JP2010059756A - High performance heat insulation material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high performance heat insulation material which has reduced performance change, excellent heat insulation performance and excellent environmental performance, by the use of a closed cell resin foam as a core material to make the heat insulation material into a vacuum heat insulation material without depending only on the degree of vacuum. <P>SOLUTION: Characteristically, the high performance heat insulation material is composed of the closed cell resin foam (A) and a gas barrier film (B), and the entire resin foam (A) as a core material is covered with the gas barrier film (B), and the space between the resin foam (A) and the gas barrier film (B) is ≥10<SP>-9</SP>Pa and <1.01325×10<SP>5</SP>Pa. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a high-performance heat insulating material having a small performance change, high heat insulating property, and high environmental performance.

In the past, foamed urethane obtained by foaming urethane resin with Freon gas has been widely used as a highly heat-insulating heat insulating material for houses.
However, in the growing environmental consciousness, ozone layer destruction by chlorofluorocarbon gas is regarded as a problem, and a heat insulating material for removing chlorofluorocarbon has been strongly demanded. Development of materials (Patent Document 2) has been started.
Among them, the vacuum heat insulating material is a heat insulating material having high heat insulating performance as compared with the foamed resin heat insulating material, and its use as a building material is also being promoted.
However, the vacuum heat insulating material has a problem that the heat insulating performance is remarkably deteriorated over time due to a pinhole of a gas film which is a skin material.

One of the causes of significant performance degradation is that many of the vacuum heat insulating materials use fiber-based heat insulating materials such as glass fiber as a core material (Patent Document 3). That is, because the vacuum breaks, the heat insulation performance is comparable to that of the fiber heat insulation material having a heat insulation performance lower than that of the resin foam heat insulation material.
Although the examination of a gas barrier film is widely performed with respect to the subject of this performance fall, sufficient result is not obtained.
JP 2007-332203 A JP 2007-239288 A JP 2006-220214 A

  The problem to be solved by the present invention is that, in view of the above-mentioned problems, by using a closed cell resin foam as a core material, a vacuum heat insulating material that does not depend only on the degree of vacuum makes a small performance change and high heat insulation. The purpose is to provide a high-performance heat insulating material having high performance and high environmental performance.

As a result of intensive studies to achieve the above object, the following has been solved.
1) A heat insulating material of a structure comprising a closed cell resin foam (A) and a gas barrier film (B), the resin foam (A) as a core material and the whole covered with a gas barrier film (B), The heat insulating material (V) whose decompression degree inside a structure is 10 < ^-9 > Pa or more and less than 1.01325 * 10 < ⁵ > Pa.
2) The resin foam (A) has pores (L) having an average pore diameter of 1 μm or more and 1000 μm or less, and pores (S) having an average pore diameter of 0.01 μm or more and less than 1 μm, and a porosity (X) of 80 % Of the heat insulating material (V) according to 1) above.
3) The resin foam (A number density of voids (L)) of 10 ² / mm ² or more 10 ⁷ / mm ² or less, the number density of vacancies (S) is 10 ² / [mu] m ² or more The heat insulating material (V) according to 2) above, which is 10 ⁷ pieces / μm ² or less.

  ADVANTAGE OF THE INVENTION According to this invention, the high performance heat insulating material which has few performance changes, high heat insulation, and high environmental performance can be provided, and it is used suitably for the heat insulating material for houses, etc.

First, the closed cell resin foam (A) will be described.
The closed cell resin foam (A) in the present invention refers to a resin foam having a closed cell rate of 50% or more and less than 100% measured by a method described later. When the closed cell ratio is less than 50%, the heat insulating performance of the core material is lowered, and the performance change is increased. A closed cell ratio of 100% or more cannot exist on the measurement principle.
A preferable closed cell ratio in the case where higher heat insulating performance is required is 70% or more and less than 100%, and more preferably 80% or more and less than 100%.

  Furthermore, in order to improve the heat insulation performance of the resin foam (A), the porosity (X) measured by the method described later is preferably 60% or more and less than 100%. If the porosity (X) is 60% or less, sufficient heat insulation performance may not be exhibited. Further, a foam having a porosity (X) of 100% or more cannot exist on the measurement principle. The preferable porosity (X) when higher heat insulation performance is required is 80% or more and less than 100%.

Further, the preferred range of the closed cell ratio and the void ratio is such that the closed cell ratio is 50% or more and less than 100% and the void ratio (X) is 60% or more and less than 100%, more preferably the closed cell ratio is 80% or more and 100%. % And the porosity (X) is 80% or more and less than 100%.
The method for producing the resin foam (A) as described above can be produced by controlling the resin viscosity and the degree of crosslinking, and can be produced by a known method depending on the resin used.

  Examples of resins used include polyurethane resins, polystyrene resins, polypropylene resins, aromatic polyester resins, aliphatic polyester resins, polyethylene resins, methacrylic resins, polycarbonate resins, and phenol resins. These may be used alone or in combination of two or more.

  As a manufacturing method, a foaming agent such as butane or pentane is added while mixing resin raw materials, and a foaming method in which polymerization and foaming are simultaneously performed by heating, or a foaming agent such as carbon dioxide gas while the resin is heated and melted with an extruder. A method called extrusion foaming in which foaming is performed by press-fitting and extruding into the atmosphere is not limited thereto.

  Moreover, when the further high heat insulation performance is calculated | required by the resin foam (A), the average pore diameter seen when the cross section of a foam is observed with a microscope etc. is 1 micrometer or more and 1000 micrometers or less pores (L), and an average pore diameter is It is preferable that the resin foam (A) has pores (S) of 0.01 μm or more and less than 1 μm and a porosity (X) of 80% or more.

  When the average hole diameter of the holes (L) exceeds 1000 μm, heat transfer due to convection and radiation of the gas present in the holes becomes large, and high heat insulation performance may not be obtained. In order to effectively suppress the heat transfer of the gas in the pores, the average pore diameter of the pores (L) is preferably 1 μm or more and 500 μm or less. More preferably, they are 1 micrometer or more and 100 micrometers or less.

On the other hand, if the porosity (X) is less than 80%, heat transfer by the resin in the foam is increased, so that the heat insulation is likely to be lowered. From the viewpoint of effectively suppressing the heat transfer of the resin in the foam, the porosity (X) is preferably 90% or more, more preferably 93% or more.
Further, since the smaller the hole (S), the thinner the hole wall surface, the average hole diameter of the hole (S) is preferably less than 1 μm. The pores (S) are preferably 0.05 μm or more and less than 1 μm, and more preferably 0.10 μm or more and less than 1 μm.

The number density of holes (L) is 10 ² / mm ² or more and 10 ⁷ / mm ² or less, and the number density of holes (S) is 10 ² / μm ² or more and 10 ⁷ / μm ² or less. Is preferred. By doing so, it is possible to form minute holes (S) around the holes (L), and it is possible to significantly reduce the higher porosity and the heat transfer of the resin. More preferably, the number density of the holes (L) is 10 ³ pieces / mm ² or more and 10 ⁷ pieces / mm ² or less, and the number density of the hole diameter (S) is 10 ³ pieces or more / μm ² 10 ⁷ pieces / μm ² or less. It is.

  Moreover, when it is going to obtain the resin foam of high porosity (X), it is preferable that the area occupation rate of a void | hole (S) is larger than 0%. The area occupation ratio of the pores (S) is more preferably 10% or more, further preferably 20% or more, and particularly preferably 30% or more. The larger the area occupancy of the holes (S), the more effective, but the practical upper limit is about 50%.

  Moreover, it is preferable that the void | hole containing a void | hole (L) and a void | hole (S) is scattered uniformly in the resin foam (A).

  As a method for producing the resin foam (A) as described above, a foaming agent is obtained by mixing a resin C and a resin D that are different from each other in a range where the difference in solubility in the foaming agent exceeds 0% and less than 10%. After impregnating and foaming a mixture of different resin E and resin F having different solubility in the foaming agent of 10% or more in a nano-alloyed form, the resin F is decomposed. The method etc. can be mentioned.

  First, the former method of impregnating a foaming agent with a foaming agent in a mixture of different resins C and D within a range where the difference in solubility in the foaming agent exceeds 0% and less than 10% will be described.

  This method is a method of generating vacancies (L) and vacancies (S) by a slight solubility difference between island components and sea components uniformly dispersed in the nano order.

  Resin C and resin D used for foaming are not particularly limited, and examples thereof include polyurethane resin, polystyrene resin, polypropylene resin, polyester resin, polylactic acid resin, polyethylene resin, methacrylic resin, and polycarbonate resin. It is done. In particular, when importance is placed on environmental performance, the resin C is preferably a polylactic acid-based resin, and the resin D is preferably the other resin described above.

  The polylactic acid-based resin here refers to a polylactic acid resin obtained by ring-opening polymerization of lactide or direct polymerization of lactic acid, and a polylactic acid-based copolymer obtained by ring-opening polymerization of lactide. In particular, a mixture of a polylactic acid copolymer obtained by ring-opening polymerization of lactide to a polyol and a polylactic acid resin is preferably used, and a nanoalloy mixture having a polyol dispersion domain of less than 1 μm is more preferable.

  The aforementioned nanoalloy means that the island component made of dispersed resin has a diameter of less than 1 μm. As a means for nano-alloying the resin C and the resin D, a method in which the resin C and the resin D are block-copolymerized, and a block copolymer composed of the resin C and the resin D is used as the resin C and / or the resin D. The method of adding is mentioned. If the molecular weight and copolymerization ratio of the block copolymer used in the above method are changed, the effect can be expressed more efficiently. In particular, since the position is easily fixed by increasing the copolymerization ratio of the sea component, localization can be suppressed, and a finer and more uniform dispersion state can be easily created.

  From such a point, it is preferably used in a method in which a foamed agent is impregnated into a mixture obtained by nanoalloying different resin C and resin D within a range where the difference in solubility in the foaming agent exceeds 0% and less than 10%. As the resin, it is preferable to combine a resin selected from a polylactic acid resin as the resin C, a copolymer having a polylactic acid segment as the resin D, a polypropylene resin, and a methacrylic resin.

  Examples of the copolymer having a polylactic acid-based segment include a polyether-polylactic acid copolymer, but are not limited thereto.

  Specific examples of the polyether-polylactic acid copolymer include an ABA type block copolymer obtained by ring-opening polymerization of lactide to polyethylene glycol. The molecular weight of polyethylene glycol is 2000 to 10000, and the molecular weight of the copolymerized polylactic acid segment can be 2000 to 3500.

  In addition, as a foaming agent used, physical foaming agents, such as butane, propane, nitrogen, a carbon dioxide gas, are used suitably. However, since butane and propane are flammable, nitrogen and carbon dioxide are preferable, and carbon dioxide is more preferably used when safety and environmental performance are important.

  Moreover, particles, such as a lubricant and a foam nucleating agent, can be added to the resin foam (A) for the purpose of imparting stability during production, as long as the effects of the present invention are not impaired. Specifically, talc, silica, calcium silicate, wollastonite, kaolin, clay, mica, zinc oxide, titanium oxide, calcium carbonate montmorillonite, zeolite, sodium stearate, magnesium stearate, barium stearate, liquid paraffin, Examples include olefinic wax and erucic acid amide.

  Subsequently, a mixture obtained by impregnating two different components (resin E and resin F) with a difference in solubility in the foaming agent of 10% or more into a nano-alloy is impregnated with the foaming agent and foamed, and then one component (resin F) is decomposed. A manufacturing method will be described. In this method, vacancies (L) are generated with components having high solubility, and then vacancies (S) are generated by decomposing components having low solubility.

  Examples of the decomposition reaction used in this method include photolysis, hydrolysis, thermal decomposition, acid or alkali decomposition, ultraviolet irradiation decomposition, biodegradation by microorganisms, etc., and various methods are used depending on the resin to be decomposed. Can do. For example, if the resin to be decomposed is polymethyl methacrylate, it can be decomposed by irradiating the resin foam with ultraviolet rays, and if it is polylactic acid, it can be decomposed by hydrolysis, biodegradation or the like.

  The resin used for foaming (resin E) is not particularly limited, and the foaming agent is added to a mixture obtained by nanoalloying two different resins in a range where the difference in solubility in the foaming agent exceeds 0% and less than 10%. The same resin (resin C and resin D) as the method of impregnating and foaming can be mentioned. That is, examples of the resin E include polyurethane resins, polystyrene resins, polypropylene resins, polyester resins, polylactic acid resins, polyethylene resins, methacrylic resins, and polycarbonate resins. Moreover, as resin (resin F) used when a void | hole is produced | generated by decomposition | disassembly, it mainly consists of hydroxycarboxylic acids and aliphatic polyesters represented by polyester-type resin, methacrylic-type resin, or polylactic acid-type resin. The biodegradable resin is preferable. In particular, when importance is placed on environmental performance, a polylactic acid resin is preferably used.

  The manufacturing method described above is used when the compatibility of the resin to be mixed (resin E and resin F) is extremely poor, and a compound having an affinity or interaction with both at the interface between the components is used. As a result, the interfacial energy is reduced, and a dispersed form having a larger surface area can be obtained. Examples of the compound used include ethylene bisamide and ethylene bislauric acid amide.

  As for the foaming agent, the same foaming method as that in which the foaming agent is impregnated into a mixture obtained by nanoalloying different two-component resins with a difference in solubility in the foaming agent exceeding 0% and less than 10%. Agents can be used.

  Similarly to the above-described method of impregnating a foaming agent into a mixture obtained by impregnating a two-component resin different in a range where the difference in solubility in the foaming agent exceeds 0% and less than 10% and foams the foaming agent, Resin foam in a production method in which a mixture obtained by nanoalloying two different components (resin E and resin F) having a difference in solubility of 10% or more is impregnated with foaming agent and then foamed, and then one component (resin F) is decomposed In addition, particles such as a lubricant and a foam nucleating agent that impart extrusion stability can be added within a range not impairing the effects of the present invention.

  Although the foaming method of a resin foam (A) is not specifically limited, It can manufacture with the following method. Supply the resin to an extruder equipped with a foaming agent injection device, heat and melt it, inject or add the foaming agent as necessary, and then suddenly release the pressure during extrusion discharge from the resin After the resin and the foaming agent are put into a pressure vessel such as an extrusion foaming method or autoclave that creates a foam by vaporizing the resin, the resin is impregnated with the foaming agent at a predetermined temperature, pressure, and time, and sudden pressure is applied. For example, a batch-type foaming method in which a foam is formed by opening or reheating after cooling the impregnating resin.

  In addition, particles such as a lubricant and a foam nucleating agent that impart extrusion stability can be added to the resin foam (A) described above as long as the effects of the present invention are not impaired. Specifically, talc, silica, calcium silicate, wollastonite, kaolin, clay, mica, zinc oxide, titanium oxide, calcium carbonate montmorillonite, zeolite, sodium stearate, magnesium stearate, barium stearate, liquid paraffin, Examples include olefinic wax and erucic acid amide.

  Next, the gas barrier film (B) will be described.

  As the gas barrier film (B) in the present invention, a gas barrier film having a high barrier property for maintaining a reduced pressure space and a mechanical strength that can withstand external pressure and having a property of being easily sealed is preferably used.

  Specifically, it is preferable to use a laminate film composed of a plastic film having a metal layer. Examples of the metal layer include a metal foil and a metal layer formed by metal vapor deposition, and a known material may be used for these.

  As the metal foil, an aluminum foil is often used. In metal vapor deposition, aluminum, indium, zinc, gold, silver, platinum, nickel, chromium, or oxides such as titanium, zirconium, silicon, and magnesium can also be used. Among them, aluminum having low gas permeability and widely used is preferably used.

  As a method for producing a metal vapor deposition layer, a vacuum vapor deposition method, an EB vapor deposition method, a sputtering method, a physical vapor deposition method such as an ion plating method, a chemical vapor deposition method such as plasma CVD, or the like can be used. From the above, the vacuum evaporation method is particularly preferably used.

  Examples of the resin used for the gas barrier film (B) include polyethylene resins, polystyrene resins, polypropylene resins, polyester resins, polylactic acid resins, methacrylic resins, and polycarbonate resins. In particular, when a heat-insulating material having a low environmental load is desired, an aliphatic polyester resin composed of an aliphatic dicarboxylic acid and a diol or a polyester resin composed of a hydroxycarboxylic acid is preferably used. Specific examples include polybutylene adipate, polybutylene succinate, polybutylene adipate / succinate copolymer, polyhydroxybutyric acid, polycaprolactone, polylactic acid, and polyglycolic acid.

  If the film obtained from the resin is an oriented film that is stretched and oriented in one direction or two orthogonal directions, it is preferably used because the gas barrier property is improved. As a method of stretching and orientation, the film is stretched in one direction by passing a roll with a speed difference, and then the both ends of the film are gripped by a clip on a rail extending in the width direction and then stretched in the width direction of the film. Alternatively, simultaneous biaxial orientation in which the film is blown into a tube shape and simultaneously stretched in the longitudinal direction and the width direction can be mentioned.

  Examples of the method for forming the gas barrier film include a dry laminating method using an adhesive for dry lamination, and an extrusion laminating method in which a part of the gas barrier film is melt-extruded using an olefin resin.

  Next, the heat insulating material (V) will be described.

  As a method for producing a structure in which the resin foam (A) is used as a core material and the whole is covered with a gas barrier film (B), the heat insulating material (V) is square with a size smaller than the size of the gas barrier film (B). After the cut resin foam (A) is stacked in the order of gas barrier film (B) / resin foam (A) / gas barrier film (B), the three sides are heat-sealed, and the pressure is reduced from the other side. A method of instantly heat-sealing and sealing and manufacturing, or a method of heat-sealing and manufacturing the gas barrier film (B) and the resin foam (A) in a reduced-pressure environment in a reduced-pressure facility. The latter production method is preferred in consideration of processability and quality stability.

The degree of vacuum inside the structure in which the resin foam (A) is used as a core material and is entirely covered with the gas barrier film (B) needs to be 10 ⁻⁹ Pa or more and less than 1.01325 × 10 ⁵ Pa. . A degree of vacuum of less than 10 ⁻⁹ Pa is difficult to achieve with a general vacuum pump or turbo molecular pump, and is difficult to manufacture. Moreover, if it is 1.01325 * 10 < ⁵ > Pa or more, the pressure more than atmospheric pressure will be applied and it will be difficult to achieve sufficient heat insulation performance.

As a range in which the ease of production and the heat insulation performance are compatible, the degree of vacuum inside the structure is preferably 10 ⁻³ Pa or more and less than 200 Pa. In particular, when importance is attached to heat insulation performance, 10 ⁻³ Pa or more and less than 10 Pa is preferable, and when importance is placed on ease of production, 10 ⁻¹ Pa or more and less than 200 Pa is preferable.

  Moreover, the adsorbent which adsorb | sucks gas and a water | moisture content can be added to the space of a resin foam (A) and a gas barrier film (B) in the range which does not impair the effect of this invention. Specific adsorbents include zeolite, calcium hydroxide, activated carbon, calcium chloride and the like.

(1) Using an independent bubble ratio dry automatic densimeter “Acpic 1330” (Shimadzu Corporation), the following method was used.
(A) The resin foam (A) was cut into two cubes having a length and width of 25 mm and a thickness of 3 mm.
(B) The geometric volume (Vg) of two cubes was determined from dimensional measurements.
(C) Two legislatures were measured with AccuPick 1330 to determine the sample volume (Vp1).
(D) Cutting was performed three times for each of the two cubes to produce a total of 16 cubes having a length and width of 12.5 mm and a thickness of 1.5 mm.
(E) Sixteen cubes were measured with AccuPick 1330 to determine the sample volume (Vp2).

  Next, the closed cell ratio was determined by the following calculation.

When the volume of open bubbles is (Voc) and the volume of closed cells opened in the process of sample preparation is (Vcc), the volume data (Vp1, Vp2) and the open cell ratio (Co) obtained during measurement are obtained from ASTM. Can be rewritten as:
Vp1 = Vg−Voc−Vcc (a)
Vp2 = Vg−Voc−2Vcc (b)
In order to erase Vcc from both equations, 2 × (a)-(b)
2Vp1-Vp2 = Vg-Voc
∴Voc = Vg-2Vp1 + Vp2
As a result, the open cell ratio (Co) is Co = Voc / Vg × 100 (%).
Here, since the closed cell ratio (Cc) cannot be obtained unless the true density (D) of the sample is known, the volume of only closed cells is (Vc), and the sample weight is (W).
Vc = Vg-W / D-Voc
Therefore, the closed cell ratio (Cc) is obtained as follows.
Cc = Vc / Vg × 100 (%)
(2) Hole Occupancy (S) Area Occupancy Ratio As an indicator of a characteristic structure in which different hole diameters such as holes (L) and holes (S) are mixed, area occupancy (holes (S) is foamed) The ratio of the area to the cross-sectional area of the body) was used.
The area occupancy was determined as follows.

  Here, the hole (S) is a hole having a diameter in terms of a circle of 0.01 μm or more and less than 1 μm.

  a) Using a scanning electron microscope (FE-SEM) manufactured by JEOL Ltd., the cross section of the resin foam was expanded to a range where the measurement image range on one side was 10 μm, and an image was captured.

  b) A transparent sheet (OHP sheet or the like) was placed on the photographed photo, and the hole (L) was painted on it with black ink.

  c) The image processed by b) is taken into an image processing apparatus (Pierce Co., Ltd., product number: PIAS-II), and the dark color portion and the light color portion are identified (whether or not they are painted with black ink). Then, using “FRACTAREA (area ratio)” in the image analysis calculation function, the area of the dark color portion, that is, the area (La) of the hole (L) was obtained.

  e) Next, the hole (S) was painted with black ink using a transparent sheet in which the hole (L) was painted with black ink.

  f) The image processed by b) is taken into an image processing apparatus (Pierce Co., Ltd., product number: PIAS-II), and the dark color portion and the light color portion are identified (whether or not they are painted with black ink). Then, using “FRACTAREA (area ratio)” in the image analysis calculation function, the area of the dark color portion, that is, the area of holes (L) + holes (S) (La + Sa) was obtained. And the area (Sa) of the void | hole (S) was calculated | required from following Formula.

Hole (S) area = area (La + Sa) −area (La)
g) The area occupation ratio of the pores (S) was calculated by the following formula.

Hole (S) area occupancy = area (Sa) / {(area of entire image−area (La)) × 100
(3) Porosity (X) The porosity (X) was calculated by the following equation using the area (La + Sa) obtained in the image analysis method of the area occupancy ratio of the pores (S) in the previous section (1).
Value (X) = {Area of the entire image−Area (La + Sa)} / Area of the entire image (4) Thermal conductivity Measurement was performed using a 7 mmφ sensor of a thermal conductivity measuring device manufactured by Hot Disk. The measurement location measured 5 places of the center part and four corners of a heat insulating material (V), and made each average the heat conductivity.
(5) Change in performance The thermal conductivity (Vλ1) immediately after the manufacture of the heat insulating material sample is measured, put into a pressure vessel, and pressurized to 0.2 MPa using compressed air in an atmosphere of temperature 40 ° C. and humidity 65% RH. did. After 30 days, the heat insulating material (V) was taken out, and the thermal conductivity (Vλ2) was measured. The performance change at that time was defined by the following formula as a performance change value.
Performance change value = Vλ1 / Vλ2
If the performance change value is 1, it means that there is no performance change. The following evaluation was performed using the performance change value.
◎: Performance change value is 0.5 or more and 1 or less ○: Performance change value is 0.25 or more and less than 0.5 ×: Performance change value is less than 0.25 (6) Production method of resin foam by extrusion foaming Supercritical Using a tandem extruder equipped with a carbon dioxide supply line, the pellets were supplied to the first extruder, melted at a temperature of 140 to 220 ° C., and then supercritical carbon dioxide was supplied at the tip of the extruder. Next, after lowering the temperature to 100 to 150 ° C. with a second extruder and sufficiently impregnating the gas, the hollow cylindrical resin foam is discharged into the atmosphere from a circular die and cooled by a mandrel with a cutter. The cylinder was opened to obtain a sheet-like foam.
(7) Method for confirming presence / absence of pores (L) and pores (S) and number density Using a scanning electron microscope (FE-SEM) manufactured by JEOL Ltd., the cross section in the thickness direction of the resin foam is 1000. Captured an image that was doubled. The presence or absence of holes (L) was confirmed from the image.

Further, a range in which the number of holes (L) was about 20 to 40 was trimmed from the captured image, and the number of bubbles in the holes (L) therein was measured. It was calculated number density by multiplying the numbers so that the mm ² to several measured.

  Next, an image magnified 20000 times around the bubble wall surface was captured. And from this image, the presence or absence of pores (S) was confirmed.

Further, a range in which the number of holes (S) was about 20 to 40 was trimmed from the captured image, and the number of bubbles in the holes (S) therein was measured. The number density was calculated by multiplying the measured number by a number so as to be μm ² .
(8) Hole diameter of hole (L) and hole (S) Using a scanning electron microscope (FE-SEM) manufactured by JEOL Ltd., an image obtained by enlarging the cross section in the thickness direction of the resin foam 1000 times is captured. It is. The captured image was divided into four blocks, top, bottom, left, and right, and holes of 1 μm or more and less than 100 μm per block were selected, measured from the scale of the microscope, and the average of the total number was the hole diameter of the holes (L).

Next, an image magnified 20000 times around the bubble wall surface was captured. The captured image was divided into four blocks, top, bottom, left, and right, and holes of less than 1 μm per block were selected, measured from the scale of the microscope, and the average of the total number was the hole diameter of the holes (S).
(9) The resin and metal used are described below.
Polyethylene glycol: Sanyo Chemical Co., Ltd. “PEG-6000S” number average molecular weight 8300
Polylactic acid: weight average molecular weight 150,000, L-form 96%
Polystyrene: “G9401” manufactured by PS Japan, MFR = 2.2
Glass wool: Asahi Fiber Glass Co., Ltd. “Matte Ace Plus”
Aluminum: “High-purity aluminum wire” manufactured by Nippon Light Metal Co., Ltd.
Continuous foaming urethane: Polyurethane foam was obtained using polypropylene oxide and organic polyisocyanate as a catalyst, dibutyltin laurate as a catalyst, a silicon surfactant as a foam stabilizer, calcium stearate as a foam communicating agent, and cyclopentane as a foaming agent.
[Example 1]
Polyethylene glycol 0.85 kg was charged into a sealed container equipped with a vacuum line and a heating device, dehydrated under reduced pressure at 140 ° C. for 30 minutes, and then 0.5 kg of L-lactide was charged. Next, the atmosphere in the container was replaced with an inert gas, and 10 g of tin (II) 2-ethylhexanoate was added while melting and stirring polyethylene glycol and lactide, and the mixture was stirred at 160 ° C. in an inert atmosphere for 3 hours. After that, 7.5 g of dimethyl phosphate was added as a catalyst deactivator and stirred for 30 minutes. Next, in order to remove volatiles, the pressure was reduced to 140 ° C. for 2 hours, and the pressure was returned to atmospheric pressure with an inert gas to obtain a PLA-PEG-PLA copolymer having a molecular weight of 13,500.

  Using the obtained PLA-PEG-PLA copolymer 0.25 kg, polylactic acid 4.72 kg, talc 0.03 kg, according to the above-mentioned “(6) Method for producing resin foam by extrusion foaming”, a width of 250 mm, A resin foam (A) having a thickness of 3 mm was obtained.

As the gas barrier film (B), a laminate film composed of a polyethylene terephthalate film having a thickness of 12 μm for the outermost layer, an aluminum foil having a thickness of 6 μm for the intermediate layer, and a linear low density polyethylene film having a thickness of 50 μm for the heat bonding layer was used. .
Next, four resin foams (A) were cut out at 100 mm square, and two gas barrier films (B) were cut out at 250 mm square. Four resin foams (A) are stacked in the thickness direction and sandwiched between two gas barrier films (B), and then 1 g of calcium hydroxide is added as an adsorbent, and the three sides of the resin foam are sealed with an impulse sealer. Heat sealed. Next, using a small vacuum packaging machine (FVCII: manufactured by Furukawa Seisakusho) equipped with a pressure gauge and a pressure regulating valve so that the degree of decompression can be adjusted, the decompression degree is reduced to 10 ⁻¹ Pa and the vacant side is heated. A heat insulating material (V) was prepared by sealing.
[Example 2]
Using the same resin foam (A) as in Example 1 and a gas barrier film (B), a heat insulating material (V) was prepared at a reduced pressure of 50 Pa.
Example 3
Using a polystyrene resin, a resin foam (A) having a width of 250 mm and a thickness of 3 mm was obtained by the above-mentioned “(6) Method for producing resin foam by extrusion foaming”.
The gas barrier film (B) and the heat insulating material (V) were prepared in the same manner as in Example 1.
Example 4
After obtaining the resin foam (A) by the same method as in Example 3 and the gas barrier calcium (B) by the same method as in Example 1, a heat insulating material (V) was prepared at a pressure of 50 Pa.
[Comparative Example 1]
A heat insulating material was prepared in the same manner as in Example 1 using the continuous foamed urethane as a core material and the gas barrier film (B) used in Comparative Example 1.
[Comparative Example 2]
A heat insulating material was prepared in the same manner as in Comparative Example 1 except that glass wool was used as the core material.
[Comparative Example 3]
A heat insulating material was created at a pressure of 50 Pa using the continuous foamed urethane used in Comparative Example 1 as a core material and the gas barrier film (B) used in Comparative Example 1.

(Abbreviation notation)
PLA: Polylactic acid PET: Polyethylene terephthalate PS: Polystyrene PEG: Polyethylene glycol PU: Polyurethane PE: Polyethylene Al: Aluminum

Claims (3)

A structure heat insulating material comprising a closed cell resin foam (A) and a gas barrier film (B), wherein the resin foam (A) is used as a core and the whole is covered with a gas barrier film (B). The heat insulating material (V) whose decompression degree inside is 10 < ^-9 > Pa or more and less than 1.01325 * 10 < ⁵ > Pa.   The resin foam (A) has pores (L) having an average pore diameter of 1 μm or more and 1000 μm or less, and pores (S) having an average pore diameter of 0.01 μm or more and less than 1 μm, and the porosity (X) is 80% or more. The heat insulating material (V) according to claim 1, characterized in that: The resin foam empty number density of the holes (L) are 10 ^two (A) / mm ² or more 10 ⁷ / mm ² or less, the number density of vacancies (S) is 10 ² / [mu] m ² or more 10 ⁷ The heat insulating material (V) according to claim 2, wherein the heat insulating material is V / μm ² or less.