JP2016148418A - Sheath material for vacuum heat insulation material and evaluation method of sheath material for vacuum heat insulation material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum heat insulation material having sufficient stretching and bending resistance in actual use, provide a method for evaluating stretching and bending resistance of a sheath material for a vacuum heat insulation material in a state of being close to an actual use condition in the vacuum heat insulation material, and provide flexibility determination reference of the sheath material for a vacuum heat insulation material.SOLUTION: A sheath material for a vacuum heat insulation material subjects a heat insulation material to vacuum sealing to form a vacuum heat insulation material. The sheath material includes at least a rein base material, a barrier layer, and a thermal fusion resin layer. An inner pressure change amount of a specimen obtained by filling a bag, formed by making the sheath material into a bag shape, with spherical bodies, and performing vacuum sealing is 100 Pa/day or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vacuum heat insulating material exterior material used for a vacuum heat insulating material attached to a refrigerator, a low temperature container or a wall material of a house, and a method for evaluating the same.

  Various heat insulating materials have been used for refrigerators, low-temperature containers, or residential wall materials. Especially, in recent years, inorganic fiber sheets such as glass wool and porous silica have been used as heat insulating materials with excellent heat insulating performance. The vacuum heat insulating material of the structure which wrapped the core material wrapped with the nonwoven fabric with the exterior material, and was vacuum-sealed is used.

  As the structure of the vacuum heat insulating material, a laminate including a resin base material (protective layer), a barrier material (barrier layer), and a heat-fusible resin (sealant layer) is generally used. . Such an exterior material is required to have excellent barrier properties that prevent entry of water vapor and gas from the outside in order to keep the inside in a vacuum state for a long time.

  Further, the exterior material is required to have strength against extension and bending (maintenance of gas barrier performance). This is because the exterior material is subjected to elongation and bending stress due to irregularities generated when glass wool or porous silica as a core material is vacuum-sealed, and molding to a specified size. Even if it is excellent in the initial barrier property, if the barrier property after bending or stretching is inferior, it is difficult to apply as a vacuum heat insulating material.

  As an evaluation method of a film assuming such bending and stretching, a gelbo test (Patent Documents 1 to 4) is common, but when a vacuum heat insulating material is assumed as an application, the test is severe. It can be said. Therefore, there was a possibility that the quality would be excessive and the development cost would increase.

Japanese Patent No. 3068106 Japanese Patent No. 3068107 Japanese Patent No. 3095153 Japanese Patent No. 3070702

  This invention is made | formed in view of said situation, and makes it a subject to provide the vacuum heat insulating material provided with sufficient extending | stretching and bending resistance at the time of actual use. It is another object of the present invention to provide a method for evaluating the stretching / bending resistance of a vacuum heat insulating exterior material in a state close to actual use conditions as a vacuum heat insulating material.

  The vacuum insulation material exterior material of the present invention is a vacuum insulation material exterior material for vacuum-sealing the insulation material to form a vacuum insulation material, wherein the vacuum insulation material exterior material is at least a resin base material, A barrier layer and a heat-sealable resin are provided. The amount is 100 Pa / day or less.

  The method for evaluating a packaging material for a vacuum heat insulating material according to the present invention is a method for evaluating a packaging material for a vacuum heat insulating material for vacuum-sealing the heat insulating material to form a vacuum heat insulating material. Is made into a bag shape, a plurality of spherical bodies are filled into a vacuum sealed test body, and the amount of change in internal pressure of the test body is measured.

According to the vacuum heat insulating exterior material of the present invention, when the amount of change in internal pressure is 100 Pa / day or less, the core material is enclosed because damage such as cracks due to the spherical body is suppressed at a certain level. Thereafter, sufficient gas barrier performance can be maintained even after 10 years.

According to the method for evaluating a vacuum insulation material according to the present invention, as a vacuum insulation material exterior material that could not be evaluated by the MOCON method, which is a general method for evaluating the gas barrier performance of a laminate or gas barrier, The suitability of can be evaluated. More specifically, the flexibility of the laminate (change in the degree of vacuum after enclosing the core material) can be evaluated in a state close to the actual usage environment, and an appropriate evaluation result can be obtained without excessive quality. Can do.

It is a section schematic diagram showing one embodiment of the exterior material for vacuum heat insulating materials of the present invention. It is the cross-sectional schematic which shows one Embodiment of the vacuum heat insulating material using the exterior material for vacuum heat insulating materials of this invention. It is the figure which showed the outline of the apparatus for performing the evaluation method of the vacuum heat insulating material of this invention.

Hereinafter, the present invention will be specifically described with reference to the drawings.
<Exterior material for vacuum insulation>
As shown in FIG. 1, the vacuum insulating material exterior material 10 of the present invention is composed of a laminate in which a resin base material 1, a barrier layer 2, and a heat-fusible resin 3 are sequentially laminated. In addition, as a method of laminating | stacking the resin base material 1, the barrier layer 2, and the heat-fusible resin 3 one by one, the well-known method through an adhesive agent between each layer can be used, for example.

  2 shows a cross-section of a vacuum heat insulating material 20 formed by vacuum-sealing a heat insulating material (core material) 30 inside the vacuum heat insulating material exterior material 10 of the present invention shown in FIG. Yes. Specifically, the package is formed by heat sealing with the heat-fusible resin 3 (sealant) surface of the vacuum heat insulating material exterior 10 inside, and after the heat insulating material (core material) 30 is put therein, the vacuum is formed. The vacuum heat insulating material 20 is formed by sealing (sealing by heat sealing while degassing).

  The resin substrate 1 according to the present invention functions as a protective layer, and can be used as long as it is a resin substrate that is resistant to external wear, piercing, and the like, and is not particularly limited. For example, a stretched polyethylene terephthalate film, a stretched polypropylene film, a stretched nylon film, etc. are used. Although there is no particular limitation on the thickness, a stretched polyethylene terephthalate film is about 6 μm to 30 μm, a stretched polypropylene film is about 20 μm to 40 μm, and a stretched nylon film is about 10 μm to 30 μm.

  The lamination method of the resin base material 1 and the barrier layer 2 may be bonded by a dry lamination method (including a solventless lamination method) or may be bonded by a sandwich lamination method.

  The barrier layer 2 is a central layer that bears the barrier property of the vacuum heat insulating material 20, and an aluminum foil or a metal vapor-deposited film excellent in barrier property can be used. Among these, an aluminum alloy containing 0.05 wt% or more and 0.3 wt% or less of silicon and 0.7 wt% or more and 1.7 wt% or less of iron is preferable.

  The aluminum foil made of the above aluminum alloy is softer and more elongated than an aluminum foil having a high purity, so that the aluminum foil itself is less likely to cause pinholes and cracks. As such an aluminum foil, there are aluminum foils of alloy number A8021 and alloy number A8079, and those having a film thickness of about 7 to 20 μm are preferable.

  Moreover, as a barrier layer of a metal vapor deposition system, a water vapor transmission rate of 0.5 g / m 2 / day or less with a vapor deposition layer of alumina, silica or the like based on a general-purpose film such as PET is preferable, and the film thickness of the base film is A suitable thickness is about 6 to 30 μm, and the vapor deposition layer is about 10 to 300 nm.

  The heat-fusible resin 3 functions as a so-called sealant, is located in the innermost layer of the vacuum heat insulating material 20, and seals the filled core material by heat welding. A thermoplastic resin is mainly used, and a polyolefin resin is particularly preferably used.

  Polyolefin resins include low density polyethylene resins, linear low density polyethylene resins, medium density polyethylene resins, ethylene-α-olefin copolymer resins and other ethylene resins, homopolypropylene resins, and propylene-ethylene random copolymers. It is possible to select a propylene resin such as a polymer, a propylene-ethylene block copolymer, and a polypropylene-α-olefin copolymer.

  Lamination of the heat-fusible resin 3 and the barrier layer 2 may be carried out by an adhesive using a dry lamination method (including a solventless lamination method), or by a sandwich lamination method. . Furthermore, the thermoplastic resin may be melted without using an adhesive and bonded to the barrier layer by an extrusion laminating method.

  As the adhesive used in the present invention, a urethane resin adhesive is preferably used. In particular, a urethane resin two-component curable adhesive is preferable, and the adhesion between layers is preferably laminated by a dry lamination method. In particular, in order to adhere a web-like material, it is preferable to laminate by a dry laminating method using a urethane resin two-component curable adhesive.

<Vacuum insulation>
Next, the vacuum heat insulating material 20 formed by vacuum-sealing the heat insulating material (core material) 30 in the inside thereof using the vacuum heat insulating material exterior material 10 of the present invention will be described.

As a specific method for producing the vacuum heat insulating material 20, first, a package is formed using the vacuum heat insulating material exterior material 10.
As a method of forming the package, the two heat insulating resin 5 (sealant) surfaces are opposed to each other using two vacuum insulating material exterior members 10 cut into a predetermined size, and the opening other than the opening for inserting the heat insulating material 30 is used. Is obtained by fusing the periphery by heat sealing.

Further, for example, as another method, using one vacuum heat insulating material exterior member 10 cut to a predetermined size, the heat fusible resin 3 (sealant) faced inward, and then the same as described above. Other than the opening for inserting the heat insulating material 30, the periphery can be fused by heat sealing.
Next, after inserting the heat insulating material (core material) 30 from the opening of the package, the vacuum heat insulating material 20 can be manufactured by heat-sealing and sealing the opening while degassing.

As long as the heat insulating material (core material) 30 is capable of leaving a decompressed space without being crushed even if it is pressed by the vacuum heat insulating exterior material 10 by deaeration in the process of manufacturing the vacuum heat insulating material 20. It is not particularly limited.
For example, needle-like short fiber powder with a small bulk density formed by cutting inorganic fibers such as glass wool, glass fiber, alumina fiber, silica alumina fiber, silica fiber, rock wool, silicon carbide fiber, or powder such as silica or pearlite. A molded body molded into a fixed shape, an inorganic molded body of a calcium silicate molded body, or an open-cell synthetic resin foam such as foamed polyurethane or foamed polystyrene is used.
Among them, porous silica gel particles having a high porosity are preferable, and those having a porosity of 70% or more and a particle diameter of 50 μm or less are particularly preferable. When the porosity is 70% or less, it becomes difficult to impart heat insulation under vacuum. When enclosing fine particles and fine fibers in the exterior material, it is preferable to wrap the heat insulating material in advance in a breathable bag (nonwoven fabric or the like).

The vacuum insulation material exterior material of the present invention is a vacuum insulation material exterior material for vacuum-sealing the insulation material to form a vacuum insulation material, wherein the vacuum insulation material exterior material is at least a resin base material, A barrier layer and a heat-fusible resin are provided, and the outer packaging material for the vacuum heat insulating material is filled with a spherical body in a bag in which the bag is made, and then the internal pressure change of the test body obtained by vacuum-sealing. The amount is preferably 100 Pa / day or less.
It is preferable for the amount of change in internal pressure to be 100 Pa / day or less because it has flexibility to prevent damage such as cracks due to spherical bodies at a certain level. It is more preferable that the amount of change in the internal pressure is 50 Pa / day or less because it has flexibility at a level that makes it difficult to receive damage such as cracks due to the spherical body.

<Evaluation of vacuum insulation exterior materials>
Hereinafter, the evaluation method of the vacuum heat insulating material of this invention is demonstrated.
First, the vacuum heat insulating material is formed into a bag shape. As in the case of actually manufacturing a vacuum heat insulating material, an opening for filling the contents is provided. In the evaluation of the present invention, a spherical body is filled instead of the core material. After filling a sufficient amount of the spherical body, the opening is heat-sealed while degassing from the opening to obtain a test body.

The degree of vacuum of the specimen thus obtained is measured.
For example, a measuring instrument combining a vacuum chamber 101, a vacuum pump unit 102, a vacuum meter 103, a laser displacement meter 104, and a data logger 105 is used (FIG. 3).
The vacuum chamber 101 is connected to a vacuum pump unit 102 and a vacuum meter 103. The vacuum chamber 101 is provided with a window that can be observed from the outside, and is covered with glass. The laser displacement meter 104 is for measuring the displacement of the outer shape of the test body 110 in the vacuum chamber 101, and is connected to the data logger 105. The laser 107 can irradiate the test body 110 through the glass window 106.

  When the test body 110 is placed in the vacuum chamber 101 and evacuation is started, the shape of the test body 110 changes when the pressure inside the vacuum chamber 101 becomes lower than the pressure inside the test body 110. Specifically, it expands because the atmospheric pressure drops. This displacement is detected by a laser displacement meter 104, and the atmospheric pressure at the start of the displacement is recorded as the degree of vacuum inside the specimen (lift-off method). Since the change in the degree of vacuum is so small that it is resistant to stretching / bending, the change in the degree of vacuum can be used for evaluating the stretching / bending resistance of the exterior material (hereinafter, sometimes simply referred to as bendability).

The spherical body used in the measurement of the present invention is preferably a spherical body having a diameter of 3 to 20 mm, particularly preferably 5 to 10 mm. Within this range, the spherical body has a curve close to the shape required for an actual vacuum heat insulating material, so that realistic stretching / bending resistance can be evaluated. If the diameter of the spherical body is larger than 20 mm, the stretching / bending width given to the exterior material becomes excessive, the change in the degree of vacuum becomes too large, and there is a possibility that accurate measurement becomes difficult. If the diameter of the spherical body is smaller than 3 mm, the spherical body is dispersed along the outer shape of the exterior material, and the stretching / bending width is reduced, so that the change in the degree of vacuum is small and the evaluation takes time.
It is preferable that the size of the spheres used at the same time is the same, but within a suitable range (3 mm or more and 20 mm or less, preferably 5 mm or more and 10 mm or less), a mixture of spheres of a plurality of sizes can be mixed. Can be used.
The spherical body is filled to such an extent that the vacuum insulation material is not deformed. After the vacuum sealing, the exterior material may be stretched and bent along the spherical surface shape. As the shape of the spherical body, it is preferable that there is no extreme unevenness or distortion for accurate measurement of stretching / bending resistance. In order to accurately measure the degree of vacuum, the material preferably does not degas during vacuum sealing, and is preferably glass or metal. For example, glass beads can be used.

  Hereinafter, the present invention will be specifically described by way of examples.

<Example 1>
(Preparation of vacuum insulation exterior materials)
A stretched nylon film with a thickness of 15 μm (made by Unitika, Emblem ONM) as a resin base material, an aluminum foil with a thickness of 9 μm (Toyo Aluminum, 8021 alloy) as a barrier layer, and a 40 μm film as a heat-fusible resin (sealant) Using a thick linear low-density polyethylene film (Mitsui Chemicals Tosero, TUX-FCS), each layer is made from a polyester polyurethane base (DIC, LX500) and an aromatic isocyanate curing agent (DIC, KW75). A laminated body (exterior material for vacuum heat insulating material) was produced by sequentially laminating with an adhesive as described above by a dry laminating method.

(Evaluation of flexibility)
The vacuum insulating material exterior material obtained above was cut into 200 mm square, the sealant surface was bonded to the inside, and a three-side sealed bag with a seal width of 10 mm was produced. Thereafter, a glass spherical body having a diameter of 10 mm was sealed in the bag, and sealed with a vacuum sealing device at a vacuum degree of 10 Pa. The initial internal pressure of this vacuum-sealed product was measured by the lift-off method, and then stored in an environment of 25 ° C. and 40% RH, and the change over time in internal pressure (Pa / day) was measured. As a result, the result of increasing the degree of vacuum at 3 Pa / day was obtained. The increase in the degree of vacuum when there was no content was 0.3 Pa / day.

<Example 2>
(Preparation of vacuum insulation exterior materials)
As the base film (resin substrate), a stretched polyethylene terephthalate film (E5100, manufactured by Toyobo Co., Ltd.) having a thickness of 12 μm was used. On one surface of the base film, a resin solution composed of acrylic polyol and tolylene diisocyanate was applied using a micro gravure coater so as to have a dry film thickness of 30 nm, thereby forming an anchor coat layer. Next, an SiOx film is formed by DC sputtering using Si as a target on the surface on which the anchor coat layer has been formed, using Ar as a process gas, and O2 as a reactive gas so as to have a film thickness of 50 nm. Formed.
In the same manner as in Example 1, on this barrier layer, a heat-bonding property is obtained by a dry laminating method through an adhesive composed of a polyester polyurethane main agent (manufactured by DIC, LX500) and an aromatic isocyanate curing agent (manufactured by DIC, KW75). A 40 μm-thick linear low-density polyethylene film (manufactured by Mitsui Chemical Tosero, TUX-FCS) was laminated as a resin (sealant) by a dry laminating method to produce a laminate (exterior material for vacuum heat insulating material).

(Evaluation of flexibility)
A change in the degree of vacuum was measured in the same manner as in Example 1. As a result, the degree of vacuum increased at 25 Pa / day. The increase in the degree of vacuum when there was no content was 1 Pa / day.

<Example 3>
(Preparation of vacuum insulation exterior materials)
A laminate (exterior material for vacuum heat insulating material) was produced in the same manner as in Example 2 except that the SiOx film was formed so that the film thickness by DC sputtering was 100 nm.

(Evaluation of flexibility)
A change in the degree of vacuum was measured in the same manner as in Example 1. As a result, the degree of vacuum increased at 40 Pa / day. The increase in the degree of vacuum when there was no content was 0.6 Pa / day.

<Example 4>
(Preparation of vacuum insulation exterior materials)
A laminate (exterior material for vacuum heat insulating material) was produced in the same manner as in Example 2 except that the SiOx film was formed to have a film thickness of 200 nm by DC sputtering.

(Evaluation of flexibility)
A change in the degree of vacuum was measured in the same manner as in Example 1. As a result, the degree of vacuum increased at 60 Pa / day. The increase in the degree of vacuum when there was no content was 0.3 Pa / day.

<Comparative Example 1>
(Preparation of vacuum insulation exterior materials)
A laminate (exterior material for vacuum heat insulating material) was produced in the same manner as in Example 2 except that the SiOx film was formed so that the film thickness by DC sputtering was 400 nm.

(Evaluation of flexibility)
A change in the degree of vacuum was measured in the same manner as in Example 1. As a result, the degree of vacuum increased at 300 Pa / day. The increase in the degree of vacuum when there was no content was 0.1 Pa / day.

  From the above results, according to the present invention, it is possible to evaluate the flexibility of the exterior material under conditions close to actual use without falling into excessive quality.

DESCRIPTION OF SYMBOLS 1 ... Resin base material 2 ... Barrier layer 3 ... Heat-sealable resin 10 ... Vacuum insulation material exterior material 20 ... Vacuum insulation material 30 ... Heat insulation material (core material)
DESCRIPTION OF SYMBOLS 101 ... Vacuum chamber 102 ... Vacuum pump unit 103 ... Vacuum meter 104 ... Laser displacement meter 105 ... Data logger 106 ... Glass window 107 ... Laser beam 108 ... Computer (PC)
110 ... Specimen (vacuum insulation)

Claims (3)

A vacuum insulation material exterior material for vacuum-sealing the insulation material to form a vacuum insulation material,
The exterior material for vacuum heat insulating material includes at least a resin base material, a barrier layer, and a heat-fusible resin,
The vacuum insulating material exterior material is characterized in that the amount of change in the internal pressure of a test body obtained by vacuum sealing after filling a spherical body into a bag made from the bag is 100 Pa / day or less. Exterior material for vacuum insulation. It is a method for evaluating a vacuum heat insulating material exterior material for vacuum-sealing a heat insulating material to form a vacuum heat insulating material,
A vacuum characterized in that a vacuum insulation material is made into a bag shape, a plurality of spherical bodies are filled inside and vacuum sealed to create a test body, and the amount of change in internal pressure of the test body is measured. Thermal insulation exterior material evaluation method.   The said spherical body is a spherical shape with a diameter of 3-20 mm, The exterior material evaluation method for vacuum heat insulating materials of Claim 2 characterized by the above-mentioned.

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