JP2012092870A - Vacuum heat insulating material and heat insulating box using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum heat insulating material excellent in recyclability and a heat insulating property.SOLUTION: The vacuum heat insulating material 10 includes: a core material 1 where a plurality of fiber aggregates made of an organic fiber are laminated; and an outer wrapping material 2 having a gas barrier property, which stores the core material, wherein the inside of the outer wrapping material 2 is vacuum and each of average fiber diameters of the facing fiber aggregates of the core material 1 varies.

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 that is excellent in recyclability and heat insulating properties and a heat insulating box using the same.

  Heat insulation boxes are installed in refrigeration equipment such as refrigerators, freezers, vending machines, cold storages, heat storages, cold storage vehicles, vehicle air conditioners, and water heaters. Moreover, the heat insulating material using a urethane foam is used for this heat insulation box.

  In recent years, urethane foam embedded with a vacuum heat insulating material having excellent heat insulating properties has been developed in response to market demands such as energy saving and space saving and large capacity. The vacuum heat insulating material generally has a structure in which powder, foam, fiber aggregate, etc. are inserted as a core material into an outer packaging material composed of a gas barrier aluminum foil laminate film, etc., and the inside is evacuated to several Pa. It has become.

In such a vacuum heat insulating material, the heat insulating property varies depending on the material and form of the core material. For this reason, vacuum heat insulating materials using various core materials have been studied.
For example, a vacuum heat insulating material using inorganic fibers such as glass fibers and ceramic fibers as the core material (see, for example, Patent Document 1 or 2), and polypropylene fibers, polylactic acid fibers, and aramid fibers as the core material Vacuum heat insulating materials using organic fibers such as LCP (liquid crystal polymer) fibers, polyester fibers, polyethylene fibers, and cellulose fibers (see, for example, Patent Document 3 or 4) are known.

  Moreover, as a form of the core material, a cotton-like (state in which fibers are entangled irregularly and integrated) or a vacuum heat insulating material using a shape in which sheets are laminated (for example, see Patent Document 5 or 6) is known. ing.

Japanese Patent Laid-Open No. 08-28776 JP 2005-344870 A JP 2002-188791 A JP 2006-283817 A JP 2005-344832 A JP 2006-307924 A

However, since the vacuum heat insulating material described in Patent Document 1 or 2 uses inorganic fibers, the recyclability is poor. Moreover, since the vacuum heat insulating material of the said patent document 3 or 4 uses the organic fiber, the hardness of a fiber is low. For this reason, when it is made into a vacuum, a fiber will be crushed and a porosity will become low, As a result, there exists a fault that sufficient heat insulation cannot be obtained.
Moreover, since the vacuum heat insulating material of the said patent document 5 or 6 is made into cotton shape, heat | fever is easily transmitted and sufficient heat insulation is not obtained.

  This invention is made | formed in view of the said situation, and it aims at providing the vacuum heat insulating material which is excellent in recyclability and excellent also in heat insulation.

  The inventors of the present invention have intensively studied to solve the above problems, and can solve the above problems by stacking fiber assemblies having different average fiber diameters to form a core material. As a result, the present invention has been completed.

  The present invention includes (1) a core material in which a plurality of fiber assemblies made of organic fibers are laminated, and an outer packaging material that has gas barrier properties and accommodates the core material, and the inside of the outer packaging material is vacuum. In the vacuum heat insulating material, the average fiber diameters of the fiber aggregates facing the core material are different.

  This invention exists in the vacuum heat insulating material of the said (1) description whose average fiber diameter of (2) fiber aggregates is 1 micrometer-15 micrometers.

  The present invention comprises (3) an opposing fiber assembly comprising a fine fiber assembly having a thin average fiber diameter and a thick fiber assembly having an average fiber diameter larger than that of the fine fiber assembly. The density of the thick fiber aggregate is 0.08 to 0.3, and the average fiber diameter of the thick fiber aggregate is 1.5 times or more of the average fiber diameter of the fine fiber aggregate (1) Or it exists in the vacuum heat insulating material as described in (2).

  The present invention resides in (4) the vacuum heat insulating material according to the above (3), wherein the average fiber diameter of the thick fiber aggregate is 9 μm to 12 μm and the average fiber diameter of the fine fiber aggregate is 1 μm to 3 μm.

  This invention exists in the vacuum heat insulating material as described in any one of said (1)-(4) whose fiber assembly is a nonwoven fabric.

  This invention exists in the heat insulation box using the vacuum heat insulating material as described in any one of (6) said (1)-(5).

In the vacuum heat insulating material of this invention, since organic fiber is used as a fiber assembly, recyclability is excellent.
Further, by making the opposite fiber aggregates have different average fiber diameters, it becomes possible to maintain a high porosity without filling the voids between the fiber aggregates. For this reason, the heat insulation of the vacuum heat insulating material of the present invention is extremely improved. At this time, it is preferable that the average fiber diameter of a fiber assembly shall be 1 micrometer-15 micrometers. In this case, since it becomes easy to maintain a porosity, it becomes difficult for heat to transmit a fiber assembly.
Therefore, the vacuum heat insulating material is excellent in recyclability and heat insulating properties.

  In the vacuum heat insulating material of the present invention, in addition to the density of the fine fiber aggregate and the thick fiber aggregate being 0.08 to 0.3, the average of the thick fiber aggregate is relative to the average fiber diameter of the fine fiber aggregate. When the fiber diameter is 1.5 times or more, the fine fiber assembly does not follow the recessed portion of the thick fiber assembly, so that a higher porosity can be maintained. In this case, it is more effective that the average fiber diameter of the thick fiber aggregate is 9 μm to 12 μm and the average fiber diameter of the fine fiber aggregate is 1 μm to 3 μm.

  As for the vacuum heat insulating material of this invention, it is preferable that a fiber assembly is a nonwoven fabric. In this case, the handleability when laminating the fiber assembly is excellent.

  Since the above-described vacuum heat insulating material is used in the heat insulating box of the present invention, the recyclability is excellent and the heat insulating property is extremely improved.

FIG. 1 is a cross-sectional view showing an embodiment of a vacuum heat insulating material according to the present invention. 2A is a photograph of a scanning electron microscope of a fine fiber assembly in the vacuum heat insulating material according to the present embodiment, and FIG. 2B is a photograph of a scanning electron microscope of a thick fiber assembly. FIG. 3 is a perspective view schematically showing a fine fiber aggregate or a thick fiber aggregate in the vacuum heat insulating material according to the present embodiment. 4 (a) to 4 (c) are scanning electron microscope photographs of the upper surface of the embossed portion of the fine fiber aggregate or the thick fiber aggregate shown in FIG. 3, (d) and (e). These are the photographs of the scanning electron microscope of the cross section of the embossed part of the fine fiber aggregate or the thick fiber aggregate shown in FIG. FIG. 5 is a cross-sectional view showing an embodiment of a heat insulation box according to the present invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

FIG. 1 is a cross-sectional view showing an embodiment of a vacuum heat insulating material according to the present invention.
As shown in FIG. 1, the vacuum heat insulating material 10 according to the present embodiment includes a core material 1 and an outer packaging material 2 that houses the core material 1.

  In the vacuum heat insulating material 10, the inside of the outer packaging material 2 is evacuated in a state where the core material 1 is accommodated in the outer packaging material 2.

  The core material 1 preferably has a porosity of 80% or more when the inside of the outer packaging material is evacuated. When the porosity is less than 80%, heat is easily transmitted as compared to the case where the porosity is within the above range, and thus the heat insulation is reduced.

  In the vacuum heat insulating material 10, the core material 1 has a structure in which a plurality of fiber assemblies having different densities are stacked. Specifically, the core material 1 includes a fiber aggregate 11 having a thin average fiber diameter (hereinafter referred to as “fine fiber aggregate” for convenience) and a fiber aggregate having a larger average fiber diameter than the fine fiber aggregate 11. (Hereinafter referred to as “thick fiber aggregate” for convenience) 12 and 12 are alternately laminated.

The density of the fine fiber aggregate 11 and the thick fiber aggregate 12 is preferably 0.08 to 0.3 g / cm ³ . When the density of the fine fiber aggregate 11 and the thick fiber aggregate 12 is less than 0.08 g / cm ³ , there is a drawback that workability at the time of lamination is deteriorated as compared with the case where the density is in the above range, When the density of the fine fiber aggregate 11 and the thick fiber aggregate 12 exceeds 0.3 g / cm ³ , the straightness of the fibers is impaired and the heat insulation performance is reduced as compared with the case where the density is in the above range. There are drawbacks.

2A is a photograph of a scanning electron microscope of a fine fiber assembly in the vacuum heat insulating material according to the present embodiment, and FIG. 2B is a photograph of a scanning electron microscope of a thick fiber assembly.
As shown to (a) of FIG. 2, as for the vacuum heat insulating material 10, the average fiber diameter differs in the range whose density of the fine fiber aggregate 11 and the thick fiber aggregate which oppose is 0.08-0.3 g / cm < ³ >. Therefore, when the inside of the outer packaging material 2 is evacuated, the thick fiber assembly 12 does not follow the recessed portion of the fine fiber assembly 11. For this reason, the vacuum heat insulating material 10 can hold | maintain a higher porosity, without the space | gap between the fine fiber assembly 11 and the thick fiber assembly 12 being buried.
Incidentally, if the average fiber diameters of the fibers of the opposing fiber assembly are substantially the same, the other fiber assembly follows the recessed portion of the one fiber assembly, and as a result, the void 15 is buried and the porosity is small. Become.

Here, the fine fiber aggregate 11 and the thick fiber aggregate 12 are made of organic fibers. For this reason, the vacuum heat insulating material 10 is excellent in recyclability.
Specifically, examples of the fine fiber aggregate 11 include polypropylene fiber, polylactic acid fiber, aramid fiber, LCP (liquid crystal polymer) fiber, polyester fiber, polyethylene fiber, and cellulose fiber. These may be used alone or in combination. Among these, it is preferable to use a polyester fiber as the fine fiber aggregate 11 from the viewpoint of versatility.
On the other hand, examples of the thick fiber aggregate 12 include polypropylene fiber, polylactic acid fiber, aramid fiber, LCP (liquid crystal polymer) fiber, polyester fiber, polyethylene fiber, and cellulose fiber. These may be used alone or in combination. Among these, it is preferable to use a polyester fiber as the thick fiber aggregate 12 from the viewpoint of versatility.

The form of the fine fiber aggregate 11 is not particularly limited, and examples thereof include woven fabrics, knitted fabrics, braided fabrics, and nonwoven fabrics. Among these, nonwoven fabrics are preferable. In this case, handling workability at the time of lamination is excellent. In addition, the manufacturing method of a nonwoven fabric may be any of an adhesive wet / dry nonwoven fabric method, a spunbond method, a melt blown method, a needle punch method, and the like.
On the other hand, the form of the thick fiber aggregate 12 is not particularly limited, and examples thereof include woven fabrics, knitted fabrics, braided fabrics, and nonwoven fabrics. Among these, nonwoven fabrics are preferable. In this case, handling workability at the time of lamination is excellent. In addition, the manufacturing method of a nonwoven fabric may be any of an adhesive wet / dry nonwoven fabric method, a spunbond method, a melt blown method, a needle punch method, and the like.

  The average fiber diameter of the fine fiber aggregate 11 and the thick fiber aggregate 12 is preferably 1 μm to 15 μm. When the average fiber diameter of the fine fiber aggregate 11 and the thick fiber aggregate 12 is less than 1 μm, the average fiber diameter of the fine fiber aggregate 11 and the thick fiber aggregate 12 is greater than that in the above range. When the average fiber diameter of the fine fiber aggregate 11 and the thick fiber aggregate 12 exceeds 15 μm, the average fiber diameter of the fine fiber aggregate 11 and the thick fiber aggregate 12 is as described above. Compared with the case where it is within the range, there is a drawback that the amount of heat transmitted through the fiber assembly is increased, and as a result, the heat insulation is lowered.

  Here, the average fiber diameter of the thick fiber aggregate 12 with respect to the average fiber diameter of the fine fiber aggregate 11 is preferably 1.5 times or more. In this case, the difference in average fiber diameter between the fine fiber assembly 11 and the thick fiber assembly 12 is surely increased, and the gap between the fine fiber assembly 11 and the thick fiber assembly 12 is further increased.

Specifically, the average fiber diameter of the fine fiber aggregate 11 is preferably 1 μm to 3 μm, and the average fiber diameter of the thick fiber aggregate 12 is preferably 9 μm to 12 μm.
When the average fiber diameter of the fine fiber aggregate 11 is less than 1 μm, the average fiber diameter of the fine fiber aggregate 11 is less than the above range, and there is a defect that workability at the time of lamination is deteriorated, When the average fiber diameter of the fine fiber aggregate 11 exceeds 3 μm, the difference in the average fiber diameter of the opposed fiber aggregates is smaller than that in the case where the average fiber diameter of the fine fiber aggregate 11 is within the above range. As a result, the other fiber assembly follows the recessed portion of the one fiber assembly, and as a result, the porosity 15 is buried and the porosity is reduced.
Further, when the average fiber diameter of the thick fiber aggregate 12 is less than 9 μm, the difference in the average fiber diameters of the opposed fiber aggregates is compared with the case where the average fiber diameter of the thick fiber aggregate 12 is within the above range. And the other fiber assembly follows the recessed portion of one fiber assembly, and as a result, the porosity 15 is buried and the porosity is reduced, and the average fiber diameter of the thick fiber assembly 12 is reduced. When the thickness exceeds 12 μm, compared with the case where the average fiber diameter of the thick fiber aggregate 12 is within the above range, there is a drawback that the amount of heat transmitted through the fiber aggregate increases and the heat insulating property is lowered.

FIG. 3 is a perspective view schematically showing a fine fiber aggregate or a thick fiber aggregate in the vacuum heat insulating material according to the present embodiment, and FIGS. 4 (a) to 4 (c) are fine fibers shown in FIG. 3. FIG. 4 is a scanning electron microscope photograph of the upper surface of an embossed portion of an aggregate or a thick fiber aggregate, and (d) and (e) are embossed fine fiber aggregates or thick fiber aggregates shown in FIG. It is the photograph of the scanning electron microscope of the cross section of the done part. In FIG. 4, (a) is a photograph magnified 25 times, (b) is 100 times, (c) is 175 times, (d) is 100 times, and (e) is magnified 175 times.
As shown in FIGS. 3 and 4, the fine fiber aggregate 11 and the thick fiber aggregate 12 are embossed. Thereby, workability | operativity improves.
At this time, the area of the embossed surface 18 is preferably 0.15 to ^2.5 cm ² . When the area of the surface 18 to be embossed is less than 0.15 cm ² , compared to the case where the area of the surface 18 to be embossed is within the above range, the unity of fibers is eliminated, and workability at the time of lamination is increased. When the area of the surface 18 to be embossed exceeds 2.5 cm ² , the porosity of the vacuum heat insulating material is compared with the case where the area of the surface 18 to be embossed is within the above range. However, there is a drawback that the heat insulating property is lowered.

Returning to FIG. 1, the outer packaging material 2 is not particularly limited as long as it has gas barrier properties. That is, the outer packaging material 2 is not particularly limited as long as the inside can be maintained in a reduced pressure state.
For example, as the outer packaging material 2, for example, a metal foil laminated with a plastic film is used.
In this case, examples of the metal foil include an aluminum foil having a thickness of 4 to 8 μm, and examples of the plastic film include a polyethylene film and a polypropylene film.

  The vacuum heat insulating material according to the present embodiment is manufactured by housing the core material in the outer packaging material 2 and evacuating the outer packaging material 2.

  As mentioned above, the vacuum heat insulating material 10 which concerns on this embodiment uses organic fiber as a fiber assembly which comprises the core material 1, and recycles by making the fiber assembly which opposes into a thing with a different average fiber diameter. In addition to excellent properties, it also has excellent heat insulation properties.

Next, the heat insulation box according to the present embodiment will be described.
FIG. 5 is a cross-sectional view showing an embodiment of a heat insulation box according to the present invention.
As shown in FIG. 5, the heat insulating box 20 according to the present embodiment includes a main body portion 21 and a lid portion 22 that seals the main body portion 21.

The main body portion 21 has the vacuum heat insulating material 10 disposed on the bottom, the vacuum heat insulating material 10 is also disposed on the side wall, and while maintaining this state, for example, urethane foam resin is poured to embed all the vacuum heat insulating materials 10. Can be obtained.
The lid portion 22 is obtained by laminating two vacuum heat insulating materials 10 having different sizes, and pouring urethane foam resin and embedding all the vacuum heat insulating materials 10 in the same manner as the main body portion 21.

  Thus, since the vacuum heat insulating material 10 mentioned above is used for the main-body part 21 and the cover part 22, the heat insulation box 20 is excellent in recyclability, and is excellent also in heat insulation.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

For example, the vacuum heat insulating material 10 according to the present embodiment includes the core material 1 and the outer packaging material 2 that houses the core material 1, but the outer packaging material 2 may include an adsorbent.
The adsorbent is for adsorbing moisture inside the vacuum heat insulating material 10 to suppress deterioration of the degree of vacuum with time inside the vacuum heat insulating material 10. As such an adsorbent, for example, one in which calcium oxide is put in a nonwoven fabric can be mentioned.

  In the vacuum heat insulating material 10 according to the present embodiment, the fine fiber aggregates 11 and the thick fiber aggregates 12 are alternately laminated, but the thick fiber aggregates and the fine fiber aggregates are partially laminated in this order. I just need it. For example, the thick fiber aggregate, the fine fiber aggregate, and the thick fiber aggregate may be laminated in this order, or the thick fiber aggregate, the thick fiber aggregate, and the fine fiber aggregate may be laminated in this order.

  In the vacuum heat insulating material 10 according to the present embodiment, the fine fiber aggregate 11 and the thick fiber aggregate 12 are embossed, but this is not an essential process.

  The vacuum heat insulating material according to the present invention is suitably used as a heat insulating material for a refrigerator, a freezer, a vending machine, a cold storage, a heat storage, a cold storage vehicle, a vehicle air conditioner, a water heater, and the like. Moreover, according to the vacuum heat insulating material which concerns on this invention, it is excellent in recyclability and it is excellent also in heat insulation.

DESCRIPTION OF SYMBOLS 1 ... Core material 2 ... Outer packaging material 10 ... Vacuum heat insulating material 11 ... Fine fiber aggregate 12 ... Thick fiber aggregate 18 ... Surface 20 ... Heat insulation box 21 ... Main unit 22 ... Lid

Claims (6)

A core material in which a plurality of fiber assemblies made of organic fibers are laminated;
An outer packaging material having gas barrier properties and containing the core material;
With
The inside of the outer packaging material is a vacuum,
The vacuum heat insulating material from which the average fiber diameter of the said fiber assembly which the said core material opposes differs.   The vacuum heat insulating material according to claim 1, wherein an average fiber diameter of the fiber assembly is 1 µm to 15 µm. The opposing fiber assembly consists of a fine fiber assembly having a thin average fiber diameter, and a thick fiber assembly having a larger average fiber diameter than the fine fiber assembly,
The density of the fine fiber aggregate and the thick fiber aggregate is 0.08 to 0.3, and the average fiber diameter of the thick fiber aggregate is 1. The vacuum heat insulating material according to claim 1 or 2, which is 5 times or more.   The vacuum heat insulating material according to claim 3, wherein the thick fiber aggregate has an average fiber diameter of 9 μm to 12 μm, and the fine fiber aggregate has an average fiber diameter of 1 μm to 3 μm.   The vacuum heat insulating material according to any one of claims 1 to 4, wherein the fiber assembly is a nonwoven fabric.   The heat insulation box using the vacuum heat insulating material as described in any one of Claims 1-5.

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