JP2021109435A - Aerogel laminate structure and method for producing the same - Google Patents

Abstract

To provide an aerogel laminate structure that excels in heat insulation and flexibility or moldability.SOLUTION: An aerogel laminate structure has an aerogel composite material with the inside of a first foam filled with aerogel, and a second foam and/or fiber provided at least on one side of the aerogel composite material. The first foam is an open-celled resin foam and has a density of 0.015-0.300 g/cm3.SELECTED DRAWING: Figure 1

Description

The present invention relates to an airgel laminated structure and a method for producing the same.

Ceiling materials are installed inside the roofs of automobiles, railroad cars, aircraft, and ships. Since this ceiling material is required to have various functions such as heat insulating property, heat insulating property, sound absorbing property, and decorative property, not only the material alone but also a plurality of materials such as foam and fiber are laminated.

For example, in automobile applications, there are ceiling materials that combine polyurethane foams and fibers, and they are called molded ceilings.

As the heat insulating material for the ceiling material, the polyurethane foam disclosed in Patent Documents 1 to 3 and the vacuum heat insulating material disclosed in Patent Document 4 are used.

Patent No. 5626904 Japanese Unexamined Patent Publication No. 2007-331673 Japanese Unexamined Patent Publication No. 2003-260718 Special Table 2011-5693

However, although the general-purpose polyurethane foam has excellent sound absorption and insulation properties, the heat insulation performance and heat insulation performance are not so high, so that the heat insulation performance of the entire laminate is low. In order to exhibit high heat insulation performance, it is necessary to thicken the foam or fiber, so that the passenger compartment space becomes narrow. Further, since the rigid polyurethane foam having excellent heat insulating performance lacks flexibility, the degree of freedom in processing is limited.

Further, the vacuum heat insulating material having high heat insulating performance has a problem that it lacks flexibility or moldability, the degree of vacuum decreases with time, and the heat insulating performance deteriorates.

Therefore, an object of the present invention is to provide an airgel laminated structure having excellent heat insulating properties and flexibility or molding processability.

The present inventors have conducted diligent research and found that the above-mentioned problems can be solved by an airgel laminated structure containing a specific airgel composite material, and completed the present invention. That is, the present invention is as follows.

The present invention (1)
An airgel laminated structure containing an airgel composite material in which the inside of the first foam is filled with airgel, and a second foam and / or fiber body provided on at least one side of the airgel composite material. hand,
The first foam is an airgel laminated structure characterized by being an open-cell resin foam and having a density of 0.015 to 0.300 g / cm ^3.
The present invention (2)
The first foam is an open cell resin foam with an epidermis having a foam layer having open cells and a breathable epidermis layer formed on two opposing surfaces of the foam layer. ,
The epidermis layer contains open cells that reach the surface of the epidermis layer.
The average cell diameter RA of open cells observed from the surface of the epidermis layer from the normal direction of the surface of the epidermis layer, and the average cell diameter RB of the open cells of the foam layer in a cross section perpendicular to the surface of the epidermis layer. , The ratio (RA / RB) of is 1/1000 to 1/2, which is the airgel laminated structure of the invention (1).
The present invention (3)
The airgel laminated structure of the invention (2), wherein the air permeability of the first foam is 0.01 to 300 ^{cm 3} / cm ^{2 / sec.}
The present invention (4)
The airgel laminated structure of the invention (2) or (3), wherein the first foam is selected from a polyolefin foam, a polyurethane foam, an acrylic foam, an acrylonitrile-butadiene rubber foam, and a silicone foam. Is.
The present invention (5)
The first foam is an open cell resin foam selected from a melamine foam, a polyimide foam, or a polyurethane foam obtained by compression molding.
The first foam has an airgel laminated structure according to the invention (1), which has a density of 0.015 ^{to 0.200 g / cm 3} and an air permeability of 0.5 to 300 ^{cm 3} / cm ^{2 / sec.} Is.
The present invention (6)
The airgel laminated structure according to any one of the inventions (1) to (5), wherein the thickness of the first foam is 0.03 to 50.0 mm.
The present invention (7)
The airgel laminated structure according to any one of the inventions (1) to (6), wherein the fiber body is a carbon fiber woven fabric.
The present invention (8)
The airgel laminated structure of the invention (7), wherein the fiber body is a fiber reinforcing material obtained by impregnating a carbon fiber woven fabric with a thermosetting resin and curing the fiber body.
The present invention (9)
It is an airgel molded product obtained by thermoforming the airgel laminated structure according to any one of the inventions (7) to (8).
The present invention (10)
A ceiling material containing the airgel laminated structure according to any one of the inventions (1) to (8).
The present invention (11)
The method for manufacturing a ceiling material including the airgel laminated structure of the invention (9).
A method for producing a ceiling material, which comprises a step of laminating the second foam and / or the fiber on at least one side of the airgel composite.

According to the present invention, it is possible to provide an airgel laminated structure having excellent heat insulating properties and flexibility or molding processability. According to the present invention, not only has excellent heat insulating properties at the initial stage, but also excellent flexibility or molding processability, so that heat insulating performance during processing into a product shape or after mounting on a product over time. Deterioration can be prevented.

It is a cross-sectional photograph of the open cell resin foam with a skin. It is a photograph from the normal direction of the surface of the epidermis layer of the open cell resin foam with an epidermis.

Hereinafter, the airgel laminated structure and the method for producing the same according to the present invention will be described in detail.

In the present invention, the term "normal pressure" means a pressure that is neither depressurized nor pressurized. Further, under reduced pressure means a state in which the pressure is artificially reduced from the atmospheric pressure.

In the present invention, the density is the apparent density measured in accordance with JIS K7222: 2005 "Foam plastics and rubber-How to determine the apparent density".

In the present invention, the airgel composite material is a foamed base material filled with airgel, but the foamed base material before filling with airgel and the foamed base material after filling with airgel are treated as the same. , Either explanation may be omitted or replaced with the other explanation.

In the following, foams, resin foams, foamed base materials, etc. may be used without distinction.

Powder removal usually means that the airgel powder is desorbed from the airgel composite material in the manufacturing process of the airgel laminated structure, but it means that the airgel powder is desorbed from the airgel laminated structure itself. May be good.

<<<<<< Aerogel laminated structure >>>>>>
The airgel laminated structure includes an airgel composite and a second foam and / or fiber provided on at least one side of the airgel composite. Hereinafter, the second foam and / or fiber contained in the airgel laminated structure will be referred to as an outer layer.

Each layer included in the airgel laminated structure may be laminated via an adhesive layer or the like, or may be directly laminated without an adhesive layer or the like. For example, when a certain layer is made of a thermoplastic material, it is possible to directly laminate the layers by heat-melting a part of the certain layer and then bringing the other layer into contact with each other.

When each layer of the airgel laminated structure is laminated via the adhesive layer, conventionally known adhesives can be used as the adhesive constituting the adhesive layer.

External layers may be provided on both sides of the airgel composite.

The airgel laminated structure may contain a plurality of first foams.

The airgel laminated structure may have other layers as long as the effects of the present invention are not impaired.

<<<<< Airgel Composite >>>>>
The airgel composite includes a first foam and an airgel filled inside the first foam.

The airgel is not particularly limited as long as it is a low-density dry gel. It includes not only airgels obtained by the supercritical fluid drying method, but also xerogels obtained by a normal drying process, cryogels obtained by freeze-drying, and the like.

As the airgel, any suitable airgel component can be used. For example, you can choose from inorganic airgels such as silica aerogels and alumina aerogels, organic aerogels such as resorcinol formaldehyde aerogels (RF aerogels), cellulose nanofiber aerogels (CNF aerogels), carbon aerogels, and mixtures thereof. can. As the airgel, _{a silica airgel containing silica (SiO 2} ) can be preferably used.

In the airgel, a sol solution which is a precursor of airgel is filled in an open cell resin foam, and the foam is gelled and dried to form an airgel.

The average filling rate (the ratio of the volume of the filled aerogel to the bubbles) occupying the individual bubbles (cells) contained in the first foam of the airgel is not particularly limited, but is 50% to 100%. 70% to 100% is more preferable, and 90% to 100% is more preferable. When the average filling rate of the airgel is within such a range, the airgel composite has excellent heat insulating properties.

The first foam constituting the airgel composite material is an open-cell resin foam and has a density of 0.015 to 0.300 g / cm ³ .

The first foam is an open-cell resin foam having an open-cell structure. By using the open cell resin foam as the first foam, it is possible to sufficiently fill the inside of the foam with airgel, and it is possible to achieve excellent heat insulating properties. More specifically, the air permeability of the first foam is 0.01 cm ³ / cm ² / sec or more, 0.5 cm ³ / cm ² / sec or more, 10 cm ³ / cm ² / sec or more, or 25 cm. ^{It is preferably 3} / cm ² / sec or more. The upper limit of the air permeability of the first foam is, for example, 300 cm ³ / cm ² / sec. Such an air permeability can be measured by a method described later.

The first foam has a density of 0.015 to 0.300 g / cm ³ . Density of the first foam, 0.020 g / cm ³ or more, 0.030 g / cm ³ or more, 0.040 g / cm ³ or more, 0.050 g / cm ³ or more, 0.075 g / cm ³ or more, 0 .100g / cm ³ or more, may be 0.120 g / cm ³ or more, also, 0.275 g / cm ³ or less, 0.250 g / cm ³ or less, 0.240 g / cm ³ or less, 0.230 g / cm ³ hereinafter, 0.220 g / cm ³ or less, 0.210 g / cm ³ or less, 0.200 g / cm ³ may be less. By setting the density of the first foam in this range, it is possible to obtain an airgel composite material having excellent flexibility while controlling the filling amount of airgel so as to exhibit excellent heat insulating properties.

The resin component constituting the first foam is not particularly limited, but is olefin resin, acrylic resin, urethane resin, vinyl acetate resin, vinyl chloride resin, epoxy resin, rubber, silicone resin, melamine resin, and imide resin. It can be a known resin component such as.

The thickness of the airgel composite material (or the first foam) can be 0.03 mm to 50.0 mm. The thickness may be 0.05 mm or more, 0.10 mm or more, 0.20 mm or more, 0.50 mm or more, 0.75 mm or more, 1.00 mm or more, and 40.0 mm or less, 30.0 mm or less, 20. It may be 0.0 mm or less, 10.0 mm or less, 5.00 mm or less, 4.00 mm or less, 3.00 mm or less, 2.00 mm or less.

When the water-dispersible resin is used as a raw material in the foam forming step described later, 0.2 mm to 2.0 mm is preferable, and 0.5 mm to 1.5 mm is more preferable. When the water-dispersible resin is not used as a raw material, 0.5 mm to 50.0 mm is preferable, and 1.0 mm to 30.0 mm is more preferable. When the thickness of the airgel composite material is within such a range, defects such as pin poles are unlikely to occur during manufacturing, and the flexibility can be increased.

When the first foam contains a skin layer described later, the thickness of the airgel composite material indicates the sum of the thickness of the skin layer and the thickness of the foam layer.

Hereinafter, the first preferred form (first form) and the second preferred form (second form) will be described in detail as the airgel composite material which has less powder falling off and is expected to improve the heat insulating property and the like. .. It should be noted that the present invention also includes a configuration in which the matters described for the airgel composite material according to the first form and the matters described for the airgel composite material according to the second form are appropriately combined.

<<< Airgel composite material according to the I form >>>
The aerogel composite material according to the first embodiment is an open cell resin with a skin, which has a foam layer having open cells and a breathable skin layer formed on two opposing surfaces of the foam layer. In the foam (hereinafter, may be simply abbreviated as "resin foam"), the skin layer contains open cells that reach the surface of the skin layer, and the surface of the skin layer is continuously observed from the normal direction. The ratio (RA / RB) of the average cell diameter RA of the bubbles to the average cell diameter RB of the open cells of the foam layer in the cross section perpendicular to the surface of the epidermis layer is 1/1000 to 1/2. , An aerogel composite material in which aerogel is filled inside the open cells of the open cell resin foam with a skin.

The average cell diameter ratio is the compounding conditions described later (the amount of the anionic surfactant to be added, the ratio of the main agent and the curing agent, the amount of the organic foaming agent, the foaming aid, and the nucleating agent. ) And molding conditions (stirring rate, drying temperature), etc., can be adjusted. For example, if the amount of the anionic surfactant as a foaming agent is reduced, the average cell diameter RB of the open cells of the foam layer in the cross section perpendicular to the surface of the skin layer becomes large, so that the average cell diameter ratio (RA / RB) tends to be small. On the other hand, when the drying temperature at the time of molding is raised, the average cell diameter RA of open cells observed from the normal direction on the surface of the skin layer becomes large, so that the average cell diameter ratio (RA / RB) tends to be large. .. Further, the average cell diameter ratio (RA / RB) tends to increase by increasing the blending amount of the nucleating agent. When the average cell diameter ratio is in such a range, the airgel composite material has excellent heat insulating properties by having excellent powder falling prevention properties. That is, when the amount of powder falling off is small, the aerosilica gel, which is a heat insulating material, is less likely to fall out from the foamed body, and high heat insulating properties can be maintained as an airgel composite material. Details of the average cell diameter ratio will be described later.

Examples of the nucleating agent include powders of inorganic compounds such as wet silica, dry silica, talc, mica, and diatomaceous earth; aluminum oxide, titanium oxide, zinc oxide, magnesium oxide, magnesium hydroxide, aluminum hydroxide, calcium hydroxide, and carbonic acid. Metal soaps such as potassium, calcium carbonate, magnesium carbonate, potassium sulfate, barium sulfate, glass beads, polytetrafluoroethylene, calcium tertiary phosphate, magnesium pyrophosphate, calcium stearate, zinc stearate, magnesium stearate; ethylene bisstearic acid Amido compounds such as amide, methylenebis stearic acid amide, stearic acid amide, 12-hydroxystearic acid amide; fatty acid glycerides such as stearic acid triglyceride, stearic acid monoglyceride and the like. These nucleating agents may be used alone or in combination of two or more.

Further, when the amount of powder falling off is small, the heat insulating effect can be maintained, which is considered to contribute to the improvement of flame retardancy.

<< Open cell resin foam with epidermis >>
The open cell resin foam with a skin includes a foam layer having open cells as described above and a breathable skin layer formed on two opposing surfaces of the foam layer. Further, as the open cell resin foam with a skin, a commercially available one can be used as long as the effect of the present invention is not impaired.

The foam layer and the epidermis layer are, for example, a foamed aqueous liquid medium (foamed aqueous liquid medium) or a mixed silicone in the foam forming step in the method for producing an aerogel composite material using a non- polyolefin foam. The resin foam raw material is supplied onto a PET sheet that has been molded, and is formed into a sheet shape or the like that matches the desired thickness of the resin foam by, for example, a known means such as a doctor knife or a doctor roll. At this time, the surface of the foam layer in contact with the PET sheet and the coating tool such as the doctor knife is altered to form the epidermis layer. Therefore, the foam layer and the epidermis layer are integrated.

Therefore, the open cells contained in the foam layer and the open cells contained in the epidermis layer communicate with each other, and the foam layer also has air permeability. That is, even as an open cell resin foam with a skin, it has breathability. Breathability will be described later.

The epidermis layer can also be formed by preparing a foam layer having open cells and then heat-treating the foam layer having open cells with a heat press machine or a heat roll machine.

The shape, size, and thickness of the open cell resin foam with a skin are the same as those of the airgel composite material.

Further, the material of the open cell resin foam with a skin can include at least one of an olefin resin, an acrylic resin, a urethane resin, a vinyl acetate resin, a vinyl chloride resin, an epoxy resin, a rubber, and a silicone resin.
The details of the material will be described in detail in the description of the manufacturing method described later.

More specifically, the open cell resin foam with a skin is preferably selected from a polyolefin foam, a polyurethane foam, an acrylic foam, an acrylonitrile-butadiene rubber foam, and a silicone foam.

Since the open cell resin foam with a skin is excellent in flexibility and chemical resistance, it is preferable to use a polyolefin foam. Further, a polyurethane foam is also suitable because it has excellent flexibility and low compression residual strain. Further, it is also preferable to use an acrylic foam because it has excellent strength, light weight, and heat insulation. In addition, since it is excellent in flame retardancy and heat resistance, it is also preferable to use a silicone resin foam and a silicone rubber foam.

The porosity of the open cell resin foam with skin is calculated by dividing the apparent density of the open cell resin foam with skin after foaming by the density of the unfoamed raw material resin and subtracting this divisor from 1 to obtain a percentage. do. The measurement of apparent density conforms to JIS K7222: 2005 "Foam Plastics and Rubber-How to Obtain Apparent Density".

The porosity is preferably high because it can increase the filling amount of airgel contained in the airgel composite material. The larger the filling amount of airgel having high heat insulating property, the higher the heat insulating property of the airgel composite material can be.

The porosity is not particularly limited as long as the effect of the present invention is not impaired, but for example, the porosity can be 50 to 99%, preferably 65 to 99%, and 85 to 99%. Is more preferable. When the porosity is within such a range, a sufficient amount of airgel can be filled in the open cell resin foam with a skin, so that the airgel composite material is lightweight and has excellent heat insulating properties. Can be.

<Effervescent layer>
The foam layer has open cells. Further, in the open cells, the cells are connected to each other by a communication through hole.

The average cell diameter (RB) of the open cells in the cross section perpendicular to the surface of the epidermis layer is not particularly limited, but can be, for example, 5 μm to 300 μm, preferably 5 μm to 200 μm, and 5 μm to 100 μm. More preferably. When the average cell diameter of the open cells contained in the foam layer is within such a range, the sol solution can be easily filled by the capillary phenomenon even under normal pressure in the sol solution filling step described later, and the process time. Is shortened.

Further, the size of the airgel contained in the open cells is restricted by the average cell diameter of the open cells, and the size of the airgel is also the same.

Since airgel is extremely brittle, it is easily broken when defects such as cracks are present. The smaller the size of the airgel, the lower the probability that the defect will be present, so that the formed airgel is less likely to be damaged.

Therefore, when the average cell diameter of the open cells is within such a range, the size of the airgel can be reduced, so that the probability that the airgel has a defect can be reduced, and the breakage of the airgel, that is, powder dropping can be reduced. It becomes possible to do.

Further, if the apparent density of the open cell resin foam is the same, the number of barriers can be increased as the cell diameter is smaller. Increasing the number of barriers is effective against radiation, and the thermal conductivity of the open-cell resin foam is lowered, so that the thermal conductivity of the airgel composite is also lowered.

The average cell diameter of the foam layer can be measured by the following method.
A cell photograph of a cross section of the resin foam is taken using a scanning electron microscope (SEM, manufactured by KEYENCE CORPORATION, VHXD-500). Then, each cell diameter is measured using the image processing software Image-ProPLUS (manufactured by Media Cybernetics, 6.3 ver). More specifically, the contrast is adjusted in order to read the SEM image and recognize the cell by the contrast. Next, the shape of the cell is read by image processing (the shape is recognized as it is, not a perfect circle). Next, select "diameter (average)" as the measurement item. Next, the diameter passing through the center of gravity of the object is measured in increments of 2 degrees, and the average value is used to calculate the diameter of each cell.

The average diameter of the communication through holes is preferably large in order to fill the raw material solution of the gel, but is preferably small in order to suppress powder falling of the airgel. The average diameter of the communication through holes is preferably 30 μm or less, more preferably 20 μm or less, and further preferably 10 μm or less. The lower limit of the average diameter of the communication through holes is not particularly limited as long as it can be filled with the raw material solution of the gel, but can be, for example, 0.5 μm or more. When the average diameter of the communication through holes is within such a range, when the airgel composite material is cut or the airgel composite material is bent, the airgel does not fall off and the powder falling prevention property can be improved.

The average diameter of the communication through holes can be measured using a through pore diameter measuring device (palm poromometer) sold by Seihwa Digital Image. Specifically, the average diameter of the communication through holes can be obtained by averaging the values measured by the measuring device with respect to the diameters of at least 20 or more communication through holes randomly selected.

The cell density of the foam layer in the cross section perpendicular to the surface of the epidermis layer is not particularly limited, but can be 10 pieces / mm ² to 200 pieces / mm ² and 20 pieces / mm ^{2 to} 170 pieces / mm ^2. Is preferable, and 40 pieces / mm ^{2 to} 150 pieces / mm ² is more preferable. When the cell density of the foam layer is within such a range, the airgel composite material can be sufficiently filled with airgel and has excellent heat insulating properties.

Here, the cell density is the number of cells (the number of open cells) per unit cross-sectional area included in an arbitrary area of the cross section perpendicular to the surface of the epidermis layer.

The cell density in the cross section perpendicular to the surface of the epidermis layer of the foam layer can be measured by the following method.
A cell photograph of a cross section of the resin foam is taken using a scanning electron microscope (SEM, for example, VHXD-500 manufactured by KEYENCE CORPORATION). Then, using image processing software (for example, Image-ProPLUS (manufactured by Media Cybernetics, 6.3 ver)), the number of cells is measured. More specifically, the contrast is adjusted in order to read the SEM image and recognize the cell by the contrast. Next, the number of cells is read by image processing. The cell density is defined as the area of the cross section of the resin foam in the cross-sectional photograph used for observation, divided by the number of measured cells.

<Epidermis layer>
The epidermis layer is present on two opposing surfaces of the foam layer. As described above, in the epidermis layer, when the foamed aqueous liquid medium is supplied onto the release sheet and molded into a sheet shape or the like, the surface of the foam layer that comes into contact with the PET sheet and the coating tool is denatured. Is formed.

The thickness of the epidermis layer is not particularly limited, but can be, for example, 0.01 to 30 μm, preferably 0.01 to 15 μm, and more preferably 0.01 to 10 μm. When the thickness of the epidermis layer is within such a range, the powder falling prevention property is enhanced.

Further, the epidermis layer contains open cells, and the open cells include those reaching the surface of the epidermis layer. Therefore, the epidermis layer can permeate the outside air. That is, it is breathable.

Further, the open cells contained in the epidermis layer and the open cells contained in the foam layer are connected by communication through holes, and the fluid such as outside air is contained in the open cells contained in the epidermis layer and the foam layer. It is possible to go back and forth between the open air bubbles.

Here, although the air permeability of the epidermis layer alone cannot be measured, it can be determined whether or not the epidermis layer has air permeability by measuring the air permeability of the open cell resin foam with the epidermis through the surface of the epidermis layer. The method for measuring the air permeability of the open cell resin foam with a skin can be measured by a known method and is not particularly limited. For example, it can be measured by using the method described in JIS L1096-7: 2010 "Fabric test method for woven fabrics and knitted fabrics: Method A (Frazier type method)".

Breathability means that the measured air permeability (or air permeability) of the open cell resin foam with skin is 0.01 cm ³ / cm ² / sec or more. In this case, the epidermis layer shall also be breathable.

The air permeability of the open cell resin foam with a skin is preferably 0.1 cm ³ / cm ² / sec or more, 0.5 cm ³ / cm ² / sec or more, or 10 cm ³ / cm ² / sec or more. In particular, in the case of 10 cm ³ / cm ² / sec or more, the airgel composite material does not need to be evacuated for a long time in the sol solution filling step described later, and can be an efficient production method. Further, the upper limit of the air permeability is not particularly limited because the higher the air permeability, the better, but in general, in the case of an open cell resin foam, it can be 300 cm ³ / cm ² / sec.

The ratio of the average cell diameter RA of the open cells contained in the epidermis layer observed from the normal direction of the surface of the epidermis layer to the average cell diameter RB of the open cells of the foam layer in the cross section perpendicular to the surface of the epidermis layer (RA / RB). ) Is 1/1000 to 1/2, preferably 1/100 to 1/2, 1/30 to 1/2, 1/10 to 1/2, or 1/10 to 1/3. be. When the ratio of the average cell diameter is within such a range, the airgel composite material has a high powder falling prevention property, and has excellent heat insulating properties and flame retardancy.

The average cell diameter (RA) observed from the normal direction of the surface of the epidermis layer of the open cells contained in the epidermis layer is not particularly limited, but can be, for example, 1 μm to 150 μm, preferably 1 μm to 100 μm. More preferably, 1 μm to 50 μm. When the continuous cell diameter contained in the epidermis layer is within the above ratio and the above range, airgel powder can be prevented from falling off and the heat insulating property is not deteriorated.

Here, the average cell diameter observed from the normal direction of the surface of the epidermis layer of the open cells contained in the epidermis layer can be measured by the following method.
A cell photograph of a cross section of the resin foam is taken using a scanning electron microscope (SEM, for example, VHXD-500 manufactured by KEYENCE CORPORATION). Then, each cell diameter is measured using image processing software (for example, Image-ProPLUS (manufactured by Media Cybernetics, 6.3 ver)). More specifically, the contrast is adjusted in order to read the SEM image and recognize the cell by the contrast. Next, the shape of the cell is read by image processing (the shape is recognized as it is, not a perfect circle). Next, select "diameter (average)" as the measurement item. Next, the diameter passing through the center of gravity of the object is measured in increments of 2 degrees, and the average value is used to calculate the diameter of each cell.

<< Characteristics of airgel composite material >>
<Apparent density>
The apparent density of the airgel complex can be measured by a known method and is not particularly limited. For example, it can be measured by a method according to JIS K7222-2005 "Foam plastics and rubber-How to obtain apparent density".

<Powder drop rate>
The powder removal rate of the airgel composite material can be measured by a known method and is not particularly limited. For example, it is possible to perform the fir test described in JIS K6404-6: 1999 "Rubber-pulled cloth / plastic-pulled cloth test method-Part 6: Fir test" and measure the mass before and after the test. ..

Specifically, the test piece is 10 mm × 50 mm, the thickness is arbitrary, the test piece interval is 20 mm, the stroke interval is 40 mm, and the compression load is 200 gf. Calculate the drop rate. The powder removal rate (%) is calculated by (weight before test (g) -weight after test (g)) / weight before test (g) x 100. The larger the powder drop rate, the more airgel falls off.

<Thermal conductivity>
The thermal conductivity of the airgel complex can be measured by a known method and is not particularly limited. For example, JIS A1412-1: 1999 "Method for measuring thermal resistance and thermal conductivity of thermal insulating material-Part 1: Protective heat plate method (GHP method)", JIS A1412-2: 1999 "Thermal resistance of thermal insulating material" And the method for measuring thermal conductivity-Part 2: Heat flow metering method (HFM method) "can be measured.

Specifically, the thermal conductivity is measured using a heat flux meter with the upper plate temperature set to 15 ° C and the lower plate temperature set to 35 ° C. The environmental temperature is not particularly limited, but is normal temperature and normal pressure. The thickness of the sample used in the test is 5 mm or more, and if the thickness of the test sample is less than 5 mm, the test samples are laminated and the thermal conductivity is measured to evaluate the heat insulating performance.

The thermal conductivity is preferably 0.020 W / m · K or less, more preferably 0.018 W / m · K or less, and even more preferably 0.016 W / m · K or less.

<<< Manufacturing method of airgel composite material according to the I form >>>
The airgel composite material according to the first form can be produced as follows.

The method for producing the airgel composite material is a sol solution filling step of filling the open cell resin foam with a skin with a sol solution which is a raw material of airgel under normal pressure or reduced pressure, and gelling the filled sol solution. It includes a gelling step of solification and a drying step of drying the wet gel. Each step will be described in detail below. The description of the airgel will be described in detail by taking silica aerogel, which is a preferable example, as an example. Further, as a method for producing the airgel composite material, steps other than the steps described below can be further included.

<< Foam formation process >>
The foam formation step will be described in detail below. As the open cell resin foam with a skin, a commercially available open cell resin foam with a skin can be used as long as the effect of the present invention is not impaired. Therefore, it is not always necessary to include the foam forming step in the method for producing the airgel composite material. In the following, a foam forming step when an olefin resin is used as a raw material, a foam forming step when a water-dispersible resin is used as a raw material, and foaming when a water-dispersible resin is not used as a raw material in a non-polyolefin foam. The method of each suitable example will be described in detail with respect to the body forming step.

<Foam form forming process when olefin resin is used as a raw material>
(material)
The olefin resin which is a raw material of the open cell resin foam with a skin is not particularly limited, and known ones can be used. Furthermore, other additives can be added as long as the effects of the present invention are not impaired. Hereinafter, an example of a method for producing a polyolefin foam will be described.

The polyolefin foam contains (A) (A1) polyolefin (excluding ethylene-propylene rubber), (A2) ethylene-propylene rubber and / or styrene-based thermoplastic elastomer, and (B) nonionic surfactant. It is obtained by impregnating the composition to be made with a substance which is a gas at normal temperature and pressure in a supercritical state under high temperature and high pressure, and then releasing the pressure to foam.

Examples of the polyolefin (A1) include polyethylene, polypropylene, polybutene-1, an ethylene-propylene copolymer, an ethylene-α-olefin copolymer, and a polymer blend of these. The polyethylene may be any of high density polyethylene, medium density polyethylene, linear low density polyethylene, low density polyethylene and the like, and polypropylene may be any of atactic, isotactic, syndiotactic, random and the like. Further, polypropylene having a high elongation viscosity such as polypropylene having a long chain branch in the main chain skeleton suitable for foaming or polypropylene containing a high molecular weight component and having a wide molecular weight distribution may be used. The copolymer may be a random copolymer or a block copolymer, and may be a thermoplastic resin or a thermoplastic elastomer. Of these, random polypropylene is preferable because heat resistance can be imparted to the obtained foam and the flexibility of the obtained foam can be maintained. The melt flow rate of the component (A1) is preferably 0.1 to 5 g / 10 min at 230 ° C. and 2.16 kgf, and more preferably 0.3 to 2 g / 10 min, because there is no gas release and foaming is easy. JIS K7210: 1999 compliant). The ethylene-propylene copolymer includes an ethylene-propylene copolymer (EPR) that is cured to become a rubber-like elastic body, but this is included in the component (A2) and is therefore excluded from (A1). As (A1), a resinous ethylene-propylene copolymer is included. In addition, other thermoplastic polymers may be present as long as the properties of the open-cell foam of the present embodiment are not impaired.

The ethylene-propylene rubber of (A2) is EPR (EPM), which is a copolymer of ethylene and propylene, which is cured to become a rubber-like elastic body; and a copolymer of ethylene, propylene and a small amount of non-conjugated diene. Certain EPDMs are included. Examples of the non-conjugated diene include ethylidene norbornene, dicyclopentadiene and 1,4-hexadiene, and in the present invention, any of them may be used.

The styrene-based thermoplastic elastomer (A2) may be a block copolymer in which styrene is bonded to one end or both ends of a polymer composed of hydrocarbon chains. For example, a block copolymer of styrene and butadiene, isoprene, isobutylene or the like may be used. , Or those block copolymers further hydrogenated, for example, styrene butadiene styrene block copolymer (SBS), styrene ethylene butylene styrene block copolymer (SEBS) hydrogenated with SBS, styrene isoprene styrene block copolymer (SIS). ), And SIS hydrogenated styrene ethylene propylene styrene block copolymer (SEPS), styrene isoprene butadiene isoprene styrene block copolymer, and hydrogenated styrene ethylene ethylene propylene styrene block copolymer (SEEPS), styrene vinyl isoprene styrene block copolymer, And its hydrogen additive, styrene isobutylene styrene block copolymer, styrene butadiene block copolymer, and its hydrogen additive, styrene isobutylene block copolymer, and its hydrogen additive, etc. may be used alone, but may be used in combination. You can also do it.

The average molecular weight of the component (A2) is preferably high. Further, it may be used by oil-expanding with process oil or the like. The component (A2) is used as it is without carrying out a crosslinking reaction.

(B) Nonionic surfactants include alkyl polyethers such as polyoxyethylene (polyoxypropylene) alkyl ethers, fatty acid polyether esters such as polyoxyethylene (polyoxypropylene) fatty acid esters, and dipolyoxyethylene. Alkyl polyether amines such as (dipolyoxypropylene) alkylamines, such as di (dioxyethylene) stearylamine, polyoxyethylene (polyoxypropylene) dialkylamines, polyoxyethylene (polyoxypropylene) alkylalkylene diamines, etc. Solbitan esters such as polyoxyethylene (polyoxypropylene) sorbitan ester and sorbitan alkyl ester, polyoxyethylene (polyoxypropylene) alkyl glyceryl ether, fatty acid (poly) glyceryl, for example monoglyceryl stearate, polyoxyethylene (polyoxy) Examples thereof include alkyl glyceryl polyethers or esters such as propylene) fatty acid glyceryl, alkanolamides such as fatty acid (di) ethanolamide, and mixtures thereof. The number of carbon atoms of the alkyl, fatty acid, and alkylene is preferably 10 or more from the viewpoint of compatibility with the polyolefin-based polymer composition, for example, C12 (such as lauryl or laurylate) and C18 (such as stearyl or stearate). , C22 (behenyl, behenilate, etc.) and the like. The number of repeating units of oxyalkyl such as polyoxyethylene and polyoxypropylene is preferably 1 to 20, and more preferably 10 or less. The number of repeating units of polyglyceryl is also preferably 1 to 20, and more preferably 10 or less. Further, one or a mixture selected from alkylpolyetheramine, fatty acid glyceryl, and fatty acid (di) ethanolamide can be preferably used, and higher alcohols such as stearyl alcohol may be added.

The component (A) used in this embodiment is (A1) polyolefin (excluding ethylene-propylene rubber) 50 to 95% by weight, preferably 60 to 90% by weight, more preferably 65 to 85% by weight, and ( A2) A polymer composition containing 5 to 50% by weight, preferably 10 to 40% by weight, more preferably 15 to 35% by weight of ethylene-propylene rubber and / or styrene-based thermoplastic elastomer. If the proportion of (A1) exceeds 95% by weight and the proportion of (A2) is less than 5% by weight, there is a problem that it is difficult to obtain sufficient flexibility of the foam and it is difficult to obtain a high foam. On the other hand, if the ratio of (A1) is less than 50% by weight and the ratio of (A2) exceeds 50% by weight, it is still difficult to obtain a high foam, and there is a problem that the shrinkage of the obtained foam becomes large.

The blending amount of the component (B) is required to be 0.2 to 10 parts by weight per 100 parts by weight of the polymer composition (A), preferably 0.3 to 5 parts by weight, and more preferably 0.5 to 3 parts by weight. It is a department. If the component (B) is less than 0.2 parts by weight, the required open-cell formation cannot be obtained, and only a foam having low air permeability can be obtained. On the other hand, if it exceeds 10 parts by weight, the foam breaks too much and the foam shrinks.

In the present invention, the components (A1), (A2), (B), and optionally the components to be optionally blended are mixed by a mixing means suitable for mixing the polymer material to prepare an effervescent composition. .. At this time, in order to give appropriate properties to the obtained foam as an optionally blended component, or to facilitate the production and processing of the foam, liquid paraffin is added to this foamable composition according to the purpose of use. Lubricates such as hydrocarbon-based process oils, higher fatty acid glycerin esters, higher fatty acid amides; wet silica, dry silica, talc, mica, diatomaceous earth, aluminum oxide, titanium oxide, zinc oxide, magnesium oxide, magnesium hydroxide, hydroxide. Aluminum, calcium hydroxide, potassium carbonate, calcium carbonate, magnesium carbonate, potassium sulfate, barium sulfate, glass beads, polytetrafluoroethylene, calcium tertiary phosphate, magnesium pyrophosphate, calcium stearate, zinc stearate, magnesium stearate, ethylene bis Bisamide compounds such as stearic acid amide, methylene bisstearic acid amide, nucleating agents such as stearic acid amide, 12-hydroxystearic acid amide, stearic acid triglyceride, stearic acid monoglyceride; Flame retardants such as aluminum hydroxide, magnesium hydroxide, antimony oxide, zinc carbonate, chlorinated paraffin, hexachlorocyclopentadiene; such as aromatic amines, benzoimidazoles, dithiocarbamates, phenolic compounds, stearic acid esters. Anti-aging agent; 2,6-di-t-butylphenol, 2,6-di-t-butyl-4-ethylphenol, 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 1, Antioxidants such as 1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane; conductive materials such as conductive carbon black, copper powder, nickel powder, tin oxide; carbon black , Organic pigments, dyes, colorants such as master batches containing them; and fillers such as silica, alumina, titanium oxide and the various additives mentioned above that have a filler function. can.

The substance that is gas at normal temperature and pressure to be impregnated with the effervescent composition in a supercritical state may be a substance that permeates the polymer in the effervescent composition in this supercritical state, and nitrogen, helium, or the like. Carbon dioxide, propane, butane, and mixed gases thereof are exemplified, and carbon dioxide and nitrogen are preferable, and carbon dioxide is particularly preferable because it is easy to handle, has high safety, and has an excellent working environment.

(Foam process)
Under the following conditions, a substance that is gaseous at normal temperature and pressure is impregnated into the polymer in the effervescent composition, and then the pressure is released to foam the polymer so as to form open cells. By reducing the pressure at a reduction rate of usually 10 to 30 MPa / s, foaming can be performed so as to form open cells. Since the open cell foam is directly obtained in the foaming step, there is no need for a step of breaking the closed cells by mechanical stress to form open cells in the subsequent step.

The temperature at which the foamable composition is impregnated with a substance that is gaseous at normal temperature and pressure is the temperature at which the substance is brought into a supercritical state because a functional foam can be efficiently obtained. It is particularly preferable that the temperature is 20 to 40 ° C. higher than the crystallization peak temperature of the polymer in the effervescent composition obtained by the measurement according to the above. Here, the supercritical state is a state showing a property intermediate between a gas state and a liquid state.

The impregnation pressure is preferably 8 to 15 MPa so that the impregnated substance that is a gas at normal temperature and pressure is brought into a supercritical state in order to completely impregnate and obtain fine cells. 10 to 15 MPa is more preferable in order to prevent gas from escaping.

The time for impregnating the effervescent composition with a substance that is gaseous at normal temperature and pressure varies depending on the required impregnation amount and the impregnation temperature / pressure, but is usually 3 to 30 minutes, preferably 5 to 20 minutes.

When the effervescent composition is foamed so as to form open cells, the foaming ratio is preferably 5 times or more. If it is less than 5 times, there arises a problem that excellent flexibility cannot be imparted to the obtained foam. The upper limit of the magnification is not particularly limited, but from the viewpoint of mechanical strength, it is 100 times or less, preferably 80 times or less, and more preferably 50 times or less.

A molded body of an open cell foam with a skin can be obtained by molding by extrusion molding together with foaming having a foaming ratio of 5 times or more. As the extruder, a single-screw tandem extruder may be used, and in some cases, it may be used in combination with a twin-screw extruder. By extrusion molding, it is possible to obtain an open cell foam with a skin in which the foam layer and the skin layer are integrated without going through an adhesion or fusion step. Since the bonding or fusion process is not performed, the thermal conductivity of the material used for sealing does not affect the heat insulating property, and the work efficiency does not decrease because the man-hours are not increased.

Extrusion molding will be described. The extrusion molding apparatus of the present invention includes an apparatus for melting a molding material containing a thermoplastic resin, an apparatus for mixing and mixing a gaseous material with the molding material to be melted at normal temperature and pressure in a supercritical state at the time of melting, and a normal temperature and normal temperature. It is provided with an extruder that heats and compresses the molten molding material in which a gaseous material is mixed by pressure and extrudes it from a die. The mixing and mixing device is installed so that a gaseous material is mixed into a socket provided in a barrel in the middle of the longitudinal direction of the extruder at normal temperature and pressure in a supercritical state.

That is, a polymer material melt-extruded by a screw is supplied with supercritical carbon dioxide from a socket and mixed to form a single-phase solution, and then the polymer material in which this single-phase solution is uniformly dispersed. A fluid flow is then extruded and foamed by passing it through a die at a high temperature in the form of a liquid mixture of a polymer material and very small bubbles while suppressing the growth of bubbles.

(Cut)
The obtained open cell resin foam with a skin can be processed into a predetermined size. Bubbles having an open cell structure are exposed on the cut surface. The sol solution is filled from the exposed bubbles.
By the above foam forming step, an open cell resin foam with an epidermis in which an epidermis layer having open cells is formed can be obtained.

<Foam formation step of non-polyolefin foam when water-dispersible resin is used as a raw material>
(material)
The open-cell resin foam with a skin contains an aqueous resin dispersion and an anionic surfactant as a foaming agent as raw materials. Furthermore, other additives can be added as long as the effects of the present invention are not impaired.

The water-dispersible resin used in the method for producing the resin foam is not particularly limited, and known ones can be used. The water-dispersible resin includes a stable-dispersible water-dispersible resin and an unstable-dispersible water-dispersible resin. In the present invention, the stable dispersion type water-dispersible resin is suitable because the polymer has high hydrophilicity and the airgel composite material can be efficiently produced without going through a vacuum step or the like.

The stable dispersion type water-dispersible resin refers to a water-dispersible resin having a precipitation rate (following the following method for a specific calculation method of the precipitation rate) of less than 10%, and has no structure or manufacturing method. Not limited. Further, the unstable dispersion type water-dispersible resin is an water-dispersible resin having a precipitation rate of 10% or more, and its structure and manufacturing method are not limited at all.

In order to evaluate the dispersion stability of the water-dispersible resin, a coagulant aqueous solution (0.5% by mass% calcium nitrate aqueous solution) is added to the water-dispersible resin, and the precipitation rate is calculated from the amount of precipitates produced. Can be done. The specific precipitation rate is obtained by the following formula (1). {In the formula (1), A is the dry mass (g) of the precipitate, B is the mass (g) of the water-dispersible resin, and C is the water dispersion. The solid content concentration (mass%) of the sex resin}.
Precipitation rate (%) = A / {B × (C / 100)} × 100 ... (1)

More specifically, 10 g of a water-dispersible resin is placed in a resin container having a capacity of 100 ml in a room at 23 ° C., and 10 g of an aqueous solution of calcium nitrate having a concentration of 0.5% by mass is added dropwise as an aqueous solution of a coagulant while stirring. After dropping the whole amount of the coagulant aqueous solution, let stand for 1 hour. Next, the entire amount is a glass filter (Sibata Scientific Technology Co., Ltd., suction filtration bottle 1L, Shibata Scientific Technology Co., Ltd., glass filter base for φ47 mm, Kiriyama Glass Co., Ltd., Kiriyama Separate 55Z) and 40 mesh filter (Yamani Co., Ltd.) Manufactured by T230LY-40) and filtered under reduced pressure to collect the precipitate. Further, the filtrate is washed with water until it becomes transparent, and then dried at 110 ° C. for 3 hours. The dry mass of the precipitate is measured, the precipitation rate is calculated based on the above formula (1), and the dispersion stability of the water-dispersible resin is evaluated from the precipitation rate. That is, a resin having a precipitation rate of less than 10% means that the resin particles are unlikely to aggregate, and is therefore evaluated as a "stable dispersion type water-dispersible resin". On the other hand, a resin having a precipitation rate of 10% or more means that the resin particles are likely to aggregate, and is therefore evaluated as an "unstable dispersion type water-dispersible resin".

The water-dispersible resin is not limited to one type of water-dispersible resin, and a plurality of types of water-dispersible resins may be used in combination. As described above, even when the water-dispersible resin is composed of a plurality of water-dispersible resins, the precipitation rate is calculated for the entire water-dispersible resin, and whether the water-dispersible resin is a stable dispersion type or an unstable dispersion type. To determine.

Hereinafter, a stable dispersion type water-dispersible resin, which is a preferable example, will be described.
The stable dispersion type water-dispersible resin is not particularly limited, and examples thereof include urethane emulsions, acrylic emulsions, vinyl acetate emulsions, vinyl chloride emulsions, and epoxy emulsions. Of these, particularly suitable urethane emulsions and acrylic emulsions will be described in detail. It should be noted that the use of urethane emulsion is suitable because the obtained urethane resin foam has excellent flexibility and low compression residual strain. In addition, it is also preferable to use an acrylic emulsion because it has excellent strength, light weight, and heat insulation.

Examples of the method for producing the aqueous dispersion (urethane emulsion) of the urethane resin include the following methods (I) to (III).

(I) Neutralize, if necessary, with an organic solvent solution or organic solvent dispersion of a urethane resin having a hydrophilic group obtained by reacting an active hydrogen-containing compound, a compound having a hydrophilic group, and polyisocyanate. A method of obtaining an aqueous dispersion of urethane resin by mixing an aqueous solution containing an agent.

(II) Whether to mix an active hydrogen-containing compound, a compound having a hydrophilic group, and a terminal isocyanate group-containing urethane prepolymer having a hydrophilic group obtained by reacting polyisocyanate with an aqueous solution containing a neutralizing agent. Alternatively, a method in which a neutralizing agent is added to a prepolymer in advance, water is mixed and dispersed in water, and then reacted with a polyamine to obtain a urethane resin aqueous dispersion.

(III) An active hydrogen-containing compound, a compound having a hydrophilic group, and a terminal isocyanate group-containing urethane prepolymer having a hydrophilic group obtained by reacting polyisocyanate are mixed with an aqueous solution containing a neutralizing agent and a polyamine. Or, after adding a neutralizing agent to the prepolymer in advance, an aqueous solution containing a polyamine is added and mixed to obtain a urethane resin aqueous dispersion.

Examples of the polyisocyanate used in the production of the urethane resin include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylenedi isocyanate, p-fphenylenedi isocyanate, 4,4'-diphenylmethane diisocyanate, and 2,4. '-Diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-biphenylenediisocyanate, 3,3'-dimethoxy-4,4'-biphenylenediocyanate, 3,3'-dichloro- 4,4'-biphenylenediocyanate, 1,5-naphthalenediocyanate, 1,5-tetrahydronaphthalenediisocyanate, tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclohexylene Diisocyanate, 1,4-cyclohexamethylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 3,3'-dimethyl-4, Examples thereof include 4'-dicyclohexylmethane diisocyanate. Further, a polyisocyanate having a valence of 3 or more may be used in combination as long as the effect of the invention is not impaired.

Examples of the compound having a hydrophilic group include polyester polyols, polyether polyols, polycarbonate polyols, polyacetal polyols, polyacrylate polyols, polyesteramide polyols, polythioether polyols, and polyolefin polyols such as polybutadienes. Two or more of these high molecular weight compounds may be used in combination. As the polyester polyol, known ones may be used.

In the above methods (I) to (III), an emulsifier may be further used as long as the effects of the invention are not impaired. Examples of such emulsifiers include nonionic emulsifiers such as polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene styrene phenyl ether, and polyoxyethylene sorbitol tetraoleate; fatty acid salts such as sodium oleate, and alkyl. Anionic emulsifiers such as sulfate ester salts, alkylbenzene sulfonates, alkyl sulfosuccinates, naphthalene sulfonates, alkane sulfonate sodium salts, alkyl diphenyl ether sulfonate sodium salts; polyoxyethylene alkyl sulfates, polyoxyethylene alkylphenyl sulfates Nonion anionic emulsifiers such as;

As a method for producing an aqueous dispersion (acrylic emulsion) of an acrylic resin, a (meth) acrylic acid ester-based monomer is an essential polymerizable single amount in the presence of a polymerization initiator, an emulsifier and a dispersion stabilizer if necessary. It can be obtained by using it as a body component and, if necessary, copolymerizing a mixture of other polymerizable monomers copolymerizable with these monomers.

Examples of the polymerizable monomer that can be used in the production of the acrylic resin emulsion include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and (meth). ) Hexyl acrylate, (meth) heptyl acrylate, octyl (meth) acrylate, octadecyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cyclohexyl (meth) acrylate, nonyl (meth) acrylate, (meth) (Meta) acrylates such as dodecyl acrylate, stearyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate, etc. Ester-based monomers; acrylic acid, methacrylic acid, β-carboxyethyl (meth) acrylate, 2- (meth) acryloyl propionic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, itaconic acid half ester, maleic acid half Unsaturated bond-containing monomer having a carboxyl group such as ester, maleic anhydride, itaconic anhydride; glycidyl group-containing polymerizable monomer such as glycidyl (meth) acrylate and allyl glycidyl ether; 2-hydroxyethyl (meth) Hydroxyl group-containing polymerizable monomers such as acrylate, 2-hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, and glycerol mono (meth) acrylate; ethylene glycol di (meth) acrylate, 1,6-hexanediol di. (Meta) Acrylate, Neopentyl Glycol Di (Meta) Acrylate, Trimethylol Propanetri (Meta) Acrylate, Polyethylene Glycol Di (Meta) Acrylate, Polypropylene Glycol Di (Meta) Acrylate, Dialyl Falate, Divinyl benzene, Allyl (Meta) Acrylate , Etc. can be mentioned.

When an emulsifier is used in the production of the acrylic emulsion, the above-mentioned emulsifier or the like may be used.

The unstable dispersion type water-dispersible resin is not particularly limited, and examples thereof include rubber latex. Rubber latex is suitable because the foam feels good and has excellent elasticity. Next, the rubber latex will be described in detail.

The aqueous dispersion of rubber (rubber latex) may be a natural rubber latex or a synthetic rubber latex. The synthetic rubber latex can be produced by emulsion polymerization of an aliphatic conjugated diene-based monomer and another copolymerizable monomer. Here, examples of the aliphatic conjugated diene-based monomer include 1,2-butadiene, 1,3-butadiene, isoprene, and chloroprene.

Other copolymerizable monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, ( (Meta) acrylic acid ester-based monomers such as heptyl (meth) acrylic acid, octyl (meth) acrylic acid, octadecyl (meth) acrylic acid; (meth) acrylic acid, crotonic acid, maleic acid and its anhydrides, fumaric acid , Unsaturated dicarboxylic acid monoalkyl esters (eg monomethyl maleate, monoethyl fumarate, mononormal butyl itaconate) and other unsaturated bond-containing monomers; styrene, α-methylstyrene, vinyltoluene , Chlorstyrene, 2,4-dibromostyrene and other ethylenically unsaturated aromatic monomers; Acrylonitrile, Metacronitrile and other unsaturated nitriles; Vinyl acetate, vinyl propionate and other vinyl esters; Vinylidene halide; hydroxyalkyl esters of ethylenically unsaturated carboxylic acids such as -2-hydroxyethyl (meth) acrylate; -2-hydroxypropyl (meth) acrylate; ethylenically unsaturated such as glycidyl (meth) acrylate. Glycidyl esters of carboxylic acids; (meth) acrylamide, N-methylol (meth) acrylamide, butoxymethyl (meth) acrylamide, diacetone acrylicmid; and the like.

A rubber latex (synthetic rubber latex) that can be used as an water-dispersible resin can be obtained by emulsion polymerization of the above-mentioned monomer in an aqueous medium in the presence of an emulsifier, a free radical generation catalyst, or the like. At this time, a two-stage polymerization method can also be adopted. As the emulsifier, various anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants and the like can be used.

The dispersion medium of the aqueous liquid medium contains water as an essential component, but may be a mixture of water and a water-soluble solvent. The water-soluble solvent is, for example, alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, ethyl carbitol, ethyl cellosolve, butyl cellosolve, polar solvents such as N-methylpyrrolidone, and one or more of these. A mixture of the above may be used.

The amount of the water-dispersible resin (solid content) to be blended with respect to the dispersion medium is preferably 30 to 70 parts by mass with respect to 100 parts by mass of the dispersion medium. Within such a range, an effect that a stable foam can be molded can be obtained.

The anionic surfactant (foaming anionic surfactant) functions as a foaming agent for an aqueous liquid medium.

Specific examples of anionic surfactants include sodium laurate, sodium myristate, sodium stearate, ammonium stearate, sodium oleate, potassium oleate soap, potassium castor oil soap, potassium palm oil soap, sodium lauroyl sarcosin, and the like. Sodium myristyl sarcosin, sodium oleyl sarcosin, sodium cocoyl sarcosin, sodium coconut oil alcohol sulfate, sodium polyoxyethylene lauryl ether sulfate, sodium alkyl sulfosuccinate, sodium lauryl sulfoacetate, sodium dodecylbenzene sulfonate, sodium α-olefin sulfonate, Etc., but sodium alkylsulfosuccinate is particularly preferable.

Here, the anionic surfactant preferably has an HLB of 10 or more, more preferably 20 or more, and more preferably 30 or more, in order to facilitate dispersion in an aqueous liquid medium. Especially suitable.

The HLB value means a hydrophilic-hydrophobic balance (HLB) value, and is obtained by the Oda method. For the method of obtaining the HLB value by the Oda method, see "Introduction to New Surfactants", pp. 195-196 and March 20, 1957, published by Maki Shoten, by Ryohei Oda, "Synthesis and Application of Surfactants", No. 492. It is described on page 502, and can be determined by HLB value = (inorganic / organic) × 10.

The anionic surfactant can be 1 to 10 parts by mass when the resin solid content contained in the aqueous dispersion is 100 parts by mass.

As other additives, a metal cation source, a gelling agent, a surfactant (emulsifier) for dispersing an aqueous dispersible resin, a curing agent, a water-soluble polymer and the like may be added.

A metal cation source is a component capable of releasing a metal cation into water that can combine with an anionic surfactant to form a water-insoluble salt. The presence of such a component in the system binds to the anionic surfactant to form a water-insoluble salt. As a result, by imparting thixotropy to the foam raw material mixture mixed with the gas and lowering the fluidity, it is possible to suppress the coalescence of bubbles even during heating.

Such a metal cation source is not particularly limited as long as it is a component that dissolves in water to generate metal ions, and is a metal salt such as an inorganic metal salt or an organic metal salt, for example, calcium nitrate; alkali, for example, water. Calcium oxide and calcium oxide; metal alone, for example, calcium. Of these, metal salts are preferable because they have a relatively large ionization constant in water.

Examples of the components include alkali metal ions such as lithium ion, sodium ion and potassium ion, aluminum ion, barium ion, calcium ion, copper ion, iron ion, magnesium ion, manganese ion, nickel ion, tin ion and titanium ion. Polyvalent metal ions such as zinc ions, inorganic acids (eg, hydrochloric acid, odorous acid, hydroiodic acid, sulfuric acid, nitrate, phosphoric acid, thiocyanic acid, etc.), and organic acids (eg, acetic acid, oxalic acid, lactic acid, etc.) Examples thereof include organic carboxylic acids such as fumaric acid, fumaric acid, citric acid, salicylic acid and benzoic acid, and salts with organic sulfonic acid) and the like.

Specific examples include lithium chloride, sodium chloride, potassium chloride, sodium bromide, potassium bromide, sodium iodide, potassium iodide, sodium sulfate, potassium nitrate, sodium acetate, potassium oxalate, sodium citrate, potassium benzoate and the like. Salts of alkali metals, aluminum chloride, aluminum bromide, aluminum sulfate, aluminum nitrate, sodium aluminum sulfate, potassium aluminum sulfate, aluminum acetate, barium chloride, barium bromide, barium iodide, barium oxide, barium nitrate, thiocyan Barium acid, calcium chloride, calcium bromide, calcium iodide, calcium nitrite, calcium nitrate, calcium dihydrogen phosphate, calcium thiocyanate, calcium benzoate, calcium acetate, calcium salicylate, calcium tartrate, calcium lactate, calcium fumarate , Calcium citrate, copper chloride, copper bromide, copper sulfate, copper nitrate, copper acetate, iron chloride, iron bromide, iron iodide, iron sulfate, iron nitrate, iron oxalate, iron lactate, iron fumarate, citric acid Iron, magnesium chloride, magnesium bromide, magnesium iodide, magnesium sulfate, magnesium nitrate, magnesium acetate, magnesium lactate, manganese chloride, manganese sulfate, manganese nitrate, manganese dihydrogen phosphate, manganese acetate, manganese salicylate, manganese benzoate, Polyvalent metals such as manganese lactate, nickel chloride, nickel bromide, nickel sulfate, nickel nitrate, nickel acetate, tin sulfate, titanium chloride, zinc chloride, zinc bromide, zinc sulfate, zinc nitrate, zinc thiocyanate, zinc acetate, etc. Kind of salt and the like.

In a system in which a stable dispersion type water-dispersible resin exists, the solubility is 10 g / g because the gelation strength is strong and the gelation time is short, even though the component that becomes the metal cation source of the metal cation is a water-soluble metal salt. It is preferably 100 g / 100 g water or more, more preferably 30 g / 100 g water or more, and particularly preferably 100 g / 100 g water or more. Examples of the electrolyte as such a component include calcium nitrate (solubility 138 g / 100 g water), aluminum sulfate (solubility 38.6 g / 100 g water), magnesium sulfate (solubility 36.3 g / 100 g water), and the like. ..

In a system in which an unstable dispersion type water-dispersible resin exists, even if the component that becomes the metal cation source of the metal cation is a poorly water-soluble metal salt, foreign substances such as agglomerates are unlikely to be generated, so the solubility is 10 g / 100 g. Less than water is preferred, less than 3 g / 100 g water is more preferred, and less than 1 g / 100 g water is particularly preferred. The lower limit is not particularly limited, but is 0.0001 g / 100 g of water or more. Examples of the electrolyte as such a component include calcium citrate (solubility 25.9 mg / 100 g water), calcium carbonate (solubility 0.81 g / 100 g water), and primary calcium phosphate (solubility 1.8 g / 100 g water). And so on.

When an anionic surfactant is insolubilized with a metal cation (metal cation source) and an electrolyte is used as the metal cation source, the amount of the electrolyte blended is the water-dispersible resin (in the mixture of the water-dispersible resin). Solid content) 1.0 to 10 parts by mass is preferable with respect to 100 parts by mass, and 2 to 5 parts by mass is more preferable. Within such a range, the gelation strength and gelation time are appropriate, so that an effect that a fine cell structure can be formed can be obtained.

When insolubilizing an anionic surfactant with a metal cation (metal cation source), the valence of the metal cation, which is the target component to be insolubilized, / the target component to be insolubilized in the mixture of the water-dispersible resin. The valence of the anionic surfactant is preferably 0.1 or more, more preferably 0.5 or more, and particularly preferably 1.0 or more, which is the molar equivalent of the valence. Within such a range, the gelation strength and gelation time are appropriate, so that an effect that a fine cell structure can be formed can be obtained.

The gelling agent lowers the chemical stability of the polymer particles existing in the emulsion state, that is, in the emulsion state in the emulsion composition, and agglomerates the particles to form a so-called gelled state. It is a substance of.

Such a gelling agent may be appropriately added depending on the gelation method, for example, hexafluorosilates such as sodium silicate, potassium silicate, calcium silicate; or acetate of cyclohexylamine. Cyclohexylamine salts such as sulfamate can be used, and generally, a liquid product obtained by converting these compounds into an aqueous solution is used. For example, by using sodium silicate, reaction control such as control of gelation start time becomes easy.

When the gelling agent is blended, the blending amount is not particularly limited, but is preferably about 1 to 10 parts by mass with respect to 100 parts by mass of the solid content of the water-dispersible resin in the mixture of the water-dispersible resin. .. If the blending amount of the gelling agent is out of the above range, suitable gelation cannot be exhibited, that is, gelation does not occur in a liquid state even after a long period of time, or gelation progresses in a short time to obtain a desired shape. It becomes difficult to mold. As a result, specifically, the time required to complete the gelation (gelation time) becomes too long or too short, so that a suitable resin foam cannot be obtained.

The present water-dispersible resin-dispersing surfactant is a surfactant for dispersing the water-dispersible resin (unlike an anionic surfactant, it does not have to have an effect as a foaming agent). Such a surfactant may be appropriately selected depending on the water-dispersible resin to be selected. For example, when the water-dispersible resin is a urethane emulsion, an acrylic emulsion, or a rubber latex, the specific surfactant for dispersing the water-dispersible resin is as described above.

The curing agent is a cross-linking agent for water-dispersible resins, and a required amount may be added depending on the intended use. Examples of the cross-linking method using a curing agent include physical cross-linking, ionic cross-linking, and chemical cross-linking, and the cross-linking method can be selected according to the type of the water-dispersible resin.

As the curing agent, an epoxy-based curing agent, a melamine-based curing agent, an isocyanate-based curing agent, a carbodiimide-based curing agent, an oxazoline-based curing agent, etc. are used depending on the type and amount of functional groups contained in the resin compounding system used. An appropriate amount can be used depending on the situation.

When rubber latex is used as the water-dispersible resin, a cross-linking agent (an additive for cross-linking rubber polymers, for example, a vulcanizing agent) and a cross-linking accelerator (cross-linking agent) commonly used in the production of resin foams are used. It is an additive for accelerating the cross-linking reaction by the cross-linking agent, and for example, a vulcanization accelerator) may be added.

As the cross-linking agent, sulfur, an organic peroxide, a phenol compound, or the like is used depending on the type of rubber polymer and the cross-linking reaction mechanism. In the case of cross-linking with sulfur, in addition to colloidal sulfur and fine powdered sulfur, sulfur compounds such as sulfur dichloride and dipentamethylene thiuram tetrasulfide can be used. In the case of cross-linking with an organic peroxide, hydroperoxides such as t-butyl hydroperoxide and cumene hydroperoxide; acyl peroxides such as benzoyl peroxide and m-toluyl peroxide; t-butyl cumyl peroxide, dicumyl peroxide, 2,5- Alkyl peroxides such as dimethyl-2,5-bis (t-butoxyperoxy) hexane; peroxyesters such as t-butoxyperoxy-3,3,5-trimethylcyclohexanoate, t-butoxyperoxybenzoate; 1,1- Peroxy ketals such as bis (t-butoxyperoxy) cyclohexane, 1,1-bis (t-butoxyperoxy) -3,3,5-trimethylcyclohexa; t-butoxyperoxyisopropylcarbonate, t-butoxyperoxy-2- Organic peroxides such as peroxycarbonate such as ethylhexyl carbonate can be used. The organic peroxide may be blended as it is, and is stable by being adsorbed on an inorganic powder such as molecular sieve, dissolved in a hydrocarbon or a plasticizer, or miscible with an inert liquid such as polydimethylsiloxane. The modified product may be used in the formulation. In the case of cross-linking with a phenol compound, an archiphenol / formaldehyde resin, a sulfurized-p-tertiary butylphenol resin, an alkylphenol / sulfide resin and the like can be used. The amount of the cross-linking agent to be blended varies depending on the type of rubber polymer, the cross-linking mechanism, and the cross-linking agent, but is preferably 0.02 to 20 parts by mass with respect to 100 parts by mass of the rubber latex in the mixture of rubber latex. More preferably, 1 to 10 parts by mass.

Although various substances can be used as the cross-linking accelerator, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc di-n-butyldithiocarbamate, zinc dibenzyldithiocarbamate, and ethylphenyl are used because they reduce the swelling property to polar oils. Zinc dithiocarbamate such as zinc dithiocarbamate, zinc N-pentamethylene dithiocarbamate; tetramethylthiuram monosulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, N, N'-dimethyl-N, N' Thiurams such as −diphenylthium disulfide, dipentamethylene thiuram tetrasulfide; N, N-diisopropyl-2-benzothiarylsulfenamide, N-t-butyl-2-benzothiarylsulfenamide, N-cyclohexyl-2 Sulfenamides such as -benzothiazyl sulfenamide, N, N-dicyclohexyl-2-benzothiazyl sulfenamide, N-oxydiethylene-2-benzothiazyl sulfenamide; 2-mercaptobenzothiazole and The salts (sodium salt, zinc salt, cyclohexylamine salt, dicyclohexylamine salt, etc.), 2- (4'-morpholinodithio) benzothiazole, 4-morpholinyl-2-benzothiazyl disulfide, 2- (N, N-diethyl). Bentothiazoles such as thiocarbamoylthio) benzothiazole; as well as mixtures thereof are preferred. Of these, zinc dithiocarbamate is more preferable, and zinc dibutyldithiocarbamate is particularly preferable. The amount of the cross-linking accelerator to be blended is preferably 0.02 to 20 parts by mass, more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the rubber polymer in the mixture of rubber latex.

Regarding the cross-linking agent, the cross-linking accelerator, and the anti-aging agent, in order to improve the dispersibility in the rubber latex, these auxiliary raw materials are previously dispersed in water using a dispersant or the like to form a paste. (Vulcanization paste) may be prepared and this vulcanization paste may be added to the rubber latex.

When rubber latex is used as the water-dispersible resin, a defoaming inhibitor commonly used in the production of resin foams may be added. For example, a reaction product obtained by reacting an alkyl chloride such as ethyl chloride with formaldehyde and ammonia, for example, an ethyl chloride-formaldehyde-ammonia reaction product; an alkyl quaternary ammonium chloride; an alkylaryl sulfonate; and a higher fatty acid. Ammonia, for example, polyethyleneimine and / or a polyethyleneimine derivative, etc. are exemplified. Of these, reaction products of alkyl chloride, formaldehyde, and ammonia are more preferable because they have an excellent bubble stabilizing effect.

The blending amount of the foam rupture inhibitor is preferably 0.1 to 0.9 parts by mass, more preferably 0.3 to 0.6 parts by mass, based on 100 parts by mass of the solid content in the rubber latex composition.

The water-soluble polymer is a polymer having a solubility of 1 g / 100 g or more in water. In order to increase the hydrophilicity of the open cell resin foam with a skin and facilitate the penetration of the sol solution into the resin foam, it is preferable to add a water-soluble polymer to the aqueous liquid medium to form the resin foam. The water-soluble polymer is not particularly limited as long as it does not inhibit the effect of the present invention, and is not particularly limited, and is a -COOM group or a -SO ₃ M group (M is a hydrogen atom, a group I, II, III element of the periodic table, amine, ammonium. ), -NH ₂ , -OH and other polymers with hydrophilic groups can be exemplified. As the water-soluble polymer, a sulfonyl group-containing polymer and a carboxyl group-containing polymer are preferable. A sulfonyl group-containing polymer is more preferable because a high acid dissociation constant increases the difference in ion concentration and high water absorption can be expected. Further, the water-soluble polymer is more preferably a copolymer of a sulfonyl group-containing polymer and a carboxyl group-containing polymer.

Specific examples include -COOM group or -SO ₃ M group-containing polyurethane, -COOM group or -SO ₃ M group-containing polyurethane, -COOM group or -SO ₃ M group-containing polyester, -COOM group or -SO ₃ M group-containing Epoxy compounds, -COOM group or -SO ₃ M group containing polyamic acid, -COOM group or -SO ₃ M group containing acrylonitrile-butadiene copolymer, -COOM group or -SO ₃ M group containing styrene-butadiene copolymer, -COOM group or -SO ₃ M group-containing polybutadiene, polyacrylamide, sodium polyacrylate, polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), hydroxyethyl cellulose (MRC), methyl cellulose (MC), polyethylene oxide, polyethylene imine, and derivatives thereof, etc. Can be used, but is not limited to these.

In order to exhibit high hydrophilicity, the water-soluble polymer preferably has a solubility of 1 g / 100 g water or more, and more preferably 10 g / 100 g water or more. The upper limit value is not particularly limited, but is, for example, 500 g / 100 g of water or less. The weight average molecular weight of the water-soluble polymer is preferably 500 or more and 1,000,000 or less, more preferably 1,000 or more and 100,000 or less, further preferably 1,000 or more and 10000 or less, and particularly preferably 3000 or more and 5000 or less. The water-soluble polymer is preferably 1 to 15 parts by mass, more preferably 3 to 8 parts by mass, when the solid content of the resin contained in the aqueous dispersion is 100 parts by mass. Within such a range, high hydrophilicity is exhibited and an increase in liquid viscosity during foaming can be suppressed.

Liquid paraffins and hydrocarbons are added to this aqueous resin dispersion depending on the purpose of use, in order to give appropriate properties to the obtained foam as an optional compound, or to facilitate the production and processing of the foam. Lubricants such as system process oils, higher fatty acid glycerin esters, higher fatty acid amides; phosphate esters, melamine phosphate or piperazine phosphate, aluminum hydroxide, magnesium hydroxide, antimony oxide, zinc carbonate, chlorinated paraffin, hexachlorocyclopentadiene. Flame retardants such as; anti-aging agents such as aromatic amines, benzoimidazoles, dithiocarbamates, phenol compounds, phosphite esters; 2,6-di-t-butylphenol, 2,6-di- t-Butyl-4-ethylphenol, 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) Antioxidants such as butane; conductive materials such as conductive carbon black, copper powder, nickel powder, tin oxide; carbon blacks, organic pigments, dyes, colorants such as master batches containing them; and silica, Alumina, titanium oxide, and other fillers such as those having a filler function among the above-mentioned various additives can be blended.

(Preparation of raw materials)
In the raw material preparation, an aqueous liquid medium which is a raw material mixture of the open cell resin foam with a skin is prepared by mixing each of the raw materials as described above. The mixing method at this time is not particularly limited, but for example, it may be mixed while stirring in a container such as a mixing tank in which each component is mixed.

(Stirring, foaming process)
In the stirring and foaming steps, a predetermined foaming gas is added to the water-based liquid medium obtained in the raw material preparation step, and these are sufficiently mixed to allow a large number of bubbles to exist in the water-based liquid medium (foaming water-based liquid medium). ). This stirring and foaming step is usually carried out by sufficiently mixing the raw material mixture of the liquid resin foam obtained in the raw material preparation step with the foaming gas by a mixing device such as a mixing head.

The foaming gas mixed with the aqueous liquid medium in the stirring and foaming steps forms bubbles (cells) in the resin foam, and the foaming ratio of the obtained resin foam is determined by the amount of the foaming gas mixed. And the apparent density is determined.

In order to adjust the apparent density of the resin foam, the desired apparent density of the resin foam and the volume of the raw material of the resin foam (for example, the internal volume of the mold into which the raw material of the resin foam is injected). Therefore, the required weight of the raw material of the resin foam may be calculated, and the amount of the foaming gas may be determined so as to have a desired volume at this weight. Air is mainly used as the type of gas for foaming, but other inert gases such as nitrogen, carbon dioxide, helium, and argon can also be used.

The foaming method used in the method for producing a resin foam according to this embodiment is not particularly limited as long as it is a method generally used in the production of foam, but for example, a mechanical floss (mechanical foaming) method is used. can do.

The mechanical floss method is a method in which air in the atmosphere is mixed with the water-based liquid medium and foamed by stirring the water-based liquid medium with a stirring blade or the like. As the stirring device, a stirring device generally used in the mechanical floss method can be used without particular limitation, and for example, a homogenizer, a dissolver, a mechanical floss foaming machine, or the like can be used. According to this mechanical floss method, a resin foam having an apparent density suitable for various uses can be obtained by adjusting the mixing ratio of the aqueous liquid medium and air.

The mixing time of the aqueous liquid medium and air is not particularly limited, but is usually 1 to 10 minutes, preferably 2 to 6 minutes. The mixing temperature is not particularly limited, but is usually room temperature. The stirring speed in the above mixing is preferably 200 rpm or more (more preferably 500 rpm or more) in order to make the bubbles finer, and preferably 2000 rpm or less (800 rpm or less is preferable) in order to smooth the discharge of the foam from the foaming machine. More preferable).

(Molding)
The water-based liquid medium foamed as described above (foamed water-based liquid medium) is formed into a sheet shape or the like suitable for the desired thickness of the resin foam by a known means such as a doctor knife or a doctor roll.

(Heating process)
The heating step evaporates the dispersion medium in the molded water-based liquid medium. The drying method at this time is not particularly limited, but for example, hot air drying or the like may be used. The drying temperature and drying time are not particularly limited, but may be, for example, about 1 to 3 hours at about 80 ° C.

Further, in this heating step, the dispersion medium evaporates from the foaming water-based liquid medium, and the path when the vapor escapes is communicated from the inside to the outside of the resin foam. Therefore, in the resin foam according to the present embodiment, the path through which the water vapor escapes remains as open cells, so that at least a part of the bubbles existing in the resin foam becomes open cells. Here, if the effervescent gas mixed in the stirring and foaming steps remains as it is, it becomes closed cells in the obtained resin foam, and the mixed effervescent gas releases steam in this step. When they are communicated with each other, they become open cells in the obtained resin foam. Further, in the present embodiment, some of the bubbles in the resin foam may be open cells, and the remaining bubbles may be closed cells, or all the bubbles may be open cells.

When a curing agent is added, the heating step proceeds and completes the curing (crosslinking) reaction of the raw material. Specifically, the raw materials are crosslinked with each other by the above-mentioned curing agent to form a cured resin foam. The heating means at this time is not particularly limited as long as the raw material can be sufficiently heated to cure (crosslink) the raw material, and for example, a tunnel type heating furnace or the like can be used. Further, the heating temperature and heating time may be any temperature and time that can cure (crosslink) the raw material, and may be, for example, about 1 hour at 80 to 150 ° C. (particularly about 120 ° C.). ..

FIG. 1 is a photograph of a cross section perpendicular to the surface of the epidermis layer. As shown in FIG. 1, an epidermis layer containing open cells is formed on the surface of the foam layer having open cells. In the foam forming step, the foamed water-based liquid medium (foamed water-based liquid medium) was supplied onto the PET sheet, and was adjusted to the desired thickness of the resin foam by, for example, a known means such as a doctor knife and a doctor roll. By being molded into a sheet shape or the like, the surface of the foam layer in contact with the PET sheet die is altered to form a skin layer. FIG. 2 shows a photograph of the surface of the epidermis layer observed from the normal direction of the surface of the epidermis layer. According to FIG. 2, it can be understood that the open cells have reached the surface of the epidermis layer.

Some of the open cells contained in the epidermis layer reach the surface of the epidermis layer and permeate the outside air. Therefore, in the sol solution filling step described later, the sol solution can be filled inside the foam through the open cells under normal pressure.

(Cut)
The obtained open cell resin foam with a skin can be processed into a predetermined size. Bubbles having an open cell structure are exposed on the cut surface. The sol solution is filled from the exposed bubbles.
By the above foam forming step, an open cell resin foam with an epidermis in which an epidermis layer having open cells is formed can be obtained.

<Foam formation process of non-polyolefin foam when water-dispersible resin is not used as a raw material>
(material)
The material of the foam according to the present embodiment is not particularly limited, but silicone resin and silicone rubber are suitable from the viewpoint of flame retardancy and heat resistance.

An example of a foam forming step using a silicone resin or a silicone rubber will be described below.

The raw material for the silicone resin foam is not particularly limited, but a silicone resin that foams with hydrogen gas generated by the reaction of the contained components can be used as the raw material.

Examples of the raw material that can be foamed by this hydrogen gas include a self-foaming reaction type liquid silicone resin. In the case of this liquid silicone resin, a reaction is carried out by mixing two liquids of a main agent and a curing agent and stirring them. Is started, the reaction proceeds in a short time, and the silicone resin foam can be efficiently formed.

As the raw material for the silicone resin foam, the main component of the raw material composition is a siloxane compound having an alkenyl group, and the curing agent is a siloxane compound having a Si—H group. Hydrogen gas is generated by the addition reaction of these siloxane compounds, and a silicone resin foam is formed.

Examples of the alkenyl group include a vinyl group, an allyl group, a butenyl group, a petenyl group, a hexenyl group and the like, and a vinyl group is preferable.

In order to increase the efficiency of mixing and stirring the two liquids, other additives such as a foaming agent, a surfactant, a viscosity modifier, an emulsifier, and a diluent can be used as needed.

Further, in the reaction, transition metals of Groups 8 to 10 in the periodic table and their complexes can be used as catalysts, and platinum compounds are suitable. The reaction is promoted by these catalysts, and the silicone resin foam can be formed more efficiently.

Further, the raw materials for the silicone resin foam include reaction control agents such as unsaturated alcohols for controlling the addition reaction, nitrogen-containing compounds and phosphorus compounds, and silica and alumina for improving the physical properties of the silicone resin foam. Various additives such as a filler such as aluminum hydroxide can also be blended.

(Preparation of raw materials)
By mixing each of the raw materials as described above, a raw material mixture of the open cell resin foam with a skin is prepared. The mixing method at this time is not particularly limited, but for example, it may be mixed while stirring in a container such as a mixing tank in which each component is mixed.

The blending amount of the main agent and the curing agent is not particularly limited and can be determined according to the physical property value of the foam. For example, the blending ratio of the main agent and the curing agent is set to 100: 0.1 to 100 :. It can be 50, preferably 100: 1 to 100:30, more preferably 100: 5 to 100:20.

(Stirring, foaming process)
The stirring and foaming steps are carried out by sufficiently mixing the raw material mixture of the liquid resin foam obtained in the raw material preparation step with a mixing device such as a mixing head.

(Molding)
The raw material mixture of the resin foam foamed as described above is formed into a sheet shape or the like suitable for the desired thickness of the resin foam by a known means such as a doctor knife or a doctor roll.

(Heating process)
In the heating step, the curing (crosslinking) reaction of the raw material is advanced and completed. The silicone foam raw material can be reacted at room temperature (for example, 20 to 30 ° C.), but it is preferable to heat it to accelerate the reaction. Specifically, the raw materials are crosslinked with each other by the above-mentioned curing agent to form a cured resin foam. The heating means at this time is not particularly limited as long as the raw material can be sufficiently heated to cure (crosslink) the raw material, and for example, a tunnel type heating furnace or the like can be used. Further, the heating temperature and heating time may be any temperature and time as long as the raw material can be cured (crosslinked), for example, 30 to 200 ° C., preferably 30 to 170 ° C., and heating. The time may be about one hour. The heating rate is preferably gradually increased from room temperature, and the reaction temperature can be controlled in a wide temperature range.

Further, in this foaming step / heating step, the path through which the generated hydrogen passes through the resin foam raw material is communicated from the inside to the outside of the resin foam. Therefore, in the resin foam according to the present embodiment, since the path when the hydrogen escapes remains as open cells, at least a part of the bubbles existing in the resin foam becomes open cells.

Here, if the effervescent gas mixed in the stirring and foaming steps remains as it is, it becomes closed cells in the obtained resin foam, and the mixed effervescent gas releases steam in this step. When they are communicated with each other, they become open cells in the obtained resin foam. Further, in the present embodiment, some of the bubbles in the resin foam may be open cells, and the remaining bubbles may be closed cells, or all the bubbles may be open cells.

Also in this embodiment, an epidermis layer containing open cells is formed on the surface of the foam layer having open cells as shown in FIG. In the foam forming step, the foamed water-based liquid medium (foamed water-based liquid medium) was supplied onto the PET sheet, and was adjusted to the desired thickness of the resin foam by, for example, a known means such as a doctor knife and a doctor roll. By being molded into a sheet shape or the like, the surface of the foam layer in contact with the PET sheet die is altered to form a skin layer. As shown in FIG. 2, it can be understood that the open cells have reached the surface of the epidermis layer.

Some of the open cells contained in the epidermis layer reach the surface of the epidermis layer and permeate the outside air. In particular, when the air permeability of the open cell resin foam is 10 cm ³ / cm ² / sec or more, the sol solution is filled inside the foam through the open cells under normal pressure in the sol solution filling step described later. It becomes possible to do.

(Cut)
The obtained open cell resin foam with a skin can be processed into a predetermined size. Bubbles having an open cell structure are exposed on the cut surface. The sol solution is filled from the exposed bubbles.
By the above foam forming step, an open cell resin foam with an epidermis in which an epidermis layer having open cells is formed can be obtained.

<Foam formation process when using silicone rubber>
(material)
The raw material for the silicone rubber foam is not particularly limited, but is a raw rubber (diorganopolysiloxane with a high degree of polymerization), a siloxane compound having an alkenyl group, a siloxane compound having a Si—H group, an organic peroxide, and an organic foaming agent. Is a mixture of. A silicone rubber foam is formed by the addition reaction of these siloxane compounds or the reaction of a siloxane compound having an alkenyl group with an organic peroxide to crosslink and decompose the organic foaming agent.

Examples of the alkenyl group include a vinyl group, an allyl group, a butenyl group, a petenyl group, a hexenyl group and the like, and a vinyl group is preferable.

The organic foaming agent has a decomposition temperature of 50 to 250 ° C., and decomposes by heating in silicone rubber to generate a gas to form a silicone rubber foam. If the decomposition temperature of the organic foaming agent is less than 50 ° C, the storage stability and handleability are inferior, and if it exceeds 250 ° C, the moldability and productivity are inferior.

The organic foaming agent is not particularly limited as long as it has a decomposition temperature of 50 to 250 ° C. and decomposes to generate nitrogen gas or carbon dioxide gas when heated to a temperature equal to or higher than the decomposition temperature. For example, azobisisobutyp. Azo compounds such as tyronitrile, 1,1'-azobis (1-acetoxy-1-phenylethane), azodicarboxylic amide; dinitrosopentamethylenete lamin, N, N-dimethyl-N, N-dinitrosoterephthal Examples thereof include nitroso compounds such as amide. When these compounds are heated to a temperature higher than the decomposition temperature, they decompose to generate nitrogen gas or carbon dioxide gas. Further, the foaming temperature can be adjusted by using an adjusting agent such as urea or an organic acid in combination with these organic foaming agents.

Among these, an organic foaming agent having a decomposition temperature of 80 to 200 ° C. is preferably used from the viewpoint of moldability and handleability. The blending amount of the organic foaming agent is preferably 0.02 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the siloxane compound having an alkenyl group.

The organic peroxide further promotes cross-linking during foaming to form a silicone rubber foam having higher strength. The organic peroxide is not particularly limited as long as the decomposition temperature is equal to or higher than the decomposition temperature of the organic foaming agent. For example, benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, p-chlorobenzoyl peroxide, and dicumylper. Oxide, 2,5-bis (t-butylperoxy) -2,5-dimethylhexane, 2,5-bis (t-butylperoxy) -2,5-dimethylhexine, di-t-butylper Examples thereof include oxides, t-butylperoxybenzoate, and bis (4-t-butylcyclohexyl) -peroxydicarbonate.

These organic peroxides are appropriately selected depending on the decomposition temperature of the organic foaming agent used, but are preferably 10 to 60 ° C. higher than the decomposition temperature from the viewpoint of moldability and handleability. The blending amount of the organic peroxide is preferably 0.1 to 20 parts by mass, more preferably 1 to 10 parts by mass with respect to 100 parts by mass of the siloxane compound having an alkenyl group.

Reinforcing inorganic fillers such as silica powder, metal carbonate, clay, talc, mica, titanium oxide, processing aids such as silicone oil, conductive fillers such as carbon black, pigments, viscosity modifiers, antioxidants, etc. , Other additives can be used as needed.

Further, in the reaction, transition metals of Groups 8 to 10 in the periodic table and their complexes can be used as catalysts. Platinum compounds can be preferably used. The reaction is promoted by these catalysts, and the silicone rubber foam can be formed more efficiently.

(Preparation of raw materials)
In the raw material preparation, a raw material mixture of the open cell resin foam with a skin is prepared by mixing each of the raw materials as described above. The mixing method at this time is not particularly limited, but for example, it can be uniformly kneaded and prepared by a mixing means such as a universal kneader or a kneader.

In addition, a masterbatch, a base compound, or the like in which components involved in foaming and a catalyst are kneaded may be separately prepared in advance, and these may be mixed and used immediately before use.

(Molding)
Examples of the method for forming a silicone rubber foam having a uniform thickness such as a single shape or a three-dimensional shape include molding methods such as extrusion molding, calendar molding, and mold molding.

(Foaming / heating)
By heat-treating the resin foam raw material obtained as described above at a temperature equal to or higher than the decomposition temperature of the organic foaming agent, a silicone rubber foam with a skin can be obtained. The temperature of the heat treatment is not particularly limited as long as it is equal to or higher than the decomposition temperature of the organic foaming agent, but is preferably a temperature 50 to 150 ° C. higher than the decomposition temperature. Examples of the heat treatment method include an open heat treatment method.

(Epidermis layer formation process)
In the above-mentioned foam forming step, when the epidermis layer containing open cells is not formed on the surface of the foam layer having open cells, or when the formation of the epidermis layer is insufficient and the airgel easily falls off, the following Prior to the sol solution filling step, which is a step, the foam can be formed with an epidermis layer.

Examples of the method for forming the epidermis layer in this step include heat treatment of the foam layer having open cells by a heat press machine or a heat roll machine. The conditions for forming the epidermis layer can be appropriately selected depending on the material and the like. For example, the foam layer having open cells is pressed by using a heated hot press machine to form the foam layer having open cells. An epidermis layer can be formed on the surface of the. Examples of the pressing conditions include a condition in which the press machine is heated to 250 ° C., a pressure of 200 kg / cm ^{2 is} applied, and the press is pressed for 5 minutes.

(Cut)
The obtained open cell resin foam with a skin can be processed into a predetermined size. Bubbles having an open cell structure are exposed on the cut surface. The sol solution is filled from the exposed bubbles.
By the above foam forming step, an open cell resin foam with an epidermis in which an epidermis layer having open cells is formed can be obtained.

<< Sol solution filling process >>
Hereinafter, the method for producing silica airgel, which is a preferable example, will be described in detail as an example, but the present invention is not limited to silica airgel.

<Sol solution>
(Raw material for sol solution)
Silicone alkoxide or a derivative thereof or an alkali metal silicate can be used as a silicone raw material for silica airgel, and is mixed with an aqueous solvent to prepare a sol solution.

The silicone raw material is not particularly limited as long as the effect of the present invention is not impaired. Examples of the silicone alkoxide and its derivatives include tetramethoxysilane, tetraethoxysilane, tetramethoxysilane oligomer, tetraethoxysilane oligomer, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, and vinyltri. Examples thereof include methoxysilane, vinyltriethoxysilane, hexyltrimethoxysilane, monohexyltriethoxysilane and the like. Examples of the alkali metal silicate include potassium silicate and sodium silicate. A plurality of the silicone raw materials can be used in combination. When a plurality of them are used, the combination and the blending ratio can be selected according to the purpose.

For hydrolysis of the silicone raw material, it is preferable to use water and a solvent that is compatible with water and dissolves the silicone raw material. Examples of the solvent include alcohols such as methanol, ethanol, isopropanol and butanol, aliphatic diols such as ethanediol, propanediol, butanediol, diethylene glycol, dipropylene glycol, polyethylene glycol and polypropylene glycol, hydride bisphenol A and bisphenol. A, aromatic diols such as cyclohexanediol or alicyclic diols, polyhydric alcohols such as glycerin, diglycerin, trimethylpropane, trishydroxymethylaminopentane, pentaerythritol, dipentaerythritol, hexamethylolmelamine, hexane, toluene, Examples thereof include chloroform, diethyl ether, tetrahydrofuran, ethyl acetate, acetone, acetonitrile and the like. These solvents may be used alone or in combination of two or more.

In order to efficiently hydrolyze the silicone raw material, it is preferable to add a catalyst to the reaction system in advance. The catalyst is not particularly limited as long as the effect of the present invention is not impaired. For example, the acidic catalyst includes formic acid, acetic acid, succinic acid, malic acid, citric acid, hydrochloric acid, nitrate, boric acid, sulfuric acid, carbonic acid, and the like. As a basic catalyst, phosphoric acid and the like include metal oxides such as sodium hydroxide and potassium hydroxide and / or hydroxides, dimethylamine, triethylamine, N, N-dimethylbenzylamine, aniline, 1,5-naphthalene. Examples thereof include aliphatic and / or aromatic amines such as diamine, ammonia, divalent metal naphthenic acid, and divalent metal hydroxide. These catalysts may be used alone or in combination of two or more.

(Filling method)
The method for filling the sol solution is not particularly limited as long as it is carried out under normal pressure or reduced pressure, and a known method can be used. For example, a method of completely impregnating the prepared sol solution with the open cell resin foam with a skin obtained by the above-mentioned method under reduced pressure and the like can be mentioned. In particular, when the air permeability is 10 cm ³ / cm ² / sec or more, filling under normal pressure is possible.

Specifically, for example, a sol solution in which tetramethoxysilane (hereinafter referred to as TMOS): methanol: water: catalyst (ammonia) is mixed at a molar ratio of 1: 7.2: 4: 0.01 is taken as an example. By placing the foam in the separable flask and gradually introducing the sol solution, the foam can be completely immersed in the sol solution and the sol solution can be filled in the foam. Leave as it is for 2 to 3 hours until gelation.

Reactive functional groups such as unreacted hydroxyl groups, carboxyl groups, and amino groups remaining in the open-cell resin foam may react with a hydrophobic treatment agent described later. Since the presence of a large amount of reactive functional groups may inhibit the hydrophobic reaction of the wet gel, the reactive functional groups remaining in the open cell resin foam are inactivated in the pre-step of the sol solution filling step. You may. The method for inactivating the reactive functional group is not particularly limited, and a known method can be used.

(Gelification)
In the sol solution filled in the foam, TMOS is hydrolyzed by water and a catalyst by a sol-gel reaction, and a wet gel is formed through a sol state. Here, the wet gel means a solid state containing a liquid such as a residual liquid of a sol solution after gelation.

A wet gel is formed inside the open cells in the foam by a sol-gel reaction due to hydrolysis of a silicone alkoxide or a derivative thereof.

After forming the wet gel, there may be a step of removing water and unreacted substances in the wet gel. Examples of the solvent used in this step include alcohols such as methanol, ethanol, isopropanol and butanol, acetone, acetonitrile and the like. The process is completed by immersing the foam filled with the wet gel in the solvent and replacing the solvent with a new one several times.

You may have a step of hydrophobizing the OH group on the surface of the silica airgel with a hydrophobizing agent having a functional group and a hydrophobic group that react with a hydrophilic silanol group. As the hydrophobizing agent, one having a functional group and a hydrophobic group that react with a silanol group is used. Examples of the functional group that reacts with the silanol group include a halogen, an amino group, an imino group, a carboxyl group, an alkoxyl group, and a hydroxyl group. Examples of the hydrophobic group include an alkyl group, a phenyl group, and fluorides thereof. The hydrophobizing agent may have only one type of each of the above functional group and the hydrophobic group, or may have two or more types. For example, organic substances such as hexamethyldisilazane, hexamethyldisiloxane, trimethylchlorosilane, trimethylmethoxysilane, trimethylethoxysilane, triethylethoxysilane, triethylmethoxysilane, dimethyldichlorosilane, dimethyldiethoxysilane, methyltrichlorosilane, and ethyltrichlorosilane. Examples thereof include silane compounds, and other examples include carboxylic acids such as acetic acid, formic acid and succinic acid, and organic compounds such as alkyl halides such as methyl chloride. Only one kind of hydrophobizing agent may be used, or two or more kinds may be used.

A coupling agent may be added in order to improve the adhesion between the airgel and the continuous resin foam and prevent the airgel from falling off. The coupling agent is not particularly limited as long as it can react with both the silanol group on the surface of the aerogel and the reactive functional group such as a hydroxyl group, a carboxyl group or an amino group remaining on the continuous resin foam, and any suitable coupling agent is used. Coupling agent can be used. As the coupling agent, it is preferable to use a silane coupling agent, for example, vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3 -Glysidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltri Examples thereof include methoxysilane, 3-isocyanatepropyltriethoxysilane, and tris- (trimethoxysilylpropyl) isocyanurate.

(Drying process)
The present invention includes a drying step of drying the wet gel. A known method can be used as the drying method, and the drying method is not particularly limited. When the wet gel is dried, supercritical fluid drying is preferable because the silica airgel is not easily broken. Examples of the supercritical fluid drying include a method of removing all of the solvent under the conditions of about 80 ° C. and 20 MPa while substituting carbon dioxide having a lower critical point than this solvent.

<<< Airgel composite material according to the second form >>>
The average filling rate (ratio of the volume of the filled airgel in the bubbles) occupying the individual bubbles (cells) contained in the first foam of the airgel composite material according to the second form is preferably 50% or more. It is 100%, more preferably 70% to 100%, and particularly preferably 90% to 100%. By setting the average filling rate in such a range, high heat insulation performance can be stated.

The thickness of the airgel composite material according to the second form is, for example, 0.03 to 50.0 mm, preferably 0.1 to 20.0 mm, more preferably 0.5 to 10.0 mm, and particularly. It is preferably 0.5 to 4.0 mm.

By setting the properties of the foamed base material of the airgel composite material within a predetermined range, it is possible to achieve both flexibility and suppression of powder falling.

Further, when the amount of powder falling off is small, the heat insulating effect can be maintained, which is considered to contribute to the improvement of flame retardancy.

<< Foam base material >>
The foamed base material according to the second form is a melamine foam having open cells, a polyimide foam, or a polyurethane foam obtained by compression molding, which satisfies predetermined physical properties. The polyurethane foam can be preferably used as the foamed base material according to the first form and as the foamed base material according to the second form.

The melamine foam is usually a foam made of a thermosetting melamine resin obtained by polycondensation of melamine and formaldehyde.

The polyimide foam is usually a foam made of a thermosetting polyimide resin obtained by polycondensation of an acid dianhydride and an amine compound.

In other words, the polyurethane foam obtained by heat compression molding is a polyurethane foam subjected to a heat compression step described later. By heat-compressing the polyurethane foam, the shape (average size, aspect ratio) of the bubbles and the uniformity of the bubbles can be adjusted.

The melamine foam, polyimide foam, and polyurethane foam are not particularly limited as long as they have predetermined properties, and those obtained by a general production method can be used. A general method for producing a melamine foam, a polyimide foam, and a polyurethane foam (particularly, a polyurethane foam obtained by heat compression molding) will be described later.

Having open cells means having air bubbles communicating with each other inside the foam. Since the foam has open cells, it is possible to ventilate from one surface to the other surface, and it is possible to fill the foam with an airgel raw material. Some bubbles in the foamed substrate may be closed cells.

The foamed base material is preferably a heat-compressed melamine foam or a polyimide foam obtained by carrying out a heat-compression step described later.

The density of the foam substrate is preferably 0.015~0.200g / cm ^3, more preferably from 0.040~0.150g / cm ^3, particularly preferably 0.050~0.10g / cm It is ^3.

Air permeability of the foam substrate is preferably 0.5~300cm ³ / ^cm 2 / sec, more preferably 1~200cm ³ / ^cm 2 / sec, more preferably 1~100cm ³ / ^cm 2 / It is sec, and particularly preferably 10 to 100 ^{cm 3} / cm ² / sec. In the case of 10 cm ³ / cm ² / sec or more, the airgel composite material does not need to be evacuated for a long time in the filling step described later, and can be an efficient manufacturing method.

This air permeability can be measured by using the method described in JIS L1096-7: 2010 "Fabric test method for woven fabrics and knitted fabrics: Method A (Frazier type method)".

The shape, size, and thickness of the foamed base material are the same as those of the airgel composite material.

The density of the foamed base material can be adjusted by changing the foaming ratio in the foamed material forming step described later, the heat compressibility in the heat compression step described later, and the like.

The air permeability can be adjusted by changing the density and thickness of the foamed base material. Further, both the melamine foam and the polyimide foam may be able to significantly change the cell shape and reduce the air permeability by improving the heat pressing temperature in the heat compression step described later.

<< Airgel >>
The airgel is not particularly limited as long as it is a low-density dry gel. It includes not only airgels obtained by the supercritical fluid drying method, but also xerogels obtained by a normal drying process, cryogels obtained by freeze-drying, and the like.

As the airgel, any suitable airgel component can be used. For example, you can choose from inorganic airgels such as silica aerogels and alumina aerogels, organic aerogels such as resorcinol formaldehyde aerogels (RF aerogels), cellulose nanofiber aerogels (CNF aerogels), carbon aerogels, and mixtures thereof. can. As the airgel, _{a silica airgel containing silica (SiO 2} ) can be preferably used.

<< Physical characteristics and properties of airgel composite material >>
<Powder drop rate>
The powder removal rate of the airgel composite material can be measured by a known method and is not particularly limited. For example, it is possible to perform the fir test described in JIS K6404-6: 1999 "Rubber-pulled cloth / plastic-pulled cloth test method-Part 6: Fir test" and measure the mass before and after the test. ..

Specifically, the test piece is 10 mm × 50 mm, the thickness is arbitrary, the test piece interval is 20 mm, the stroke interval is 40 mm, and the compression load is 200 gf. Calculate the drop rate. The powder removal rate (%) is calculated by (weight before test (g) -weight after test (g)) / weight before test (g) x 100. The larger the powder drop rate, the more airgel falls off.

<Thermal conductivity>
The thermal conductivity of the airgel complex can be measured by a known method and is not particularly limited. For example, JIS A1412-1: 1999 "Method for measuring thermal resistance and thermal conductivity of thermal insulating material-Part 1: Protective heat plate method (GHP method)", JIS A1412-2: 1999 "Thermal resistance of thermal insulating material" And the method for measuring thermal conductivity-Part 2: Heat flow metering method (HFM method) "can be measured.

Specifically, the thermal conductivity is measured using a heat flux meter with the upper plate temperature set to 15 ° C and the lower plate temperature set to 35 ° C. The environmental temperature is not particularly limited, but is normal temperature and normal pressure. The thickness of the sample used in the test is 5 mm or more, and if the thickness of the test sample is less than 5 mm, the test samples are laminated and the thermal conductivity is measured to evaluate the heat insulating performance.

The thermal conductivity is preferably 0.020 W / m · K or less, more preferably 0.018 W / m · K or less, and even more preferably 0.016 W / m · K or less.

<<< Manufacturing method of airgel composite material according to the second form >>>
The method for producing the airgel composite material according to the second form preferably includes the following steps.
(1) Heat compression step of heat-compressing the foam material which is a precursor of the foam base material to obtain the foam base material (2) Filling step of filling the foam base material with the airgel raw material (3) Filling the foam base material Drying process to post-dry the airgel raw material

When the foamed base material to be used in the filling step is already prepared, the heat compression step may not be performed.

In addition, the method for producing the airgel composite material may include the following steps.
(0) Foam material forming step for obtaining foam material

Hereinafter, each step will be described.

The method for producing the airgel composite material may further include steps other than the above steps.

Further, the description of the airgel in the following steps will be described in detail by taking silica aerogel, which is a preferable example, as an example.

<< Foam material forming process >>
The foam material forming step is not particularly limited as long as it can form a melamine foam, a polyimide foam or a polyurethane foam which is a foam material, and is based on a general melamine foam or a method for producing a polyimide foam. Can be implemented. Hereinafter, an example of a method for producing a melamine foam, a polyimide foam, and a polyurethane foam will be described.

<Melamine foam>
The melamine foam is made by blending melamine and formaldehyde, which are the main raw materials, or a precondensate thereof with a foaming agent, a catalyst, an emulsifier, etc., mixing them, injecting them into a mold, heating them, or irradiating them with electromagnetic waves. It can be prepared by heating, foaming, and curing the foaming raw material by means.

The molar ratio of melamine to formaldehyde for forming the precondensate is preferably melamine: formaldehyde = 1: 1.5 to 4, particularly 1: 2 to 3.5. Further, a precondensate having a number average molecular weight of 200 to 1000, particularly 200 to 400 is preferable. As the formaldehyde, formalin, which is an aqueous solution thereof, is usually used.

As the monomer for forming the precondensate, in addition to melamine and formaldehyde, when these monomers are 100 parts by mass (hereinafter, abbreviated as parts), 50 parts or less, particularly 20 parts. Various monomers can be used.

As other monomers corresponding to melamine, alkyl-substituted melamine, urea, urethane, carboxylic acid amide, dicyandiamide, guanidine, sulfrylamide, sulfonic acid amide, aliphatic amine, phenol and derivatives thereof can be used. .. Further, as the aldehydes, acetaldehyde, trimethylolacetaldehyde, acrolein, benzaldehyde, fullflor, glyoxal, phthalaldehyde, terephthalaldehyde and the like can be used.

Further, as the foaming agent, pentane, trichlorofluoromethane, trichlorotrifluoroethane and the like can be used.

Formic acid is usually used as the catalyst, and an anionic surfactant such as sodium sulfonate can be used as the emulsifier.

The electromagnetic wave irradiated to promote the curing reaction of the foamed raw material is preferably adjusted so that the power consumption thereof is 500 to 1000 kW, particularly 600 to 800 kW with respect to the foamed raw material.

<Polyimide foam>
The polyimide foam is prepared by blending an acid dianhydride and an amine compound, which are the main raw materials, or a precondensate thereof with a catalyst or the like, mixing them, injecting them into a mold, heating them, or irradiating them with electromagnetic waves. It can be prepared by generating heat, foaming, and curing the foamed raw material.

In order to form a precondensate, it is preferable to uniformly mix with an esterification solvent, and examples of the esterification solvent include lower primary alcohols such as methanol, ethanol, n-propanol, and n-butanol. These solvents may be used alone or in combination of two or more.

Examples of the catalyst include imidization catalysts such as 1,2-dimethylimidazole, benzimidazole, isoquinoline, and substituted pyridine.

The electromagnetic wave irradiated to promote the curing reaction of the foamed raw material is preferably adjusted so that the power consumption thereof is 500 to 1000 kW, particularly 600 to 800 kW with respect to the foamed raw material.

<Polyurethane foam>
The polyurethane foam can be produced, for example, by preparing a raw material mixture containing a polyol component, a polyisocyanate component, a foaming agent, other additives, and the like, molding, and foaming. Hereinafter, specific examples of the method for producing the polyurethane foam will be described.

(Raw material preparation process)
As the polyol component, a condensed polyester polyol, a lactone-based polyester polyol, or a polycarbonate-based polyol obtained by reacting a polycarboxylic acid such as adipic acid or phthalic acid with a polyol such as ethylene glycol, diethylene glycol, propylene glycol, or glycerin. Such polyester-based polyols; polypropylene glycol, polytetramethylene glycol, and polyether polyols such as modified products thereof are exemplified. The number of functional groups of hydroxyl groups and the hydroxyl value can be changed by adjusting the type, molecular weight, degree of condensation, etc. of the raw material component, and these polyol components may be used alone or in combination of two or more.

As the polyisocyanate component, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylenedi isocyanate, p-fuphenylenedi isocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2 , 2'-Diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-biphenylenediisocyanate, 3,3'-dimethoxy-4,4'-biphenylenediisocyanate, 3,3'-dichloro-4,4'-biphenylene Diisocyanate, 1,5-naphthalenediocyanate, 1,5-tetrahydronaphthalenediocyanate, tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4- Cycloheximethylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 3,3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate And so on. Further, a polyisocyanate having a valence of 3 or more may be used in combination as long as the effect of the invention is not impaired.

The catalyst is not particularly limited as long as it promotes the urethanization reaction between the polyol component and the polyisocyanate component, and N, N, N-trimethylaminoethyl piperazine, triethylamine, triethylenediamine, diethanolamine, dimethylaminomorpholine, etc. Amines such as N-ethylmorpholine and tetramethylguanidine; organic metal compounds such as tin octylate, dibutyltin dilaurate, phenylmercury propionate or lead octenoate are exemplified.

Foaming agents include inorganic gases such as nitrogen, carbon dioxide, and mixed gases thereof; such as propane, n-butane, i-butane, n-pentane, i-pentane, cyclopentane, n-hexane, cyclohexane. Saturated hydrocarbons; water and the like are exemplified. As the foaming agent, pentane, cyclopentane, hexane, cyclohexane, dichloromethane, carbon dioxide gas and the like are used in addition to water.

As an optional component, depending on the purpose of use, a silicone compound such as an organopolysiloxane, a foam stabilizer such as a fluorine-containing compound; a phosphate ester, melamine phosphate or piperazine phosphate, aluminum hydroxide, or hydroxide Flame retardants such as magnesium, antimony oxide, zinc carbonate, chlorinated paraffin, hexachlorocyclopentadiene; antiaging agents such as aromatic amines, benzoimidazoles, dithiocarbamates, phenol compounds, phosphite esters; 2 , 6-di-t-butylphenol, 2,6-di-t-butyl-4-ethylphenol, 4,4'-butylidenebis (3-methyl-6-t-butylphenol), 1,1,3-tris ( Antioxidants such as 2-methyl-4-hydroxy-5-t-butylphenyl) butane; carbon blacks, organic pigments, dyes, colorants such as master batches containing them, and the like can be blended.

When the urethanization reaction between the polyol component and the polyisocyanate component is carried out, a one-shot method, a prepolymer method, or the like is adopted. The one-shot method is a method in which a polyol component and a polyisocyanate component are directly reacted. The prepolymer method is a method in which each part of a polyol component and a polyisocyanate component is reacted in advance to obtain a prepolymer having an isocyanate group or a hydroxyl group at the terminal, and the polyol component or the polyisocyanate component is reacted with the prepolymer. Compared with the prepolymer method, the one-shot method requires only one manufacturing process and is less restricted in manufacturing conditions, and is therefore a preferable method, and the manufacturing cost can be reduced.

The thickness and density of the foamed material may be appropriately set according to the conditions of the heat compression step and the desired thickness and density of the foamed base material.

Here, with respect to the melamine foam, it is also possible to leave unreacted methylol groups in the foam material and react the methylol groups in the heat compression step described later.

The obtained foam may be processed into a predetermined size.

<< Thermal compression process >>
The foamed material obtained in the foamed material forming step is heat-compressed to plastically deform the foamed material to obtain a foamed base material having a predetermined density and air permeability.

The heat compression step can be carried out, for example, by a method of heat compression between hot plates of a compression molding machine. At this time, the temperature of the hot plate (press temperature) is preferably 100 to 250 ° C, more preferably 120 to 200 ° C, and even more preferably 150 to 180 ° C. In particular, as a restoration prevention method described later, when impregnating with a curing agent, the press temperature may be close to the curing temperature of the curing agent, and is preferably the curing temperature of the curing agent ± 10 ° C. By setting the press temperature in such a range, the shape of each bubble is desirable while the foam is sufficiently plastically deformed, and the air permeability of the obtained foamed base material can be easily set in the desired range. The heat compression time and load may be adjusted so that the foamed base material has a desired thickness.

In the heat compression step, it is preferable to carry out heat compression so that the thickness of the foamed base material / the thickness of the foamed material is 1/2 to 1/15 or 1/3 to 1/10. Within such a range, the cells of the foamed base material become dense by heat compression molding, the airgel can be suppressed from falling off, and the airgel composite material can be imparted with flexibility.

As the polyurethane foam as the foam material, a polyester-based polyurethane foam containing a polyester polyol as a polyol component is preferable. By using such a polyurethane foam, the resin component of the polyurethane foam is thermally decomposed during thermal compression, and a film can be formed on the surface of the polyurethane foam by the melt residue.

Here, when the foam is plastically deformed by thermal compression, if only thermal compression is used, a restoring force may act on the foam when the compression load is removed. Therefore, it is preferable to additionally adopt a method of maintaining the heat-compressed state of the foam (restoration prevention method).

Examples of the restoration prevention method include the above-mentioned method in which the foamed material contains an unreacted methylol group and the methylol group is reacted in the heat compression step.

The unreacted methylol group contained in the foam material can be confirmed by measuring the absorption spectrum with a Fourier transform infrared spectrometer (FT-IR), and can be confirmed from the peak intensity of the absorption spectrum in the vicinity of ^{1000 to 1100 cm -1.} The content of the methylol group can be estimated. Further, unreacted methylol groups remain in the foamed base material obtained by heat-compressing the foamed material, and the content of the methylol groups can be estimated by the same method.

In addition, as a restoration prevention method, there is also a method in which a curing agent impregnation step of preliminarily impregnating the foamed material before the heat compression step is provided, and the curing agent is thermally cured by the heat compression step. A plurality of types and / or a plurality of restoration prevention methods may be implemented. In particular, when the foamed material is a melamine foam, it is preferable to carry out a curing agent impregnation step.

The curing agent in the curing agent impregnation step is not particularly limited as long as it cures by activating the curing agent in the resin by heating, and examples thereof include melamine resin, epoxy resin, and phenol resin.

In the curing agent impregnation step, the amount of the curing agent impregnated in the foamed material is preferably 0.5 to 10.0 parts by mass when the foamed material is 100 parts by mass. More preferably, it is 0 to 5.0 parts by mass. Within such a range, it is possible to achieve both sufficient flexibility and shape retention after the heat compression process. The curing agent impregnation step may or may not be performed. For example, when the foam material is a polyurethane foam or an imide foam, thermoforming may be performed without performing the curing agent impregnation step.

<< Epidermis layer formation process >>
In order to further enhance the function of preventing the aerogel from falling off, an epidermis layer forming step of forming the epidermis layer on the foam can be provided before the filling step which is the next step. That is, the foamed base material of the airgel composite material may have a skin layer.

Examples of the method for forming the skin layer in this step include heat treatment of the foam layer having open cells by a heat press machine or a heat roll machine, and bonding with a face material such as a fiber or a film. The conditions for forming the epidermis layer can be appropriately selected depending on the material and the like. For example, the foam layer having open cells is pressed by using a heated hot press machine to form the foam layer having open cells. An epidermis layer can be formed on the surface of the. Examples of the pressing conditions include a condition in which the press machine is heated to 250 ° C., a pressure of 200 kg / cm ^{2 is} applied, and the press is pressed for 5 minutes.

The thickness of the epidermis layer is not particularly limited, but can be, for example, 0.01 to 30 μm, preferably 0.01 to 15 μm, and more preferably 0.01 to 10 μm. When the thickness of the epidermis layer is within such a range, the powder falling prevention property is enhanced.

<< Filling process >>
In the present invention, the silica airgel raw material includes both a sol solution which is a raw material solution for silica airgel and a wet gel obtained by gelling the sol solution.

<Raw material for sol solution>
Silicone alkoxide or a derivative thereof or an alkali metal silicate can be used as a silicone raw material for silica airgel, and is mixed with an aqueous solvent to prepare a sol solution.

The silicone raw material is not particularly limited as long as the effect of the present invention is not impaired. Examples of the silicone alkoxide and its derivatives include tetramethoxysilane, tetraethoxysilane, tetramethoxysilane oligomer, tetraethoxysilane oligomer, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, and vinyltri. Examples thereof include methoxysilane, vinyltriethoxysilane, hexyltrimethoxysilane, monohexyltriethoxysilane and the like. Examples of the alkali metal silicate include potassium silicate and sodium silicate. A plurality of the silicone raw materials can be used in combination. When a plurality of them are used, the combination and the blending ratio can be selected according to the purpose.

For hydrolysis of the silicone raw material, it is preferable to use water and a solvent that is compatible with water and dissolves the silicone raw material. Examples of the solvent include alcohols such as methanol, ethanol, isopropanol and butanol, aliphatic diols such as ethanediol, propanediol, butanediol, diethylene glycol, dipropylene glycol, polyethylene glycol and polypropylene glycol, hydride bisphenol A and bisphenol. A, aromatic diols such as cyclohexanediol or alicyclic diols, polyhydric alcohols such as glycerin, diglycerin, trimethylpropane, trishydroxymethylaminopentane, pentaerythritol, dipentaerythritol, hexamethylolmelamine, hexane, toluene, Examples thereof include chloroform, diethyl ether, tetrahydrofuran, ethyl acetate, acetone, acetonitrile and the like. These solvents may be used alone or in combination of two or more.

In order to efficiently hydrolyze the silicone raw material, it is preferable to add a catalyst to the reaction system in advance. The catalyst is not particularly limited as long as the effect of the present invention is not impaired. For example, the acidic catalyst includes formic acid, acetic acid, succinic acid, malic acid, citric acid, hydrochloric acid, nitrate, boric acid, sulfuric acid, carbonic acid, and the like. As a basic catalyst, phosphoric acid and the like include metal oxides such as sodium hydroxide and potassium hydroxide and / or hydroxides, dimethylamine, triethylamine, N, N-dimethylbenzylamine, aniline, 1,5-naphthalene. Examples thereof include aliphatic and / or aromatic amines such as diamine, ammonia, divalent metal naphthenic acid, and divalent metal hydroxide. These catalysts may be used alone or in combination of two or more.

<Filling method>
The method of filling the sol solution is usually carried out under normal pressure or reduced pressure.

The filling method of the sol solution is not particularly limited, and a known method can be used. For example, a method of completely impregnating the prepared sol solution with the foamed base material obtained by the above-mentioned method under reduced pressure and the like can be mentioned.

Specifically, for example, a sol solution in which tetramethoxysilane (hereinafter referred to as TMOS): methanol: water: catalyst (ammonia) is mixed at a molar ratio of 1: 7.2: 4: 0.01 is taken as an example. By placing the foamed base material in the separable flask and gradually introducing the sol solution, the foamed base material can be completely immersed in the sol solution and the sol solution can be filled in the foamed base material. Leave as it is for 2 to 3 hours until gelation.

<Gelization>
In the sol solution filled in the foamed substrate, TMOS is hydrolyzed by water and a catalyst by a sol-gel reaction, and a wet gel is formed through a sol state. Here, the wet gel means a solid state containing a liquid such as a residual liquid of a sol solution after gelation.

A wet gel is formed inside the open cells in the foamed substrate by a sol-gel reaction due to hydrolysis of a silicone alkoxide or a derivative thereof.

After forming the wet gel, there may be a step of removing water and unreacted substances in the wet gel. Examples of the solvent used in this step include alcohols such as methanol, ethanol, isopropanol and butanol, acetone, acetonitrile and the like. The process is completed by immersing the foamed substrate filled with the wet gel in the solvent and replacing the solvent with a new one several times.

You may have a step of hydrophobizing the OH group on the surface of the silica airgel with a hydrophobizing agent having a functional group and a hydrophobic group that react with a hydrophilic silanol group. As the hydrophobizing agent, one having a functional group and a hydrophobic group that react with a silanol group is used. Examples of the functional group that reacts with the silanol group include a halogen, an amino group, an imino group, a carboxyl group, an alkoxyl group, and a hydroxyl group. Examples of the hydrophobic group include an alkyl group, a phenyl group, and fluorides thereof. The hydrophobizing agent may have only one type of each of the above functional group and the hydrophobic group, or may have two or more types. For example, organic substances such as hexamethyldisilazane, hexamethyldisiloxane, trimethylchlorosilane, trimethylmethoxysilane, trimethylethoxysilane, triethylethoxysilane, triethylmethoxysilane, dimethyldichlorosilane, dimethyldiethoxysilane, methyltrichlorosilane, and ethyltrichlorosilane. Examples thereof include silane compounds, and other examples include carboxylic acids such as acetic acid, formic acid and succinic acid, and organic compounds such as alkyl halides such as methyl chloride. Only one kind of hydrophobizing agent may be used, or two or more kinds may be used.

A coupling agent may be added in order to improve the adhesion between the airgel and the foamed base material and prevent the airgel from falling off. The coupling agent is not particularly limited, and any suitable coupling agent can be used. As the coupling agent, it is preferable to use a silane coupling agent, for example, vinyltrimethoxysilane, vinyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3 -Glysidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltri Examples thereof include methoxysilane, 3-isocyanatepropyltriethoxysilane, and tris- (trimethoxysilylpropyl) isocyanurate.

<< Drying process >>
A drying step of drying the silica airgel raw material (wet gel) is included. A known method can be used as the drying method, and the drying method is not particularly limited.

When the wet gel is dried, supercritical fluid drying is preferable because the silica airgel is not easily broken. Examples of the supercritical fluid drying include a method of removing all of the solvent under the conditions of about 80 ° C. and 20 MPa while substituting carbon dioxide having a lower critical point than this solvent.

<<<<< External layer >>>>>
The airgel laminated structure contains a second foam and / or fiber as an outer layer.

From the surface of the foam layer, the outer layer includes a second foam, a fibrous body, a second foam / second foam, a fibrous body / fibrous body, a second foam / fibrous body, and a fibrous body /. Like the second foam, the layer structure may be provided in an appropriate order. It is also possible to further laminate a fiber body or a second foam body on these layer structures.

As described above, the layers may be laminated via the pressure-sensitive adhesive layer or may be directly laminated without the pressure-sensitive adhesive layer.

As described above, the outer layer may be provided on only one surface of the airgel composite material, or may be provided on both sides of the airgel composite material.

The thickness of the outer layer on one side of the foam layer is not particularly limited and can be appropriately designed according to the intended use, but may be, for example, 0.1 to 20 mm, 5 to 20 mm, or the like.

By laminating the outer layer on the airgel composite material, it is possible to prevent powder from falling from the airgel composite material and improve the heat insulating property of the airgel laminated structure while maintaining the flexibility of the airgel laminated structure. Further, by using a second foam or fiber body having excellent heat insulating performance, for example, a composite material with airgel as the outer layer, the heat insulating property of the airgel laminated structure can be further improved.

<< Second foam >>
The material of the second foam is not particularly limited, and depending on the application, a polyolefin-based foam, an acrylic-based foam, a urethane-based foam, a vinyl acetate-based foam, a vinyl chloride-based foam, and an epoxy-based foam. It may be a body, a rubber-based foam, a silicone resin-based foam, a melamine resin-based foam, an imide resin-based foam, or the like.

The second foam may contain components (various additives and the like) other than the resin component.

The physical properties and structure of the second foam are not particularly limited, and can be appropriately designed according to the intended use. For example, the second foam can have a thickness of 0.1 to 20 mm and a density of 0.010 to 0.200 g / cm ³ . The second foam may be a closed cell resin foam or an open cell resin foam.

The second foam may be the same as or different from the first foam.

<< Fiber >>
The fiber body is usually a fiber sheet composed of fibers. When the fiber body is a fiber sheet, it may be a woven fabric or a non-woven fabric.

The fibers constituting the fiber body are not particularly limited, and can be selected from metal fibers, organic fibers, inorganic fibers and the like depending on the intended use. More specifically, the fibers are metal fibers such as stainless steel fibers, nickel fibers, copper fibers, aluminum fibers, silver fibers, gold fibers, and titanium fibers; polyparaphenylene benzoxazole, polyethylene terephthalate (PET) resin. , Polyvinyl alcohol (PVA), polyolefin resin such as polyethylene and polypropylene, polyvinyl chloride resin, aramid resin, acrylic resin, polyimide resin, polyparaphenylene benzoxazole (PBO) fiber, cellulose, vinylon, nylon, rayon , Aramid, phenolic fiber, fluorine fiber, pulp (fiber), kenaf, hemp, bamboo fiber and other organic fibers; glass fiber, carbon fiber, silica fiber, rock wool, slag wool, alumina fiber, ceramic fiber Inorganic fibers such as; etc.;

The fiber body may be a fiber reinforced resin material containing fibers and a resin component (preferably a thermosetting resin). As the resin component in this case, a conventionally known thermosetting resin (phenol resin, melamine resin, etc.) usually used as a fiber reinforced resin material can be used, and for example, heat resistance or a first foam. It can be appropriately selected in consideration of the adhesion of the resin. The fibrous body may contain various additive components.

The fibrous body preferably contains carbon fibers as fibers. Further, the fiber body preferably contains a carbon fiber woven fabric, and is preferably a fiber reinforcing material obtained by impregnating the carbon fiber woven fabric with a thermosetting resin and curing it. By manufacturing a carbon fiber composite material having an airgel composite material as a core material, excellent heat insulating performance can be imparted.

The fibrous body may contain a component other than the fiber (for example, a binder or the like).

The physical properties and structure of the fiber body are not particularly limited, and can be designed according to the application. For example, the fiber body may have an average fiber diameter of 2 to 30 μm, a thickness of 0.1 to 20 mm, a basis weight of 5 to 300 g / m ² or 5 to 200 g / m ^2, etc. can.

<<<<<< Manufacturing method of airgel laminated structure >>>>>>
The airgel laminated structure can be manufactured, for example, by carrying out a step of laminating an outer layer (second foam and / or the fibrous body) on at least one side of the airgel composite material.

The airgel composite material and the outer layer may be laminated via an adhesive or the like. In this case, the type of adhesive, the amount of coating, and the like can be appropriately designed according to the application and the material of each layer.

The adhesive is not particularly limited, and any adhesive can be used as long as the effect of the present invention is not impaired. For example, a liquid isocyanate which is inexpensive and has good adhesiveness can be mentioned. This liquid isocyanate is a moisture-curable type, that is, it reacts and cures by reaction with water (which may be moisture in the air) in the presence of heat and a catalyst, and the curing causes the liquid isocyanate to function as an adhesive. .. Aromatic TDI (Toluene Diisocyanate), Polymeric MDI (4,4'diphenylmethane Diisocyanate), NDI (1,5-Naphthalenediocyanate), TODI (Trizine Diisocyanate), PPDI (Parafene diisocyanate), XDI (Xylene Diisocyanate) , TMXDI (tetramethylxylene diisocyanate) and variants thereof and the like can be exemplified. Preferably, it is suitable to use a polymeric MDI, a modified TDI having various modifications such as urethane modification, allophanate modification, burette modification, carboimide / uretonimine modification, a modified TDI such as modified MDI, or a mixture thereof. ing.

Of these, liquid isocyanates having a viscosity of 3 to 300 cP are more preferable because they are excellent in permeability, coatability, and the like. Further, among these, especially polymeric MDI has a low vapor pressure and a good affinity with glass fiber as an inorganic fiber, and is suitable in terms of reactivity, adhesiveness, and workability. The types of these liquid isocyanates are appropriately selected and used according to the adhesiveness, the rigidity of the laminated product, the reactivity, the workability, etc., and only one type may be used, or two or more types may be used in combination. ..

Further, it may include a step of laminating the layers constituting the airgel composite material, and then heat-compressing the whole with an adhesive or the like, if necessary, to integrate the layers.

When the fiber body contains a thermosetting resin material, the heat compression step is performed in a state where the fiber body containing the resin before heat curing is laminated on the foam material, thereby heat-compressing the foam base material (first foam body). (Formation of) and thermosetting the thermosetting resin material (formation of the fiber-reinforced resin material) can be carried out at the same time. It is also possible to separately manufacture the fiber body (fiber reinforced resin material) containing the thermosetting resin after thermosetting and the first foam, and to laminate them via an adhesive or the like if necessary. be.

When the airgel composite material and the outer layer are laminated via an adhesive, if a foam with a skin is used as the first foam, the skin prevents the adhesive from impregnating the inside of the foam. The ease of manufacturing the airgel laminated structure is improved. Since such a foam with a skin can suppress the aerogel from falling off (powder falling off), it also contributes to the suppression of aged deterioration of the heat insulating performance.

<<<<<< Applications of airgel laminated structure >>>>>>
The airgel laminated structure can be thermoformed and used as an airgel molded product.
Since the airgel laminated structure is superior in heat insulating performance and heat shielding performance as compared with the existing heat insulating material, the thickness of the laminated material can be reduced. Therefore, even when the space is arranged in a narrow space, sufficient heat insulation performance and heat insulation performance can be exhibited without pressing the space. Further, since the aerogel laminated structure is excellent in flexibility (shape followability), molding processability, etc., it can be applied to various applications, for example, automobiles, railroad vehicles, aircrafts, ships, etc. As ceiling materials installed inside the roof of vehicles, as heat insulation members / cold insulation members, cold insulation boxes for food, medical care, pharmaceuticals, freezer / refrigerators, freezer / refrigerator showcases, ice makers, kitchen equipment, etc. Freezing / refrigerating equipment can be configured.

Hereinafter, the airgel laminated structure of the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

<<< Silica Airgel Composite >>>
The first foam was modified to produce multiple types of silica airgel composites.

<< Manufacturing method of open cell resin foam >>
<Manufacturing method of polyolefin foam with epidermis>
(Polymer resin)
-Random polypropylene-Low density polyethylene-EPDM (ethylene content 29.5%, diene content 5%)
(Additive)
・ Nonionic surfactant (polyoxyethylene stearylamine)
・ Nuclear agent (wet silica)
・ Phenolic antioxidant

・ Example 1
(Preparation of resin foam raw material, foam formation process)
58 parts by weight of random polypropylene, 15 parts by weight of low density polyethylene, 20 parts by weight of EPDM (ethylene content 29.5%, diene content 5%), 1.5 parts by weight of polyoxyethylene stearylamine, 5 parts by weight of wet silica, phenol 0.2 parts by weight of the antioxidant was melt-kneaded, impregnated with carbon dioxide in a supercritical state, and then foamed by releasing the pressure to obtain a polyolefin foam 1 with a skin by extrusion molding. The production conditions are an impregnation temperature of 180 ° C., an impregnation pressure of 13 MPa, and an impregnation time of 20 minutes.

-Example 9
A polyolefin foam 2 with a skin was obtained in the same manner as in Example 1 except that the production conditions such as impregnation pressure and impregnation time were adjusted so that the density was 0.05 g / cm ^3.

Example 10
A polyolefin foam 3 with a skin was obtained in the same manner as in Example 1 except that the production conditions such as impregnation pressure and impregnation time were adjusted so that the density was 0.28 g / cm ^3.

Example 14
A polyolefin foam 4 with a skin was obtained in the same manner as in Example 1 except that the amount of the nucleating agent was 3 parts by weight.

Example 15
A polyolefin foam 5 with a skin was obtained in the same manner as in Example 1 except that the amount of the nucleating agent was 7 parts by weight.

-Example 16
A polyolefin foam 6 with a skin was obtained in the same manner as in Example 1 except that the amount of the nucleating agent was 9 parts by weight.

・ Comparative example 2
A polyolefin foam 7 with a skin was obtained in the same manner as in Example 1 except that the production conditions such as impregnation pressure and impregnation time were adjusted so that the density was 0.40 g / cm ^3.

<Manufacturing method of polyolefin foam without skin>
-Example 8
The epidermis layer of the polyolefin foam 1 with an epidermis was sliced and removed to obtain a polyolefin foam without an epidermis. The thickness of the skinless polyolefin foam after slicing was 1 mm.

<Manufacturing method of open cell resin foam with skin using water-dispersible resin dispersion>
(Water-dispersible resin dispersion)
・ Water-dispersible resin dispersion 1
Polyether carbonate-based urethane emulsion (stable dispersion type water-dispersible resin; precipitation rate 0.8%), pH 8, solid content 60%
・ Water-dispersible resin dispersion 2
Acrylonitrile / acrylic acid alkyl ester / itaconic acid copolymer (stable dispersion type water-dispersible resin; precipitation rate 4.9%), pH 9, solid content 60%
・ Water-dispersible resin dispersion 3
Acrylonitrile-butadiene rubber latex (unstable dispersion type water-dispersible resin; precipitation rate 33%), pH 11, solid content 40%
(Anionic surfactant)
-Anionic surfactant 1 (sodium alkyl sulfosuccinate derived from beef tallow)
Dispersion medium; water, pH 9.4, solid content 30%
-Anionic surfactant 2 (ammonium stearate)
Dispersion medium; water, pH 11, solid content 30%
・ Anionic surfactant 3 (potassium oleate soap)
Dispersion medium; water, pH 11.2, solid content 30%
(Hardener)
Hydrophobic HDI isocyanurate (3.5 functional groups, trimer)
(Vulcanized paste)
10 parts by mass of sulfur, 6 parts by mass of thiazole-based vulcanization accelerator, 18 parts by mass of zinc oxide, 13 parts by mass of anti-aging agent, and 3 parts by mass of dispersant in 50 parts by mass of ion-exchanged water. In addition, a vulcanized paste was prepared by dispersing in a ball mill for 48 hours.
(Foam suppressant)
Trimen Base (manufactured by Uniroyal)
(Gel agent)
Sodium silicate

-Example 2
(Preparation of resin foam raw material)
Using the urethane emulsion of the water-dispersible resin dispersion 1 as the main agent, 3 parts by mass of anionic surfactant 1 and 3 parts by mass of anionic surfactant 2 and 6 parts by mass are cured with respect to 100 parts by mass of the main agent. The agents were mixed to obtain a resin foam raw material.

(Foam form forming process)
Air was added to the prepared resin foam raw material to foam it, and the resin foam was cast on a release-treated PET film (thickness 38 μm) to form a film using a doctor knife. The doctor knife was set so that the thickness of the foam after heating, which will be described later, was 2 mm. The obtained film-like resin foam was heated in an oven at 80 ° C. for 1 hour to completely dry the moisture, and a polyurethane foam with a skin was obtained.

・ Example 3
As the water-dispersible resin dispersion, the water-dispersible resin dispersion 2 which is an acrylic emulsion is used as the main agent, and 3 parts by mass of the anionic surfactant 1 and 3 parts by mass of the anionic interface with respect to 100 parts by mass of the main agent. An acrylic foam with a skin was obtained in the same manner as in Example 2 except that a curing agent of 2 to 3 parts by mass of an activator was mixed to obtain a resin foam raw material.

・ Example 4
As the water-dispersible resin dispersion, the water-dispersible resin dispersion 3 which is a rubber latex is used as the main agent, and 7.6 parts by mass of the vulcanized paste and 0.2 parts by mass of the anion are used with respect to 100 parts by mass of the main agent. Acrylonitrile-butadiene rubber with skin in the same manner as in Example 2, except that the sex surfactant 3, 0.4 parts by mass of a defoaming inhibitor and 10 parts by mass of a gelling agent were mixed to prepare a resin foam raw material. A foam was obtained.

・ Example 12
A polyurethane foam 2 with a skin was obtained in the same manner as in Example 2 except that the doctor knife was set so that the thickness of the foam after heating was 0.1 mm.

-Example 13
A polyurethane foam 3 with a skin was obtained in the same manner as in Example 2 except that the doctor knife was set so that the thickness of the foam after heating was 40.0 mm.

<Manufacturing method of silicone foam with skin>
(Silicone resin foam raw material)
Silicone resin 1: Polyorganosiloxane having a vinyl group (manufactured by Momentive Performance Materials Japan GK: XE18-C1103 (A)) Platinum catalyst-containing silicone resin 2: Polyorganohydrogensiloxane (Momentive Performance Materials)・ Made by Japan GK: NI-0539 (B))
Foaming aid: Fluoro-modified silicone oil

・ Example 5
(Preparation of resin foam raw material)
Silicone resin 1 and silicone resin 2 were mixed at a mass ratio of 100:13 to obtain a silicone resin foam raw material.

(Foam form forming process)
Air was added to the prepared resin foam raw material to foam it, and the resin foam was cast on a release-treated PET film (thickness 38 μm) to form a film using a doctor knife. The doctor knife was set so that the thickness of the foam after heating, which will be described later, was 2 mm. The obtained film-like raw material was heated at 150 ° C. for 1 hour to complete the curing reaction, and a silicone resin foam with a skin was obtained.

<Manufacturing method of thermoformed melamine foam>
(Foam material)
・ Melamine foam 1
Melamine foam with unreacted methylol groups, density 0.010 g / cm ³
・ Melamine foam 2
Melamine foam with unreacted methylol groups, density 0.040 g / cm ³

-Example 6
(Thermal compression process)
A melamine foam 1 having an unreacted methylol group having a thickness of 10.0 mm is used as a foam material, and the foam material is used between the hot plates of a compression molding machine so as to be a foam base material having a thickness of 1.4 mm at a press temperature of 160 ° C. Heat-compressed with.

・ Example 11
Melamine foam 2 having an unreacted methylol group having a thickness of 10.0 mm was used as a foaming material and was thermoformed in the same manner as in Example 6 except that it was thermoformed so as to be a foamed base material having a thickness of 1.8 mm. I got body 2.

・ Example 17
A melamine foam 3 was thermoformed in the same manner as in Example 6 except that it was heat-compressed at a press temperature of 230 ° C.

Example 18
A melamine foam 4 having a thickness of 1.0 mm and having an unreacted methylol group was obtained by thermoforming in the same manner as in Example 6 except that the melamine foam 1 having an unreacted methylol group was used as a foam material.

-Example 19
A melamine foam 5 having a thickness of 40.0 mm and having an unreacted methylol group was obtained by thermoforming in the same manner as in Example 6 except that the melamine foam 1 having an unreacted methylol group was used as a foam material.

<Manufacturing method of thermoformed polyurethane foam>
(Foam material)
-Polyurethane foam Polyester foam, density 0.015 g / cm ³

-Example 7
(Thermal compression process)
A polyester polyurethane foam having a thickness of 10.0 mm was used as a foam material, and the foam material was heat-compressed between hot plates of a compression molding machine so as to be a foam base material having a thickness of 1.4 mm at a press temperature of 160 ° C.

<< Manufacturing method of airgel composite material >>
(Gel raw material)
Tetramethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.)
(solvent)
・ Solvent 1
Methanol (manufactured by Wako Pure Chemical Industries, Ltd.)
・ Solvent 2
Ion-exchanged water, electrical resistivity 1 x 1010 Ω · cm or more (catalyst)
25% ammonia water (manufactured by Wako Pure Chemical Industries, Ltd.)

・ Example 1
(Preparation of sol solution)
Tetramethoxysilane was used as the main agent, and 7.2 mol of methanol, 4 mol of ion-exchanged water, and 0.01 mol of the catalyst were mixed with 1 mol of the main agent to prepare a sol solution.

(Sol solution filling process)
The open cell resin foam with a skin was cut into a size that can be stored in a separable flask and stored with the skin layer attached. The prepared sol solution was added until the open cell resin foam with a skin was completely immersed, and allowed to stand under normal pressure for 3 hours to obtain an open cell resin foam with a skin filled with a wet gel.

The obtained open-cell resin foam with a skin filled with the wet gel was immersed in ethanol, and ethanol was repeatedly exchanged with stirring to carry out solvent substitution for 24 hours. Next, in order to hydrophobize the gel surface, the gel was immersed in an ethanol solution (concentration: 20% by mass) of hexamethyldisilazane, and the hydrophobizing treatment was performed for 24 hours with stirring.

(Drying process)
The open-cell resin foam with a skin having a hydrophobic gel surface was impregnated with carbon dioxide at 80 ° C. and 20 MPa, and supercritical fluid drying was carried out for 12 hours to obtain an airgel composite material of Example 1. The filling rate of airgel in the airgel composite was 95%.

-Examples 2 to 21, Comparative Examples 1 and 2
An airgel composite material was obtained in the same manner as in Example 1 except that the open cell resin foam shown in each table was used.

<<<<< Airgel laminated structure >>>>>
<<< Preparation of Example 1 >>>
The skin-filled polyolefin foam 1 filled with silica airgel was ^{impregnated with a 450 g / m 2} isocyanate-based binder (crude methylene diphenyl diisocyanate). Glass fiber mats (glass fiber non-woven fabric, average fiber diameter 12 μm, thickness 1 mm, grain amount: 100 g / m ² ) are placed on both sides of the foam 1, a surface material (polyester non-woven fabric) is placed on one surface of the glass mat, and the other surface is covered. The back surface materials (polypropylene hot melt film and polypropylene non-woven fabric laminate) were laminated, respectively, and an aerogel laminated structure was obtained by hot pressing (hot press, 120 ° C.). The glass fiber mat was impregnated with a binder by exuding from the foam 1 by compression during hot pressing. The surface material was adhered by a binder impregnated into the glass fiber mat and leached onto the surface of the glass fiber mat, and the back surface material was adhered by welding a hot melt film.

<<< Preparation of Examples 2 to 19 and Comparative Examples 1 and 2 >>>
An airgel laminated structure was obtained in the same manner as in Example 1 except that the open cell resin foam shown in each table was used.

<<< Preparation of Example 20 >>>
An airgel laminated structure was obtained in the same manner as in Example 1 except that a glass fiber mat was laminated on one side of a polyolefin foam with a skin filled with silica airgel and a surface material was laminated on one side of the glass mat.

<<< Preparation of Example 21 >>>
^{Polyurethane foam (thickness 4 mm, density 40 kg / m 3} ) is laminated on both sides of an olefin foam with a skin filled with silica airgel, and a surface material (polyester non-woven fabric) is laminated on one surface of the polyurethane foam and the back surface is on the other surface. An airgel laminated structure was obtained in the same manner as in Example 1 except that the materials (polyurethane hot melt film and polypropylene non-woven fabric laminate) were laminated.

<<< Preparation of Example 22 >>>
Carbon fiber woven fabric (carbon fiber woven fabric with a fiber weight of 200 g / m ² impregnated with phenol resin and dried at 60 ° C.) was laminated on both sides of an olefin foam with a skin filled with silica airgel, and 180 ° C. An airgel laminated structure was obtained in the same manner as in Example 1 except that heat compression was performed between the hot plates of the compression molding machine at 10 MPa for 5 minutes.

<<< Preparation of Example 23 >>>
Examples except that carbon fiber woven fabrics (carbon fiber woven fabrics having a fiber weight of 200 g / m ² impregnated with phenol resin and dried at 60 ° C.) were laminated on both sides of a melamine foam filled with silica airgel. An airgel laminated structure was obtained in the same manner as in 22.

<<< Preparation of Comparative Example 3 >>
A laminated structure was obtained in the same manner as in Example 1 except that a rigid polyurethane foam (thickness 6 mm, density 40 kg / m ^{3) was used instead of the airgel composite material.}

<<< Preparation of Comparative Example 4 >>
The laminated structure was the same as in Example 1 except that a vacuum heat insulating material (vacuum heat insulating material having glass wool as a core material, core material: average fiber diameter 10 μm, density 150 kg / m ^{3) was used instead of the airgel composite material.} I got a body.

<<< Preparation of Comparative Example 5 >>
A glass fiber mat was ^{impregnated with an isocyanate-based binder of 150 g / m 2} , and a front surface material and a back surface material were laminated, respectively, and a laminated structure was obtained by hot pressing (hot pressing, 120 ° C.).

<<< Preparation of Comparative Example 6 >>
A laminated structure was obtained in the same manner as in Example 22 except that a polyolefin foam with a skin (density 0.015 g / cm ^{3) was used instead of the airgel composite material.}

<<<<< Evaluation >>>>>
<<< Evaluation of open cell resin foam >>>
The open cell resin foams of Examples and Comparative Examples prepared as described above were evaluated according to the methods shown below.

-Measurement of average cell diameter ratio The RA and RB of the airgel composite materials of each Example and Comparative Example were determined by the following methods.
A cell photograph was taken from the normal direction of the epidermis layer using a scanning electron microscope (SEM, manufactured by KEYENCE CORPORATION, VHXD-500). Then, using the image processing software Image-ProPLUS (manufactured by Media Cybernetics, 6.3 ver), the SEM image was read and the contrast was adjusted in order to recognize the cell by the contrast. Next, the shape of the cell is read by image processing (the shape is recognized as it is, not a perfect circle). Next, select "diameter (average)" as the measurement item. Next, the diameter passing through the center of gravity of the object was measured in increments of 2 degrees, and the average value was used to calculate the diameter of each cell, which was used as RA.
A cell photograph was taken in the same manner for the cross section perpendicular to the surface of the epidermis layer, and the RB was determined.

<< Evaluation of air permeability >>
For the amount of air permeability, use a woven fabric air permeability tester (manufactured by Toyo Seiki Kogyo Co., Ltd .: KM-404P) in accordance with JIS L1096-7: 2010 "Fabric test method for woven fabrics and knitted fabrics: Method A (Frazier type method)". Those measured using were evaluated according to the evaluation criteria.

<Evaluation criteria>
"◎" means "air permeability is 25 cm ³ / cm ² / sec or more", "○" means "air permeability is 10 cm ³ / cm ² / sec or more and ^{less than 25 cm 3} / cm ² / sec", and "△" means "Air permeability is 0.5 cm ³ / cm ² / sec or more and less than 10 cm ³ / cm ² / sec", "△△" is "air permeability 0.01 cm ³ / cm ² / sec or more 0.5 cm ³ / cm" ^“2 / sec” and “x” indicate “0.01 cm ³ / cm ^{less than 2} / sec”, respectively.

<< Measurement of thermal conductivity >>
The measurement of thermal conductivity is based on JIS A 1412-2: 1999 "Measurement method of thermal resistance and thermal conductivity of thermal insulation material-Part 2: Thermal flow metering method (HFM method)". (Made by Eiko Seiki Co., Ltd .: HC-72) was used for measurement.

<<< Evaluation of Airgel Laminated Structures of Examples 1-21 and Comparative Example 1-5 >>>
The airgel laminated structures of Examples 1-21 and Comparative Example 1-5 prepared as described above were evaluated according to the methods shown below.

<< Insulation >>
The heat insulating property was measured according to the following method and evaluated according to the evaluation criteria.

<Evaluation method>
The sample was allowed to stand on a heater heated to 80 ° C. for 5 minutes, and the surface temperature of the sample was measured after 5 minutes.
The temperature change per unit thickness was calculated from the sample thickness and surface temperature.
The temperature change (° C.) per unit thickness was calculated by (heater temperature 80 (° C.)-Sample surface temperature (° C.)) / sample thickness.

<Evaluation criteria>
"◎" indicates "temperature change per unit thickness of more than 10 ° C", "○" indicates "temperature change per unit thickness of more than 5 ° C and 10 ° C or less", and "△" indicates "temperature change per unit thickness". Indicates "more than 2 ° C and 5 ° C or less", and "x" indicates that the temperature change per unit thickness is 2 ° C or less.

<< Heat shield >>
The heat shield was measured according to the following method and evaluated according to the evaluation criteria.

<Evaluation method>
An acrylic box (300 mm x 300 mm x height 500 mm) equipped with a 250 W infrared light bulb on the ceiling and a heat insulating box (250 mm x 250 mm x height 250 mm) surrounded by a rigid polyurethane foam inside the box. A 20 mm thick black iron plate and a sample were installed as a ceiling panel. In addition, a thermometer was installed at a height of 100 mm from the bottom of the heat insulating box to serve as a temperature measurement point.
The infrared light bulb was turned on, the atmospheric temperature at the temperature measurement point after 30 minutes was measured, and the temperature change from the atmospheric temperature when only the ceiling panel was used was calculated.
The temperature change (° C.) was calculated by (atmospheric temperature (° C.) after 30 minutes in the case of the ceiling panel only-atmospheric temperature (° C.) after 30 minutes in the case of the ceiling panel + sample).

<Evaluation criteria>
“◯” indicates “temperature change is 10 ° C. or less”, “Δ” indicates a temperature change of 5 ° C. or more and less than 10 ° C., and “x” indicates “temperature change is less than 5 ° C.”.

<< Flexibility >>
The flexibility (flexibility) was measured according to JIS K 7171: 2016 "Plastic-How to determine bending characteristics" and evaluated according to the evaluation criteria.

<Evaluation criteria>
“○” indicates “the test piece bends without cracking”, “Δ” indicates “breaks at a bending of more than 135 degrees and 180 degrees or less”, and “×” indicates “breaks at a bending of 135 degrees or less”.

<< Powder removal >>
The powder removal property was measured according to the following method and evaluated according to the evaluation criteria.

<Evaluation method>
The sample is processed into a test piece of 10 mm x 50 mm, and using a Scott type kneading tester (manufactured by Toyo Seiki Seisakusho), the test piece interval is 20 mm, the stroke interval is 40 mm, and the compression load is 200 gf, 1200 times (reciprocating speed 120 times / minute). ) The powder drop rate was calculated from the weight of the test piece before and after kneading.
The powder removal rate (%) was calculated by (weight before test (g) -weight after test (g)) / weight before test (g) x 100.
The larger the powder drop rate, the more airgel falls off.

<Evaluation criteria>
"◎" means "powder removal rate is 3% or less", "○" means "powder removal rate is more than 3% and 10% or less", and "△" means "powder removal rate is more than 10% and 15% or less". , "X" indicates "powder removal rate is more than 15%", respectively.

<<< Evaluation of Airgel Laminated Structures of Examples 22 and 23 and Comparative Example 6 >>>
The airgel laminated structures of Examples 22 and 23 and Comparative Example 6 were evaluated according to the methods shown below.

<< Insulation >>
The heat insulating property was evaluated in the same manner as described above.

<< Insulation >>
The heat shield was evaluated in the same manner as described above.

<< Molding workability >>
The moldability was measured according to the following method and evaluated according to the evaluation criteria.

<Evaluation method>
The test piece is heated above the softening point of the carbon fiber woven fabric and molded into a predetermined shape using a mold.
The weight change rate was calculated from the weight of the test piece before and after molding.
The weight change rate (%) was calculated by (weight before test (g) -weight after test (g)) / weight before test (g) × 100.
The larger the rate of change in weight, the more the airgel falls off from the foam and the more the airgel and foam are decomposed by heating.

<Evaluation criteria>
"○" indicates "weight change rate of 5% or less", "△" indicates "weight change rate of more than 5% and 15% or less", and "x" indicates "weight change rate of more than 15% or test piece". It cannot be molded into a predetermined shape. "

Claims (11)

An airgel laminated structure containing an airgel composite material in which the inside of the first foam is filled with airgel, and a second foam and / or fiber body provided on at least one side of the airgel composite material. hand,
The first foam is an airgel laminated structure characterized by being an open cell resin foam and having a density of 0.015 to 0.300 g / cm ^3. The first foam is an open cell resin foam with an epidermis having a foam layer having open cells and a breathable epidermis layer formed on two opposing surfaces of the foam layer. ,
The epidermis layer contains open cells that reach the surface of the epidermis layer.
The average cell diameter RA of open cells observed from the surface of the epidermis layer from the normal direction of the surface of the epidermis layer, and the average cell diameter RB of the open cells of the foam layer in a cross section perpendicular to the surface of the epidermis layer. The airgel laminated structure according to claim 1, wherein the ratio (RA / RB) of is 1/1000 to 1/2. The airgel laminated structure according to claim 2, wherein the air permeability of the first foam is 0.01 to 300 ^{cm 3} / cm ^{2 / sec.} The airgel laminated structure according to claim 2 or 3, wherein the first foam is selected from a polyolefin foam, a polyurethane foam, an acrylic foam, an acrylonitrile-butadiene rubber foam, and a silicone foam. The first foam is an open cell resin foam selected from a melamine foam, a polyimide foam, or a polyurethane foam obtained by compression molding.
The airgel laminated structure according to claim 1, wherein the first foam has a density of 0.015 ^{to 0.200 g / cm 3} and an air permeability of 0.5 to 300 ^{cm 3} / cm ^{2 / sec.} .. The airgel laminated structure according to any one of claims 1 to 5, wherein the thickness of the first foam is 0.03 to 50.0 mm. The airgel laminated structure according to any one of claims 1 to 6, wherein the fiber body is a carbon fiber woven fabric. The airgel laminated structure according to claim 7, wherein the fiber body is a fiber reinforcing material obtained by impregnating a carbon fiber woven fabric with a thermosetting resin and curing the fiber body. An airgel molded product obtained by thermoforming the airgel laminated structure according to any one of claims 7 to 8. A ceiling material comprising the airgel laminated structure according to any one of claims 1 to 8. A method for manufacturing a ceiling material including the airgel laminated structure according to claim 9.
A method for producing a ceiling material, which comprises a step of laminating the second foam and / or the fiber on at least one side of the airgel composite.

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