JP2006057826A - Vacuum heat insulating material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vacuum heat insulating material of high quality capable of keeping high heat insulating performance for a long period by using a jacketing material superior in gas barrier property and anti-pinhole property to stabbing of fine foreign matters. <P>SOLUTION: The jacketing material 13 of this vacuum heat insulating material is a laminated body formed by successively laminating a sealant layer 21, a metallic foil layer 22, a first plastic film layer 23 and a second plastic film layer 24 through adhesive layers 25, 26 from an inner side, and the formation of penetrated pinhole can be prevented by cutting off the propagation of rupture caused by stabbing inside of the laminated body in a case when the foreign matter is stabbed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vacuum heat insulating material that includes a core material and a jacket material, the core material is covered with the jacket material, and the inside is sealed under reduced pressure.

  Conventionally, it has been proposed that a plastic laminate film is provided with a layer having a low peel strength on a part of the laminate film in order to prevent bag breakage and pinholes due to impact on the film.

  For example, in packaging bags that store frozen foods or ice-making products that are mixed with sharp-edged contents, even in a low-temperature distribution environment, the packaging bags may tear due to vibration during transportation, or drop impact due to poor handling Has proposed an impact-resistant packaging material that does not cause broken bags or pinholes.

  FIG. 10 shows a cross-sectional view of a conventional impact-resistant packaging material. The impact-resistant packaging material in FIG. 10 is provided with a printing ink layer 5 on one side of a base material 1 made of a synthetic resin layer except for the seal portion 7 at the periphery of the base material 1. 1 The impact resistant resin layer 2 is provided on the entire top surface, and the sealant layer 4 is further provided on the top surface of the impact resin layer 2 via the adhesive layer 3, or the seal portion around the base material 1 is provided on one surface of the base material 1. 7 is provided, the printing ink layer 5 is provided, the impact-resistant resin layer 2 is provided only on the upper surface of the printing ink layer 5, and the sealant layer is formed on the entire upper surface of the base material 1 from the impact resin layer 2 through the adhesive layer 3. 4 (see, for example, Patent Document 1).

The conventional impact-resistant packaging material contains ice or the like, and even if the impact is applied from the outside due to dropping or the like and the base material 1 is broken, the printing ink layer 5 having a weak peeling strength is peeled off. It prevents the occurrence.
JP 2003-340972 A

  However, when the laminate film constituting the conventional impact-resistant packaging material is applied as the outer cover material of the vacuum heat insulating material, the laminate film is pressed against the core material by atmospheric pressure, so that it cannot be covered in close contact with the core material. The surplus laminate film folds itself to form countless wrinkles. As a result, in the laminate film having the printing ink layer having a weak peel strength, there is a problem that the film bases are easily peeled off by wrinkles generated in the printing ink layer portion.

  Further, the purpose of the pinhole-resistant in the conventional packaging material is mainly to prevent tearing due to impact and to prevent piercing by a bulk content having a certain shape such as an iced product. Therefore, the effect of pinhole resistance has not been sufficient for pinholes caused by fine foreign matters such as glass fibers and dust, which are problematic as pinholes in the jacket material of the vacuum heat insulating material.

  Moreover, unlike a normal vacuum package, a vacuum heat insulating material needs to maintain a high vacuum for a long period of time, such as 10 years, and a laminate film requires a high gas barrier property. For this reason, the conventional packaging material has a poor thermal barrier performance over time due to insufficient gas barrier properties, and cannot be applied as a jacket material for vacuum heat insulating materials.

  The present invention solves the above-mentioned conventional problems, and provides a laminated film having excellent pinhole resistance and excellent gas barrier properties, thereby providing a high-quality vacuum heat insulating material excellent in heat insulating performance over a long period of time. The purpose is to provide.

  In order to solve the above-described conventional problems, the present invention provides a vacuum heat insulating material in which a core material is covered with an outer cover material composed of a metal foil layer or a plastic laminate film having a vapor deposition layer, and the inside is decompressed. Is a laminate composed of at least two layers of plastic film and a laminated portion of the plastic film, and when a foreign object is pierced, the propagation of breakage due to piercing is interrupted at any of the inside of the laminate. This prevents the generation of through pinholes.

  With the above configuration, when pierced by a small object such as foreign matter or dust existing on the surface of the core material of the vacuum heat insulating material, the film pierced by the foreign matter is spread outward by compression of the film. When the film breaks, the compressive force spreads outward from the piercing center, so that the tensile force acting from the piercing center to the outer side is transmitted to the outer film laminated to the film through the adhesive layer. It propagates as a force, that is, a shear force.

  However, when the shearing force at which the adhesive layer breaks is smaller than the shearing force at which the outer film breaks, the adhesive layer is broken by the shearing force, so that the foreign substance piercing force is weakened. As a result, the propagation of the piercing force is blocked, and the occurrence of through pinholes in the laminate film can be suppressed.

  Furthermore, if an interface having a low shear strength exists in the laminate film, the interface having a low shear strength or peel strength peels off due to the shearing force, and the piercing force is weakened. As a result, the propagation of the piercing force is blocked, and the occurrence of through pinholes in the laminate film can be suppressed.

  Thus, by providing a layer having a low shear strength or an interface having a low shear strength in a part of the laminate, a laminate film having excellent pinhole resistance while ensuring sufficient peel strength is provided. be able to.

  Moreover, since the said laminate film is a plastic laminate film which has a metal foil layer or a vapor deposition layer, there is no problem also about gas barrier property, and the vacuum heat insulating material excellent in heat insulation performance over a long period of time is obtained.

  The vacuum heat insulating material of the present invention is provided with a covering material made of a laminate film having excellent pinhole resistance while ensuring a sufficient gas barrier property as a covering material of the vacuum heat insulating material. A high quality vacuum heat insulating material having excellent heat insulating performance can be provided.

  The invention according to claim 1 is a vacuum heat insulating material in which a core material is covered with a jacket material composed of a metal foil layer or a plastic laminate film having a vapor-deposited layer, and the inside is decompressed. Of a plastic film and a laminated portion of the plastic film, and when a foreign object is pierced, generation of a penetrating pinhole is created by blocking the propagation of breakage caused by the piercing in any one of the laminated body It is a vacuum heat insulating material to prevent.

  In general, when a foreign object or the like pierces the laminate film, the piercing force of the foreign substance acts as a compressive force, so that the laminate film is broken, that is, pressed. Since the compressive force acts on the laminate film to be pressed so as to spread outward from the center of the press, it acts as a shearing force on the laminate film.

  At this time, if there is a layer having low shear strength inside the laminate film, the layer having the lowest shear strength inside the laminate film breaks and the piercing force is dispersed and relaxed, so the piercing force to the next layer Is blocked from propagating. As a result, it is possible to prevent the generation of through pinholes.

  Similarly, if there is an interface having a low shear strength inside the laminate film, the interface having the lowest shear strength inside the laminate film peels off and the piercing force is dispersed and relaxed. Force propagation is blocked. As a result, it is possible to prevent the generation of through pinholes.

  In addition, when a layer having low shear strength or an interface having low shear strength is present in at least one of the inner layers except the outermost layer and the innermost layer of the laminate film, the piercing force is more efficiently dispersed and relaxed, Propagation of piercing force is blocked. As a result, it is possible to prevent the generation of through pinholes.

  In the invention according to claim 2, the propagation of breakage due to piercing is caused by breakage in any layer of a laminate composed of at least two layers of plastic film and a bonded portion of the plastic film, or any layer The vacuum heat insulating material according to claim 1, which is blocked by peeling at the interface with the layer. Like the action and effect of the invention according to claim 1, propagation of breakage due to piercing is caused by breakage of a layer having weak shear strength, Alternatively, peeling of the interface having a weak shear strength effectively disperses and relaxes the puncture force that gives a rupture of the layer by piercing, that is, a pressing action, thereby blocking the propagation of the piercing force. As a result, penetrating pinholes due to piercing can be prevented.

  The invention according to claim 3 is the vacuum heat insulating material according to claim 2, wherein the layer that breaks is an adhesive layer in a laminate comprising at least two or more plastic films and a bonded portion of the plastic films. It is.

  By breaking the adhesive layer used for the laminate film, it is possible to minimize adverse effects on functions such as barrier properties required for the laminate film. Furthermore, in the laminate film specification design, an arbitrary adhesive layer can be a low shear strength layer, so that the laminate configuration is not limited and a design with a high degree of freedom is possible.

  In general, the elastic modulus of the adhesive and the shear strength of the adhesive are in a proportional relationship, and the shear strength decreases as the elastic modulus decreases. Therefore, since the shear strength of the adhesive is reduced by applying a low-modulus adhesive, the adhesive layer breaks before it penetrates the laminate film when the foreign object pierces. Suppression of through-pinholes can be realized by suppressing propagation of.

  As a means for reducing the elastic modulus of such an adhesive, the urethane resin used as the adhesive has an equivalent ratio of polyisocyanate and polyester polyol of 1 or more and 3 or less, and the urethane resin is aliphatic. This is particularly effective when the urethane resin is made of a polyisocyanate.

  The invention according to claim 4 is the vacuum heat insulating material according to claim 2, wherein the layer to be broken is a plastic film layer in a laminate comprising at least two or more plastic films and a bonded portion of the plastic films. It is.

  By making the layer to be broken into a plastic film, the thickness of the low shear strength layer can be made sufficiently larger than the adhesive layer. Therefore, even in the case of piercing a foreign object with a large force, the piercing force can be easily dispersed and relaxed, and sufficient pin resistance against large foreign objects or foreign objects with a large aspect ratio such as fibers. Hall property can be secured.

  The invention according to claim 5 is a laminate comprising at least two or more plastic films and a bonded portion of the plastic film, and the peeling interface is an adhesive layer, a plastic film layer, a metal foil layer, or It is a vacuum heat insulating material of Claim 2 which is any interface with a vapor deposition layer.

  Similar to the function and effect of the invention according to claim 3, by separating the interface with the adhesive layer adjacent to the laminate film layer, the metal foil layer, or the vapor deposition layer, barrier properties necessary for the laminate film, etc. The adverse effect on the function can be minimized. Furthermore, in the laminate film specification design, an arbitrary adhesive layer can be a low shear strength layer, so that the laminate configuration is not limited and a design with a high degree of freedom is possible.

  In general, the elastic modulus of the adhesive and the shear strength of the adhesive are in a proportional relationship, and the shear strength decreases as the elastic modulus decreases. Therefore, since the shear strength of the adhesive is reduced by applying a low-modulus adhesive, the adhesive layer breaks before it penetrates the laminate film when the foreign object pierces. By blocking the propagation of, penetration pinholes can be suppressed.

  Thus, as means for reducing the elastic modulus of the adhesive, the urethane resin used as the adhesive has an equivalent ratio of polyisocyanate and polyester polyol of 1 or more and 3 or less, and further, the urethane resin is a fat. This was particularly effective when the urethane resin was made of a genus polyisocyanate.

  The invention according to claim 6 is a laminate comprising at least two or more plastic films and a bonded portion of the plastic film, and the peeling interface is an interface between the vapor deposition layer and the vapor deposition base film layer. The vacuum heat insulating material according to claim 2.

  Similar to the above-described action, the rupture of the laminate film due to the piercing is interrupted by the peeling of the interface at the interface having a weak shear strength, so that the piercing force is dispersed and relaxed.

  In particular, when the shear strength at the interface between the vapor deposition layer and the vapor-deposited base film layer is lowered, it has been found that the resistance to pinholes against minute foreign matters such as glass fibers and fine dust is drastically improved. It was.

  Moreover, in order to peel the interface between the vapor deposition layer and the vapor deposition base film layer, it can be realized by using a material having poor vapor deposition quality. This can be realized by coating a deposited film and a resin having high adhesive strength.

  The invention according to claim 7 is a laminate comprising at least two or more plastic films and a bonded portion of the plastic film, wherein the peeling interface is a heat-welded interface of a plastic film produced by coextrusion. It is a vacuum heat insulating material of Claim 2.

  The plastic film produced by coextrusion has low shear strength at the interface where the plastic film is heat-welded. This is due to the low laminate strength at the interface between the heat-welded plastic film and the plastic film, but the pinhole resistance is improved for the same reason as described above.

  Furthermore, the co-extruded film has a high cost merit compared to a laminate film produced by dry lamination, and when this is applicable, a countermeasure for pinhole resistance can be implemented at a low cost.

The invention according to claim 8 is a laminate comprising at least two layers of plastic film and a bonded portion of the plastic film, and the shear strength of any layer of the laminate or any interface is 500 N. It is a vacuum heat insulating material as described in any one of Claim 1 to 7 which is / cm < ² > or less.

A layer having a shear strength of 500 N / cm ² or less, or an interface between layers is easily ruptured or peeled off by a piercing force, and can dampen the piercing force efficiently. In this case, propagation of breakage to the next layer can be blocked.

  The invention according to claim 9 is a laminate comprising at least two or more plastic films and a bonded portion of the plastic film, and the peel strength at any interface of the laminate is 250 N / m or less. It is a vacuum heat insulating material as described in any one of Claim 1 or 2, or Claim 5 to 7.

  An interface having a peel strength of 250 N / m or less is a strength at which peeling can be easily caused by the piercing force and the piercing force can be effectively attenuated. Propagation can be blocked.

  In addition, as for the laminate film which forms the coating | coated material which can be used by this invention, in order to provide high gas barrier property, it is more desirable to comprise with the film made from a plastic which has at least one of a metal foil layer or a vapor deposition layer. At this time, a known material can be used for the metal foil layer and the vapor deposition layer, and is not particularly specified.

  In addition, the lamination film is preferably formed by a dry lamination method using an adhesive for dry lamination, but an extrusion lamination method in which a part of the laminate film is melt extruded using an olefin resin is applied. Also good.

A gravure coater, a reverse coater, or the like can be used for coating the adhesive during dry lamination. The application amount (solid content) of the adhesive is usually ² to 10 g / m ² , and the laminated film after lamination is usually cured at 20 to 50 ° C. for 20 to 120 hours, whereby the adhesive is completely cured.

  On the other hand, the core material usable in the present invention is preferably a glass fiber from the viewpoint of heat insulation performance. The short glass fiber can be used without any problem as long as it is a glass composition that can be made into a fiber. More preferably, the aggregate of short glass fibers comprises a laminate of webs of short glass fibers, and the webs are bonded by the minimum amount of fiber entanglement that can maintain the integrity of the aggregate, and are uniform in the thickness direction. A layered arrangement is preferred.

  Furthermore, in order to suppress the occurrence of pinholes in the outer packaging material, short glass fibers that do not contain foreign matter such as glass shots are more desirable. As a general-purpose industrial product that satisfies such conditions, glass wool is more desirable from the viewpoint of low cost and handling.

  The fiber diameter is not particularly specified, but finer fiber diameter can provide better heat insulation performance. However, it is desirable to use one having an average fiber diameter of 3 to 5 μm from the viewpoint of economy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a vacuum heat insulating material according to Embodiment 1 of the present invention. Moreover, FIG. 2 is sectional drawing of the jacket material of the vacuum heat insulating material in Embodiment 1 of this invention.

  In FIG. 1, the vacuum heat insulating material 11 is configured by inserting a core material 12 and an adsorbent 14 into a jacket material 13 and depressurizing the inside. The vacuum heat insulating material 11 is prepared by drying the core material 12 in a drying furnace at 140 ° C. for 30 minutes, and then inserting the three laminated films into a bag shape by sealing the three sides of the laminated film by heat welding. The pressure inside the jacket 13 is reduced to 13 Pa or less, and the opening is hermetically sealed by heat welding.

  At this time, the jacket material 13 is formed from the inner side in the order of the linear low density polyethylene film (50 μm) as the sealant layer 21, the aluminum foil (6 μm) as the metal foil layer 22, and the polyester terephthalate as the first plastic film layer 23. A nylon film (25 μm) is applied as the film (12 μm) and the second plastic film layer 24.

Further, an adhesive made of a urethane resin is applied between the respective layers, and a laminate film is formed by a dry lamination method so that the amount of adhesive (solid content) is 3.5 g / m ² .

The sealant layer 21 and the metal foil layer 22, and the metal foil layer 22 and the first plastic film layer 23 are laminated using a known urethane adhesive as the adhesive layer 25, and each adhesive layer The shear strength of the laminate including 25 was 1000 N / cm ² .

Further, an adhesive having a low elastic modulus is applied as the adhesive layer 26 between the first plastic film layer 23 and the second plastic film layer 24 and laminated. The shear strength of the laminate including the adhesive layer 26 was 300 N / cm ² . In general, laminating with an adhesive having a low elastic modulus increases the peel strength, but tends to decrease the shear strength.

  In addition, the adhesive material of the adhesive layer 26 is Dick Dry LX-500 / KR-90S, which is an adhesive for aliphatic dry lamination manufactured by Dainippon Ink, and the mixing ratio LX-500: KR-90S = 15: 1. Used.

  On the other hand, the core material 12 is a laminated body of glass fibers in which webs made of short glass fibers are bonded by physical entanglement, and is obtained by laminating glass wool having an average fiber diameter of 3.5 μm until a predetermined density is used. The glass fiber is molded into a board shape by heating and pressing at 450 ° C., which is lower than the strain point of glass, for 5 minutes.

  The adsorbent 14 uses calcium oxide as a moisture adsorbent.

  As for the vacuum heat insulating material 11 produced in this way, it turned out that the product made from pinhole-proof of the jacket material 13 improves dramatically compared with a conventional product. Moreover, it was 0.0026 W / mK when heat conductivity was measured.

  The reason why the pinhole resistance is improved will be described below. When fine foreign matter contained in the core material 12 pierces the outer cover material 13 from the inside, compressive stress mainly acts on the laminate film as the outer cover material 13. When the foreign material stab is pressed against the first plastic film 23, the first plastic film 23 is compressed in the direction of the stab, and when it breaks, the force is released from the center to the outside. It tries to propagate to the plastic film 24.

  However, since the adhesive layer 26 having a low shear strength is provided between the first plastic film 23 and the second plastic film 24, a shearing force acts on the adhesive layer 26. Since the layer 26 breaks, the thrust force is reduced. As a result, the breakage of the first plastic film 23 does not propagate to the second plastic film 24. In this way, it is possible to prevent the occurrence of through pinholes in the jacket material.

  Further, from the viewpoint of materials, the adhesive layer 26 applied between the first plastic film 23 and the second plastic film 24 has an aliphatic polyester polyol and an aliphatic group as a low shear strength adhesive layer. A urethane resin made of a polyisocyanate is used.

  In general, the elastic modulus of the adhesive and the shear strength of the adhesive are in a proportional relationship, and the shear strength decreases as the elastic modulus decreases. Therefore, when a foreign object is pierced, the piercing force is reduced and reduced by breaking the adhesive layer having a low shear strength, so that the propagation of the piercing force of the foreign object is blocked and the generation of pinholes on the upper film can be suppressed. I think.

  From the above results, it is possible to provide excellent insulation over a long period of time by providing a covering material made of a laminate film having excellent pinhole resistance while ensuring sufficient gas barrier properties as a covering material of the vacuum heat insulating material. A high-quality vacuum heat insulating material having performance can be provided.

  In order for the adhesive material to have a low shear strength, it must have a linear molecular structure to some extent in terms of chemical structure, and the isocyanate component preferably has a bifunctional or bifunctional linear structure. .

  Therefore, aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMDI), and lysine diisocyanate (LDI) are particularly effective for exhibiting a low elastic modulus.

  It is also effective to reduce the crosslinking density of the urethane resin that is an adhesive material. Therefore, it is desirable that the equivalent ratio of polyol and polyisocyanate is 1 or more and 3 or less and that polyisocyanate is excessive, and more desirably, the equivalent ratio is 1 or more and 2 or less. That is, it is desirable to mold by reducing the isocyanate component by 10 to 30 wt% from the manufacturer's recommended blending ratio. By applying such an isocyanate, it is possible to reduce the elastic modulus of the urethane resin constituting the adhesive layer, that is, the shear strength.

The lower the shear strength of the laminate including the adhesive layer, the more effective the improvement of pinhole resistance. However, if the shear strength is 100 N / cm ² or less, the outer cover material of the vacuum heat insulating material should be strengthened. When a load is applied to the laminate film such as bending, the laminate film is easily peeled off by shearing. Therefore, it is more preferable that the shear strength is 100 to 300 N / cm ² or less, and more preferably the shear strength is 100 to 200 N / cm ² or less.

  Therefore, by applying the jacket material having such shear strength, a high-quality vacuum heat insulating material that sufficiently satisfies the pinhole resistance and other necessary physical properties can be provided.

(Embodiment 2)
FIG. 3 is a cross-sectional view of the jacket material according to the second embodiment.

  As shown in FIG. 3, the jacket material 13 of the present embodiment includes a linear low-density polyethylene film (50 μm) as the sealant layer 21 and a polyester terephthalate film (first plastic film layer 23) in order from the inside. 12 μm), a nylon film (25 μm) is applied as the second plastic film layer 24.

  Note that a plastic film on which aluminum vapor deposition having a thickness of 500 mm is previously applied as the vapor deposition layer 27 is applied to the second plastic film layer 24 side of the first plastic film layer 23.

  In the adhesive layer, the sealant layer 21 and the first plastic film layer 23, and the first plastic film layer 23 and the second plastic film layer 24 are formed using a known urethane adhesive as the adhesive layer 25. Lamination was performed by dry lamination according to a known method.

  In addition, the vacuum heat insulating material in this Embodiment 2 is the same as that of the manufacturing method in Embodiment 1 except that the material structure of the jacket material 13 differs.

In the laminate film thus produced, the laminate composed of the sealant layer 21 and the first plastic film layer 23 had a shear strength of 1000 N / cm ² . On the other hand, the laminate consisting of the first plastic film layer 23 and the second plastic film layer 24 had a shear strength of 250 N / cm ² . After measuring the shear strength of the laminate, it was confirmed that peeling occurred at the interface between the first plastic film layer 23 and the vapor deposition layer 27.

  As for the vacuum heat insulating material 11 produced in this way, it turned out that the product made from pinhole-proof of the jacket material 13 improves dramatically compared with a conventional product. Moreover, it was 0.0025 W / mK when heat conductivity was measured.

  The factor that improves the pinhole resistance is that when a piercing force by a foreign object is applied to the first plastic film 23, the first plastic film 23 is compressed and extends in a direction perpendicular to the piercing. A pulling force acts on 24 from the center of piercing.

However, since the shear strength of the laminate composed of the first plastic film layer 23, the vapor deposition layer 27, the adhesive layer 25, and the second plastic film layer 24 is as small as 250 N / cm ² , the shear force is applied to the vapor deposition layer 27. Since the action causes peeling at the interface between the first plastic film 23 and the vapor deposition layer 27, the piercing force is reduced and the breakage of the first plastic film 23 is not propagated to the second plastic film 24. Therefore, it is possible to prevent the generation of through pinholes in the jacket material.

  From the above results, it is possible to provide excellent insulation over a long period of time by providing a covering material made of a laminate film having excellent pinhole resistance while ensuring sufficient gas barrier properties as a covering material of the vacuum heat insulating material. A high-quality vacuum heat insulating material having performance can be provided.

  In addition, in order to reduce the shear strength at the interface between the vapor deposition layer and the vapor deposition base film layer, it can be realized by using a vapor deposition film with poor vapor deposition quality. However, if barrier properties are required, vapor deposition is performed in advance. This can be realized by coating the surface of the layer with a vapor deposition film and a resin having high adhesion.

  As the resin having a high adhesive force with the vapor deposition film, a known material can be applied. As an example, if the vapor deposition film is aluminum, a mixture of a polyacrylic acid copolymer and a polyalcohol polymer is effective.

  More preferably, by applying a heat treatment at around 200 ° C. after coating the mixture, the adhesion between the deposited film and the coating agent is further increased, and the bonding force between the substrate film and the deposited film is determined from the thermal expansion of the substrate film. Is more desirable than weakening.

(Embodiment 3)
FIG. 4 shows a cross-sectional view of the jacket material according to the third embodiment.

  As shown in FIG. 4, the jacket material 13 includes, in order from the inside, a linear low-density polyethylene film (50 μm) as the sealant layer 21, an aluminum foil (6 μm) as the metal foil layer 22, and a first plastic film layer. A nylon film (15 μm) is applied as 23, and a nylon film (25 μm) is applied as the second plastic film layer 24.

  Further, the first plastic film layer 23 and the second plastic film layer 24 are formed as a coextruded film layer 28 laminated by coextrusion.

  Further, the sealant layer 21 and the metal foil layer 22, and the metal foil layer 22 and the first plastic film layer 23 are laminated using a known urethane adhesive as the adhesive layer 25.

  In addition, the manufacturing method of the vacuum heat insulating material in this Embodiment is the same as that of Embodiment 1 except that the material structure of the jacket material 13 differs.

In the laminate film thus produced, the laminate composed of the sealant layer 21, the metal foil layer 22, the first plastic film layer 23, and the adhesive layer 25 had a shear strength of 1000 N / cm ² .

On the other hand, the laminate consisting of the first plastic film layer 23 and the second plastic film layer 24 had a shear strength of 150 N / cm ² . After measuring the shear strength of the laminate, it was confirmed that peeling occurred at the interface between the first plastic film layer 23 and the second plastic film layer 24.

  As for the vacuum heat insulating material 11 produced in this way, it turned out that the product made from pinhole-proof of the jacket material 13 improves dramatically compared with a conventional product. Moreover, it was 0.0025 W / mK when heat conductivity was measured.

  The reason why the pinhole resistance is improved is that when the piercing of the foreign matter is pressed against the first plastic film 23, the first plastic film 23 is compressed in the direction of the piercing and from the center to the outer side at the time of breaking. The force is released and the force tries to propagate to the second plastic film 24.

However, since the laminate composed of the first plastic film layer 23 and the second plastic film layer 24 has a small shear strength of 150 N / cm ² , the first strength is applied when the shear force acts on the first plastic film 23. Since peeling has occurred at the interface between the plastic film layer 23 and the second plastic film layer 24, the piercing force is reduced and the breakage of the first plastic film 23 is not propagated to the second plastic film 24. I think. Therefore, it is possible to prevent the occurrence of through pinholes in the jacket material.

  From the above results, it is possible to provide excellent insulation over a long period of time by providing a covering material made of a laminate film having excellent pinhole resistance while ensuring sufficient gas barrier properties as a covering material of the vacuum heat insulating material. A high-quality vacuum heat insulating material having performance can be provided.

(Embodiment 4)
FIG. 5 is a cross-sectional view of the jacket material of the vacuum heat insulating material in Embodiment 4 of the present invention.

  In FIG. 5, the jacket material 13 includes, in order from the inside, a linear low density polyethylene film (50 μm) as the sealant layer 21, an aluminum foil (6 μm) as the metal foil layer 22, and ethylene as the first plastic film layer 29. A nylon film (25 μm) is applied as the vinyl alcohol copolymer resin film (12 μm) and the second plastic film layer 24.

  As the adhesive layer, the sealant layer 21 and the first plastic film layer 23, and the first plastic film layer 23 and the second plastic film layer 24 are known by using a known urethane adhesive as the adhesive layer 25. It laminated | stacked by the dry lamination by the method of.

  On the other hand, an ethylene-vinyl alcohol copolymer resin film (12 μm) is applied to the first plastic film layer 29, and this resin is used as a plastic film layer having a low shear strength.

  In addition, the vacuum heat insulating material in this Embodiment is the same as that of the preparation method in Embodiment 1 except that the material structure of the jacket material 13 differs.

In the laminate film thus produced, the shear strength of the laminate including the first plastic film layer 29 was 300 N / cm ² . After measuring the shear strength of the laminate, it was confirmed that peeling of the interface of the first plastic film layer 29 and rupture of the first plastic film layer 29 itself occurred.

  Further, it has been found that the vacuum heat insulating material 11 is drastically improved by making the outer cover material 13 made of pinholes resistant compared to the conventional product. The thermal conductivity was 0.0025 W / mK.

  As described above, the mechanism for improving the pinhole resistance as described above is that the low shear strength layer is destroyed by the shear force caused by the piercing force from the inside, and the thrust force is reduced and reduced. Generation | occurrence | production of a penetration pinhole can be prevented by interrupting propagation | transmission of a fracture | rupture.

  In the present embodiment, it is considered that the first plastic film 29 functions as a low shear strength plastic film layer.

  The low shear strength plastic film is not limited to the ethylene-vinyl alcohol copolymer resin film, and known materials such as nylon film, polyester terephthalate film, polypropylene film, and polyethylene film can be applied.

  From the above results, it is possible to provide excellent insulation over a long period of time by providing a covering material made of a laminate film having excellent pinhole resistance while ensuring sufficient gas barrier properties as a covering material of the vacuum heat insulating material. A high-quality vacuum heat insulating material having performance can be provided.

  As an example of the method for measuring the shear strength of the laminate in the present invention, it can be carried out according to the test method of JIS K6850. Specifically, as shown in FIG. 6, a laminate having a low shear strength layer or interface, in which a metal plate 30 or the like is bonded to the outermost layer film, and the metal plate 30 is bonded. By performing a tensile test at both ends of the body, the tensile shear strength at the inner layer of the laminate or at the interface between the inner layers can be measured.

(Embodiment 5)
FIG. 7 is a cross-sectional view of the jacket material of the fifth embodiment.

  As shown in FIG. 7, the jacket material 13 of the present embodiment is composed of a linear low-density polyethylene film (50 μm) as the sealant layer 41 and aluminum as the metal foil layer 42 in order from the inside. The laminate film is a foil (6 μm), a polyester terephthalate film (12 μm) as the first plastic film layer 43, and a nylon film (25 μm) as the second plastic film layer 44.

  In this laminate film, there are low peel strength interfaces 45 at the interface between the first plastic film layer 43 and the adhesive layer 46 and at the interface between the second plastic film layer 44 and the adhesive layer 46, respectively.

  In addition, the vacuum heat insulating material in this Embodiment is the same as that of the preparation method in Embodiment 1 except that the material structure of the jacket material 13 differs.

  Further, the sealant layer 41 and the metal foil layer 42, and the metal foil layer 42 and the first plastic film layer 43 are laminated by a known dry lamination method using a known urethane-based adhesive. The interlaminar peel strength was 700 N / m or more.

  Further, the low peel strength interface 45 is 1/10 of the adhesion area of the adhesive in the adhesive layer 46 between the first plastic film 43 and the second plastic film 44 as compared with a known method. In this way, the adhesive strength between the first plastic film 43 and the second plastic film 44 was weakened, and the peel strength was 150 N / m.

  As for the vacuum heat insulating material 11 produced in this way, it turned out that the product made from pinhole-proof of the jacket material 13 improves dramatically compared with a conventional product. Moreover, it was 0.0026 W / mK when heat conductivity was measured.

  A mechanism for improving pinhole resistance in this way will be described. When fine foreign matter contained in the core material 12 pierces the outer cover material 13 from the inside, compressive stress mainly acts on the laminate film as the outer cover material 13. When the foreign material stab is pressed against the first plastic film 43, the first plastic film 43 is compressed in the direction of the stab, and when it is broken, the force is released from the center to the outside. It is going to propagate to the plastic film 44 of.

  However, since there is a low peel strength interface 45 between the first plastic film 43 and the second plastic film 44, the low peel strength interface peels off, so the thrust force is reduced. Therefore, the breakage of the first plastic film 43 does not propagate to the second plastic film 44. In this way, it is possible to prevent the occurrence of through pinholes in the jacket material.

  Further, in this embodiment, the adhesive strength is weakened and the interface of low peel strength is formed by applying in a lattice shape so that the adhesion area of the adhesive becomes 1/10 compared to a known method. Of course, there is no problem even if the interface of low peel strength is formed by controlling the adhesive strength of the adhesive itself.

Note that the lower the peel strength of the laminate including the adhesive layer, the more effective is the improvement of pinhole resistance. However, when the peel strength is 20 N / m or less, the outer cover material of the vacuum heat insulating material is strongly bent. For example, when a load is applied to the laminate film, peeling of the laminate film due to shearing easily occurs. Therefore, the peel strength is more desirably 20 to 200 N / cm ² or less, and further desirably the peel strength is 20 to 100 N / cm ² or less.

  Therefore, by applying the jacket material having such a peel strength, a high-quality vacuum heat insulating material that sufficiently satisfies the pinhole resistance and other necessary physical properties can be provided.

(Embodiment 6)
FIG. 8 is a cross-sectional view of the jacket material of the sixth embodiment.

  As shown in FIG. 8, the jacket material 13 of the present embodiment includes a linear low density polyethylene film (50 μm) as the sealant layer 41 and a polyester terephthalate film (first plastic film layer 43) in order from the inside. 12 μm), a nylon film (25 μm) is applied as the second plastic film layer 44.

  Note that a plastic film on which aluminum vapor deposition having a thickness of 500 mm is applied in advance as the vapor deposition layer 47 is applied to the second plastic film layer 44 side of the first plastic film layer 43. A low peel strength interface 45 exists at the interface between the vapor deposition layer 47 and the first plastic film layer 43.

  In addition, the manufacturing method of the vacuum heat insulating material in this Embodiment is the same as the manufacturing method in Embodiment 1 except the constituent materials of the jacket material 13 differing.

  The sealant layer 41 and the first plastic film layer 43, and the first plastic film layer 43 and the second plastic film layer 44 are laminated by a known dry lamination method using a known urethane-based adhesive. The peel strength between the films was 700 N / m or more.

  On the other hand, the low peel strength interface 45 is an interface between the first plastic film 43 and the vapor deposition layer 47, and the peel strength was 200 N / m.

  As for the vacuum heat insulating material 11 produced in this way, it turned out that the product made from pinhole-proof of the jacket material 13 improves dramatically compared with a conventional product. Moreover, it was 0.0025 W / mK when heat conductivity was measured.

  A mechanism for improving pinhole resistance in this way will be described. When fine foreign matter contained in the core material 12 pierces the outer cover material 13 from the inside, compressive stress mainly acts on the laminate film as the outer cover material 13. When the foreign material stab is pressed against the first plastic film 43, the first plastic film 43 is compressed in the direction of the stab, and the force is released from the center to the outside at the time of breakage. Try to propagate to 47.

  However, since there is a low peel strength interface 45 between the first plastic film 43 and the vapor deposition layer 47, this low peel strength interface peels off, so the thrust force is reduced and reduced. The breakage of one plastic film 43 does not propagate to the second plastic film 44.

  Therefore, it is possible to prevent the occurrence of through pinholes in the jacket material.

  In addition, in order to reduce the shear strength at the interface between the vapor deposition layer and the vapor deposition base film layer, it can be realized by using a vapor deposition film with poor vapor deposition quality. However, if barrier properties are required, vapor deposition is performed in advance. This can be realized by coating the surface of the layer with a vapor deposition film and a resin having high adhesion.

  As the resin having a high adhesive force with the vapor deposition film, a known material can be applied. As an example, if the vapor deposition film is aluminum, a mixture of a polyacrylic acid copolymer and a polyalcohol polymer is effective.

  More preferably, by applying a heat treatment at around 200 ° C. after coating the mixture, the adhesion between the deposited film and the coating agent is further increased, and the bonding force between the substrate film and the deposited film is determined from the thermal expansion of the substrate film. Is more desirable than weakening.

(Embodiment 7)
FIG. 9 shows a cross-sectional view of the jacket material in the present embodiment.

  As shown in FIG. 9, the jacket material 13 includes a linear low density polyethylene film (50 μm) as the sealant layer 41, an aluminum foil (6 μm) as the metal foil layer 42, and a first plastic film layer in order from the inside. A nylon film (25 μm) is applied as 43, and a nylon film (15 μm) is applied as the second plastic film layer 44.

  Further, the first plastic film layer 43 and the second plastic film layer 44 are laminated by coextrusion to form a coextruded film layer 48.

  On the other hand, the low peel strength interface 45 is an interface between the first plastic film layer 43 and the second plastic film layer 44.

  In addition, the manufacturing method of the vacuum heat insulating material in this Embodiment is the same as the manufacturing method in Embodiment 1 except the constituent materials of the jacket material 13 differing.

  Further, the sealant layer 41 and the metal foil layer 42, the metal foil layer 42 and the first plastic film layer 43, and laminated by a known dry lamination method using a known urethane-based adhesive, The peel strength of each had 700 N / m or more.

  On the other hand, the low peel strength interface 45 is an interface between the first plastic film 43 and the second plastic film 44, and the peel strength was 100 N / m.

  As for the vacuum heat insulating material 11 produced in this way, it turned out that the product made from pinhole-proof of the jacket material 13 improves dramatically compared with a conventional product. Moreover, it was 0.0025 W / mK when heat conductivity was measured.

  A mechanism for improving pinhole resistance in this way will be described. When fine foreign matter contained in the core material 12 pierces the outer cover material 13 from the inside, compressive stress mainly acts on the laminate film as the outer cover material 13. When the foreign material stab is pressed against the first plastic film 43, the first plastic film 43 is compressed in the direction of the stab, and when it breaks, the force is released from the center to the outside. It is going to propagate to the plastic film 44 of.

  However, since there is a low peel strength interface 45 between the first plastic film 43 and the second plastic film 44, the low peel strength interface peels off, so the thrust force is reduced. Therefore, the breakage of the first plastic film 43 does not propagate to the second plastic film 44.

  Therefore, it is possible to prevent the occurrence of through pinholes in the jacket material.

  The low peel strength interface of the laminate in the present invention can be carried out according to the interface that breaks with a small tensile shear force that can be carried out according to the test method of JIS K6850, or according to the test method of JISK6854. It is an interface that peels with a small peel strength.

  As described above, the vacuum heat insulating material according to the present invention has excellent pinhole resistance and can maintain excellent heat insulating performance over a long period of time.

  Therefore, it can be used without any problem for uses such as a refrigerator-freezer, a house, and a housing equipment that require long-term insulation performance. Furthermore, since it has excellent gas barrier properties, it can be effectively used as a heat insulating material for countermeasures against heat damage to information devices such as printing machines, copying machines, liquid crystal projectors, and notebook personal computers.

  In addition, because of its excellent pinhole resistance, it can be applied to a vacuum insulation material such as by bending the vacuum insulation material and processing it into a cylindrical shape, or by compressing the surface of the vacuum insulation material. It has been improved. Therefore, the application property is improved, and it can be easily used even in a place that could not be used conventionally.

Sectional drawing of the vacuum heat insulating material in Embodiment 1 of this invention Sectional drawing of the jacket material of the vacuum heat insulating material in Embodiment 1 of this invention Sectional drawing of the jacket material of the vacuum heat insulating material in Embodiment 2 of this invention Sectional drawing of the jacket material of the vacuum heat insulating material in Embodiment 3 of this invention Sectional drawing of the jacket material of the vacuum heat insulating material in Embodiment 4 of this invention Sectional view of shear strength measurement sample in the present invention Sectional drawing of the jacket material of the vacuum heat insulating material in Embodiment 5 of this invention Sectional drawing of the jacket material of the vacuum heat insulating material in Embodiment 6 of this invention Sectional drawing of the jacket material of the vacuum heat insulating material in Embodiment 7 of this invention Cross section of conventional impact-resistant packaging

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Vacuum heat insulating material 12 Core material 13 Cover material 22 Metal foil layer 25 Adhesive layer 27 Deposition layer 28 Co-extrusion film layer

Claims (9)

  In a vacuum heat insulating material in which a core material is covered with an outer cover material composed of a metal foil layer or a plastic laminate film having a vapor deposition layer and the inside is decompressed, the laminate film is composed of at least two layers of plastic film and the plastic film. A vacuum heat insulating material which is a laminated body including a bonding portion and prevents the occurrence of a through-pinhole by blocking propagation of breakage caused by piercing at any of the inside of the laminated body when the foreign object pierces.   Propagation of breakage due to piercing is blocked by breakage in any layer of a laminate composed of at least two or more plastic films and a bonded portion of the plastic film, or by peeling at the interface between any layers. The vacuum heat insulating material according to claim 1.   The vacuum heat insulating material according to claim 2, wherein the layer that breaks is an adhesive layer in a laminate including at least two or more plastic films and a bonded portion of the plastic films.   The vacuum heat insulating material according to claim 2, wherein the layer that breaks is a plastic film layer in a laminate composed of at least two plastic films and a bonded portion of the plastic films.   In a laminate composed of at least two or more plastic films and a bonded portion of the plastic film, the peeling interface is an interface between the adhesive layer, the plastic film layer, the metal foil layer, or the vapor deposition layer. The vacuum heat insulating material according to claim 2.   The vacuum heat insulation according to claim 2, wherein in the laminate composed of at least two or more plastic films and a bonded portion of the plastic films, the peeling interface is an interface between the vapor deposition layer and the vapor deposition base film layer. Wood.   The vacuum according to claim 2, wherein in the laminate composed of at least two or more plastic films and a laminated portion of the plastic films, the peeling interface is a heat-welded interface of a plastic film produced by coextrusion. Insulation. 2. A laminate comprising at least two or more plastic films and a bonded portion of the plastic film, wherein the shear strength of any layer or any interface of the laminate is 500 N / cm ² or less. The vacuum heat insulating material as described in any one of 7.   From the laminated body which consists of a plastic film of at least 2 or more layers and the bonding part of the said plastic film, the peeling strength of either interface of a laminated body is 250 N / m or less, From Claim 1 or 2 or Claim 5 The vacuum heat insulating material as described in any one of 7.

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