JP5700548B2 - Molded body, encapsulated body, and method for producing molded body - Google Patents

Description

  The present invention relates to a molded body, an encapsulated body, and a method for manufacturing the molded body.

  The mean free path of air molecules at room temperature is about 100 nm. Therefore, in a porous body having voids with a diameter of 100 nm or less, heat transfer due to air convection and conduction is suppressed, and such a porous body exhibits an excellent heat insulating effect.

It is known that ultrafine particles have a low thermal conductivity and are suitable as a heat insulating material in accordance with the principle of the heat insulating action. For example, Patent Document 1 describes a heat insulating material obtained by independently forming an ultrafine powder of silica into a porous body, and the heat insulating material has a bulk density of 0.2 to 1.5 g / cm ³ and a BET specific surface area. Is 15 to 400 m ² / g, the average particle diameter is 0.001 to 0.5 μm, the total pore volume is 0.3 to ⁴ cm ³ / g, and the average pore diameter is 1 μm or less. The cumulative pore volume of pores whose volume is 70% or more of the cumulative pore volume in the molded body and whose average pore diameter is 0.1 μm or less is 10% or more of the cumulative pore volume in the molded body. In Patent Document 2, porous particles are formed by coating particles made of a radiation absorption / scattering material or the like with ultrafine particles associated in a ring shape or a spiral shape so that the inner diameter of the ring becomes 0.1 μm or less. Is described as a method for producing a heat insulating material by pressure-molding this precursor into a powder of a heat insulating material precursor by mixing it with a porous coated fiber formed in the same manner as inorganic fibers or porous coated particles. ing.

JP 2007-169158 A Japanese Patent No. 4367612

New Energy and Industrial Technology Development Organization, 2005-2006 Achievement Report Strategic development of energy use rationalization technology Practical development of energy use rationalization technology “Practical application of ultra-low thermal conductive materials with nanoporous and composite structures” development of"

  However, as described in Non-Patent Document 1, the heat-insulating material precursor mainly composed of ultrafine particles tends to expand greatly when the pressure is released after pressure molding. This expansion is called springback. Like the silica molded body described in Patent Document 1, a molded body obtained by pressure-molding ultrafine particles containing ultrafine powder as a main component has a problem that a springback occurs and a molding defect occurs in some cases. . Certainly, the microporous structure contributes to reducing the heat conduction of the heat insulating material, but spring back is likely to occur if the air is not sufficiently vented during pressure molding. In the heat insulating material of Patent Document 2, as disclosed in Non-Patent Document 1, a crack-shaped molding defect occurs on a surface perpendicular to the press surface during pressure molding. If such a molding defect exists in the heat insulating material, the heat insulating material may be damaged, and the heat insulating performance is also deteriorated, so that it cannot be handled as a product and the yield is reduced, which is not preferable. Further, a heat insulating material mainly composed of ultrafine particles also tends to cause lamination after being pressure-molded. Lamination refers to a phenomenon in which a molded product obtained by pressure molding is peeled into two or more layers mainly in the thickness direction. If such delamination occurs, it cannot be handled as a product, and the yield decreases, which is not preferable.

  On the other hand, by reducing the amount of ultrafine particles contained in the heat insulating material precursor and reducing the springback or suppressing lamination, it is possible to suppress the occurrence of molding defects, but at a level that prevents springback and lamination. If the amount of ultrafine particles is reduced to such a level, the heat insulation performance deteriorates as the use as a heat insulating material is impaired.

  This invention is made | formed in view of the subject which such a prior art has, and aims at providing the molded object which can suppress a springback and lamination, and shows sufficient heat insulation performance. It is another object of the present invention to provide a covering body in which the formed body is accommodated in a jacket material and a method for manufacturing the formed body.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has discovered that pores having a pore diameter of 0.1 μm or more influence the likelihood of springback. Furthermore, it has been found that when the cumulative pore volume having a pore diameter of 0.1 μm or more is in a specific range, the occurrence of molding defects is small, and the present invention has been completed. That is, the present invention is as follows.

The molded body of the present invention contains silica, has pores, and has a pore diameter of 0.1 μm or more with respect to the cumulative pore volume V _0.003 of pores having a pore diameter of _0.003 μm or more and 150 μm or less. The ratio R _0.1 of the cumulative pore volume V _0.1 of the pores that is 150 μm or less is 50% or more and 85% or less, and V _0.1 is 0.2 mL / g or more to 3 mL / g or less, The thermal conductivity at 30 ° C. is 0.05 W / m · K or less. With such a molded body, it is possible to suppress spring back and lamination, so that there is little generation of molding defects and it is possible to exhibit sufficient heat insulation performance.

  In the molded body of the present invention, the molded body containing infrared opaque particles preferably has a thermal conductivity at 800 ° C. of 0.15 W / m · K or less.

  The average particle diameter of the infrared opaque particles contained in the molded product of the present invention is preferably 0.5 μm or more and 30 μm or less, and the content of the infrared opaque particles is 0 based on the total mass of the molded product. It is preferable that they are 1 mass% or more and 39.5 mass% or less.

  The molded article of the present invention contains sodium (Na), and the content of sodium (Na) is preferably 0.005 mass% or more and 3 mass% or less based on the total mass of the molded article.

  The molded body of the present invention contains iron (Fe), and the content of iron (Fe) is preferably 0.005 mass% or more and 6 mass% or less based on the total mass of the molded body.

  The molded product of the present invention further contains inorganic fibers, and the content of inorganic fibers is preferably 0.1% by mass or more and 50% by mass or less based on the total mass of the molded product.

  The inorganic fibers contained in the molded article of the present invention preferably have biosolubility.

  The molded body of the present invention contains germanium (Ge), and the content of germanium (Ge) is preferably 10 ppm or more and 1000 ppm or less based on the total mass of the molded body.

  The enveloping body of this invention is provided with a covering material and the said molded object accommodated in the covering material. Such an encapsulated body not only has the excellent characteristics of the molded body of the present invention, but is also easier to handle than the molded body, and therefore has excellent workability.

  In the envelope according to the present invention, the outer covering material preferably contains inorganic fibers.

  In the envelope according to the present invention, the outer covering material is preferably a resin film.

The above process for producing a molded article of the present invention comprises a silica, and small particles having an average particle diameter D _S is at 5nm or 30nm or less, comprises silica, and large particles having an average particle diameter D _L is at 40nm or more 60μm or less , To obtain an inorganic mixture, and to form the inorganic mixture so that the bulk density of the compact is 0.25 g / cm ³ or more and 2.0 g / cm ³ or less. According to this manufacturing method, it is possible to manufacture a molded body that can suppress springback and lamination, has few molding defects, and exhibits sufficient heat insulation performance.

  ADVANTAGE OF THE INVENTION According to this invention, it is possible to provide the molded object which can suppress a springback and lamination, has few shaping | molding defects, and shows sufficient heat insulation performance.

It is a cross-sectional schematic diagram of the envelope which concerns on one Embodiment of this invention. It is a cross-sectional schematic diagram of the small particle and large particle which the molded object which concerns on one Embodiment of this invention contains.

  Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail. In addition, this invention is not limited to the following embodiment, It can implement by changing variously within the range of the summary.

[1] Molded Body The molded body of the present embodiment includes silica, has pores, and is fine with respect to the cumulative pore volume V _0.003 of pores having a pore diameter of 0.003 μm to 150 μm. The ratio R _0.1 of cumulative pore volume V _0.1 of pores having a pore diameter of 0.1 μm or more and 150 μm or less is 50% or more and 85% or less, and V _0.1 is 0.2 mL / g or more and 3 mL / The thermal conductivity at 30 ° C. is 0.05 W / m · K or less. R _0.1 may be expressed as (V _0.1 / V _0.003 ) × 100.

[1-1] Silica When the silica content in the molded body is 50% by mass or more, heat transfer due to solid conduction is small, which is preferable for a heat insulating material. It is more preferable that the silica content is 75% by mass or more of the molded body because the adhesion between the silica particles increases and the scattering of the inorganic mixture as the raw material of the molded body is reduced. In the present specification, the silica, the other components consisting of component represented by the composition formula SiO _2, refers to a material containing SiO _2, a metal component or the like in addition to SiO _2, containing other inorganic compounds Includes the composition. In addition to pure silicon dioxide, silica may contain salts and complex oxides with Si and various other elements, or may contain hydrated oxides such as hydroxides, silanols. It may have a group. Silica in the molded body may be crystalline, amorphous, or a mixture thereof. In the case of a heat insulating material, the silica in the heat insulating material It is preferable because heat transfer by solid conduction is small and heat insulation performance is improved.

  Depending on the use of the molded body, the molded body may contain materials other than silica particles. The material other than the silica particles will be described in detail later. When the molded body contains a material other than the silica particles, the content of the silica particles is 50% by mass or more and 99.9 masses based on the total mass of the molded body. % Or less is preferable. A molded product containing silica particles with a content of 50% by mass or more and 97.5% by mass or less and containing inorganic fibers and infrared opaque particles is more preferable because the effect of improving the heat insulation performance at a high temperature appears more suitably. It is more preferable that the content is 60% by mass or more and 97.5% by mass or less because the bulk density of the molded body is smaller.

  The particle size of the silica particles affects the thermal conductivity and pore volume of the molded body, and from the viewpoint of solid conduction of the silica particles, the average particle size of the silica particles is preferably 5 nm or more and less than 80 μm, preferably 10 nm or more and 50 μm. More preferably, the thickness is more preferably 10 nm or more and less than 30 μm. In the present specification, the average particle diameter is obtained by observing 1000 particles with a field emission scanning electron microscope (FE-SEM), obtaining the equivalent area equivalent circle diameter, and calculating the number average. The particle diameter is said.

[1-2] Inorganic fiber The molded body preferably contains an inorganic fiber. When the inorganic fiber is contained, there is an advantage that in the pressure molding, there is little dropout of particles from the molded body, and the productivity is high. In the present specification, the term “inorganic fiber” means that the ratio of the average length of the inorganic fiber to the average thickness (aspect ratio) is 10 or more. The aspect ratio is preferably 10 or more, and more preferably 50 or more from the viewpoint of enabling molding with a small pressure and improving the productivity of the molded body at the time of producing the molded body, from the viewpoint of bending strength of the molded body. 100 or more is more preferable. The aspect ratio of the inorganic fiber can be determined from the average value of the thickness and length of 1000 inorganic fibers measured by FE-SEM. It is preferable that the inorganic fibers are monodispersed and mixed in the molded body, but the inorganic fibers may be mixed in a state where the inorganic fibers are entangled with each other or a bundle in which a plurality of inorganic fibers are aligned in the same direction. . In the monodispersed state, the inorganic fibers may be aligned in the same direction, but from the viewpoint of reducing the thermal conductivity, the inorganic fibers are oriented in a direction perpendicular to the heat transfer direction. It is preferable.

Examples of inorganic fibers include long glass fibers (filaments) (SiO ₂ —Al ₂ O ₃ —B ₂ O ₃ —CaO), glass wool (SiO ₂ —Al ₂ O ₃ —CaO—Na ₂ O), alkali resistance Glass fiber (SiO ₂ —ZrO ₂ —CaO—Na ₂ O), rock wool (basalt wool) (SiO ₂ —Al ₂ O ₃ —Fe ₂ O ₃ —MgO—CaO), slag wool (SiO ₂ —Al ₂ O) ₃ -MgO-CaO), ceramic fibers (mullite _{fiber) (Al 2 O 3 -SiO 2} ), silica fibers _(SiO 2), alumina fibers _{(Al 2 O 3 -SiO 2)} , potassium titanate fibers, alumina whiskers, Silicon carbide whisker, silicon nitride whisker, calcium carbonate whisker, basic magnesium sulfate whisker, calcium sulfate Muwisuka (gypsum fiber), zinc oxide whisker, zirconia fiber, carbon fiber, graphite whisker, phosphate fibers, AES (Alkaline Earth Silicate) fiber _(SiO 2 -CaO-MgO), natural mineral wollastonite, sepiolite, attapulgite, Blue site can be mentioned.

Among inorganic fibers, it is preferable to use biosoluble AES fiber (Alkaline Earth Silicate Fiber) that is safe for the human body. Examples of the AES fiber include SiO ₂ —CaO—MgO-based inorganic glass (inorganic polymer).

  The average thickness of the inorganic fibers is preferably 1 μm or more from the viewpoint of preventing scattering. In the case of a heat insulating material, the thickness is preferably 20 μm or less from the viewpoint of suppressing heat transfer by solid conduction. The average thickness of the inorganic fibers can be determined by obtaining the thickness of 1000 inorganic fibers by FE-SEM and averaging the thicknesses.

  In the case of heat insulation, the content of inorganic fibers in the molded body is preferably 0.1% by mass or more with respect to the total mass of the molded body from the viewpoint of suppressing the detachment of powder from the molded body, and the thermal conductivity is It is preferable that it is 50 mass% or less from a viewpoint of setting it as 0.05 W / m * K or less.

  From the viewpoint of easy mixing with silica particles and infrared opaque particles, the content of inorganic fibers is more preferably 0.2% by mass or more and 40% by mass or less, and 0.2% from the viewpoint of reducing the bulk density. More preferably, it is at least 20% by mass.

[1-3] Infrared opacifying particles It is preferable that the molded body contains infrared opacifying particles when heat insulation performance at a high temperature is required. The infrared opaque particles refer to particles made of a material that reflects, scatters, or absorbs infrared rays. When the infrared opaque particles are mixed in the molded body, heat transfer due to radiation is suppressed, so that the heat insulating performance is particularly high in a high temperature range of 200 ° C. or higher.

  Examples of infrared opaque particles include zirconium oxide, zirconium silicate, titanium dioxide, iron titanium oxide, iron oxide, copper oxide, silicon carbide, gold ore, chromium dioxide, manganese dioxide, graphite and other carbonaceous materials, carbon fibers , Spinel pigments, aluminum particles, stainless steel particles, bronze particles, copper / zinc alloy particles, and copper / chromium alloy particles. Conventionally, the above metal particles or nonmetal particles known as infrared opaque materials may be used alone or in combination of two or more.

  As the infrared opaque particles, zirconium oxide, zirconium silicate, titanium dioxide or silicon carbide is particularly preferable. The composition of the infrared opaque particles is determined by FE-SEM EDX.

  The average particle diameter of the infrared opaque particles is preferably 0.5 μm or more from the viewpoint of heat insulation performance at 200 ° C. or more, and preferably 30 μm or less from the viewpoint of heat insulation performance at less than 200 ° C. due to suppression of solid conduction. The average particle size of the infrared opaque particles is determined by the same method as that for silica particles. Depending on the size of the inorganic fibers and silica particles, when the silica particles are 5 nm to 50 μm, the average particle diameter of the infrared opaque particles is 0.5 μm or more and 10 μm or less from the viewpoint of easy mixing with the silica particles. It is more preferable.

  The content of the infrared opaque particles in the molded body is preferably 0.1% by mass or more and 39.5% by mass or less. If the content of the infrared opaque particles is larger than 39.5% by mass, heat transfer by solid conduction is large, so that the heat insulation performance at less than 200 ° C. tends to be low. In order to improve the heat insulation performance at 200 ° C. or higher, the content of the infrared opaque particles is more preferably 0.5% by mass or more and 35% by mass or less, and further preferably 1% by mass or more and 30% by mass or less. When a powder containing silica and infrared opacifying particles is prepared, an element contained only in the infrared opacifying particles in the powder is prepared by fluorescent X-ray analysis (XRF). By analyzing or analyzing the crystal structure contained only in the infrared opaque particles by powder X-ray diffraction (XRD), it can be used as an index for quality control of the powder mixed state. Some infrared opaque particles are colored black or the like, but if the infrared opaque particles are colored, there is also an effect that the mixing condition can be confirmed visually.

  The content of the infrared opacifying particles can be determined, for example, by measuring the composition of the infrared opacifying particles with FE-SEM EDX and quantifying the elements contained only in the infrared opacifying particles by fluorescent X-ray analysis. it can.

[1-4] cumulative pore volume compacts, the ratio _{R 0.1} of the cumulative pore volume _{V 0.1} pore pore diameter is 0.1μm or more 150μm or less, the pore diameter is more than 0.003μm It is 50% or more and 85% or less with respect to the cumulative pore volume V _0.003 of the pores of 150 μm or less, and V _0.1 is 0.2 mL / g or more and 3 mL / g or less. The integrated pore volume is defined by a value measured by a mercury intrusion method described later. If R _0.1 is less than 50%, molding defects tend to occur, and if it exceeds 85%, the heat insulation performance tends to be low. V _0.1 tends insulation performance is low, less than 0.2 mL / g, molding defects to be 3 mL / g greater tends to easily occur. At this time, V _0.003 is preferably 0.5 mL / g or more and 3.8 mL / g or less.

The reason for this is not clear, but the molded body has pore diameters of 0.1 μm or more in the above ratio, and the accumulated pore volume in the above range makes it easy for air taken in between the particles to escape, As a result, the present inventor estimates that springback and lamination are suppressed. From the viewpoint of suppressing molding defects and dimensional changes of the molded body, R _0.1 is preferably 50% or more and 80% or less, more preferably 52% or more and 78% or less, based on the total pore volume of the molded body, 54 % To 76% is more preferable. V _0.1 is preferably less 0.25 mL / g or more 2.8 mL / g, more preferably at most 0.25 mL / g or more 2.6 mL / g, or less 0.25 mL / g or more 2.4 mL / g Further preferred. V _0.003 is preferably 0.5 mL / g or more and 3.8 mL / g or less, more preferably 0.5 mL / g or more and 3.5 mL / g or less, and 0.6 mL / g or more and 3.0 mL / g. The following is more preferable.

[1-5] Thermal conductivity The molded body has a thermal conductivity at 30 ° C. of 0.05 W / m · K or less. From the viewpoint of heat insulation performance, the thermal conductivity is preferably 0.045 W / m · K or less, more preferably 0.040 W / m · K or less, and even more preferably 0.037 W / m · K or less. When the molded body contains infrared opaque particles, the thermal conductivity at 800 ° C. is preferably 0.15 W / m · K or less, more preferably 0.14 W / m · K or less, and More preferably, it is 13 W / m · K or less. A method for measuring the thermal conductivity will be described later.

  When mixing inorganic fibers and infrared opacifying particles, if the mixing amount is excessive, the heat insulating property may be lowered. Therefore, it is preferable to appropriately prepare while measuring and confirming the thermal conductivity. For example, when inorganic fibers having an average fiber diameter of 12 μm and an average length of 5 mm are mixed with silica, the mixing amount of the inorganic fibers is preferably 30% by mass or less. For example, when infrared opaque particles having an average particle diameter of 2 μm are mixed with silica, the amount of infrared opaque particles to be mixed is preferably 23% by mass or less. Further, when inorganic fibers or infrared opaque particles made of a material having a low thermal conductivity are selected and used, a molded product having a thermal conductivity of 0.05 W / m · K or less tends to be obtained.

[1-6] Content of Na, Ge, Fe The molded body contains Na based on the total mass of the molded body from the viewpoint of increasing the adhesion between particles and reducing the detachment of particles from the molded body. The amount is preferably 0.005 mass% or more and 3 mass% or less, more preferably 0.005 mass% or more and 2 mass% or less, and 0.005 mass% or more and 1.5 mass% or less. Is more preferable. Similarly, the Ge content is preferably 10 ppm or more and 1000 ppm or less, more preferably 20 ppm or more and 900 ppm or less, and further preferably 20 ppm or more and 800 ppm or less. Similarly, the Fe content is preferably 0.005% by mass to 6% by mass, more preferably 0.005% by mass to 3% by mass, and 0.005% by mass to 2%. More preferably, it is at most mass%. The contents of Na, Ge, and Fe in the molded body can be quantified by XRF (fluorescence X-ray analysis). The molded body may contain aluminum (Al), phosphorus (P), sulfur (S), chlorine (Cl), and nickel (Ni) as impurities.

[2] The method for producing a molded article of the manufacturing method embodiment of the shaped body comprises silica, and small particles having an average particle diameter _{D S} is at 5nm or 30nm or less, comprises silica, average particle diameter _{D L} is 40nm The step of mixing the large particles having a particle size of 60 μm or less to obtain an inorganic mixture, and the step of molding the inorganic mixture so that the bulk density of the molded body is 0.25 g / cm ³ or more and 2.0 g / cm ³ or less. And having.

[2-1] Silica particles Specific examples of the silica particles include the following.
An oxide of silicon called “silica” or “quartz”.
Partial oxide of silicon.
Silicon complex oxide such as silica alumina and zeolite.
Any one of silicate (glass) of Na, Ca, K, Mg, Ba, Ce, B, Fe and Al.
A mixture of an oxide, partial oxide, salt or composite oxide (alumina, titania, etc.) of an element other than silicon and an oxide, partial oxide, salt or composite oxide of silicon.
SiC and SiN oxides.

  When using a molded object as a heat insulating material, the silica particles are preferably thermally stable at the temperature used. Specifically, it is preferable that the weight of the silica particles does not decrease by 10% or more when held for 1 hour at the maximum use temperature of the heat insulating material. The silica particles preferably have water resistance. Specifically, the amount of silica particles dissolved in 100 g of water at 25 ° C. is preferably less than 0.1 g, and more preferably less than 0.01 g.

  The specific gravity of the silica particles is preferably 2.0 or more and 4.0 or less when the molded body is a heat insulating material. It is more preferable that it is 2.0 or more and 3.0 or less because the bulk density of the molded body is small, and it is more preferable that it is 2.0 or more and 2.5 or less. Here, the specific gravity of the silica particles refers to the true specific gravity determined by the pycnometer method.

  The molded body may contain only one kind of silica particles, or may contain two or more kinds. In particular, it is preferable to contain two kinds of particles having different particle diameters, for example, small particles and large particles made of silica, because the thermal conductivity and the integrated pore volume can be easily adjusted. As described above, it is known that a porous body having voids with a diameter of 100 nm or less has a low thermal conductivity and is suitable for a heat insulating material. When it is desired to obtain such a molded body, it is simple to form ultrafine particles having a particle diameter of 100 nm or less by pressing or the like. On the other hand, it was conventionally regarded as unsuitable as a heat insulating material, for example, even if a particle having a particle size not so small on the order of micrometers is used as a raw material, it is excellent by mixing with ultrafine particles in an appropriate amount. It has been found that it is possible to develop the heat insulation performance.

For example, in the present embodiment, two kinds of particles having different particle diameters, i.e. the shaped body comprising large particles and small particles in the raw material, the average particle diameter D _S of the small particles is 5nm or more 30nm or less. If D _S is in 5nm or more, compared to the case D _S is outside the above numerical range, they tend small particles are chemically stable, heat-insulating performance may stable tendency. If D _S is a 30nm or less, compared with the case D _S is outside the above numerical range, small contact area between the small particles, less heat transfer by solid conduction molded body tends low thermal conductivity There is.

D _S is, if it is 5nm or 25nm or less, from the viewpoint of reducing the thermal conductivity, and more preferably a 5nm or 15nm or less.

In the present embodiment, the average particle diameter D _L of the large particles satisfies D _S <D _L and is 40 nm or more and 60 μm or less. D _L is obtained by the same method as D _S described above. When _DL is 40 nm or more, the spring back in the molded product tends to be small. When D _L is at 60μm or less, presents a tendency low thermal _{conductivity,} the _{R 0.1,} there is prone to 85% more than 50% or less based on the total pore volume of the shaped body.

The average particle diameter D _L of the larger particles, if it is 40nm or more 10μm or less, when the molded body containing the inorganic fibers and the infrared opacifying particles, uniform mixing of these in the preparation of an inorganic mixture which is the raw material of the molded body Is preferable because it is easy. D _L is, if it is 40nm or more 5μm or less, increase adhesion of the particles, for separation of particles from the inorganic mixture is small, which is a raw material of the molded body, and more preferred.

When D _L is at least twice the D _S, because the spring back of the molded body is reduced, preferably. D _L is the is more than three times D _S, large bulk specific gravity of the molded article comprising the small particles and large particles, due to its high workability and compact volume is small, more preferred. D _L is the is more than 4 times the D _S, large difference in particle size of the small particles and large particles, since it is easy to disperse for small particles of large particles when mixed with small particles and large particles, further preferable. When the molded body is used for a heat insulating material, each particle is preferably dispersed from the viewpoint of solid heat transfer due to aggregation of the particles.

When preparing an inorganic mixture by mixing a plurality of types of silica particles, for example, small particles and large particles as described above, and then preparing a molded product, the thermal conductivity and fineness of the molded product composed of each particle are obtained. When the pore volume is measured by a mercury intrusion method and mixing is performed assuming that additivity is established, R _0.1 is 50% or more and 85% or less with respect to the total pore volume of the molded body, and V _{0. 1} is 0.2 mL / g or more and 3 mL / g or less, V _0.003 / V _0.1 is larger than 1, and the thermal conductivity at 30 ° C. tends to be 0.05 W / m · K or less. There is. When it is difficult to produce a molded body only with each particle and raw material, including inorganic fibers and infrared opaque particles, measurement is performed without producing a molded body, and additivity is established as described above. Assuming that the amount of mixing is easy to adjust, but there are cases where it may deviate greatly from additivity, so the amount of raw material is estimated based on the thermal conductivity and pore volume of each raw material, and the inorganic mixture is adjusted. It is preferable to adjust the mixing amount as appropriate while measuring the thermal conductivity and the accumulated pore volume of the formed body.

  The molded body preferably contains a water repellent from the viewpoint of suppressing deterioration of handling properties, deformation of the molded body, cracking, and the like when water penetrates into the molded body. Examples of the water repellent include wax-based water repellents such as paraffin wax, polyethylene wax, and acrylic / ethylene copolymer wax; silicon-based water repellents such as silicon resin, polydimethylsiloxane, and alkylalkoxysilane; Fluorine-based water repellents such as carboxylates, perfluoroalkyl phosphates, perfluoroalkyltrimethylammonium salts, silane coupling agents such as alkoxysilanes containing alkyl or perfluoro groups, trimethylsilyl chloride, 1,1,1 And silylating agents such as 3,3,3-hexamethyldisilazane. These can be used alone or in combination of two or more. These may be used as they are, or in the form of a solution or an emulsion. It is also possible to apply the water repellent as it is or in the form of a solution or an emulsion to the molded body. Although the method of apply | coating is not specifically limited, For example, brush coating, roller coating, spraying, spraying, airless spray, roll coater, and immersion are mentioned. A water repellent effect can also be obtained when a water repellent is added to the powder as a raw material of the molded body and a molded body is produced using the water-repellent treated powder. The method of adding the water repellent to the powder is not particularly limited. For example, a method in which the powder is stirred and dried while adding a solution obtained by diluting these water repellents with a solvent such as water or alcohol. Examples include a method of dispersing in a solvent such as water or alcohol to form a slurry, adding a water repellent thereto, stirring and filtering, and drying, and steaming with chlorotrimethylsilane. Of these, wax-based water repellents and silicon-based water repellents are preferably used in the present embodiment. The content of the water repellent in the inorganic mixture is preferably 100/30 to 100 / 0.1, and the mass ratio of the whole inorganic mixture / the water repellent is preferably 100/30, from the viewpoint of imparting a sufficient water repellent effect. 20-100 / 0.5 is more preferable, and 100 / 10-100 / 1 is still more preferable.

  As silica particles, particles having a silica component produced by a conventional production method can be used as raw materials, and the sodium content and thermal conductivity can be adjusted. For example, the silica particles may be particles produced by condensing silicate ions by a wet method under acidic or alkaline conditions. The inorganic compound particles containing silica may be produced by hydrolyzing and condensing alkoxysilane by a wet method. The silica particles may be produced by firing a silica component produced by a wet method. The inorganic compound particles containing silica may be produced by burning a silicon compound such as chloride in the gas phase. The silica particles may be produced by oxidizing and burning silicon gas obtained by heating a raw material containing silicon metal or silicon. The silica particles may be produced by melting silica or the like.

  As components other than the silica component contained in the silica particles, those present as impurities in the raw material in the above production method may be used. Components other than the silica component may be added during the silica production process.

  Known methods for producing silica include the following.

<Silica synthesized by wet method>
Gel silica made from sodium silicate and made acidic.
Precipitated silica made from sodium silicate and made alkaline.
Silica synthesized by hydrolysis and condensation of alkoxysilanes.

<Silica synthesized by dry method>
Fumed silica made by burning silicon chloride.
Silica produced by burning silicon metal gas.
Silica fume by-produced during ferrosilicon production.
Silica produced by the arc method or plasma method.
Fused silica made by melting silica.

  When preparing the raw material of a molded object by mixing two or more types of silica particles, for example, small particles and large particles, it is more preferable to use fumed silica as the small particles among the above silicas. As the large particles, fumed silica, silica produced by burning silicon metal gas, silica fume, or fused silica is more preferably used.

It is possible to use natural silicate minerals as inorganic compound particles containing silica. Examples of natural minerals include olivine, chlorite, quartz, feldspar, zeolite and the like. The natural particle silicate mineral is subjected to a treatment such as pulverization to adjust the average particle diameter, and can be used as silica particles constituting the molded body. When R _0.1 or V _0.1 does not satisfy the above-described range, a plurality of silica particles can be mixed and used as a raw material for a molded body by a method described later.

[2-2] Na, Ge, Fe
Na, Ge, and Fe may be added as a compound containing Na, Ge, and Fe, respectively, during the silica manufacturing process and the inorganic mixture manufacturing process, but contain sufficient amounts of Na, Ge, and Fe in advance. Inorganic compound particles containing silica may be used. Although it does not specifically limit as a compound containing Na, Ge, and Fe, For example, the oxide of Na, Ge, Fe, complex oxide, hydroxide, nitride, carbide, carbonate, acetate, nitrate, sparingly soluble Examples thereof include salts and alkoxides. These may be added alone or a mixture thereof may be added. Using inorganic compound particles containing silica containing Na, Ge, and Fe as impurities as a raw material of the inorganic mixture is a preferable embodiment from the viewpoint of productivity, cost, and workability. Such inorganic compound particles containing silica can be obtained, for example, as silica fume that replicates during the production of silica gel-derived particles or ferrosilicon produced by a precipitation method.

  The method for adding a compound containing Na, Ge, and Fe is not particularly limited. For example, you may add to the silica obtained by the said wet method or the dry method, and may add in each said manufacturing process of a silica. The compound containing each of Na, Ge, and Fe may be water-soluble or insoluble in water. It may be added as an aqueous solution of a compound containing Na, Ge, and Fe, respectively, and may be dried as necessary, or a compound containing Na, Ge, and Fe may be added in a solid or liquid state. The compound containing each of Na, Ge, and Fe may be pulverized to a predetermined particle diameter in advance, or may be preliminarily coarsely pulverized.

  If the silica particles contain an excessive amount of Na, Ge, Fe, even if some processing is performed during the silica production process or the molding production process, the content of the element is adjusted to a predetermined range. Good. A method for adjusting an excessive amount of Na, Ge, and Fe to a predetermined range is not particularly limited. For example, the method for adjusting the content of Na includes substitution, extraction, removal methods, etc. with an acidic substance or other elements. The inorganic compound particles containing silica are treated with nitric acid or aqua regia, and then dried. It can be used as a raw material of a molded body. Adjustment of an excessive amount of Na, Ge, and Fe may be performed after previously pulverizing silica particles to a desired particle diameter, or after adjusting Na, Ge, and Fe to a predetermined range, the silica particles may be pulverized. It doesn't matter.

[2-3] Mixing method Silica particles, infrared opaque particles and inorganic fibers should be mixed using a known powder mixer, for example, those listed in the revised sixth edition Chemical Engineering Handbook (Maruzen). Can do. At this time, it is possible to mix two or more kinds of inorganic compound particles containing silica, or a compound containing Na, K, Mg, Ca, Fe, P, and S or an aqueous solution thereof. Known powder mixers include a horizontal cylindrical type, a V type (which may be equipped with a stirring blade), a double cone type, a cubic type, and a shaking type as a container rotating type (the container itself rotates, vibrates and swings). Dynamic rotation type, mechanical agitation type (container is fixed and agitated with blades), single axis ribbon type, double axis paddle type, rotary saddle type, biaxial planetary agitation type, conical screw type, high speed agitation type, rotation Examples of the disk type, the rotating container type with roller, the rotating container type with stirring, the high-speed elliptical rotor type, and the fluid stirring type (stirring by air and gas) include an airflow stirring type and a non-stirring type by gravity. You may use combining these mixers.

  Mixing of silica particles, infrared opacifying particles and inorganic fibers is known as a pulverizer, such as those listed in the revised 6th edition, Chemical Engineering Handbook (Maruzen). You may carry out, cutting a fiber or improving the dispersibility of particle | grains and an inorganic fiber. At this time, it is also possible to pulverize and disperse two or more kinds of inorganic compound particles containing silica, or pulverize and disperse a compound containing Na, K, Mg, Ca, Fe, P, and S or an aqueous solution thereof. is there. Known mills include roll mills (high-pressure compression roll mills, roll rotating mills), stamp mills, edge runners (fret mills, Chillian mills), cutting / shear mills (cutter mills, etc.), rod mills, self-pulverizing mills (erofall mills, Cascade mills), vertical roller mills (ring roller mills, rollerless mills, ball race mills), high-speed rotary mills (hammer mills, cage mills, disintegrators, screen mills, disc pin mills), high-speed rotary mills with built-in classifiers (fixed) Impact plate mill, turbo mill, centrifugal classification mill, annular mill, container drive media mill (rolling ball mill (pot mill, tube mill, conical mill)), vibration ball mill (circular vibration mill, rotational vibration mill, centrifugal mill) ), Planetary mill, centrifugal fluidization mill), medium Stirring mill (tower crusher, stirring tank mill, horizontal flow tank mill, vertical flow tank mill, annular mill), airflow grinder (airflow suction type, nozzle passage type, collision type, fluidized bed) Jet blow type), compaction shear mill (high-speed centrifugal roller mill, inner piece type), mortar, stone mill and the like. You may use combining these grinders.

  Among these mixers and pulverizers, powder mixers with stirring blades, high-speed rotary mills, high-speed rotary mills with built-in classifiers, container drive medium mills, and compaction shear mills improve the dispersibility of particles and inorganic fibers. Therefore, it is preferable. In order to improve the dispersibility of the particles and inorganic fibers, it is preferable to set the peripheral speed of the tip of the stirring blade, rotating plate, hammer plate, blade, pin, etc. to 100 km / h or more, more preferably 200 km / h or more, More preferably, it is 300 km / h or more.

  When mixing a plurality of types of silica particles, it is preferable to introduce the silica particles into a stirrer or a pulverizer in order of increasing bulk specific gravity. In the case where inorganic fibers or infrared opaque particles are included, it is preferable to add and mix infrared opaque particles after mixing silica particles, and then add and mix inorganic fibers.

[2-4] Molding method A molded body can be obtained by pressure-molding an inorganic mixture as a raw material. As the pressure molding method, molding may be performed by a conventionally known ceramic pressure molding method such as a die press molding method (ram type pressure molding method), a rubber press method (hydrostatic pressure molding method), or an extrusion molding method. it can. From the viewpoint of productivity, a die press molding method is preferable.

When filling the mold with an inorganic mixture in the mold press molding method or the rubber press method, the thickness of the molded body becomes uniform by uniformly filling the mold by, for example, applying vibration to the inorganic mixture that is the raw material of the molded body. Therefore, it is preferable. Filling the mold with the inorganic mixture while decompressing and degassing the inside of the mold is preferable from the viewpoint of productivity because it can be filled in a short time. When trying to control the molding conditions with pressurized pressure, with the passage of time to hold in the pressurized state due to the slipperiness of the powder used, the amount of air taken in between the powder particles and into the pores, etc. Because the pressure value changes, production management tends to be difficult. On the other hand, the method of controlling the bulk density is preferable in that the load of the molded body obtained without requiring time control can be easily set to the target value. Incidentally, in the molding method of the present embodiment, the bulk density of the molded body is a ^{0.25g / cm 3 ~2.0g / cm 3} , 0.25g / cm 3 from the viewpoint of reducing the burden during transportation ˜1.7 g / cm ³ is preferable, and 0.25 g / cm ^{3 to} 1.5 g / cm ³ is more preferable.

An example of a method for producing a molded body will be described so that the bulk density of the obtained molded body has a predetermined size. First, the weight of the necessary inorganic mixture is obtained from the volume and bulk density of the molded body. Next, the weighed inorganic mixture is filled in a mold and pressed to a predetermined thickness and molded. Specifically, in the case of producing a molded body having a length of 30 cm, a width of 30 cm, a thickness of 20 mm and a bulk density of 0.5 g / cm ³ , the molded body is multiplied by the volume of the molded body to be manufactured to the target bulk density. It is possible to determine the weight of the powder necessary for the production. That is, in the example of the molded body described above, 0.5 [g / cm ³ ] × 30 [cm] × 30 [cm] × 2 [cm] = 900 [g], and necessary powder is 900 g.
In general, when producing a molded body having a volume αcm ³ and a bulk density of βg / cm ³ (where β is larger than the bulk density of the powder), the powder is weighed by αβg and the powder is made up to the volume α. Form by compressing the body.

  When the molded body during or after pressure molding is subjected to heat drying within the range of temperature and time conditions where the molded body has sufficient heat resistance, and after removing adsorbed water from the molded body, it is put into practical use. The thermal conductivity is preferably low. Furthermore, you may heat-process.

  From the viewpoint of dimensional stability, the heat treatment temperature is preferably higher than the maximum use temperature of the molded body. Although it changes with uses of a molded object, specifically 400-1200 degreeC is preferable, More preferably, it is 500-1200 degreeC, More preferably, it is 600-1200 degreeC.

  The atmosphere of the heat treatment of the molded body is in the air (or in the air), in an oxidizing atmosphere (oxygen, ozone, nitrogen oxide, carbon dioxide, hydrogen peroxide, hypochlorous acid, inorganic / organic peroxide, etc.) And in an inert gas atmosphere (helium, argon, nitrogen, etc.). The heat treatment time may be appropriately selected according to the heat treatment temperature and the amount of the heat insulating material. The heat treatment may be performed after being installed at a location where the molded body is used, or may be installed at a location where the molded body is used after being heated.

[3] Encapsulant The encapsulant includes an outer covering material and a molded body accommodated in the outer covering material. The encapsulated body has the advantage that it is easier to handle and easier to construct than the molded body. FIG. 1 is a schematic cross-sectional view of an enveloping body according to the present embodiment. FIG. 2 is a schematic cross-sectional view of small particles and large particles contained in the molded product according to this embodiment. As shown in FIG.1 and FIG.2, the envelope 1 of this embodiment is a molded body 2 containing a plurality of small particles S and a plurality of large particles L having a particle diameter larger than that of the small particles S. The outer casing 3 is configured to accommodate the molded body 2. In the molded body 2, the small particles S and the large particles L are mixed, and the small particles S exist around the large particles L. Such a molded body 2 may be referred to as a core material.

[3-1] Cover Material The cover material is not particularly limited as long as it can accommodate a molded body as a core material. Examples thereof include inorganic fiber fabrics such as glass cloth, alumina fiber cloth, and silica cloth, and inorganic fibers. Knitted fabric, polyester film, polyethylene film, polypropylene film, nylon film, polyethylene terephthalate film, resin film such as fluororesin film, plastic-metal film, metal foil such as aluminum foil, stainless steel foil, copper foil, ceramic paper, inorganic fiber Nonwoven fabric, organic fiber nonwoven fabric, glass fiber paper, carbon fiber paper, rock wool paper, inorganic filler paper, organic fiber paper, ceramic coating, fluororesin coating, siloxane resin coating, and other resin coatings can be exemplified. When the encapsulant is a heat insulating material, it is preferable that the thickness of the outer covering material is thin from the viewpoint of reducing the heat capacity of the outer covering material, but it can be appropriately selected according to the use situation, required strength, etc. is there. When the jacket material is made of a material that is stable at the temperature at which the core material is used, the jacket material is in a state of containing an inorganic mixture or molded body that is the core material even during use. In the case of an envelope to be used at a high temperature, a highly heat-resistant outer covering material is preferable from the viewpoint of easy handling of the core material after use. In addition to what contains the core material at the time of use, the thing which accommodates the core material in the process of conveyance and construction of the core material is included. In other words, the jacket material protects the core material only during transportation and construction, and includes those that melt and / or volatilize during use, so that the organic material contained in the jacket material itself or the jacket material is the core. It may melt or disappear at the use temperature of the material.

  From the viewpoint that the coating process is easy, inorganic fiber fabrics such as glass cloth, alumina fiber cloth, silica cloth, inorganic fiber knitted fabric, polyester film, polyethylene film, polypropylene film, nylon film, polyethylene terephthalate film, fluorine Resin film such as plastic resin film, plastic-metal film, aluminum foil, stainless steel foil, metal foil such as copper foil, ceramic paper, inorganic fiber nonwoven fabric, organic fiber nonwoven fabric, glass fiber paper, carbon fiber paper, rock wool paper, inorganic Sheet shapes such as filled paper and organic fiber paper are preferred.

  When the enveloping body is used at high temperature, the covering material is made of inorganic fiber woven fabric such as glass cloth, alumina fiber cloth, silica cloth, inorganic fiber knitted fabric, ceramic paper, inorganic fiber non-woven fabric from the viewpoint of thermal stability. Is more preferable. The jacket material is more preferably an inorganic fiber fabric from the viewpoint of strength.

[3-2] Method of coating with outer jacket material The molded body contains silica particles, and an inorganic mixture formed by adding large particles, infrared opaque particles and inorganic fibers according to the use situation is used as a raw material. The core material may be formed by pressure molding and coated with a jacket material. When the molded body is used as the core material, as described later, the inorganic mixture that is the raw material of the molded body and the jacket material may be pressure-molded together, or after the inorganic mixture is pressure-molded, It is also possible to coat.

  The method of coating the core material with the jacket material is not particularly limited, and the core material may be prepared or molded and coated with the jacket material at the same time, or the core material may be coated with the jacket material after preparation or molding. May be.

  Cover material is inorganic fiber fabric, resin film, plastic-metal film, metal foil, ceramic paper, inorganic fiber nonwoven fabric, organic fiber nonwoven fabric, glass fiber paper, carbon fiber paper, rock wool paper, inorganic filler paper, organic fiber paper, etc. In the case of the sheet-like form, for example, it is possible to cover with stitching with inorganic fiber yarn or resin fiber yarn, adhesion fixing of the jacket material, and both stitching and adhesion.

  When the sheet-like outer covering material is a resin film, a plastic-metal film, a metal foil or the like, a vacuum pack or a shrink pack is preferable from the viewpoint of ease of the coating process.

  When the jacket material is ceramic coating, resin coating, or the like, the core material can be covered with the jacket material by applying the core material with a brush or spray.

  It is also possible to provide linear recesses in a molded body composed of a pressure-molded core material and a jacket material, thereby imparting flexibility to the molded body. The form of the line can be selected from a straight line shape, a curved line shape, a broken line shape and the like according to the usage state of the molded body, and two or more of these may be combined. The thickness of the line and the depth of the dent are determined according to the thickness, strength, and usage of the molded body.

  The jacket material may cover the entire surface of the core material, or may partially cover the core material.

[4] Applications The molded body and the envelope of the present embodiment include a heat absorbing material, a sound absorbing material, a sound insulating material, a sound insulating material, an anti-reflection material, a sound deadening material, an abrasive, a catalyst carrier, an adsorbent, an fragrance, and a sterilizer It can also be suitably used for carriers that adsorb drugs such as agents, deodorizers, deodorants, humidity control materials, fillers, pigments, and the like.

[5] Measurement of parameters Measurement of the cumulative pore volume, thermal conductivity, and springback of the inorganic mixture are carried out by the following methods.

[Measurement of integrated pore volume]
The pore distribution measuring device is measured by mercury porosimetry using Autopore 9520 type (manufactured by Shimadzu Corporation). The molded body is cut into a rectangular parallelepiped so as to enter the cell, one is taken into a low-sensitivity cell, and the pressure is measured under conditions of an initial pressure of about 7 kPa (about 1 psia, pore diameter of about 180 μm). The mercury parameters are set at the instrument default mercury contact angle of 130 degrees and the mercury surface tension of 485 dynes / cm.

[Measurement of thermal conductivity]
A molded body having a shape of 30 cm in length, 30 cm in width, and 20 mm in thickness is used as a measurement sample, and heat conductivity at 30 ° C. is measured using a heat flow meter HFM 436 Lambda (trade name, manufactured by NETZSCH). taking measurement. Calibration is performed according to JIS A1412-2 using a NIST SRM 1450c calibration standard plate having a density of 163.12 kg / m ³ and a thickness of 25.32 mm under the condition that the temperature difference between the high temperature side and the low temperature side is 20 ° C. 20, 24, 30, 40, 50, 60, and 65 ° C. in advance. The thermal conductivity at 800 ° C. is measured according to the method of JIS A 1422-1. Two compacts having a disk shape of 30 cm in diameter and 20 mm in thickness are used as measurement samples, and a protective hot plate method thermal conductivity measuring device (manufactured by Eiko Seiki Co., Ltd.) is used as a measuring device.

[Measurement of springback]
Fix the horizontal dimension of the inorganic mixture that is the raw material of the molded body (including the above-mentioned small particles and large particles, and if necessary, the entire mixed powder including infrared opaque particles and inorganic fibers), and then mix the inorganic mixture. in a state where pressure is applied so as to obtain a molded body having a predetermined bulk density, the thickness in the vertical direction of the inorganic mixture (molding material) and T ₁ in a direction perpendicular to, after pressurization, molded in the horizontal direction while fixing the size of the body, when the thickness in the vertical direction of the molded body after the pressure was released and the T _2, T ₂ -T ₁ of ratio T _1, i.e. the rate of increase in thickness of the molded body 100 (T evaluate by measuring _{2 -T 1) / T 1 [} %]. Note that “fixing the dimension in the horizontal direction” means, for example, a state in which a square or cylindrical frame-shaped mold is filled with an inorganic mixture that is a raw material of a molded body.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to these Examples. Those skilled in the art can implement various modifications as well as the following embodiments, and such modifications are also included in the scope of the claims of the present invention. In the examples and comparative examples, the measurement of the integrated pore volume, the measurement of thermal conductivity, and the measurement of spring back of the molded bodies were as described above.

[Example 1]
A silica powder in which 25 mass% of silica powder having an average particle diameter of 12 nm and 75 mass% of silica powder having an average particle diameter of 80 nm were uniformly mixed using a hammer mill was obtained. An example in which 792 g of this silica powder is used to perform pressure molding with a mold having an internal dimension of 30 cm in length and 30 cm in width, and 30 cm in length, 30 cm in width, 20 mm in thickness, and a bulk density of 0.44 g / cm ^3. 1 molded body was obtained. In the molded body of Example 1, springback and lamination were suppressed, and no molding defects were observed. At this time, the increasing rate of the thickness of the molded body was 105%. When the integrated pore volume of this molded article was measured, _R0.1 was 79%, _V0.1 was 1.5 mL / g, and _V0.003 was 1.9 mL / g. Moreover, the heat conductivity in 30 degreeC was 0.0266 W / m * K.

[Example 2]
A silica powder in which 90% by mass of silica powder having an average particle size of 7.5 nm and 10% by mass of silica powder having an average particle size of 60 μm were uniformly mixed using a hammer mill was obtained. Using this 421 g of silica powder, pressure molding is performed in the same mold as in Example 1, and the molded body of Example 2 having a length of 30 cm, a width of 30 cm, a thickness of 20 mm, and a bulk density of 0.23 g / cm ^3. Got. In the molded body of Example 2, springback and lamination were suppressed, and no molding defects were observed. At this time, the increasing rate of the thickness of the molded body was 107%. Measurement of the cumulative pore volume of the shaped _{body, R 0.1} is _{68%, V 0.1} is 2.6mL _{/ g, V 0.003} was 3.8 mL / g. The heat conductivity at 30 ° C. was 0.0205 W / m · K.

[Example 3]
A silica powder in which 25% by mass of silica powder having an average particle size of 14 nm and 75% by mass of silica powder having an average particle size of 150 nm were uniformly mixed using a hammer mill was obtained. Using this silica powder 900 g, pressure molding is performed in the same mold as in Example 1, and the molded body of Example 3 having a length of 30 cm, a width of 30 cm, a thickness of 20 mm, and a bulk density of 0.5 g / cm ^3. Got. In the molded body of Example 3, springback and lamination were suppressed, and no molding defects were observed. The increasing rate of the thickness of the molded body at this time was 103%. Measurement of the cumulative pore volume of the shaped _{body, R 0.1} is _{53%, V 0.1} is 0.8mL _{/ g, V 0.003} was 1.5 mL / g. The heat conductivity at 30 ° C. was 0.0264 W / m · K.

[Example 4]
A silica powder in which 50% by mass of silica powder having an average particle size of 7.5 nm and 50% by mass of silica powder having an average particle size of 80 nm were uniformly mixed using a hammer mill was obtained. Using this 594 g of silica powder, pressure molding was performed in the same mold as in Example 1, and the molded body of Example 4 having a length of 30 cm, a width of 30 cm, a thickness of 20 mm, and a bulk density of 0.33 g / cm ^3. Got. In the molded body of Example 4, springback and lamination were suppressed, and no molding defects were observed. At this time, the increasing rate of the thickness of the molded body was 104%. Measurement of the cumulative pore volume of the shaped _{body, R 0.1} is _{67%, V 0.1} is 1.8mL _{/ g, V 0.003} was 2.7 mL / g. Moreover, the heat conductivity in 30 degreeC was 0.0198 W / m * K.

[Example 5]
An infrared opaque particle having an average particle diameter of 1 μm after uniformly mixing 21 mass% of silica powder with an average particle diameter of 14 nm and 63 mass% of silica powder with an average particle diameter of 150 nm using a hammer mill. Then, 16% by mass of zirconium silicate was added and mixed uniformly to obtain silica powder. Using this silica powder 1042 g, pressure molding is performed in the same mold as in Example 1, and the molded body of Example 5 is 30 cm long, 30 cm wide, 20 mm thick, and has a bulk density of 0.58 g / cm ^3. Got. In the molded body of Example 5, springback and lamination were suppressed, and molding defects were not observed. At this time, the rate of increase in the thickness of the molded body was 102%. Measurement of the cumulative pore volume of the shaped _{body, R 0.1} is _{59%, V 0.1} was 1.0mL _{/ g, V 0.003} is 1.7 mL / g. Moreover, the heat conductivity in 30 degreeC was 0.0275 W / m * K. Further, 819 g of the above silica powder was used, and pressure molding was performed using a cylindrical mold having an inner diameter of 30 cm to obtain two disk-shaped molded bodies having a diameter of 30 cm and a thickness of 20 mm. . When the heat conductivity at 800 ° C. was measured using these two molded bodies, it was 0.0851 W / m · K.

[Example 6]
After uniformly mixing 22% by mass of silica powder having an average particle size of 7.5 nm and 68% by mass of silica powder having an average particle size of 80 nm using a hammer mill, the average fiber length was 11 μm and the average fiber length was 10% by mass of 6.4 mm glass fiber was added and mixed with a high-speed shear mixer to obtain a silica powder. Using this 864 g of silica powder, pressure molding is performed in the same mold as in Example 1, and the molded body of Example 6 having a length of 30 cm, a width of 30 cm, a thickness of 20 mm, and a bulk density of 0.48 g / cm ^3. Got. In the molded body of Example 6, springback and lamination were suppressed, and no molding defects were observed. The increasing rate of the thickness of the molded body at this time was 106%. Measurement of the cumulative pore volume of the shaped _{body, R 0.1} is _{61%, V 0.1} is 1.1mL _{/ g, V 0.003} was 1.8 mL / g. Moreover, the heat conductivity in 30 degreeC was 0.0263 W / m * K.

[Example 7]
Infrared opaqued particles having an average particle size of 1 μm after uniformly mixing 20% by mass of silica powder having an average particle size of 14 nm and 60% by mass of silica powder having an average particle size of 6 μm using a hammer mill Next, 15% by mass of zirconium silicate is added and mixed uniformly. Further, 5% by mass of glass fiber having an average fiber diameter of 11 μm and an average fiber length of 6.4 mm is added and mixed with a high-speed shear mixer. Uniformly, silica powder was obtained. Using this 491 g of silica powder, pressure molding was performed in the same mold as in Example 1, and the molded body of Example 7 having a length of 30 cm, a width of 30 cm, a thickness of 20 mm, and a bulk density of 0.27 g / cm ^3. Got. In the molded body of Example 7, springback and lamination were suppressed, and molding defects were not observed. At this time, the rate of increase in the thickness of the molded body was 102%. Measurement of the cumulative pore volume of the shaped _{body, R 0.1} is _{57%, V 0.1} is 0.4mL _{/ g, V 0.003} was 0.7 mL / g. Moreover, the heat conductivity in 30 degreeC was 0.0263 W / m * K.

[Comparative Example 1]
Comparison in which 331 g of silica powder having an average particle diameter of 14 nm is used and pressure-molded with the same mold as in Example 1, and the height is 30 cm, the width is 30 cm, the thickness is 20 mm, and the bulk density is 0.18 g / cm ^3. The molded body of Example 1 was obtained. In the molded body of Comparative Example 1, molding defects estimated to be caused by springback were observed. For this reason, the thermal conductivity of the molded article of Comparative Example 1 could not be evaluated. Measurement of the cumulative pore volume of the shaped _{body, R 0.1} is _{72%, V 0.1} is 3.6mL _{/ g, V 0.003} was 5.0 mL / g.

[Comparative Example 2]
Comparison in which 1978 g of silica powder having an average particle diameter of 320 nm is subjected to pressure molding using the same mold as in Example 1, and the length is 30 cm, the width is 30 cm, the thickness is 20 mm, and the bulk density is 1.1 g / cm ^3. The molded body of Example 2 was obtained. In the molded product of Comparative Example 2, molding defects estimated to be caused by lamination were observed. For this reason, the thermal conductivity of the molded article of Comparative Example 2 could not be evaluated. Measurement of the cumulative pore volume of the shaped _{body, R 0.1} is _{95%, V 0.1} is 0.58mL _{/ g, V 0.003} was 0.61 mL / g.

[Comparative Example 3]
Comparison using 1163 g of silica powder having an average particle diameter of 80 nm and press-molding with the same mold as in Example 1, 30 cm in length, 30 cm in width, 20 mm in thickness, and a bulk density of 0.65 g / cm ³ The molded body of Example 3 was obtained. In the molded body of Comparative Example 3, molding defects estimated to be caused by springback were observed. For this reason, the thermal conductivity of the molded article of Comparative Example 3 could not be evaluated. Measurement of the cumulative pore volume of the shaped _{body, R 0.1} is _{47%, V 0.1} is 0.52mL _{/ g, V 0.003} was 1.1 mL / g.

  DESCRIPTION OF SYMBOLS 1 ... Enveloping body, 2 ... Molded object, 3 ... Cover material, S ... Small particle, L ... Large particle.

Claims (12)

Comprises silica, and small particles having an average particle diameter _{D S} is at 5nm or 30nm or less, comprises silica, average particle diameter _{D L} is contained with large particles is 40nm or more 60μm or less,
Have pores,
Ratio R ₀ of cumulative pore volume V _0.1 of pores having a pore diameter of 0.1 μm or more and 150 μm or less to cumulative pore volume V _0.003 of pores having a pore diameter of _0.003 μm or more and 150 μm or less _.1 is 50% or more and 85% or less,
V _0.1 is 0.2 mL / g or more and 3 mL / g or less,
A molded article having a thermal conductivity at 30 ° C. of 0.05 W / m · K or less.   The molded object of Claim 1 which contains infrared opaque particles and whose heat conductivity in 800 degreeC is 0.15 W / m * K or less.   The infrared opaque particles have an average particle size of 0.5 μm or more and 30 μm or less, and the content of the infrared opaque particles is 0.1% by mass or more and 39.5% by mass or less based on the total mass of the molded body. The molded product according to claim 2, wherein   The molded product according to any one of claims 1 to 3, which contains sodium, and the content of the sodium is 0.005 mass% or more and 3 mass% or less based on the total mass of the molded product.   The molded object according to any one of claims 1 to 4, comprising iron, wherein the iron content is 0.005 mass% or more and 6 mass% or less based on the total mass of the molded article.   Molding as described in any one of Claims 1-5 which contains inorganic fiber and content of the said inorganic fiber is 0.1 to 50 mass% on the basis of the total mass of a molded object. body.   The molded object according to claim 6, wherein the inorganic fiber has biosolubility.   The molded body according to any one of claims 1 to 7, comprising germanium, wherein the content of the germanium is 10 ppm or more and 1000 ppm or less based on the total mass of the molded body. A jacket material;
The molded body according to any one of claims 1 to 8, which is accommodated in the jacket material,
An enveloping body comprising   The enveloping body of Claim 9 in which the said jacket material contains an inorganic fiber.   The encapsulant according to claim 9, wherein the covering material is a resin film. It is a manufacturing method of the forming object according to any one of claims 1 to 8,
It comprises silica, and small particles having an average particle diameter _{D S} is at 5nm or 30nm or less, comprises silica, and large particles having an average particle diameter _{D L} is at 40nm or more 60μm or less, were mixed, obtaining a mineral mixture And molding the inorganic mixture such that the bulk density of the molded body is 0.25 g / cm ³ or more and 2.0 g / cm ³ or less.

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