JPH11270780A - Vacuum heat insulating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent heat insulating material by evacuating a core material-containing hollow section covered with a layered product having at least one layer mainly made of polyvinylidene chloride and one gas barrier resin composition layer made of a resin and an inorganic stratified compound respectively. SOLUTION: A copolymer of a vinylidene chloride monomer and various copolymerizable monomers is preferably used for a layer mainly made of polyvinylidene chloride. A clay mineral is used for an inorganic stratified compound, for example. Polysaccharide is preferably used for the resin of a gas barrier resin composition layer made of the resin and the inorganic stratified compound, for example. A core material is not limited in particular as far as it has a heat insulating property, and a communicating resin foam body is used, for example. The evacuating method of a hollow section is not limited in particular. When the gas barrier resin layer and the layer mainly made of polyvinylidene chloride are laminated, a layered product has at least one gas barrier resin layer and one layer mainly made of polyvinylidene chloride respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a vacuum heat insulating material.

[0002]

2. Description of the Related Art A method of evacuating the inside of a structure sealed with a container or an outer wrapping material formed of a gas barrier material to enhance the heat insulating effect has been conventionally known. A vacuum heat insulating material in which a core material is filled in the inside of the structure and evacuated is also known. In such a vacuum heat insulating material, the gas heat transfer is reduced by maintaining the inside at a high degree of vacuum to improve the heat insulating property.In order to maintain the heat insulating property for a long time, for example, the above-described structure is used. It is necessary to use a material having extremely excellent gas barrier properties for the body.

As such a material, a resin, particularly a thermoplastic resin, is preferable from the viewpoint of moldability, but PVDC (polyvinylidene chloride) or EVOH (ethylene-vinyl acetate copolymer) which is a typical example of a resin having excellent gas barrier properties is used. However, the gas barrier properties of the unified saponified product and the like are insufficient as a vacuum heat insulating material, and it has been difficult to maintain the heat insulating property of the obtained structure for a long period of time. Therefore, for the purpose of improving the gas barrier properties of the resin, for example, JP-A-63-279
No. 083, JP-A-63-233284,
A metal laminate in which an aluminum foil is laminated on a thermoplastic resin film is described.

[0004] However, a vacuum heat insulating material comprising the above-mentioned metal laminate can maintain a high degree of vacuum for a long period of time, but a metal such as aluminum has a high thermal conductivity (for example, aluminum has a thermal conductivity of about 200 W). / MK
Whereas, the polypropylene resin is about 0.23 W /
m · K, about 0.02 W / m · K in air), a so-called heat bridge in which heat moves along the metal part was generated, and the heat insulation performance was greatly reduced.

Although it has been considered to reduce the thickness of the metal layer for the purpose of suppressing the heat bridge, generally, when laminating a metal on a thermoplastic resin layer, a metal such as aluminum is vaporized once at a high temperature and the resin is laminated. To vapor-deposit on the surface of the layer or to separately create a metal foil by rolling or the like, and then laminate it to the resin layer, in these methods, when the thickness of the metal layer is reduced, many pinholes are generated, and the metal layer is provided. Despite this, the gas barrier properties decreased, resulting in a decrease in long-term heat insulation performance.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a resin composition layer composed of a resin and an inorganic layered compound has high gas barrier properties. The present inventors have found that by using a gas barrier layer in combination with a layer containing polyvinylidene chloride as a main component, it is possible to obtain a vacuum heat insulating material that has excellent thermal breakability and maintains heat insulating properties for a long period of time.

That is, the present invention relates to a core material-containing hollow covered with a laminate having at least one layer each of a layer mainly composed of polyvinylidene chloride and a gas barrier resin composition layer composed of a resin and an inorganic layered compound. It is intended to provide a vacuum heat insulating material obtained by evacuating a part. Hereinafter, the present invention will be described in detail.

BEST MODE FOR CARRYING OUT THE INVENTION

In the present invention, the layer mainly composed of polyvinylidene chloride is a layer composed of a resin composed mainly of vinylidene chloride monomer, and may be a layer composed of a polymer composed of only vinylidene chloride monomer. From the viewpoint of thermal stability during processing, a copolymer of a vinylidene chloride monomer and various copolymerizable monomers is more preferable. Examples of the copolymerizable monomer include acrylonitrile, vinyl chloride, vinyl acetate, (meth) acrylic acid ester, unsaturated ether, and styrene. Examples thereof include vinylidene chloride-vinyl chloride copolymer and vinylidene chloride-methyl acrylate copolymer. And so on.

The thickness of the layer containing polyvinylidene chloride as a main component is not particularly limited, but is usually 1 to 200 μm.
The thickness is preferably 10 μm or more from the viewpoint of the effect, and more preferably 50 μm or less from the viewpoint of operability in manufacturing the laminate.

The layer containing polyvinylidene chloride as a main component may contain various additives such as a plasticizer, an ultraviolet ray inhibitor and a crosslinking agent as long as the effects of the present invention are not impaired.

The inorganic layered compound used in the present invention includes:
An inorganic compound in which unit crystal layers are stacked on each other to have a layered structure. The layered structure refers to a structure in which planes in which atoms are strongly bonded by covalent bonds or the like and densely arranged are stacked substantially in parallel by a weak bonding force such as van der Waals force. As the inorganic layered compound, the aspect ratio measured by the method described below is preferably 50 or more and 5000 or less, more preferably 100 or more, from the viewpoints of gas barrier properties, economic efficiency and availability of the obtained film laminate. It is particularly preferable that the number be 3000 or more and 3000 or less. Further, from the viewpoint of the moldability of the film laminate described below, the particle diameter measured by the method described below is preferably 5 μm or less, more preferably 3 μm or less.

Specific examples of such an inorganic layered compound include:
Graphite, phosphate derivative type compound (zirconium phosphate compound), chalcogenide [Group IV (Ti,
Zr, Hf), a dichalcogen compound of group V (V, Nb, Ta) and Group VI (Mo, W), the formula MX _2. Here, X is a chalcogen (S, Se, Te)
Is shown. And clay-based minerals.

The aspect ratio (Z) of the inorganic layered compound used in the present invention is a ratio determined from the relationship of Z = L / a. Here, L is the particle size (volume-based median diameter) of the inorganic layered compound in the dispersion obtained by the particle size measurement method by the diffraction / scattering method described above, and a is the unit thickness of the inorganic layered compound. is there. The “unit thickness a” is a value determined based on the measurement of the inorganic stratiform compound alone by a powder X-ray diffraction method or the like described later. More specifically, as shown schematically in the graph of FIG. 1 in which the horizontal axis indicates 2θ and the vertical axis indicates the intensity of the X-ray diffraction peak, it corresponds to the lowest angle peak among the observed diffraction peaks. From the angle θ
gg (nλ = 2D sin θ, n = 1, 2, 3,...)
) Is defined as “unit thickness a” (for details of the powder X-ray diffraction method, see, for example, Jiro Shiokawa, “Guidance for Instrumental Analysis (a)”, p. 69 (1985)
Year) can be referred to issued by Kagaku Doujinsha).

When the resin composition obtained by removing the solvent from the dispersion is subjected to powder X-ray diffraction, it is usually possible to determine the interplanar spacing d of the inorganic layered compound in the resin composition. More specifically, as shown in the graph of FIG. 2 in which the horizontal axis indicates 2θ and the vertical axis indicates the intensity of the X-ray diffraction peak,
Of the diffraction peaks observed on the lower angle (larger interval) side than the diffraction peak position corresponding to the above “unit thickness a”, the interval corresponding to the peak at the lowest angle side is referred to as “plane interval d” (a <D). As schematically shown in the graph of FIG. 3, when it is difficult to detect the peak corresponding to the “surface distance d” by overlapping with a halo (or background), the baseline on the lower angle side than 2θd is detected. The area of the portion excluding is set as a peak corresponding to the “surface distance d”. Here, “θd” is “(unit length a) +
(The width of a single resin chain) "(for details of the method of determining the spacing d, see, for example, Shuichi Iwami et al.," Encyclopedia of Clay ", p. 35 or less and p. 271 or less,
1985, Asakura Shoten Co., Ltd. can be referred to).

As described above, the “integrated intensity” of the diffraction peak (corresponding to the plane spacing d) observed in the powder X-ray diffraction of the resin composition is the same as the reference diffraction peak (corresponding to “plane spacing d”). The relative ratio to the integrated intensity is preferably 2 or more (more preferably 10 or more). Usually, the above-mentioned surface distance d
And the value of k = (da) (when converted to “length”) is equal to or larger than the width of a single resin chain constituting the resin composition. (K = (d
-A) ≧ resin single-chain width). Such “width of single resin chain” can be determined by simulation calculation or the like (for example, “Introduction to Polymer Chemistry”, 103-1)
10, page 1981, Kagaku Doujin), and in the case of polyvinyl alcohol, it is 4 to 5 angstroms (2 to 3 angstroms for water molecules).

It is extremely difficult to directly measure the "true aspect ratio" of the inorganic layered compound in the resin composition. The above aspect ratio Z = L / a is not always equal to the “true aspect ratio” of the inorganic layered compound in the resin composition.
It is appropriate to approximate “true aspect ratio” with

The relation a <d is established between the plane distance d of the resin composition obtained by the powder X-ray diffraction method and the “unit thickness a” obtained by the powder X-ray diffraction measurement of the inorganic layered compound alone. And the value of (da) is less than the value of resin 1 in the composition.
If the width of the main chain or more, in the resin composition,
The resin is inserted between the layers of the inorganic layered compound. Therefore, to approximate the thickness of the inorganic layered compound in the resin composition by the above “unit thickness a”, that is, the “true aspect ratio” in the resin composition, The approximation with the "aspect ratio Z" has sufficient validity.

As described above, it is extremely difficult to measure the true particle size in the resin composition. However, the particle size of the inorganic stratiform compound in the resin is determined in the dispersion (resin / inorganic stratiform compound / solvent). Can be considered to be quite close to the particle size of the inorganic layered compound. However, since the particle diameter L in the dispersion obtained by the diffraction / scattering method is considered to be very unlikely to exceed the major axis Lmax of the inorganic layered compound, the true aspect ratio (Lmax / a) of the present invention is not so high. The probability of being lower than the “aspect ratio Z” used in (Lmax / a <Z) is theoretically quite low.

From the above two points, it is considered that the definition Z of the aspect ratio used in the present invention has sufficient validity. In the present specification, “aspect ratio” or “particle size” means “aspect ratio Z” defined above or “particle size L determined by a diffraction / scattering method”.

From the viewpoint of the aspect ratio as described above,
As the inorganic layered compound, an inorganic layered compound which swells or cleaves in a solvent is preferably used. The degree of swelling or cleavage of the inorganic layered compound used in the present invention in a solvent can be evaluated by the following swelling and cleavage test. The degree of swelling of the inorganic stratiform compound is preferably about 5 or more (more preferably about 20 or more) in the following swellability test. On the other hand, the degree of cleavage of the inorganic layered compound is preferably about 5 or more (more preferably about 20 or more) in the following cleavage test. However, in these measurements, a solvent having a density smaller than the density of the inorganic layered compound is used as the solvent. For example, when the inorganic layered compound is a natural swellable clay mineral, it is preferable to use water as the solvent.

<Swellability test>: 2 g of the inorganic layered compound was added to 100 mL of a solvent (for example, using a 100 mL graduated cylinder as a container), stirred, and allowed to stand at 23 ° C. for about 1 day. The volume of the former (inorganic layered compound dispersed layer) is read from the scale of the interface. It can be said that the larger the value is, the higher the swelling property is.

<Cleaving test>: 30 g of inorganic layered compound
Was slowly added to 1500 mL of a solvent, sufficiently dispersed with a dispersing machine (23 ° C.), 100 mL of the dispersion was taken, and allowed to stand for about 1 hour, and the volume of the inorganic layered compound dispersed layer was measured from the scale at the interface with the supernatant in the same manner as described above. I Read. It can be said that the larger this value is, the higher the cleavage is.

As the inorganic layered compound which swells or cleaves in a solvent, a clay mineral which swells or cleaves in a solvent can be suitably used. Clay-based minerals generally have a two-layer structure having an octahedral layer with aluminum or magnesium as the central metal on top of a silica tetrahedral layer, and a silica tetrahedral layer containing aluminum or magnesium. It is classified into a type having a three-layer structure in which an octahedral layer serving as a central metal is sandwiched from both sides.

Examples of the former include kaolinites and antigolites, and examples of the latters include smectites, vermiculites and the like depending on the number of interlayer cations.
Mica and the like can be mentioned.

More specifically, kaolinite, dickite, nacrite, halloysite, antigolite, chrysotile, pyrophyllite, montmorillonite, hectorite, tetrasilyl mica, sodium teniolite, muscovite, margarite, talc, vermiculite Phlogopite, zansophilite, chlorite and the like.

As a solvent for swelling the inorganic layered compound, for example, in the case of a natural swellable clay mineral, water, alcohols such as methanol, dimethylformamide, dimethylsulfoxide, acetone and the like can be mentioned. More preferred.

Examples of the resin used in the gas barrier resin composition layer comprising the resin of the present invention and the above-mentioned inorganic layered compound include polyvinyl alcohol (PVA), modified polyvinyl alcohol (modified PVA), and ethylene-vinyl alcohol copolymer. (EVOH), modified ethylene-
Vinyl alcohol copolymer (modified EVOH), polyvinylidene chloride (PVDC), polyacrylonitrile (PA
N), polysaccharides, polyacrylic acid and esters thereof are preferred.

In a preferred example, the weight percentage of the hydrogen bonding group or the ionic group per unit weight of the resin is 2%.
A high hydrogen bonding resin satisfying a ratio of 0% to 60% is exemplified. More preferred examples include those in which the weight percentage of the hydrogen bonding group or the ionic group per unit weight of the high hydrogen bonding resin satisfies the ratio of 30% to 50%. Examples of the hydrogen bonding group of the high hydrogen bonding resin include a hydroxyl group, an amino group, a thiol group, a carboxyl group, a sulfonic acid group, a phosphoric acid group, and the like, and examples of the ionic group include a carboxylate group, a sulfonic acid ion group, and a phosphoric acid group. Examples include an ionic group, an ammonium group, and a phosphonium group.

Among the hydrogen bonding groups or ionic groups of the high hydrogen bonding resin, more preferred are a hydroxyl group, an amino group, a carboxyl group, a sulfonic acid group, a carboxylate group, a sulfonic acid ionic group, an ammonium group,
And the like.

As specific examples, for example, polyvinyl alcohol, an ethylene-vinyl alcohol copolymer having a vinyl alcohol fraction of 41 mol% or more, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, amylose, amylopectin, pullulan, curdlan, xanthan Polysaccharides such as, chitin, chitosan, cellulose, pullulan, chitosan, etc., polyacrylic acid, sodium polyacrylate, polybenzenesulfonic acid, sodium polybenzenesulfonate, polyethyleneimine, polyallylamine, its ammonium salt polyvinyl thiol, poly Glycerin, and the like.

More preferred high hydrogen bonding resins include polyvinyl alcohol and polysaccharides.
Polyvinyl alcohol is obtained by hydrolyzing (saponifying) an acetic ester portion of a vinyl acetate polymer, and is precisely a copolymer of vinyl alcohol and vinyl acetate. Here, the saponification ratio is preferably 70% or more in terms of mole percentage, and more preferably 85% or more. The degree of polymerization is preferably 100 or more and 5000 or less.

[0032] Polysaccharides are biopolymers synthesized in biological systems by polycondensation of various monosaccharides, and here also include those chemically modified based on them. Examples include cellulose and cellulose derivatives such as hydroxymethylcellulose, hydroxyethylcellulose and carboxymethylcellulose, amylose, amylopectin, pullulan, curdlan, xanthan, chitin, chitosan and the like.

In the present invention, the composition ratio (weight ratio) of the inorganic layered compound and the resin is (inorganic layered compound / resin) in a weight ratio of 5/95 to 90/10 from the viewpoint of heat insulating effect and moldability.
Is preferred, and more preferably in the range of 5/95 to 50/50.

From the viewpoint of maintaining the heat insulating properties of the obtained vacuum heat insulating material over a long period, the gas barrier resin composition layer 2
The oxygen permeability at 3 ° C. and 50% RH is 0.2 cc / m ² · d
ay · atm or less is preferable, 0.1 cc / m ² · day · atm or less is more preferable, and 0.0001 cc / m ² · day · atm or less is particularly preferable. The oxygen permeability at 23 ° C may be measured directly,
Oxygen permeability at high temperature was measured and 2
It may be obtained by extrapolating to 3 ° C.

The method for producing the resin composition layer comprising the above-mentioned inorganic layered compound and a resin is not particularly limited, but from the viewpoint of the dispersibility of the inorganic layered compound in the obtained gas barrier resin composition layer and the ease of operation. For example, a method in which a liquid in which a resin is dissolved and a dispersion in which an inorganic layered compound is swollen or cleaved in advance is mixed, and then the solvent is removed (method 1). To remove the solvent (Method 2), adding the inorganic stratiform compound to the liquid in which the resin is dissolved, removing the solvent (Method 3) by swelling or cleaving the dispersion, and removing the resin and the inorganic stratiform compound by heat. A method such as a kneading method (method 4) can be exemplified. The former three are preferably used from the viewpoint that a large aspect ratio of the inorganic layered compound can be easily obtained. Also,
In the former three, treatment using a high-pressure dispersion device is preferable from the viewpoint of dispersibility of the inorganic layered compound.

As a high-pressure dispersion device, for example, Micro
There is an ultra-high pressure homogenizer (trade name: Microfluidizer) manufactured by Fluidics Corporation or a Nanomizer manufactured by Nanomizer. Other examples include a Manton-Gaulin type high-pressure dispersion device, such as a homogenizer manufactured by Izumi Food Machinery.

Further, as long as the effects of the present invention are not impaired, various additives such as a crosslinking agent, an ultraviolet absorber, a coloring agent and an antioxidant may be mixed in the resin composition.

The vacuum heat insulating material of the present invention has a core material-containing hollow portion covered with a laminate having at least one layer containing the above-mentioned polyvinylidene chloride-based layer and at least one gas barrier resin composition layer. In addition, by evacuating the inside of the hollow portion, the heat insulating effect is further enhanced.

The hollow portion may be entirely covered with the laminate, or may have a region not covered with the laminate, but the hollow portion is covered with the laminate. If there is a region that is not covered, cover the region with another gas barrier material, or the area of the region should be negligible from the viewpoint of gas barrier properties with respect to the area covered by the laminate. Is preferred from the viewpoint of maintaining heat insulation.

The core material to be used is not particularly limited as long as it has heat insulating properties. For example, JIS R
The thermal conductivity as measured by 2618 is 0.1 W / m ·
Those below K are preferred. Specific examples of the core material include pearlite powder, silica powder, precipitated silica powder, glass wool, rock wool, and a communicating resin foam.
Particularly, a 100% communicating urethane foam is more preferable from the viewpoint of lightness.

If necessary, a so-called getter material having a gas-adsorbing property may be used in combination, or the getter material may be used as a core material.

Further, in the hollow portion of the vacuum heat insulating material of the present invention,
It may have a hollow structure. The shape of the hollow structure is not particularly limited, and includes a rectangular parallelepiped, a cube, a sphere, and the like.
In light of heat insulation, the thickness of the wall forming the hollow structure is preferably equal to or less than 10 mm, more preferably equal to or less than 5 mm,
Particularly preferred is 1 mm or less. The constituent material is not particularly limited, but is preferably made of resin from the viewpoint of the heat insulating property of the obtained vacuum heat insulator.

Examples of the resin include low-density or high-density polyethylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, polypropylene, and ethylene-acetic acid. Polyolefin resins such as vinyl copolymer, ethylene-methyl methacrylate copolymer, ionomer resin, polyester resins such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, nylon-6, nylon-
6,6, meta-xylene diamine-adipic acid condensation polymer,
Amide resins such as polymethyl methacrylimide, acrylic resins such as polymethyl methacrylate, polystyrene, styrene-acrylonitrile copolymer, styrene-acrylonitrile-butadiene copolymer, styrene and acrylonitrile resins such as polyacrylonitrile, cellulose triacetate , Cellulose-based hydrophobic resins such as cellulose diacetate, halogen-containing resins such as polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, and Teflon; hydrogen-bonding resins such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, and cellulose derivatives , Liquid crystalline polymers such as liquid crystal polyester resin, polycarbonate resin, polysulfone resin, polyethersulfone resin, polyetheretherketone resin, polyphenyleneoxy Resins, polymethylene oxide resins,
Examples include engineering plastic resins such as aramid resins, urethane resins, phenol resins, and epoxy resins.

Further, the hollow structure may have the core material and / or the getter material as described above therein.

The laminate of the present invention may have a heat-sealing layer or a base material layer in addition to the layer mainly composed of polyvinylidene chloride and the gas barrier resin composition layer. A laminate composed of a composition layer, a layer mainly containing polyvinylidene chloride, and a heat-sealing layer can be exemplified, but the layer configuration is not particularly limited.

The method of evacuating the hollow portion covered with the laminate is not particularly limited. For example, the laminate is formed into a bag by heat fusion or the like, and a core material or the like is placed in the bag. Examples of the method include a method of evacuating the inside of the bag-shaped material and then sealing it, a method of providing a vacuum suction hole in the hollow structure covered with the laminate, and sealing the suction hole after evacuation.

The pressure in the hollow portion covered with the laminate of the present invention is usually 1 Torr or less. From the viewpoint of the heat insulating effect, 0.1 Torr or less is more preferable, and 0.01
rr or less is particularly preferred.

Other than the above-mentioned gas barrier resin composition layer and the layer containing polyvinylidene chloride as a main component, a layer such as a base layer may be used. Examples of such a layer include aluminum foil and steel foil. Metal thin film layer, inorganic thin film layer,
There is no particular limitation on the resin layer and the like. As the resin layer, for example, polyethylene (low density, high density), ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-octene copolymer, polypropylene, ethylene-vinyl acetate Copolymer, ethylene-methyl methacrylate copolymer, polyolefin resin such as ionomer resin, polyester resin such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, nylon-6, nylon-6,6, meta-xylene diamine- Condensed polymers of adipic acid, amide resins such as polymethyl methacrylimide, acrylic resins such as polymethyl methacrylate, polystyrene, styrene-acrylonitrile copolymer, styrene-acrylonitrile-butadiene copolymer , Styrene and acrylonitrile resins such as polyacrylonitrile, cellulose triacetate, hydrophobic cellulose-based resin such as di-cellulose acetate, polyvinyl chloride,
Halogen-containing resins such as polyvinylidene chloride, polyvinylidene fluoride, and Teflon, hydrogen bonding resins such as polyvinyl alcohol, ethylene-vinyl alcohol copolymer, and cellulose derivatives, polycarbonate resins, polysulfone resins, polyethersulfone resins, and polyether ethers A layer made of engineering plastic resin such as ketone resin, polyphenylene oxide resin, polymethylene oxide resin, and liquid crystal polyester resin, a layer made of biaxially stretched polypropylene, polyethylene terephthalate, nylon, etc., and a polyvinylidene chloride called K coat. Coated biaxially stretched layers of polypropylene, polyethylene terephthalate, nylon, etc., aluminum-deposited film, alumina-deposited film, silica-deposited Various consisting deposited film layer and the liquid crystal polyester resin such beam, the layer made of aramid resin can be exemplified.

When a heat-sealing layer is provided on the laminate, the resin used for the heat-sealing layer may be polyethylene (low-density, high-density) from the viewpoint of desorption such as heat sealing strength and resin odor. Ethylene-vinyl alcohol copolymer,
Ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene-octene copolymer, polypropylene, ethylene-vinyl acetate copolymer, Polyethylene resins such as ethylene-methyl methacrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-acrylic acid copolymer, ionomer resin, polyamide resins such as nylon 6, nylon 66, and acrylonitrile / butadiene / styrene Examples include polymers, acrylonitrile / styrene copolymers, acrylonitrile copolymers, and polyacrylates such as polymethyl methacrylate.

As a method of laminating a gas barrier resin layer, a layer containing polyvinylidene chloride as a main component, and a base material layer if necessary, a layer containing polyvinylidene chloride as a main component or another layer may be used. Into a film or sheet in advance,
A coating method comprising applying and drying a coating solution obtained by dissolving or dispersing a composition comprising a resin and an inorganic layered compound in the film or sheet in a solvent that swells the inorganic layered compound as described above, and performing a heat treatment. A method of laminating a film made of the composition later can be exemplified. In this way, a laminate having at least one gas barrier resin layer and at least one layer containing polyvinylidene chloride as a main component can be obtained.

When a layer containing polyvinylidene chloride as a main component is formed into a film in advance, a conventional extrusion molding method such as a T-die, a method of coating another resin film in an aqueous emulsion or solution state, and the like can be exemplified. The other resin film to be coated is preferably uniaxially or biaxially stretched from the viewpoint of gas barrier properties.

The layer on which the gas barrier resin layer is laminated may be a layer containing polyvinylidene chloride as a main component or another layer such as a base material layer. Examples of a method of laminating a layer containing polyvinylidene chloride as a main component and another layer include a usual coextrusion method, an extrusion lamination method, a dry lamination method, and the like.

Examples of the coating method include a direct gravure method, a reverse gravure method and a microgravure method, a roll coating method such as a two roll beat coating method, a bottom feed three reverse coating method, and a doctor knife method, a die coating method, and a dip coating method. Methods, bar coating methods, and coating methods combining these methods.

The method of laminating the heat-sealing layer is not particularly limited. For example, a method of dry laminating the above-mentioned other layer, a layer mainly containing polyvinylidene chloride, or a gas-barrier resin composition layer And the like are preferred examples. Further, each layer may be subjected to a treatment such as a corona treatment, an ozone treatment, an electron beam treatment, or an anchor coat agent from the viewpoint of the adhesion strength between the layers.

Further, the vacuum heat insulating material of the present invention may be provided with a detector for checking the degree of vacuum inside as required.

Each of the layers may contain various commercially available additives such as an ultraviolet absorber, a cross-linking agent, a coloring agent, and an antioxidant, which are usually added to the resin, as long as the effects of the present invention are not impaired. Is also good.

The vacuum heat insulating material of the present invention has excellent heat insulating performance,
Refrigerated (10 ° C or less) refrigerator or refrigerator (0 ° C or less)
It can be used for refrigeration or freezing use as a heat insulating material for walls such as a refrigerator or a freezer compartment. Further, the vacuum heat insulating material of the present invention can be used for building materials used as heat insulating materials for ceilings, walls, floors and the like.

[0058]

The vacuum heat insulating material of the present invention has excellent heat insulating properties as compared with conventional ones and maintains the heat insulating properties for a long period of time. Further, the vacuum heat insulating material of the present invention can be used for various applications that require heat insulation such as cold insulation, heat insulation (for example, refrigerators, freezers, cool cars, car ceilings, batteries, refrigerated or refrigerated boats, heated containers, refrigerated or refrigerated displays. Case,
Portable cooler, cooking warm case, vending machine, solar water heater, floor heating, underfloor, wall or inside the wall, ceiling, attic, building materials, piping of hot or cooling water, conduit for transferring low-temperature fluid In addition, it can be suitably used as a heat insulator for plant equipment, clothing, bedding, etc.).

[0059]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples.

The methods for measuring various physical properties are described below. [Measurement of Thermal Conductivity] The measurement was performed according to JIS A1412.

[Oxygen permeability measurement] Oxygen permeability measuring device (O
X-TRAN100, manufactured by MOCON) at 23 ° C, 5
The oxygen permeability was measured at 5 ° C. and 80 ° C. In addition,
The oxygen permeability at 55 ° C. and 80 ° C. was measured by placing a measurement sample in a constant temperature chamber set at a predetermined temperature.

[Heat Sealing Conditions] Temperature 208 ° C., time 0.5 second, heat seal width 10 mm (heat sealer:
FUJI IMPULSE T230: FUJI IM
PULSE CO. LTD).

[Thickness Measurement] A thickness of 0.5 μm or more was measured with a digital thickness gauge. Less than 0.5 μm is determined by a gravimetric analysis method (the measured value of the weight of a film having a certain area is divided by the area and further divided by the specific gravity of the composition), or the laminate of the gas barrier resin composition layer and the substrate layer In some cases, the ratio of the resin composition layer of the present invention to the base material is determined from the elemental analysis method (the specific inorganic element analysis value of the laminate (derived from the composition layer) and the specific element fraction of the inorganic layered compound alone). According to).

[Measurement of Particle Size] Ultrafine particle size analyzer (BI-
90, manufactured by Brookhaven) at a temperature of 25 ° C. and in a water solvent. The center diameter determined by the photon correlation method based on the dynamic light scattering method was defined as the particle diameter L.

[Calculation of Aspect Ratio] X-ray diffractometer (XD
-5A (manufactured by Shimadzu Corporation), the diffraction measurement of the inorganic layered compound alone and the resin composition by the powder method was performed. Thereby, the plane spacing (unit thickness) a of the inorganic layered compound was determined, and further, from the diffraction measurement of the resin composition, it was confirmed that there were portions where the plane spacing of the inorganic layered compound was widened. Using the particle diameter L obtained by the above method, the aspect ratio Z
Was determined by the equation of Z = L / a.

[Coating liquid 1] Dispersion pot (trade name: Despa MH)
-L, manufactured by Asada Tekko Co., Ltd.) and ion-exchanged water (0.7 μS / cm)
3551 g) and 200 g of polyvinyl alcohol (PVA117H; manufactured by Kuraray Co., Ltd., degree of saponification; 99.6%, degree of polymerization: 1700), and under low-speed stirring (1500 rpm)
m, the peripheral speed is 4.10 m / min) and the temperature is raised to 95 ° C.
Stir for hours to dissolve. Next, after lowering the temperature to 60 ° C. while stirring, natural montmorillonite (Kunipia G;
100 g of Kunimine Industries Co., Ltd.) as a powder was added, and after confirming that montmorillonite had substantially precipitated in the solution, high-speed stirring was performed (3100 rpm, peripheral speed 8.47 m / min).
Was carried out for 90 minutes to obtain a resin composition mixed solution (A) having a total solid content of 8 wt%. The mixed solution (A) was cast into a film, and X-ray analysis was performed. The bottom distance from the peak was 41.2 angstroms, indicating that the cleavage was sufficiently cleaved. The particle size of the natural montmorillonite (Kunipia F) determined by dynamic light scattering was 560 nm, the a value obtained from powder X-ray diffraction was 1.2156 nm, and the aspect ratio (Z) was 461.

Further, a silicone-based surfactant SH37
A liquid to which 0.38 g of No. 46 (manufactured by Dow Corning Toray Co., Ltd.) was added was used as Coating Liquid 1.

Example 1 A polyvinylidene chloride film having a thickness of 14 μm (Saran UB, 15 μ, Kureha Chemical Industry)
Co., Ltd.) and an anchor coat agent (Adcoat AD335 /
CAT10 = 15/1 (weight ratio): Toyo Morton Co., Ltd.
Gravure coating (test coater; Yasui Seiki Co., Ltd.)
Manufacture: microgravure coating method, coating speed 3 m / min, drying temperature 80 ° C.). The dry thickness of the anchor coat layer was 0.15 μm. The coating liquid 1 was coated on the anchor coat layer by a gravure coating method (test coater; manufactured by Yasui Seiki Co., Ltd .: microgravure coating method, coating speed 6 m / min, drying temperature 100 ° C.). The dry thickness of the coating layer was 0.5 μm.

Then, the coating layer obtained above was subjected to a surface corona treatment using a urethane-based adhesive (Eunoflex J3: manufactured by Sanyo Chemical Co., Ltd.).
(KF101: thickness 40 μm) was dry-laminated on the coating layer to obtain a laminated film. Then, the gas barrier properties of the laminated film were measured (Table 1).

Using the two laminated films obtained above, the three sides of the LLDPE layer, which is the inner layer, were thermally fused by 250 mm ×
A 250 mm bag is made. Then, a 100% communicating urethane foam (average cell diameter of 75
μ, manufactured by Kurabo Industries Co., Ltd.), and the inside of the bag is reduced to 0.01 Torr by a vacuum sealer (manufactured by NPC).
The other side of the bag is heat-sealed to obtain a vacuum heat insulating material. The thermal conductivity of the obtained vacuum heat insulating material is extremely low, and the heat insulating property during aging is extremely low.

Comparative Example 1 Polyvinylidene Chloride Film
(Saran UB, manufactured by Kureha Chemical Co., Ltd., 15μ) is dry-laminated on a biaxially stretched polypropylene film (thickness: 20μ) using a urethane-based adhesive (Eunoflex J3: manufactured by Sanyo Chemical Co., Ltd.), and further polyvinylidene chloride LL with surface corona treatment on the side opposite to the side where the film was laminated
DPE (manufactured by Seki-Fill Corporation: KF101: thickness 40 μm)
Was dry-laminated to obtain a laminated film. The oxygen permeability of the laminated film was measured. (Table 1)

Further, a vacuum heat insulating material can be obtained under the same conditions as in Example 1, but the heat insulating property is significantly reduced by aging.

[0073]

[Table 1]

[Brief description of the drawings]

FIG. 1 shows the X-ray diffraction peaks of an inorganic layered compound,
It is a graph which shows the relationship with the "unit thickness a" of this compound typically.

FIG. 2 is a graph showing X of a resin composition containing an inorganic layered compound;
4 is a graph schematically showing a relationship between a line diffraction peak and “plane spacing d” of the composition.

FIG. 3 is an X-ray diffraction peak of a resin composition when a peak corresponding to “plane spacing d” overlaps a halo (or background) and is difficult to detect;
It is a graph which shows typically the relationship with the "plane spacing d" of this composition. In this figure, the area of the portion excluding the base line on the lower angle side than 2θd is set as the peak corresponding to “surface interval d”.

Claims (6)

[Claims] 1. A layer mainly comprising polyvinylidene chloride,
A vacuum heat insulating material obtained by evacuating a core material-containing hollow portion covered with a laminate having at least one gas barrier resin composition layer composed of a resin and an inorganic layered compound. 2. The temperature of the gas barrier resin composition layer at 23 ° C. and 50 ° C.
The vacuum heat insulating material according to claim 1, wherein the oxygen permeability at% RH is 0.1 cc / m ² · day · atm or less. 3. An inorganic layered compound having an aspect ratio of 50 to 5.
The vacuum heat insulating material according to claim 1 or 2, wherein 4. An inorganic layered compound having an aspect ratio of 200 to 200.
The vacuum heat insulating material according to claim 1, wherein the number is 3,000. 5. The vacuum heat insulating material according to claim 1, which is used for refrigeration or freezing. 6. The vacuum heat insulating material according to claim 1, which is used for building materials.