glass sealing material used in the glass sealing portion, the exhaust port can be vacuum-sealed without causing adverse thermal effects on the glass sealing portion.

Here, vacuum sealing using a metal lid and other glass sealing material has been described, but the essence of the present invention is not limited to this, and the internal space is vacuum sealed at a desired degree of vacuum. If possible, vacuum sealing may be performed by other methods.

Hereinafter, the present invention will be described more specifically based on some experimental examples. However, the present invention is not limited to the experimental examples taken up here, and includes variations thereof.

[Experiment 1]
(Preparation of each part)
A pair of stainless steel plates (SUS 304, 1000 mm long x 800 mm wide x 0.5 mm thick) were prepared as a pair of metal plates that make up both surfaces of the vacuum insulation panel, and a stainless steel plate (SUS 304, 10 mm diameter×0.5 mm thickness), a quartz glass plate (6 mm width×0.5 mm thickness) was prepared as a sealing portion reinforcing member, and quartz glass beads (0.7 mm diameter) were prepared as spacers.

As the glass sealing material used in the glass sealing part, glass powder (STA-1 to STA-5, each average A lead-free glass paste was prepared by mixing thermal expansion coefficient adjusting particles (zirconium phosphate tungstate), a binder (isobornylcyclohexanol) and a solvent (α-terpineol). As the spacer adhesive, the same lead-free glass paste as the glass sealing material used in the glass sealing portion was used.

Similarly, as another glass sealing material for sealing metal lids, glass powder having the nominal composition shown in Table 1 (STA-6, average A lead-free glass paste was prepared by mixing thermal expansion coefficient adjusting particles (zirconium phosphate tungstate), a binder (isobornylcyclohexanol) and a solvent (α-terpineol).

(Investigation of properties of glass powder)
The softening point Ts of each of the glass powders STA-1 to STA-6 obtained above was investigated by differential thermal analysis (DTA) according to the methods and definitions described in Patent Documents 4 and 5. The results are shown in Table 1 together with the nominal composition.

[Experiment 2]
(Preparation of vacuum insulation panel)
According to the flow shown in FIG. 4, 10 vacuum insulation panels were produced using each component prepared in Experiment 1. As shown in FIG. In producing the vacuum heat insulating panel, first, each part (metal plate, metal lid, sealing portion reinforcing member, spacer) was cleaned with ozone to remove contaminants such as organic substances.

In the first heat insulating plate preparing step S1, the sealing portion reinforcing member insertion step S1a includes placing the sealing portion reinforcing member on the build-up application portion of the glass sealing material, and then placing the sealing portion reinforcing member on the sealing portion reinforcing member. Then, the glass sealing material was further applied as build-up. The temporary baking temperature of the glass sealing material was the softening point of the glass powder used. The arrangement form of the spacers in the spacer distributing arrangement step S1b was a square lattice (see FIG. 1).

In the second heat insulating plate preparing step S2, the heat reflective film forming step S2a was performed.

In the glass sealing portion forming step S3, a hot air circulating heating furnace is used to heat to the softening point temperature of the glass powder used to seal the first insulating plate and the second insulating plate, and the glass sealing portion is formed. formed (the height of the inner space is about 0.7 mm). After the glass sealing portion forming step S3, the electric resistivity between the first heat insulating plate and the second heat insulating plate was measured for each sample. As a result, all the samples showed an electrical resistivity of 100 kΩ·m or more, confirming that they were sound samples.

In the exhaust port vacuum sealing step S4, a vacuum suction cap with a metal lid preliminarily applied and pre-baked with a paste containing glass powder STA-6 is formed on the first or second heat insulating plate. The entire heat insulating panel was heated to the softening point of the glass powder STA-6 and held while the internal space was being evacuated. When the degree of vacuum in the internal space reached 5×10 ⁻² Pa, the exhaust port was covered with a metal lid, and then the whole was cooled to produce a vacuum insulation panel according to the present invention.

[Experiment 3]
(Inspection and testing of vacuum insulation panels)
All the vacuum insulation panels obtained in Experiment 2 were visually inspected. As a result, damage such as cracks was not observed in the glass sealing portion, and there was no problem in appearance. In addition, 2 samples were extracted from each of 10 samples, and a helium leak test was performed. As a result, it was confirmed that the glass sealing portion and the metal lid were vacuum-sealed.

Three samples were extracted from each of ten samples, and a water immersion test (hot water at 50°C for 30 days) was performed. As a result, it was confirmed that the internal space was maintained in a vacuum state without hot water entering into the internal space in all the test samples. In addition, three samples were further extracted from each sample, and a temperature cycle test (+50°C ⇔ -20°C, 1000 cycles) was performed. As a result, it was confirmed that the internal space was maintained in a vacuum state. From these results, it was confirmed that the glass sealing portion and the metal lid of the vacuum insulation panel according to the present invention have high reliability in terms of vacuum sealing.

Next, the remaining two sheets of each sample were subjected to an accelerated thermal conductivity deterioration test (maintained in a constant temperature bath at a temperature of 85° C. and a relative humidity of 85%). The thermal conductivity of the test sample was measured using the JIS standard protected hot plate method (GHP method). At this time, a conventional vacuum insulation panel (commercially available) filled with glass wool was separately prepared, and an accelerated thermal conductivity deterioration test was conducted together.

FIG. 5 is a graph showing the relationship between elapsed time and thermal conductivity in an accelerated test of the vacuum insulation panel of the present invention using glass powder STA-1 and the conventional vacuum insulation panel filled with glass wool. Plots in the graph are averages of two samples.

As shown in Fig. 5, the conventional vacuum insulation panel has an initial thermal conductivity of about 2 mW/(m K) and a thermal conductivity of about 8 mW/(m K) after 10 years. , and it can be seen that there is a large deterioration. In contrast, the vacuum insulation panel of the present invention has an initial thermal conductivity of about 0.2 mW/(m K) and a thermal conductivity of about 0.5 mW/(m K) after 10 years. Therefore, it is confirmed that both extremely excellent low thermal conductivity and extremely excellent durability are achieved.

It has been separately confirmed that the same results as in FIG. 5 are obtained also in the vacuum insulation panel of the present invention using other glass powders.

From the various experiments described above, it was demonstrated that the present invention can provide a vacuum insulation panel with lower thermal conductivity and higher durability than conventional ones, and a method for manufacturing the same. By using the vacuum insulation panel according to the present invention, the thickness of the heat insulator can be reduced without deteriorating the heat transmission coefficient/heat transmittance of the heat insulator. In addition, since the vacuum insulation panel according to the present invention does not use heat insulation materials with high recycling costs (for example, glass fiber, ceramic fiber, plastic foam, etc.), it is considered that the recyclability is higher than before.

The above-described embodiments and experimental examples are described to aid understanding of the present invention, and the present invention is not limited only to the specific configurations described. For example, it is possible to replace part of the configuration of the embodiment with a configuration of common technical knowledge of a person skilled in the art, and it is also possible to add a configuration of common general technical knowledge of a person skilled in the art to the configuration of the embodiment. That is, in the present invention, part of the configurations of the embodiments and experimental examples of the present specification can be deleted, replaced with other configurations, or added with other configurations without departing from the technical idea of the invention. It is possible.

100, 101, 102...vacuum insulation panels,
10, 20...Metal plate, 30...Glass sealing portion, 40...Internal space, 50...Spacer,
60, 61, 62...sealing portion reinforcing member, 70...exhaust port, 80...metal lid.

Claims (15)

A vacuum insulation panel,
An internal space is formed by a pair of metal plates whose main surfaces face each other with a predetermined gap, and a glass sealing portion obtained by sealing the peripheral edge region of the pair of metal plates with a glass sealing material. The space is in a high vacuum state,
In the internal space, spacers for maintaining the predetermined spacing are distributed in the form of a planar lattice,
A sealing portion reinforcing member for reinforcing the glass sealing portion is inserted through the glass sealing material in the glass sealing portion,
A vacuum insulation panel characterized by: The vacuum insulation panel of claim 1,
The glass sealing material is a lead-free glass material having a softening point of 330° C. or less,
The spacer is a sphere or column made of a ceramic material or a resin material,
The vacuum insulation panel, wherein the sealing portion reinforcing member is made of a metal material, a ceramic material, a metal material/resin material composite, or a metal material/ceramic material composite. In the vacuum insulation panel according to claim 1 or claim 2,
The glass sealing material is composed of three or more kinds of oxides when the components are expressed as oxides,
Containing V ₂ O ₅ and Ag ₂ O as main components,
containing TeO ₂ and/or Li ₂ O as a first optional component,
containing at least _one selected from the group consisting of _K2O , MgO, P2O5, BaO _, ZnO, and WO3 as a _second optional component,
containing one or more selected from the group consisting of Al ₂ O ₃ , Fe ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , CeO ₂ , Er ₂ O ₃ and Yb ₂ O ₃ as a third optional component; A vacuum insulation panel characterized by: In the vacuum insulation panel according to any one of claims 1 to 3,
A vacuum insulation panel, wherein the predetermined interval is 0.2 mm or more and 18 mm or less. In the vacuum insulation panel according to any one of claims 1 to 4,
A vacuum insulation panel, wherein the thickness of the glass sealing material interposed between the sealing portion reinforcing member and the metal plate in the glass sealing portion is 0.01 mm or more and less than 0.2 mm. In the vacuum insulation panel according to any one of claims 1 to 5,
A vacuum insulation panel, wherein the degree of vacuum of the internal space is less than 1×10 ⁻¹ Pa. In the vacuum insulation panel according to any one of claims 1 to 6,
A vacuum insulation panel, wherein the plane lattice includes one or more members selected from the group consisting of a square lattice, a rectangular lattice, a regular triangular lattice, an orthorhombic lattice and a parallel lattice. In the vacuum insulation panel according to any one of claims 1 to 7,
A vacuum insulation panel, wherein the metal plate has a thickness of 0.1 mm or more and 1 mm or less. In the vacuum insulation panel according to any one of claims 1 to 8,
A vacuum insulation panel, wherein the electric resistivity between the pair of metal plates is 100 kΩ·m or more. In the vacuum insulation panel according to any one of claims 1 to 9,
A vacuum insulation panel, wherein the vacuum insulation panel has a thermal conductivity of less than 2 mW/(m·K) at room temperature. In the vacuum insulation panel according to any one of claims 1 to 10,
At least one of the pair of metal plates is formed with an exhaust port for evacuating the internal space,
A vacuum insulation panel, wherein the exhaust port is sealed with a metal lid that closes the exhaust port and another glass sealing material. A vacuum insulation panel according to claim 11, wherein
The other glass sealing material is a lead-free glass material whose softening point is lower than the softening point of the glass sealing material by 50°C or more, and is composed of three or more kinds of oxides when the components are expressed as oxides. ,
Containing V ₂ O ₅ and Ag ₂ O as main components,
containing TeO ₂ and/or Li ₂ O as a first optional component,
containing at least _one selected from the group consisting of _K2O , MgO, P2O5, BaO _, ZnO, and WO3 as a _second optional component,
containing one or more selected from the group consisting of Al ₂ O ₃ , Fe ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , CeO ₂ , Er ₂ O ₃ and Yb ₂ O ₃ as a third optional component; A vacuum insulation panel characterized by: A method for manufacturing a vacuum insulation panel according to any one of claims 1 to 10,
a first insulating plate preparing step of preparing a first insulating plate by building up and applying the glass sealing material to the peripheral edge region of one main surface of one of the pair of metal plates and pre-baking it;
a second heat insulating plate preparing step of preparing a second heat insulating plate to face the first heat insulating plate;
The first heat insulating plate and the second heat insulating plate are arranged facing each other so that the surface of the first heat insulating plate to which the glass sealing material is calcined faces the inside, and the softening point of the glass sealing material is -10°C. and a step of forming the glass sealing portion by raising the temperature to a temperature equal to or higher than the softening point +20° C. and sealing the first insulating plate and the second insulating plate to form the glass sealing portion. have
The step of preparing the first insulating plate includes:
a sealing portion reinforcing member inserting step of inserting the sealing portion reinforcing member in the build-up application portion after the build-up application of the glass sealing material;
a spacer dispersing and arranging step of applying the adhesive in the form of the planar lattice to the region corresponding to the internal space and then adhering and arranging the spacers while rolling the spacers;
A method for manufacturing a vacuum insulation panel, characterized by: A method for manufacturing a vacuum insulation panel according to claim 11 or 12,
a first insulating plate preparing step of preparing a first insulating plate by building up and applying the glass sealing material to the peripheral edge region of one main surface of one of the pair of metal plates and pre-baking it;
a second heat insulating plate preparing step of preparing a second heat insulating plate to face the first heat insulating plate;
The first heat insulating plate and the second heat insulating plate are arranged facing each other so that the surface of the first heat insulating plate to which the glass sealing material is calcined faces the inside, and the softening point of the glass sealing material is -10°C. a glass sealing portion forming step of forming the glass sealing portion by increasing the temperature to a temperature of the softening point +20 ° C. or less and sealing the first insulating plate and the second insulating plate to form the glass sealing portion;
While evacuating the internal space from the exhaust port, the temperature is raised to a temperature equal to or higher than the softening point of the other glass sealing material and equal to or lower than the softening point +20°C of the other glass sealing material, so that the metal lid and the other glass sealing material are separated. and an exhaust port vacuum sealing step of vacuum sealing the exhaust port using
The step of preparing the first insulating plate includes:
a sealing portion reinforcing member inserting step of inserting the sealing portion reinforcing member in the build-up application portion after the build-up application of the glass sealing material;
a spacer dispersing and arranging step of applying the adhesive in the form of the planar lattice to the region corresponding to the internal space and then adhering and arranging the spacers while rolling the spacers;
A method for manufacturing a vacuum insulation panel, characterized by: In the method for manufacturing a vacuum insulation panel according to claim 13 or 14,
The step of preparing the second heat insulating plate includes a heat reflecting film forming step of forming a heat reflecting film on a surface of the second heat insulating plate facing the first heat insulating plate. Production method.

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