JP2023015849A - Laminate for vacuum heat insulation material outer package - Google Patents

Abstract

To provide a carbon-neutral laminate for vacuum heat insulation material outer package that is superior in cold moldability and sticking resistance and also uses a biomass-derived raw material.SOLUTION: The present invention relates to a laminate for vacuum heat insulation material outer package that is a laminate which has at least a base material layer 1, an adhesion layer, a metal foil layer, and a sealant layer laminated in this order, wherein the base material layer 1 is a biaxially drawn polyamide film satisfying (a) to (c). Namely, (a) the film is 8 to 30 μm thick, and contains 1 to 30% of biomass-derived carbon for the whole carbon in the base material 1 when radioactive carbon (C14) is measured, and also has a sticking strength of 0.7 N/μm or larger measured in the JIS Z 1707 manner.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a laminated film suitable for use as an exterior material for vacuum insulation materials.

In recent years, the reduction of greenhouse gases has been promoted in order to prevent global warming, and there is a demand for energy saving in electrical products, vehicles, equipment, buildings, and the like. Above all, from the viewpoint of reducing power consumption, the use of vacuum insulation materials in electric appliances and the like is being promoted. For equipment that has a heat-generating part inside the main body, such as electrical appliances, or equipment that has a heat retention function that uses heat from the outside, it is possible to improve the insulation performance of the entire equipment by installing vacuum insulation materials. becomes. For this reason, efforts are being made to reduce the energy consumption of equipment such as electrical appliances by using vacuum insulation materials.

A vacuum heat insulating material is formed by enclosing a core material in an outer wrapping material, depressurizing the inside of the outer wrapping material to create a vacuum state, and sealing the ends of the outer wrapping material by heat welding. By creating a vacuum inside the heat insulating material, gas convection is cut off, so the vacuum heat insulating material can exhibit high heat insulating performance. Further, in order to maintain the heat insulation performance of the vacuum heat insulating material for a long period of time, it is necessary to keep the inside of the outer wrapping material in a high vacuum state for a long period of time. Therefore, the outer wrapping material is required to have various functions such as gas barrier properties for preventing permeation of gas from the outside, and thermal adhesion properties for covering and tightly sealing the core material. Therefore, the outer packaging material is constructed as a laminate having a plurality of films having these functional characteristics. A general form of the outer packaging material is one in which a heat-sealable layer, a gas barrier layer and a protective layer are laminated, and the respective layers are bonded together via an adhesive or the like.

As the base material layer of the exterior material for the vacuum heat insulating material as described above, for example, by using a stretched nylon film alone or a laminate of a nylon film and a polyester film, needle-shaped inorganic fibers such as glass wool are cut. A technique has been known in which even when fiber powder is filled, the occurrence of pinholes due to piercing of needle-shaped short fiber powder can be suppressed (see, for example, Patent Document 1). Those manufactured from raw materials have been used.

On the other hand, in recent years, the use of biomass instead of fossil fuel raw materials has attracted attention in the field of materials in order to build a recycling-oriented society. Biomass is an organic compound that is photosynthesised from carbon dioxide and water. By using it, it becomes carbon dioxide and water again. It is a raw material that can suppress the increase of carbon dioxide, which is a greenhouse gas. Biomass plastics using these biomass as raw materials have been rapidly put to practical use, and biaxially stretched polyamide films using biomass-derived raw materials have also been proposed (Patent Document 2).

JP 2006-77799 A International Publication No. 2020/170714

An object of the present invention is to suppress the occurrence of pinholes due to piercing of needle-like short fiber powder even when needle-like fiber powder obtained by cutting inorganic fibers such as glass wool is filled, and to suppress the occurrence of pinholes caused by needle-like short fiber powder. An object of the present invention is to provide a carbon-neutral vacuum heat insulating material exterior laminate using a raw material.

The present invention consists of the following configurations.
[1] A laminate in which at least a substrate layer 1, an adhesive layer, a metal foil layer and a sealant layer are laminated in this order, wherein the substrate layer 1 satisfies the following (a) to (c) biaxially stretched A vacuum insulation exterior laminate, which is a polyamide film.
(a) Thickness 8 to 30 μm
(b) The content of biomass-derived carbon measured by radioactive carbon (C14) is 1 to 30% relative to the total carbon in the base layer 1
(c) Puncture strength measured by JIS Z 1707 method is 0.7 N / μm or more [2] The base layer 1 is formed from a resin composition containing polyamide 6 and a polyamide whose raw material is at least partly derived from biomass The vacuum insulation exterior laminate according to [1], which is a biaxially stretched polyamide film consisting of a single layer of
[3] The base material layer 1 includes a layer (A layer) formed from a resin composition containing polyamide 6 and a polyamide at least part of which is derived from biomass, and polyamide 6, and at least one of the raw materials The vacuum insulation exterior laminate according to [1], which is a biaxially stretched polyamide film comprising at least two layers (layer B) formed from a resin composition that does not contain polyamide whose part is derived from biomass.
[4] [2] or [3], wherein the polyamide at least part of which is derived from biomass is at least one polyamide selected from the group consisting of polyamide 11, polyamide 410, polyamide 610 and polyamide 1010; Laminate for vacuum heat insulating material exterior according to the description.
[5] The vacuum insulation exterior laminate according to any one of [1] to [4], wherein the sealant layer is an unstretched polyolefin film.
[6] The stretched polyolefin film is a non-stretched polyolefin film containing 70 to 95% by mass of a polypropylene resin and 5 to 30% by mass of a linear low-density polyethylene resin whose raw material is at least partly derived from biomass. The vacuum insulation material exterior laminate according to [5].
[7] Any one of [1] to [6], wherein the content of biomass-derived carbon measured by radioactive carbon (C14) in the sealant layer is 3 to 30% of the total carbon in the sealant layer. Laminate for vacuum heat insulating material exterior according to the description.
[8] The vacuum heat insulation according to any one of [1] to [7], wherein a substrate layer 2 having a thickness of 10 to 30 μm is further laminated on the surface of the substrate layer 1 opposite to the metal foil layer. Laminate for material exterior.
[9] The vacuum heat insulating material exterior laminate according to [8], wherein the substrate layer 2 is a biaxially stretched polyester film.

According to the present invention, a biaxially stretched polyamide film obtained by blending a polyamide resin polymerized from a specific biomass-derived raw material with polyamide 6 is used as a base layer, and polyethylene using a biomass-derived raw material is blended with polypropylene. By laminating the sealant film, it is possible to obtain a vacuum heat insulating material exterior laminate that is excellent in puncture resistance and is carbon-neutral.

[Base material layer 1]
The substrate layer 1 of the present invention is a biaxially oriented polyamide film. The biaxially stretched polyamide film contains 70 to 99% by mass of polyamide 6 and 1 to 30% by mass of polyamide whose raw material is at least partly derived from biomass as the polyamide resin. By containing 70% by mass or more of polyamide 6, excellent mechanical strength such as impact strength and gas barrier properties against oxygen, which are inherent to a biaxially stretched polyamide film made of polyamide 6, can be obtained. In addition, by containing 1 to 30% by mass of polyamide, at least part of which is derived from biomass, not only is there little effect on changes in carbon dioxide on the ground, but also the puncture resistance is improved.

As one preferred embodiment, the substrate layer 1 is a biaxially stretched polyamide film consisting of a single layer formed from a resin composition containing polyamide 6 and a polyamide at least part of which is derived from biomass.

In another preferred embodiment, the base material layer 1 includes a layer (A layer) formed from a resin composition containing polyamide 6 and a polyamide at least part of which is derived from biomass, and polyamide 6, and the raw material It is a biaxially stretched polyamide film comprising at least two layers (layer B) formed from a resin composition that is at least partially derived from biomass and does not contain polyamide. Specific examples include a two-layer structure of A layer/B layer and a three-layer structure of B layer/A layer/B layer.

<Polyamide 6>
Polyamide 6 used in the present invention is usually produced by ring-opening polymerization of ε-caprolactam. Polyamide 6 obtained by ring-opening polymerization is usually melt-extruded by an extruder after removing the lactam monomer with hot water and then drying.

The relative viscosity of polyamide 6 is preferably 1.8-4.5, more preferably 2.6-3.2. If the relative viscosity is less than 1.8, the impact strength of the film will be insufficient. If it is more than 4.5, the load on the extruder is increased, making it difficult to obtain an unstretched film before stretching.

As polyamide 6, in addition to those polymerized from commonly used fossil fuel-derived monomers, polyamide 6 chemically recycled from waste polyamide 6 products such as waste plastic products, waste tire rubber, fibers, and fishing nets can also be used. As a method of obtaining chemically recycled polyamide 6 from waste polyamide 6 products, for example, after collecting used polyamide products, depolymerization is performed to obtain ε-caprolactam, which is purified and then polyamide 6 is obtained. A method of polymerization can be used.

In addition, polyamide 6 obtained by mechanically recycling waste material from the production process of the polyamide film can be used together. Mechanically recycled polyamide 6 is, for example, a non-standard film that cannot be shipped when manufacturing a biaxially stretched polyamide film, and waste materials generated as cut ends (edge trim) are collected and melted extrusion or compression molding. It is a raw material pelletized by

<Polyamide at least part of which is derived from biomass>
Examples of the polyamide at least partly derived from biomass used in the present invention include polyamide 11, polyamide 410, polyamide 610, and polyamide 1010.

Polyamide 11 is a polyamide resin having a structure in which monomers having 11 carbon atoms are bonded via amide bonds. Polyamide 11 is usually obtained using aminoundecanoic acid or undecanelactam as a monomer. In particular, aminoundecanoic acid is desirable from the viewpoint of carbon neutrality because it is a monomer obtained from castor oil.

Polyamide 410 is a polyamide resin having a structure in which a monomer having 4 carbon atoms and a diamine having 10 carbon atoms are copolymerized. Polyamide 410 typically utilizes sebacic acid and tetramethylene diamine. Sebacic acid is preferably made from castor oil, which is a vegetable oil, from an environmental point of view. Sebacic acid used here is preferably obtained from castor oil from the viewpoint of environmental protection (especially from the viewpoint of carbon neutrality).

Polyamide 610 is a polyamide resin having a structure in which a diamine having 6 carbon atoms and a dicarboxylic acid having 10 carbon atoms are polymerized. Hexamethylenediamine and sebacic acid are commonly used. Of these, sebacic acid is a monomer obtained from castor oil, and is desirable from the viewpoint of carbon neutrality.

Polyamide 1010 is a polyamide resin having a structure in which a diamine having 10 carbon atoms and a dicarboxylic acid having 10 carbon atoms are polymerized. Polyamide 1010 typically utilizes 1,10-decanediamine (decamethylenediamine) and sebacic acid. Decamethylenediamine and sebacic acid are monomers obtained from castor oil, and thus are desirable from the carbon neutral point of view.

The lower limit of the content of the polyamide, at least part of which is derived from biomass, in the substrate layer of the present invention is not particularly limited, but is preferably 1% by mass, more preferably 3% by mass or more. The upper limit of the content is 30% by mass, more preferably 20% by mass. If the content of the polyamide, at least part of which is derived from biomass, exceeds 30% by mass, the melted film may become unstable during casting, making it difficult to obtain a homogeneous non-stretched film.

<Secondary materials, additives>
Various additives such as other thermoplastic resins, lubricants, heat stabilizers, antioxidants, antistatic agents, antifogging agents, ultraviolet absorbers, dyes, and pigments are added to the biaxially stretched polyamide film of the base layer. It can be contained as needed.

<Other thermoplastic resins>
The biaxially stretched polyamide film of the base layer may contain a thermoplastic resin in addition to the polyamide 6 and the polyamide resin at least part of which is derived from biomass, as long as the object of the present invention is not impaired. . Examples thereof include polyamide resins such as polyamide 12 resin, polyamide 66 resin, polyamide 6/12 copolymer resin, polyamide 6/66 copolymer resin, and polyamide MXD6 resin. Thermoplastic resins other than polyamides, for example, polyester polymers such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate, and polyolefin polymers such as polyethylene and polypropylene, may be added as necessary. good. It is preferable that the raw materials of these thermoplastic resins are biomass-derived, since they do not affect the increase or decrease of carbon dioxide on the ground, thereby reducing the environmental load.

<Lubricant>
The biaxially stretched polyamide film of the substrate layer may contain fine particles as a lubricant in order to improve slipperiness and facilitate handling. As the fine particles, inorganic fine particles such as silica, kaolin, and zeolite, and polymer-based organic fine particles such as acryl-based and polystyrene-based organic fine particles can be appropriately selected and used. From the viewpoint of transparency and slipperiness, it is preferable to use fine silica particles. The fine particles preferably have an average particle size of 0.5 to 5.0 μm, more preferably 1.0 to 3.0 μm. If the average particle size is less than 0.5 μm, a large amount of addition is required to obtain good slipperiness. On the other hand, when it exceeds 5.0 μm, the surface roughness of the film tends to be too large and the appearance tends to be poor.

When the silica fine particles are used, the pore volume of silica is preferably 0.5 to 2.0 ml/g, more preferably 0.8 to 1.6 ml/g. When the pore volume is less than 0.5 ml/g, voids are likely to occur and the transparency of the film deteriorates. Tend.

The biaxially stretched polyamide film of the substrate layer may contain a fatty acid amide and/or a fatty acid bisamide for the purpose of improving slipperiness. Fatty acid amides and/or fatty acid bisamides include erucic acid amide, stearic acid amide, ethylene bis stearic acid amide, ethylene bis behenic acid amide, ethylene bis oleic acid amide and the like. The content of fatty acid amide and/or fatty acid bisamide is preferably 0.01 to 0.40% by mass, more preferably 0.05 to 0.30% by mass. If the content of the fatty acid amide and/or the fatty acid bisamide is less than the above range, the lubricity tends to deteriorate. On the other hand, when the above range is exceeded, the wettability tends to deteriorate.

When the substrate layer 1 is composed of at least two layers, A layer and B layer, it is preferable that only the B layer contains the fine particles, the fatty acid amide and/or the fatty acid bisamide. When the amount of these added to the A layer is reduced, the effect of obtaining a film with excellent transparency and slipperiness can be expected.

<Antioxidant>
The biaxially stretched polyamide film of the substrate layer can contain an antioxidant. Phenolic antioxidants are preferred as antioxidants. The phenolic antioxidant is preferably a fully hindered phenolic compound or a partially hindered phenolic compound. For example, tetrakis-[methylene-3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate]methane, stearyl-β-(3,5-di-t-butyl-4-hydroxy phenyl)propionate, 3,9-bis[1,1-dimethyl-2-[β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]2,4,8,10- tetraoxaspiro[5,5]undecane and the like. By containing a phenolic antioxidant, the film-forming operability of the biaxially stretched polyamide film is improved. In particular, when a recycled film is used as a raw material, thermal deterioration of the resin tends to occur, resulting in poor film-forming operation, which tends to lead to an increase in production cost. On the other hand, by containing an antioxidant, the heat deterioration of the resin is suppressed and the workability is improved.

The base material layer 1 preferably does not contain a polyamide-based elastomer or a polyolefin-based elastomer. By not containing a soft resin such as a polyamide-based elastomer or a polyolefin-based elastomer or a substance that generates a large amount of voids, the friction pinhole resistance is improved.

[Biaxially stretched polyamide film]
The thickness of the base material layer is not particularly limited, but when it is used as a vacuum insulation exterior laminate, it is usually 100 μm or less, and generally has a thickness of 5 to 50 μm, particularly 8 to 8 μm. 30 μm is used.

The biaxially stretched polyamide film of the substrate layer preferably has a heat shrinkage rate of 0.6 to 3.0% in both the MD and TD directions at 160° C. for 10 minutes, more preferably 0.5%. 6 to 2.5%. If the heat shrinkage rate exceeds 3.0%, curling or shrinkage may occur when heat is applied in the next step such as lamination or printing. Moreover, the lamination strength with the sealant film may be weakened. Although it is possible to set the heat shrinkage to less than 0.6%, it may become mechanically brittle. Moreover, it is not preferable because productivity deteriorates.

The impact strength of the biaxially stretched polyamide film is preferably 0.7 J/15 μm or more. A more preferable impact strength is 0.9 J/15 μm or more.

The puncture strength of the biaxially stretched polyamide film is preferably 0.7 N/μm or more. A more preferable puncture strength is 0.9 N/μm or more.

The haze value of the biaxially stretched polyamide film is preferably 10% or less. More preferably 7% or less, still more preferably 5% or less. If the haze value is small, the transparency and gloss are good, so when a printed layer is provided on the vacuum insulation exterior laminate, clear printing can be performed and the commercial value is increased. Addition of fine particles to improve the slipperiness of the film increases the haze value. Therefore, when the film has two or more layers, the haze value can be reduced by adding fine particles only to the surface layer.

The dynamic friction coefficient of the biaxially stretched polyamide film is preferably 1.0 or less. It is more preferably 0.7 or less, still more preferably 0.5 or less. If the coefficient of dynamic friction of the film is small, the slipperiness is improved and the handling of the film is facilitated. If the coefficient of dynamic friction of the film is too small, the film will be too slippery and difficult to handle.

The biaxially stretched polyamide film has a biomass-derived carbon content (also referred to as biomass degree) measured by radioactive carbon (C14) of ASTM D6866-16 Method B of 1 to 30 mol% relative to the total carbon in the polyamide film. preferably included. Since carbon dioxide in the atmosphere contains a certain proportion of C14 (105.5 pMC), the C14 content in plants that grow by taking in carbon dioxide in the atmosphere, such as corn, is also about 105.5 pMC. It is known. It is also known that fossil fuels contain almost no C14. Therefore, by measuring the ratio of C14 contained in the total carbon atoms in the film, the ratio of biomass-derived carbon can be calculated.

[Method for producing biaxially stretched polyamide film]
The biaxially stretched polyamide film of the substrate layer can be produced by a known production method. A typical production example is described below.

First, a raw material resin is melt extruded using an extruder, extruded in the form of a film through a T-die, cast on a cooling roll and cooled to obtain a non-stretched film. The melting temperature of the resin is preferably 220-350°C. If it is less than the above range, unmelted materials may occur, resulting in appearance defects such as defects. The die temperature is preferably 250-350°C.

When producing a biaxially stretched polyamide film in which at least two layers of the A layer and the B layer are laminated, a coextrusion method using a feed block or a multi-manifold is used to laminate the A layer and the B layer without stretching. you can get the film. When laminating by coextrusion, it is desirable that the polyamide resin composition used for the A layer and the B layer has a small difference in melt viscosity between the A layer and the B layer.

The cooling roll temperature is preferably -30 to 80°C, more preferably 0 to 50°C. In order to obtain a non-stretched film by casting the film-shaped melt extruded from the T-die onto a rotating cooling drum and cooling it, for example, a method using an air knife or an electrostatic adhesion method in which static charge is applied is preferably applied. can. Especially the latter is preferably used.

In addition, it is preferable to cool the opposite side of the cast unstretched film to the cooling roll. For example, it is preferable to use a method of contacting the opposite side of the unstretched film with a cooling liquid in a tank, a method of applying a liquid that transpires with a spray nozzle, a method of cooling by spraying a high-speed fluid, and the like. . The unstretched film thus obtained is biaxially stretched to obtain the biaxially stretched polyamide film of the present invention.

The stretching method may be a simultaneous biaxial stretching method or a sequential biaxial stretching method. In any case, as the stretching method in the MD direction, single-stage stretching or multi-stage stretching such as two-stage stretching can be used. As will be described later, multi-stage stretching in the MD direction such as two-stage stretching is preferable in terms of physical properties and uniformity (isotropy) of physical properties in the MD and TD directions, rather than single-stage stretching. Stretching in the MD direction in the sequential biaxial stretching method is preferably roll stretching.

The lower limit of the stretching temperature in the MD direction is preferably 50°C, more preferably 55°C, still more preferably 60°C. If the temperature is less than 50°C, the resin may not be softened, making stretching difficult. The upper limit of the stretching temperature in the MD direction is preferably 120°C, more preferably 115°C, still more preferably 110°C. If the temperature exceeds 120°C, the resin may become too soft to allow stable stretching.

The lower limit of the draw ratio in the MD direction (in the case of multistage drawing, the total draw ratio obtained by multiplying each draw ratio) is preferably 2.2 times, more preferably 2.5 times, and still more preferably 2.5 times. 8 times. If it is less than 2.2 times, the thickness accuracy in the MD direction may be lowered, and the crystallinity may be too low to lower the impact strength. The upper limit of the draw ratio in the MD direction is preferably 5.0 times, more preferably 4.5 times, and most preferably 4.0 times. If it exceeds 5.0 times, subsequent stretching may become difficult.

Further, when the stretching in the MD direction is performed in multiple stages, the stretching as described above is possible in each stretching. It is necessary to adjust the draw ratio. For example, in the case of two-stage stretching, the first stage stretching is preferably 1.5 to 2.1 times, and the second stage stretching is preferably 1.5 to 1.8 times.

A film stretched in the MD direction is stretched in the TD direction by a tenter, heat-set, and subjected to relaxation treatment (also referred to as relaxation treatment). The lower limit of the stretching temperature in the TD direction is preferably 50°C, more preferably 55°C, still more preferably 60°C. If the temperature is less than 50°C, the resin may not be softened, making stretching difficult. The upper limit of the stretching temperature in the TD direction is preferably 190°C, more preferably 185°C, still more preferably 180°C. If the temperature exceeds 190°C, crystallization may occur, making stretching difficult.

The lower limit of the draw ratio in the TD direction (in the case of multistage drawing, the total draw ratio obtained by multiplying each draw ratio) is preferably 2.8, more preferably 3.2, and still more preferably 3.5. times, particularly preferably 3.8 times. If it is less than 2.8, the thickness accuracy in the TD direction may be lowered, and the crystallinity may be too low to lower the impact strength. The upper limit of the draw ratio in the TD direction is preferably 5.5 times, more preferably 5.0 times, still more preferably 4.7 times, particularly preferably 4.5 times, and most preferably 4.5 times. Three times. If it exceeds 5.5 times, the productivity may be remarkably lowered.

The lower limit of the heat setting temperature is preferably 210°C, more preferably 212°C. When the heat setting temperature is low, the heat shrinkage rate becomes too large, and the appearance after lamination tends to deteriorate, and the lamination strength tends to decrease. The upper limit of the heat setting temperature is preferably 220°C, more preferably 218°C. If the heat setting temperature is too high, the impact strength tends to decrease.

The heat setting time is preferably 0.5 to 20 seconds. Furthermore, it is 1 to 15 seconds. The heat setting time can be set to an appropriate time in consideration of the heat setting temperature and the wind speed in the heat setting zone. If the heat setting conditions are too weak, crystallization and orientation relaxation become insufficient, causing the above problems. If the heat setting conditions are too strong, the toughness of the film will decrease.

Relaxation treatment after heat setting treatment is effective in controlling the thermal shrinkage rate. The temperature for the relaxation treatment can be selected in the range from the heat setting temperature to the glass transition temperature (Tg) of the resin, but the heat setting temperature -10°C to Tg + 10°C is preferable. If the relaxation temperature is too high, the shrinkage speed will be too fast, causing distortion and the like, which is not preferable. Conversely, if the relaxation temperature is too low, the relaxation treatment will not be performed, and the film will simply loosen, the heat shrinkage rate will not decrease, and the dimensional stability will deteriorate.

The lower limit of the relaxation rate of the relaxation process is preferably 0.5%, more preferably 1%. If it is less than 0.5%, the heat shrinkage rate may not sufficiently decrease. The upper limit of the relaxation rate is preferably 20%, more preferably 15%, still more preferably 10%. If it exceeds 20%, sagging may occur in the tenter, making production difficult.

Furthermore, the biaxially stretched polyamide film of the substrate layer can be subjected to heat treatment or humidity control treatment in order to improve the dimensional stability depending on the application. In addition, in order to improve the adhesiveness of the film surface, it is possible to perform corona treatment, coating treatment, flame treatment, etc., printing, vapor deposition of metals and inorganic oxides, etc. It is also possible. As the vapor deposition film formed by the vapor deposition process, a vapor deposition film of aluminum, a vapor deposition film of a single substance or a mixture of silicon oxide or aluminum oxide is preferably used. Furthermore, by coating a protective layer or the like on these vapor-deposited films, the oxygen barrier properties and the like can be improved.

[Sealant layer]
Preferably, the sealant layer is an unstretched polyolefin film. As the unstretched polyolefin film, a film containing a polyethylene-based resin composition and/or a polypropylene-based resin composition is preferable.

When the sealant layer is mainly formed from a polyethylene-based resin composition, examples of the polyethylene-based resin composition include linear low-density polyethylene (LLDPE) and low-density polyethylene (LDPE). The sealant layer may have a single layer structure or a multilayer structure of two or more layers, and includes at least one layer formed from a polyethylene resin composition, and a layer made of any other resin. Although it may contain, the total of the layers formed from the polyethylene resin composition of the present invention in the entire sealant film is preferably 40% by mass or more and 100% by mass or less.

Linear low-density polyethylene can be produced by a production method such as a high-pressure method, a solution method, or a gas phase method. Examples of linear low-density polyethylene include copolymers of ethylene and at least one α-olefin having 3 or more carbon atoms. As the α-olefin, what is generally called α-olefin may be used, and α- Olefins are preferred. Examples of copolymers of ethylene and α-olefin include ethylene/hexene-1 copolymer, ethylene/butene-1 copolymer, ethylene/octene-1 copolymer, etc. Ethylene-hexene copolymers are preferred from the viewpoint.

Linear low-density polyethylene is a biomass-derived linear low-density polyethylene polymerized using ethylene derived from plants such as sugar cane and ethylene derived from fossil fuels such as petroleum or plants as part of the raw material. can contain. From the viewpoint of carbon neutrality, biomass-derived linear low-density polyethylene is said to be effective in reducing the amount of carbon dioxide generated, and to be able to suppress global warming. When the biomass-derived ethylene of the biomass-derived linear low-density polyethylene is included, the content is preferably 50% by mass or more, more preferably 80% by mass or more. When it is 50% or more, the carbon dioxide reduction effect is good. The upper limit is preferably 98%, more preferably 96%. Since it is preferable to copolymerize an α-olefin other than ethylene from the viewpoint of cold formability, it is preferably 98% by mass or less.

When the sealant layer is mainly formed from a polypropylene resin composition, 70 to 95% by mass of polypropylene resin and 5 to 30% by mass of linear low-density polyethylene resin in which at least part of the raw material is derived from biomass. % is preferred. The sealant layer may have a single-layer structure or a multi-layer structure of two or more layers, but one embodiment includes a structure having a seal layer, a core layer, and a laminate layer in this order. The seal layer and laminate layer are layers positioned on the surface side of the unstretched polyolefin film, and the core layer is positioned between them. When the non-stretched polyolefin film is used as a vacuum insulation exterior laminate, the laminate layer is a layer suitable for bonding metal foils together, and in practice it is preferable to laminate via an adhesive resin. The sealing layer is a layer suitable for heat-sealing to produce vacuum insulation. By adopting the above layer structure, it is possible to contain more biomass-derived linear low-density polyethylene resin while maintaining the properties of the unstretched polypropylene film, which is a sealant layer with excellent heat resistance.

In this case, the difference in content of the linear low-density polyethylene in the polypropylene-based resin composition constituting the seal layer and the core layer is preferably 1 to 28% by mass. More preferably 1 to 23% by mass, still more preferably 1 to 18% by mass, particularly preferably 1 to 15% by mass. By setting the difference in content to 28% by mass or less, the interlaminar strength at the interface between the seal layer and the core layer can be kept high. The difference in content of the linear low-density polyethylene in the polypropylene-based resin composition constituting the core layer and the laminate layer is preferably 1 to 28% by mass. It is more preferably 1 to 23% by weight, still more preferably 1 to 18% by weight, and particularly preferably 1 to 15% by weight. By setting the difference in content to 28% by mass or less, the interlaminar strength at the interface between the core layer and the laminate layer can be kept high.

The polypropylene-based resin composition preferably contains a propylene-α-olefin random copolymer. A copolymer of propylene and at least one α-olefin having 2 or 4 to 20 carbon atoms other than propylene can be mentioned. Examples of α-olefin monomers having 2 or 4 to 20 carbon atoms include ethylene, butene-1, pentene-1, 4-methylpentene-1, hexene-1 and octene-1.

Ethylene is preferably used for the propylene-α-olefin random copolymer from the viewpoint of heat sealability. At least one type or more may be used, and two or more types may be mixed and used as needed. Particularly suitable is a propylene-ethylene-butene random copolymer in which the main monomer is propylene and certain amounts of ethylene and butene are copolymerized.

<Additive>
In the non-stretched polyolefin film, suitable amounts of antiblocking agent, antioxidant, antistatic agent, antifogging agent, neutralizer, nucleating agent, Colorants, other additives, inorganic fillers, and the like may be included.

The unstretched polyolefin film may contain an antiblocking agent. One type of anti-blocking agent may be used, but it is better to blend two or more types of inorganic particles with different particle sizes and shapes. be able to. The anti-blocking agent to be added is not particularly limited, but inorganic particles such as spherical silica, amorphous silica, zeolite, talc, mica, alumina, hydrotalcite, aluminum borate, polymethyl methacrylate, ultra high molecular weight Organic particles such as polyethylene can be added.

The unstretched polyolefin film can contain an organic lubricant. By containing an organic lubricant, the lubricity and anti-blocking effect of the film are improved, and the handleability of the film is improved. It is believed that the reason for this is that the organic lubricant bleeds out and is present on the film surface, thereby exhibiting the lubricant effect and the release effect. The organic lubricant preferably has a melting point above room temperature. Examples of organic lubricants include fatty acid amides and fatty acid esters. Specific examples include oleic acid amide, erucic acid amide, behenic acid amide, ethylenebisoleic acid amide, hexamethylenebisoleic acid amide, and ethylenebisoleic acid amide. These may be used alone, but it is preferable to use two or more of them in combination because the lubricity and anti-blocking effect can be maintained even in a harsh environment.

The unstretched polyolefin film can contain an antioxidant. Examples of antioxidants include phenolic antioxidants, phosphite antioxidants, combinations thereof, and those having phenolic and phosphite skeletons in one molecule. Calcium stearate etc. are mentioned as a neutralizing agent.

[Unstretched polyolefin film]
The lower limit of the thickness of the non-stretched polyolefin film of the sealant layer is preferably 15 μm, more preferably 20 μm, still more preferably 25 μm. When the thickness is 15 μm or more, it is easy to obtain heat seal strength and bag breakage resistance. The upper limit of the film thickness is preferably 80 µm, more preferably 70 µm, still more preferably 60 µm, and particularly preferably 50 µm. When the thickness is 80 μm or less, the film does not have too strong a feeling of stiffness and is easy to process, and it is easy to produce a suitable laminate for vacuum insulation material exterior.

The impact strength of the non-stretched polyolefin film is preferably 0.20J/15 μm or more, more preferably 0.25J, still more preferably 0.30J. By setting it to 0.20 J or more, it is possible to improve the drop bag breakage resistance of the vacuum insulation material exterior. An impact strength of 1.0 J is sufficient. Impact strength is highly dependent on the thickness and molecular orientation of the film.

The unstretched polyolefin film preferably has a puncture strength of 1.0 N or more, more preferably 1.5 N or more, and still more preferably 1.7 N or more. When the thickness is 1.0 μm or more, the laminate has good pierce pinhole resistance.

The plane orientation coefficient of the unstretched polyolefin film is preferably 0.000 or more, more preferably 0.001 or more. The upper limit of the plane orientation of the film is preferably 0.010 or less, more preferably 0.008 or less, and still more preferably 0.006 or less. If it is more than the above, the film may be stretched unevenly and the thickness uniformity may be deteriorated.

The non-stretched polyolefin film has a biomass-derived carbon content (also referred to as biomass degree) measured by radioactive carbon (C14) of ASTM D6866-16 of 3 to 30 mol% based on the total carbon in the unstretched polyolefin film. preferably

[Method for producing unstretched polyolefin film]
As the method for producing the unstretched polyolefin film in the present invention, for example, an inflation method or a T-die method can be used, but the T-die method is preferable in order to improve transparency. The inflation method uses air as a cooling medium, whereas the T-die method uses cooling rolls, and is therefore an advantageous manufacturing method for increasing the cooling rate. By increasing the cooling rate, crystallization of the non-stretched sheet can be suppressed, and transparency is advantageous.

[Metal foil layer]
Various metal foils such as aluminum foil and stainless steel foil can be used as the metal foil layer, and aluminum foil is preferable from the viewpoint of workability such as moisture resistance and extensibility, and cost. A general soft aluminum foil can be used as the aluminum foil. Among them, aluminum foil containing iron is preferable from the viewpoint of excellent pinhole resistance and extensibility during molding. The iron content in the iron-containing aluminum foil (100% by mass) is preferably 0.1 to 9.0% by mass, more preferably 0.5 to 2.0% by mass. If the iron content is equal to or higher than the lower limit, the exterior material 1 is excellent in pinhole resistance and extensibility. If the iron content is 9.0% by mass or less, the exterior material 1 is excellent in flexibility. The thickness of the metal foil layer is preferably 9 to 200 μm, more preferably 15 to 100 μm, from the viewpoints of barrier properties, pinhole resistance and workability.

[Adhesion layer]
The adhesive layer is a layer provided to firmly bond the base material layer 1 and the metal layer. The adhesive used for the adhesive layer may be a two-component curing adhesive or a one-component curing adhesive. Furthermore, the adhesion mechanism of the adhesive used to form the adhesive layer 5 is not particularly limited, and may be any of chemical reaction type, solvent volatilization type, heat melting type, heat pressure type, and the like.

Specific adhesive components that can be used to form the adhesive layer include polyester resins, polyurethane adhesives; epoxy resins, phenol resins, polyamide resins, polyolefin resins, polyvinyl acetate resins, and cellulose resins. Examples thereof include adhesives, (meth)acrylic resins, polyimide resins, urea resins, amino resins such as melamine resins, rubbers, and silicone resins. These adhesive components may be used singly or in combination of two or more.

[Base material layer 2]
The laminate for exterior vacuum insulation according to the present invention may further include a substrate layer 2 on the opposite side of the substrate layer 1 to the metal layer for the purpose of imparting electrolyte resistance, heat resistance, and the like. As a layer used for the substrate layer 2, a biaxially stretched polyester film such as a biaxially stretched polyethylene terephthalate film and a biaxially stretched polybutylene terephthalate film can be suitably used. Among them, a biaxially stretched polyethylene terephthalate film is preferable from the viewpoint of heat resistance and chemical resistance.

As the polyethylene terephthalate film used as the base material layer 2 of the vacuum insulation material exterior laminate of the present invention, in addition to the conventionally used polyethylene terephthalate film composed of petroleum-derived raw materials, biomass-derived ethylene glycol and fossil fuel-derived A biaxially oriented polyethylene terephthalate film can be used which is characterized by being composed of dicarboxylic acid units of
Among them, by using a biaxially stretched polyethylene terephthalate film characterized by being composed of biomass-derived ethylene glycol and fossil fuel-derived dicarboxylic acid units, the degree of biomass as a laminate is improved, and the carbon dioxide above the ground is improved. Since it does not affect the increase or decrease of carbon, it is preferable because it can reduce the environmental load.

[Vacuum insulation material laminate]
The vacuum insulation material exterior laminate of the present invention has at least a substrate layer 1, an adhesive layer, a metal layer, and a sealant layer. A laminated film can also be constructed with an adhesive layer, a printed layer, or the like interposed therebetween. As a lamination method, known methods such as dry lamination and extrusion lamination can be used, but any lamination method may be used.

The vacuum insulation exterior laminate has a biomass-derived carbon content (also referred to as biomass degree) measured by ASTM D6866-16 radioactive carbon (C14) relative to the total carbon in the vacuum insulation exterior laminate. It is preferably contained in an amount of 2 to 30 mol %.

The puncture strength of the vacuum insulation exterior laminate is preferably 18 N or more, more preferably 20 N or more, from the viewpoint of suppressing the generation of pinholes due to the puncture of needle-like short fiber powder, which is the content of the vacuum insulation material.

Film evaluation was performed by the following measurement methods. Unless otherwise specified, measurements were carried out in a measurement room at 23° C. and a relative humidity of 65%.

(1) Thickness of Film The film thus obtained is cut into a length of 100 mm in a stack of 10 sheets, and is conditioned at a temperature of 23° C. and a relative humidity of 65% for 2 hours or more. After that, the width direction of the film is divided into 10 equal parts (for narrow films, the width is divided so that the width that can measure the thickness can be secured), and the thickness is measured using a thickness measuring instrument manufactured by Tester Sangyo. The thickness of the film was obtained by dividing the average value by the number of films stacked.
The thickness of the A layer was calculated based on the ratio of the resin discharge amounts of the A layer, the B layer, and the C layer.

(2) Haze value The haze value of the film was measured according to JIS K7105 using a direct-reading haze meter manufactured by Toyo Seiki Seisakusho.

(3) Degree of biomass The degree of biomass of the film was determined by measuring radiocarbon (C14) according to ASTM D6866-16 Method B (AMS).

(4) Thermal shrinkage rate The thermal shrinkage rate of the film is determined by the following formula according to the dimensional change test method described in JIS C2318, except that the test temperature is 160 ° C and the heating time is 10 minutes in each of the MD and TD directions. It was measured.
Thermal shrinkage = [(length before treatment - length after treatment) / length before treatment] x 100 (%)

(5) Impact strength The impact strength of the film was measured using a film impact tester manufactured by Toyo Seiki Seisakusho. The measured value was expressed as J (joule)/15 μm in terms of a thickness of 15 μm.

(6) Degree of Plane Orientation A sample was obtained from the central position in the width direction of the film. According to JIS K 7142-1996 A method for the sample, the refractive index (nx) in the film longitudinal direction and the refractive index (ny) in the width direction are measured with an Abbe refractometer using sodium D line as a light source, and the calculation formula of formula (1) The degree of plane orientation was calculated by
Planar orientation (ΔP) = (nx + ny) / 2-nz (1)

(7) Puncture strength The pierce strength of the film is determined according to "2. Test methods for strength, etc." ” was measured in accordance with A needle with a tip diameter of 0.7 mm was pierced into the film at a piercing speed of 50 mm/min, and the strength (N) when the needle penetrated the film was measured. The measurement was performed at room temperature (23°C). The puncture strength (unit: N/μm) of the films of the substrate layer and the sealant layer was obtained by dividing the puncture strength (unit: N) of the obtained film by the actual thickness of the film. The puncture strength of the laminate was defined as the strength obtained by the above measurement as the puncture strength (N).

(8) Wetting Tension The wetting tension of the laminate layer surface was measured according to JIS-K6768 Plastics-Film and Sheet-Wet Tension Test Method.

[Production Example 1]
<Preparation of biaxially stretched polyamide film (ONY)>
(ONY1)
Using an apparatus consisting of two extruders and a co-extrusion T die with a width of 380 mm, a layer B/layer/B layer is laminated by the feed block method, and the molten resin is extruded into a film form from the T die and heated to 20°C. The film was cast on a cooling roll whose temperature was adjusted to 200 μm and electrostatically adhered to obtain a non-stretched film having a thickness of 200 μm.

A layer using the following resin composition for A layer and B layer:
Polyamide 6 (Toyobo Co., Ltd., relative viscosity 2.8, melting point 220 ° C.) 97 parts by mass; and polyamide 11 (Arkema Co., Ltd., relative viscosity 2.5, melting point 186 ° C.) 3.0 parts by mass
B layer:
Polyamide 6 (manufactured by Toyobo Co., Ltd., relative viscosity 2.8, melting point 220 ° C.) 95 parts by mass;
Polyamide MXD6 (manufactured by Mitsubishi Gas Chemical Co., Ltd., relative viscosity 2.1, melting point 237° C.) 5.0 parts by mass; 6 ml/g) 0.54 parts by mass; and 0.15 parts by mass of fatty acid bisamide (Ethiene bisstearic acid amide manufactured by Kyoeisha Chemical Co., Ltd.)

The total thickness of the biaxially stretched polyamide film was 15 μm, the thickness of the base layer (A layer) was 12 μm, and the thickness of each of the front and back surface layers (B layer) was 1.5 μm. The composition of the extruder and the discharge rate of the extruder were adjusted.

The obtained non-stretched film was guided to a roll type stretching machine, and after being stretched 1.73 times in the MD direction at 80°C by utilizing the peripheral speed difference of the rolls, it was further stretched 1.85 times at 70°C. Subsequently, this uniaxially stretched film was continuously guided to a tenter type stretching machine, preheated at 110°C, and stretched in the TD direction at 120°C for 1.2 times, 130°C for 1.7 times, and 160°C for 2.0 times. After stretching and heat setting treatment at 218° C., it was subjected to 7% relaxation treatment at 218° C., and then the surface of the side to be dry-laminated with the linear low density polyethylene film was subjected to corona discharge treatment to obtain a biaxially oriented polyamide film. rice field. Table 1 shows the evaluation results of the obtained biaxially stretched polyamide film.

(ONY2 to ONY15)
A biaxially stretched film was obtained in the same manner as ONY1 except that the film-forming conditions such as the raw material resin composition and the heat setting temperature were changed as shown in Table 1. Table 1 shows the evaluation results of the obtained biaxially stretched film. However, in ONY13, the molten resin could not be stably extruded in the form of a film from the T-die, and a homogeneous unstretched film could not be obtained, so biaxial stretching could not be performed.

Polyamide 410, polyamide 610, and polyamide 1010, which are polyamide resins at least partially containing raw materials derived from biomass, used the following.
Polyamide 410: (manufactured by DSM, ECOPaXX Q150-E, melting point 250°C)
Polyamide 610: (manufactured by Arkema, Rilsan S SMNO, melting point 222°C)
Polyamide 1010: (manufactured by Arkema, RilsanT TMNO, melting point 202°C)

[Production Example 2]
<Preparation of unstretched polyolefin film (CPP)>
(CPP1)
Based on the resin composition of each layer and its ratio shown in Table 2, raw materials were adjusted. With the content of each layer shown in Table 2 set to 100 parts by weight, 360 ppm of behenic acid amide as an organic lubricant and 2000 ppm of silica having an average particle size of 4 μm as an inorganic anti-blocking agent were added in a masterbatch to the sealing layer. bottom. A 2700 ppm masterbatch of behenic acid amide was added to the core layer as an organic lubricant.

(Raw material used in seal layer)
PP-1: Sumitomo Chemical propylene-ethylene-butene random copolymer FL6745A (MFR 6.0 g/10 min, melting point 130 ° C.)
Silica particles: Shin-Etsu Chemical Co., Ltd. amorphous silica KMP130-4 (average particle size 4 μm)
Organic lubricant: Behenic acid amide BNT-22H manufactured by Nippon Fine Chemical Co., Ltd.

(Raw materials used in the core layer)
PP-2: Sumitomo Chemical propylene-ethylene-butene random copolymer FL8115A (MFR 7.0 g/10 min, melting point 148 ° C.)
LL-1: Braskem ethylene-hexene copolymer (plant-derived linear low-density polyethylene) SLH218 (MFR 2.3 g/min, density 916 kg/m3, melting point 126° C.)
Organic lubricant: Behenic acid amide BNT-22H manufactured by Nippon Fine Chemical Co., Ltd.

(Raw materials used in laminate layer)
PP-2: Sumitomo Chemical propylene-ethylene-butene random copolymer FL8115A (MFR 7.0 g/10 min, melting point 148 ° C.)
LL-1: Braskem ethylene-hexene copolymer (plant-derived linear low-density polyethylene) SLH218 (MFR 2.3 g/min, density 916 kg/m3, melting point 126° C.)

A three-stage single screw extruder with a screw diameter of 90 mm is used for the mixed raw material used for the core layer, and a three-stage single screw extruder with a diameter of 65 mm and a diameter of 45 mm is used for the mixed raw material for the seal layer and the laminate layer, respectively. The resin is introduced in the order of layer/core layer/laminate layer, and the width of the resin is 800 mm, and the pre-land is divided into two stages. It was introduced into a T-slot type die designed as follows and extruded at a die outlet temperature of 230°C. The thickness ratios of the laminate layer/intermediate layer/heat seal layer were 25%/50%/25%, respectively.

The molten resin sheet coming out of the die was cooled with a cooling roll at 35° C. to obtain an unstretched polyolefin film having a thickness of 30 μm. When cooling on the cooling roll, both ends of the film on the cooling roll are fixed with air nozzles, the entire width of the molten resin sheet is pressed against the cooling roll with an air knife, and at the same time a vacuum chamber is applied between the molten resin sheet and the cooling roll. Prevents entrainment of air into Both ends of the air nozzle were installed in series in the film advancing direction. The die was surrounded by a sheet to prevent wind from hitting the molten resin sheet. Also, the direction of the suction port of the vacuum chamber was aligned with the traveling direction of the extruded sheet.

The surface of the laminate layer of the film was subjected to corona treatment (power density 20 W·min/m ² ). The film forming speed was 20 m/min. The formed film was trimmed at the edges and wound into a roll. Table 2 shows the evaluation results of the film of CPP1.

(CPP2)
As CPP2, an unstretched polypropylene film P1146 (thickness: 70 µm) manufactured by Toyobo Co., Ltd. was used.

[Examples and Comparative Examples]
<Preparation of Vacuum Insulating Material Exterior Laminate>
Aluminum foil (8079 material, thickness 40 μm) The biaxially stretched polyamide film obtained in Production Example 1 was laminated on one side, and the unstretched polyolefin film obtained in Production Example 2 was laminated on the opposite side of the aluminum foil. Ester-based adhesive obtained by mixing 33.6 parts by mass of the main agent (TM569, manufactured by Toyo-Morton Co., Ltd.), 4.0 parts by mass of the curing agent (CAT10L, manufactured by Toyo-Morton Co., Ltd.), and 62.4 parts by mass of ethyl acetate. A coating agent was applied so that the coating amount was 3.0 g/m ² , and laminated by dry lamination. All the biaxially stretched polyamide films and non-stretched polyolefin films were laminated with the longitudinal direction and the width direction aligned. The wound product was kept at 40° C. and aged for 3 days.

Further, when laminating a biaxially stretched polyester film as the base material layer 2 on the outside of the biaxially stretched polyamide film, after laminating the biaxially stretched polyester film and the biaxially stretched polyamide film in advance by the same method as described above, It was laminated on one side of aluminum foil. Next, an unstretched polyolefin film was laminated on the opposite side of the aluminum foil.
As the base material layer 2, the following films were used.
(PET1)
Biaxially oriented polyethylene terephthalate film (thickness: 16 μm) using petroleum-derived terephthalic acid as the dicarboxylic acid component and petroleum-derived ethylene glycol as the diol component
(PET2)
Biaxially oriented polyethylene terephthalate film (thickness 16 μm) using petroleum-derived terephthalic acid as the dicarboxylic acid component and biomass-derived ethylene glycol as the diol component

The combinations shown in Table 3 were used to fabricate vacuum heat insulating material exterior laminates for evaluation. Table 3 shows the results.

As shown in Table 3, the vacuum heat insulating material exterior laminates of Examples were excellent in cold formability even when the degree of biomass was increased.

On the other hand, the laminates of Comparative Examples 1, 2, and 5 used only conventionally used petroleum-derived films, so the degree of biomass was 0%, and the environmental load could not be reduced.
In the laminate of Comparative Example 3, the biomass content of the biaxially stretched polyamide film used is low, so the effect of reducing the environmental load is insufficient.
In the laminate of Comparative Example 4, the heat treatment temperature during the formation of the biaxially stretched polyamide film was high, and the puncture strength of the film was lowered, resulting in insufficient puncture strength of the laminate.

As described above, the vacuum insulation exterior laminate of the present invention is excellent in puncture resistance and can be suitably used for carbon-neutral vacuum insulation exterior laminate applications using biomass-derived raw materials.

Claims (9)

A laminate in which at least a substrate layer 1, an adhesive layer, a metal foil layer and a sealant layer are laminated in this order, wherein the substrate layer 1 is a biaxially stretched polyamide film satisfying the following (a) to (c) A vacuum insulation material exterior laminate.
(a) Thickness 8 to 30 μm
(b) The content of biomass-derived carbon measured by radioactive carbon (C14) is 1 to 30% relative to the total carbon in the base layer 1
(c) Puncture strength measured by JIS Z 1707 method is 0.7 N/μm or more 2. The vacuum heat insulating material according to claim 1, wherein the substrate layer 1 is a single-layer biaxially oriented polyamide film formed from a resin composition containing polyamide 6 and a polyamide whose raw material is at least partly derived from biomass. Exterior laminate. The base material layer 1 includes a layer (A layer) formed from a resin composition containing polyamide 6 and a polyamide at least part of which is derived from biomass, and a layer (A layer) containing polyamide 6, and at least part of the raw material is biomass. 2. The vacuum insulation exterior laminate according to claim 1, which is a biaxially stretched polyamide film comprising at least two layers (layer B) formed from a resin composition that does not contain the polyamide from which it is derived. The vacuum insulation material according to claim 2 or 3, wherein the polyamide at least part of which is derived from biomass is at least one polyamide selected from the group consisting of polyamide 11, polyamide 410, polyamide 610 and polyamide 1010. Exterior laminate. 5. The vacuum insulation exterior laminate according to claim 1, wherein the sealant layer is an unstretched polyolefin film. The stretched polyolefin film is an unstretched polyolefin film containing 70 to 95% by mass of a polypropylene resin and 5 to 30% by mass of a linear low-density polyethylene resin whose raw material is at least partly derived from biomass. Item 6. A laminate for vacuum heat insulating material exterior according to item 5. The vacuum of any one of claims 1 to 6, wherein the content of biomass-derived carbon by radiocarbon (C14) measurement in the sealant layer is 3-30% relative to the total carbon in the sealant layer. Laminate for thermal insulation exterior. The vacuum heat insulating material exterior according to any one of claims 1 to 7, wherein a base layer 2 having a thickness of 10 to 30 µm is further laminated on the surface of the base layer 1 opposite to the metal foil layer. laminate. 9. The vacuum insulation exterior laminate according to claim 8, wherein the base material layer 2 is a biaxially oriented polyester film.