KR20160079618A - Laminated Structure and Vacuum Insulating Material Including Laminated Structure - Google Patents

Abstract

Disclosed is a laminated structure which may effectively reduce a heat bridge, may be excellent in workability, and may prevent pinholes and cracks from being generated. The laminated structure includes at least one polymer layer, a gas barrier layer, and at least one polymer layer in this sequence, wherein adhesive layer are interposed between the layers, the gas barrier layer has a thermal resistance of 650 K/W or more and Young′s modulus of 100 GPa or more, and the position of a neutral axis expressed as the following equation is positioned in the gas barrier layer: (Equation) In the equation, y is a distance from a top surface of compression side bent to the neutral axis, Ei is Young′s modulus of the i^th layer, Si is a first moment of a section of the i^th layer, Ai is a cross-sectional area of the i^th layer, n is the number of layers constituting the laminated structure and an integer of 5 or more.

Description

[0001] The present invention relates to a laminated structure and a vacuum insulation material using the laminated structure,

The present invention relates to a laminate and a vacuum insulation material using the laminate as an exterior material. Particularly, the present invention relates to a laminate and a vacuum insulator which can effectively reduce the heat bridge, have excellent workability, and are prevented from generating pinholes and cracks.

The vacuum insulation material is formed by vacuum packing a core material or a gas adsorbent with a gas-barrier exterior material, and maintains the interior of the vacuum in a vacuum to suppress thermal conductivity. BACKGROUND ART Vacuum heat insulators are used for electric appliances such as freezers, refrigerators, heaters, vending machines, and housing wall materials due to their low thermal conductivity.

The gas barrier exterior material used to maintain the degree of vacuum inside the vacuum insulation material is composed of a laminate of aluminum foil and plastic in order to prevent intrusion of gas from outside. However, since aluminum has a high thermal conductivity of 237 W / m · K, there is a problem in that a vacuum heat insulator using the laminate as the external material as described above has a large heat bridge around which heat flows around the external material portion.

As a method of reducing the heat bridge of such a vacuum insulator, a laminated body of an aluminum deposition layer and plastic is used on one side of the exterior material (see, for example, Patent Document 1). In order to reduce the thermal conductivity while maintaining the gas barrier property, a vacuum insulation material using a metal foil (iron, lead, tin, stainless steel, or the like) having a low thermal conductivity instead of aluminum foil as the gas barrier layer has been reported See, for example, Patent Document 2).

(Patent Document 1) Japanese Patent Laid-Open No. 61-125577

(Patent Document 2) JP-A-9-137889

However, since the aluminum vapor deposition layer disclosed in Patent Document 1 has a low gas barrier property, invasion of gas from the outside can not be prevented, and it has been difficult to maintain the degree of vacuum inside the vacuum heat insulator for a long period of time.

Since the metal foil disclosed in Patent Document 2 is produced by rolling, the thickness of the metal foil such as iron, lead, tin, and stainless steel becomes as thick as 20 μm (for example, paragraph "0010" of Patent Document 2). As a result, the heat bridge becomes a big problem.

In addition, since the Young's modulus of the metal foil and the plastic is greatly different in the laminate of the metal foil and the plastic, there is a problem in workability in the bending process at the time of manufacturing the vacuum insulation material. In addition, stress is concentrated on the gas barrier layer to cause pinholes and cracks in the sheathing material, and as a result, gas barrier properties are deteriorated.

In addition, the metal foil disclosed in Patent Document 2 has poor processability due to its thickness, and has a problem in that it is hard when bending an excess heat seal portion, which is a factor for inhibiting the flow path during urethane filling, and poor handling property.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a laminated body capable of reducing a heat bridge and having excellent workability, suppressing the occurrence of pinholes and cracks, and a vacuum insulating material using the same. do.

As a result of intensive research to solve the above problems, the inventors of the present invention have found that a material having a predetermined thermal resistance and a Young's modulus is used as a laminate gas barrier layer used as an outer material of a vacuum insulation material, The above problems can be solved, and the present invention has been accomplished.

In other words, the above object is achieved by a laminated body including at least one polymer layer, a gas barrier layer, and at least one polymer layer in this order and interposed therebetween with an adhesive layer interposed therebetween, / W and a Young's modulus of 100 GPa or more, and the position of the neutral axis indicated by the following formula is located in the gas barrier layer.

In the above Equation 1, y is the distance from the upper surface to the neutral axis on the compression side at bending, Ei is the Young's modulus of the i-th layer, Si is the first moment of area of the i-th layer, N is the number of layers constituting the laminate, and is an integer of 5 or more.

According to the present invention, there is provided a laminated body capable of effectively reducing the heat bridge, having excellent workability, suppressing the occurrence of pinholes and cracks, and a vacuum insulation material using the same.

1 is a schematic cross-sectional view showing an example of a vacuum insulator of the present invention.
2 is a schematic cross-sectional view of the laminate of the present invention.

The present invention is a laminated body including at least one polymer layer, a gas barrier layer, and at least one polymer layer in this order and interposed between the respective layers with an adhesive layer interposed therebetween, wherein the gas barrier layer has a thickness of 650 K / And has a thermal resistance and a Young's modulus of 100 GPa or more, and the position of the neutral axis represented by the following formula is located in the gas barrier layer.

(1)

Where Ei is the Young's modulus of the i-th layer, Si is the first moment of area of the i-th layer, Ai is the cross-sectional area of the i-th layer, N is the number of layers constituting the laminate, and is an integer of 5 or more.

According to the present invention, the mechanical neutral axis of the laminate as the exterior material of the vacuum insulation material is located in the gas barrier layer. With such a structure, even when compressed or bent, the gas barrier layer is hardly torn, and pinholes and cracks are hardly generated.

In addition, by controlling the thermal resistance and the Young's modulus of the gas barrier layer to a predetermined range, it is possible to effectively reduce the heat bridge of the exterior material while having excellent processability.

Conventionally, in order to maintain a high degree of vacuum inside the vacuum insulating material, an aluminum foil which is inexpensive and has high gas barrier properties has been used as a gas barrier layer. However, since aluminum has a high thermal conductivity among metals, there is a problem that heat is radiated along the exterior material portion of the vacuum insulation material (heat bridge).

Further, when it is produced by the rolling method, it is difficult to make the thickness to 7 탆 or less from the problem of pinhole or tensile strength, and as a result, there is a limit to increase the thermal resistance.

In order to solve this problem, substitution with a vapor deposition film or a metal foil with a low thermal conductivity has been considered. However, there is a problem that the gas barrier property for maintaining the degree of vacuum in the vacuum insulation material is insufficient in the vapor deposition film. Moreover, even if the metal foil is changed to a metal foil having a low thermal conductivity, it is difficult to produce a foil having a thickness of 10 m or less in the rolling method. In addition, since the Young's modulus of the metal foil greatly differs from the Young's modulus of the plastic laminated with the metal foil, There arises a problem that workability is caused in the bending process, and stress is concentrated on the gas barrier layer and broken.

Thus, in the present invention, a layer structure is designed so that a material having a high thermal resistance is used as a laminate gas barrier layer used as a sheath material, and a mechanical neutral axis is located in the gas barrier layer.

The neutral axis is the axis on which the load is not applied when bent, and the more the load is farther away from the neutral axis, the larger the load.

According to the present invention, since stress applied to the gas barrier layer can be minimized even during compression or bending, a laminated body and a vacuum insulation material excellent in bending resistance can be manufactured.

Therefore, the vacuum heat insulator using the laminate of the present invention can reduce the heat bridge, and is excellent in workability and suppresses occurrence of pinholes and cracks. Therefore, the vacuum insulator using the laminate of the present invention is useful as a vacuum insulator such as a refrigerator or a freezer.

Hereinafter, embodiments of the present invention will be described.

On the other hand, the present invention is not limited to the following embodiments.

The dimensional ratios in the drawings are exaggerated for convenience of explanation, and may differ from the actual ratios.

In the present specification, " X to Y " representing a range means " X or more and Y or less ", and " weight ", " The "mass part" is treated as a synonym.

Unless otherwise noted, the measurement of operation and physical properties is performed under the conditions of room temperature (20 캜 to 25 캜) / relative humidity of 40% to 50%.

[Vacuum Insulation]

1 is a schematic cross-sectional view showing an example of a vacuum insulator of the present invention.

1A, the vacuum heat insulator 1 has a structure in which the core material 7 and the gas adsorbent 8 are contained as two layers of a laminate 2 as two external materials so as to be interposed therebetween. Here, the laminate 2 has at least the gas barrier layer 4 and the polymer layers 3, 5, 5 and 6 laminated on at least one side thereof, preferably three or more (three in total in FIG. 1) (Laminate film).

Then, the gas barrier layer 4 and the polymer layers 3, 5, 6 are bonded to each other via an adhesive layer (not shown).

As described above, by providing the gas barrier layer 4 having a certain heat resistance or more, it is possible to suppress the amount of heat flowing from the periphery along the laminate 2 to a low level. Therefore, by using the layered product (2) according to the present invention, the heat bridge can be efficiently suppressed and / or prevented.

Here, the vacuum insulator 1 is manufactured by manufacturing a bag-shaped exterior material by sealing (for example, heat sealing) the periphery of the laminate 2, (7) and the gas adsorbent (8), lowering the internal pressure in this state, and sealing the opening portion (for example, heat sealing).

Therefore, as shown in Fig. 1, at the edge (end portion) of the laminate 2, there exists a joint portion (seal portion) 9 to which the laminate is joined to each other. As shown in Fig. 1B, the bonding portion 9 is bent toward the vacuum heat insulating material main body portion to become a vacuum insulating material product.

Each member of the vacuum insulator of the present invention will be described below.

On the other hand, since the present invention possesses features in a laminate as an exterior material, members other than the conventional members can be used, and the present invention is not limited to the following embodiments.

(Exterior material)

As shown in Fig. 2, the exterior material includes at least one polymer layer 11, a gas barrier layer 13, and at least one polymer layer 15, 17 in this order, Are stacked via the adhesive layers (12, 14, 16).

In the laminate of the present invention, the gas barrier layer has a thermal resistance of 650 K / W or more.

Further, in the laminate including the gas barrier layer having the Young's modulus of 100 GPa or more, the position of the neutral axis of the laminate is located in the gas barrier layer (Fig. 2).

In the present invention, the core material and the gas adsorbent are enclosed by a sheathing material having a pair of gas barrier properties so as to be sandwiched therebetween from both sides, and the inner pressure is lowered to seal the vacuum insulation material. However, At least one of the laminate having barrier properties is composed of the laminate. It is preferable that both exterior materials consist of the above-mentioned laminate.

When the total number of layers constituting the laminate is n layer and the mth layer from the upper surface of the laminate on the compression side at bending is the gas barrier layer, , the (m-2) th layer, and m + 2, m + 4, ... , and the nth layer is a polymer layer.

M + 1, m + 1, m + 3, ..., m-1 from the upper surface of the laminate on the compression side at the time of bending , and the (n-1) th layer is an adhesive layer.

In this case, n is an integer of 5 or more, preferably an integer of 5 to 13. m is an integer of 3 or more, preferably an integer of 3 to 7;

The position of the neutral axis can be calculated from the Young's modulus and thickness of each of the polymer layer and the gas barrier layer according to the following formula.

(1)

Ei is the Young's modulus of the i-th layer, Si is the first-order moment of the i-th layer, Ai is the cross-sectional area of the i-th layer, And n is an integer of 5 or more.

On the other hand, the position of the neutral axis does not depend on the condition of the bending compression, but the position of the neutral axis when bending under the conditions described in the embodiment described later can be adopted.

In the laminate of the present invention, the material, the thickness, the number of layers, the stacking order, and the like are arranged so that the stress balance is reduced with respect to the polymer layer laminated on both sides of the gas barrier layer, As shown in FIG. In other words, the layer structure can be designed from the Young's modulus and thickness of each layer.

1, the polymer layers 3, 5, and 6 on both sides of the gas barrier layer 4 are shown as a single layer and a two-layer type, respectively. However, the polymer layers may exist as a single layer, Or may exist in two or more kinds of laminated forms.

It is preferable that the laminate according to the present invention has a low thermal conductivity in consideration of the heat insulating property. For this reason, it is preferable that the gas barrier layer also has a low thermal conductivity. Specifically, the thermal conductivity (?) Of the gas barrier layer is preferably 130 W / m · K or less, and more preferably 100 W / m · K or less. When the thermal conductivity is 130 W / m · K or less, an excellent heat bridge suppressing effect is obtained as compared with the existing rolled aluminum foil.

On the other hand, the lower limit is not particularly limited, since the lower the thermal conductivity of the gas barrier layer is, the more preferable is 10 W / m · K or more and 20 W / m · K or more. With such a thermal conductivity, the laminate as the exterior material is excellent in heat insulating property.

On the other hand, the thermal conductivity of the gas barrier layer can be measured by a known measurement method. In the present specification, the thermal conductivity of the gas barrier layer can be measured by the method described in the following examples.

As described above, the use of the laminate according to the present invention solves the heat bridge problem.

Considering the heat bridge suppressing effect, it is preferable that the laminate is thin and the thermal conductivity is low.

In view of the above points, the thermal resistance of the gas barrier layer is required to be a certain value or more, and the gas barrier layer usable for the laminate of the present invention may have a thermal resistance (R) of 650 K / W or more. The gas barrier layer may have a thermal resistance R of at least 750 K / W, for example, a thermal resistance R of at least 1000 K / W, and may have a thermal resistance R of, for example, Lt; / RTI > If the thermal resistance of the gas barrier layer is less than 650 K / W, the effect of suppressing the heat bridge is not sufficiently obtained.

On the other hand, the higher the thermal resistance of the gas barrier layer is, the better, the upper limit is not particularly limited, but usually 20,000 K / W or less is sufficient, and 10,000 K / W or less is sufficient.

Particularly, a laminated body using a gas barrier layer having a heat resistance of 650 K / W or more and a thickness of 10 탆 or less is advantageous in that, in comparison with the case of using a conventional aluminum foil, It is possible to effectively inhibit / prevent it.

In the present specification, the thermal resistance of the gas barrier layer refers to the thermal resistance perpendicular to the thickness direction with respect to the gas barrier layer per unit area, and the thermal resistance R (K / W) (d) (m) and thermal conductivity (?) (W / m 占 K). Specifically, it is calculated by the following formula.

(2)

The thermal resistance (K / W) of the gas barrier layer

= 1 (m) / [thermal conductivity of gas barrier layer (W / mK) X 1 (m) X thickness of gas barrier layer (m)

The thickness d of the gas barrier layer is not particularly limited, but is, for example, 0.1 m to 6 m. For example, from 0.1 m to 4 m, for example, from 0.3 m to 3 m, in particular, for example, from 0.5 m to 2 m.

When the thickness of the gas barrier layer is 0.1 탆 or more, sufficient gas barrier properties can be ensured. If the thickness is 6 μm or less, the heat resistance is sufficiently high, and therefore the heat bridge through which the heat flows along the surface of the vacuum insulating material can be effectively suppressed and / or prevented, and the heat insulating ability can be improved. Further, since the workability such as flexibility is excellent, it is possible to easily adhere the joint portion of the exterior material to the vacuum insulation main body.

In the present specification, the thickness of the gas barrier layer means the maximum thickness.

As described above, the gas barrier layer of the laminate of the present invention has a Young's modulus of 100 GPa or more. Metal having a Young's modulus of 100 GPa or more is easily broken because of its hardness. Gas barrier properties of the laminate using such a metal as a gas barrier layer are likely to deteriorate due to tearing of the laminate due to bending, cracking or pinholes.

However, in the laminate of the present invention, by controlling the position of the neutral axis within the gas barrier layer, a laminate having excellent bending resistance can be obtained even when a gas barrier layer having a Young's modulus of 100 GPa or more is used.

The material of the gas barrier layer is not particularly limited as long as it has the above specific heat resistance and Young's modulus.

(Young's modulus: about 92 GPa), copper (Young's modulus: about 130 GPa), nickel (Young's modulus: about 200 GPa), SUS (Young's modulus: about 199 GPa) ), Cobalt (Young's modulus: about 209 GPa), carbon steel (Young's modulus: about 206 GPa) and / or an alloy containing these metals, or a metal such as nickel, copper, silicon oxide, alumina, , And / or an alloy vapor deposition film containing a metal thereof can be used.

Of these, a metal foil can be used because it can be easily formed into a thin film and is excellent in gas barrier property even if it is thin.

In the laminate of the present invention, the gas barrier layer may be an electrolytic metal foil. Among the metal foils, in particular, the electrolytic metal foil can be easily formed into a thin film, and even if it is thin, since the gas barrier property is excellent, the bonding portion can be easily adhered to the vacuum insulation main body. This makes it possible to provide a highly reliable vacuum insulator which is capable of effectively suppressing and / or preventing a heat bridge through which heat flows along the surface of the vacuum insulator, thereby improving the heat insulating performance and also having gas barrier property.

The method of producing the electrolytic metal foil is not particularly limited, and it is possible to apply a known electrolytic method of metal (a method of transferring metal to a rotating drum) in the same or moderately modified manner. Alternatively, a commercially available electrolytic metal foil may be used.

On the other hand, in general, a method of manufacturing a metal foil can roughly be divided into a rolling method in which an electric metal (for example, an electric copper) is rolled and annealed repeatedly to make it thin and a electrolytic method. Whether the metal foil is made by the rolling process or the electrolytic process can be identified by the following method.

That is, the metal foil produced by the rolling method has large crystal grains and is stretched in the plane direction of the foil by the rolling operation. On the other hand, the metal foil produced by the electrolytic process has crystal grains that are dense and grow in the thickness direction of the foil have. The electrolytic metal foil has a larger surface roughness than the rolled metal foil in its manufacturing process.

For example, the surface roughness Rz of the electrolytic metal foil may be 0.05 mu m to 3 mu m, for example, 0.05 mu m to 2.5 mu m, for example, 0.05 mu m to 2 mu m.

The composition of the metal foil may be any material and is not particularly limited. For example, metals such as nickel, iron, copper and the like having a Young's modulus of 100 GPa or more can be preferably used.

The metal foil may be a metal foil composed of a single metal or an alloy foil made of an alloy of two or more metals. For example, the metal foil includes nickel. That is, the metal foil may be a nickel foil or an alloy foil containing nickel.

The composition of the alloy when the metal foil is an alloy foil is not particularly limited and can be appropriately selected in consideration of a desired thermal conductivity, ease of control of the thickness of the metal foil, heat resistance, and the like. For example, when the metal foil is a nickel alloy foil (alloy foil containing nickel), nickel may be 1 wt% or more with respect to the metal foil (the total weight of the metal constituting the metal foil) % ≪ / RTI > On the other hand, the upper limit of the nickel composition is not particularly limited, but may be 50% by weight or less based on the metal foil (the total weight of the metal constituting the metal foil). With such a composition, a sufficiently low thermal conductivity and a sufficiently high thermal resistance (that is, excellent heat insulation) and a high gas barrier property can be exhibited.

The gas barrier layer is laminated on both sides thereof with a polymer layer via an adhesive layer to obtain a laminate according to the present invention. The composition of the polymer layer is not particularly limited, but usually the polymer layer (the polymer layer 6 in Fig. 1) on the inner side of the gas barrier layer (on the side where the core material or the gas adsorbent is housed) The branch may comprise a film. The polymer layer (the layer represented by (3) in FIG. 1) outside the gas barrier layer (on the side in contact with the outside air) may be a film having a surface protective effect (surface protective film). Further, a polymer layer (a layer represented by (5) in Fig. 1) which is a film having a surface protecting effect can be further provided inside the gas barrier layer.

In one embodiment, the laminate according to the present embodiment includes a first polymer layer having a Young's modulus of 5 to 100 MPa and having heat sealability, a second polymer layer having a Young's modulus of 3 to 5 GPa, 2 gas barrier layer having a Young's modulus of 100 to 300 GPa, and a third polymer layer having a Young's modulus of 1 to 3 GPa.

With this configuration, since the stress balance on the laminate can be easily obtained, the effect of the invention can be remarkably obtained.

At this time, when the laminate is used as a sheathing material, the first polymer layer may be disposed on the inner side (on the side where the core material or the gas adsorbent is accommodated).

The polymer having heat sealability which can be used as the first polymer layer (thermally fused film) is not particularly limited as long as it can be bonded by a common heat sealing method.

Examples of the material constituting the first polymer layer (thermally fused film) include low-density polyethylene, linear low density polyethylene, high density polyethylene, polyolefins such as polypropylene, ethylene-vinyl acetate copolymer, ethylene- Ethylene-acrylic acid ester copolymer, ethylene-acrylic acid ester copolymer, and polyacrylonitrile. Of these, polyethylene can be used from the viewpoint of cost, melting temperature, and laminate strength.

On the other hand, the above materials may be used singly or in combination of two or more.

In addition, the first polymer layer (thermally welded film) may be a single layer or a laminate of two or more layers. In the latter case, each layer may have the same composition or may have a different composition.

In addition, the first polymer layer (thermally welded film) may be a non-oriented film or may be stretched in one or two axes.

The thickness of the first polymer layer (thermally welded film) is not particularly limited, but may be, for example, 30 탆 to 80 탆. If it is 30 m or more, it is easy to control the neutral axis of the laminate to be located in the gas barrier layer. In addition, sufficient adhesion strength can be obtained at the time of heat sealing. When the thickness of the first polymer layer (thermally welded film) is 80 탆 or less, workability such as flexibility is excellent.

On the other hand, when the thermally welded film has a laminate structure of two or more layers, the thickness of the thermally welded film means the total thickness. In this case, the thickness of each layer may be the same or different.

The Young's modulus of the first polymer layer (thermally welded film) is not particularly limited, but may be 5 MPa to 100 MPa. When the Young's modulus is 5 MPa or more, it is easy to control so that the neutral axis of the laminate is located in the gas barrier layer. When the Young's modulus is 100 MPa or less, workability such as flexibility is excellent.

On the other hand, when the thermally welded film has a laminate structure of two or more layers, at least one thermally fusible film may have the Young's modulus, and for example, all the thermally fusible films may have the above Young's modulus.

As the second polymer layer, a polymer layer having a Young's modulus of 3 to 5 GPa can be preferably used. The gas barrier layer is sandwiched between the second polymer layer having a Young's modulus of from 3 GPa to 5 GPa and the third polymer layer (surface protective film) described later, so that the neutral axis of the laminate can be easily adjusted to be positioned in the gas barrier layer have.

Examples of the material constituting the second polymer layer include polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN) and polybutylene terephthalate (PBT), polyethylene (PE), polypropylene Polyvinylidene chloride (PVC), polyvinylidene chloride (PVDC), ethylene vinyl alcohol copolymer (EVOH), polyvinyl alcohol resin (PVA), and polyvinyl alcohol resin (PVA) But are not limited to, polycarbonate (PC), polyethersulfone (PES), polymethyl methacrylate (PMMA), and polyacrylonitrile resin (PAN). Among them, polyethylene terephthalate (PET) or ethylene vinyl alcohol copolymer (EVOH) is preferably used from the viewpoints of cost and gas barrier property.

These films may contain various well-known additives and stabilizers such as an antistatic agent, an ultraviolet ray inhibitor, a plasticizer, a lubricant, and the like.

On the other hand, the above materials may be used singly or in combination of two or more.

The second polymer layer may be a single layer or a laminate of two or more layers. In the latter case, each layer may have the same composition or may have a different composition.

In addition, the second polymer layer may be a film that is not lead-free or may be uniaxially or biaxially stretched, but it may be a stretched film. By stretching, the strength is increased and the Young's modulus is increased. In addition, a thin film can be formed and the workability can be improved.

The thickness of the second polymer layer is not particularly limited, but may be in the range of 10 [mu] m to 30 [mu] m. In the above range, it is easy to balance stress acting on the laminate, and it is easy to control so that the neutral axis of the laminate is located in the gas barrier layer. It is also excellent in workability such as flexibility.

On the other hand, when the second polymer layer has a laminate structure of two or more layers, the thickness of the layer means the total thickness. In this case, the thickness of each layer may be the same or different.

On the other hand, when the second polymer layer has a laminate structure of two or more layers, at least one layer may have the above Young's modulus, and all layers may have the above Young's modulus.

The third polymer layer (surface protective film) is not particularly limited, and a material commonly used as a surface protective film of a facing material can be used. Examples of the material constituting the surface protective film include polyamide (nylon) (PA) such as nylon-6 and nylon-66, which have high sticking properties from the viewpoint of suppressing rupture of the outer material.

These films may contain various additives and stabilizers well known in the art, such as antistatic agents, ultraviolet ray inhibitors, plasticizers, lubricants and the like. On the other hand, the above materials may be used alone or in a mixture of two or more.

The surface protective film may be a single layer or a laminate of two or more layers. In the latter case, each layer may have the same composition or different compositions.

The third polymer layer may be a non-stretched film or may be uniaxially or biaxially stretched, but it may be a stretched film. When stretched, the strength is increased, and the Young's modulus is increased. Further, it can be made into a thin film, and the workability can be improved. In addition, the effect of protecting against piercing can be enhanced.

The thickness of the third polymer layer (surface protective film) is not particularly limited and may be the same as a known thickness. For example, the thickness of the surface protective film may range from 10 [mu] m to 30 [mu] m. When the thickness is 10 m or more, the protective effect of the gas barrier layer is sufficiently obtained, and cracks and the like are less likely to occur. If it is 30 μm or less, the workability such as flexibility is excellent.

On the other hand, when the third polymer layer (surface protective film) has a laminated structure of two or more layers, the thickness of the layer means the total thickness. In this case, the thicknesses of the respective layers may be the same or different.

The Young's modulus of the third polymer layer (surface protective film) is not particularly limited, but is preferably 1 GPa to 3 GPa. When the Young's modulus is 1 GPa or more, it is easy to control the neutral axis of the laminate to be located in the gas barrier layer. When the Young's modulus is 3 GPa or less, workability such as flexibility is excellent.

On the other hand, when the third polymer layer (surface protective film) has a laminated structure of two or more layers, it is preferable that at least one surface protective film has the above-mentioned Young's modulus, and all the surface protective films have the above- good.

An adhesive layer is provided between the polymer layer and the gas barrier layer and between the respective polymer layers. The adhesive layer allows the polymer layer and the gas barrier layer or the polymer layers to adhere to each other.

The adhesive that can be used for the adhesive layer is not particularly limited, and examples thereof include urethane-based adhesives, polyacrylate ester-based adhesives, cyanoacrylate-based adhesives, and silicone-based adhesives. Particularly, a urethane-based adhesive can be used, and more preferably, a two-part curing type isocyanate adhesive using a mixture of a reagent (polyol) as a main component and a curing agent (polyisocyanate) can be used. When a urethane-based adhesive is used, pinholes hardly occur even if distortion processing is performed, and the heat insulating effect of the vacuum insulating material can be maintained for a long period of time.

The adhesives usable in the respective adhesive layers may be the same or different.

The Young's modulus of the adhesive layer is not particularly limited, but is preferably 10 MPa or less from the viewpoint of facilitating control of the position of the neutral axis of the laminate.

The thickness of the adhesive layer is not particularly limited, but may be, for example, in the range of 1 μm to 5 μm. Within this range, it is easy to control the neutral axis of the laminate to be located in the gas barrier layer. The thickness of each adhesive layer may be the same or different.

The thickness of the laminate is not particularly limited.

Specifically, the thickness of the laminate is, for example, in the range of 40 μm to 210 μm.

When a laminate having such a thickness as described above is used, the heat bridge can be effectively suppressed / prevented to improve the heat insulating performance, and also the gas barrier property and the workability are excellent.

The laminate according to the present invention is preferably excellent in gas barrier properties. Specifically, the water vapor transmission rate of the laminate ^{1 × 10 -3 (g / m} 2 · day) or less may be, more preferably not more than ^{5 × 10 -4 (g / m} 2 · day).

If less than the water vapor transmission rate of the laminate ^{1 × 10 -3 (g / m} 2 · day), it can maintain long-term the degree of vacuum inside the vacuum heat insulating material used as the exterior material.

On the other hand, because the water vapor transmission rate of the laminate is, the lower preferred lower limit is not particularly limited, it is usually sufficient, 1 × 10 ^-7 if (g / m ² · day) or more.

In addition, it is the water vapor permeability after the bending is more preferably less than or equal ^{to, 1 × 10 -3 (g /} m 2 · day) ^{is, 5 × 10 -4 (g /} m 2 · day) , and preferably less.

In the present specification, the water vapor permeability of the laminate and the water vapor permeability after folding of the laminate are measured by the method described in the following examples.

It is preferable that the laminate according to the present invention has a low thermal conductivity in consideration of heat insulation. It is also preferable that the vacuum insulation material using this laminate as the exterior material has a low thermal conductivity.

Specifically, the thermal conductivity (?) Of the vacuum insulator (exterior material) is preferably 0.01 W / mK or less, more preferably 0.005 W / mK or less. With such a thermal conductivity, the vacuum insulation material is excellent in heat insulation.

On the other hand, since the thermal conductivity of the vacuum heat insulator (exterior material) is preferably as low as possible, the lower limit is not particularly limited, but usually 0.0005 W / m · K or more is sufficient.

The thermal conductivity of the vacuum insulating material (outer material) can be measured by a known measuring method. In the present specification, the thermal conductivity of the vacuum insulating material can be measured by the method described in the following examples.

The difference in thermal conductivity of the vacuum insulator before and after the accelerated deterioration test is preferably 10 mW / mK or less, more preferably 5 mW / mK or less, still more preferably 2 mW / mK or less , Particularly preferably 1.5 mW / m · K or less.

In the present specification, the difference in thermal conductivity of the vacuum insulator before and after the accelerated deterioration test of the vacuum insulator can be measured by the method described in the following examples.

The method of manufacturing the vacuum insulator is not particularly limited, and a method similar to the public knowledge or a method modified appropriately to known methods can be used. For example, (i) two laminated bodies are prepared, one laminate (laminated film) is folded back, and the thermally fused films positioned at the ends of the laminated body facing each other are thermally welded to form a bag- (Ii) a method in which a core material and a gas adsorbent are inserted into the external material and the thermally fused films positioned at the openings of the bag-shaped laminate film are thermally fused under reduced pressure; (ii) A laminated body (laminate film) is disposed on the laminated body, heat-welding the thermally fused films positioned at the ends of the respective laminated bodies to obtain a bag-shaped exterior material, inserting the core material and the gas absorbent into the bag- And a method of thermally fusing the thermally fused films located in the vicinity of the openings of the bag-shaped laminated film under reduced pressure.

(Core material)

The core material usable in the present invention becomes the skeleton of the vacuum insulator and forms a vacuum space. Here, the material of the core material is not particularly limited, and a known core material can be used. For example, inorganic fibers such as glass wool, rock wool, alumina fibers, and metal fibers made of a metal having a low thermal conductivity; Synthetic fibers such as polyester, polyamide, acrylic, and polyolefin; natural fibers such as cellulose, cotton, hemp, wool, and silk produced from wood pulp; regenerated fibers such as rayon; and semi-synthetic fibers such as acetate And the like.

The material of the core material may be used alone, or may be a mixture of two or more. Of these, glass wool can be used. The core material made of these materials has high elasticity of the fiber itself, low thermal conductivity of the fiber itself, and low industrial cost.

(Gas adsorbent)

The gas adsorbent usable in the present invention adsorbs water vapor or air (oxygen, nitrogen) remaining or entering the sealed space of the vacuum insulator. Here, the gas adsorbent is not particularly limited, and a known gas adsorbent may be used.

For example, it is possible to use chemically adsorbed substances such as calcium oxide (calcium oxide) and magnesium oxide, physically adsorbed substances such as zeolite, communicating urethane, lithium compounds, copper ion-exchanged ZSM-5 type zeolite possessing chemical adsorption and physical adsorption properties, Rushib 13X, and the like.

The core material material may be used alone, or a mixture of two or more thereof.

As described above, the laminate of the present invention can effectively suppress the generation of heat bridges, is excellent in workability, and suppresses occurrence of pinholes and cracks.

Therefore, the vacuum insulation material using the laminate of the present invention as the exterior material is suitable for devices requiring maintenance of heat insulation performance such as freezers, refrigerators, vending machines, hot water containers, insulation materials for buildings, automotive insulation materials, Can be applied.

(Example)

The effects of the present invention will be described with reference to the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following embodiments. On the other hand, in the following examples, unless otherwise noted, the operation was carried out at room temperature (25 캜). In addition, unless otherwise specified, "%" and "part" mean "% by weight" and "part by weight", respectively.

Example 1

(Thickness: 25 占 퐉; Young's modulus: 1.4 GPa) as a third polymer layer, a nickel electrolytic foil (thickness: 1 占 퐉; (Thickness: 12 占 퐉; Young's modulus: 4 GPa) as a first polymer layer, a linear low-density polyethylene film (thickness: 50 占 퐉 ; Young's modulus: 10 MPa), and each layer was laminated with a dry laminate through a two-liquid curing type isocyanate adhesive (thickness: 3 m; Young's modulus: 3.1 MPa) as an adhesive layer to obtain laminate 1.

A laminated body of short fiberglass was used as a core material, and a burnt lime contained in a breathable outer covering material was used as a gas adsorbent. Using these laminate 1, core material and gas adsorbent, a vacuum insulation material 1 having a width of 290 mm, a depth of 410 mm and a height of 12 mm was produced.

Example 2

In the same manner as in Example 1 except that the thickness of the nickel electrolytic foil was changed to 3 mu m, the laminate 2 and the vacuum insulator 2 were produced.

Example 3

In the same manner as in Example 1 except that the biaxially oriented ethylene vinyl alcohol copolymer was changed to biaxially oriented polyethylene terephthalate (thickness: 12 m; Young's modulus: 3.4 GPa) as the second polymer layer, Insulating material 3 was produced.

Example 4

In the same manner as in Example 3 except that the thickness of the nickel electrolytic foil was changed to 3 mu m, the laminate 4 and the vacuum insulator 4 were produced.

Comparative Example 1

(Thickness: 25 占 퐉; Young's modulus: 1.4 GPa), biaxially oriented polyethylene terephthalate (thickness: 12 占 퐉; Young's modulus: 3.4 GPa) in the order from the upper surface to the lower surface, (Thickness: 7 μm; heat resistance: 602 K / W; Young's modulus: 69 GPa) and a linear low density polyethylene film (thickness: 50 μm; Young's modulus: 10 MPa) were used as the gas barrier layer And vacuum insulator 5 were produced.

Comparative Example 2

(Thickness: 25 占 퐉; Young's modulus: 1.4 GPa), biaxially stretched polyethylene terephthalate (thickness: 12 占 퐉; Young's modulus: 3.4 GPa), and the like were prepared in the same manner as in Example 3, Laminated body 6 and vacuum insulator 6 were produced in the same manner as in Example 1 except that the film was made of VM-PET (thickness: 12 占 퐉) and a linear low-density polyethylene film (thickness: 50 占 퐉;

Here, as the VM-PET, an Al vapor deposition film having a thickness of 30 nm formed on polyethylene terephthalate having a thickness of 12 탆 was used, and an Al vapor deposition film was laminated on the biaxially oriented polyethylene terephthalate side.

Comparative Example 3

(Thickness: 12 占 퐉; Young's modulus: 3.4 GPa), biaxially stretched nylon (thickness: 25 占 퐉; Young's modulus: 1.4 GPa), and biaxially oriented polyethylene terephthalate Except that a nickel electrolytic foil (thickness: 1 m; thermal resistance: 11,173 K / W; Young's modulus: 200 GPa) and a linear low density polyethylene film (thickness: 50 m; Young's modulus: 10 MPa) were used as a gas barrier layer. 7 and a vacuum insulator 7 were produced.

The laminated bodies 1 to 7 and the vacuum heat insulators 1 to 7 prepared above were subjected to the following evaluations.

<Evaluation 1: Position of neutral axis>

The positions of neutral axes of the laminate materials 1 to 7 produced in Examples 1 to 4 and Comparative Examples 1 to 3 were calculated using the following formula. The position of the neutral axis is indicated by the distance (μm) from the surface protective film side (upper side).

(1)

Here, y is the distance to the neutral axis from the upper surface of the compression side during bending (μm), Ei is i Young's modulus of the second layer (Pa), Si is i sectional first moment (μm ³⁾ of the second layer, Ai is i-th layer (Μm ³ ). The results are shown in Table 1 below.

On the other hand, the folding and compression was carried out by folding the laminate so that the surface of the laminate was in contact with the upper surface (the biaxially oriented nylon side) of the laminate, and then folding the laminate once and then bending it to the opposite side.

&Lt; Evaluation 2: Vapor permeability before and after bending >

The laminate 1 to 7 prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were measured for water vapor permeability (g / m ²占 day) before and after bending according to the following method.

On the other hand, the bending angle means that the sample measured before bending is cross-bent.

The water vapor transmission rate was measured using aquatran (manufactured by MOCON) according to ISO15106-3 at a temperature of 40 DEG C and a relative humidity of 90% RH.

The results are shown in Table 1 below.

<Evaluation 3: Thermal Conductivity and Thermal Resistance of Gas Barrier Layer>

The gas diffusion layers (metal portions) used in Examples 1 to 4 and Comparative Examples 1 to 3 were measured for thermal diffusivity in the in-plane direction using a Thermowave Analyzer (manufactured by Ilsan Kogyo Co., Ltd.) From the density, the thermal conductivity (W / m · K) was calculated. The thermal resistance (K / W) was calculated from the obtained thermal conductivity and thickness.

The results are shown in Table 1 below.

<Evaluation 4: Thermal Insulation Property Maintenance of Vacuum Insulation>

The thermal conductivity (mW / cm 2) of the vacuum insulators 1 to 7 prepared in Examples 1 to 4 and Comparative Examples 1 to 3 after HFM 436 (manufactured by NETZSCH Co., Ltd.) m 占 K) were measured, and the heat insulating performance was compared based on the difference. The results are shown in Table 1 below.

<Evaluation 5: Heat bridge performance of vacuum insulation>

For the vacuum insulation materials 1 to 7 prepared in Examples 1 to 4 and Comparative Examples 1 to 3, two vacuum insulators were inserted from both sides using a heat flow meter HFM 436 (manufactured by NETZSCH), and two The heat conduction rate (mW / m · K) was measured by arranging the vacuum insulation material against the surface to compare the heat bridge performance. The results are shown in Table 1 below.

The neutral axis
location Water vapor permeability of the laminate
(g / m ² day) The thermal conductivity of the gas barrier layer
(W / mK) Thermal resistance of the gas barrier layer
(K / W) Difference in thermal conductivity of vacuum insulation
(mW / mK) Heat-bridge performance of vacuum insulation
(mW / mK) Before fold After folding Example 1 28.2 탆 (in nickel) <5 × 10 ^-4 <5 × 10 ^-4 89.5 11,173 1.3 2.2 Example 2 28.5 占 퐉 (in nickel) <5 × 10 ^-4 <5 × 10 ^-4 89.5 3,724 1.2 2.6 Example 3 29.4 占 퐉 (in nickel) <5 × 10 ^-4 <5 × 10 ^-4 89.5 11,173 1.3 2.1 Example 4 29.5 占 퐉 (in nickel) <5 × 10 ^-4 <5 × 10 ^-4 89.5 3,724 1.3 2.7 Comparative Example 1 43.2 탆 (in aluminum) <5 × 10 ^-4 <5 × 10 ^-4 237 602 1.2 3.6 Comparative Example 2 35.0 占 퐉 (in polyethylene terephthalate) 4.2 x 10 ^-2 9.1 x 10 ^-1 237 42,194 15.9 2.0 Comparative Example 3 34.3 탆 (in nylon) <5 × 10 ^-4 5.5 × 10 ^-2 89.5 11,173 11.7 2.2

As shown in Table 1, the laminate of Examples 1 to 4, in which the gas barrier layer possessing a predetermined thermal resistance and Young's modulus and the mechanical neutral axis of the laminate is located in the gas barrier layer, The effect of suppressing the influence of the heat bridge is higher than that of the laminate of Comparative Example 1 in which the thermal resistance is less than 650 K / W.

Compared with the laminate of Comparative Examples 2 and 3 in which the position of the mechanical neutral axis is located in a layer other than the gas barrier layer, the laminated body exhibits excellent gas barrier properties equivalent to those before bending and exhibits high durability (bending resistance) okay.

One… Vacuum insulation,
2… The laminate,
3, 5, 6 ... Polymer layer,
4… Gas barrier layer,
7 ... Core material,
8… Gas adsorbent,
9 ... The joint portion (seal portion)
11, 15, 17 ... Polymer layer,
12, 14, 16 ... Adhesive layer,
13 ... Gas barrier layer.

Claims (10)

A laminate comprising at least one polymer layer, a gas barrier layer, and at least one polymer layer in this order,
Wherein the gas barrier layer has a thermal resistance of 650 K / W or more and a Young's modulus of 100 GPa or more,
Wherein a position of a neutral axis represented by the following formula is located in the gas barrier layer:
(1)

Ei is the Young's modulus of the i-th layer, Si is the first moment of area of the i-th layer, Ai is the cross-sectional area of the i-th layer, , n is the number of layers constituting the laminate, and is an integer of 5 or more. The laminate according to claim 1, wherein the gas barrier layer is composed of a metal foil. The laminate according to claim 2, wherein the metal foil is an electrolytic metal foil. The laminate according to claim 2 or 3, wherein the metal foil has a thickness of 0.1 mu m to 6 mu m. The laminate according to any one of claims 2 to 4, wherein the metal foil is a nickel foil. The laminate according to any one of claims 1 to 5, wherein the laminate has a first polymer layer having an adhesive layer interposed between the layers, at least a Young's modulus of 5 MPa to 100 MPa and heat sealability, a Young's modulus of 3 GPa to 5 GPa A gas barrier layer having a Young's modulus of 100 GPa to 300 GPa, and a third polymer layer having Young's modulus of 1 GPa to 3 GPa are laminated in this order. The laminate according to claim 6, wherein the first polymer layer comprises polyethylene. The laminate according to claim 6 or 7, wherein the second polymer layer comprises a polyethylene terephthalate or an ethylene vinyl alcohol copolymer. 9. The laminate according to any one of claims 6 to 8, wherein the third polymer layer comprises nylon. Claims: 1. A vacuum insulator obtained by enclosing a core material and a gas adsorbent with an exterior material having a pair of gas barrier properties so as to be sandwiched therebetween from both sides, Wherein at least one of the materials is a laminate according to any one of claims 1 to 9.

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