JP2010127421A - Vacuum thermal-insulating material and thermal insulation box - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum heat insulating material excellent in handleability, heat insulating performance, and productivity, and to provide a thermal insulation box equipped with the vacuum heat insulating material. <P>SOLUTION: In the vacuum heat insulating material 1, a core material 3 is accommodated inside a gas barrier vessel 2 and the inside thereof is kept in a decompressed state. The core material 3 is structured with organic fiber assemblies 50, in which organic fibers 5 are formed in a sheet form and the organic fibers 5 are not thermally deposited with each other. These organic fibers 5 are continuous in the longitudinal direction. The core material 3 can be in a laminate structure of the organic fiber assemblies 50. The organic fibers 5 of the organic fiber assemblies 50 are made of either one of polyester, polystyrene, polypropylene, polylactic acid, aramid, and liquid crystal polymers. The thermal insulation box includes an outer box 10 and an inner box 11 arranged inside the outer box 10. The vacuum heat insulating material 1 is arranged in a gap between the outer box 10 and inner box 11. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vacuum heat insulating material and a heat insulating box, and more particularly, to a vacuum heat insulating material and a heat insulating box suitable for use in a cooling / heating apparatus.

  Conventionally, urethane has been used as a heat insulating material, but recently, a vacuum heat insulating material having better heat insulating performance than urethane is used in combination with urethane. Such vacuum heat insulating materials are used not only for refrigerators but also for refrigeration equipment such as heat insulation cabinets, vehicle air conditioners, and water heaters.

A vacuum heat insulating material is a powder, foam, fiber, etc. inserted as a core material in an outer packaging material made of gas barrier (air barrier) aluminum foil, and the inside is maintained at a vacuum level of several Pa. Yes.
Such a vacuum heat insulating material is deteriorated in heat insulation performance due to air and moisture entering from the outside, outgas generated from the core material, and moisture present in the core material itself. An adsorbent is inserted in
As core materials for vacuum heat insulating materials, there are powders such as silica, foams such as urethane, and fiber bodies such as glass. At present, however, fiber bodies having the most excellent heat insulation performance are mainly used.

  The fibrous body includes inorganic fibers and organic fibers. Examples of inorganic fibers include glass fibers and carbon fibers (see, for example, Patent Documents 1 and 8), and examples of organic fibers include polystyrene fibers, polypropylene fibers, polylactic acid fibers, aramid fibers, LCP (liquid crystal polymer) fibers, and polyethylene. Examples include terephthalate fiber, polyester fiber, polyethylene fiber, and cellulose fiber (see, for example, Patent Documents 2, 7, and 9).

  Further, the shape of the fibrous body includes a cotton-like one and a laminate of sheets (for example, see Patent Documents 3 and 4), and the sheets are laminated so that fiber orientations are alternated. There are some (see Patent Documents 5 and 6).

JP-A-8-028776 (page 2-3) Japanese Patent No. 3656028 (page 5) Japanese Patent Laying-Open No. 2005-344832 (page 3-4, FIG. 1) Japanese Patent Laying-Open No. 2006-307921 (page 5-6, FIG. 2) JP 2006-017151 A (page 3, FIG. 1) Japanese Examined Patent Publication No. 7-103955 (second page, FIG. 2) JP 2006-283817 A (pages 7-8) Japanese Patent Laying-Open No. 2005-344870 (page 7, FIG. 2) Japanese Patent No. 4012903 (page 3)

In patent documents 1-9, glass fiber, a polyester fiber, etc. are used as a core material for a vacuum heat insulating material.
Glass fiber is excellent in heat insulation performance, but it is hard and brittle, so dust may scatter during the manufacture of vacuum insulation, and may cause irritation if it adheres to the skin, mucous membrane, etc. of workers, and its handling and workability are problematic. Become. In addition, when considering recycling, for example, in a refrigerator, each product is crushed in a recycling factory, and glass fiber is mixed with urethane waste and is used for thermal recycling, but it reduces combustion efficiency and becomes a residue, etc. Recyclability is not good.

  On the other hand, organic fibers such as polyester are excellent in handleability and recyclability, but have a thermal conductivity of 0.0030 W / mK (see Patent Document 7), which is an index representing heat insulation performance, and 0.0013 W of glass fiber. Compared with / mK (see Patent Document 8), the heat insulation performance is inferior.

  For this reason, the organic fiber layer can be made thin and the fiber orientation can be made perpendicular to the heat transfer direction to improve the heat insulation performance. However, the number of laminated layers becomes several hundred or more, and the productivity is poor.

  The present invention has been made to solve the above-described problems, and provides a vacuum heat insulating material excellent in handling property, heat insulating performance, and productivity, and a heat insulating box including the vacuum heat insulating material. With the goal.

  The vacuum heat insulating material according to the present invention is a vacuum heat insulating material in which a core material is housed in a gas barrier container and the inside is in a reduced pressure state, and the core material forms an organic fiber in a sheet shape, and is organic It is composed of an organic fiber aggregate in which the fibers are not thermally welded.

  According to the present invention, since the core material is composed of a sheet-like organic fiber aggregate that is not thermally welded, a vacuum heat insulating member excellent in handleability and recyclability and excellent in heat insulating performance and the use thereof are used. An insulated box can be obtained.

[Embodiment 1: Vacuum heat insulating material]
FIG. 1 is an exploded perspective view of a vacuum heat insulating material according to Embodiment 1 of the present invention, and FIG. 2 is a side view showing fiber orientation in one sheet of the vacuum heat insulating material of FIG.
In FIG. 1, a vacuum heat insulating material 1 includes a gas barrier container 2 (hereinafter referred to as “outer packaging material”) having air barrier properties, a core material 3 enclosed in the outer packaging material 2, and a gas adsorbent 4. The inside of the outer packaging material 2 is depressurized to a predetermined degree of vacuum.

(Configuration of core material)
In FIG. 2, the core material 3 of the vacuum heat insulating material 1 is an aggregate 50 in which organic fibers 5 (5a, 5b) made of polyester are formed in a sheet shape (hereinafter also referred to as an organic fiber aggregate or a sheet-like aggregate). Formed from. The core material 2 may be formed by laminating a plurality of sheets or a single sheet.

(Organic fiber aggregate)
In FIG. 2, the organic fiber assembly 50 includes a plurality of organic fibers 5a arranged at predetermined intervals, and a plurality of organic fibers arranged at predetermined intervals in a direction orthogonal to the organic fibers 5a. 5b. At this time, the organic fiber 5a and the organic fiber 5b are in point contact. In addition, although the figure has shown the case where the organic fiber 5a and the organic fiber 5b mutually orthogonally cross, it is not limited to this.
And in order to improve heat insulation, the organic fibers 5a and 5b which comprise the organic fiber assembly 50 are not heat-welded. This is because if there is a heat-welded part, an extra heat transfer path is formed, and the heat insulation performance deteriorates.
Therefore, this invention is the sheet-like organic fiber assembly 50 formed from the organic fiber 5 which is not heat-welded. In addition, each arrow shows a heat transfer direction, and 6 shows the space | gap between organic fiber 5a, 5b.

(Fiber length of organic fiber)
The organic fibers 5 of the organic fiber assembly 50 are preferably long fibers rather than short fibers in view of heat insulation performance. Therefore, this invention is the sheet-like organic fiber assembly 50 formed from the organic fiber 5 continuous in the elongate direction.

(Material of organic fiber)
The fiber material of the organic fiber assembly 50 is polyester in the present embodiment, but may be polystyrene, polypropylene, polylactic acid, aramid, or LCP (liquid crystal polymer). Since polypropylene has low hygroscopicity, drying time and evacuation time can be shortened and productivity can be improved, and since the solid heat conduction is small, the heat insulating performance of the vacuum heat insulating material is improved. Moreover, since polylactic acid is biodegradable, the core material disassembled and separated after use of the product can be subjected to landfill treatment. Furthermore, since polystyrene, aramid, and LCP have high rigidity, shape retention is good when they are vacuum-packed and subjected to atmospheric pressure, the porosity can be increased, and improvement in heat insulation performance can be expected. In particular, since polystyrene has a small solid heat conduction, further improvement in the heat insulation performance of the vacuum heat insulating material can be expected.

(Outer packaging material)
The outer packaging material 2 of the vacuum heat insulating material 1 is made of a plastic laminate film having a gas barrier property composed of nylon (for example, 6 μm), aluminum vapor-deposited PET (for example, 10 μm), aluminum foil (for example, 6 μm), and high-density polyethylene (for example, 50 μm). Become. In addition, a laminate film that does not include an aluminum foil such as polypropylene, polyvinyl alcohol, or polypropylene can be used, and a decrease in heat insulation performance due to a heat bridge can be suppressed. The outer packaging material 5 is heat-sealed on three sides of the four sides by a seal wrapping machine.

(Production method)
The manufacturing method of the vacuum heat insulating material 1 comprised as mentioned above is demonstrated.
The organic fiber aggregate 50 is manufactured by freely dropping polyester resin heated and melted from a number of nozzles arranged in a row horizontally with respect to the width to be manufactured onto the conveyor and winding the conveyor while moving the conveyor at an arbitrary speed.
The bulk density of the organic fiber assembly 50 is adjusted by the amount of molten resin discharged and the speed of the conveyor, so that organic fiber assemblies 50 having different thicknesses can be obtained.

  Conventionally, due to handling problems, after forming the sheet of the organic fiber assembly 50, the organic fibers 5a and 5b are often heated and melted with a heat roller or the like. However, the organic fiber assembly according to the present invention is often used. No. 50 is not heat-welded as described above to reduce the heat transfer path.

Then, the obtained organic fiber assembly 50 is cut into, for example, an A4 size to form the core material 3. The number of layers to be laminated is arbitrarily set based on the thickness of the obtained organic fiber assembly 50 and the thickness of the vacuum heat insulating material 1 to be manufactured. The organic fiber 5 should have a smaller fiber diameter in view of heat insulation performance, and theoretically, the fiber diameter is desirably 10 μm or less.
Note that the organic fiber assembly 50 may not be laminated depending on the required thickness of the core material 3.

  The core material 3 formed as described above is inserted into the outer packaging material 2 that is a bag, and is fixed so that the other side of the mouth is not closed. 12 hours) Dry. Next, a gas adsorbent 4 for adsorbing residual gas after vacuum packaging, outgas from the core material 3 released over time, and permeated gas entering through the sealing layer of the outer packaging material 2 is inserted into the film bag. For example, vacuuming is performed using a Kashiwagi-type vacuum packaging machine (NPC; KT-650). The vacuuming is performed until the degree of vacuum in the chamber becomes, for example, about 1 Pa to 10 Pa, and the opening of the film bag is heat-sealed in the chamber as it is to obtain the plate-like vacuum heat insulating material 1.

(Insulation performance)
Next, the influence on the heat insulation performance by the presence or absence of the thermal welding of the organic fiber assembly 50 will be described in Examples 1 and 2 as the organic fiber assembly 50 of the present invention and Comparative Example 1 for comparison. The organic fiber 5 was a polyester having a diameter of about 10 μm.
The vacuum heat insulating material 1 was manufactured according to the manufacturing method of Embodiment 1.
At this time, in Examples 1 and 2, the vacuum heat insulating material 1 made of a sheet-like organic fiber assembly 50 formed from organic fibers continuous in the longitudinal direction without being subjected to heat welding in the manufacturing process, was compared. In Example 1, the heat insulation process was performed in the manufacturing process, and the vacuum heat insulating material which consists of a sheet-like organic fiber assembly formed from the organic fiber continuous in the elongate direction was manufactured. In addition, the core material 3 was formed with the sheet form continuous in the longitudinal direction without cutting the organic fiber assembly 50.
The organic fiber assemblies of Examples 1 and 2 and Comparative Example 1 were manufactured using a thermal conductivity meter “AutoΛ HC-073 (manufactured by Eihiro Seiki Co., Ltd.)” with an upper temperature of 37.7 ° C. The thermal conductivity at a temperature difference of 10.0 ° C. was measured. The measurement was carried out after 1 day from the evacuation step.
Here, the average fiber diameter was an average value of 10 measured values measured using a microscope.

  FIG. 3 is a diagram showing the relationship of the heat insulating performance of the vacuum heat insulating materials of Examples 1 and 2 and Comparative Example 1. The horizontal axis represents the weight (unit weight) per unit area, and the vertical axis represents the heat insulation performance ratio. In addition, the heat insulation performance ratio of Examples 1 and 2 is a numerical value obtained by dividing the thermal conductivity of Comparative Example 1 by the thermal conductivity of Examples 1 and 2 (comparing the reciprocal of the thermal conductivity of Examples 1 and 2). The same as the value obtained by dividing by the reciprocal of the thermal conductivity of Example 1). In this case, the heat insulation performance ratio of Comparative Example 2 is 1.

  In Examples 1 and 2, unlike Comparative Example 1, there is no thermal welding between the organic fibers 5 of the organic fiber assembly 50, but the heat path is shortened accordingly. Therefore, as shown in FIG. 3, in Example 1, 2, heat insulation performance improves more. Further, as can be seen from Example 2, since the heat insulation performance is improved even if the basis weight is high, the number of stacked layers can be reduced, and the productivity is excellent.

Next, about the influence on the heat insulation performance by the difference in the fiber length of an organic fiber assembly, Example 3 as the organic fiber assembly 50 of the present invention and Comparative Example 2 for comparison will be described.
At this time, in Example 3, the vacuum heat insulating material 1 made of the sheet-like organic fiber assembly 50 formed from the organic fibers 5 continuous in the longitudinal direction without performing heat welding was manufactured, and in Comparative Example 2, The vacuum heat insulating material which consists of an organic fiber assembly which is a short fiber, without heat-welding was manufactured.
The method for measuring the thermal conductivity is the same as that shown in the first embodiment.

The heat insulating performance of the vacuum heat insulating material 1 of Example 3 was 1.9 times that of the vacuum heat insulating material of Comparative Example 2.
This is because the organic fiber 5 is likely to be oriented in the plane direction perpendicular to the heat insulation direction due to the long fiber length of the organic fiber assembly 50, that is, the path of solid heat transfer in the vacuum heat insulating material 1 in the heat insulation direction. This is because the heat insulating performance is improved because the length can be increased.
Therefore, the vacuum heat insulating material 1 using the organic fiber aggregate 50 formed from organic fibers continuous in the longitudinal direction instead of the short fibers as the core material 3 is superior in heat insulating performance.

[Embodiment 2: Refrigerator]
FIG. 4 is a cross-sectional view of a refrigerator (heat insulation box) according to Embodiment 2 of the present invention.
In FIG. 4, the refrigerator which is a heat insulation box includes an outer box 10, an inner box 11 arranged inside the outer box 10, a vacuum heat insulating material 1 and polyurethane arranged in a gap between the outer box 10 and the inner box 11. A foam 12 and a refrigeration unit (not shown) for supplying cold heat to the inner box 11 are provided. The outer box 10 and the inner box 11 each have an opening (not shown) formed on a common surface, and an opening / closing door (not shown) is provided in the opening.

In the above refrigerator, since the outer packaging material 2 of the vacuum heat insulating material 1 includes an aluminum foil (see FIG. 1), there is a possibility that a heat bridge in which heat flows around the aluminum foil may occur. For this reason, in order to suppress the influence of a heat bridge, the vacuum heat insulating material 1 is arrange | positioned away from the coated steel plate of the outer case 10 using the spacer 13 which is a resin molded product.
In addition, the spacer 13 is appropriately provided with holes for preventing the flow so that voids do not remain in the polyurethane foam 12 to be injected into the heat insulating wall in a later step.
That is, the refrigerator has a heat insulating wall 14 formed by the vacuum heat insulating material 1, the spacer 13 and the polyurethane foam 12. The range in which the heat insulating wall 14 is disposed is not limited, and may be the entire range of the gap formed between the outer box 10 and the inner box 11 or may be a part thereof. , May be arranged inside the opening / closing door.

When the refrigerator configured as described above is used, it is dismantled and recycled at recycling centers in various places based on the Home Appliance Recycling Law.
At this time, when the core material of the vacuum heat insulating material of the refrigerator is an inorganic powder as in the conventional case, when the crushing process is performed, the powder is scattered, and the crushing process cannot be performed as it is in the box. It takes a lot of work to remove the vacuum insulation from the body.
In addition, when the core material of the vacuum heat insulating material of the refrigerator is glass fiber as in the past, it can be crushed as it is in the box, and the crushed glass fiber is mixed with the pulverized polyurethane foam for thermal recycling. At this time, however, there is a difficulty in recyclability such as lowering the combustion efficiency or becoming a residue after combustion.
On the other hand, in this invention, since the refrigerator has the vacuum heat insulating material 1 in which the core material 3 formed by the organic fiber aggregate 50 is disposed, the crushing process is performed without removing the vacuum heat insulating material 1. It does not reduce combustion efficiency or become a residue during thermal recycling, and is highly recyclable.

In the above description, the case where the heat insulation box is a refrigerator has been shown, but the present invention is not limited to this, and cold or hot equipment such as a heat storage, a vehicle air conditioner, and a water heater, Instead of a box having a predetermined shape, a heat insulating bag (heat insulating container) having a deformable outer bag and an inner bag may be used.
In these cases, the heat insulating box may be provided with temperature adjusting means to adjust the temperature inside the inner box.

It is a disassembled perspective view of the vacuum heat insulating material which concerns on Embodiment 1 of this invention. It is a side view which shows the orientation of the fiber in the sheet | seat of the vacuum heat insulating material of FIG. It is a diagram which shows the relationship between the fabric weight of a vacuum heat insulating material, and a heat insulation performance ratio. It is sectional drawing of the refrigerator which concerns on Embodiment 2 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Vacuum heat insulating material, 2 Outer packaging material (gas barrier container), 3 Core material, 4 Gas adsorbent, 5 (5a, 5b) Organic fiber, 10 Outer box, 11 Inner box, 13 Spacer, 50 Organic fiber aggregate.

Claims (8)

It is a vacuum heat insulating material in which a core material is housed in a gas barrier container and the inside is in a reduced pressure state,
The vacuum heat insulating material characterized by the said core material being comprised by the organic fiber aggregate | assembly which forms the organic fiber in a sheet form, and the said organic fibers are not heat-welded.   The vacuum heat insulating material according to claim 1, wherein the organic fibers are continuous in the longitudinal direction.   The vacuum heat insulating material according to claim 1 or 2, wherein the core material has a laminated structure of the organic fiber assembly.   The vacuum heat insulating material according to any one of claims 1 to 3, wherein the organic fiber of the organic fiber aggregate is any one of polyester, polystyrene, polypropylene, polylactic acid, aramid, and liquid crystal polymer. An outer box, and an inner box disposed inside the outer box,
The heat insulation box characterized by arrange | positioning the vacuum heat insulating material in any one of Claims 1-4 in the clearance gap between the said outer box and an inner box.   The heat insulation according to claim 5, wherein a heat insulating material is filled in both or any one of the outer box and the vacuum heat insulating material and the inner box and the vacuum heat insulating material. box.   The heat insulating box according to claim 5 or 6, wherein a spacer is disposed between the outer box and the vacuum heat insulating material.   The heat insulation box according to any one of claims 5 to 7, wherein an internal temperature of the inner box is adjusted by a temperature adjusting means.

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