JP2011012395A - Composite heat insulating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite heat insulating material which has satisfactory heat insulating performance, while overcoming, for example, an adverse effect caused by kneading a heat-ray shielding material into a heat insulating material.SOLUTION: Characteristically, this composite heat insulating material is constituted by stacking a plurality of heat insulating material layers and heat-ray shielding material layers arranged among the heat insulating material layers. Preferably, the number of the heat insulating material layers and that of the heat-ray shielding material layers are not limited; and the heat-ray shielding material layers are arranged among all the heat insulating material layers, respectively. However, the composite heat insulating material can also be provided with the heat insulating materials in which the heat-ray shielding material layer is not arranged between the heat insulating material layers.

Description

  The present invention relates to a composite heat insulating material having a heat ray shielding layer and suppressing heat conduction.

  In recent years, energy saving properties are required from the viewpoint of global warming, and a higher heat resistance value is required as a heat insulating material used for buildings and the like, and therefore, there is an increasing demand for heat insulating materials with better heat insulating performance. Conventionally, a heat insulating material obtained by foaming a plastic resin is widely known. Such a heat insulating material is used as a heat insulating material for buildings and the like because it is lightweight and excellent in heat insulating performance.

  For example, styrene resin foams are mainly made of chlorofluorocarbons, which are typical foaming agents in the production process, and contain chlorofluorocarbon gases with low thermal conductivity in the foam bubbles. Thermal conductivity can be kept low. However, chlorofluorocarbons may destroy the ozone layer and cause global warming, which is not preferable for the global environment, and its use is strictly regulated.

  Therefore, for example, heat conduction of the resin foam can be achieved by kneading the resin foam with a heat ray shielding (reflection / absorption) material such as aluminum powder, silver powder, graphite powder, carbon black, mica, silica, calcium carbonate or titanium oxide. Techniques for reducing the rate have been proposed (Patent Documents 1 and 2). Since these heat ray shielding materials have high infrared reflectance or infrared absorption rate, it is possible to reduce the infrared transmittance of the styrene resin.

  Further, a composite heat insulating material has been proposed in which a sheet-like material made of an aluminum foil or an aluminum vapor-deposited plastic film is bonded to the surface of a heat insulating material (flat plate shape) (Patent Document 3). This composite heat insulating material is used so that the sheet-like material joined to the heat insulating material faces the outdoor side. When an external heat insulating structure provided with an air layer of a building is formed using this heat insulating material, the heat insulating performance can be improved by a heat shielding effect such as a bonded aluminum foil.

Japanese Unexamined Patent Publication No. 63-183941 Japanese National Publication No. 04-502173 JP 2009-30344 A

  However, when the heat ray shielding material used in Patent Documents 1 and 2 is added to a styrene resin and foamed, the heat ray shielding material becomes a core and the bubbles generated are significantly reduced, and the foam density is high. As a result, the cost increases. Moreover, the cross-sectional size required for the product may not be ensured.

  In addition, when a black heat ray shielding material such as graphite powder or carbon black is used, the color of the foam may become dark depending on the amount of use. In this case, for example, when a foam board used as a heat insulating material is brought into a building site and temporarily stored outdoors, infrared absorption easily occurs due to the influence of solar radiation, the surface temperature of the foam rises, and foaming occurs. The body may shrink or warp.

  Therefore, in order to improve the heat insulating performance of the heat insulating material without causing these side effects, it is hoped that the amount of the heat ray shielding material described above is eliminated or suppressed and the heat insulating performance is improved by other methods. It is rare.

  Furthermore, in the case of a composite heat insulating material in which a heat ray reflecting material (heat shielding material) such as an aluminum foil is joined to the surface of the heat insulating material as in Patent Document 3, the heat ray reflecting material exhibits a heat shielding effect. An air layer is necessarily required on the surface, and the effect is not exhibited in a usage form in which there is no air layer. In addition, aluminum foil, etc. present on the surface of the heat insulating material has low frictional resistance, so when using it for the problem of slipping during handling, especially for heat insulation of the roof, a person rides on the heat insulating material. There is a risk of sliding down.

  As a result of intensive studies to solve the above problems, the present inventors have found a composite heat insulating material having excellent heat insulating performance while solving the above problems, and completed the present invention. That is, the present invention provides the following composite heat insulating material.

[1] A composite heat insulating material obtained by laminating a plurality of heat insulating material layers and a heat ray shielding material layer disposed between the heat insulating material layers.

[2] The composite heat insulating material according to [1] above, wherein a layer of a heat ray shielding material is not disposed on a surface layer of the composite heat insulating material.

[3] The composite heat insulating material according to [1] or [2], wherein the heat insulating material is made of a resin foam.

[4] The composite heat insulating material according to any one of [1] to [3], wherein the resin foam does not contain a heat ray shielding material.

[5] The composite heat insulating material according to any one of [1] to [4], wherein the cell diameter of the resin foam is 0.1 mm to 0.8 mm.

[6] The composite heat insulating material according to any one of [1] to [5], wherein the layers of the heat ray shielding material are arranged at intervals of 1 mm or more.

  According to a preferred embodiment of the present invention, since it has excellent heat insulation performance without kneading a heat ray shielding material in particular, for example, the problem of bubble reduction by kneading the heat ray shielding material, graphite powder or carbon black The problem of shrinkage or warping of the foam due to the addition of a black heat ray shielding material such as styrene resin can be solved. Moreover, according to the preferable aspect of this invention, since the heat ray shielding materials, such as aluminum foil, are unnecessary on the surface of a composite heat insulating material, the restrictions on use that an air layer must be provided in the surface can be eliminated. .

  The composite heat insulating material according to the present invention is a composite heat insulating material formed by laminating a plurality of heat insulating material layers and a heat ray shielding material layer disposed between the heat insulating material layers. There is no limitation on the number of layers of the heat insulating material and the number of layers of the heat ray shielding material. Moreover, although it is preferable that the layer of a heat ray shielding material is arrange | positioned between all the heat insulating material layers, there may exist heat insulating materials in which the layer of a heat ray shielding material is not arrange | positioned between layers.

  Moreover, it is preferable that the composite heat insulating material which concerns on this invention arrange | positions the layer of a heat ray shielding material at a 1 mm or more space | interval, for example by making the thickness of each layer of a heat insulating material into 1 mm or more. More preferably, the interval is 3 mm or more, and still more preferably 5 mm or more. Here, if the thickness of the heat insulating material is less than 1 mm, it is very weak in strength and it is difficult to obtain good smoothness. For example, when used as a spherical heat insulating material, a bendable composite heat insulating material is effective. In that case, a bendable thickness is selected according to the material of the heat insulating material.

The material used for the layer of the heat insulating material is not particularly limited, but a material that is lightweight and excellent in heat insulating properties and pressure resistance is preferable. For example, a resin foam is preferable. Specifically, for example, a synthetic resin foam having closed cells such as a polystyrene resin foam, a polyethylene resin foam, a polypropylene resin foam, a polyurethane resin foam, and a phenol resin foam is preferable. In particular, an extruded polystyrene foam heat insulating plate (trade name “Styrofoam” manufactured by Dow Chemical Co., Ltd.) is most preferable because it has high heat insulation and low water absorption.

Polystyrene resin Polystyrene resin foam is obtained by foaming a polystyrene resin, and the polystyrene resin used here is not particularly limited, but is a polystyrene homopolymer or methyl derived from only a styrene monomer. From homopolymers obtained from styrene monomers such as styrene, ethyl styrene, isopropyl styrene, dimethyl styrene, chlorostyrene, homopolymers that are copolymerizable with styrene monomers and styrene, or derivatives thereof Examples thereof include random, block or graft copolymers obtained, modified polystyrene such as brominated polystyrene and rubber-reinforced polystyrene.

  Examples of monomers copolymerizable with styrene include methylstyrene, dimethylstyrene, ethylstyrene, diethylstyrene, isopropylstyrene, bromostyrene, dibromostyrene, tribromostyrene, chlorostyrene, dichlorostyrene, and trichlorostyrene. Vinyl compounds such as vinyltoluene, vinylxylene, divinylbenzene, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butadiene, acrylonitrile and other unsaturated compounds or derivatives thereof, maleic anhydride And itaconic anhydride. These can be used alone or in admixture of two or more. In the present invention, among the styrenic resins described above, polystyrene homopolymers can be particularly preferably used from the viewpoints of economy and moldability.

  The weight average molecular weight of the polystyrene resin is 100,000 to 350,000, preferably 150,000 to 300,000, more preferably 180,000 to 250,000.

Polyethylene resin foam The polyethylene resin foam is obtained by foaming a polyethylene resin, and the polyethylene resin used here is not particularly limited, and includes high density, medium density, low density polyethylene resin, etc. Can be used.

Polypropylene resin foam Polypropylene resin foam is obtained by foaming a polypropylene resin. The polypropylene resin used here is not particularly limited, and is a copolymer of propylene and other olefin resins. Etc. can be used.

Polyurethane resin foam The polyurethane resin foam may be a hard polyurethane foam obtained by reacting a polyisocyanurate component and a polyol component in the presence of a foaming agent.

Phenol-based resin foam A phenol-based resin foam is obtained by foaming a phenol-based resin, and a phenol-based resin foam obtained by mixing a curing agent and a foaming agent with a resol resin can be used.

Examples of the foaming agent foaming agent include physical foaming agents and pyrolytic chemical foaming agents. Although it does not specifically limit as a physical foaming agent, Inorganic gas, such as a carbon dioxide, nitrogen, argon, helium, air, water, methane, ethane, propane, butane (normal butane, isobutane), pentane (normal pentane, isopentane, neopentane) , Cyclopentane), aliphatic hydrocarbons such as hexane, aliphatic alcohols such as methanol, ethanol, and propanol, and ether hydrocarbons such as dimethyl ether. In addition, although a fluorocarbon foaming agent can be used, it is preferable to refrain from using it as much as possible in the sense of the environment because it may destroy the ozone layer and cause global warming.

  Other physical foaming agents are not particularly limited, but examples thereof include alkyl chlorides such as methyl chloride and ethyl chloride, diethyl ether, methyl ethyl ether, isopropyl ether, n-butyl ether, diisopropyl ether, furan, furfural. , Ethers such as 2-methylfuran, tetrahydrofuran, tetrahydropyran, dimethyl ketone, methyl ethyl ketone, diethyl ketone, methyl n-propyl ketone, methyl n-butyl ketone, methyl i-butyl ketone, methyl n-amyl ketone, methyl n-hexyl ketone, Ketones such as ethyl n-propyl ketone and ethyl n-butyl ketone, alcohols such as i-propyl alcohol, butyl alcohol, i-butyl alcohol and t-butyl alcohol, methyl formate Le, ethyl formate ester, formate, propyl ester, butyl formate ester formate, amyl esters, methyl propionate, and the like can be used carboxylic acid esters such as propionic acid ethyl ester. Moreover, an azo compound etc. can be used as a thermal decomposition type chemical foaming agent. These can be used individually or in mixture of 2 or more types. By using these other foaming agents, a good plasticizing effect and a foaming aid effect can be obtained, the extrusion pressure can be reduced, and the foam can be stably produced.

  Among the blowing agents described above, a combination of one or more of hydrocarbons such as propane, normal butane, isobutane, normal pentane, isopentane, cyclopentane and neopentane, alkyl chlorides such as methyl chloride and ethyl chloride, and carbon dioxide preferable. In particular, a combination of butane, ethyl chloride, and carbon dioxide is preferable.

  The amount of the foaming agent added to the resin is 3 to 30 parts by weight, preferably 5 to 15 parts by weight, and more preferably 5 to 10 parts by weight with respect to 100 parts by weight of the styrenic resin.

  The cell diameter of the resin foam is preferably 0.1 mm to 0.8 mm, more preferably 0.15 mm to 0.7 mm, and further preferably 0.2 mm to 0.6 mm.

Halogen Flame Retardant In order to impart flame retardancy, a halogen flame retardant may be added, and the flame retardant usually used for thermoplastic resins can be used without any particular limitation. For example, brominated products of aliphatic or alicyclic hydrocarbons such as hexabromocyclododecane, hexabromobenzene, ethylene bispentabromodiphenyl, decabromodiphenyl ether, octabromodiphenyl ether, 2,3-dibromopropylpentabromophenyl ether, etc. Brominated aromatic compounds, tetrabromobisphenol A, tetrabromobisphenol A bis (2,3-dibromopropyl ether), tetrabromobisphenol A (2-bromoethyl ether), tetrabromobisphenol A diglycidyl ether, tetrabromobisphenol Brominated bisphenols such as A diglycidyl ether and tribromophenol adducts and derivatives thereof, tetrabromobisphenol A polycarbonate oligomer Brominated bisphenol derivatives oligomers such as tetrabromobisphenol A diglycidyl ether and brominated bisphenol adduct epoxy oligomer, ethylene bistetrabromophthalimide, ethylene bisdibromonorbornane dicarboximide, bis (2,4,6-tribromophenoxy) Examples include ethane, brominated SBS block polymers, brominated aromatic compounds such as brominated acrylic resins, chlorinated paraffin, chlorinated naphthalene, perchloropentadecane, chlorinated aromatic compounds, and chlorinated alicyclic compounds. These compounds can be used individually or in mixture of 2 or more types.

  Of the halogen-based flame retardants, bromine-based flame retardants are preferable from the viewpoint of flame retardancy, and hexabromocyclododecane, brominated SBS block polymer, 2,2-bis (4 ′) are particularly preferable from the viewpoint of compatibility with styrene resins. (2 ″, 3 ″ -dibromoalkoxy) -3 ′, 5′-dibromophenyl) -propane is preferred.

  The content of the halogen-based flame retardant in the foam is preferably 0.1 to 10 parts by weight, more preferably 1 to 9 parts by weight, and particularly preferably 2 to 8 parts by weight with respect to 100 parts by weight of the foam. Part. If the amount is less than 0.1 parts by weight, the flame retardancy targeted by the present invention cannot be obtained. If the amount exceeds 10 parts by weight, the moldability during production of the foam may be impaired.

  By allowing a phosphate ester to coexist with a halogen-based flame retardant, combustion can be suppressed even in the case of high flammability containing titanium oxide, achieving high heat insulation, and specified in JIS A9511: 2006R. High flame retardancy can be achieved.

  The phosphate ester used is not limited to triphenyl phosphate, but tricresyl phosphate, trixylylenyl phosphate, cresyl diphenyl phosphate, 2-ethylhexyl diphenyl phosphate, trimethyl phosphate, triethyl phosphate, tributyl As the phosphate, tris (2-ethylhexyl) phosphate, tris (butoxyethyl) phosphate, or condensed phosphate, an aromatic phosphate is preferable, and triphenyl phosphate is particularly preferable.

Regarding the heat ray shielding material kneaded in the heat insulating material, in the present invention, the heat ray shielding material such as a white pigment, black pigment, and colored pigment described below is basically unnecessary, and in some cases, the heat ray shielding material has a heat insulation performance. Although no particular improvement may be obtained or the cost may be high, a heat ray shielding material may be mixed with the heat insulating material if there is no particular problem. It should be noted that heat ray shielding materials such as white pigments, black pigments, and colored pigments described below are also suitably used as materials for a “heat ray shielding material layer” described later.

As the white pigment white pigment, for example, white lead (basic lead _{carbonate: (PbCO 3) 2 · Pb} (OH) 2), zinc white (zinc oxide), titanium oxide, zinc sulfide, lithopone (zinc sulfide and A mixture with barium sulfate), antimony white, mica, aluminum oxide, alumina white, white carbon and the like. Among these, titanium oxide is preferable.

  The average particle diameter of the white pigment (for example, titanium oxide) is not particularly limited, but is preferably 0.1 μm to 0.5 μm (0.15 μm to 0.005 μm) in consideration of the color developability to the resin. 3 μm is more preferable). If the average particle diameter is in this range, the dispersibility and color developability are good, and the whiteness in the visible light region of 400 to 800 nm can be improved. On the other hand, when it is desired to suppress infrared absorption to the resin in the near infrared to far infrared region, 0.8 μm to 1.5 μm is preferable (0.8 μm to 1.0 μm is more preferable). By mixing these white pigments having different average particle diameters in the range of 10 wt% to 90 wt%, it is possible to obtain a mixed titanium oxide with improved reflection in the infrared region and whiteness in the visible light region. .

  The amount of the white pigment added to the heat insulating material is 0.1 to 10 parts by weight, preferably 1 to 8 parts by weight, and more preferably 2 to 4 parts by weight with respect to 100 parts by weight of the styrene resin.

Black pigments Examples of black pigments include graphite, carbon black, chromium black, and copper chromate. Among these, graphite and carbon black are preferable. The graphite may be natural graphite such as flaky graphite, scaly (lumpy) graphite, earthy graphite, artificial graphite, or pyrolytic graphite. Graphite desirably has a fixed carbon number of 80% or more, more preferably 90% or more.

  The average particle size of the black pigment is not particularly limited, but for example, carbon black is preferably 10 to 300 nm (0.01 to 0.3 μm), and 200 to 290 nm (0.2 to 0.29 μm). Is more preferable. Moreover, 1-30 micrometers is preferable in a graphite, and 3-15 micrometers is more preferable. The average particle size of graphite is preferably set to an average particle size of 10 μm or more in order to affect the color developability and the degree of infrared absorption / reflection in the infrared region in the same manner as titanium oxide. On the other hand, if the average particle diameter of graphite exceeds 30 μm, the connectivity of the bubbles in the foam increases and the heat insulation performance is remarkably lowered.

  The amount of the black pigment added to the heat insulating material is 0.1 to 2.5 parts by weight, preferably 0.3 to 2.0 parts by weight, more preferably 0.5 to 100 parts by weight of the styrene resin. -1.2 parts by weight.

The colored pigment is preferably an organic colored pigment having an average particle size of 0.5 μm or less (preferably 0.1 to 0.3 μm). For example, phthalocyanine blue is preferable for a blue pigment. Further, some inorganic colored pigments have an average particle diameter of 1 μm or more, and exhibit an effective reflecting action at locations where the wavelength is large in the infrared region. However, note that inorganic colored pigments, unlike organic pigments, often have poor color developability and dispersibility, and may require a larger amount (for example, 5 times or more) than organic pigments. There is a need to. In general, an increase in the amount of additive added is not preferable because it may act as a nucleating agent when the foam is molded to significantly reduce the bubble diameter, and is not preferable from the viewpoint of cost.

  The amount of the colored pigment added to the styrenic resin is 0.01 to 0.5 parts by weight, preferably 0.03 to 0.2 parts by weight, more preferably 0.05 to 100 parts by weight of the styrenic resin. ~ 0.15 parts by weight.

Other additives In addition, to adjust the size of bubbles as needed, bubble adjusters such as talc and calcium silicate, extrusion aids such as barium stearate and calcium stearate, magnesium oxide, tetrasodium pyrophosphate, etc. It is desirable to add a deoxidizer.

Method for Producing Resin Foam Resin foam can be obtained, for example, by extrusion foaming. The extrusion foaming method used here is, for example, heat-melting a resin, pressing and kneading a foaming agent into the molten resin under high temperature and high pressure, cooling to a temperature suitable for extrusion foaming, and lowering the pressure through a die. It can be the same as the known method of producing by extrusion foaming. Further, secondary foaming may be performed after extrusion foaming, and as this secondary foaming method, a steam / heated air tunnel described in JP-A-63-159034 can be used. It is also possible to use a method for contacting a molding apparatus described in JP-A-63-37916.

For example, the melting temperature when the polystyrene resin is heated and melted is 160 to 240 ° C., preferably 170 to 230 ° C., more preferably 180 to 220 ° C., and the solid raw material is melt-kneaded by an extruder. The pressure at the time of press-fitting the blowing agent, 110~200kg / cm ^2, more preferably 120~185kg / cm ^2. The solid raw material and the foaming agent melted by the extruder are kneaded by a mixer (rotational speed: 20 to 40 rpm, more preferably 25 to 35 rpm) and slowly cooled by a cooler. Moreover, the optimal temperature when cooling and foaming a gel is 100-130 degreeC, More preferably, it is 110-125 degree | times.

  In the case of polyethylene resin foam, polypropylene resin foam, polyurethane resin foam, and phenol resin foam, manufacturing conditions are selected and adjusted using techniques generally known among those skilled in the art. can do.

  In addition, when adding the above-described white pigment (for example, titanium oxide), black pigment (for example, graphite), colored pigment, and phosphate ester, before adding to the heat-melted resin, a master with the resin in advance. It is preferable to make it a batch.

  When producing a master batch of pigment, in order to ensure the stability of the extruder, metal-based stearic acid such as about 5% magnesium stearate may be used. In some cases, the flame retardant performance was lowered or the bubble diameter was changed. On the other hand, the melting point of triphenyl phosphate is around 49 ° C., and if it is directly fed into the extruder during the foam production process, surging of the extruder occurs or the discharge amount is not good at an addition amount of 0.3 parts by weight or more. In some cases, it becomes stable and the productivity is significantly reduced.

  Therefore, as an alternative to stearic acid, triphenyl phosphate of 0.1% to 10%, preferably around 5%, is added in advance in the masterbatch production process of the pigment, so that the mixing ratio of these raw materials is made uniform. As well as good addition of triphenyl phosphate. Also, in the masterbatch manufacturing process, the resin meltability can be further improved by the plasticizing effect of triphenyl phosphate, so that each of the pigment and triphenyl phosphate is fed into the masterbatch rather than directly into the extruder. Thus, it is possible to easily disperse uniformly, and it is possible to obtain a stable dispersibility after extrusion.

Heat ray shielding material layer The material used for the heat ray shielding material layer (heat ray reflecting material, heat ray absorbing material) is not particularly limited as long as it reflects or absorbs heat rays, such as a metal material such as aluminum, polyethylene terephthalate, etc. There are resin etc. In addition, examples include metal oxides such as titanium oxide, zinc oxide, and barium sulfate, ceramics such as mica (mica), paints and adhesives containing pigments, and the like. The details are also described in the “white pigment”, “black pigment” and “organic pigment” sections. Among these, an aluminum foil having a high heat ray reflection effect is preferable as a preferable material.

  Moreover, in order to join a plurality of heat insulating materials and to form a layer of a heat ray shielding material between them, it is also preferable to use an adhesive containing a heat ray shielding material at the time of joining. The adhesive is not particularly limited as long as it can join the heat insulating layers or the heat insulating material layer and the heat ray shielding material layer. However, the adhesive is not limited to epoxy adhesive, urethane adhesive, and synthetic rubber hot. Examples thereof include a melt adhesive.

  When a flat polystyrene foam is used as the heat insulating material layer and an aluminum foil is used as the heat ray shielding material layer, a film made of polystyrene is lined by dry lamination on at least both surfaces of the aluminum foil. An aluminum foil with a film may be used, and the aluminum foil with a film may be bonded to a flat polystyrene foam by thermal lamination. Further, an adhesive may be applied to the heat insulating material, and the aluminum foil may be joined, and the bonding method at this time may be either full-surface bonding or partial bonding (dotting or linear bonding).

  The heat ray shielding material layer may be arranged on one surface between the heat insulating material layers, for example, a strip-like heat ray shielding material, and arranged in a stripe shape between the heat insulating material layers. May be.

Characteristics of the composite heat insulating material The heat conductivity of the composite heat insulating material according to the present invention is 96.5% or less compared to the heat conductivity of the heat insulating material to be compared (heat insulating material having no heat ray shielding material layer). A reduction ratio is preferable, a reduction ratio of 92.0% or less is more preferable, and a reduction ratio of 87.0% or less is more preferable. In addition, thermal conductivity is measured by the method based on JIS A 1412-2: 1999.

  As shown in the following Examples and Comparative Examples, various composite heat insulating materials were produced and their thermal conductivity was measured. Moreover, the density and bubble diameter (cell size) were measured about the foam board used as the base of a composite heat insulating material. A method for measuring the following physical property values will be described.

(density)
The density of the foam plate was calculated by dividing the weight (kg) of the foam by the volume (m ³ ) of the foam.
(Bubble diameter)
The bubble diameter of the foam plate was measured by a method based on ASTM D 3567.
(Thermal conductivity)
The thermal conductivity of the foamed plate was measured by a method based on JIS A 1412-2: 1999.

<The manufacturing method of the foam board (1) used in Examples 1-7 and Comparative Examples 1-2>
0.1 parts by weight of barium stearate (manufactured by NOF Corporation) as a lubricant for an extruder and magnesium oxide (Kamishima Chemical L-10) as a stabilizer for 100 parts by weight of a styrene resin having a weight average molecular weight of 210,000. 05 parts by weight, 0.5 part by weight of polyethylene (Daurex) as a foam control agent, and 2 parts by weight of hexabromocyclododecane (HBCD, Albemarle SAYTEX HP-900) as a flame retardant are put into a hopper of an extruder, and a foaming agent 2 parts by weight of industrial butane (normal butane / isobutane = 65/35), 4 parts by weight of ethyl chloride and 3 parts by weight of carbon dioxide were press-fitted (180 kg / cm ² ) and kneaded at 200 ° C. Next, the gel is uniformly cooled with a cooler, adjusted to an optimal foaming temperature (120 ° C.), and extruded and foamed from the die under atmospheric pressure to obtain a bubble diameter of about 0.58 mm, a density of about 27 Kg / cm ³ , A foamed plate having a thickness of about 30 mm was produced (measured values in a state where the skin layer was trimmed). In order to produce a test piece, immediately after extrusion foaming, 5 sheets were sliced in the thickness direction to obtain 5 foam plates of 5 mm (thickness) × 200 mm × 200 mm per sheet. The foamed plate (1) thus obtained was used in the following examples and comparative examples.

<Comparative Example 1>
Five foam plates (1) were laminated (a total of five foam plates from the first layer foam plate to the fifth layer foam plate) to produce a heat insulating material according to Comparative Example 1. In addition, the foamed plates were not bonded to each other and overlapped in a free state (the same applies to Examples 1 to 7 and Comparative Example 2 below). About the thermal conductivity measurement of the heat insulating material obtained in this way, a heating plate was installed on the outside of the first-layer foam plate using AUTO-Λ HC-072 manufactured by Eihiro Seiki Co., Ltd. and about 39.8. The heat conductivity was measured at an average temperature of 23 ° C. by measuring a temperature of about 7.9 ° C. by installing a heat flow meter and a cooling plate outside the fifth layer foam plate (Example 1 below). -7 and the same in Comparative Example 2). As a result, the thermal conductivity was 37.7 mW / mK (see Table 1).

<Comparative Example 2>
Five foam plates (1) are laminated, and an aluminum foil (Sun Aluminum Industry Co., Ltd.) having a thickness of 11 μm is further laminated on the first foam plate to produce a composite heat insulating material according to Comparative Example 2. did. The result of measuring the thermal conductivity of this composite heat insulating material was 37.7 mW / mK, which was the same as the result of Comparative Example 1 (see Table 1).

<Example 1>
When laminating five foam plates (1), an aluminum foil having a thickness of 11 μm is sandwiched between the first and second foam plates, and the composite heat insulating material according to Example 1 Was made. The result of measuring the thermal conductivity of this composite heat insulating material was 36.2 mW / mK. This result was reduced to 96.0% as compared with the thermal conductivity of 37.7 mW / mK of the heat insulating material according to Comparative Example 1 (see Table 1).

<Example 2>
When laminating five foam plates (1), an aluminum foil having a thickness of 11 μm is sandwiched between the second and third foam plates, and the composite heat insulating material according to the second embodiment. Was made. The result of measuring the thermal conductivity of this composite heat insulating material was 35.9 mW / mK. This result was reduced to 95.2% compared to the thermal conductivity of 37.7 mW / mK of the heat insulating material according to Comparative Example 1 (see Table 1).

<Example 3>
When laminating five foam plates (1), an aluminum foil having a thickness of 11 μm is sandwiched between the third and fourth foam plates, and the composite heat insulating material according to Example 3 Was made. The result of measuring the thermal conductivity of this composite heat insulating material was 35.9 mW / mK. This result was reduced to 95.2% compared to the thermal conductivity of 37.7 mW / mK of the heat insulating material according to Comparative Example 1 (see Table 1).

<Example 4>
When laminating five foam plates (1), an aluminum foil having a thickness of 11 μm is sandwiched between the fourth foam plate and the fifth foam plate, and the composite heat insulating material according to Example 4 Was made. The result of measuring the thermal conductivity of this composite heat insulating material was 36.3 mW / mK. This result was reduced to 96.3% compared to the thermal conductivity of 37.7 mW / mK of the heat insulating material according to Comparative Example 1 (see Table 1).

<Example 5>
When laminating the five foam plates (1), between the first layer foam plate and the second layer foam plate and between the fourth layer foam plate and the fifth layer foam plate An aluminum foil having a thickness of 11 μm was sandwiched therebetween to produce a composite heat insulating material according to Example 5. The result of measuring the thermal conductivity of this composite heat insulating material was 34.6 mW / mK. This result was reduced to 91.8% compared to the thermal conductivity of 37.7 mW / mK of the heat insulating material according to Comparative Example 1 (see Table 1).

<Example 6>
When laminating the five foam plates (1), between the second-layer foam plate and the third-layer foam plate and between the third-layer foam plate and the fourth-layer foam plate An aluminum foil having a thickness of 11 μm was sandwiched therebetween to produce a composite heat insulating material according to Example 6. The result of measuring the thermal conductivity of this composite heat insulating material was 34.7 mW / mK. This result was reduced to 92.0% compared to the thermal conductivity of 37.7 mW / mK of the heat insulating material according to Comparative Example 1 (see Table 1).

<Example 7>
When the five foamed plates (1) were laminated, an aluminum foil having a thickness of 11 μm (a total of four) was sandwiched between the foamed plates to produce a composite heat insulating material according to Example 7. The result of measuring the thermal conductivity of this composite heat insulating material was 32.8 mW / mK. This result was reduced to 87.0% compared to the thermal conductivity of 37.7 mW / mK of the heat insulating material according to Comparative Example 1 (see Table 1).

  From the results of Examples 1 to 7 and Comparative Examples 1 and 2 described above, it was not possible to reduce the thermal conductivity even when a heat ray shielding layer such as an aluminum foil was disposed on the surface of the heat insulating material (Comparative Example 2). ), It was found that the heat conductivity can be reduced by disposing a heat ray shielding layer in the heat insulating material (between each foamed plate) (Examples 1 to 7). Moreover, it turned out that heat conductivity can be reduced more, so that the number of the heat ray shielding layers arrange | positioned in a heat insulating material is increased (Examples 5-7).

<The manufacturing method of the foam board (2) used in Example 8 and Comparative Example 3>
0.1 parts by weight of barium stearate (manufactured by NOF Corporation) as a lubricant for an extruder and magnesium oxide (Kamishima Chemical L-10) as a stabilizer for 100 parts by weight of a styrene resin having a weight average molecular weight of 210,000. 08 parts by weight, 0.05 parts by weight of talc (Fuji talc, talc LMR) as a foam regulator, and 4.5 parts by weight of hexabromocyclododecane (HBCD, Albemarle SAYTEX HP-900) as a flame retardant are used in the hopper of the extruder. As a blowing agent, 3.0 parts by weight of industrial butane (isobutane), 2.4 parts by weight of ethyl chloride, and 2.5 parts by weight of carbon dioxide were injected (180 kg / cm ² ) and kneaded at 200 ° C. Next, the gel is uniformly cooled with a cooler, adjusted to an optimal foaming temperature (120 ° C.), and extruded and foamed from a die under atmospheric pressure to obtain a bubble diameter of about 0.23 mm, a density of about 32 Kg / cm ³ , A foamed plate having a thickness of about 30 mm was produced (measured values in a state where the skin layer was trimmed). In order to produce a test piece, immediately after extrusion foaming, 5 sheets were sliced in the thickness direction to obtain 5 foam plates of 5 mm (thickness) × 200 mm × 200 mm per sheet. The foamed plate (2) thus obtained was used in the following examples and comparative examples.

<Comparative Example 3>
Five foam plates (2) were laminated (a total of five sheets from the first layer foam plate to the fifth layer foam plate) to produce a heat insulating material according to Comparative Example 3. Note that the foam plates were not bonded to each other and overlapped in a free state (the same applies to Example 8 below). About the thermal conductivity measurement of the heat insulating material obtained in this way, a heating plate was installed on the outside of the first-layer foam plate using AUTO-Λ HC-072 manufactured by Eihiro Seiki Co., Ltd. and about 39.8. The heat conductivity was measured at an average temperature of 23 ° C. by measuring a temperature of about 7.9 ° C. by setting a heat flow meter and a cooling plate outside the fifth layer foam plate (Example 8 below). The same applies to As a result, the thermal conductivity was 29.9 mW / mK (see Table 2).
Since the foamed plate (2) having a small bubble diameter of about 0.23 mm was used compared to the foamed plate (1) having a bubble diameter of about 0.58 mm, the thermal conductivity was 37. Compared to 7 mW / mK, it is greatly reduced. This is because the bubble film thickness is reduced due to the reduction of the bubble diameter, but the total bubble film per thickness is increased and radiation is reduced.

<Example 8>
When the five foamed plates (2) were laminated, an aluminum foil having a thickness of 11 μm (a total of four) was sandwiched between the foamed plates to produce a composite heat insulating material according to Example 8. The result of measuring the thermal conductivity of this composite heat insulating material was 27.1 mW / mK. This result was reduced to 90.6% compared to the thermal conductivity of 29.9 mW / mK of the heat insulating material according to Comparative Example 3 (see Table 2).
From the results of Example 8, by providing a heat ray shielding layer such as an aluminum foil in the heat insulating material (between each foamed plate) even if the foam diameter is relatively small like the foamed plate (2), It can be seen that the thermal conductivity of the heat insulating material can be further reduced.

<The manufacturing method of the foam board (3) used in Example 9 and Comparative Example 4>
0.1 parts by weight of barium stearate (manufactured by NOF Corporation) as a lubricant for an extruder and magnesium oxide (Kamishima Chemical L-10) as a stabilizer for 100 parts by weight of a styrene resin having a weight average molecular weight of 210,000. 08 parts by weight, 0.2 parts by weight of talc (Fuji talc, talc LMR) as a bubble regulator, and 6.0 parts by weight of hexabromocyclododecane (HBCD, Albemarle SAYTEX HP-900) as a flame retardant, oxidized as a heat ray shielding material 4.0 parts by weight of titanium (TiO2, DuPont R-104) (titanium oxide uses a master batch of titanium oxide / polystyrene = 30% / 70%) is introduced into the hopper of an extruder, and industrial butane (isobutane as a blowing agent) ) 3.5 parts by weight, ethyl chloride 2.0 parts by weight, carbon dioxide 2.0 parts by weight (160 kg / cm) ² ) and kneaded at 200 ° C. Next, the gel is uniformly cooled with a cooler, adjusted to an optimum foaming temperature (120 ° C.), and extruded and foamed from the die under atmospheric pressure to obtain a bubble diameter of about 0.32 mm, a density of about 32 kg / cm ³ , A foamed plate having a thickness of about 75 mm was produced (both measured values with the skin layer trimmed). In order to produce a test piece, immediately after extrusion foaming, 5 sheets were sliced in the thickness direction to obtain 5 foam plates of 5 mm (thickness) × 200 mm × 200 mm per sheet. The foamed plate (3) thus obtained was used in the following examples and comparative examples.

<Comparative example 4>
Five foam plates (3) were laminated (a total of five sheets from the first layer foam plate to the fifth layer foam plate) to produce a heat insulating material according to Comparative Example 4. The foamed plates were not bonded to each other and overlapped in a free state (the same applies to Example 9 below). About the thermal conductivity measurement of the heat insulating material obtained in this way, a heating plate was installed on the outside of the first-layer foam plate using AUTO-Λ HC-072 manufactured by Eihiro Seiki Co., Ltd. and about 39.8. The heat conductivity was measured at an average temperature of 23 ° C. by measuring the temperature at about 7.9 ° C. by installing a heat flow meter and a cooling plate outside the fifth layer foam plate (Example 9 below). The same applies to As a result, the thermal conductivity was 31.8 mW / mK (see Table 2).

<Example 9>
When the five foamed plates (3) were laminated, an aluminum foil having a thickness of 11 μm (a total of four) was sandwiched between the foamed plates to produce a composite heat insulating material according to Example 9. The result of measuring the thermal conductivity of this composite heat insulating material was 30.5 mW / mK. This result was reduced to 95.9% compared to the thermal conductivity of 31.8 mW / mK of the heat insulating material according to Comparative Example 4 (see Table 2).
From the result of Example 9, even if it is a foam board kneaded with titanium oxide which is a heat ray shielding material like the foam board (3), a heat ray shielding layer such as an aluminum foil is provided in the heat insulating material (between each foam board). By providing, it turns out that the thermal conductivity of a heat insulating material can further be reduced.

<The manufacturing method of the foam board (4) used in Example 10 and Comparative Example 5>
0.1 parts by weight of barium stearate (manufactured by NOF Corporation) as a lubricant for an extruder and magnesium oxide (Kamishima Chemical L-10) as a stabilizer for 100 parts by weight of a styrene resin having a weight average molecular weight of 210,000. 08 parts by weight, polyethylene (Daulex) 1.0 part by weight as a foam regulator, 3.0 parts by weight of hexabromocyclododecane (HBCD, Albemarle SAYTEX HP-900) as a flame retardant, carbon black (CB Engineered Carbons Arosperse 15) 7.0 parts by weight (carbon black uses carbon black / polystyrene = 30% / 70% masterbatch) was introduced into the hopper of the extruder, and industrial butane (isobutane as a blowing agent). ) 2.5 parts by weight, cyclopentane 1.4 layers An amount of 2.5 parts by weight of carbon dioxide was press-fitted (160 kg / cm ² ) and kneaded at 200 ° C. Next, the gel is uniformly cooled with a cooler, adjusted to an optimum foaming temperature (120 ° C.), and extruded and foamed from the die under atmospheric pressure, whereby a bubble diameter of about 0.21 mm, a density of about 36 Kg / cm ³ , A foam plate having a thickness of about 50 mm was produced (measured values in a state where the skin layer was trimmed). In order to produce a test piece, immediately after extrusion foaming, 5 sheets were sliced in the thickness direction to obtain 5 foam plates of 5 mm (thickness) × 200 mm × 200 mm per sheet. The foamed plate (4) thus obtained was used in the following examples and comparative examples.

<Comparative Example 5>
Five foam plates (4) were laminated (a total of five foam plates from the first layer foam plate to the fifth layer foam plate) to produce a heat insulating material according to Comparative Example 5. In addition, the foamed plates were not bonded to each other and overlapped in a free state (the same applies to Example 10 below). About the thermal conductivity measurement of the heat insulating material obtained in this way, a heating plate was installed on the outside of the first-layer foam plate using AUTO-Λ HC-072 manufactured by Eihiro Seiki Co., Ltd. and about 39.8. The heat conductivity was measured at an average temperature of 23 ° C. by measuring a temperature of about 7.9 ° C. by installing a heat flow meter and a cooling plate outside the fifth layer foam plate (Example 10 below). The same applies to As a result, the thermal conductivity was 29.6 mW / mK (see Table 2).

<Example 10>
When the five foamed plates (4) were laminated, an aluminum foil having a thickness of 11 μm (a total of four) was sandwiched between the foamed plates to produce a composite heat insulating material according to Example 10. The result of measuring the thermal conductivity of this composite heat insulating material was 29.4 mW / mK. This result was reduced to 99.3% compared to the thermal conductivity of 29.6 mW / mK of the heat insulating material according to Comparative Example 5 (see Table 2).
A foamed plate kneaded with carbon black excellent as a heat ray shielding material, such as the foamed plate (4), already has a sufficiently reduced thermal conductivity. From the results of Example 10, it can be seen that the heat conductivity of the heat insulating material can be further reduced even when a heat ray shielding layer such as an aluminum foil is provided in such a heat insulating material (between each foamed plate).

<The manufacturing method of the foam board (5) used in Example 11 and Comparative Example 6>
0.1 parts by weight of barium stearate (manufactured by NOF Corporation) as a lubricant for an extruder and magnesium oxide (Kamishima Chemical L-10) as a stabilizer for 100 parts by weight of a styrene resin having a weight average molecular weight of 210,000. 08 parts by weight, 0.5 parts by weight of polyethylene (Daulex) as a bubble regulator, 4.2 parts by weight of hexabromocyclododecane (HBCD, Albemarle SAYTEX HP-900) as a flame retardant, graphite (GP, Texcal Japan TX-GA 98/10) 2.5 parts by weight (graphite is graphite / polystyrene = 30% / 70% master batch) was charged into the hopper of the extruder, and industrial butane (isobutane as a blowing agent). ) 4.1 parts by weight, carbon dioxide 1.0 part by weight, water 1.0 part by weight (18 It was kneaded in kg / cm ²⁾ to 200 ° C.. Next, the gel is uniformly cooled with a cooler, adjusted to an optimum foaming temperature (120 ° C.), and extruded and foamed from the die under atmospheric pressure to obtain a bubble diameter of about 0.12 mm, a density of about 36 Kg / cm ³ , A foamed plate having a thickness of about 30 mm was produced (measured values in a state where the skin layer was trimmed). In order to produce a test piece, immediately after extrusion foaming, 5 sheets were sliced in the thickness direction to obtain 5 foam plates of 5 mm (thickness) × 200 mm × 200 mm per sheet. The foamed plate (5) thus obtained was used in the following examples and comparative examples.

<Comparative Example 6>
Five foam plates (5) were laminated (a total of five foam plates from the first layer foam plate to the fifth layer foam plate) to produce a heat insulating material according to Comparative Example 6. Note that the foam plates were not bonded to each other and overlapped in a free state (the same applies to Example 11 below). About the thermal conductivity measurement of the heat insulating material obtained in this way, a heating plate was installed on the outside of the first-layer foam plate using AUTO-Λ HC-072 manufactured by Eihiro Seiki Co., Ltd. and about 39.8. The heat conductivity was measured at an average temperature of 23 ° C. by measuring a temperature of about 7.9 ° C. by installing a heat flow meter and a cooling plate outside the fifth layer foam plate (Example 11 below). The same applies to As a result, the thermal conductivity was 27.5 mW / mK (see Table 2).

<Example 11>
When the five foamed plates (5) were laminated, an aluminum foil having a thickness of 11 μm (a total of four) was sandwiched between the foamed plates to produce a composite heat insulating material according to Example 11. The result of measuring the thermal conductivity of this composite heat insulating material was 27.4 mW / mK. This result was reduced to 99.6% as compared with the thermal conductivity 27.5 mW / mK of the heat insulating material according to Comparative Example 6 (see Table 2).
A foamed plate kneaded with graphite excellent as a heat ray shielding material, such as the foamed plate (5), has already sufficiently reduced thermal conductivity. From the results of Example 11, it can be seen that even when a heat ray shielding layer such as an aluminum foil is provided in such a heat insulating material (between each foamed plate), the heat conductivity of the heat insulating material can be further reduced.

<Comparative Example 7>
A hole with a diameter of about 1 mm and a depth of about 2 mm is drilled on the surface of the five foam plates (1) at about 1 cm square (ie, hole density: 1 / cm ² ). A heat insulating material according to Comparative Example 7 was manufactured by laminating (a total of five sheets from the first layer foam plate to the fifth layer foam plate). In addition, the first and fifth layer foam plates have holes on one side only, and the second to fourth layer foam plates are on both sides so that there are no holes on both surfaces of the heat insulating material. Holes were made, and the foamed plates were not bonded to each other and overlapped in a free state (the same applies to Example 12 below). About the thermal conductivity measurement of the heat insulating material obtained in this way, a heating plate was installed on the outside of the first-layer foam plate using AUTO-Λ HC-072 manufactured by Eihiro Seiki Co., Ltd. and about 39.8. The heat conductivity was measured at an average temperature of 23 ° C. by measuring a temperature of about 7.9 ° C. by installing a heat flow meter and a cooling plate outside the fifth layer foam plate (Example 12 below). The same applies to As a result, the thermal conductivity was 37.7 mW / mK, which was the same as Comparative Example 1 in which no holes were formed (see Table 3).

<Example 12>
When five perforated foam plates used in Comparative Example 7 were laminated, an aluminum foil having a thickness of 11 μm (a total of 4 sheets) was sandwiched between the foam plates to produce a composite heat insulating material according to Example 12. The result of measuring the thermal conductivity of this composite heat insulating material was 32.4 mW / mK. This result was reduced to 85.9% in comparison with the thermal conductivity of 37.7 mW / mK of the heat insulating material according to Comparative Example 7, and was almost the same as Example 7 in which no holes were formed. (See Table 3).

<Comparative Example 8>
Holes with a diameter of about 3 mm and a depth of about 2 mm are drilled on the surface of five foamed plates (1) at about 1 cm square (ie, hole density: 1 piece / cm ² ). Were laminated (a total of five sheets from the first layer foam plate to the fifth layer foam plate) to produce a heat insulating material according to Comparative Example 8. In addition, the first and fifth layer foam plates have holes on one side only, and the second to fourth layer foam plates are on both sides so that there are no holes on both surfaces of the heat insulating material. Holes were made, and the foamed plates were not bonded to each other and overlapped in a free state (the same applies to Example 13 below). About the thermal conductivity measurement of the heat insulating material obtained in this way, a heating plate was installed on the outside of the first-layer foam plate using AUTO-Λ HC-072 manufactured by Eihiro Seiki Co., Ltd. and about 39.8. The heat conductivity was measured at an average temperature of 23 ° C. by measuring a temperature of about 7.9 ° C. by setting a heat flow meter and a cooling plate outside the fifth layer foam plate (Example 13 below). The same applies to As a result, the thermal conductivity was 37.8 mW / mK, which was almost the same as that of Comparative Example 1 in which no holes were formed (see Table 3).

<Example 13>
When five perforated foam plates used in Comparative Example 8 were laminated, an aluminum foil having a thickness of 11 μm (total of 4 sheets) was sandwiched between the foam plates to produce a composite heat insulating material according to Example 13. The result of measuring the thermal conductivity of this composite heat insulating material was 32.6 mW / mK. This result was reduced to 86.5% in comparison with the thermal conductivity of 37.8 mW / mK of the heat insulating material according to Comparative Example 8, and was almost the same as Example 7 in which no holes were formed. (See Table 3).

<Comparative Example 9>
A hole having a diameter of about 1 mm and a depth of about 2 mm is drilled on the surface of the five foamed plates (4) in a square of about 1 cm (ie, hole density: 1 / cm ² ). A heat insulating material according to Comparative Example 9 was manufactured by laminating (a total of five sheets from the first layer foam plate to the fifth layer foam plate). In addition, the first and fifth layer foam plates have holes on one side only, and the second to fourth layer foam plates are on both sides so that there are no holes on both surfaces of the heat insulating material. Holes were made, and the foamed plates were not bonded to each other and overlapped in a free state (the same applies to Example 14 below). About the thermal conductivity measurement of the heat insulating material obtained in this way, a heating plate was installed on the outside of the first-layer foam plate using AUTO-Λ HC-072 manufactured by Eihiro Seiki Co., Ltd. and about 39.8. The heat conductivity was measured at an average temperature of 23 ° C. by measuring a temperature of about 7.9 ° C. by installing a heat flow meter and a cooling plate outside the fifth layer foam plate (Example 14 below). The same applies to As a result, the thermal conductivity was 29.5 mW / mK, which was almost the same as that of Comparative Example 5 in which no holes were formed (see Table 3).

<Example 14>
When five perforated foam plates used in Comparative Example 9 were laminated, an aluminum foil having a thickness of 11 μm (a total of four sheets) was sandwiched between the foam plates to produce a composite heat insulating material according to Example 14. The result of measuring the thermal conductivity of this composite heat insulating material was 29.4 mW / mK. This result was reduced to 99.7% compared to the thermal conductivity of 29.5 mW / mK of the heat insulating material according to Comparative Example 9, and was almost the same as Example 10 in which no holes were formed. (See Table 3).

<Comparative Example 10>
A hole having a diameter of about 1 mm and a depth of about 2 mm is drilled on the surface of the five foamed plates (5) in a square of about 1 cm (ie, hole density: 1 / cm ² ). A heat insulating material according to Comparative Example 10 was manufactured by laminating (a total of five sheets from the first layer foam plate to the fifth layer foam plate). In addition, the first and fifth layer foam plates have holes on one side only, and the second to fourth layer foam plates are on both sides so that there are no holes on both surfaces of the heat insulating material. Holes were made, and the foamed plates were not bonded to each other and overlapped in a free state (the same applies to Example 15 below). About the thermal conductivity measurement of the heat insulating material obtained in this way, a heating plate was installed on the outside of the first-layer foam plate using AUTO-Λ HC-072 manufactured by Eihiro Seiki Co., Ltd. and about 39.8. The heat conductivity was measured at an average temperature of 23 ° C. by measuring a temperature of about 7.9 ° C. by installing a heat flow meter and a cooling plate outside the fifth layer foam plate (Example 15 below). The same applies to As a result, the thermal conductivity was 27.5 mW / mK, which was the same as that of Comparative Example 6 in which holes were not formed (see Table 3).

<Example 15>
When five perforated foam plates used in Comparative Example 10 were laminated, an aluminum foil having a thickness of 11 μm (a total of four sheets) was sandwiched between the respective foam plates to produce a composite heat insulating material according to Example 15. The result of measuring the thermal conductivity of this composite heat insulating material was 27.4 mW / mK. This result was reduced to 99.6% as compared with the thermal conductivity of 27.5 mW / mK of the heat insulating material according to Comparative Example 10, and was the same as Example 11 in which no holes were formed. (See Table 3).

  From the results of Examples 12 to 15, even if a defect such as opening or scratching occurs in the manufacturing process or processing process of the foam plate, the effect of the present invention is not affected. I understood that.

Claims (6)

  A composite heat insulating material comprising a plurality of heat insulating material layers and a heat ray shielding material layer disposed between the heat insulating material layers.   The composite heat insulating material according to claim 1, wherein a layer of a heat ray shielding material is not disposed on a surface layer of the composite heat insulating material.   The composite heat insulating material according to claim 1 or 2, wherein the heat insulating material is made of a resin foam.   The composite heat insulating material according to any one of claims 1 to 3, wherein the resin foam does not contain a heat ray shielding material.   The composite heat insulating material according to any one of claims 1 to 4, wherein a bubble diameter of the resin foam is 0.1 mm to 0.8 mm.   The composite heat insulating material according to any one of claims 1 to 5, wherein the layers of the heat ray shielding material are arranged at intervals of 1 mm or more.