JP2007239771A - Vacuum heat insulation material and heat insulation box body using this material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum heat insulation material having high heat insulation performance and a heat insulation box body using this material, superior in handling performance in laying, without cracking and tearing an external facing bag body, even if large stress is applied to a wall surface stuck with the vacuum heat insulation material. <P>SOLUTION: In the bag body 2 composed of a gas barrier film having a thermal welding layer, a continuous foam hard plastic foaming body is arranged on both obverse-reverse surfaces of a layer composed of any of organic or inorganic fiber or powder or a combination of these. A core material of at least a three-layer constitution is stored. The whole vacuum heat insulation material (t) of sealing the inside under reduced pressure, is heated to the temperature higher by about 5 to 35 °C than a melting point of the thermal welding layer under atmospheric pressure. A non-welded part of the film along a shape of the core material 1, the thermal welding layer of the film and a surface of the core material are thermally welded. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vacuum heat insulating material that does not crack or break the outer bag body even when a large stress is applied to the wall surface to which the vacuum heat insulating material is applied, and a heat insulating box using the same.

  For example, as described in Patent Document 1, a vacuum heat insulating material (VIP) is a bag made of a composite plastic laminate film having excellent gas barrier properties, and an open-cell hard plastic foam, inorganic fiber, or inorganic powder as a core material. An inorganic substance such as a body is housed, the inside is decompressed, and then the laminated portion of the peripheral gas barrier films is heat sealed.

  The vacuum heat insulating material manufactured in this way is arranged between the inner wall material and the outer wall material of the box, and is used in combination by injecting heat insulating material such as hard urethane foam into the remaining space. Yes. At that time, the vacuum heat insulating material is often used by being attached to the inner wall material or the outer wall material. For example, an adhesive is attached to the inner wall surface of the refrigerator with an adhesive, and a product that does not apply a large stress to the wall surface during use, such as a refrigerator, uses, for example, a rubber-based hot melt adhesive. In addition, a two-component reaction-curing adhesive is used for attaching a vacuum heat insulating material to the wall surface of a product in which a large stress is applied to the wall surface, such as a cold storage truck storage or a container for land transportation.

  However, in the case of a container for maritime transportation that is subject to even greater stress, even if the vacuum heat insulating material is firmly attached to the wall surface, the outer bag body adhered to the wall surface and the core material are not fixed. It is only held at atmospheric pressure. Therefore, when a large stress is applied to the wall surface and a large distorting stress is applied to the vacuum heat insulating material, a large displacement occurs between the core material and the exterior bag body, and the exterior bag body is pulled and cracked or torn. There was a risk that the internal vacuum was destroyed. Note that cracks or tears in the outer bag of vacuum heat insulating material are likely to occur not only during use but also when the vacuum heat insulating material is applied to the wall surface, and a single vacuum heat insulating material having a particularly large area. When sticking, careful handling is required for handling.

  For example, in an apartment house such as a condominium, a floor heating panel using a vacuum heat insulating material with high heat insulating performance as a heat insulating material has been proposed in order to improve thermal efficiency without greatly increasing the thickness of the floor. However, when laying vacuum insulation material, if there are foreign objects or fine convex objects at the laying location, the outer bag body of the vacuum insulation material made of plastic laminate film can be easily broken and the insulation performance of the vacuum insulation material will be reduced. There was a case. Therefore, in Patent Document 2, a protective material is pasted on the back surface of the vacuum heat insulating material in advance to improve handling at the time of on-site construction, while a plurality of vacuum heat insulating material cores are provided, and between the core material and the core material. A structure in which the outer bag bodies are heat-welded to each other and each core material is arranged in an independent space so that even if a part of the outer bag body is torn, the heat insulation performance of the entire vacuum heat insulating material can be prevented from being lowered. An efficient heat dissipation panel has been proposed.

  However, in the invention proposed in Patent Document 2, since the core material is divided into small parts, heat conduction between the core material and the core material is large, and high heat insulation performance cannot be expected.

  Further, Patent Document 3 includes a gas barrier outer covering material having a heat welding layer and a plate-like core material, and the core material is sealed under reduced pressure between the outer covering materials facing each other. The invention of a vacuum heat insulating material has been proposed in which the heat-welding layers facing each other are heat-welded so as to follow the shape of the core material by heating and pressurizing the portion including the core material between the jacket materials. .

  The invention proposed in Patent Document 3 uses a hot plate made of an elastic body in heat welding when manufacturing a vacuum heat insulating material, and the presence or absence of a core material between outer jacket materials is used to deform the hot plate. As a result of the absorption, the opposing heat-welded layers are heat-welded so as to follow the core shape. However, in such a welding method by heating and pressing, there is a limit to the deformation of the hot plate made of an elastic body, considering the thickness of the core material. Therefore, a gas barrier film (exterior material) along the four sides of the core material is used. ) Has a problem in that an unwelded portion tends to remain on the side close to the core material. Moreover, since it is necessary to prepare the hot plate comprised with the elastic body corresponding to the magnitude | size of a vacuum heat insulating material separately, there also existed a problem that manufacturing cost started too much.

  Further, Patent Document 4 includes a gas barrier outer covering material having a heat welding layer and a plate-like core material, and the core material is sealed under reduced pressure between the outer covering materials facing each other. The heat insulation layer where the core material is between the jacket materials melts and binds to the surface portion of the core material. An invention of a vacuum heat insulating material in which is thermally welded has been proposed.

According to the invention proposed in Patent Document 4, since the heat-welded layer of the outer cover material is bound to the surface portion of the core material, the advantage that the outer cover material is less likely to break than the conventional vacuum heat insulating material is is there. However, in the invention proposed in Patent Document 4, when manufacturing a vacuum heat insulating material, the core material is put in a vacuum packaging machine in a state of being sandwiched by an outer jacket material, the inside is decompressed, and the inside of the vacuum packaging machine is predetermined by a conveyor. Although it is stopped after being moved a distance and heat-welded by heating and pressurizing with a hot plate, there is a problem that it is too expensive to manufacture in such a large facility where a conveyor or hot plate is indispensable .
JP 2004-162914 A Japanese Patent No. 3690420 Japanese Patent No. 3559035 JP-A-2005-201458

  The present invention does not crack or tear the outer bag body even when a large stress is applied to the wall surface to which the vacuum heat insulating material is applied, and has high heat insulating performance with excellent handling properties when laying. It is an object of the present invention to provide a vacuum heat insulating material and a heat insulating box using the same.

  The structure of the vacuum heat insulating material of the present invention made for the purpose of solving the above problems is that a bag made of a gas barrier film having a heat-welded layer is made of either organic or inorganic fibers or powders or a combination thereof. The whole of the vacuum heat insulating material containing at least three layers of core material provided with open-celled hard plastic foam on the front and back surfaces of the layer and sealed inside under reduced pressure is the heat-welded layer under normal pressure. The film is heated to a temperature about 5 to 35 ° C. higher than the melting point of the film, and the unwelded portion of the film along the shape of the core material, and the heat-welded layer of the film and the surface of the core material are heat-welded. It is what.

  In the above-mentioned configuration, the present invention can use either an open-celled rigid polyurethane foam or an open-celled rigid polystyrene foam as the open-celled rigid plastic foam. The gas barrier film is preferably a laminated film of a metal foil and a plastic film, or a laminated film of a metal or inorganic oxide vapor-deposited film and a plastic film. In addition, the thermal barrier layer of the gas barrier film is made of high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), unstretched polypropylene (CPP), stretched polypropylene (OPP), polyvinylidene chloride ( PVDC), polyvinyl chloride (PVC), ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol copolymer (EVOH) plastic film, or polyamide-based, polyurethane-based, polyester-based, ethylene- A vinyl acetate copolymer system or an olefin type hot melt adhesive can be obtained.

  Moreover, the structure of this invention heat insulation box made | formed for the purpose of solving the said subject is the vacuum in any one of Claims 1-4 in the space between the inner wall material and outer wall material of the box which accommodates articles | goods. A heat insulating material is arranged, and the remaining space is filled with closed cell rigid polyurethane foam.

  Furthermore, another configuration of the heat insulation box of the present invention made for the purpose of solving the above problems is that a vacuum heat insulation material is placed in a space between an inner wall material and an outer wall material of a box body for storing articles. The composite heat insulating material integrally formed with the closed cell rigid polyurethane foam surrounding at least one side and the peripheral side is disposed, and the remaining space is filled with the closed cell rigid polyurethane foam.

  In the vacuum heat insulating material of the present invention, the heat-welded layer of the gas barrier film and the open-cell hard plastic foam of the core material are firmly fixed. The gas barrier film of the bag body is not peeled off from the core material due to a large strain, or is cracked and broken, and the effect of greatly reducing vacuum breakage can be obtained.

  Moreover, since the gas barrier film of the bag body is firmly fixed to the core material surface of the vacuum heat insulating material of the present invention, the tensile strength, shear strength and the like are larger than those of conventional vacuum heat insulating materials. As a result, when placed in the wall of the box and used, the rigidity of the box is increased, and an effect that it can be suitably used for a marine transportation container or the like on which a large strain stress is applied is obtained.

  Further, the core material of the vacuum heat insulating material of the present invention is provided with at least 3 open-cell hard plastic foams on the front and back surfaces of a layer made of either organic or inorganic fibers or powders or a combination thereof. Since it has a layer structure, the surface of the vacuum heat insulating material becomes smooth and the mounting property to the wall surface or the like is improved. In addition, since it has a layer made of at least one of organic or inorganic fibers or powders, or a combination thereof, the heat insulating performance is higher than the case where the core material is only an open-celled hard plastic foam. Good. Furthermore, by changing the ratio of the thickness of the layer made of either organic or inorganic fibers or powders or a combination thereof and the open celled hard plastic foam disposed on both the front and back surfaces, Strength and heat insulation performance can be adjusted according to the purpose of use. In addition, by adjusting the thickness of the open-cell hard plastic foam provided on both the front and back surfaces of the core material, there is an effect that adjustment such as increasing the thickness of the vacuum heat insulating material can be easily performed.

  Next, an embodiment of the present invention will be described with reference to the drawings.

  1 is a cross-sectional view of the vacuum heat insulating material before the entire heating, FIG. 2 is a partially cut perspective view showing a state in which the vacuum heat insulating material of FIG. 1 is heated in a heating furnace, and FIG. 3 shows the vacuum heat insulating material of the present invention. FIG. 4 is a conceptual diagram showing an example of a method for integrally forming a vacuum heat insulating material and a closed cell rigid polyurethane foam, and FIG. 4 (a) is a formwork. FIG. 4 (b) is a view showing a state in which a urethane raw material liquid is injected into the mold W, and FIG. 4 (c) is a cross section of the composite heat insulating material F. FIG. 5 is an enlarged cross-sectional view of a main part showing a state in which the composite heat insulating material F shown in FIG. 4 is arranged in a wall such as a box, and FIG. 6 is a perspective view showing a method of a shear strength test of the vacuum heat insulating material. FIG. 7 is a view showing a manner of attaching the vacuum heat insulating material to the container for marine transportation. FIG. 7 (a) shows the container on the ceiling surface, the floor surface, and the side surface in the longitudinal direction. FIG. 7B is a diagram showing a state in which 40 vacuum heat insulating materials are aligned and pasted, and FIG.

  In the figure, t is a vacuum heat insulating material manufactured by a conventional method. In the present invention, as shown in FIG. 1, the core material 1 is made of either organic or inorganic fibers or powders or a combination thereof. A layer having at least three layers in which open-celled hard plastic foams 1b and 1b are provided on both the front and back surfaces of the combined layer 1a is used. At least 3 layers are the open-celled hard plastic foams 1b and 1b on the front and back outermost layers, and at least one organic or inorganic fiber or powder in the middle layer sandwiched between them, or a combination of these If there is a layer made of the same, it may be four or more layers. Therefore, the middle layer can have a layer structure in which an organic or inorganic fiber or powder, or a layer made of a combination of these, and an open-celled hard plastic foam are laminated. The ratio of the thickness of the layer 1a made of either organic or inorganic fibers or powders, or a combination thereof, and the open-celled hard plastic foams 1b, 1b provided on the front and back surfaces is (1b + 1b): 1a = 1: 1 is most preferable from the viewpoint of balance between strength and heat insulation performance.

  Reference numeral 2 denotes a bag made of a gas barrier film having a heat-welded layer. The vacuum heat insulating material t is manufactured by sealing the interior of the core member 1 in a reduced pressure state while the core material 1 is housed. In addition, 2a is the sealing part which sucked the inside of the bag body 2 to the state close | similar to a vacuum, and was heat-sealed. Reference numeral 3 denotes a gas adsorbent disposed at an arbitrary position of the core material 1 for absorbing the outgas generated from the core material 1 over time and the heat seal portion, and the gas entering over time from the film surface. Is.

  As the open-cell hard plastic foam 1b constituting the core material 1 of the vacuum heat insulating material t, open-cell hard polyurethane foam, open-cell hard polystyrene foam, or the like can be used. In addition, you may use what made the molded object of the laminated structure which carried out the multistage compression molding for these foams.

  Moreover, as a layer which consists of organic or inorganic fiber or powder which comprises the core material 1, or those which combined these, the layer which consists only of organic fiber, the layer which consists only of inorganic fiber, organic fiber and inorganic Examples thereof include a layer using a mixture of fibers, or a layer formed by mixing one or both of organic or inorganic powders with these fiber layers. Furthermore, the layer which consists only of organic powder or inorganic powder, or the layer which consists of what mixed organic and inorganic powder is mentioned.

  As the fiber body, glass fiber, ceramic fiber, rock wool, silica alumina wool or the like can be used as the inorganic fiber. In addition, as the organic fibers, polyester fibers such as PET fibers, polyolefin fibers such as PP fibers, polyamide fibers such as nylon fibers, or plant-derived fibers such as kenaf fibers and banana fibers can be used. . As the powder, a known material mainly composed of dry silica, wet silica, pearlite or the like can be used as the inorganic powder. Moreover, powder, such as kenaf, can be used for the organic powder. For example, glass fiber mats or kenaf fiber mats formed by applying 0.5 to 1.5 wt% organic binder to glass fiber, laminated, and compression molded, or glass fiber compressed by needle punch without applying a binder or other binder A mat, a mixture of glass fiber and PET fiber, a glass fiber mat or the like obtained by collecting cotton fibers using water and then compression-molding them can be used.

  Next, the gas barrier film used for the bag 2 of the vacuum heat insulating material t is formed of a composite plastic laminate film. Specifically, the heat-welding layer, the metal foil, and another plastic film are laminated, and the heat-welding layer is located in the innermost layer of the bag body 2.

  As the metal foil, aluminum foil, steel foil, stainless steel foil, copper foil or the like can be used. Instead of the metal foil, a metal or inorganic oxide vapor-deposited film can be used and a film laminated with a plastic film can also be used.

  In addition, as the heat welding layer, high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), unstretched polypropylene (CPP), stretched polypropylene (OPP), polyvinylidene chloride (PVDC), Plastic film such as polyvinyl chloride (PVC), ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol copolymer (EVOH), or polyamide, polyurethane, polyester, ethylene-vinyl acetate copolymer An olefin-based hot melt adhesive can be used.

  As an example of the above composite plastic laminate film, there is a laminate film having a four-layer structure of polyethylene terephthalate film / nylon film / aluminum foil / polyethylene film. In addition, polyethylene terephthalate film / aluminum foil / high density polyethylene film There is also a laminate film having a three-layer structure, and when these films are formed on the bag body 2, the polyethylene film is configured to be inside the bag body 2. The above laminated film aluminum foil is replaced with a film in which an inorganic oxide is deposited, such as an aluminum deposited film, an alumina deposited film, a silica deposited film, or a binary deposited film in which two kinds of inorganic oxides are laminated on one substrate. Of course, it can also be used.

  The vacuum heat insulating material T of the present invention heats the entire vacuum heat insulating material t having the above structure to a temperature of about 5 to 35 ° C. higher than the melting point of the heat-welded layer of the gas barrier film under normal pressure to form the outer peripheral shape of the core material 1. The non-welded portion of the gas barrier film along and the heat-welded layer of the gas barrier film and the surface of the core material are heat-welded. As a method of heating the entire vacuum heat insulating material t under normal pressure, for example, there is a method of heating the vacuum heat insulating material t in the heating furnace R as shown in FIG. In FIG. 2, the vacuum heat insulating material t is heated one by one. However, a plurality of vacuum heat insulating materials t may be placed in a larger heating furnace and heated at the same time, or conveyed by a conveyor or the like. You may make it heat, feeding in a heating furnace sequentially. Note that D is an opening / closing door of the heating furnace R, and h is a handle of the opening / closing door D.

  The heating temperature is set to a temperature about 5 to 35 ° C. higher than the melting point of the heat-welded layer of the gas barrier film. For example, if the heat-welded layer is a high-density polyethylene (HDPE) film, the HDPE has a density of 0.93 to 0.95, and the melting point is 120 to 130 ° C. If the film is a linear low-density polyethylene (LLDPE), the density of the LLDPE Is 0.91-0.93, melting point is 100-110 ° C. Similarly, in the case of unstretched polypropylene (CPP), the density of CPP is around 0.90 and the melting point is 130-170 ° C, so it is 5 from the melting point of HDPE, LLDPE, CPP. Set the temperature to about 35 ℃ higher.

By heating the entire vacuum heat insulating material t under normal pressure as described above, the unwelded portion on the side close to the core material 1 is reliably heat-welded with the opposing heat-welding layer of the gas barrier film of the bag 2. Can be made. Further, in the vacuum heat insulating material t, the heat-welded layers of the open-cell hard plastic foams 1b and 1b on both the front and back surfaces of the core material 1 and the gas barrier film 2 are adhered only by pressure reduction, and are welded. Absent. When the entire vacuum heat insulating material t is heated under normal pressure in this state, the heat-welded layer of the gas barrier film is reliably heat-welded to the open-cell hard plastic foam 1b. In the vacuum heat insulating material T of the present invention manufactured as described above, the open cell hard plastic foam 1b of the core material 1 and the heat-welded layer of the gas barrier film are fixed with a force of 1.1 kgf / cm ² or more.

  In the vacuum heat insulating material T of the present invention, the open-cell hard plastic foams 1b and 1b are provided in the outermost layer of the core material 1 so that the heat-welded layer of the gas barrier film is easily welded as described above. . Moreover, since the open-cell hard plastic foams 1b and 1b are on the front and back of the core material, the surface of the vacuum heat insulating material T becomes smooth, and the adhesiveness with the wall surface to be attached is improved. In particular, when the vacuum heat insulating material T is disposed in the wall of the box, the adhesion with the injected rigid urethane foam is improved. Furthermore, at least one layer of organic or inorganic fibers or powders or a combination of them is provided in the middle layer sandwiched between the open-cell hard plastic foams 1b and 1b of the core material 1. This is because the heat insulating performance can be improved as compared with the case where the core material is only an open-cell hard plastic foam. In addition, by adjusting the thickness of the open-cell hard plastic foams 1b and 1b, the strength and heat insulating performance of the vacuum heat insulating material T can be adjusted according to the intended use while maintaining high heat insulating properties.

  As described above, the vacuum heat insulating material T of the present invention is firmly attached to the heat-bonded layer of the gas barrier film and the open-celled hard plastic foam 1b of the core material 1. Even if it is greatly distorted, the gas barrier film of the bag body 2 is not peeled off from the core material 1, and the vacuum break can be greatly reduced. Further, as will be described in detail later, since the strength (tensile strength, shear strength, bending strength) of the vacuum heat insulating material T is increased, for example, when placed in the wall of the box, the rigidity of the box is increased and large distortion occurs. It can be applied to marine transport containers that are under stress. That is, in a marine shipping container, a plurality of vacuum heat insulating materials T are arranged and adhered to the wall surface, but a large stress is applied to the wall surface of the container during transportation of the container or loading / unloading with a crane, and the vacuum heat insulating material. The entire T is distorted. However, even in such a case, the vacuum heat insulating material T of the present invention is such that the gas barrier film of the bag body 2 is not peeled off or displaced from the core material 1, so that the gas barrier film is cracked or torn. No, high thermal insulation performance can be maintained over a long period of time.

  The vacuum heat insulating material T of the present invention is not only a refrigerator or freezer that does not apply great stress to the wall surface, but also floor heating panels and wall heat insulating materials in houses such as apartments, heat insulating materials in air conditioning equipment and various mechanical equipment, factories and warehouses. It can also be used as a heat insulating material for walls and partition panels, or as a heat insulating material for luggage compartments for land transportation vehicles and containers for land transportation.

  Next, the structure of the heat insulation box used for the vacuum heat insulating material T of the present invention in a box shape including the above-described container for sea transportation, for example, a cooler box or a container for land transportation will be described. FIG. 3 shows a configuration in which the vacuum heat insulating material T is arranged in the space between the inner wall material 4a and the outer wall material 4b of the heat insulating box 4 as described above. In the heat insulating box 4 shown in FIG. 3, the vacuum heat insulating material T is directly attached to the outer wall material 4b, and the remaining space is filled with the closed cell rigid polyurethane foam 5 so that the vacuum heat insulating material T is not displaced in the wall. In addition, the polyurethane foam 5 supplementarily improves the heat insulation performance. The vacuum heat insulating material T may be affixed to the inner wall material 4a, may be affixed to the outer wall material 4b, or may be disposed at an intermediate portion between the inner wall material 4a and the outer wall material 4b.

  When the vacuum heat insulating material is disposed in the space between the inner wall material 4a and the outer wall material 4b of the heat insulating box 4, the vacuum heat insulating material may be bent or twisted, and may not be adhered to the wall surface. Moreover, the vacuum heat insulating material may be struck by the bumps in the operation, or particularly the corners of the vacuum heat insulating material may be damaged. In consideration of such a case, the vacuum heat insulating material is put in a mold, and closed cell rigid polyurethane foam is injected and integrally molded to improve the handleability. FIG. 4 shows an example of a method for integrally forming the vacuum heat insulating material and the closed cell rigid polyurethane foam. 4 (a) shows a state in which the vacuum heat insulating material (VIP) is put into the formwork W whose upper surface is opened, and FIG. 4 (b) shows the heat-sealed sealing portion at the periphery of the vacuum heat insulating material. 2 shows a state in which the urethane raw material liquid is injected from the raw material injector P into the mold W. Note that it is desirable that the sealing portion at the periphery of the vacuum heat insulating material is folded before the vacuum heat insulating material is put into the mold W. Further, the folding may be downward or no folding. After injecting the urethane raw material liquid, if the upper surface of the mold W is covered and cured for about 15 minutes, a composite heat insulating material F as shown in FIG.

  FIG. 5 shows that a composite heat insulating material F integrally formed of a vacuum heat insulating material and a closed cell rigid polyurethane foam is arranged in a space between the inner wall material 4a and the outer wall material 4b of the heat insulating box 4, and the closed cell hard material is formed in the remaining space. The state which filled the polyurethane foam 5 is shown. In addition, the vacuum heat insulating material integrally molded with this closed cell rigid polyurethane foam is not limited to the vacuum heat insulating material T heated as described above, and may be the vacuum heat insulating material t before the whole is heated. Further, the vacuum insulating material only of a layer made of any one of organic or inorganic fibers or powders or a combination thereof, or the vacuum insulating material of which the core material is only an open-cell hard plastic foam, or The core material may be a vacuum heat insulating material in which an organic or inorganic fiber or powder or a layer made of a combination of these and an open-celled hard plastic foam are randomly laminated. Thus, by using what accommodated the vacuum heat insulating material in the reinforcement frame W, it can lay rapidly without destroying a vacuum heat insulating material in the narrow space in a wall.

  Next, the vacuum heat insulating material T of the present invention having different sizes, thicknesses, and core materials was manufactured, and the tensile strength, shear strength, and thermal conductivity change with time were measured.

[Example 1: Measurement of tensile strength]
As a core material, a three-layer structure in which an open-celled rigid polyurethane foam having a thickness of 5 mm is laminated on the front and back surfaces of a glass fiber layer is used. This core material is made of polyethylene terephthalate film / aluminum foil / high-density polyethylene. It is housed in a bag formed of a gas barrier film having a three-layer structure of film, and after sucking the inside to a state close to vacuum, the periphery is heat-sealed and the structure shown in FIG. Two vacuum insulation materials having a length of 40 mm, a length of 100 mm, and a width of 100 mm were manufactured.
Among them, one vacuum heat insulating material is put in the heating furnace R shown in FIG. 2, and the melting point of the high-density polyethylene film, which is the heat-welded layer of the gas barrier film, is 150 ° C. or higher at 150 ° C. or higher under normal pressure. It heated for 7 minutes, the unwelded part of the gas barrier films close | similar to a core material, the heat welding layer of a gas barrier film, and the surface of a core material were heat-welded, and this invention vacuum heat insulating material was manufactured.
These two vacuum heat insulating materials were subjected to a tensile strength test. For the tensile strength test, two flat plate members with the same size of 100 mm x 100 mm as the vacuum heat insulating material are prepared, and they are bonded to the front and back surfaces of the vacuum heat insulating material with a urethane moisture-curable adhesive. When the agent was sufficiently cured, it was measured by measuring how far the plate member could be tolerated when pulled in a direction away from the surface in a direction perpendicular to the surface. The results were as shown in Table 1 below.

  In Table 1 above, for the vacuum heat insulating material that is not heated, the maximum point load is defined when the gas barrier film is peeled off from the core material surface. As for the vacuum heat insulating material heated as a whole, the gas barrier film was not peeled off from the surface of the core material, but separation occurred in the bonded portion of the glass fiber layer and the open cell rigid polyurethane foam or in the glass fiber layer. The maximum point load was defined when the peripheral edge of the bag body was peeled off from the side surface of the core material.

[Reference Example 1]
Although it is not the vacuum heat insulating material of the present invention, for reference, a bag formed of a gas barrier film having a three-layer structure of polyethylene terephthalate film / aluminum foil / high density polyethylene film using only open-celled rigid polyurethane foam as a core material Two pieces of vacuum insulation material for tensile tests of 15mm in thickness, 50mm in length and 50mm in width, with a thickness of 15mm Two vacuum heat insulating materials for a bending test each having a size of 25 mm in length and 120 mm in width were manufactured. Then, one of them was placed in the heating furnace R shown in FIG. 2, and the whole was heated at a temperature of 150 ° C. for 3 minutes under normal pressure.
A tensile test and a bending test were performed on the vacuum heat insulating materials thus manufactured.

For the tensile test, as in Example 1, two flat plate members with a size of 50 mm x 50 mm were prepared, and these were bonded to the front and back surfaces of the vacuum heat insulating material for the tensile test with urethane-based moisture-curing adhesive. When the adhesive was sufficiently cured, the plate member was measured by measuring how far it could be withstood when the plate members were pulled in a direction away from the surface in a direction perpendicular to the surface.
The bending test can withstand how far when the center of the vacuum insulation material is pushed down with a rod-like material while the vacuum insulation material for bending test is placed on and supported on two struts standing at an interval of 100 mm This was done by measuring. The results were as shown in Table 2 below.

  From Table 2 above, even when only open-celled rigid polyurethane foam is used as the core material, the vacuum heat insulating material heated as a whole has higher bending strength as well as tensile strength compared to the vacuum heat insulating material not heated. I understand that In addition, although the bending test about the vacuum heat insulating material which uses the thing of this invention and the three-layer structure which laminated | stacked the open cell rigid polyurethane foam of thickness 5mm on the surface and the back surface of the layer of glass fiber is not performed. From Table 2, it can be inferred that the bending strength is higher than that of the vacuum heat insulating material that is not entirely heated.

[Example 2: Measurement of shear strength and thermal conductivity]
As the core material, one having a three-layer structure in which open-celled rigid polyurethane foam is laminated on the front and back surfaces of the glass fiber layer is used, and this core material is composed of three layers of polyethylene terephthalate film / aluminum foil / high-density polyethylene film. It is housed in a bag formed of a gas barrier film having a structure, the inside is sucked to a state close to a vacuum, and the periphery is heat-sealed. The structure shown in FIG. Two vacuum insulation materials of 100 mm and 100 mm width were manufactured.
Among them, one vacuum heat insulating material is put in the heating furnace R shown in FIG. 2, and the melting point of the high-density polyethylene film, which is the heat-welded layer of the gas barrier film, is 150 ° C. or higher at 150 ° C. or higher under normal pressure. It heated for 5 minutes, the unwelded part of the gas barrier films close | similar to a core material, the heat welding layer of a gas barrier film, and the surface of a core material were heat-welded, and this invention vacuum heat insulating material was manufactured.
The above vacuum heat insulating material is manufactured by changing the thickness of the front and back open-celled rigid polyurethane foams to 3 mm, 5 mm, and 8.5 mm. Therefore, the thickness of the open-celled rigid polyurethane foam is 3 mm. About the thing which heated the whole thing and the thing of thickness 5mm, what heated the whole thing and the thing which is not heated were manufactured, and the thing which heated the whole thing about 8.5 mm in thickness was manufactured.

Next, only the open-celled rigid polyurethane foam is used as the core material, and this core material is stored in a bag formed of a gas barrier film having a three-layer structure of polyethylene terephthalate film / aluminum foil / high density polyethylene film. Then, after the inside was sucked to a state close to vacuum, the periphery was heat-sealed to produce two vacuum heat insulating materials having a total size of 25 mm in thickness, 100 mm in length, and 100 mm in width.
Among them, one vacuum heat insulating material is put in the heating furnace R shown in FIG. 2, and the melting point of the high-density polyethylene film, which is the heat-welded layer of the gas barrier film, is 150 ° C. or higher at 150 ° C. or higher under normal pressure. It heated for 5 minutes, the unwelded part of the gas barrier films close | similar to a core material, the heat welding layer of a gas barrier film, and the surface of a core material were heat-welded, and the vacuum heat insulating material used as the comparative example 1 was manufactured.

Next, only glass fiber is used as the core material, and the core material is stored in a bag formed of a gas barrier film having a three-layer structure of polyethylene terephthalate film / aluminum foil / high density polyethylene film, Was sucked to a state close to vacuum, and the periphery was heat-sealed to produce one vacuum heat insulating material having a total size of 20 mm in thickness, 100 mm in length, and 100 mm in width. It is placed in the heating furnace R shown in FIG. 2 and heated under normal pressure for 5 minutes at a temperature of 150 ° C., a melting point of 120 to 130 ° C. or higher, of a high-density polyethylene film that is a heat-welded layer of the gas barrier film. The heat insulation layer of the gas barrier film and the surface of the core material were welded as much as possible to produce a vacuum heat insulating material as Comparative Example 2.
Each vacuum heat insulating material obtained by the above manufacturing method was subjected to a shear strength test. As shown in FIG. 6, in the shear strength test, a contact test piece was attached to the front and back surfaces of the vacuum heat insulating material with a urethane-based moisture-curing adhesive, and after sufficient adhesion, the test piece was pulled in the direction of the arrow. It was done by measuring how far it could withstand. The adhesive surface is 50 × 100 mm. In addition, the thermal conductivity of these vacuum heat insulating materials was also measured. The results were as shown in Table 3 below.

From Examples 1 and 2, both the tensile strength and shear strength are approximately atmospheric pressure strength (1.0 kgf / cm ² ) when not heated as a whole. However, when the whole is heated, the core material is only open-celled rigid polyurethane foam, and the open-celled rigid polyurethane foam is laminated on the front and back surfaces of the glass fiber layer as in the vacuum heat insulating material of the present invention. In the three-layer structure, it can be seen that the strength is increased by welding (adhering) the surface of the core material and the heat-welded layer of the gas barrier film of the bag. Further, from Example 2, the shear strength increases in accordance with the thickness of the urethane foam in the case where the core material has a three-layer structure in which an open-celled rigid polyurethane foam is laminated on the front and back surfaces of the glass fiber layer. I understand.

By the way, in order to use vacuum insulation for products that are subject to great stress, such as containers for sea transportation, is the tensile strength (self-adhesive strength) of the container wall face material and injected urethane foam equal to 1.4 kgf / cm ² ? Further strength is necessary for the vacuum heat insulating material, and as an evaluation, tensile strength and shear strength were measured in Examples 1 and 2. Particularly in Example 2, when the ratio of the thickness of the glass fiber layer and the total thickness of the open-celled rigid polyurethane foam on the front and back surfaces is 1: 1, the strength required for use in a container is 1.4 kgf / cm ² . It is found that the thermal conductivity at that time is 0.0025 (W / m · K), which is the most preferable ratio.

[Example 3: Strength test in a state in which the vacuum heat insulating material is disposed in the wall of the box]
Tensile strength and shear strength were measured in a state where closed-cell rigid polyurethane foam was laminated on both sides of the vacuum heat insulating material.

[Tensile strength test]
As the core material, one having a three-layer structure in which open-celled rigid polyurethane foam is laminated on the front and back surfaces of the glass fiber layer is used, and this core material is composed of three layers of polyethylene terephthalate film / aluminum foil / high-density polyethylene film. It is housed in a bag formed of a gas barrier film having a structure, the inside is sucked to a state close to a vacuum, and the periphery is heat-sealed. The structure shown in FIG. A vacuum heat insulating material of 100 mm and 100 mm in width was manufactured.
This vacuum heat insulating material is placed in the heating furnace R shown in FIG. 2, and heated at 150 ° C. for 10 minutes at a temperature of 120 to 130 ° C. or higher of the high-density polyethylene film that is a heat-welded layer of the gas barrier film under normal pressure. The unwelded portion between the gas barrier films close to the core material, the heat-welded layer of the gas barrier film, and the surface of the core material were thermally welded.
A test piece was obtained by laminating a layer of closed-cell rigid polyurethane foam having a thickness of 22.5 mm on both surfaces of the vacuum heat insulating material heated as a whole. Lamination is done by placing a vacuum heat insulating material on the lower surface of the injection mold, injecting and foaming urethane raw material into the space above it, taking it out after curing, and then setting the surface where the vacuum heat insulating material is exposed on the surface as the upper surface of the injection mold The urethane material was injected and foamed into the upper space. The test piece was prepared by taking out the composite heat insulating material from the injection mold and then cutting out the portion where the vacuum heat insulating material was present.
In the tensile test, two flat plate members with a size of 100 mm × 100 mm are prepared, and they are bonded to the front and back surfaces of the test piece with a urethane-based moisture curable adhesive, and the adhesive is sufficiently cured. The plate members were measured by measuring how far they could be held when pulled in a direction away from the surface in a direction perpendicular to the surface. The test results are shown in Table 4 below.

[Shear strength test]
The test piece was manufactured in the same manner as the test piece in the above tensile test except that the overall size of the vacuum heat insulating material used was 20 mm in thickness, 200 mm in length, and 200 mm in width.
In the shear strength test, as shown in FIG. 6, the contact test piece was attached to the front and back surfaces of the test piece with a urethane-based moisture-curing adhesive, and after sufficient adhesion, the test piece was pulled in the direction of the arrow. It was done by measuring how far it could withstand. The adhesive surface is 50 × 200 mm. The test results are shown in Table 5 below.

From Example 3, in the case where the composite heat insulating material in which the vacuum heat insulating material and the closed cell rigid polyurethane foam are integrally formed is arranged in the wall of the box, and the remaining space is filled with the closed cell hard polyurethane foam, the vacuum heat insulating material Is placed in the middle, so the tensile strength is 1.45 kgf / cm ² and the shear strength is 1.85 kgf / cm ² , which is even stronger than when the vacuum insulation is attached to the face material. It can be seen that it is more preferable for use in containers.

[Example 4: Thermal insulation performance deterioration acceleration test]
Next, as the core material, a three-layer structure in which open-celled rigid polyurethane foam is laminated on the front and back surfaces of the glass fiber layer is used. The core material is made of polyethylene terephthalate film / aluminum foil / high-density polyethylene film. 1 is housed in a bag formed of a gas barrier film having a three-layer structure, and the inside is sucked to a state close to vacuum, and then the periphery is heat-sealed, and the structure shown in FIG. A 20 mm, 480 mm long, 1000 mm wide vacuum heat insulating material is manufactured and placed in the heating furnace R shown in FIG. The vacuum heat insulating material of the present invention is heated for 10 minutes at a temperature of 150 ° C. to thermally weld the unwelded portion between the gas barrier films close to the core material and the heat-welded layer of the gas barrier film and the surface of the core material. It was produced.

Further, as Comparative Example 1, a bag in which only an open-celled rigid polyurethane foam is used as a core, and the core is formed of a gas barrier film having a three-layer structure of polyethylene terephthalate film / aluminum foil / high-density polyethylene film. After being housed in the body and sucking the inside to near vacuum, the periphery was heat-sealed to produce a vacuum heat insulating material having a total size of 25 mm, length 480 mm, width 1000 mm.
Further, as Comparative Example 2, a glass fiber only core material is used, and the core material is stored in a bag formed of a gas barrier film having a three-layer structure of polyethylene terephthalate film / aluminum foil / high density polyethylene film. Then, after the inside was sucked to a state close to vacuum, the periphery was heat-sealed to produce a vacuum heat insulating material having a total size of 15 mm in thickness, 480 mm in length, and 1000 mm in width.
These vacuum heat insulating materials are all filled with a gas adsorbent.
About these vacuum heat insulating materials, deterioration of heat insulation performance was accelerated | stimulated on 70 degreeC * dry conditions, and the time-dependent change of thermal conductivity was measured. The measurement was performed with HC-074-600 (manufactured by Eihiro Seiki). The measurement results are shown in Table 6 below.

  According to Example 4, the vacuum heat insulating material of the present invention using a three-layer structure in which an open-celled rigid polyurethane foam is laminated on the front and back surfaces of the glass fiber layer on the core material has a rate of increase in thermal conductivity, Compared to a conventional vacuum heat insulating material using only glass fiber or only open-celled rigid urethane foam for the core material, it can be said that the heat insulating performance is equivalent.

[Usage example: Calculation of heat balance of container for sea transport]
Next, the heat balance when using the vacuum heat insulating material of the present invention in a container for marine transportation, when only closed-celled rigid polyurethane (PUF) is injected into the current wall, the conventional core material is open-celled rigid polyurethane. Compared to the case of using vacuum insulation using only foam.
-The dimensions of the container are 2500 x 2500 x 12000 (mm), and the thickness of the insulating wall is 65 mm.
-The size of the vacuum heat insulating material used is 20 mm thick, 500 mm long, and 1000 mm wide.
・ As shown in Fig. 7, the vacuum insulation material is affixed by placing (a) 40 vacuum insulation materials side by side on the ceiling, floor and longitudinal sides of the container. Eight sheets were placed side by side on the side in the hand direction. In addition, closed-cell hard polyurethane is injected into a space other than the vacuum heat insulating material.
・ Measured by setting the outside temperature to 35 ℃ and the inside temperature of the container to minus 20 ℃.
Table 7 shows the comparison results after measuring the heat balance.

  From Table 5, when using a vacuum insulation material (VIP) in a marine shipping container, compared to when only PUF is injected, the core material is 23% when only open-celled rigid polyurethane foam is used. It can be seen that the heat transfer of 31% can be reduced in the case of the vacuum heat insulating material of the present invention using a three-layer structure in which an open-celled rigid polyurethane foam is laminated on the front and back surfaces of the glass fiber layer.

  In the above examples, glass fibers were used as layers composed of either organic or inorganic fibers or powders in the core material or a combination of these, but each of the above layers using materials other than glass fibers In, almost the same measurement results were obtained.

  The vacuum heat insulating material of the present invention stores a core material of at least three layers sandwiched between layers of inorganic fibers or inorganic powders in an open-cell hard plastic foam in a bag body made of a gas barrier film, and the inside is decompressed. The vacuum heat insulating material obtained by post-sealing is heated within a predetermined temperature range under normal pressure, so that the gas barrier film as well as the unwelded portion of the opposing gas barrier film along the shape of the core material can be used. The heat-welded layer of the adhesive film and the surface of the core material are also heat-welded. As a result, the bag body is hardly cracked or torn when the vacuum heat insulating material is applied to the wall surface.

  In addition, even when the vacuum heat insulating material of the present invention is applied to the wall surface of a container for maritime transportation, when a large stress is applied, only the bag body adhered to the wall surface is pulled and peeled off from the core material and torn. Therefore, there is an effect that high heat insulation performance can be maintained over a long period of time. Furthermore, since the vacuum heat insulating material of the present invention only needs to heat the whole vacuum heat insulating material obtained by sealing the inside after reducing the pressure as it is under normal pressure, the manufacturing cost does not increase much, and not a plurality of core materials. Since it can be applied to a large area vacuum heat insulating material containing a large core material, it can be suitably used for a large box such as a container for sea transportation. In addition, since the vacuum heat insulating material of this invention does not have an unwelded part in the junction part of the gas-barrier films of the bag body in a core material periphery, it can also attach a fixing tool to a periphery.

Sectional drawing of the vacuum heat insulating material before whole heating. FIG. 2 is a partially cut perspective view showing a state where the vacuum heat insulating material of FIG. 1 is entirely heated in a heating furnace. The principal part expanded sectional view which shows the state which has arrange | positioned this invention vacuum heat insulating material in the wall of a box. FIG. 4 (a) is a conceptual diagram showing an example of a method for integrally forming a vacuum heat insulating material and a closed cell rigid polyurethane foam, and FIG. 4 (a) is a view showing a state in which a vacuum heat insulating material (VIP) is put into a mold W. FIG. 4 (b) FIG. 4C is a view showing a state in which the urethane raw material liquid is injected into the mold W, and FIG. 4C is a cross-sectional view of the composite heat insulating material F. The principal part expanded sectional view which shows the state which has arrange | positioned the composite heat insulating material F shown in FIG. 4 in walls, such as a box. The perspective view which shows the method of the shear strength test of a vacuum heat insulating material. Fig. 7 (a) is a diagram showing how the vacuum heat insulating material is attached to a container for marine transportation. FIG. 7B is a diagram showing a state where eight sheets are arranged and pasted on the side surface in the lateral direction.

Explanation of symbols

1 Core material
1a Layer made of inorganic fiber or inorganic powder
1b Open cell rigid plastic foam 2 Bag
2a Sealing part 3 Gas adsorbent 4 Thermal insulation box 5 Closed cell rigid polyurethane foam t, T Vacuum insulation F Composite insulation R Heating furnace D Opening door h Handle W Reinforcement frame

Claims (6)

  An open-celled hard plastic foam was provided on both the front and back surfaces of a layer made of organic or inorganic fibers or powders or a combination of these on a bag made of a gas barrier film having a heat-welded layer. The entire vacuum heat insulating material containing at least a three-layer core material and sealed under reduced pressure is heated to a temperature of about 5 to 35 ° C. higher than the melting point of the heat-welded layer under normal pressure to form the core material. The vacuum heat insulating material characterized by heat-welding the unwelded part of the said film which followed, the heat welding layer of the said film, and the surface of the said core material.   2. The vacuum heat insulating material according to claim 1, wherein the open-cell hard plastic foam is one of open-cell hard polyurethane foam and open-cell hard polystyrene foam.   The vacuum heat insulating material according to claim 1 or 2, wherein the gas barrier film is a laminated film of a metal foil and a plastic film, or a laminated film of a deposited film of a metal or an inorganic oxide and a plastic film.   High-temperature polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), unstretched polypropylene (CPP), stretched polypropylene (OPP), polyvinylidene chloride (PVDC), polyvinyl chloride (PVC), any plastic film of ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol copolymer (EVOH), or polyamide-based, polyurethane-based, polyester-based, ethylene-vinyl acetate copolymer system, The vacuum heat insulating material according to any one of claims 1 to 3, which is an olefin-based hot melt adhesive.   The vacuum heat insulating material according to any one of claims 1 to 4 is disposed in a space between an inner wall material and an outer wall material of a box body that accommodates articles, and the remaining space is filled with closed cell rigid polyurethane foam. Heat insulation box. In the space between the inner wall material and the outer wall material of the box housing the article, a composite heat insulating material is integrally formed with the closed cell rigid polyurethane foam surrounding the vacuum heat insulating material around at least one side and the peripheral side of the heat insulating material, A heat-insulating box characterized by filling the remaining space with closed-cell rigid polyurethane foam.

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