JP2020142401A - Heat insulation sheet and heat insulation box - Google Patents

Abstract

To improve an appearance of a heat insulation sheet.SOLUTION: A heat insulation sheet 10 includes: a foam sheet 12; a front material 14 arranged on one surface of the foam sheet 12 in an overlapping manner, and constituting the front surface of the heat insulation sheet 10; and a rear material 16 arranged on the other surface opposite to the one surface of the foam sheet 12 in an overlapping manner, and constituting the rear surface of the heat insulation sheet 10. The front material 14 includes: a surface layer film 22 at least having a layer made of polyester resin, and constituting the front surface of the heat insulation sheet 10; and an intermediate layer film 24 composed of low-density polyethylene, and arranged between the surface layer film 22 and the foam sheet 12.SELECTED DRAWING: Figure 1

Description

The present invention relates to a heat insulating sheet that prevents heat from passing through and a heat insulating box that uses the heat insulating sheet.

As a heat insulating container used for transporting frozen foods and fresh foods, there is a heat insulating container whose opening is closed by a heat insulating cover (see, for example, Patent Document 1). The heat insulating cover is formed by arranging a pair of heat insulating sheets on both sides, locating a foam layer in an intermediate layer, and suturing them facing each other. The heat insulating sheet is obtained by adhering a non-woven fabric layer adhered to an aluminum vapor-deposited film to a foam layer, and has a laminated structure in which the non-woven fabric layer is sandwiched between the aluminum-deposited film and the foam layer.

Jikken Sho 62-17235

When the above-mentioned heat insulating sheet is exposed to a high temperature, the surface may be wrinkled and the appearance may be deteriorated.

The present invention has been proposed in view of the above-mentioned problems related to the prior art, and an object of the present invention is to provide a heat insulating sheet having a good appearance and a heat insulating box using the heat insulating sheet. To do.

In order to overcome the above-mentioned problems and achieve the desired object, the heat insulating sheet according to the present invention is used.
Foam sheet and
An outer material arranged on one surface of the foam sheet and
It is provided with a lining which is arranged so as to be overlapped on the other surface on the opposite side of the foam sheet and constitutes the back surface of the heat insulating sheet.
The outer material is
A surface film having at least a layer made of polyester resin and constituting the surface of the heat insulating sheet,
A middle layer film composed of low density polyethylene and arranged between the surface film and the foam sheet.
The gist is that the lining has at least a cloth composed of olefin resin fibers.

In order to overcome the above-mentioned problems and achieve the intended purpose, the heat insulating box according to the present invention is used.
It is a gist that the wall surface is formed by the heat insulating sheet according to the present invention.

According to the heat insulating sheet according to the present invention, deformation such as wrinkles is unlikely to occur, and the appearance is good.
According to the heat insulating box according to the present invention, the wall surface is less likely to be deformed such as wrinkles and has a good appearance.

It is a perspective view which shows the main part of the heat insulating sheet which concerns on a preferred embodiment of this invention by partially breaking. It is sectional drawing of the heat insulating sheet of an Example. It is an enlarged view of the part A of FIG. It is a perspective view which shows an example of the heat insulation box using the heat insulation sheet of an Example. It is sectional drawing which shows by breaking a part of the wall part of the heat insulation box which concerns on Example. It is explanatory drawing which shows the manufacturing process of the outer material of an Example. It is explanatory drawing which shows the manufacturing process of the heat insulating sheet of an Example. It is explanatory drawing which shows the manufacturing process of the heat insulating sheet of an Example. It is explanatory drawing which shows the test apparatus of a heat-shielding property.

Next, a heat insulating sheet according to the present invention and a heat insulating box using the heat insulating sheet will be described below with reference to the accompanying drawings with reference to suitable examples.

As shown in FIGS. 1 and 2, the heat insulating sheet 10 according to the embodiment includes a foam sheet 12, an outer material 14 arranged so as to overlap one surface side of the foam sheet 12, and one surface side of the foam sheet 12. It is a sheet-like laminated body having a lining 16 arranged so as to overlap the other surface side on the opposite side. In the heat insulating sheet 10, the outer material 14 and the lining 16 are arranged so as to sandwich the foam sheet 12, the front surface of the heat insulating sheet 10 is made of the outer material 14, and the back surface of the heat insulating sheet 10 is made of the lining 16. The heat insulating sheet 10 has deformable flexibility such as bending in the plate thickness direction or being rolled into a roll shape, cushioning property that can be compressed in the plate thickness direction, and when compressed in the plate thickness direction. It has the elasticity to return to its original state. Here, the front side of the heat insulating sheet 10 refers to the side that is exposed to the outside air or is exposed to sunlight, and when the heat insulating box 30 described later is configured, the side facing the outside of the heat insulating box 30 is used. Become. Further, the back side of the heat insulating sheet 10 is the inside facing the storage space 30a side of the heat insulating box 30 when the heat insulating box 30 described later is constructed.

As shown in FIGS. 1 and 2, in the heat insulating sheet 10, the outer material 14 and the lining 16 are bonded to the foam sheet 12 via extruded films 18 and 20 made of an olefin resin. Specifically, as shown in FIG. 2, the foam sheet 12 and the outer material 14 are joined by the front side extruded film 18, and the foam sheet 12 and the lining 16 are joined by the back side extruded film 20. The extruded films 18 and 20 are solidified from a molten state between the foam sheet 12 and the outer material 14 (lining 16) to form a film, and adhere to the foam sheet 12 and the outer material 14 (lining 16). There is.

The foam sheet 12 is composed of a foam such as a polypropylene-based foam, a polyethylene-based foam, or a polyurethane-based foam. As the foam sheet 12, it is preferable to use a polypropylene-based foam or a cross-linked polyethylene-based foam having excellent heat resistance, and a polypropylene-based foam is particularly preferable. As the foam sheet 12, for example, a polypropylene-based foam having a closed cell structure obtained by a supercritical method can be used in the form of a sheet. Since the foam sheet 12 by such a supercritical method has fine bubbles independent of each other, low thermal conductivity can be achieved, which is preferable from the viewpoint of heat insulating properties. The cross-linked polyethylene-based foam can be used without limitation as long as it is in the form of a sheet obtained through a cross-linking step using polyethylene containing α-olefin as a raw material. The method of cross-linking the polyethylene resin includes a method of irradiating ionizing radiation to cross-link, a method of adding an organic peroxide and then heating to cross-link, and water having a silyl group (silane) that cross-links in contact with water. After foaming the cross-linked polyethylene resin, there is a method of bringing the foam into contact with water for cross-linking. It should be noted that the polypropylene-based foam or the cross-linked polyethylene-based foam is excellent in heat resistance because at least the extruded film made of the olefin resin described later is melted and acts as an adhesive, but the foam must not be deformed or deteriorated. There is.

The foam sheet 12 has a thin plate shape having a thickness of, for example, 0.1 mm to 1.8 mm, preferably 0.9 mm to 1.8 mm, and the cell diameter is in a range smaller than the thickness of the foam sheet 12. For example, a fine one having a diameter of 10 μm to 350 μm is preferable. The foam sheet 12 has a density based on JIS K7112 ^is preferably in the range of ^{40kg / m 3 ~750kg / m 3} , more preferably in the range of ^{40kg / m 3 ~85kg / m 3} . The foam sheet 12 preferably has a vertical tensile strength (TD) based on JIS K6767 in the range of 0.2 MPa to 12 MPa, more preferably in the range of 0.2 MPa to 1.1 MPa. Further, the foam sheet 12 preferably has a tensile strength (MD) in the flow direction based on JIS K6767 in the range of 0.5 MPa to 18 MPa, more preferably in the range of 0.5 MPa to 1.8 MPa. ..

The foam sheet 12 preferably has a compressive stress in the range of 0.005 MPa to 0.013 MPa when the strain is 10% measured in accordance with JIS K6767. The foam sheet 12 preferably has a compressive stress in the range of 0.007 MPa to 0.2 MPa when the strain is 25% measured in accordance with JIS K6767, and more preferably 0.007 MPa to 0.021 MPa. Is the range of. The foam sheet 12 preferably has a compressive stress in the range of 0.013 MPa to 1.0 MPa when the strain is 55% measured in accordance with JIS K6767, and more preferably 0.013 MPa to 0.04 MPa. Is the range of.

As shown in FIG. 3, the outer material 14 is a middle layer that is laminated on the back side of the surface film 22 that constitutes the surface of the heat insulating sheet 10 and the surface film 22 and is arranged between the surface film 22 and the foam sheet 12. It includes a film 24. The outer material 14 is a layer that is exposed to the outside of the heat insulating sheet 10 and constitutes a surface that serves as a design surface. The surface film 22 has at least a layer made of a polyester resin, and is relatively excellent in heat resistance and mechanical strength such as tear strength. In the embodiment, a metallized film 22b obtained by depositing a metal such as aluminum is laminated on a film-like base material (layer made of polyester resin) 22a made of a thermoplastic resin such as polyethylene terephthalate (PET). Metallized film is used. Aluminum is preferable as the metal constituting the metal vapor deposition film 22b. As the surface film 22, for example, a film having a thickness in the range of 10 μm to 50 μm, preferably in the range of 11 μm to 18 μm may be used. The surface layer film 22 preferably has a flow direction tensile strength (MD, machine direction) based on JIS C2318 in the range of 2 MPa to 240 MPa, and a vertical tensile strength (TD, traverse direction) based on JIS C2318 of 2 MPa to 240 MPa. It is preferably in the range of 230 MPa. Further, the surface layer film 22 preferably has a lamination strength of the metal vapor deposition film 22b with respect to the base material 22a of 200 g / 15 mm or more. The surface layer film 22 may be composed of only the base material 22a which does not have the metal vapor deposition film 22b, but by using the metal vapor deposition film as the surface layer film 22 as in the embodiment, the surface layer film 22 is excellent in light shielding. It is preferable to have the metal-deposited film 22b because the heat-shielding property of the heat insulating sheet 10 can be improved depending on the property.

As the middle layer film 24, a film made of low density polyethylene is used. Low-density polyethylene is a polymer material having a low-density 0.91 g / cm ^{3 to} 0.93 g / cm ³ ethylene as a repeating unit. Among the low-density polyethylenes, the middle-layer film 24 is preferably made of Linear Low Density Polyethylene (LLDPE), which has a good balance between rigidity and flexibility and is resistant to stress cracking. As the middle layer film 24, for example, a film having a thickness in the range of 40 μm to 100 μm, preferably in the range of 50 μm to 70 μm may be used. The intermediate layer film 24 preferably has a flow direction tensile strength (MD, machine direction) based on JIS C2318 in the range of 2 MPa to 240 MPa, and a vertical tensile strength (TD, traverse direction) based on JIS C2318 of 2 MPa to 240 MPa. It is preferably in the range of 230 MPa. In the outer material 14, the surface layer film 22 and the middle layer film 24 are joined and integrated by, for example, a dry laminating method via an adhesive.

As shown in FIGS. 1 and 2, the lining 16 has at least a cloth 26 composed of olefin resin fibers, and is a layer for ensuring the strength of the heat insulating sheet 10. In the lining 16 of the embodiment, the protective film 28 is arranged on the back side of the cloth 26, and the protective film 28 constitutes the back surface of the heat insulating sheet 10 in the lining 16. The cloth 26 may be a net or a knitted woven fabric. Specifically, it is a fabric constructed by weaving olefin resin fibers such as polyethylene. The fiber is not particularly limited, and flat yarn, multifilament, monofilament, staple fiber and the like can be used. Among them, a polyethylene woven fabric made of flat yarn of 10 × 10 (10 × 10/1 inch) per inch and 1000 dtex is preferable in consideration of strength and sewability. The cloth 26 preferably has a longitudinal tensile strength in the range of 450 N / 25 mm to 670 N / 25 mm, and a lateral tensile strength in the range of 390 N / 25 mm to 710 N / 25 mm. Further, the cloth 26 preferably has an elongation in the vertical direction in the range of 17% to 33%, and a tensile strength in the horizontal direction preferably in the range of 11% to 25%. The tensile strength and elongation of the cloth 26 are measured at a sample width of 5 cm, a grip interval of 20 cm, and a tensile speed of 20 cm / min in accordance with the JIS L1096 A method (cut strip method).

The protective film 28 is provided to protect the outer surface of the cloth 26 and prevent the fibers constituting the cloth 26 from fraying, and the protective film 28 may be omitted in the lining 16. As the synthetic resin constituting the protective film 28, for example, polyethylene or a copolymer containing polyethylene can be used. Examples of polyethylene include low-density polyethylene. Examples of the copolymer resin containing polyethylene include an ethylene-methyl methacrylate copolymer resin and a polyethylene-ethylene polymer-maleic anhydride copolymer resin. The thickness of the protective film 28 is preferably set in the range of, for example, 10 μm to 50 μm.

The extruded films 18 and 20 are made of an olefin resin. As the synthetic resin constituting the extruded films 18 and 20, for example, polyethylene or a copolymer containing polyethylene can be used. Examples of polyethylene include low-density polyethylene. Examples of the copolymer resin containing polyethylene include an ethylene-methyl methacrylate copolymer resin and a polyethylene-ethylene polymer-maleic anhydride copolymer resin. As the ethylene-based polymer of the copolymer resin, an ethylene-methyl methacrylate copolymer resin is preferable. By using the ethylene-methylmethacrylate copolymer resin as the front side extruded film 18, the middle layer film 24 made of low-density polyethylene and the foam sheet 12 made of polypropylene-based foam or cross-linked polyethylene-based foam can be firmly formed on the outer material 14. Can be glued. Similarly, by using the ethylene-methylmethacrylate copolymer resin as the back side extruded film 20, the cloth 26 woven with olefin resin fibers in the lining 16 and the foam sheet 12 can be firmly adhered to each other.

The front side extruded film 18 for joining the outer material 14 is preferably formed thicker than the back side extruded film 20 for joining the lining material 16. The back side extruded film 20 is preferably set in the range of, for example, 10 μm to 50 μm. On the other hand, the front side extruded film 18 is preferably set in the range of, for example, 20 μm to 100 μm, more preferably in the range of 30 μm to 100 μm, and further preferably in the range of 50 μm to 100 μm. When the front side extruded film 18 is within the thickness range, the unevenness of the cloth 26 of the lining 16 can be prevented from appearing on the surface of the outer material 14, and the heat generated when the front side extruded film 18 is formed has an adverse effect on the outer material 14. It can be avoided.

As shown in FIG. 4, the heat insulating box 30 can be constructed by using the heat insulating sheet 10 described above. The heat insulating box 30 of the embodiment is composed of six surfaces by a wall portion 32 having heat insulating properties. The heat insulating box 30 is formed in a box shape by directly or indirectly connecting adjacent wall portions 32, 32 by sewing. The heat insulating box 30 opens and closes the upper wall portion 32 so that articles can be taken in and out of the storage space 30a defined inside, and the front wall portion 32 can also be opened and closed. As shown in FIG. 5, the wall portion 32 is formed by superimposing the two heat insulating sheets 10 and 10 described above and sewing them in a bag shape, and if necessary, plastic between the heat insulating sheets 10 and 10. An intermediate member 34 such as a reinforcing plate such as corrugated cardboard and a heat insulating plate such as slab urethane is arranged. In the wall portion 32 whose wall surface is composed of the heat insulating sheet 10 described above, each heat insulating sheet is provided so that the surface film 22 (metal vapor deposition film 22b) of the outer material 14 becomes the surface (design surface) of the wall portion 32. While the 10 is arranged, the lining 16 of each heat insulating sheet 10 is arranged inside the wall portion 32. The wall portion 32 may be reinforced with a reinforcing material such as a belt woven with a sheet at the edge of the heat insulating sheet 10.

Next, the method for manufacturing the heat insulating sheet 10 described above will be described below with reference to FIGS. 6 to 8. In the examples, the outer material 14 obtained by joining the surface film 22 and the middle layer film 24 is manufactured by a dry laminating method. Further, in the production of the heat insulating sheet 10 obtained by joining the foam sheet 12, the outer material 14 and the lining 16, a sandwich laminating method is used among the methods called extrusion laminating.

First, the foam sheet 12, the outer material 14, and the lining 16 are prepared, respectively. As shown in FIG. 6, the middle layer film 24 is pulled out from the film roll 40 around which the middle layer film 24 is wound, and the adhesive coating portion 42 applies an adhesive to one surface of the middle layer film 24. After the adhesive is dried in the dryer 44, the surface layer film 22 drawn from the film roll 46 around which the surface layer film 22 is wound is attached to one surface of the middle layer film 24. The outer material 14 obtained by laminating the surface layer film 22 and the middle layer film 24 by the dry laminating method in this way is wound around a roll and recovered.

As shown in FIG. 7, the outer material 14 is pulled out from the film roll 48 around which the outer material 14 is wound, and the foam sheet 12 is pulled out from the sheet roll 50 around which the foam sheet 12 is wound. The molten olefin resin 52 is extruded into one of the outer material 14 and the foam sheet 12 (outer material 14 in the embodiment) by the extruder 54 via the T-die 56. Further, the outer material 14 and the other side of the foam sheet 12 (foam sheet 12 in the example) are superposed on the extruded olefin resin 52. Next, the laminate in which the olefin resin 52 is poured between the outer material 14 and the foam sheet 12 is passed through a cooling roll 58 to cool and solidify the olefin resin 52, whereby the outer material 14 and the foam sheet 12 are solidified. Is joined with the front side extruded film 18 to obtain a laminated body 60. Then, the laminated body 60 is wound around a roll and collected.

The lining 16 can be obtained by using a single laminating method among a methods called extrusion laminating. The molten olefin resin is extruded through a T-die by an extruder onto one surface of the cloth 26 drawn from the film roll around which the cloth 26 is wound. Next, the olefin resin is cooled and solidified by passing it through a cooling roll to obtain a lining 16 in which the protective film 28 is laminated on one surface of the cloth 26. Then, the lining 16 is wrapped around a roll and collected.

As shown in FIG. 8, the lining 16 is pulled out from the lining roll 62 around which the lining 16 is wound, and the laminate 60 is pulled out from the laminate roll 64 around which the laminate 60 is wound. The molten olefin resin 52 is extruded into one of the lining 16 and the laminate 60 (lining 16 in the embodiment) by the extruder 54 via the T-die 56. Further, the lining 16 and the other side of the laminated body 60 (laminated body 60 in the embodiment) are superposed on the extruded olefin resin 52. Next, the laminate in which the olefin resin 52 is poured between the lining 16 and the laminate 60 is passed through a cooling roll 58 to cool and solidify the olefin resin 52, whereby the lining 16 and the laminate 60 are backed. The heat insulating sheet 10 is obtained by joining with the extruded film 20 and sandwiching the foam sheet 12 between the outer material 14 and the lining material 16. Then, the heat insulating sheet 10 is wrapped around a roll and collected.

In the extrusion lamination, the olefin resin 52 for laminating the foam sheet 12 and the outer material 14 is applied so as to be thicker than the olefin resin 52 for laminating the foam sheet 12 and the lining 16. As a result, the front side extruded film 18 arranged between the foam sheet 12 and the outer material 14 is formed thicker than the back side extruded film 20 arranged between the foam sheet 12 and the lining material 16.

By using the foam sheet 12 made of polypropylene-based foam or cross-linked polyethylene-based foam, which is superior in heat resistance to the polyethylene foam, the heat-insulating sheet 10 described above is used even when placed in a high-temperature environment. , Deformation such as shrinkage or expansion of the foam sheet 12 is unlikely to occur. Therefore, the heat insulating sheet 10 can prevent surface defects such as wrinkles on the outer material 14 due to the deformation of the foam sheet 12, is resistant to environmental changes, and can maintain its appearance. Moreover, since the foam sheet 12 is arranged between the lining 16 and the outer material 14 of the heat insulating sheet 10, the texture of the cloth 26 constituting the lining 16 appears on the outer material 14 (the surface of the heat insulating sheet 10). Can be prevented.

The heat insulating sheet 10 is superposed on the back side of the surface film 22 forming the surface of the heat insulating sheet 10 on the outer material 14, and the middle layer film 24 is arranged. Due to the presence of the intermediate layer film 24, the heat insulating sheet 10 can be prevented from being deformed such as shrinkage or expansion of the outer material 14 even when it is placed in a high temperature environment. Therefore, the heat insulating sheet 10 can prevent surface defects such as wrinkles on the outer material 14, is resistant to environmental changes, and can maintain its appearance.

In the heat insulating sheet 10, the outer material 14 and the lining 16 are bonded to the foam sheet 12 via the extruded films 18 and 20 made of an olefin resin, so that the extruded films 18 and 20 heat the heat insulating sheet 10 in the thickness direction. Conduction can be prevented and thermal resistance can be improved. In this way, even in a relatively thin laminate composed of the outer material 14, the foam sheet 12, and the lining 16, the presence of the extruded films 18 and 20 lowers the thermal conductivity of the heat insulating sheet 10 (increases the thermal resistance). And the layer structure can be minimized. Further, the presence of the front side extruded film 18 makes it possible to set the thickness of the middle layer film 24 of the outer material 14 to be thin, and the heat insulating sheet 10 can be made relatively thin while having excellent heat insulating properties.

Of the extruded films 18 and 20, the heat insulating sheet 10 is formed so that the front side extruded film 18 for joining the outer material 14 constituting the surface of the heat insulating sheet 10 is thicker than the back side extruded film 20 for joining the lining 16. As described above, the front side extruded film 18 formed to be relatively thick between the outer material 14 and the foam sheet 12 can prevent the texture of the cloth 26 of the lining 16 from appearing on the outer material 14. Moreover, by forming the extruded films 18 and 20 with the ethylene-methyl methacrylate copolymer resin, the extruded films 18 and 20 can prevent peeling of each layer. The copolymer is particularly compatible with the foam sheet 12 made of polypropylene-based foam or cross-linked polyethylene-based foam and the middle-layer film 24 made of low-density polyethylene.

Since the wall surface of the heat insulating box 30 described above is formed by the heat insulating sheet 10 described above, wrinkles are unlikely to occur on the wall surface even due to a temperature change such as at a high temperature, and the texture of the cloth 26 of the lining 16 does not appear. It looks good.

According to the method for manufacturing the heat insulating sheet 10 described above, the heat insulating sheet 10 laminated by sandwiching the foam sheet 12 between the outer material 14 and the lining 16 can be easily obtained. Since the foam sheet 12 is arranged between the lining 16 and the outer material 14, it is possible to prevent the texture of the cloth 26 of the lining 16 from being transferred to the outer material 14 when the layers are overlapped and pressed. The resulting heat insulating sheet 10 has a good appearance.

By using a foam sheet 12 made of polypropylene-based foam or cross-linked polyethylene-based foam, which has excellent heat resistance as compared with non-crosslinked polyethylene foam, an olefin resin that melts and has a high temperature is compared with the foam sheet 12. It can be given as many as possible. In the manufacturing method described above, since the foam sheet 12 has elasticity, when the layers are pressed to be laminated, the unevenness of the texture of the cloth 26 becomes the surface opposite to the lining 16 in the foam sheet 12. May appear. As described above, since the front side extrusion film 18 can be controlled to be relatively thick, even if the front side extrusion film 18 is made thick and the unevenness of the cloth 26 is transferred to the foam sheet 12, the front side extrusion film 18 is extruded. The film 18 can prevent the unevenness from appearing on the outer material 14. Further, since the outer material 14 is composed of two layers of the surface layer film 22 and the middle layer film 24, heat is transferred to the surface layer film 22 due to the presence of the middle layer film 24 when the outer material 14 and the foam sheet 12 are laminated. It can be made difficult, and deterioration of appearance such as wrinkles on the surface film 22 at the time of laminating can be prevented.

(Test 1)
A heat insulating sheet according to a test example based on the above-mentioned example was prepared, and strength (tensile strength, elongation, tear strength, piercing strength), weight, sensory evaluation (appearance, crease stability, soft feeling), heat resistance. I investigated each of them. As the heat insulating sheets of Examples 1 to 7 and the heat insulating sheets of Comparative Examples 1 and 2, the heat insulating sheets shown below are used for each layer, and the heat insulating sheets are obtained by the extrusion lamination described above. The thickness of each layer is as shown in Tables 1 and 2.
-Surface film (Examples 1 to 6 and Comparative Example 2)
AL / PET: Aluminum vapor-deposited film with aluminum vapor-deposited on a film made of polyethylene terephthalate, thickness 12 μm (trade name: VMPET, manufactured by Toray Film Processing Co., Ltd.)
-Surface film (Example 7)
PET: Film, transparent film consisting only of polyethylene terephthalate without metal deposition, thickness 12 μm
-Medium-layer film (Examples 1 to 7 and Comparative Example 1)
LLDPE: A film made of linear polyethylene (linear low density polyethylene). It is laminated on the surface film by the dry laminating method.
-Foam sheet (Examples 1 to 7 and Comparative Example 2)
PP: Polypropylene foam, thickness 0.9 mm (trade name: FOLEC LZ2000S, manufactured by Inoac Corporation)
-Foam sheet (Comparative Example 1)
PE: Polyethylene foam, thickness 1.0 mm (Product name: Mirror mat, manufactured by JPS Co., Ltd.)
-Cross (Examples 1 to 7 and Comparative Examples 1 to 2)
PE: Polyethylene cloth 10 x 10, thickness 0.25 mm (manufactured by Hagiwara Industries, Ltd.)
-Protective film (Examples 1 to 7 and Comparative Examples 1 to 2)
LDPE: A film made of low density polyethylene. It is laminated on the cloth by the extrusion laminating method.
Extruded film (Examples 1 to 7 and Comparative Example 2)
Copolymerized PE: Ethylene-methylmethacrylate copolymer resin (trade name: Aklift, manufactured by Sumitomo Chemical Co., Ltd.)
-Extruded film (Comparative Example 1)
LDPE: Low density polyethylene

(Strength)
-Tensile strength and elongation are average values measured three times at a distance between chucks of 40 mm in each of the vertical and horizontal directions in accordance with JIS L6767 Annex 12. Here, "vertical" in Table 1 refers to the flow direction (MD, machine direction) of the foam sheet, and "horizontal" refers to the vertical direction (TD, traverse direction) of the foam sheet.
-The tear strength is an average value measured three times at a distance between chucks of 40 mm in each of the vertical direction and the horizontal direction in accordance with JIS L6767 8.7.
-For piercing strength, prepare a square test piece with a side of 150 mm, and clamp the test piece with a ring-shaped jig with an inner diameter of 102 mm. A needle having a tip shape of R0.5 mm was pierced into the test piece at 500 mm / min, and the maximum load until the test piece was pierced was measured.
The results of tensile strength, elongation, tear strength and piercing strength are shown in Table 1. The comparison in Table 1 is a comparison with Comparative Example 1 (Example / Comparative Example 1), and the case where the strength is higher than that of Comparative Example 1 is evaluated as “〇”, and the case where the strength is lower than that of Comparative Example 1 is evaluated. Evaluate as "x".

As shown in Tables 1 and 2, the heat insulating sheets of Examples 1 to 6 and Comparative Example 2 using the polypropylene-based foam as the foam sheet are the heat insulating sheets of Comparative Example 1 using the polyethylene foam as the foam sheet. It can be confirmed that all of the tensile strength, elongation, tear strength and piercing strength are improved as compared with the sheet. As described above, it can be seen that the heat insulating sheet using the foam sheet made of polypropylene-based foam has excellent mechanical strength.

(Test 2)
The weight, sensory evaluation (appearance, crease restoration property, soft feeling), and heat resistance of the heat insulating sheets of Examples 1 to 7 and the heat insulating sheets of Comparative Examples 1 and 2 described above were examined. The thickness of each layer is as shown in Tables 3 and 4.

(weight)
The weights shown in Tables 3 and 4 are the results of measuring the weights of the heat insulating sheets of Examples and Comparative Examples. The thickness of the heat insulating sheet is indicated by the basis weight (g / m ² ) and is indicated by the weight of a 1 m square (100 cm in length and width). The comparison of the weights shown in Tables 3 and 4 is a comparison with Comparative Example 1 (Example (Comparative Example 2) / Comparative Example 1), and a case lighter than Comparative Example 1 is evaluated as “◯”. Further, when it is heavier than Comparative Example 1 and the difference is smaller than 10 g, it is evaluated as “Δ”, and when it is heavier than Comparative Example 1 and the difference is 10 g or more, it is evaluated as “×”. The results are shown in Tables 3 and 4.

(sensory evaluation)
The appearances shown in Tables 3 and 4 are marked with "○" when wrinkles cannot be confirmed when the surface (outer material side) of the heat insulating sheet is visually observed, and "△" when there are fewer wrinkles than in Comparative Example 1. The case where there were more wrinkles than in Comparative Example 1 was evaluated as “x”.
The crease restoration property shown in Table 2 is when the heat insulating sheet is bent under the same conditions and then returned to the original unfolded state. At this time, when the surface (outer material side) of the heat insulating sheet is visually observed, wrinkles cannot be confirmed. Was evaluated as “◯”, the case where there were fewer wrinkles than in Comparative Example 1 was evaluated as “Δ”, and the case where there were more wrinkles than in Comparative Example 1 was evaluated as “×”.
The soft feeling shown in Table 2 is "○" when the heat insulating sheet is pressed from the surface (outer material side) under the same conditions as softer than Comparative Example 1, and "x" when it is harder than Comparative Example 1. I evaluated it.
The results of the sensory evaluation are shown in Tables 3 and 4.

(Heat-resistant)
The heat resistance shown in Tables 3 and 4 has less wrinkles than Comparative Example 1 when the heat insulating sheet was left in an environment of 70 ° C. for 1 hour and then the surface (outer material side) of the heat insulating sheet was visually observed. The case was evaluated as “◯”, and the case with more wrinkles than in Comparative Example 1 was evaluated as “x”. The results are shown in Tables 3 and 4.

(Comprehensive evaluation)
In the comprehensive evaluation, the case where the heat resistance is "○" and all the sensory evaluations are "○" is "◎", and the case where the heat resistance is "○" and any one of the sensory evaluations is "△" is "△". When the heat resistance is "○" and two or more sensory evaluations are "Δ" or even one sensory evaluation has "x", it is evaluated as "Δ". Then, the case where the heat resistance is "x" is evaluated as "x".

As shown in Tables 3 and 4, Examples 1 to 6 using a foam sheet made of polypropylene-based foam have an appearance, crease resilience, and a soft feeling as compared with Comparative Example 1 using polyethylene foam. You can see that it is improving. Moreover, it can be confirmed that the heat insulating sheets of Examples 1 to 6 are superior in heat resistance to that of Comparative Example 1. As described above, according to the heat insulating sheets of Examples 1 to 6, not only the appearance, the crease restoration property and the soft feeling are excellent, but also the heat resistance is high, so that the appearance can be improved even in a high temperature environment, for example. Can be kept. As shown in Table 3, by setting the thickness of the front side extruded film in the range of 25 μm to 45 μm, both the sensory evaluation and the heat resistance can be achieved. Further, as shown in Table 3, the sensory evaluation is improved by making the thickness of the front side extruded film thicker than that of the back side extruded film. Further, as shown in Table 3, even if the middle layer film is thinner than 100 μm, both the sensory evaluation and the heat resistance can be achieved.

(Test 3)
Regarding the heat insulating sheet of Example 3 described above, the heat insulating sheet of Example 7 prepared with the configuration shown in Table 3, and the heat insulating sheets of Comparative Examples 3 to 5 shown below, the heat shielding property, the thermal conductivity, and the heat retaining property were confirmed respectively. did. The heat insulating sheet of Example 7 is different from Example 3 in that a PET film having no metal vapor deposition film is used as the surface film and the middle layer film is 40 μm.

The heat insulating sheet of Comparative Example 3 is a film made of transparent polyethylene terephthalate having a thickness of 12 μm, a polyethylene film having a thickness of 25 μm, a polyethylene film having a thickness of 20 to 25 μm, and a white polyethylene having a thickness of 40 μm, in this order from the front side to the back side. It is composed of an ultraviolet protection film made of, an ultraviolet protection cloth made of 12 × 12 filaments per inch square, and an ultraviolet protection film made of silver polyethylene having a thickness of 40 μm. The thickness of the cloth is displayed by the driving density, for example, 12 × 12 lines / 1 inch.
In Comparative Example 4, an aluminum vapor-deposited film (thickness 12 μm, trade name: VMPET, manufactured by Toray Film Processing Co., Ltd.) in which aluminum is vapor-deposited on a film made of polyethylene terephthalate is used as the outer material, and the lining is formed with the aluminum-deposited film. A cloth made of polyethylene fibers (10 x 10 pieces / 1 inch) is bonded with a film (thickness 100 μm) made of LLDPE (linear polyethylene (linear low density polyethylene)).
The heat insulating sheet of Comparative Example 5 is, in order from the front side to the back side, an ultraviolet protection film made of silver polyethylene having a thickness of 40 μm, a 10 × 10/1 inch ultraviolet protection cloth, and an ultraviolet protection sheet made of silver polyethylene having a thickness of 40 μm. It is composed of laminated films.

As shown in FIG. 9, the heat-shielding property shown in Table 5 is such that four heat insulating sheets are arranged side by side on the lower side of the ref lamp and the upper surface of the black sheet arranged under the heat insulating sheet is arranged. A temperature sensor was installed to correspond to each heat insulating sheet. Light was irradiated from a ref lamp (100 W) installed 200 mm above the heat insulating sheet toward the heat insulating sheet for 15 minutes, and the temperature change was measured with a temperature sensor. As a result of the temperature measurement, the case where the maximum temperature was 30 ° C. or lower was evaluated as "◯", and the case where the maximum temperature exceeded 30 ° C. was evaluated as "x".
The thermal conductivity shown in Table 5 was measured using a measuring device (QTM-500 manufactured by Kyoto Denshi Kogyo Co., Ltd.) in accordance with the hot wire method JIS R2616. The case where the thermal conductivity was 0.2 W / M · K or less was evaluated as “◯”, and the case where the thermal conductivity exceeded 0.2 W / M · K was evaluated as “x”.
The heat retention shown in Table 5 is measured based on the Thermolab II dry contact method (Boken Quality Evaluation Organization), and when the heat retention is 16% or more, it is evaluated as "○" and the heat retention is 16%. If it was smaller, it was evaluated as "x".
Table 5 shows the results of heat insulation, thermal conductivity and heat retention.

As shown in Table 5, the heat insulating sheets of Examples 3 and 7 are excellent in all of heat shielding property, thermal conductivity and heat retention property, and it can be confirmed that they are suitable as heat insulating sheets.

(Change example)
The example is not limited to the above-described embodiment, and may be changed as follows, for example.
(1) The heat insulating sheet is not limited to the layer structure of the embodiment, and a layer that exhibits a function as required may be provided.
(2) The heat insulating box may have a structure in which the heat insulating box can be kept in a box shape by itself, or may be in a box shape by being attached to a trolley or the like. Further, by utilizing the flexibility of the heat insulating sheet, it can be folded from a box shape into a compact structure.
(3) A single laminating machine is connected to the sandwich laminating machine shown in FIG. 6, and one of the outer material and the lining and the foam sheet are laminated to form a laminated body, and then the laminated body, the outer material and the lining are continuously formed. It can also be laminated with the other.

10 Insulation sheet, 12 Foam sheet, 14 Outer material, 16 Lining,
18 Front side extruded film (extruded film), 20 Back side extruded film (extruded film),
22 surface film, 24 middle layer film, 26 cloth

Claims (5)

Foam sheet and
An outer material arranged on one surface of the foam sheet and
It is provided with a lining which is arranged so as to be overlapped on the other surface on the opposite side of the foam sheet and constitutes the back surface of the heat insulating sheet.
The outer material is
A surface film having at least a layer made of polyester resin and constituting the surface of the heat insulating sheet,
A middle layer film composed of low density polyethylene and arranged between the surface film and the foam sheet.
The lining is a heat insulating sheet characterized by having at least a cloth made of an olefin resin fiber. The heat insulating sheet according to claim 1, wherein the outer material and the lining are bonded to the foam sheet via an extruded film made of an olefin resin. The heat insulating sheet according to claim 1 or 2, wherein the extruded film that joins the outer material and the foam sheet is formed thicker than the extruded film that joins the foam sheet and the lining. The heat insulating sheet according to claim 2 or 3, wherein the extruded film is made of an ethylene-methylmethacrylate copolymer resin. A heat insulating box characterized in that a wall surface is formed by the heat insulating sheet according to any one of claims 1 to 4.

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