JP5884419B2 - Jacket material for vacuum heat insulating material and vacuum heat insulating material using the same - Google Patents

Description

  The present invention relates to a vacuum heat insulating jacket material for a vacuum heat insulating material attached to a refrigerator, a low temperature container, a housing outer wall material, or the like, and a vacuum heat insulating material using the same.

  Various heat insulating materials have been used for refrigerators, low-temperature containers, and external wall materials in houses. Especially, as a heat insulating material with excellent heat insulating performance, the core material is enclosed in the jacket material and the inside is vacuumed. An evacuated vacuum insulation material is used.

This jacket material needs to be excellent in gas barrier properties in order to prevent gas from entering from the outside and keep the inside in a vacuum state for a long time. Therefore, conventionally, in order to have a high gas barrier property, a laminated film including a metal aluminum foil having a thickness of about 7 to 15 μm has been mainly used as a gas barrier layer of a covering material.

  This metal aluminum foil has a problem that cracks and pinholes are generated by bending and the gas barrier property is remarkably lowered, and it is difficult to keep the inside of the jacket material in a vacuum state for a long period of time.

  Attempts have been made to reduce the occurrence of cracks and pinholes and maintain the vacuum state inside the jacket material for a long period of time. For example, the layer configuration is, in order from the outside, a first stretched nylon film, a second stretched nylon film, a gas barrier layer made of metal foil, and a heat-welded layer, and is bonded between the first and second stretched nylon films. There was a jacket material provided with a layer (Patent Document 1).

  In addition, the thermal weld layer is a plastic film having a tensile elongation in the longitudinal direction and in the transverse direction of 400% or more and a tensile elongation in the longitudinal direction that is not more than twice the tensile elongation in the transverse direction. There was a jacket material using a linear low density polyethylene film of 0.935 or more (Patent Document 2).

  Known documents are shown below.

Japanese Patent No. 3482408 Japanese Patent No. 4207476

  Metal foil such as aluminum foil has almost no elongation, and when it is extended by piercing or bending, pinholes and cracks are easily generated, the barrier property is remarkably lowered, and the heat insulating effect as a vacuum heat insulating material is lowered. . In the above-mentioned patent documents, it is difficult to suppress the generation of pinholes generated in the aluminum foil, and further improvements have been demanded.

  The present invention has been made in view of the above-described circumstances, and prevents a pinhole and a crack generated in an aluminum foil, and a barrier material for a vacuum heat insulating material in which barrier properties are not easily lowered, and a heat insulating effect using the same. It aims at providing the vacuum heat insulating material which is hard to fall.

The invention according to claim 1 of the present invention is a vacuum heat insulating material used for a vacuum heat insulating material filled with a core material and deaerated inside, wherein an outer surface side protective film and an inner surface are formed on both surfaces of an aluminum foil. stacked and side protective film respectively, outer surface side protective film and the inner surface tensile modulus of the protective film is Ri 2.0~5.0GPa der, and
The outer surface side protective film is a polyethylene terephthalate film,
The inner surface side protective film is a polyamide film ,
The aluminum foil is an aluminum alloy foil containing 0.05% by weight or more and 0.3% by weight or less of silicon and 0.7% by weight or more and 1.7% by weight or less of iron .
It is the jacket material for vacuum heat insulating materials characterized by this.

  The jacket material for a vacuum heat insulating material of the present invention has the above-described configuration, and an outer surface side protective film and an inner surface side protective film having a tensile elastic modulus of 2.0 to 5.0 GPa on both surfaces of the aluminum foil, respectively. Since they are laminated, pinholes and cracks are prevented from occurring in the aluminum foil, and the barrier properties are unlikely to deteriorate.

The present invention uses a polyethylene terephthalate film for the outer surface side protective film of the vacuum heat insulating material, so it has high heat resistance compared to polypropylene film, etc., and damages to the aluminum foil at the time of bag making seal etc. Less is.

  In the present invention, since the inner surface side protective film of the jacket for vacuum heat insulating material is a polyamide film, it is more resistant to bending than polyethylene terephthalate film and polypropylene film, and the aluminum foil is bent at the corners and curved portions of the core material. Can be mitigated and pinholes and cracks generated can be prevented.

The invention according to claim 2 of the present invention is a vacuum heat insulating material characterized in that a core material is filled and accommodated with the outer covering material for vacuum heat insulating material according to claim 1 .

In the present invention, since the vacuum insulation material according to claim 1 is used for the vacuum insulation material, pinholes and cracks are hardly generated in the aluminum foil, and the barrier property is not easily lowered. As a material, the heat insulation effect is not easily lowered, and the durability is excellent.

  The jacket material for a vacuum heat insulating material of the present invention is less likely to cause pinholes and cracks in the aluminum foil, and the barrier property is unlikely to deteriorate. Moreover, the vacuum heat insulating material using it is hard to reduce the heat insulation effect, and is excellent in durability.

It is explanatory drawing which showed typically an example of the jacket material for vacuum heat insulating materials of this invention in the cross section. It is explanatory drawing which showed typically an example of the vacuum heat insulating material of this invention in the cross section.

Hereinafter, modes for carrying out the present invention will be described.
FIG. 1 is an explanatory view schematically showing a cross section of an example of a jacket material for a vacuum heat insulating material according to the present invention.

  As shown in FIG. 1, the outer cover material 10 for the vacuum heat insulating material of the present example has an outer layer film 1, an outer surface side protective film 2, an aluminum foil 3, an inner surface side protective film 4, and a heat welding layer from the outside of the vacuum heat insulating material 100. They are stacked in the order of 5. The outer surface side protective film 2 and the aluminum foil 3 are laminated with an adhesive between the aluminum foil 3 and the inner surface side protective film 4.

  As the adhesive, a urethane resin adhesive is preferably used. In particular, a urethane resin-based two-component curable adhesive is preferable, and the bonding method is preferably laminated by a dry lamination method. In particular, it is preferable to laminate a web-like material by a dry laminating method using a urethane resin two-component curable adhesive.

  The outer layer film 1 is a material for protecting the outer surface side protective film 2 from external wear, piercing, and the like, and is not particularly limited, but a stretched polyethylene terephthalate film, a stretched polypropylene film, a stretched nylon film, and the like 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 between the outer layer film 1 and the outer surface side protective film 2 may be bonded by a dry lamination method (including a solventless lamination method) or may be bonded by a sandwich lamination method.

  For the outer surface side protective film 2 and the inner surface side protective film 4, a film having a tensile modulus of 2.0 to 5.0 GPa measured according to JIS K7161-1994 is used. Examples of the film having a tensile modulus of 2.0 to 5.0 GPa include a stretched polyethylene terephthalate film, a stretched polypropylene film, a stretched nylon film, and a stretched ethylene vinyl alcohol copolymer film. Table 1 shows the measured tensile modulus of various films.

このように、外面側保護フィルム２及び内面側保護フィルム４の引張弾性率が２．０〜５．０ＧＰａのフィルムの間に、アルミニウム箔３を挟むことで、アルミニウム箔３に引っ張りや、突き刺しの影響が直接行かないようにしている。引張弾性率が２．０ＧＰａより小さいと、芯材の角や曲面部分で、アルミニウム箔３が引っ張られたりして、アルミニウム箔３にクラックや、ピンホールが発生してしまう。

Thus, the aluminum foil 3 is sandwiched between the outer surface side protective film 2 and the inner surface side protective film 4 having a tensile elastic modulus of 2.0 to 5.0 GPa, so that the aluminum foil 3 can be pulled or pierced. The influence is not made directly. If the tensile modulus is less than 2.0 GPa, the aluminum foil 3 is pulled at the corners or curved surfaces of the core material, and cracks and pinholes are generated in the aluminum foil 3.

  On the contrary, if the tensile modulus is greater than 5.0 GPa, the outer surface side protective film 2 and the inner surface side protective film 4 are bent acutely at the corners of the core material, and cracks and pinholes are generated in the aluminum foil 3. End up. Although the thickness of the outer surface side protective film 2 and the inner surface side protective film 4 is not particularly limited, it is preferably 6 μm to 50 μm.

  In particular, as the outer surface side protective film 2 and the inner surface side protective film 4, a stretched polyethylene terephthalate film or a stretched nylon film can be preferably used. Furthermore, a stretched nylon film is preferably used for the inner surface side protective film 4.

  The aluminum foil 3 is a main layer responsible for the barrier property of the vacuum insulating material 10 and if the aluminum foil 3 has pinholes or cracks, the quality as the vacuum heat insulating material 100 cannot be maintained.

Although not limited as the aluminum foil 3, it is preferable to use an aluminum alloy foil 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. . The aluminum alloy foil specified in this way is more resistant to bending than the 1N30 foil generally used for packaging, is less prone to pinholes and cracks, and is less likely to deteriorate barrier properties.

  Such an aluminum alloy foil is softer and more elongated than an aluminum foil of high purity, so that the aluminum foil itself is less likely to cause pinholes and cracks. As such aluminum alloy foil, there are aluminum alloy foils of alloy number A8021 and alloy number A8079.

  The thermal welding layer 5 is located in the innermost layer of the vacuum insulating material covering material 10 and seals the filled core material by thermal welding. As the heat welding layer 5, a thermoplastic resin is 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.

  The method for laminating the heat-welded layer 5 on the inner surface side protective film 4 is to bond the resin film by a dry lamination method (including a solvent-free lamination method) or by a sandwich lamination method. Also good. Further, the resin may be melted and bonded by an extrusion laminating method.

  FIG. 2 is an explanatory view schematically showing a cross section of an example of the vacuum heat insulating material of the present invention.

  Two of the vacuum insulating material covering materials 10 as described above are overlapped so that the heat-welded layer 5 faces each other, and the surroundings are heat-sealed except for the filling port filled with the core material 20. Then, the core material 20 is filled, the filling port is heat-sealed in a state where the inside is deaerated, and the vacuum heat insulating material 100 is formed as shown in FIG.

  Since the vacuum heat insulating material 100 uses the above-described vacuum heat insulating material covering material 10, pinholes and cracks are unlikely to occur in the aluminum foil 3, and the barrier property is unlikely to decrease, so the heat insulating effect is unlikely to decrease, Excellent durability.

  When the core material 20 is the vacuum heat insulating material 100, the core material 20 is not particularly limited as long as it can leave a decompressed space without being crushed even if it is pushed by the vacuum heat insulating material 10 by deaeration. It is not a thing.

  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.

  The vacuum heat insulating material 100 made by using the outer cover material 10 for vacuum heat insulating material is less likely to cause pinholes and cracks in the aluminum foil 3, and the barrier property is not easily lowered. Excellent in properties.

  Specific examples of the present invention will be described below.

<Example 1>
Stretched polypropylene film 20 μm as the outer layer film 1, stretched polyethylene terephthalate film 12 μm as the outer surface side protective film 2, aluminum alloy foil 7 μm of alloy number A8021 as the aluminum foil 3, stretched nylon film 15 μm as the inner surface side protective film 4, as the heat welding layer 5 Example 1 A linear low density polyethylene film of 50 μm was prepared, and each layer was sequentially laminated by a dry laminating method using a urethane resin-based two-component curable adhesive to form a laminate having the structure shown in FIG. The outer sheath material 10 for a vacuum heat insulating material was obtained.

<Example 2>
A vacuum heat insulating jacket material 10 of Example 2 was obtained in the same manner as in Example 1 except that the same stretched nylon film 15 μm as the inner surface side protective film 4 was used as the outer surface side protective film 2.

  Below, the comparative example of this invention is demonstrated.

<Comparative Example 1>
Stretched polyethylene terephthalate film 12 μm as outer layer film 1, stretched nylon film 15 μm as outer surface side protective film 2, aluminum alloy foil 7 μm of alloy number A8021 as aluminum foil 3, linear low density polyethylene 50 μm as heat welding layer 5, The inner surface side protective film 4 is not used, and the space between them is sequentially laminated by a dry laminating method using a urethane resin two-component curable adhesive, and a laminate is prepared. An outer jacket material was obtained.

<Comparative Example 2>
Stretched nylon film 15 μm as outer layer film 1, aluminum vapor-deposited stretched polyethylene terephthalate film 12 μm as outer surface side protective film 2, aluminum alloy foil 7 μm of alloy number A8021 as aluminum foil 3, and linear low density polyethylene 50 μm as heat welding layer 5 are prepared Then, without using the inner surface side protective film 4, the respective layers are sequentially laminated by a dry laminating method using a urethane resin two-component curable adhesive, and a laminated body is prepared. An outer jacket material was obtained.

<Test method>
The jacket materials for vacuum heat insulating materials of the example and the comparative example were tested by the following method and subjected to comparative evaluation.

<Gelboflex test>
Each of the jacket materials for vacuum heat insulating materials of the example and the comparative example was used as a test piece having a dimension of 205 mm × 290 mm, and three test pieces were prepared, and each of these test pieces was subjected to a gelbo flex test.

  Specifically, both short sides of the test piece are attached to the holding tool of the testing machine, and the test piece is shrunk by 3.5 inches while twisting the test piece so that the maximum twist angle is 440 ° in an environment of 5 ° C. The test piece was then further shrunk by 2.5 inches without being twisted, and then the cycle of returning the test piece to the initial state in the reverse stroke was repeated 300 times. Thereafter, the number of pinholes generated in the aluminum foil of the three test pieces was examined. The results of the investigation are summarized in Table 2 with the average number of pinholes of the three test pieces as the number of pinholes.

以下に、実施例と比較例との比較結果について説明する。

Below, the comparison result of an Example and a comparative example is demonstrated.

<Comparison result>
The outer sheath materials for vacuum heat insulating materials of Example 1 and Example 2 have a tensile modulus of 2.0 to 5.0 GPa on the outer surface side protective film 2 and the inner surface side protective film 4 on both sides of the aluminum foil 3, respectively. Since a film is used, a polyamide film or a polyethylene terephthalate film is used for the outer surface side protective film 2 and a polyamide film is used for the inner surface side protective film 4, aluminum is used even if the gelboflex test is performed. The number of pinholes generated in the foil 3 was very small.

  On the other hand, the envelope materials for vacuum heat insulating materials of Comparative Example 1 and Comparative Example 2 were prepared by using a polyamide film having a tensile modulus of 2.0 to 5.0 GPa or an aluminum vapor-deposited stretched polyethylene terephthalate film as the outer protective film 2. Although the inner surface side protective film 4 is not used, linear low density polyethylene having a tensile elastic modulus of less than 1 GPa of the heat-welded layer 5 is laminated directly on the aluminum foil 3 via an adhesive.

  In the comparative example 1 and the comparative example 2, in the gelboflex test, the number of pinholes generated in the aluminum foil 3 was 20 and 11, respectively. It can be seen that the number of pinholes is likely to occur in the aluminum foil 3.

  As described above, in the vacuum insulator jacket 10 according to the present invention, pinholes and cracks are unlikely to occur in the aluminum foil 3 which is the main layer responsible for barrier properties, and the barrier properties are unlikely to decrease. Therefore, the vacuum heat insulating material 100 of the present invention, in which the core material is filled and accommodated using this vacuum heat insulating jacket material 10 and deaerated and sealed, is due to the occurrence of pinholes and cracks in the aluminum foil 3. Deterioration of barrier properties hardly occurs, heat insulation effect does not decrease, and durability is excellent.

DESCRIPTION OF SYMBOLS 100 ... Vacuum heat insulating material 10 ... Cover material 20 for vacuum heat insulating materials ... Core material 1 ... Outer layer film 2 ... Outer surface side protective film 3 ... Aluminum foil 4 ... Inner surface side Protective film 5 ... heat welding layer

Claims (2)

An outer cover material for a vacuum heat insulating material used for a vacuum heat insulating material filled with a core material and deaerated inside, wherein an outer surface side protective film and an inner surface side protective film are respectively laminated on both surfaces of the aluminum foil, and the outer surface side protective film and the inner surface tensile modulus of the protective film is Ri 2.0~5.0GPa der, and
The outer surface side protective film is a polyethylene terephthalate film,
The inner surface side protective film is a polyamide film ,
The aluminum foil is an aluminum alloy foil containing 0.05% by weight or more and 0.3% by weight or less of silicon and 0.7% by weight or more and 1.7% by weight or less of iron .
An outer covering material for a vacuum heat insulating material. A vacuum heat insulating material, wherein the core material is filled and accommodated with the envelope material for a vacuum heat insulating material according to claim 1 .

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