CN110388538B

CN110388538B - Vacuum heat insulation material

Info

Publication number: CN110388538B
Application number: CN201910242961.6A
Authority: CN
Inventors: 上田勉; 中礼司
Original assignee: Aqua Co Ltd
Current assignee: Aqua Co Ltd
Priority date: 2018-04-16
Filing date: 2019-03-28
Publication date: 2022-09-20
Anticipated expiration: 2039-03-28
Also published as: JP2019184020A; CN110388538A; JP7233070B2

Abstract

The invention provides a vacuum heat-insulating material which has sufficient heat-insulating performance even if being thin and can realize three-dimensional shape forming. The vacuum heat-insulating material (2) provided by the invention comprises: a core member (30) having an inner layer (10) including an inorganic fiber sheet (4) or a laminated sheet (8) formed by alternately arranging inorganic fiber sheets (4) and resin fiber sheets (6), and an outer layer (20) including resin fiber sheets (6a, 6b) arranged in contact with an upper surface (10a) and a lower surface (10b) of the inner layer (10); and an outer cover (40) for hermetically sealing the core member (30) under reduced pressure.

Description

Vacuum heat insulation material

Technical Field

The present invention relates to a vacuum heat insulator obtained by decompressing and sealing a core member with an outer cover.

Background

Vacuum insulation materials in which a core member is decompressed and sealed by an outer covering to improve insulation performance are widely used. Depending on the place where the vacuum heat insulator is installed, it may be desirable to bend the vacuum heat insulator. In order to cope with such a situation, there is proposed a vacuum heat insulating material comprising: a core portion in which a non-stretchable portion and a stretchable portion are alternately arranged, and a sheath portion surrounding the core portion (see, for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2016-176491

Disclosure of Invention

The vacuum heat insulator described in patent document 1 has a structure in which a core portion mainly composed of glass wool is sealed by an outer covering material, and therefore, if it is considered that the heat insulating property is lowered, the core portion cannot be made thin. Therefore, the core portion can be bent in a predetermined direction according to the shape and arrangement of the non-stretchable portion and the stretchable portion, but is difficult to be bent in other directions. Therefore, the desired three-dimensional shape cannot be formed.

Accordingly, an object of the present invention is to provide a vacuum heat insulating material that can solve the above-described problems, has sufficient heat insulating performance even when it is thin, and can realize three-dimensional shape forming.

The vacuum heat insulating material of the present invention is characterized by comprising:

a core member having an inner layer including an inorganic fiber sheet or a laminated sheet formed by alternately arranging inorganic fiber sheets and resin fiber sheets, and an outer layer including a resin fiber sheet arranged in contact with an upper surface and a lower surface of the inner layer; and

an outer wrapping material which hermetically seals the core member.

In the present invention, since the inorganic fiber sheet and the resin fiber sheet are in contact with each other, a plurality of minute air layers exist at the boundary portion, and thus the inorganic fiber sheet has a sufficient heat insulating performance even when it is thin. The resin fiber sheet disposed on the outermost layer of the core member is thermally deformed by heating, and can be molded into various three-dimensional shapes. In this case, although a thermal expansion difference is generated between the inorganic fiber sheet and the resin fiber sheet by heating, since the fiber sheets are in contact with each other, the contact portion is limited, and a plurality of minute air layers are present at the boundary portion, damage due to the thermal expansion difference can be suppressed.

As described above, the present invention can provide a vacuum heat-insulating material that has sufficient heat-insulating performance even when it is thin and can realize three-dimensional shape formation.

In addition, the present invention is characterized in that the resin fiber sheet has a hardness lower than that of the inorganic fiber sheet.

In the present invention, since the resin fiber sheet has a lower hardness than the inorganic fiber sheet, the resin fiber sheet is deformed more largely during evacuation in the production of the vacuum heat insulator, and a plurality of minute air layers are generated. Thereby, it has excellent heat insulating performance and can effectively suppress damage caused by a difference in thermal expansion.

In addition, the present invention is characterized in that the resin fiber sheet is formed using an olefin-based short fiber.

In the present invention, since the resin fiber sheet is formed using the olefin-based short fiber, a vacuum heat insulating material which is easy to form a three-dimensional shape, lightweight, and highly reliable can be realized. In addition, at low temperatures, the thermal conductivity of the resin fiber sheet formed using the olefin-based short fibers is reduced, and therefore the thermal insulation performance is further improved. Therefore, the vacuum heat insulator can be particularly suitably used for refrigerators, freezers, cold insulation containers, and the like.

In addition, the present invention is characterized in that the fibers of the resin fiber sheet and the inorganic fiber sheet are oriented in substantially the same direction substantially orthogonal to the thickness direction of the sheet.

In the present invention, since the fibers of the resin fiber sheet and the inorganic fiber sheet are oriented in a direction substantially orthogonal to the thickness direction of the sheet, a so-called thermal bridge, which is a thermal short circuit caused by fibers extending in the thickness direction, is not generated, and therefore, excellent heat insulating performance can be obtained. Further, since the fibers of the resin fiber sheet and the fibers of the inorganic fiber sheet are oriented in substantially the same direction, even when a difference in thermal expansion occurs, friction between the fibers of the resin fiber sheet and the fibers of the inorganic fiber sheet can be further reduced, and damage can be effectively suppressed.

In addition, the core member is disposed inside the joint portion of the outer covering.

In the present invention, since the core member can be made thin, the core member can be incorporated into an envelope-shaped outer sheet and evacuated. Thus, the vacuum insulation material having no edge portion and having the core member disposed inside the joint portion of the outer material can be realized, and therefore, the edge portion treatment of the outer material is not required, and the manufacturing process can be simplified.

Drawings

Fig. 1 is a side sectional view schematically showing a vacuum insulation material according to embodiment 1 of the present invention.

Fig. 2 is a side cross-sectional view schematically showing a boundary region between the inorganic fiber sheet and the resin fiber sheet.

Fig. 3 is a side sectional view schematically showing a vacuum insulation material according to embodiment 2 of the present invention.

Fig. 4 is a perspective view schematically showing a case where a thick core member is incorporated into an outer covering having an edge portion.

Fig. 5 is a perspective view schematically showing a case where a thin core member is inserted into an envelope-shaped outer cover.

Fig. 6 is a view (photograph) showing an example in which a concave portion is provided in a vacuum heat insulator actually manufactured by bending.

Fig. 7 is a view (photograph) showing an example of three-dimensional shaping of the vacuum heat insulator actually manufactured.

Description of the reference numerals

2 vacuum heat insulating material

4. 4a, 4b inorganic fiber sheet

6. 6 a-6 c resin fiber sheet

8-layered sheet

10 inner layer

10a upper surface

10b lower surface

20 outer layer

30 core part

40 outer coating material

102 vacuum heat insulating material

130 core component

140 outer coating material

f4, f6 fiber

Detailed Description

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The embodiments described below are intended to embody the technical idea of the present invention, and the present invention is not limited to the embodiments described below unless otherwise specified.

There are cases where components having the same functions are denoted by the same reference numerals in the respective drawings. In view of the ease of explanation or understanding of the points, the embodiments may be shown separately for ease of explanation, but the configurations shown in the different embodiments may be partially replaced or combined. In the embodiments described later, descriptions of common matters with the above embodiments are omitted, and only differences will be described. In particular, the same operational effects of the same structure will not be described in each embodiment in turn. The sizes, positional relationships, and the like of the components shown in the drawings are exaggerated for clarity of explanation.

(vacuum insulation Material according to embodiment 1 of the present invention)

Fig. 1 is a side sectional view schematically showing a vacuum insulation material 2 according to embodiment 1 of the present invention.

Referring to fig. 1, a vacuum insulation material 2 according to embodiment 1 of the present invention is configured by decompressing and sealing a core member 30 functioning as an insulation material with an outer covering 40. The exterior material 40 is a film including a resin layer.

The core member 30 has: an inner layer 10 comprising an inorganic fiber sheet 4; and an outer layer 20 including

resin fiber sheets

6a, 6b arranged in contact with the upper surface 10a and the lower surface 10b of the inner layer 10. No adhesive layer is present between the inorganic fiber sheet 4 and the

resin fiber sheets

6a and 6b, and they are in a state of being in close contact with each other by pressure reduction.

(inorganic fiber sheet)

In the present embodiment, glass wool is used as the material of the inorganic fiber sheet 4, and a wet type is particularly preferable. As for the fiber diameter of the glass wool, if the fiber diameter is small, the space between the fibers increases and the void ratio increases, so that the thermal conductivity can be reduced and the variation in the unit weight of the fibers can be reduced. On the other hand, if the fiber diameter is reduced, the entanglement of the fibers is weakened, and the strength is lowered. In view of these circumstances, the fiber diameter of the glass wool is preferably about 1 μm to 8 μm, more preferably about 3 μm to 5 μm.

With respect to the fiber length of the glass wool, if the fiber length is short, the variation in the basis weight of the fiber can be reduced. On the other hand, if the fiber length of the glass wool is short, the fibers are less entangled with each other and the strength is reduced. In view of these circumstances, the fiber length of the glass wool is preferably about 2 to 100mm, and more preferably about 3 to 50 mm.

If the fiber length is short, the fibers may be oriented in the heat insulation direction, and the heat insulation performance may be reduced by a so-called thermal bridge.

The material of the inorganic fiber sheet 4 is not limited to glass wool, and inorganic fibers such as glass fiber, alumina fiber, silica alumina fiber (silica alumina fiber), quartz fiber, asbestos, and silicon carbide fiber can be used.

(resin fiber sheet)

The resin fibers are generally formed using a thermoplastic resin. In the present embodiment, an olefin resin represented by polypropylene or polyethylene among such thermoplastic resins can be used. In particular, olefin-based short fibers having a relatively short fiber length are preferable. Among them, polypropylene nonwoven fabrics produced by the melt-blown method are more preferably used.

Also with resin fibers, if the fiber diameter is small, the space between fibers increases and the porosity increases, so the thermal conductivity can be reduced and the variation in the basis weight of the fibers can be reduced. On the other hand, if the fiber diameter is reduced, the entanglement of the fibers becomes weak, and the strength is lowered. In view of these circumstances, the fiber diameter of the resin fiber is preferably about 1 μm to 8 μm, and more preferably about 3 μm to 5 μm.

With respect to the fiber length of the resin fiber, if the fiber length is short, the variation in the basis weight of the fiber can be reduced. On the other hand, if the fiber length of the resin fiber is short, the fibers are less entangled with each other, and the strength is lowered. In view of these circumstances, the fiber length of the resin fiber is preferably about 2 to 100mm, and more preferably about 3 to 50 mm.

The material of the resin fiber sheet 6 is not limited to the case of using olefin resin fibers, and fibers of any other thermoplastic resin such as nylon, polyester, acrylic resin (acrylic resin), vinylon, and polyurethane may be used.

(exterior material)

As the outer cover 40 according to the present embodiment, a gas barrier film having a 4-layer structure as described below can be used. The outermost layer is provided with nylon, polyethylene terephthalate resin, or the like, which functions as a surface protective layer, in the order from the outermost layer to the innermost layer. Next, as the 1 st intermediate layer, aluminum-deposited PET (polyethylene terephthalate) functioning as a gas barrier layer was disposed. Next, as the 2 nd intermediate layer, an aluminum foil was disposed. Then, as the innermost layer, high-density polyethylene functioning as a sealant layer is disposed.

The outer cover 40 is not limited to the case of using the gas barrier film having the 4-layer structure, and for example, a gas barrier film having a 3-layer structure including polyethylene terephthalate resin, aluminum foil, and high-density polyethylene resin, or a gas barrier film including polyethylene terephthalate resin, ethylene-vinyl alcohol copolymer resin having an aluminum vapor deposition layer, and high-density polyethylene resin, or the like can be used.

The thickness of the outer cover 40 can be, for example, 15 μm to 200 μm.

(Heat insulation Property)

In the vacuum heat insulator, the core member is sealed in the outer cover in a depressurized state, and therefore, the influence of the convective heat transfer by the air in the outer cover is very small, and the heat transfer of the core member has a large influence on the heat insulating performance of the vacuum heat insulator.

Fig. 2 is a side cross-sectional view schematically showing a boundary region between the inorganic fiber sheet 4 and the resin fiber sheet 6. As shown in fig. 2, in the vacuum insulation material 2 according to the present embodiment, since the inorganic fiber sheet 4 and the resin fiber sheet 6 are in contact with each other at the boundary between the inner layer 10 and the outer layer 20 of the core member 30, a plurality of minute air layers exist as indicated by an arrow a. Since the air layer has high heat insulation performance, the vacuum heat insulator 2 according to the present embodiment can have sufficient heat insulation performance even when it is thin.

(Heat distortion Property)

Since the outer cover is a film having a resin layer as described above, it expands and stretches when heated. If the core member does not have an outer layer made of a resin fiber sheet and the core member including inorganic fibers and the outer cover are in direct contact with each other, when the vacuum heat insulating material is heated to be thermally deformed, the outer cover is thermally expanded and extended, but the core member including inorganic fibers is not thermally expanded so much, and therefore a difference in thermal expansion occurs at the boundary between the core member and the outer cover.

In this case, the outer covering material including the resin film is brought into close contact with the outer surface of the core member by the pressure reduction, and therefore, a large frictional force is generated between the outer covering material and the core member, and there is a possibility that the boundary portion is damaged.

On the other hand, in the present embodiment, the outer layer 20 including the

resin fiber sheets

6a, 6b is positioned between the inner layer 10 including the inorganic fiber sheet 4 and the outer cover 40. If the vacuum heat insulator 2 is heated to be thermally deformed, the resin fiber sheet 6, that is, the outer layer 20 thermally expands following the outer cover 40 including the resin film. On the other hand, at the boundary between the inner layer 10 and the outer layer 20 of the core member 30, the inorganic fiber sheet 4, i.e., the inner layer 10 does not thermally expand compared to the outer layer 20, and a difference in thermal expansion occurs at the boundary between the inner layer 10 and the outer layer 20.

However, at the boundary between the inner layer 10 and the outer layer 20, since the inorganic fiber sheet 4 and the resin fiber sheet 6 are in contact with each other, the contact portion is limited, and since a plurality of minute air layers are present at the boundary, the frictional force is small, and the sliding movement is possible to suppress damage due to the difference in thermal expansion. As described above, since no adhesive layer is present at the boundary between the inner layer 10 and the outer layer 20, the slip between the fiber sheets is not restricted.

Therefore, the vacuum insulation material 2 according to the present embodiment can be molded into various three-dimensional shapes by heating the

resin fiber sheets

6a and 6b disposed on the outermost layers of the core member 30 and thermally deforming them.

As described above, in the present embodiment, it is possible to provide the vacuum heat insulator 2 which has sufficient heat insulating performance even when it is thin and can realize three-dimensional shape molding. This enables the vacuum heat insulator 2 to be designed freely, and the market for vacuum heat insulators is expanded.

Further, the resin fiber sheet 6 preferably has a lower hardness than the inorganic fiber sheet 4. In the case where the resin fiber sheet 6 has a lower hardness than the inorganic fiber sheet 4, when the core member 30 is incorporated into the outer covering 40 and vacuum-evacuated, the inorganic fiber sheet 4 is not deformed so much, and the resin fiber sheet 6 is deformed more largely than it. Therefore, a plurality of minute spaces (see arrow a in fig. 2) are generated between the inorganic fiber sheet 4 and the resin fiber sheet 6, and thus a plurality of minute air layers can be formed. Since the air layer functions as a heat insulating layer, the vacuum heat insulator 2 can have excellent heat insulating performance even if it is thin. Further, at the boundary between the inner layer 10 and the outer layer 20, the contact portion is further defined by the air layer, and therefore damage due to a difference in thermal expansion between the inorganic fiber sheet 4 and the resin fiber sheet 6 can be effectively suppressed.

As shown in fig. 2, in the present embodiment, the fibers f6 of the resin fiber sheet 6 and the fibers f4 of the inorganic fiber sheet 4 are oriented in a direction substantially orthogonal to the thickness direction of the sheet. Thus, even if the length of the fiber is short, occurrence of a so-called thermal bridge, which is a thermal short circuit caused by the fiber extending in the thickness direction, can be suppressed, and therefore, excellent heat insulating performance can be obtained.

Furthermore, since the fibers f6 of the resin fiber sheet 6 and the fibers f4 of the inorganic fiber sheet 4 are oriented in substantially the same direction, even when a difference in thermal expansion occurs, the fibers slide more easily in the fiber longitudinal direction, the frictional force generated at the boundary between the inner layer 10 and the outer layer 20 further decreases, and damage can be suppressed more effectively.

However, the present invention is not limited to this, and the fibers f6, f4 of the resin fiber sheet 6 and the inorganic fiber sheet 4 are oriented in a direction substantially orthogonal to the thickness direction of the sheets, but may be arranged so that the fibers f6, f4 of the resin fiber sheet 6 and the inorganic fiber sheet 4 form a predetermined angle in a plan view. Although the fibers f6, f4 of the resin fiber sheet 6 and the inorganic fiber sheet 4 are oriented in a direction substantially orthogonal to the thickness direction of the sheets, the fibers f6, f4 of the resin fiber sheet 6 and the inorganic fiber sheet 4 may be arranged in random directions in a plan view. In these cases, it is expected that more air layers are provided between the resin fiber sheet 6 and the inorganic fiber sheet 4.

As described above, in the present embodiment, the resin fiber sheet 6 is formed using olefin-based short fibers. Olefin resin has excellent heat resistance, cold resistance, weather resistance, light weight and can be recycled, so that the production cost can be reduced. Thus, a lightweight vacuum heat-insulating material with high reliability, which is easy to form a three-dimensional shape, can be realized.

Further, it should be noted that the thermal conductivity of the resin fiber sheet 6 including the olefin-based short fibers is observed to be reduced at low temperatures, and the thermal insulation performance is further improved. Therefore, the vacuum heat insulator 2 according to the present embodiment is particularly suitable for use in refrigerators, freezers, cold storage containers, and the like.

(vacuum insulation Material according to embodiment 2 of the present invention)

Fig. 3 is a side sectional view schematically showing a vacuum insulation material 2 according to embodiment 2 of the present invention.

The inner layer 10 includes 1 inorganic fiber sheet 4 in the above embodiment 1, and differs in this embodiment in that: the inner layer 10 includes a 3-layered laminated sheet in which an inorganic fiber sheet 4a, a resin fiber sheet 6c, and an inorganic fiber sheet 4b are alternately arranged in this order from the upper side in the drawing. As in embodiment 1, the

resin fiber sheets

6a and 6b are in contact with the upper and

lower surfaces

10a and 10b of the inner layer 10, respectively. No adhesive layer is present between the laminated

inorganic fiber sheets

4a and 4b and

resin fiber sheets

6a, 6b, and 6c, and they are in a state of being in close contact with each other by pressure reduction.

In this way, when the inner layer 10 includes the laminated sheet 8 in which the inorganic fiber sheets 4a, the resin fiber sheets 6c, and the inorganic fiber sheets 4b are alternately arranged, a plurality of minute air layers are formed between the

inorganic fiber sheets

4a and 4b and the resin fiber sheets 6c, and therefore, the heat insulation performance is further improved.

In addition, since the boundary between the

inorganic fiber sheets

4a and 4b and the resin fiber sheet 6c in the inner layer 10 is also defined by the contact between the fiber sheets, and a plurality of minute air layers are present in the boundary, damage due to a difference in thermal expansion can be suppressed.

In addition, when the laminated sheet 8 is provided in the inner layer 10, the resin fiber sheet 6c of the laminated sheet 8 constituting the inner layer 10 is thermally deformed in addition to the

resin fiber sheets

6a and 6b constituting the outer layer 20, whereby the strength of the three-dimensional shape can be increased.

In the present embodiment, the 3-layer laminated sheet 8 in which the

inorganic fiber sheets

4a and 4b and the resin fiber sheet 6c are alternately arranged is included, but the present invention is not limited to this, and any number of laminated sheets in which any number of inorganic fiber sheets and resin fiber sheets are alternately laminated can be used. The outermost layer of the inner layer 10, which is in contact with the

resin fiber sheets

6a and 6b constituting the outer layer 20, is not necessarily an inorganic fiber sheet, and may be a resin fiber sheet. That is, there may be a case where the boundary resin fiber sheets of the inner layer 10 and the outer layer 20 contact each other.

Otherwise, since the same as in embodiment 1 above, further description is omitted.

In the vacuum heat insulator 2 according to embodiment 1 and embodiment 2, the following dimensions can be exemplified as the dimensions of the respective members before decompression. The thickness of the inner layer 10 can be exemplified by about 1mm to 8mm, and the thickness of the outer layer 20 (the total thickness of the upper and lower resin fiber sheets 6) can be exemplified by about 2mm to 5 mm. Therefore, the core member 30 has a thickness of about 3mm to 20 mm. Since the thickness of the outer cover 40 is 200 μm or less, the thickness dimension of the vacuum insulation material 2 obtained by decompression-sealing the core member 30 in the outer cover 40 is about 1mm to 15 mm.

As described above, since the vacuum heat insulator 2 according to the present embodiment is extremely thin, it can be thermally deformed into a desired shape depending on the application as will be described later.

(method for producing vacuum Heat-insulating Material)

In a typical method for manufacturing a vacuum insulation material, a sheet formed of a film having gas barrier properties is prepared, and 3 edges of the sheet are heat-welded with an opening left, thereby forming a bag-shaped outer covering. Then, the core member is loaded into the outer sheath material from the opening, vacuum is drawn and the opening portion is heat-welded, and the core member is pressure-reduced and sealed by the outer sheath material.

Fig. 4 is a perspective view schematically showing a case where the thick core member 130 is fitted into the outer cover 140 having the edge portion B as shown by the arrow B. Fig. 5 is a perspective view schematically showing a case where the thin core member 30 is inserted into the envelope-shaped outer cover 40.

As shown in fig. 4, the core member 130 of the conventional vacuum insulation material 102 has a predetermined thickness in order to obtain insulation performance. Therefore, in order to secure a space into which the core member 130 can be inserted, it is necessary to use the outer cover 140 having the edge portion B of a predetermined size obtained by heat-welding 3 sides except for 1 side which is an opening. In this case, when the opening is heat-welded after vacuum evacuation, the edge portion B not filled with the core member 130 becomes a remaining portion. Therefore, when the vacuum insulation material 102 is installed in an insulation place, there is a possibility that a hemming operation of the edge portion B occurs and the outer cover 140 is damaged during the hemming operation.

On the other hand, as shown in fig. 5, in the vacuum insulation material 2 according to the embodiment of the present invention, since the core member 30 is thin, an envelope-shaped outer cover 40 having no edge portion can be used. That is, the sheet having the gas barrier property is folded, and 2 sides other than 1 side as the opening are thermally welded and fixed (the remaining 1 side is a folded portion) as shown by an arrow C in fig. 5, thereby forming the envelope-shaped outer cover 40. Then, the core member 30 is put into the envelope-shaped outer sheet 40 from the opening, and vacuum is drawn and the opening portion is heat-welded, whereby the vacuum heat-insulating material 2 can be manufactured. In this case, no edge portion is generated, and there is no problem such as breakage generated in the hemming work or the hemming work.

As described above, in the vacuum insulation material 2 according to the embodiment of the present invention, since the core member 30 can be made thin, the core member 30 can be sealed in the envelope-shaped outer cover 40. That is, in the vacuum insulation material 2 according to the present embodiment, the core member 30 is disposed inside the joining portion C of the outer covering 40. Therefore, the edge portion is not generated, and the problem such as breakage or the like generated during the hemming operation or the hemming operation is not generated.

However, the vacuum insulation material 2 according to the embodiment of the present invention may be formed using the cover 140 having the edge portion B in which 3 sides are heat-welded. In this case, the core member can be made thin, and therefore the width of the edge portion can be made narrow.

(other embodiments)

In the vacuum insulation material 2 according to embodiment 1 and embodiment 2 described above, two

resin fiber sheets

6a and 6b are disposed in contact with the upper and

lower surfaces

10a and 10b of the inner layer 10. However, not only the

sheets

6a and 6b may be arranged above and below the inner layer 10, but also 1 sheet may be used to cover the upper and lower surfaces and side surfaces of the inner layer 10 with 1 sheet. In this case, there may be a case where only one side surface is covered with 1 sheet, and there may be a case where both side surfaces (that is, all surfaces of the interior layer 10) are covered with 1 sheet.

In the vacuum insulation material 2 according to the embodiment of the present invention, since the vacuum insulation material 2 can be formed into a desired shape depending on the installation place, for example, when the vacuum insulation material 2 is used for the interior insulation of a refrigerator, the volumetric efficiency in the refrigerator can be improved. In particular, when the vacuum heat insulator 2 is provided in the vicinity of the evaporator of the refrigerator, the vacuum heat insulator 2 is formed in advance in accordance with the uneven shape caused by the ribs and the like, so that the volumetric efficiency is improved, the work efficiency for providing the vacuum heat insulator 2 is improved, and the risk of damage during work can be reduced.

The vacuum heat insulator 2 according to the above embodiment is applicable not only to refrigerators but also to various devices such as cold insulation and heat preservation boxes, building panels, cold insulation containers for medical devices, vending machines, showcases, heat insulation helmets, hot-insulation lunch boxes, and hot water feeders.

[ examples ] A method for producing a compound

Next, a test performed to actually produce the vacuum heat insulator according to embodiment 2 will be described.

The specification of the vacuum heat insulator produced is as follows.

(1) Core member

(a) Inner layer: 3-layer laminated sheet comprising inorganic fiber sheets, resin fiber sheets and inorganic fiber sheets alternately arranged in this order

(b) Outer layer: resin fiber sheet disposed in contact with upper and lower surfaces of inner layer

(c) Inorganic fiber sheet: glass wool

Manufacturer — Changhai, Changzhou, China

Commercial code-S-VIP 120

Average thickness of 1.09mm and 120g/m ²

(c) Resin fiber sheet: olefins and process for their preparation

Manufacturer _ Nippon peacock feather corporation (Japan Vilene Company, Ltd.)

Commodity code _ OF-13042(T-1Z)

Average thickness of 1.5mm and 75g/m ²

(2) Structure of outer packaging material film

manufacturer-Jie Yi Film Corporation (J-Film Corporation)

Size ONY15 μ/VMPET12 μ/AL7 μ/LLDPE50 μ

(test 1)

First, the thermal conductivity of the vacuum insulation material was measured in accordance with JIS A1412-1. At this time, two test pieces (No.1 and No.2) were used for measurement.

(1) Test strip specification

(a) Size of

(No.1)305 mm. times.317 mm, and 4.7mm in thickness

(No.2)304mm X302 mm, thickness 4.8mm

(b) Weight (D)

(No.1)97.90g

(No.2)97.28g

(test results)

As described above, in the vacuum heat insulator according to the present example, the thermal conductivity was 0.0054W/(m · K) when the average temperature θ m was 0 ℃, and the thermal conductivity was 0.0067W/(m · K) when the average temperature θ m was 23 ℃. Therefore, it was confirmed that the vacuum insulation material has high insulation performance although the average thickness thereof is 4.75mm, which is very thin. In addition, it was also confirmed that the heat insulating performance was improved by 24% in the case where the average temperature θ m was 0 ℃ as compared with the case where the average temperature θ m was 23 ℃. That is, it was confirmed that the heat insulating performance of the vacuum heat insulator has temperature dependency, and the lower the temperature is, the higher the heat insulating performance can be obtained.

(test 2)

Next, the improvement rate of the heat insulating performance with respect to the cooling box using the existing vacuum heat insulating material or urethane foam material in the case where the vacuum heat insulating material according to the present embodiment was added was measured.

(test results)

As described above, it was confirmed that: the vacuum heat insulator according to the above-described example was added to a cooling box having a conventional vacuum heat insulator, whereby the heat insulating performance was improved by 14%. In addition, it was confirmed that: in a cooling box having a thick polyurethane material but having a high heat insulating performance, the vacuum heat insulating material according to the above example was added, and the heat insulating performance was improved by 7%. In any case, the improvement of the heat insulating performance by the vacuum heat insulating material according to the above-described example was confirmed.

(test 3)

Next, a test was performed in which the actually manufactured vacuum heat insulating material was subjected to bending or three-dimensional forming. Fig. 6 is a view (photograph) showing an example in which a concave portion is provided in a vacuum heat insulator actually manufactured by bending. Fig. 7 is a view (photograph) showing an example of three-dimensional shaping of a vacuum heat insulator actually manufactured.

As shown in fig. 6, a concave portion is provided in the central portion of the vacuum insulation material so as not to cause wrinkles. Fig. 7(a) is a perspective view of a molded article obtained by molding a vacuum heat insulator into a three-dimensional shape, (b) is a view of the molded article shown in (a) as viewed from above, and (c) is a view of the molded article shown in (a) as viewed from below. As is clear from fig. 7, it was confirmed that a vacuum heat insulator capable of forming a three-dimensional shape and having a freely designed shape could be realized.

As described above, the vacuum insulation material 2 according to the embodiment of the present invention includes the core member 30 and the outer cover 40 that reduces the pressure of the core member 30, and the core member 30 includes: an inner layer 10 including a laminated sheet 8 in which inorganic fiber sheets 4 or inorganic fiber sheets 4 and resin fiber sheets 6 are alternately arranged; and an outer layer 20 including a resin fiber sheet 6 disposed in contact with the upper surface 10a and the lower surface 10b of the inner layer 10. Therefore, even if the heat insulating material is thin, it has sufficient heat insulating performance, and the three-dimensional shape can be formed. In particular, the resin fiber sheet 6 preferably has a lower hardness than the inorganic fiber sheet 4. Thus, a plurality of minute air layers can be formed between the inorganic fiber sheet 4 and the resin fiber sheet 6, so that the core member 30 has excellent heat insulating performance even if it is thin, and damage due to a difference in thermal expansion between the inorganic fiber sheet 4 and the resin fiber sheet 6 during heating can be effectively suppressed.

The embodiments and the implementation states of the present invention have been described, and the disclosure may be changed in details of the structure, and combinations of elements or changes in the order of the elements in the embodiments and the implementation states may be realized without departing from the scope and the idea of the present invention as claimed.

Claims

1. A vacuum heat insulating material is characterized by comprising:

an outer packing material that pressure-reduces and seals the core member;

the fiber diameter of the inorganic fiber is 1-8 μm, and the fiber length is 2-100 mm;

the fiber diameter of the resin fiber is 1-8 μm, and the fiber length is 2-100 mm.

2. The vacuum insulation material according to claim 1, wherein:

the resin fiber sheet has a hardness lower than that of the inorganic fiber sheet.

3. The vacuum insulation material according to claim 1, wherein:

the resin fiber sheet is formed by olefin short fibers.

4. The vacuum insulation according to claim 2, wherein:

the resin fiber sheet is formed by olefin short fibers.

5. The vacuum insulation according to any one of claims 1 to 4, wherein:

the fibers of the resin fiber sheet and the fibers of the inorganic fiber sheet are oriented in substantially the same direction substantially orthogonal to the thickness direction of the sheet.

6. The vacuum insulation according to any one of claims 1 to 4, wherein:

the core member is disposed inside the joint portion of the outer cover.

7. The vacuum insulation according to claim 5, wherein:

the core member is disposed inside the joint portion of the outer cover.