JP2014035007A - Laminate for vacuum heat insulation material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate for vacuum heat insulation material which has no defective quality such as defective appearance due to "heat shrinkage wrinkle" and "slack" and defective oxygen gas barrier property, and has a heat insulation performance being by no means inferior as compared to an ethylene-vinyl alcohol copolymer film layer, and to provide a vacuum heat insulation material using the laminate for vacuum heat insulation material at a low cost.SOLUTION: The laminate for vacuum heat insulation material which is used for vacuum heat insulation material made by enclosing heat insulation core material with jacketing wrapping material made of a laminated body and degassing an internal part enclosed by the jacketing wrapping material to make a vacuum state is produced by laminating a base layer, a water vapor gas barrier layer, an oxygen gas barrier layer and a heat adhesive resin layer in order. Therein, the oxygen gas barrier layer is made of a three-layer co-extrusion film (nylon/ethylene-vinyl alcohol copolymer/nylon) which is subjected to aluminum deposition on one-side surface thereof and is biaxially stretched.

Description

  The present invention relates to a laminate for a vacuum heat insulating material and a vacuum heat insulating material using the same, and more specifically, heat insulation used for a refrigerator, a heat storage, a water heater, a vending machine, a transport container, a system bath, a housing wall, and the like. The present invention relates to a laminate for a vacuum heat insulating material used for a wall or a heat insulating wall used around a heating element such as a car, an airplane, a ship, a train, and an OA device, and a vacuum heat insulating material used therefor.

  Conventionally, vacuum heat insulating materials have been used as heat insulating layers in refrigerators, water heaters, vending machines, and the like. Such a vacuum heat insulating material is usually packaged in a sealed state by encapsulating a heat insulating core material in the outer covering material, degassing the inside of the outer covering material and thermally bonding in a vacuum state. Yes.

  In order to maintain the heat insulating performance of the vacuum heat insulating material for a long period of time, it is necessary to maintain the inside of the outer covering material in a vacuum state for a long period of time. Therefore, the laminated body for vacuum heat insulating material used for the envelope material has excellent gas barrier property for preventing gas from permeating from the outside, and heat bonding for covering and sealing the heat insulating core material. Various functions such as sex are required. Therefore, the laminate for a vacuum heat insulating material is usually configured as a laminate in which a plurality of films having these various functions are laminated.

  Specifically, an outermost layer composed of a biaxially oriented polypropylene layer or a polyamide layer, a second layer composed of a polyethylene terephthalate resin layer deposited with aluminum, an ethylene vinyl alcohol copolymer film layer deposited with aluminum, a linear low density An outer packaging material in which a welding layer made of a polyethylene resin layer or a high-density polyethylene resin layer is sequentially laminated is used (for example, see Patent Document 1).

  The technique disclosed in Patent Document 1 can be used as an outer packaging material that can improve heat insulation performance, and can provide a vacuum heat insulating material that ensures reliability. The vinyl alcohol copolymer film layer is subject to heat shrinkage and sagging due to heat shrinkage of the ethylene vinyl alcohol copolymer film during aluminum deposition, and problems caused by this. In the laminating process when making the outer packaging material, the “heat shrinkage wrinkles” remain wrinkle marks and the “sagging” becomes broken wrinkles, both of which have poor appearance such as poor appearance and oxygen gas barrier property. At the same time, it is necessary to remove defective parts, resulting in deterioration of productivity and the resulting high cost. It has been a problem.

JP 2012-47210 A

  Therefore, the present invention is free from quality defects such as poor appearance due to “heat shrinkage wrinkles” and “sagging” and oxygen gas barrier properties, and heat insulation performance comparable to that of an ethylene vinyl alcohol copolymer film layer deposited with aluminum. It is providing the laminated body for vacuum heat insulating materials which has these, and a vacuum heat insulating material using the same at low cost.

  In order to achieve the above-mentioned object, the inventor of the present invention described in claim 1 encloses a heat insulating core material with an outer envelope material made of a laminate, and removes the interior enclosed with the outer envelope material. In a laminate for a vacuum heat insulating material used for a vacuum heat insulating material that is brought into a vacuum state by vaporization, a base material layer, a water vapor gas barrier layer, an oxygen gas barrier layer, and a heat-adhesive resin layer are sequentially laminated, and the oxygen gas barrier layer is It is characterized by comprising a biaxially stretched three-layer coextruded film (nylon / ethylene-vinyl alcohol copolymer / nylon) with aluminum vapor deposition on one surface.

  Moreover, the present invention according to claim 2 is that in the laminate for a vacuum heat insulating material according to claim 1, the water vapor gas barrier layer is a biaxially stretched polyester film in which a vapor deposition layer of an inorganic substance or a metal oxide is formed. It is a feature.

  Moreover, the present invention according to claim 3 is the laminate for a vacuum heat insulating material according to claim 2, wherein the vapor deposition layer of the water vapor gas barrier layer and the vapor deposition layer of the oxygen gas barrier layer are opposed to each other via an adhesive layer. It is characterized by this.

  Moreover, the vacuum heat insulating material of this invention of Claim 4 encloses the heat insulation core material in the outer covering material using the laminated body for vacuum heat insulating materials in any one of Claims 1-3, The inside of the outer covering material is deaerated and hermetically packaged in a vacuum state.

  According to the present invention, it is possible to eliminate quality defects such as poor appearance and oxygen gas barrier property caused by using an ethylene vinyl alcohol copolymer film deposited with aluminum in a conventional laminate for vacuum heat insulating material, In the heat insulation performance, there is an effect that it is possible to provide a vacuum heat insulating material laminate having a performance equal to or higher than that of a conventional vacuum heat insulating material laminate and a vacuum heat insulating material using the same. .

It is a figure which shows the layer structure of one Example of the laminated body for vacuum heat insulating materials concerning this invention schematically. It is sectional drawing which shows schematically one Example of the vacuum heat insulating material concerning this invention.

The above-described present invention will be described in detail below with reference to the drawings.
FIG. 1 is a diagram schematically showing a layer configuration of one embodiment of a laminate for a vacuum heat insulating material according to the present invention, and FIG. 2 is a cross-sectional view schematically showing one embodiment of a vacuum heat insulating material according to the present invention. In the figure, 1 is a laminate for a vacuum heat insulating material, 1 'is an outer covering material, 2 is a vacuum heat insulating material, 11 is a base material layer, 12 is a water vapor gas barrier layer, 13 is an oxygen gas barrier layer, and 14 is a thermal adhesive property. A resin layer, 20 is a heat insulating core material, and A is a thermal bonding part.

  FIG. 1 is a diagram schematically showing a layer configuration of one embodiment of a laminate for a vacuum heat insulating material according to the present invention. The laminate for a vacuum heat insulating material 1 includes a base material layer 11, a water vapor gas barrier layer 12, an oxygen gas barrier. The layer 13 and the thermoadhesive resin layer 14 are laminated in order.

  First, the base material layer 11 will be described. Since the base material layer 11 is a basic material constituting a laminate for a vacuum heat insulating material, a plastic film made of a synthetic resin having excellent properties in mechanical, physical, chemical and the like can be used. For example, a film made of a resin such as polyester, polyamide, polypropylene, polycarbonate, or polyacetal can be used. As these plastic films, any of an unstretched film or a stretched film stretched in a uniaxial direction or a biaxial direction can be used, but a biaxially stretched film is preferable in terms of mechanical and physical superiority. . The thickness of the base material layer 11 is suitably 9 to 30 μm.

  In FIG. 1, the base material layer 11 is an outer layer so as to be positioned on one outer surface of the laminate 1 for vacuum heat insulating material, and is shown as a single layer configuration. The base material layer 11 may be further provided between the water vapor gas barrier layer 12 and the oxygen gas barrier layer or between the oxygen gas barrier layer and the thermal adhesive resin layer 14 as necessary. It is good also as a structure to interpose.

  Next, the water vapor gas barrier layer 12 will be described. Examples of the water vapor gas barrier layer 12 include a plastic film on which a metal typified by aluminum is vapor-deposited, a plastic film on which an inorganic material typified by silicon oxide and a metal oxide typified by aluminum oxide are vapor-deposited, or a typical polyvinylidene chloride. A plastic film coated with a water vapor gas barrier composition or a polyvinylidene chloride film can be used. In particular, there is little deterioration over time, there are few cracks even when bent, and when the laminate for vacuum heat insulating material is used as the outer covering material of the vacuum heat insulating material, the thermal conductivity through the outer covering material is A plastic film on which an inorganic material typified by silicon oxide is vapor-deposited is suitable as a material that is small and can provide sufficient heat insulation performance. Furthermore, what laminated | stacked one or more vapor deposition layers which consist of the carbon containing silicon oxide formed by the plasma chemical vapor deposition method on the plastic film as a base material is used more preferably.

  The plastic film constituting the water vapor gas barrier layer 12 is excellent in processability for imparting water vapor gas barrier properties and can be favorably retained without impairing the water vapor gas barrier properties. It is required to be excellent in various physical properties such as processability and heat resistance at the time of making a bag as a packaging material, and any material that satisfies these requirements may be used. For example, those described as the base material layer 11 are used. Of these, polyester-based, polyamide-based, and polypropylene-based plastic films are particularly preferable, and a thickness of 9 to 30 μm is appropriate.

Next, the oxygen gas barrier layer 13 will be described. As the oxygen gas barrier layer 13, a plastic film on which a metal typified by aluminum is deposited, a plastic film on which an inorganic material typified by silicon oxide or a metal oxide typified by aluminum oxide is deposited, or polyvinyl alcohol or polychlorinated Oxygen gas barrier such as plastic film coated with oxygen gas barrier composition represented by vinylidene, polyvinylidene chloride film, ethylene-vinyl alcohol copolymer (EVOH) film, MXD nylon film [manufactured by Toyobo Co., Ltd.] However, in the oxygen gas barrier property, the oxygen gas permeability is 1.0 ml / m ² · day · MPa or less, and an aluminum oxide-deposited EVOH film having a thickness of 12 μm is used. 0ml / m ² · Biaxially stretched three-layer coextruded film (5.5 μm thick polyamide layer / 4.0 μm thick EVOH layer / 5.5 μm thick polyamide) subjected to aluminum vapor deposition and has performance equivalent to ay · MPa Layer) can be preferably used.

  The biaxially stretched three-layer coextruded film with aluminum vapor deposition has no "heat shrinkage wrinkles" or "sagging" compared to the 12 μm thick EVOH film with aluminum vapor deposition, and has excellent processability and appearance. There is no quality defect such as a defect or oxygen gas barrier property defect, and a very good laminate for a vacuum heat insulating material can be obtained in terms of yield and quality stability.

  Next, the thermal adhesive resin layer 14 will be described. The heat-adhesive resin layer 14 may be any thermoplastic resin that can be melted by heat and fused to each other. For example, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear ( Linear) low-density polyethylene, ethylene-vinyl acetate copolymer, acid copolymer of ethylene and acrylic acid, ester copolymer of ethylene and acrylic acid ester, etc., polypropylene, ethylene-propylene copolymer, A methylpentene polymer or the like can be used. The thickness of the adhesive resin layer 14 may be 10 μm or more, and may be determined in consideration of required physical properties and costs.

  In addition, as a method of laminating each layer for forming the laminate 1 for a vacuum heat insulating material, a known laminating method using an adhesive layer made of an adhesive or a melt-extruded resin such as a dry lamination method and a sandwich lamination method is appropriately used. What is necessary is just to laminate | stack. In any of the lamination methods, the necessary surface is subjected to corona discharge treatment, plasma treatment, anchor agent coating treatment, etc., or any easy adhesion treatment as necessary, and the adhesion strength between the layers. It is natural to secure this.

  In the case where a plastic film on which vapor deposition of a metal, an inorganic substance, a metal oxide or the like is used for the water vapor gas barrier layer 12, the vapor deposition surfaces of the water vapor gas barrier layer 12 and the oxygen gas barrier layer 13 are opposed to each other via an adhesive layer. It is preferable to adopt a configuration to do so. By configuring in this manner, pinholes in the vapor deposition layer and variations in vapor deposition can be complemented to prevent the barrier performance from being deteriorated, and the vapor deposition layer has the effect of making it difficult to receive external damage. is there.

  FIG. 2 is a cross-sectional view schematically showing an embodiment of the vacuum heat insulating material according to the present invention. The vacuum heat insulating material 2 is heat-insulated in the envelope material 1 ′ using the laminate 1 for vacuum heat insulating material. The core material 20 is enclosed, and the inside of the outer covering material 1 ′ is deaerated to be in a vacuum state. The said vacuum heat insulating material 2 can be manufactured as follows, for example. That is, a pair of rectangular laminates for vacuum heat insulating material 1 are stacked with the heat-adhesive resin layer 14 facing each other, and thermally bonded to form a heat-bonding portion A on the three peripheral edges. The outer covering material 1 ′ is made in a bag, and after the heat insulating core material 20 is received from the opening of the outer covering material 1 ′, the inside of the outer covering material 1 ′ is evacuated to a vacuum state, By thermally bonding the opening in the state, the vacuum heat insulating material 2 made of a four-side seal type packaging bag can be obtained. The form of the packaging bag is not limited to the four-side seal type, but is a three-side seal type, and can be an appropriate form such as a gusset type or a pillow type.

  As the heat insulating core material 20, an inorganic material such as silica, pearlite, calcium silicate, or an organic material such as polyurethane foam is used. Further, examples of the form of the heat insulating core material 20 include fine powder, porous material, and fibrous material.

  The inside of the vacuum heat insulating material 2 is normally in a vacuum state of 5 Pa or less, and is configured so that heat conduction by convection is minimized. If the degree of vacuum is higher than 5 Pa, the air remaining inside convects and the heat insulation performance deteriorates, which is not preferable.

Hereinafter, the present invention will be described in more detail with reference to examples.
[Example 1]
A 12 μm-thick biaxially stretched polyethylene terephthalate film (hereinafter, referred to as “ON15”) having a silicon oxide vapor-deposited layer on one surface via an adhesive on the corona discharge treated surface of a 15 μm-thick biaxially stretched polyamide film (hereinafter referred to as ON15). The other surface (abbreviated as PET12) (corona discharge treatment surface) is laminated, and then 15 μm thick biaxially stretched with an aluminum vapor deposition layer on one surface via an adhesive on the silicon oxide vapor deposition surface of the PET12. Three-layer coextruded film (5.5 μm thick polyamide layer / 4.0 μm thick EVOH layer / 5.5 μm thick polyamide layer) (hereinafter referred to as ON5.5 // EVOH4.0 // ON5.5) And a non-stretched polypropylene having a thickness of 30 μm via an adhesive on the other surface (corona discharge treated surface) of the three-layer coextruded film. Down film to obtain a laminate of the present invention by laminating a corona discharge treated surface (hereinafter, abbreviated as cpp30).
Laminate structure: ON15 / adhesive / PET12 / silicon oxide vapor deposition layer / adhesive / aluminum vapor deposition layer / ON5.5 // EVOH4.0 // ON5.5 / adhesive / CPP30
(// indication indicates the laminated part by coextrusion method)

[Example 2]
A 12 μm-thick biaxially stretched polyethylene terephthalate film (hereinafter, referred to as a 20 μm thick biaxially stretched polypropylene film (hereinafter abbreviated as OPP20) having a silicon oxide vapor-deposited layer on one surface via an adhesive on the corona discharge treated surface. The other surface (abbreviated as PET12) (corona discharge treatment surface) is laminated, and then 15 μm thick biaxially stretched with an aluminum vapor deposition layer on one surface via an adhesive on the silicon oxide vapor deposition surface of the PET12. Three-layer coextruded film (5.5 μm thick polyamide layer / 4.0 μm thick EVOH layer / 5.5 μm thick polyamide layer) (hereinafter referred to as ON5.5 // EVOH4.0 // ON5.5) And a vapor deposition layer surface of the three-layer coextruded film, and then the other surface (corona discharge treatment surface) of the three-layer coextruded film with an unstretched high density of 50 μm thickness through an adhesive. Polyethylene film to obtain a laminate of the present invention by laminating a corona discharge treated surface (hereinafter, abbreviated as HDPE50).
Laminate structure: OPP20 / adhesive / PET12 / silicon oxide vapor deposition layer / adhesive / aluminum vapor deposition layer / ON5.5 // EVOH4.0 // ON5.5 / adhesive / HDPE50
(// indication indicates the laminated part by coextrusion method)

[Comparative Example 1]
A 12 μm-thick biaxially stretched polyethylene terephthalate film (hereinafter, referred to as a 25 μm thick biaxially stretched polyamide film (hereinafter abbreviated as ON25) having a silicon oxide vapor-deposited layer on one surface via an adhesive on the corona discharge treated surface. 15 μm thick ethylene-vinyl alcohol copolymer film (hereinafter referred to as “PET12”) having an aluminum vapor deposition layer on one side of the PET 12 with an adhesive layer on the silicon oxide vapor deposition surface. , EVOH15) and a corona of an unstretched polypropylene film (hereinafter abbreviated as CPP30) having a thickness of 30 μm via an adhesive on the other surface (corona discharge treated surface) of the EVOH15. A discharge body was laminated to obtain a laminate as a comparative example.
Laminate structure: ON15 / adhesive / PET12 / silicon oxide vapor deposition layer / adhesive / aluminum vapor deposition layer / EVOH15 / adhesive / CPP30

[Comparative Example 2]
A 12 μm-thick biaxially stretched polyethylene terephthalate film (hereinafter, referred to as a 20 μm thick biaxially stretched polypropylene film (hereinafter abbreviated as OPP20) having a silicon oxide vapor-deposited layer on one surface via an adhesive on the corona discharge treated surface. The other surface (corona discharge treated surface) of PET12 is laminated, and then a 15 μm-thick biaxially stretched polyamide film (hereinafter abbreviated as ON15) is bonded to the silicon oxide deposition surface of PET12 via an adhesive. A 12 μm-thick ethylene-vinyl alcohol copolymer film (hereinafter referred to as “on”) having one corona discharge treatment surface laminated, and then having an aluminum vapor deposition layer on one surface through an adhesive on the other corona discharge treatment surface of the ON15. , EVOH12 is abbreviated as one surface (aluminum deposition layer surface), and then the other surface of the EVOH12 (corona discharge) Unstretched high density polyethylene film 50μm thick over the adhesive to bedding plane) (hereinafter, to obtain a laminate of the comparative example by laminating a corona discharge treated surface of the abbreviated HDPE50).
Laminate structure: OPP20 / adhesive / PET12 / silicon oxide vapor deposition layer / adhesive / ON15 / adhesive / aluminum vapor deposition layer / EVOH12 / adhesive / HDPE50

  Examples 1 and 2 are configurations that do not use the “ethylene vinyl alcohol copolymer film layer deposited with aluminum” used in Comparative Examples 1 and 2, and “ethylene vinyl alcohol copolymer film layer deposited with aluminum”. This prevents the occurrence of “heat shrinkage wrinkles” and “sagging” due to the above, and thereby can eliminate the quality defect (15.5%) that occurs in Comparative Examples 1 and 2. As a result, Examples 1 and 2 are comparative examples. The yield was improved by 15.5% with respect to 1 and 2.

Further, the moisture permeability and oxygen gas permeability of the laminates of Examples 1 and 2 and Comparative Examples 1 and 2 were evaluated, and the results are shown in Tables 1 and 2. The moisture permeability test was measured in an environment of 40 ° C. and 90% RH, and the oxygen gas permeability was measured in an environment of 23 ° C. and 60% RH.
Moisture permeability:
Measured according to JIS Z 0208 [moisture permeability test (cup method)] Unit: g / m ² · day
Oxygen gas permeability:
Measured with MOCON OX-TRAN MODEL 2/21 Unit is ml / m ² · day · MPa

  As is clear from Tables 1 and 2, Example 1 has the same results in both moisture permeability and oxygen gas permeability as compared to Comparative Example 1, and Example 2 is more transparent than Comparative Example 2. The humidity was slightly superior, and the oxygen gas permeability was equivalent, and both showed favorable results as a laminate for a vacuum heat insulating material.

DESCRIPTION OF SYMBOLS 1 Laminated body for vacuum heat insulating materials 1 'Outer covering material 2 Vacuum heat insulating material 11 Base material layer 12 Water vapor gas barrier layer 13 Oxygen gas barrier layer 14 Thermal adhesive resin layer 20 Thermal insulation core material A Thermal bonding part

Claims (4)

In a laminated body for vacuum insulation used in a vacuum insulation material in which a heat insulation core material is enclosed with an outer envelope material made of a laminate and the inside enclosed with the outer envelope material is evacuated to be in a vacuum state. Layer, a water vapor gas barrier layer, an oxygen gas barrier layer, and a heat-adhesive resin layer in this order, and the oxygen gas barrier layer is a biaxially stretched three-layer coextruded film (nylon / ethylene) with aluminum deposition on one side A laminate for a vacuum heat insulating material, characterized in that it is made of a vinyl alcohol copolymer / nylon). The laminate for a vacuum heat insulating material according to claim 1, wherein the water vapor gas barrier layer is a biaxially stretched polyester film in which a vapor deposition layer of an inorganic substance or a metal oxide is formed. The laminate for a vacuum heat insulating material according to claim 2, wherein the vapor deposition layer of the water vapor gas barrier layer and the vapor deposition layer of the oxygen gas barrier layer are opposed to each other via an adhesive layer. The heat insulation core material is enclosed in the outer envelope material using the laminate for a vacuum heat insulating material according to any one of claims 1 to 3, and the outer envelope material is deaerated and sealed in a vacuum state. The vacuum heat insulating material characterized by being made.

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