Resin member and vacuum heat insulating material

Abstract

A problem addressed by the present invention is to provide a vacuum heat insulating material having a good surface smoothness level as a vacuum heat insulating material, excellent strength in the thickness direction, and good workability, and to provide a core material of the vacuum heat insulating material. Provided is an approximately flat resin member, wherein the density of the resin member is from 50 kg / m3 to 250 kg / m3 and Dh0 is less than 7.5 mm when the amount of denting (mm) of the resin member when a load is applied to the resin member by cylindrical stainless steel SUS304 having a diameter of 6 mm and a mass of 3 kg in a direction parallel to the thickness direction of the resin member is taken to be Dh0.

Description

Resin components and vacuum insulation materials

[0001] The present invention relates to a resin member and a vacuum heat insulating material.

[0002] In recent years, concerns about global warming have made the reduction of greenhouse gas emissions an urgent priority. One of the key measures for reducing greenhouse gas emissions through energy conservation is the high insulation of buildings and other structures, i.e., thermal insulation. While foamed plastic insulation materials with high thermal insulation performance are mainstream, the use of vacuum insulation materials is also increasing due to the need for further improvements in thermal insulation performance and environmental concerns. While it is known that fibrous materials, powders, and foams can be used as the core material for vacuum insulation materials, the most commonly used fibrous materials and even powders often lack the surface smoothness required for vacuum insulation materials. Even vacuum insulation materials with foam cores have issues with surface smoothness both immediately after production and over time. Furthermore, particularly when using fibrous core materials, the thickness (thickness change) is large under atmospheric pressure compared to the thickness under reduced pressure, resulting in poor workability during the process of filling airtight bags to produce vacuum insulation materials. On the other hand, in the case of vacuum insulation panels with foam cores, there is a known technology that uses so-called open-cell foam cores that maintain the cell structure, but the strength in the thickness direction is barely enough to withstand reduced pressure (atmospheric pressure). Therefore, there is a concern that the cells will be destroyed if a load is applied in the thickness direction during handling, such as during on-site installation, which will further deteriorate the surface smoothness.

[0003] Patent Document 1 discloses a technology relating to a vacuum insulation material in which a core material made of a phenolic resin cured foam contains bubbles of 50 to 500 μm, and fine holes of 0.5 to 30 μm are formed on the outer periphery of the bubbles, so that the porosity of the phenolic resin cured foam is 50% or more, thereby improving structural strength and reducing the overall weight.

[0004] Furthermore, Patent Document 2 discloses a vacuum insulation material that uses a lightweight, high-performance, non-fluorocarbon insulating material with a further reduced thermal conductivity by using, as the core material, an open-cell foam that is formed by compressing it after foaming to flatten the cells, and reducing the pressure to 0.1 to 0.01 Torr.

[0005] Furthermore, Patent Document 3 discloses a technology that prevents deformation of the open-cell urethane due to atmospheric compression after evacuation throughout the entire insulator by not providing a deformed bubble membrane at the apex or ridge of the core material that constitutes the vacuum insulator, while also maintaining the vacuum level and insulating performance of the vacuum insulator for a long period of time.

[0006] Special table publication No. 2014-503054 Publication of Japanese Patent Application Publication No. Hei 6-213561 Publication of Japanese Patent Application Publication No. 2020-020431

[0007] However, in Patent Document 1, the open-cell phenolic foam is used as the core material of the vacuum insulation material while preserving its cell structure, so the cell structure of the phenolic foam as the core material is merely maintained in an apparent reduced-pressure state, and there are areas where the cells are locally destroyed because they cannot withstand reduced pressure (atmospheric pressure), resulting in poor surface smoothness immediately after production, and further problems such as the surface smoothness not being stabilized as the cells are destroyed over time.Furthermore, since the cell structure is maintained, the strength in the thickness direction is just enough to withstand reduced pressure (atmospheric pressure), so when an impact such as a load equal to or greater than atmospheric pressure is applied in the thickness direction, the cells are easily destroyed, resulting in further problems with poor surface smoothness.

[0008] Patent Document 2 discloses a technology related to a vacuum insulation material using an open-cell compressed rigid urethane foam as a core material. The technology is characterized by maintaining the interconnected cells in the foam in a flattened state in order to increase the degree of vacuum to 0.1 to 0.01 Torr. However, similar to Patent Document 1, the technology suffers from the following problems: immediately after production and over time, the cells are unable to withstand atmospheric pressure and are locally destroyed, resulting in poor surface smoothness; and the surface smoothness does not stabilize over time due to the restoring force of the deformed cells. Furthermore, as in Patent Document 1, the technology maintains a cellular structure, so that the strength in the thickness direction can barely withstand reduced pressure (atmospheric pressure). However, when an impact such as a load exceeding atmospheric pressure is applied in the thickness direction during handling, such as during on-site construction, the cells are easily destroyed, further reducing the surface smoothness.

[0009] Furthermore, Patent Document 3 discloses a technology for increasing the compressive strength of open-cell urethane foam, characterized by not providing deformed cell membranes at the apexes or ridges of the core material that constitutes the vacuum insulator. While this makes it possible to suppress deformation due to atmospheric compression after evacuation to a certain extent across the entire insulator, the compressive strength is not high, and when an impact such as a load is applied in the thickness direction, the cells are easily destroyed, resulting in poor surface smoothness.

[0010] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a vacuum insulation material and its core material that have a good level of surface smoothness as a vacuum insulation material, excellent strength in the thickness direction, and good workability.

[0011] The inventors of the present invention have conducted extensive research to solve the above problems and have developed a vacuum insulation material with excellent surface smoothness by compressing a foam to destroy the cellular structure and producing a resin member that is substantially bubble-free. This resin member is then inserted into an outer film bag as a core material and the inside of the bag is then subjected to reduced pressure. Furthermore, this vacuum insulation material has excellent load resistance in the thickness direction, so that a good level of surface smoothness is maintained. The present invention is as follows.

[0012] [1] A substantially flat resin member, wherein the density of the resin member is 50 kg / m ３More than 250kg / m ３ [2] The resin member according to [1], wherein, when a load is applied to the resin member from a cylindrical stainless steel SUS304 having a diameter of 6 mm and a mass of 3 kg in a direction parallel to the thickness direction of the resin member, Dh0 is defined as the amount of depression (mm) of the resin member, and Dh0 is less than 7.5 mm. [3] The resin member according to [1], wherein, in a photograph of a 0.25 mm x 0.25 mm field of view taken with an electron microscope at 500x magnification, with the center position of the thickness direction of the resin member at the center of the field of view and the vertical direction of the field of view aligned with the thickness direction of the resin member, there are zero or one connected resin skeletons surrounding the bubble film. [3] The resin member according to [1] or [2], wherein the resin member is one or more resins selected from the group consisting of phenolic resins, urethane resins, and styrene resins. [4] The resin member according to any one of [1] to [3], wherein the resin member is a phenolic resin. [5] A vacuum heat insulating material comprising: a sealed bag; and the resin member according to any one of [1] to [4], which is sealed in the bag under reduced pressure. [6] The density of the vacuum heat insulating material is 60 kg / m ３ More than 260kg / m ３ [7] The vacuum insulation material according to [5], wherein the thermal conductivity of the vacuum insulation material in an environment of 23°C is 0.010 W / (m K) or less. [8] The vacuum insulation material according to any of [5] to [7], wherein the surface smoothness level of the vacuum insulation material is 1.8 mm or less. [9] The vacuum insulation material according to any of [5] to [8], wherein, when a load is applied to the vacuum insulation material from a cylindrical stainless steel SUS304 having a diameter of 6 mm and a mass of 5 kg in a direction parallel to the thickness direction of the resin member, Dh1 is defined as a depression amount (mm) of the vacuum insulation material, and Dh1 is less than 7.5 mm.

[0013] According to the present invention, it is possible to provide a vacuum heat insulating material having a good level of surface smoothness and excellent strength in the thickness direction, and a core material thereof.

[0014] FIG. 1 is a perspective view schematically showing a resin member of Example 1. FIG. 2 is a perspective view schematically showing a vacuum insulation material of Example 1. FIG. 3 is a plan view schematically showing the vacuum insulation material of Example 1. FIG. 4 is a side view schematically showing a cross section of the vacuum insulation material of Example 1. FIG. 5 is a plan view schematically showing a vacuum insulation material of Example 4. FIG. 6 is a photograph of a 0.25 mm x 0.25 mm field of view taken with an electron microscope at 500x magnification, so that the center position in the thickness direction of the resin member raw material (resin foam before the bubbles are destroyed) of Example 1 is located in the center of the field of view, and the vertical direction of the field of view is aligned with the thickness direction of the resin member. FIG. 7 is a photograph of a 0.25 mm x 0.25 mm field of view taken with an electron microscope at 500x magnification, so that the center position in the thickness direction of the resin member of Example 1 is located in the center of the field of view, and the vertical direction of the field of view is aligned with the thickness direction of the resin member. Fig. 8 is a photograph of a 0.25 mm x 0.25 mm field of view taken with an electron microscope at 500x magnification, with the center position in the thickness direction of the resin member of Comparative Example 1 in the center of the field of view and the vertical direction of the field of view aligned with the thickness direction of the resin member. Fig. 9 is a photograph showing the connected resin skeleton surrounding the bubble film in the photograph of Fig. 8. Fig. 10 is a schematic diagram of an example of a measuring device for Dh0.

[0015] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. Note that the present invention is not limited to the following embodiment, and various modifications can be made within the scope of the gist of the present invention.

[0016] The density, closed cell content, dent amount of the resin member of this embodiment when a load is applied to the resin member from cylindrical stainless steel SUS304 having a diameter of 6 mm and a mass of 3 kg in a direction parallel to the thickness direction of the resin member, the presence or absence of a substantial bubble structure at the center position in the thickness direction of the resin member (i.e., the number of connected resin skeletons surrounding the bubble film in a photograph of a 0.25 mm × 0.25 mm field of view taken at 500 times magnification with an electron microscope), and further, the thermal conductivity, density, surface smoothness level, and dent amount of the vacuum insulation material of this embodiment in an environment of 23°C when a load is applied to the vacuum insulation material from cylindrical stainless steel SUS304 having a diameter of 6 mm and a mass of 5 kg in a direction parallel to the thickness direction of the resin member are determined by the method described in the examples.

[0017] (Resin member) The resin member of this embodiment is a substantially flat plate-shaped resin member, and the density of the resin member is 50 kg / m ３ More than 250kg / m ３ When a load is applied to the resin member from a cylindrical stainless steel SUS304 having a diameter of 6 mm and a mass of 3 kg in a direction parallel to the thickness direction of the resin member, the amount of depression (mm) of the resin member is defined as Dh0, and Dh0 is less than 7.5 mm.

[0018] 4 is a side view showing a schematic cross section of a vacuum heat insulating material according to Example 1, which will be described later. In this example, the vacuum heat insulating material 3 is obtained by covering a resin member 1 with a highly airtight bag-like film 4, then evacuating the air, and airtightly sealing and sealing the bag-like film with a heat-sealed portion 5.

[0019] In this embodiment, the term "resin member" refers to a solid object made of resin. The resin member may be a homogeneous resin, or may contain gases such as air uniformly or non-uniformly, and may or may not have a surface material attached. It may also contain a binder, a coating agent, or the like, and the processing form of these may not be important. Furthermore, the resin member may contain additives other than the main component of the resin member. The raw materials used to manufacture the resin member are referred to as resin member raw materials.

[0020] The resin member has a substantially flat plate shape. Examples of substantially flat plate shapes include a rectangular parallelepiped, a prism, and a disk. In this embodiment, the term "substantially rectangular parallelepiped" refers to a rectangular parallelepiped whose surfaces are not necessarily flat, and includes curved surfaces, surfaces connected by curved surfaces, and corners that are also curved.

[0021] The density of the resin member in this embodiment is 50 kg / m ３ More than 250kg / m ３ and preferably 80 kg / m ３ More than 170kg / m ３ or less, more preferably 90 kg / m ３ More than 160kg / m ３ More preferably, 100 kg / m or less ３ More than 150kg / m ３ Below 110 kg / m, most preferably ３ More than 140kg / m ３ The density of the resin member is 50 kg / m or less. ３ If the density of the resin member is 250 kg / m or more, the resin member is less likely to dent when a load is applied in a direction perpendicular to the thickness direction, so that when this member is used as the core material of a vacuum insulation material, the surface smoothness level of the vacuum insulation material is good, and the mechanical strength such as load resistance as a vacuum insulation material can be ensured, and dents and breakage can be avoided. ３ When this material is used as the core material of a vacuum insulation material, the weight of the vacuum insulation material does not increase and handling is excellent. Furthermore, the thermal conductivity of the vacuum insulation material also depends on the density of the resin member, and there is an optimum range.

[0022] The resin member in this embodiment is characterized by a small dent (mm) when a load is applied parallel to its thickness direction by a cylindrical SUS304 stainless steel member with a diameter of 6 mm and a mass of 3 kg. That is, when the dent is Dh0, if Dh0 is less than 7.5 mm, the vacuum insulation panel using the resin member as the core material is less likely to deform and experience performance degradation even when subjected to an impact in the thickness direction during handling, such as on-site installation. Dh0 is preferably less than 6 mm, more preferably less than 4 mm, even more preferably less than 2.5 mm, and most preferably less than 1.5 mm. Dh0 is, for example, 0 mm or greater. The thickness direction is the direction of the shortest distance between two opposing surfaces of a substantially flat resin member. If a cylindrical object penetrates the resin member in this evaluation, multiple resin members are stacked and re-evaluated to determine Dh0.

[0023] 10 is a schematic diagram of an example of a Dh0 measurement device. A resin member 9 is placed on two pieces of wood 14 arranged parallel to each other with a 20 mm gap between them, so that the overlap between the resin member 9 and each piece of wood 14 is 5 mm or more. A cylindrical stainless steel SUS304 piece (reference numeral 10) with a diameter of 6 mm and a mass of 3 kg is suspended above the resin members by a wire 11 that can be moved up and down by rotating a position adjustment handle 13 using a pulley 12.

[0024] Stainless steel SUS304 corresponds to ISO standard X5CrNi18-10 (4301-304-00-I).

[0025] When a fiber is used as the core material, the thickness (thickness change) under atmospheric pressure is large compared to the thickness under reduced pressure, which results in poor workability when filling an airtight bag with the fiber core material to produce a vacuum insulation material. More specifically, for example, (1) the work of inserting a fiber core material that has a large thickness under atmospheric pressure into a bag with a small thickness (gusset) is cumbersome, and (2) when inserting the fiber core material into the bag and decompressing it, unevenness is likely to occur on the surface of the bag or the bag may bend, resulting in poor workability. For these reasons, it is generally more desirable to use a material made of resin foam (resin component raw material) as the core material of a vacuum insulation material than a fiber, which generally has a large thickness difference between the core material and the vacuum insulation material.

[0026] Furthermore, it has been found that in the resin member of this embodiment, in a photograph of a 0.25 mm x 0.25 mm field of view taken at 500x magnification using an electron microscope, with the center position of the thickness direction of the resin member (half the thickness position) in the center of the field of view and the vertical direction of the field of view aligned with the thickness direction of the resin member, it is preferable that the number of connected resin skeletons surrounding the bubble membrane is 0 or 1 (also referred to as "having substantially no bubble structure").

[0027] The field of view refers to a 0.25 mm × 0.25 mm area photographed at 500x magnification using an electron microscope. The area at the bottom of the photograph in Figure 7, etc., where information such as the magnification and scale bar is written, is not included in the field of view because it is not the photographed area.

[0028] Figure 8 is a photograph of a 0.25 mm x 0.25 mm field of view taken with an electron microscope at 500x magnification, with the center of the field of view of the resin member of Comparative Example 1 in the thickness direction and the vertical direction of the field of view aligned with the thickness direction of the resin member. In the photograph of Figure 8, a bubble film 7 surrounded by a bubble skeleton 6 can be observed. The bubble skeleton 6 is the resin skeleton that forms the foam, and the bubble film 7 refers to the resin film surrounded by the resin skeleton.

[0029] Figure 9 is a photograph showing the connected resin skeletons surrounding the bubble membranes in the photograph of Figure 8 to evaluate the presence or absence of a substantial bubble structure. A and B surrounded by black lines indicate the connected resin skeletons surrounding the bubble membranes. Therefore, in the photographs of Figures 8 and 9, the number of connected resin skeletons surrounding the bubble membranes is two (A and B).

[0030] 7 is a photograph of a 0.25 mm × 0.25 mm field of view taken at 500x magnification with an electron microscope, with the center of the field of view being the center of the thickness direction of the resin member of Example 1 and the vertical direction of the field of view being the thickness direction of the resin member. In this photograph, the number of connected resin skeletons surrounding the bubble film is zero.

[0031] If there is essentially no bubble structure at the center position in the thickness direction, when this material is used as the core material of a vacuum insulation material, the vacuum insulation material is likely to have sufficient strength, have a good level of surface smoothness, and is less likely to dent when a load is applied in a direction perpendicular to the thickness direction, which is preferable.

[0032] Although there is no restriction on whether or not there is a bubble structure in areas other than the central position in the thickness direction, it is more preferable that there is essentially no bubble structure, as in the central position in the thickness direction, because this makes it easier to achieve improved surface smoothness and improved strength in the thickness direction, and the thermal conductivity of vacuum insulation material using this as the core material is likely to decrease.

[0033] The size of the resin member can also be appropriately set depending on the purpose. In the case of a substantially rectangular parallelepiped shape, the length of one side excluding the thickness direction is preferably 30 mm to 6000 mm, more preferably 50 mm to 3000 mm, even more preferably 100 mm to 2000 mm, and most preferably 200 mm to 1200 mm. The thickness of the resin member is preferably 1 mm to 120 mm, more preferably 2 mm to 80 mm, even more preferably 3 mm to 50 mm, and most preferably 5 mm to 50 mm.

[0034] The closed cell ratio of the resin member of this embodiment is not particularly limited and is, for example, 10% or less, preferably 5% or less, more preferably 1% or less, even more preferably 0.5% or less, and most preferably 0%. When the closed cell ratio of the resin member is 5% or less, Dh0 can be reduced, and in the case of a resin foam, the amount of gas enclosed in the bubbles is reduced, so the thermal conductivity of the enclosed gas can be suppressed without being utilized, and therefore the thermal conductivity of the vacuum insulation material can be reduced when this is used as the core material of the vacuum insulation material.

[0035] The material of the resin member of this embodiment is not particularly limited, and examples thereof include phenolic resin; polystyrene; polyolefins such as polyethylene or polypropylene; polyacrylate; vinyl chloride; polyurethane; and the like. Alternatively, the resin member may be obtained by compressing a foam. Phenolic resin foam, rigid urethane resin foam, and polystyrene resin foam, which are prone to breakage of the cell structure due to excessive compression, are particularly preferred, with phenolic resin foam, which is a highly brittle material, being even more preferred. Compressing these resin foams preferably substantially eliminates the cell structure at the center in the thickness direction. For resin members with a surface material such as phenolic resin, the surface material may remain attached or the surface material may be peeled off.

[0036] In one embodiment, the resin component is one or more selected from the group consisting of a phenolic resin, a urethane resin, and a styrene resin, hi another embodiment, the resin component is a phenolic resin.

[0037] In one embodiment of the resin member, the thickness of the resin member under reduced pressure (130 Pa) is 50 to 100% of the thickness under atmospheric pressure.

[0038] In this embodiment, one or more remnants (offcuts) of resin foam can be used as the resin member raw material. Remnants of the same thickness can be arranged perpendicular to the thickness direction or stacked in the thickness direction, and the combination of multiple remnants is not limited. In this case, the resin member also uses one or more remnants of resin foam. Even if these are used as the core material of a vacuum insulation material, the pressure inside the airtight bag-like film covering the resin member is reduced, which increases the adhesion between the resin members, making it possible to integrate them and produce an excellent vacuum insulation material.

[0039] The resin member of this embodiment can be manufactured mainly as follows. A resin foam of the desired size is prepared, and the bubbles are destroyed by applying uniform pressure to the entire area of ​​the upper and lower surface layers in the thickness direction. When a resin foam is used as the raw material, the thickness is reduced (volume reduced) while simultaneously applying pressure (compression) and dissipating the foaming agent contained therein. This preferably results in a resin member that has substantially no cellular structure at the center position in the thickness direction. Here, a roller press or the like can be used as a method for applying uniform pressure to the entire area of ​​the upper and lower surface layers in the thickness direction, but is not particularly limited thereto. The value obtained by dividing the thickness of the resulting resin member by the thickness of the resin member raw material is defined as the volume reduction ratio.

[0040] FIG. 6 is a photograph of a field of view of 0.25 mm × 0.25 mm taken with an electron microscope at 500x magnification so that the center position in the thickness direction of the resin member raw material (a resin foam before the bubbles are destroyed) of Example 1 described below is located in the center of the field of view, and so that the up-down direction of the field of view is the thickness direction of the resin member.

[0041] The resin member of this embodiment can be covered with a highly airtight bag-like film, then evacuated, and the bag-like film can be airtightly joined and sealed to form a vacuum heat insulating material.

[0042] (Vacuum Insulation Material) The vacuum insulation material of the present embodiment is a vacuum insulation material including: a sealed bag; and any one of the resin members described above that is sealed in the bag under reduced pressure.

[0043] The resin member placed inside the bag of the vacuum heat insulating material is the resin member described above, and a description thereof will be omitted.

[0044] The thermal conductivity of the vacuum insulation material of this embodiment in an environment of 23°C is preferably 0.010 W / (m·K) or less. It is preferably 0.009 W / (m·K) or less, more preferably 0.008 W / (m·K) or less, even more preferably 0.007 W / (m·K) or less, and most preferably 0.006 W / (m·K) or less. If the thermal conductivity of the vacuum insulation material in an environment of 23°C is 0.01 W / (m·K) or less, it can exhibit high thermal insulation performance even when it is thin.

[0045] The density of the vacuum insulation material of this embodiment is, for example, 60 kg / m ３ More than 260kg / m ３ and preferably 70 kg / m ３ More than 200kg / m ３ or less, more preferably 85 kg / m ３ More than 175kg / m ３ More preferably, 110 kg / m or less ３ More than 170kg / m ３ Below 125 kg / m, most preferably ３ More than 155kg / m ３ The density of the vacuum insulation material is 60 kg / m or less. ３ If the density of the vacuum insulation material is 260 kg / m or more, mechanical strength such as load strength can be ensured, and breakage can be avoided. ３ If the thickness is less than this, the weight of the vacuum insulation material will not increase and handling will be excellent. The thermal conductivity of the vacuum insulation material also depends on the density of the resin member, and there is an optimum range.

[0046] The surface smoothness level of the vacuum insulation material of this embodiment is, for example, 1.8 mm or less, preferably 1.5 mm or less, more preferably 1.1 mm or less, even more preferably 0.9 mm or less, and most preferably 0.8 mm or less. If the surface smoothness level of the vacuum insulation material is 1.8 mm or less, highly airtight construction that takes advantage of the surface smoothness during use can be achieved, and handling is also excellent.

[0047] In the vacuum insulation material of this embodiment, when a load is applied to the vacuum insulation material in a direction parallel to the thickness direction of the resin member or vacuum insulation material by a cylindrical SUS304 stainless steel sheet having a diameter of 6 mm and a mass of 5 kg, the dent amount (mm) of the vacuum insulation material is preferably less than 7.5 mm. If Dh1 is less than 7.5 mm, the vacuum insulation material is less likely to deform and experience performance degradation even when subjected to impact in the thickness direction during handling, such as on-site installation. Dh1 is preferably less than 6.0 mm, more preferably less than 4.0 mm, even more preferably less than 2.5 mm, and most preferably less than 1.5 mm. For example, Dh1 is 0 mm or greater. In this evaluation, even if the airtight film bag present on the surface of the vacuum insulation material is torn, this is still evaluated as the dent amount. Furthermore, if a cylindrical object penetrates the vacuum insulation material in this evaluation, multiple sheets of vacuum insulation material are stacked and re-evaluated to determine Dh1.

[0048] The highly airtight bag-shaped film used to cover the resin member used to produce the vacuum insulation material is not particularly limited, and its material, size, thickness, etc. can be appropriately selected depending on the purpose. Preferred films include laminated films, particularly multilayer laminated films containing a vapor-deposited or laminated metal (e.g., aluminum) layer. Suitable films include, for example, polyester; polyvinyl chloride; polyolefins such as polyethylene or polypropylene; or polyvinyl alcohol.

[0049] The size of the vacuum insulation material depends on the size of the resin member, but can be set appropriately depending on the purpose. In the case of a substantially rectangular parallelepiped shape, one side excluding the thickness direction is preferably 30 mm to 6010 mm, more preferably 50 mm to 3010 mm, even more preferably 100 mm to 2010 mm, and most preferably 200 mm to 1210 mm. Furthermore, the thickness of the vacuum insulation material is preferably 1 mm to 120 mm, more preferably 2 mm to 80 mm, even more preferably 3 mm to 50 mm, and most preferably 5 mm to 50 mm.

[0050] The shape of the vacuum insulation material depends on the shape of the resin member, but is not particularly limited and can be any shape. Examples include rectangular parallelepipeds (e.g., plate-shaped, layered, sheet-shaped, etc.), prisms, cylinders, disks, and polyhedrons other than rectangular parallelepipeds (e.g., regular polyhedrons such as a regular tetrahedron, regular octahedron, regular dodecahedron, and regular icosahedron). In this embodiment, the term "approximately rectangular parallelepiped" refers to a rectangular parallelepiped whose surfaces are not necessarily flat, and includes curved surfaces, surfaces connected by curved surfaces, and corners that are curved.

[0051] The method for closing the bag-shaped film is not particularly limited, and known means such as heat sealing can be used. It is sufficient that the resin member is closed by the bag-shaped film, and after evacuating the inside of the bag-shaped film containing the resin member, the film is airtightly sealed. A material that absorbs moisture and other gases, such as a getter agent, may be attached or inserted into the bag as appropriate.

[0052] A vacuum insulation material is obtained by placing a resin member inside a bag-shaped film, reducing the pressure inside the bag-shaped film, and then sealing it by means such as heat sealing. The pressure inside the bag-shaped film at this time is, for example, 1 Pa to 1000 Pa, preferably 5 Pa to 500 Pa, and more preferably 10 Pa to 200 Pa. If the pressure inside the bag-shaped film is 1000 Pa or less, the thermal conductivity of the resulting vacuum insulation material at 23°C can be reduced. Furthermore, if the pressure is 1 Pa or more, damage to the bag-shaped film due to the pressure difference with atmospheric pressure can be prevented.

[0053] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these.

[0054] (Examples 1 to 3, Examples 5 to 8, Example 11, and Comparative Example 2) <Preparation of resin member raw materials A to E, and J> A phenolic resin foam (resin member raw material A) having a thickness of 45 mm was obtained in the same manner as in the production of the phenolic resin foam of Example 1 of JP 2021-192962 A, except that the number of parts of the blowing agent was 4.5 parts by mass. When the density and closed cell ratio of the phenolic resin foam were measured using the methods described below, the density was 30 kg / m３ The closed cell ratio was 93%. Similarly, the phenolic resin foams obtained by adjusting the number of parts of the foaming agent, the acidic curing agent, the free roller height in the pre-molding process, and the temperature in the main molding process were cured at 120°C for 4 hours to obtain resin member raw materials B to E and J shown in Table 1.

[0055] <Preparation of Resin Members A1-A3, B1-E1, E2, and J1> The resin member raw material was reduced in volume using a roller compactor to obtain a resin member. The roller compactor is composed of a feeder and a roller compactor. The resin member raw material is fed between an upper roller (hydraulic cylinder lift type) and a fixed lower roller, and compressed to a volume reduction ratio of 0.1 to 0.9 by the pressure between the two rollers while running at a constant speed. By adjusting the resin member raw material type (thickness) and the spacing between the upper and lower rollers, the resin members A1-A3, B1-E1, E2, and J1 listed in Table 1 were obtained. Table 2 shows the density, closed cell ratio, Dh0, and the number of connected resin skeletons surrounding the bubble film at the center position in the thickness direction of these resin members A1-A3, B1-E1, E2, and J1.

[0056] 1 is a perspective view showing a resin member according to Example 1. In FIG. 1, reference numeral 2 denotes the thickness of the resin member 1.

[0057] <Production of vacuum insulation materials A1S to A3S, B1S to E1S, E2S, and J1S> After the resin members A1 to A3, B1 to E1, E2, and J1 were cut to a size of 270 mm x 270 mm, they were placed inside an aluminum bag (polyethylene terephthalate / aluminum foil / polyethylene vapor deposition bag) manufactured by Mitsubishi Gas Chemical Company (standard AB350500PL; 350 mm x 500 mm), and then the pressure inside the aluminum bag was reduced to 130 Pa using an FVCII-G "small vacuum gas packaging machine" manufactured by Furukawa Seisakusho Co., Ltd., and the opening of the aluminum bag was sealed by heat sealing to obtain vacuum insulation materials A1S to A3S, B1S to E1S, E2S, and J1S.

[0058] Figure 2 is a perspective view showing a schematic diagram of the vacuum heat insulating material of Example 1. A resin member 1 is housed in a highly airtight bag-shaped film bag 4 of the vacuum heat insulating material 3. Figure 3 is a plan view showing a schematic diagram of the vacuum heat insulating material of Example 1.

[0059] Example 4 <Preparation of Resin Member A4> A resin member A1 was obtained in the same manner as in Example 1. Three pieces measuring 90 mm x 270 mm (one of which was designated resin member 1') were cut out from the resin member A1, yielding three specimens, designated A1(1) to A1(3). These three specimens are collectively referred to as A4. The density, closed cell fraction, Dh0, and the number of connected resin skeletons surrounding the bubble film at the center position in the thickness direction of each of A1(1) to A1(3) were evaluated, and the average values ​​of A1(1) to A1(3) were calculated to determine the density, closed cell fraction, and Dh0 of A4. After evaluating the number of connected resin skeletons surrounding the bubble film at the center position in the thickness direction for each of A1(1) to A1(3), all of them were found to have substantially no bubble structure, and therefore A4 was evaluated as a "0" result. The results are shown in Table 2.

[0060] <Preparation of Vacuum Insulation Material A4S> The three test pieces A1(1) to A1(3) were arranged in a direction perpendicular to the thickness direction to give an apparent size of 270 mm x 270 mm, and then placed inside an aluminum bag manufactured by Mitsubishi Gas Chemical Company (specification AB350500PL; 350 mm x 500 mm). The pressure inside the aluminum bag was then reduced to 130 Pa using an FVCII-G "small vacuum gas packaging machine" manufactured by Furukawa Manufacturing Co., Ltd. The opening of the aluminum bag was then sealed by heat sealing to obtain the vacuum insulation material A4S.

[0061] FIG. 5 is a plan view showing a schematic diagram of the vacuum heat insulating material of Example 4.

[0062] (Example 9) <Preparation of resin member F1> A resin member F1 was obtained in the same manner as in Example 1 using a "Q1 Board, 30 mm" manufactured by Achilles Corporation as the resin member raw material. The density, closed cell content, Dh0, and the number of connected resin skeletons surrounding the bubble film at the center position in the thickness direction of F1 were determined. The results are shown in Table 2.

[0063] <Preparation of Vacuum Insulation Material F1S> The resin member F1 was prepared in the same manner as in Example 1, except for the resin member used, to obtain a vacuum insulation material F1S.

[0064] (Example 10) <Preparation of resin member G1> Using "Styrofoam (registered trademark) IB, 30 mm" manufactured by DuPont Styro Corporation as the resin member raw material, a resin member G1 was obtained in the same manner as in Example 1. For G1, the density, closed cell content, Dh0, and the number of connected resin skeletons surrounding the bubble film at the center position in the thickness direction were determined. The results are shown in Table 2.

[0065] <Preparation of Vacuum Insulation Material G1S> The resin member G1 was prepared in the same manner as in Example 1, except for the resin member used, to obtain a vacuum insulation material G1S.

[0066] (Comparative Example 1) <Production of resin member raw material H> In the production of the phenolic resin foam of Example 1 of JP 2021-192962 A, 1.0 part of a composition containing 50% by mass of an ethylene oxide-propylene oxide block copolymer and polyoxyethylene dodecyl phenyl ether as surfactants was used relative to 100 parts by mass of the phenolic resin, and 3.5 parts of 8032 Additive manufactured by Dow Toray Industries, Inc. was added to make the moisture content 9%, and a 35 mm thick phenolic resin foam (resin member raw material H) was obtained in the same manner. The density was 33 kg / m ３ The closed cell content was 4.1%.

[0067] <Preparation of Resin Member H1> The resin member raw material H was directly prepared into a resin member (referred to as H1) without volume reduction using a roller compactor. The density, closed cell content, Dh0, and presence or absence of a substantial cellular structure at the center position in the thickness direction of this resin member H1 are shown in Table 2.

[0068] <Preparation of Vacuum Insulation Material H1S> The resin member H1 was prepared in the same manner as in Example 1, except for the resin member used, to obtain a vacuum insulation material H1S.

[0069] (Comparative Example 3) <Preparation of resin member raw material K> In the production of the phenolic resin foam of Example 1 of JP 2021-192962 A, a phenolic resin foam (resin member raw material K) having a thickness of 35 mm was obtained in the same manner as in Example 1 of JP 2021-192962 A, except that 1.75 parts of a composition containing 50% by mass of an ethylene oxide-propylene oxide block copolymer and 50% by mass of polyoxyethylene dodecyl phenyl ether as surfactants were used per 100 parts by mass of phenolic resin, and 1.75 parts of 8032 Additive manufactured by Dow Toray Industries, Inc. were added. The density and closed cell ratio of the phenolic resin foam were measured using the methods described below, and the density was found to be 31 kg / m ３ The closed cell ratio was 62%. The obtained phenolic resin foam was used as resin member raw material K.

[0070] <Preparation of resin member K1> A resin member K1 was obtained using the resin member raw material K in the same manner as in Example 1. Table 2 shows the density, closed cell content, Dh0, and whether or not a substantial cellular structure was present at the center position in the thickness direction of K1.

[0071] <Preparation of Vacuum Insulation Material K1S> The resin member K1 was prepared in the same manner as in Example 1, except for the resin member used, to obtain a vacuum insulation material K1S.

[0072] <Density of resin member raw material> A 200 mm square resin member raw material was used as a sample, and the mass and apparent volume were measured according to JIS K7222. If the resin member raw material was less than 200 mm, the size was adjusted appropriately, and the mass and apparent volume were measured to determine the density. When multiple resin member raw materials were used, the densities obtained by evaluating each were averaged to determine the "density of the resin member raw material."

[0073] <Density of Resin Member> A resin member was used as a sample, and its mass was first measured. Next, to measure the volume, four points on each of the three sides of the approximately flat plate were measured, and the average of each side was calculated, and the volume on the approximately flat plate was then calculated. When measuring each side, the thickness and even volume of some samples can change when pressed down, so measurements were performed using a ruler without using calipers to avoid pressing down on them. The density of the resin member was calculated by dividing the mass by the volume. When multiple resin members were used, the densities obtained by evaluating each of them were averaged to determine the "density of the resin member."

[0074] <Closed Cell Ratio> The closed cell ratio of the resin member was measured in accordance with ASTM-D-2856 (Method C). Specifically, for samples with a surface material, the surface material was removed from the resin member, and five approximately 1 cm cubes were cut out to include the center of the resin member in the thickness direction. The sample volume was measured using an air-comparison hydrometer (Tokyo Science, Model 1000). The volume of the cell walls (cell skeleton and cell membrane) was calculated from the sample mass and the density of the resin member. The apparent volume was calculated from the outer dimensions of the sample. The closed cell ratio was calculated by subtracting the volume of the cell walls (cell skeleton and cell membrane) from the sample volume and dividing the result by the apparent volume. The density of phenolic resin was set to 1.3 kg / L. For resins other than phenolic resin, the density should be determined appropriately after confirming the material. When multiple resin members are used, the "closed cell ratio of the resin member" was determined by averaging the closed cell ratios obtained by evaluating each of them.

[0075] <Dent depth when load is applied; Dh0> Using a vernier caliper, the thickness of the resin member was measured at four points 20 mm inward from the four corners, and the average value was taken as the thickness of the resin member. Then, the sample was placed on a smooth surface with the thickness direction facing up and down. Furthermore, as shown in FIG. 10 , the sample 9 was placed on two pieces of wood 14 arranged parallel to each other with a 20 mm gap between them, so that the overlap between the resin member 9 and each piece of wood 14 was 5 mm or more. A cylindrical stainless steel SUS304 (reference numeral 10) with a diameter of 6 mm and a mass of 3 kg was placed on top of the wire 11, which could be moved up and down by rotating a position adjustment handle 13 using a pulley 12 from above. The stainless steel 10 was then slowly lowered from above onto the sample 9 to a position corresponding to the midpoint between the two pieces of wood 14 spaced 20 mm apart. After the stainless steel 10 became self-supporting on the sample 9 and the wire 11 slackened, the sample was held for 30 seconds. Thereafter, the wire 11 was pulled up, and the amount of dent in the sample 9 was measured using a vernier caliper. For two samples 9, the upper surface side of one sample was measured, and the lower surface side of the other sample was measured, for a total of two locations, and the average value was calculated as Dh0 (mm). Note that when multiple resin members are used, the amount of dent obtained by evaluating each of them is averaged to obtain "Dh0".

[0076] <Number of connected resin skeletons surrounding the bubble membrane at the center position in the thickness direction> The thickness of the resin member (or its core material if it is a vacuum insulation material) is measured. In a photograph of a 0.25 mm x 0.25 mm field of view taken at 500 times magnification with an electron microscope, the center position in the thickness direction (half the thickness position) is in the center of the field of view, and the vertical direction of the field of view is the thickness direction of the resin member. The number of connected resin skeletons surrounding the bubble membrane in the field of view is counted. The same operation is performed three times on photographs of other parts, for a total of four measurements. The maximum value in the four measurements is evaluated as the "number of connected resin skeletons surrounding the bubble membrane." Note that the bubble membrane may be torn or have holes. Furthermore, when multiple resin components are used, the smallest number of connected resin skeletons surrounding the bubble film obtained by each evaluation is defined as the "number of connected resin skeletons surrounding the bubble film at the center position in the thickness direction."

[0077] The vacuum insulation materials obtained in the examples and comparative examples were measured for density, thermal conductivity in an environment of 23° C., surface smoothness level, and Dh1. The results are shown in Table 2.

[0078] <Density of vacuum insulation material> In the case of an approximately rectangular parallelepiped, four points on each of the three sides were measured using calipers, and the average of each side was calculated as the volume of the approximately rectangular parallelepiped. The volume of the bag-shaped film portion on the surface alone (excluding the heat-sealed portion) was ignored, and the density was calculated as the density of the location where the resin sample was located.

[0079] <Thermal Conductivity of Vacuum Insulation Material in a 23°C Environment> In accordance with JIS A 1412-2:1999, the thermal conductivity of the vacuum insulation material in the thickness direction in a 23°C environment was measured using the following method. The specific procedure is as follows. A vacuum insulation material specimen was placed in an atmosphere of 23±1°C and humidity 50±2%. After 24 hours or more had elapsed, it was introduced into a thermal conductivity device also placed in an atmosphere of 23±1°C and humidity 50±2%. The thermal conductivity measurement was performed using a single-test-piece, symmetrical configuration measuring device (Eiko Seiki Co., Ltd., product name "HC-074 / FOX304") under the conditions of a thermal conductivity at 23°C of 13°C for the low-temperature plate and 33°C for the high-temperature plate. Note that when measuring the thermal conductivity of a large vacuum insulation material or an extremely small vacuum insulation material, the measurement method is not limited to the above, and an appropriate measuring device can be selected.

[0080] <Surface smoothness level; ΔH> The thickness of the vacuum insulation material was measured using a caliper. That is, for one side, the thickness was measured at 20 different points including the center, and the difference Δhx between the maximum and minimum values ​​was calculated. Similarly, the thickness was measured at 20 different points including the center for the side perpendicular to the side, and the difference Δhy between the maximum and minimum values ​​was calculated. Then, the larger value of Δhx and Δhy was taken as ΔH and evaluated as the surface smoothness level (mm).

[0081] <Dent depth when load is applied; Dh1> Measurement was performed in the same manner as for Dh0, except that a cylindrical SUS304 stainless steel specimen having a diameter of 6 mm and a mass of 5 kg was used. Measurements were performed at two locations, one on the upper surface of one sample and the other on the lower surface of the other sample, and the average value was calculated as Dh1 (mm).

[0082] In Table 1, F: rigid urethane resin foam, G: polystyrene resin foam

[0083]

[0084] It can be seen that the vacuum insulation materials and their core materials obtained in Examples 1 to 11 have a good level of surface smoothness as vacuum insulation materials and are vacuum insulation materials and their core materials with excellent strength in the thickness direction, compared to the vacuum insulation materials and core materials obtained in Comparative Examples 1 to 3.

[0085] 1: Resin member 1': Resin member (recycled material) 2: Thickness of resin member 3: Vacuum insulation material 4: Highly airtight film bag 5: Heat-sealed section 6: Bubble skeleton 7: Bubble film 8: Resin skeleton surrounding and connecting the bubble film 9: Sample 10: Cylindrical stainless steel SUS304 11: Wire 12: Pulley 13: Position adjustment handle 14: Piece of wood

[0086] According to the present invention, it is possible to provide a vacuum insulation material and its core material that have a good level of surface smoothness as a vacuum insulation material, excellent strength in the thickness direction, and good workability.

Claims

1. A resin member having a substantially flat plate shape, wherein the density of the resin member is 50 kg / m ３ or more and 250 kg / m ３ or less, and when the amount of deflection (mm) of the resin member when a load by a cylindrical stainless steel SUS304 having a diameter of 6 mm and a mass of 3 kg is applied to the resin member in a direction parallel to the thickness direction of the resin member is defined as Dh0, the resin member has Dh0 less than 7.5 mm.

2. In a 0.25 mm × 0.25 mm field of view photograph taken by magnifying 500 times with an electron microscope such that the central position in the thickness direction of the resin member is centered in the field of view and the vertical direction of the field of view is the thickness direction of the resin member, the resin member according to claim 1, wherein the number of connected resin skeletons surrounding the bubble film is 0 or 1.

3. The resin member according to claim 1, wherein the resin member is one or more selected from the group consisting of a phenol resin, a urethane resin, and a styrene resin.

4. The resin member according to claim 1, wherein the resin member is a phenol resin.

5. A vacuum heat insulating material comprising a sealed bag and the resin member according to any one of claims 1 to 4 enclosed in the bag under a reduced pressure state.

6. The density of the vacuum insulating material is 60 kg / m ３ or more and 260 kg / m ３ or less. The vacuum insulating material according to claim 5.

7. The vacuum heat insulating material according to claim 5, wherein the thermal conductivity of the vacuum heat insulating material at 23°C is 0.010 W / (m·K) or less.

8. The vacuum heat insulating material according to claim 5, wherein the surface smoothness level of the vacuum heat insulating material is 1.8 mm or less.

9. When the amount of indentation (mm) of the vacuum heat insulating material when a load by a 6 mm diameter and 5 kg mass cylindrical stainless steel SUS304 is applied to the vacuum heat insulating material in a direction parallel to the thickness direction of the resin member is defined as Dh1, the vacuum heat insulating material according to claim 5, wherein Dh1 is less than 7.5 mm.

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