JP2013001596A - Molding, capsuled body, method for producing molding, and method of manufacturing cutting element - Google Patents

Abstract

Disclosed is a molded body, an encapsulated body, a manufacturing method of a molded body, and a manufacturing method of a cutting body, which are less likely to be collapsed or deformed during compression, can be shaped without cutting, and have heat insulation properties. provide.
SOLUTION It contains silica and germanium, the germanium content is 10 mass ppm or more and 1000 mass ppm or less, the maximum load at a compression rate of 0 to 5% is 0.7 MPa or more, and the heat conduction at 30 ° C. A molded product having a rate of 0.05 W / m · K or less.
[Selection figure] None

Description

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

  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, convection due to air and heat transfer due to conduction are suppressed, and such a porous body exhibits an excellent heat insulating action.

  It is known that a heat insulating material having a very low thermal conductivity can be obtained by the microporous structure in accordance with the principle of the heat insulating action. For example, in Non-Patent Document 1 below, fumed silica is selected as a material having low thermal conductivity, and ceramic fiber and heat resistance having a special particle size and particle size distribution as an infrared opacifier are used to reduce infrared transmission. A method is disclosed in which a functional metal oxide is blended and holes are provided so as to reduce the cross-sectional area of the heat passage.

Industrial heating Vol. 20 No. 4 New thermal insulation material “Microtherm” by Takayuki Eguchi New Energy and Industrial Technology Development Organization (Contractor) Nippon Steel Technology Information Center, 2007 Survey Results Report Research Report on Material Technology of Ceramics with Nano Porous Structure (March 2008) Moon)

  Certainly, the microporous structure contributes to reducing the heat conduction of the heat insulating material, but increasing the ratio of pores leads to reducing the strength of the heat insulating material. On the other hand, when analyzing the purpose of use of the heat insulating material, it is desirable to process it into a complicated shape depending on the application, but if the strength of the heat insulating material is not sufficient, it cannot withstand processing such as cutting, drilling, punching, etc. There is a problem. According to a study by the present inventor, when processing such as cutting, it is necessary that the load resistance at the time of 5% compression is large. Specifically, the maximum load at a compression rate of 0 to 5% is required. It was found necessary to be 0.7 MPa or more.

However, the microtherm described in Non-Patent Document 1 (trade name, manufactured by Nippon Microtherm Co., Ltd.) is a panel type with a density of 200 to 275 kg / m ³ , and the load at a compression rate of 5% is 2 kg / cm ^2. It is. Further, for the same type of insulation from the graph listed (Non-Patent Document # 1 "compression resistant FIG Microtherm"), to about 10% compressive deformation at a load of about 4.5 kg / cm ² When the inventor studied, the heat insulating material described in Non-Patent Document 1 did not have sufficient strength, and it was easy to collapse when trying to cut.

Non-Patent Document 2 describes that a microtherm is a solid or flexible plate-like molded body, and the compression strength at 5% compression is 75 to 600 kN / m ² depending on the density. In addition, since microtherm is a material whose deformation point is not clear and deformation occurs, the strength test method is described as measuring the relationship between compressive load and deformation rate.

  Non-Patent Document 2 introduces a strength measurement example (ASTM Test Method C 165) of an insulation material according to a standardized measurement standard of compressive strength of ASTM (American Society for Testing and Materials). . According to this, although the insulation is measured with a normal testing machine, it does not show a pattern that collapses with a certain stress, so it is described that a load-deformation curve is drawn and compared with a load at a certain deformation rate. Yes. As described above, when the heat insulating material is greatly compressed and deformed by the load, the heat insulating performance is likely to be deteriorated, and a gap is generated due to the compressive deformation, the strength of the portion is decreased, and the material is easily collapsed. Problems may arise.

  The present invention has been made in view of such problems of the prior art, is not easily collapsed or deformed at the time of compression, and can be shaped and processed without breaking, and has heat insulation. It aims at providing the manufacturing method of a body, a covering body, a molded object, and the manufacturing method of a cutting body.

  As a result of intensive studies to solve the above problems, the present inventor has discovered that a material including silica and germanium and exhibiting a specific compressive strength exhibits a high heat insulating property even in a heavy load application. The invention has been completed. That is, the present invention is as follows.

  The molded article of the present invention contains silica and germanium, the germanium content is 10 mass ppm or more and 1000 mass ppm or less, the maximum load at a compression rate of 0 to 5% is 0.7 MPa or more, and 30 ° C. The thermal conductivity at is 0.05 W / m · K or less.

  The molded article of the present invention further contains infrared opaque particles and preferably has a thermal conductivity at 800 ° C. of 0.2 W / m · K or less.

  The infrared opaque particles contained in the molded article of the present invention have an average particle diameter of 0.5 μm or more and 30 μm or less, and the content of the infrared opaque particles is 0.1 mass based on the mass of the molded article. % Or more and 39.5% by mass or less is preferable.

  The molded article 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.

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

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

  The enveloping body of this invention is provided with the said molded object and the outer covering material which accommodates a molded object.

  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 manufacturing method for obtaining the molded article of the present invention includes a step of heat-treating an inorganic mixture containing silica and germanium and having a germanium content of 10 mass ppm to 1000 mass ppm at a temperature of 600 ° C. or higher. It is preferable to provide.

The method for producing a molded article of the present invention includes a housing step of containing an inorganic mixture containing silica and germanium, and having a germanium content of 10 mass ppm to 1000 mass ppm in a mold, and an inorganic mixture. It is preferable that the forming step includes the following step (a) or step (b).
(A) The process of heating to 600 degreeC or more, pressurizing an inorganic mixture with a shaping | molding die.
(B) A step of performing heat treatment at a temperature of 600 ° C. or higher after forming the inorganic mixture by pressurization.

In the molding step, the molding pressure is preferably set 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.

Method for producing a molded article of the present invention, a small particle average particle diameter D _S containing silica is less than 30nm or more 5 nm, and large particles having an average particle diameter D _L is at 40nm or more 50μm or less containing germanium and silica It is preferable to further comprise a step of mixing the above to obtain an inorganic mixture.

Method for producing a molded article of the present invention, a small particle average particle diameter D _S containing silica is less than 30nm or more 5 nm, and large particles having an average particle diameter D _L is at 40nm or more 50μm or less containing germanium and silica It is preferable to further comprise a step of mixing the metal oxide sol to obtain an inorganic mixture.

The manufacturing method of the cutting body obtained by cutting a part of the molded body of the present invention includes a molding die containing an inorganic mixture containing silica and germanium and having a germanium content of 10 mass ppm to 1000 mass ppm. A housing step, a molding step for molding the inorganic mixture, and a cutting step for cutting a part of the molded body obtained by the molding step, wherein the molding step is the following step (c) or step (d) ).
(C) heating while pressurizing the inorganic mixture by the mold as the bulk density of the molded body is less than 0.25 g / cm ³ or more 2.0 g / cm ^3.
(D) A step of applying a heat treatment at a temperature of 600 ° C. or higher after forming the inorganic mixture by pressurizing with a mold.

  According to the present invention, a molded body, an encapsulated body, a method for manufacturing a molded body, and a cutting body that can hardly be collapsed or deformed during compression, can be shaped without cutting, and have heat insulation performance. It is possible to provide a manufacturing method.

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 [1-1] Silica The molded body of the present embodiment contains silica. When the content of silica in the molded body is 50% by mass or more, heat transfer due to solid conduction is small, which is preferable for use as 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. Note that the present specification silica, other particles comprised of component represented by the composition formula SiO _2, refers to particles comprising SiO _2, a metal component or the like in addition to SiO _2, contain other inorganic compound particles These particles are sometimes referred to as silica particles. In addition to pure silicon dioxide, the silica particles may contain salts and complex oxides with Si and various other elements, or may contain hydrated oxides such as hydroxides. It may have a silanol 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. Although materials other than silica particles will be described in detail later, when the inorganic mixture contains materials other than silica particles, the content of silica particles is 50% by mass or more and 99.9% by mass based on the total mass of the molded body. % Or less is preferable. A molded product containing a silica particle content of 50 mass% or more and 97.5 mass% or less and containing inorganic fibers or 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.

[1-2] Inorganic fiber It is preferable that the molded body of this embodiment 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. For example, by applying pressure in the same direction as the heat transfer direction, the inorganic fibers oriented in the heat transfer direction can be easily oriented in a direction perpendicular to the heat transfer direction.

Examples of inorganic fibers include long glass fibers (filaments) (SiO ₂ —Al ₂ O ₃ —B ₂ O ₃ —CaO), glass fibers, glass wool (SiO ₂ —Al ₂ O ₃ —CaO—Na ₂ O). , Alkali-resistant 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 fiber (mullite fiber) (Al ₂ O ₃ —SiO ₂ ), silica fiber (SiO ₂ ), alumina fiber (Al ₂ O ₃ —SiO ₂ ), potassium titanate fiber, Alumina whisker, silicon carbide whisker, silicon nitride whisker, calcium carbonate whisker, basic magnesium sulfate whisker Car, calcium sulfate whisker (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, and blue sight.

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 due to 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 the inorganic fibers in the molded body is preferably 0.1% by mass or more based on the total mass of the molded body from the viewpoint of suppressing the detachment of the powder from the molded body. From the viewpoint of setting the specific surface area to 10 m ² / g or more and the thermal conductivity at 30 ° C. to 0.05 W / m · K or less, it is preferably 50% by mass or less.

  From the viewpoint of easy mixing with silica particles and infrared opaque particles, the content of the 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.

  The inorganic fiber may contain Ge, but in that case, after selecting the inorganic fiber having a Ge content that allows the Ge content in the molded body to be 1000 mass ppm or less, the mixing amount of the inorganic fiber is also molded. It determines so that the content rate of Ge in a body may satisfy | fill 1000 mass ppm or less. In that case, of course, the amount of Ge that the silica particles can contain decreases depending on the Ge content of the inorganic fibers. Therefore, it is preferable to previously measure the Ge content in the silica particles and the inorganic fibers. When the inorganic fiber does not contain Ge, the silica particles (or a mixture of silica particles and infrared opaque particles) should satisfy the Ge content of 10 mass ppm to 1000 mass ppm (based on the total mass of the molded product). That's fine.

[1-3] Infrared opacifying particles The molded article of the present embodiment preferably 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 infrared opaque particles are mixed in the heat insulating material, heat transfer due to radiation is suppressed, so that the heat insulating performance is particularly high in a high temperature region 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. Molded bodies containing silica, germanium, and infrared opaque particles tend to have low thermal shrinkage, for example when suddenly exposed to excessive heat, the shape changes or the molded body collapses. It has the effect of delaying.

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

  The infrared opaque particles may contain Ge. When the infrared opaque particles contain Ge, silica particles and, if contained, the infrared content is opaque by subtracting the Ge amount of inorganic fibers so that the Ge content in the entire molded product is 10 mass ppm or more and 1000 mass ppm or less. The Ge content and mixing amount of the particles are adjusted. Therefore, it is preferable to previously measure the Ge content in the silica particles and the inorganic fibers.

[1-4] Content of germanium (Ge) The molded body of the present embodiment contains Ge. The content rate of Ge is 10 mass ppm or more and 1000 mass ppm based on the total mass of the molded body. If the Ge content is less than 10 mass ppm, the compressive strength tends to be small, and if it exceeds 1000 mass ppm, the heat insulation performance tends to be low. The reason for this is not clear, but is estimated as follows. As will be described later, the production of a molded body includes a step of heat-treating the molded body. In this heat treatment step, the present inventors estimate that the inclusion of Ge in the compact lowers the melting point of silica, which is the main component of the compact, and contributes to the curing of the compact. The content of Ge is preferably 20 mass ppm or more and 900 mass ppm or less, more preferably 20 mass ppm or more and 800 mass ppm or less, based on the total mass of the molded product, from the viewpoint of sufficiently curing the molded product and increasing the compressive strength. Preferably, 20 mass ppm or more and 700 mass ppm or less are more preferable. The content of Ge in the powder can be quantified by XRF (fluorescence X-ray analysis).

If the molded body contains Ge, it is presumed that the melting point of silica, which is the main component of the molded body, is lowered when heat treatment is performed. As a result, it is considered that the silica particles are fused to each other at the particle interface to form a strong joint. In addition, Si and Ge are the same element in the periodic table, and the oxides are tetravalent, such as SiO ₂ and GeO ₂ , respectively, so that they are easily incorporated into the crystal structure and form a strong structure. it is conceivable that. It is considered that the formation of such a strong joint location or structure acts on the stabilization of the structure formed by the silica particles, so that the entire molded body is cured and the compressive strength is improved. In addition, since the germanium content is set to 1000 ppm by mass or less, it is not fused more than necessary at the interface of the silica particles, so there is no heat transfer path with large solid conduction in the molded body, and the heat of the entire molded body It is thought that the conductivity can be lowered.

  When preparing an inorganic mixture that is a raw material of a molded body by mixing a plurality of types of silica particles, for example, small particles and large particles, the content of each Ge is measured in advance, and the Ge content of the inorganic mixture after mixing is measured. It is preferable to adjust the mixing amount so that the content is 10 mass ppm or more and 1000 mass ppm or less. For example, when small particles each having a Ge content of 0 mass ppm and large particles of 1700 mass ppm are mixed, the mass of the large particles / (the mass of the small particles + the mass of the large particles) is 0.006 to 0.58. It is preferable that it is the range of these. Even when using inorganic fibers and infrared opaque particles, it is preferable to measure the Ge content in advance and determine the mixing amount. For example, when an inorganic fiber having a Ge content of 0 mass ppm is mixed with silica having a Ge content of 800 mass ppm, the mixing amount of the inorganic fibers can be arbitrarily determined. For example, when the infrared opaque particles having a Ge content of 30 mass ppm are mixed with silica having a Ge content of 800 ppm by mass, the mixing amount of the infrared opaque particles can be arbitrarily determined.

[1-5] BET specific surface area The molded body preferably has a BET specific surface area of 10 m ² / g or more and 350 m ² / g or less. A molded body having a BET specific surface area in this range tends to have a low thermal conductivity. However, the maximum load at a compression rate of 0 to 5% is not always 0.7 MPa or more. However, when the BET specific surface area is in the above range and the Ge content is 10 mass ppm or more and 1000 mass ppm or less, compressive deformation due to load tends to be small. The reason for this is not clear, but as described above, it is estimated that Ge contributes to lowering the melting point of silica, which is the main component of the molded body, and therefore, the BET specific surface area is 10 m ² / g or more and 350 m ² / g. When the Ge content is 10 mass ppm or more and 1000 mass ppm or less, the compression strength tends to increase. As a result, the compression change due to the load is small, and a molded article having excellent heat insulation performance can be obtained. Presumed. The BET specific surface area is more preferably 10 m ² / g or more and 250 m ² / g or less, and further preferably 10 m ² / g or more and 200 m ² / g or less.

When a plurality of types of silica particles, for example, small particles and large particles described later are mixed to obtain an inorganic mixture and a molded body is prepared therefrom, the BET specific surface area is measured, and the BET specific surface area is 10 m ² / g. It is preferable to adjust the mixing amount so as to be 350 m ² / g or less. For example, if the BET specific surface area of mixed small particles and 0.3 m ² / g large particles of 200 meters ² / g, respectively, of the large particle mass / (mass of small particles of mass + large particles) is from 0 to 0.88 It is preferable that it is the range of these. Also when using inorganic fibers and infrared opaque particles, it is preferable to measure the BET specific surface area in advance and determine the mixing amount. For example, when an inorganic fiber having a BET specific surface area of 0.15 m ² / g is mixed with silica having a BET specific surface area of 200 m ² / g, the mixing amount of the inorganic fibers may be 0.1% by mass to 90% by mass. preferable. For example, when the infrared opaque particles having a BET specific surface area of 2 m ² / g are mixed with silica having a BET specific surface area of 200 m ² / g, the mixing amount of the infrared opaque particles may be more than 0% by mass to 95% by mass. preferable. As will be described later, in the production of a molded body, the molded body has a step of subjecting the molded body to heat treatment. However, the molded body subjected to the heat treatment has a smaller BET specific surface area than the molded body before the heat treatment. Therefore, it is possible to measure the BET specific surface area of the molded body after the heat treatment and adjust the mixing amount of silica particles, inorganic fibers, and infrared opaque particles.

[1-6] Compressive strength The molded body of the present embodiment has a maximum load of 0.7 MPa or more in a range where the compression rate is 0 to 5%. 0.8 MPa is more preferable, and 0.9 MPa is still more preferable.

The compression rate can be calculated from the sample thickness at the time of compressive strength measurement, that is, the stroke (push-in distance) with respect to the length of the sample in the compression direction. For example, when the compression strength is measured using a sample in which the molded body has a cubic shape of 1 cm × 1 cm × 1 cm, a state where the stroke is 0.5 mm is defined as a compression rate of 5%. The compression rate is calculated by the following mathematical formula (1).
Compression rate = 100 × stroke (push-in distance) / length in sample compression direction (1)

  The pattern of the load-compression rate curve drawn at the time of compressive strength measurement is not specifically limited. That is, when the compression ratio is in the range of 0 to 5%, the molded body as the sample may collapse and show a clear breaking point, or may not collapse. When the compact that is a sample collapses and exhibits a breaking point when the compression rate is in the range of 0 to 5%, the maximum load of the compact is defined as the load at the breaking point. The load at the breaking point is preferably 0.7 MPa or more, more preferably 0.8 MPa, and even more preferably 0.9 MPa. When the sample does not collapse, evaluation is performed using the value of the maximum load indicated by the compression ratio in the range of 0 to 5%.

  The compressive strength can be measured by a method described later.

[1-7] 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 0.2 W / m · K or less, more preferably 0.19 W / m · K or less, and More preferably, it is 18 W / m · K or less. A method for measuring the thermal conductivity will be described later.

When an inorganic mixture is prepared by mixing a plurality of types of silica particles, for example, small particles and large particles, the Ge content is 10 mass ppm or more and 1000 mass ppm or less, and the BET specific surface area is 10 m ² / It is preferable to measure the thermal conductivity after setting it to g or more and 350 m ² / g or less. When the thermal conductivity is more than 0.05 W / m · K, the mixing amount is within the range of maintaining the Ge content of 10 mass ppm to 1000 mass ppm and the BET specific surface area of 10 m ² / g to 350 m ² / g. Is preferably changed. In the case of using inorganic fibers and infrared opaque particles, the mixing amount can be similarly determined. When an inorganic mixture that is a raw material of a molded body is prepared by mixing small particles and large particles, a tendency is seen that the thermal conductivity is smaller than when the inorganic mixture is composed of only large particles. For example, when mixing small particles of about 10 nm and large particles of about 5 μm, the mass of large particles / (the mass of small particles + the mass of large particles) is preferably 0.02 to 0.95. If the mixing amount of the inorganic fibers and the infrared opaque particles 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.

[1-8] Content of Fe and Other Elements The powder of the present embodiment has excellent moldability and has a Fe content of 0 based on the total mass of the powder from the viewpoint of reducing powder scattering. 0.005% by mass to 6% by mass is preferable, 0.005% by mass to 3% by mass is more preferable, 0.005% by mass to 2% by mass is further preferable, and 0% by mass. It is particularly preferable that the content is 0.005% by mass or more and 1% by mass or less. The powder may contain potassium (K), magnesium (Mg), calcium (Ca), phosphorus (P), and sulfur (S) in addition to Ge and Fe. As for the content of each element, the K content is 0.003 to 2% by mass, the Mg content is 0.002 to 2% by mass, and the Ca content is 0.002% by mass or more. 0.5 mass% or less, P content is preferably 0.003 mass% or more and 0.3 mass% or less, and S content is preferably 0.003 mass% or more and 0.3 mass% or less. The content is 0.003% by mass to 1.5% by mass, the Mg content is 0.002% by mass to 1.8% by mass, and the Ca content is 0.002% by mass to 0.4% by mass. Hereinafter, it is more preferable that the P content is 0.003% by mass or more and 0.25% by mass or less, the S content is 0.003% by mass or more and 0.02% by mass or less, and the K content is 0.003% by mass or more and 1.0% by mass or less, and the Mg content is 0.002% by mass or more and 1.6% by mass or less. The Ca content is 0.002 mass% to 0.2 mass%, the P content is 0.003 mass% to 0.2 mass%, and the S content is 0.003 mass% to 0.003 mass%. More preferably, it is 1 mass% or less.

[2] Manufacturing method of molded body The manufacturing method of the molded body of the present embodiment includes a step of heat-treating an inorganic mixture containing silica and germanium and having a germanium content of 10 mass ppm to 1000 mass ppm. . The manufacturing method includes a housing step of housing the inorganic mixture in a mold and a molding step of molding the inorganic mixture, and the molding step (a) heats the inorganic mixture to 600 ° C. or higher while pressurizing the inorganic mixture with the mold. It is preferable to have the process or (b) the process of heat-processing at the temperature of 600 degreeC or more, after shape | molding an inorganic mixture by pressurization. Hereinafter, the raw material used for manufacture of a molded object and each process are demonstrated.

[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. Silica particles preferably have water resistance from the viewpoint of maintaining heat insulating performance when used as a heat insulating material and from the viewpoint of maintaining the shape of the molded body. 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 of this embodiment may contain only one kind of silica particles, or may contain two or more kinds. In particular, when containing two types of particles with different particle sizes, ie, small particles and large particles made of silica, the BET specific area and thermal conductivity are different from those when only small particles or large particles are present. By mixing two kinds of particles, the BET specific area and / or the thermal conductivity can be adjusted. For example, a large particle having an average particle diameter _DL of 30 nm or more and 50 μm or less may have a BET specific surface area of less than 10 m ² / g, but when a small particle of 5 nm or more and less than 30 nm is mixed with this, the BET specific surface area is reduced. It is easy to make it 10 m ² / g or more. Moreover, since the large particles have large solid heat conduction, the heat conductivity may be more than 0.05 W / m · K. By mixing small particles with this, the solid heat conduction is suppressed, and 0.05 W / M · K or less. As for the compressive strength, those consisting only of small particles may be too small, but it is easy to adjust the maximum load at a compression rate of 0 to 5% to 0.7 MPa or more by adding large particles to small particles. Tend to be.

When the molded body of the present embodiment contains two or more types of silica particles, the molded body has a BET specific surface area of 10 m ² / g to 350 m ² / g and a thermal conductivity of 0.05 W / m · The content ratio of large particles and small particles may be adjusted so as to be not more than K. For example, when mixing small particles of about 10 nm and large particles of about 5 μm, preferably the mass of large particles / (the mass of small particles + When the mass of the large particles is 0.02 to 0.95, more preferably 0.10 to 0.90, and particularly preferably 0.15 to 0.85, the BET specific surface area is about 250 m ² / g to 40 m ^2. / B, and the BET specific surface area can be adjusted. The void formed by these particles becomes a bottleneck for heat conduction in the space, and heat conduction in the space is easily suppressed. 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 such a powder is desired, 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 considered not suitable as a heat-insulating material, for example, even if particles with a particle size not so small on the order of micrometers are used as raw materials, they are mixed with ultrafine particles (small particles) in an appropriate amount. It has been discovered that it is possible to develop excellent heat insulation performance. Utilizing this discovery is one of the preferred embodiments of the present invention. The heat treatment tends to increase the compressive strength and thermal conductivity of the molded product, and the BET surface area tends to decrease. Therefore, when heat-treating the molded product, the compressive strength and thermal conductivity after the heat treatment are performed. The rate and BET specific surface area are measured.

The particle diameter of the silica particles affects the BET specific surface area of the molded body, and when the molded body is composed only of silica, the BET specific surface area of the silica particles is preferably 10 m ² / g or more and 350 m ² / g or less, When the inorganic mixture contains a component other than silica particles, it is preferable to set the particle size of silica in view of the BET specific surface area of the component. Specifically, when the inorganic mixture contains inorganic fibers, the BET specific surface area of general inorganic fibers is smaller than the BET specific surface area of silica, so the BET specific surface area of silica is about 50 m ² / g to 400 m ² / It is preferable to be about g, and the particle diameter of the silica particles is preferably about 7 nm to about 50 nm. When the inorganic mixture contains infrared opaque particles, the BET specific surface area of general infrared opaque particles is smaller than the BET specific surface area of silica, so the BET specific surface area of silica is about 70 m ² / g to 450 m ² / g. The particle diameter of the silica particles is preferably about 5 nm to 40 nm. The particle diameter of the silica particles can be measured by observing with a field emission scanning electron microscope (FE-SEM). The average particle diameter D _S of the small particles and the average particle diameter D _L of the large particles are obtained by observing 1000 small particles and 1000 large particles, respectively, with an FE-SEM, calculating the equivalent area circle equivalent diameter, and calculating the number average. Can be confirmed. From the viewpoint of solid conduction of the silica particles, the average particle size of the silica particles is preferably 10 nm or more and less than 80 μm, more preferably 10 nm or more and less than 50 μm, and even more preferably 10 nm or more and less than 30 μm.

In the molded body containing the large particles and small particles in the raw material, the average particle diameter D _S of the small particles is preferably less than or more 5 nm 30 nm. 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 less than 30 nm, 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, more preferably from the viewpoint of reducing the thermal conductivity and further preferably 5nm or 15nm or less.

The average particle size D _L of the large particles preferably satisfies D _S <D _L and is 40 nm or more and 50 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. Here, the term “springback” refers to a phenomenon in which the molded body expands greatly when the pressure is released after pressure-molding a heat insulating material precursor containing ultrafine particles as a main component. When _DL is 50 μm or less, the thermal conductivity tends to be small.

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 more 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, further 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.

  It is preferable that the molded body 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 silicone 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. Moreover, it is also possible to apply the water repellent as it is or in the form of a solution or an emulsion to a molded body obtained by pressure molding an inorganic mixture. Although the method of apply | coating is not specifically limited, For example, brush coating, roller coating, spraying, spraying, airless spray, roll coater, immersion, etc. 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. In the present embodiment, a wax-based water repellent and a silicon-based water repellent are preferably used. The content ratio of the water repellent in the inorganic mixture is preferably 100/30 to 100 / 0.1 in terms of the mass ratio of the entire inorganic mixture / the mass of the water repellent 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 are used as raw materials, and the germanium 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.

  As silica particles, it is possible to use natural silicate minerals. Examples of natural minerals include olivine, chlorite, quartz, feldspar, zeolite and the like. By subjecting natural silicate minerals to treatment such as grinding, the BET specific surface area can be adjusted and used as silica particles. When the Ge content is insufficient or excessive, the addition or removal treatment of Ge is performed by the method described later to adjust the Ge content to an arbitrary value, and it can be used as silica particles constituting the inorganic mixture. Is possible.

[2-2] Ge
When the silica particles include small particles and large particles, at least one of the small particles and the large particles may include Ge. Further, a compound containing Ge may be added to small particles, large particles, or small particles and large particles that do not contain Ge. Moreover, it is preferable that a small particle or a large particle contains Ge so that the content rate of Ge in powder may be 10 mass ppm or more and 1000 mass ppm or less. Depending on the origin, there may be silica containing 10 to 1000 ppm by mass of Ge. However, since the Ge concentration of silica is generally less than 10 ppm by mass, the Ge concentration should be adjusted within this range. preferable. In a silica production process or a powder production process, a Ge-containing silica particle can be obtained by adding a Ge-containing compound to 10 to 1000 ppm by mass. As the compound containing Ge, but are not limited to, for example, oxides of Ge, composite oxide, nitride, inorganic germanium compounds such as carbide, germanium tetraethoxide as germanium alkoxide _{[Ge (C 2 H 5 O} ) 4 ], Germanium tetra-n-butoxide [Ge (C ₄ H ₉ O) ₄ ], germanium tetraisopropoxide [Ge (C ₃ H ₇ O) ₄ ], and carboxyethyl germanium sesquioxide [(GeCH ₂ CH ₂ Organic germanium such as COOH) ₂ O ₃ ], tetraethyl germanium [Ge (C ₂ H ₅ ) ₄ ], tetrabutyl germanium [Ge (C ₄ H ₉ ) ₄ ], tributyl germanium [Ge (C ₄ H ₉ ) ₃ ] Compounds. These may be added alone or a mixture thereof may be added. If the concentration is 10 to 1000 ppm by mass, it is possible to use inorganic compound particles containing silica containing Ge as an impurity as a raw material for powder after adjusting the thermal conductivity, etc., in terms of productivity, cost, workability From the viewpoint of, this is a preferred embodiment.

  The method for adding the compound containing Ge 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 Ge may be water-soluble or insoluble in water. It may be added as an aqueous solution and / or slurry of a compound containing Ge, and may be dried as necessary, or the compound containing Ge may be added in a solid or liquid state. The compound containing Ge may be previously pulverized to a predetermined particle diameter, or may be coarsely pulverized in advance.

  In the case where the silica particles contain an excessive amount of Ge, it is preferable to adjust the Ge content to 10 to 1000 mass ppm by applying some treatment to the silica particles. The method for adjusting the excess amount of Ge to 10 to 1000 ppm by mass is not particularly limited. For example, a method of substitution, extraction, removal, etc. with an acidic substance or an alkaline substance, or other elements is mentioned. After treating inorganic compound particles containing silica with aqua regia or sodium peroxide aqueous solution, etc., they are dried, It can be used as a raw material. The excessive amount of Ge may be reduced after the inorganic compound particles containing silica are pulverized to a desired particle size in advance, or the silica particles may be pulverized after adjusting Ge to a predetermined range.

[2-3] Fe and other elements Fe, K, Mg, Ca, P, and S are compounds containing Fe, K, Mg, Ca, P, and S during the silica manufacturing process and the powder manufacturing process. However, silica particles containing a sufficient amount of Fe, K, Mg, Ca, P, or S in advance may be used. Although it does not specifically limit as a compound containing Fe, K, Mg, Ca, P, S, For example, the oxide of Fe, K, Mg, Ca, P, S, complex oxide, hydroxide, nitride, carbide , Carbonates, acetates, nitrates, sparingly soluble salts, and alkoxides. These may be added alone or a mixture thereof may be added. The use of inorganic compound particles containing silica containing Fe, K, Mg, Ca, P, and S as impurities is a preferred 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 of adding a compound containing each of Fe, K, Mg, Ca, P, and S to the silica particles is not particularly limited. For example, you may add to the silica particle which does not contain these metals, and may add these metals in the manufacturing process of a silica. The compound containing each of Fe, K, Mg, Ca, P, and S may be water-soluble or insoluble in water. It may be added as an aqueous solution of a compound containing Fe, K, Mg, Ca, P, or S, and may be dried as necessary, or a compound containing Fe, K, Mg, Ca, P, or S may be solid. Alternatively, it may be added in a liquid state. The compound containing Fe, K, Mg, Ca, P, and S may be previously pulverized to a predetermined particle diameter, or may be preliminarily coarsely pulverized.

  If the silica particles contain an excessive amount of Fe, K, Mg, Ca, P, or S, some processing is performed during the silica manufacturing process or the powder manufacturing process to determine the content of the element. You may adjust to the range. A method for adjusting an excessive amount of Fe, K, Mg, Ca, P, and S to a predetermined range is not particularly limited. For example, the method for adjusting the Fe content includes substitution, extraction, removal, etc. with an acidic substance or other elements. After treating inorganic compound particles containing silica with aqua regia etc., they are dried and powdered. It can be used as a raw material for the body. Adjustment of an excessive amount of Fe, K, Mg, Ca, P, and S may be performed after previously pulverizing inorganic compound particles containing silica to a preferable particle diameter, or Fe, K, Mg, Ca, P, Silica particles may be pulverized after adjusting S to a preferred range.

[2-4] Mixing method Silica particles, infrared opacifying particles and inorganic fibers can be mixed using a known powder mixer, for example, those described in the revised sixth edition Chemical Engineering Handbook (Maruzen). At this time, it is also possible to mix two or more types of silica particles, 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.

  A metal oxide sol may be added to the silica particles in addition to or instead of the inorganic fibers and the infrared opaque particles. The metal oxide sol becomes an inorganic binder, and a molded article having high compressive strength can be easily obtained. When mixing a plurality of types of silica particles, from the viewpoint of highly dispersing the metal oxide sol throughout the molded body, for example, after mixing small particles and large particles in advance by the above-described method, the metal oxide sol is added. It is preferable to mix. When mixing the metal oxide sol, as in the case of mixing small particles and large particles, using a pulverizer equipped with a known stirring blade, pulverize the particles, cut the inorganic fiber, While improving the dispersibility of the particles and inorganic fibers, it is preferable to mix with the peripheral speed at the tip of the stirring blade being 100 km / h. In order to improve the dispersibility of the metal oxide sol, it is preferable to use a powder mixer having a stirring blade, and the peripheral speed at the tip of the stirring blade is preferably 100 km / h or more, and there is less contact between large particles. In view of the above, 200 km / h or more is more preferable, and 300 km / h or more is more preferable.

  Examples of the metal oxide sol include silica sol, alumina sol, zirconia sol, ceria sol, and titania sol. Silica sol and alumina sol are preferable from the viewpoint of reducing thermal conductivity and heat resistance. The particle diameter of the metal oxide sol is preferably 2 nm to 450 nm, more preferably 4 nm to 300 nm, and even more preferably 4 nm to 200 nm from the viewpoint of reducing the thermal conductivity.

  From the viewpoint of preventing the mixture from adhering to the inner wall of the stirring tank and mixing from becoming uneven when mixing with silica, inorganic fibers, and infrared opaque particles, the amount of metal oxide sol added is the mass of the molded body. The solid content of the metal oxide sol is preferably 0.5% by mass to 30% by mass, more preferably 1% by mass to 25% by mass, and even more preferably 2% by mass to 25% by mass.

[2-5] Molding Method The molded body of the present embodiment can be obtained by pressure-molding an inorganic mixture as a raw material, and the molding step and the heating step described later may be performed simultaneously with (a). (B) You may perform a heating process after a formation process. That is, (a) a method in which a mold (molding die) filled (accommodated) with an inorganic compound is pressurized while being heated, or (b) an inorganic compound is formed by pressurizing the mold in a state filled with the inorganic compound. After molding, a method may be used in which the obtained molded body is taken out of the mold or heated in a state of being put in the mold. In both embodiments, the preferred pressure and heating temperature are approximately the same.

  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 the conditions of pressure molding are set from the viewpoint of making the maximum load and / or the thermal conductivity at a compression rate of 0 to 5% as desired, the bulk density of the resulting molded body is 0.25 g / cm ³ or more 2 It is preferable to set it to 0.0 g / cm ³ or less. 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 obtained molded body can be easily set to the target value without requiring time control. The bulk density of the molded body from the viewpoint of reducing the burden during transportation, 0.25 g / cm ³ or more 1.7 g / cm ³ or less, more preferably, 0.25 g / cm ³ or more 1.5 g / cm ³ or less is more preferable. The molding pressure at which the bulk density of the molded body is 0.25 g / cm ³ or more and 2.0 g / cm ³ or less is, for example, 0.01 MPa or more and 50 MPa or less, and 0.25 g / cm ³ or more and 1.7 g. / cm ³ the molding pressure equal to or less than a pressure of less than 40MPa example 0.01MPa or more, 0.25 g / cm ³ or more 1.5 g / cm ³ pressure 30MPa, for example 0.01MPa or more as the molding pressure equal to or less than It is.

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. It is preferably formed by compressing the body.

[2-6] Heat treatment method The molded body during or after pressure molding is heat-dried within the range of temperature and time sufficient for the heat resistance of the molded body to adsorb water on the molded body. It is preferable to put it to practical use after removing the heat resistance because the thermal conductivity is lowered. Furthermore, you may heat-process.

  It is preferable that the manufacturing method of the molded object of this embodiment has the process of heat-processing the molded object formed by adding an infrared opaque particle and inorganic fiber according to a use condition including a silica and germanium. 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 use of a molded object, specifically 600-1200 degreeC is preferable, More preferably, it is 700-1200 degreeC, More preferably, it is 800-1200 degreeC.

  In order to set the maximum load at a compression rate of 0 to 5% to 0.7 MPa or more, the molded body can contain the metal oxide sol as described above. When the molded body contains a metal oxide sol, the molded body tends to be hardened at a lower heat treatment temperature, and thus, specifically, 200 to 1200 ° C is preferable, more preferably 300 to 1200 ° C, and further Preferably it is 400-1200 degreeC.

  Heat treatment can be performed in air (or in the air), in oxidizing atmospheres (oxygen, ozone, nitrogen oxides, carbon dioxide, hydrogen peroxide, hypochlorous acid, inorganic / organic peroxides, etc.) Examples include an active gas atmosphere (helium, argon, nitrogen, etc.). What is necessary is just to select heat processing time suitably according to heat processing temperature and the quantity of a molded object.

  The heat treatment may be performed after filling the portion where the inorganic mixture, which is the raw material of the molded body, is used, or may be applied to a pressure-molded inorganic mixture.

[2-7] Manufacturing method of cutting body The cutting body of this embodiment can obtain a cutting body by cutting a part. As a manufacturing method of a cutting body, for example, an accommodation step of containing an inorganic mixture containing silica and germanium and having a germanium content of 10 mass ppm or more and 1000 mass ppm or less in a mold, and molding the inorganic mixture are performed. A molding step and a cutting step of cutting a part of the molded body obtained by the molding step. The cutting means of the molded body is not particularly limited, but cutters, circular saws, jigsaws, yarn saws, drills, grinders, band saws, side cutters, general-purpose lathes, lathes such as table lathes and NC lathes, general-purpose milling machines, A vertical machining center, a horizontal machining center, a milling machine such as a 5-axis processing machine can be used, and a hand saw, a lathe, and a milling machine are particularly preferably used.

Here, in the forming step in the method for manufacturing a cut body, from the viewpoint of making it difficult to collapse during cutting and processing, (c) the bulk density of the formed body is set to 0.25 g / cm ³ or more and 2.0 g / cm ³ or less. It is preferable to include a step of heating while pressing the mold so that (d) a step of performing heat treatment at a temperature of 600 ° C. or higher after forming the inorganic mixture by pressurizing the mold. preferable.

[3] Encapsulant The encapsulant includes a molded body and a jacket material that accommodates the molded body. The encapsulated body has the advantage that it is easier to handle and easier to construct than the molded body. FIG. 1 is an example of a schematic cross-sectional view of an enveloping body according to the present embodiment. FIG. 2 is an example of a schematic cross-sectional view of small particles and large particles according to the present 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. In addition, a molded object may be called 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 of the present embodiment contains silica particles, and an inorganic mixture formed by adding large particles, infrared opaque particles and inorganic fibers according to the usage conditions is used as a raw material. The inorganic mixture may be pressure-molded to form a core material, which may be covered 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 encapsulant containing silica particles and Ge according to 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, and an adsorption It can also be suitably used for carriers that adsorb chemicals such as fragrances, fragrances and bactericides, deodorants, deodorants, humidity control materials, fillers, pigments and the like.

[5] Measurement of parameters Measurement of the Ge content of the inorganic mixture, measurement of the BET specific surface area, measurement of compressive strength, and measurement of thermal conductivity are carried out by the following methods.

[Measurement of Ge Content]
The molded body is pulverized with a menor mortar, filled into a 30 mmφ polyvinyl chloride ring, and pressure-molded with an XRF tablet molding machine to prepare a tablet, which is used as a measurement sample. This is measured with a fluorescent X-ray analyzer RIX-3000 manufactured by Rigaku Corporation.

[Compressive strength]
The molded body is processed to a length of 2 cm, a width of 2 cm, and a thickness of 2 cm, and the compressive strength is measured at an indentation speed of 0.5 mm / min using a precision universal testing machine Autograph AG-100KN manufactured by Shimadzu Corporation.

[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.

  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 addition, the measurement of the content rate of Ge of the inorganic mixture in an Example and a comparative example, the measurement of thermal conductivity, and the measurement of compressive strength were as above-mentioned respectively.

[Example 1]
Silica powder having a Ge content of 0 mass ppm was added to an ethanol solution of germanium (IV) isopropoxide and stirred until it was completely dried. The obtained powder was heat-treated at 100 ° C. for 24 hours, and further heated at 700 ° C. for 24 hours. In order to obtain a molded body having a length of 30 cm, a width of 30 cm, a thickness of 20 mm, and a bulk density of 0.25 g / cm ^3, a mold having an inner dimension of 30 cm in length and 30 cm in width is filled with 450 g of silica powder and subjected to pressure molding. As a result, a molded body having a bulk density of 0.25 g / cm ³ was obtained. This molded body was subjected to a heat treatment at 1000 ° C. for 24 hours to obtain a molded body of Example 1. The Ge content of the molded body of Example 1 was 21 ppm by mass, and the thermal conductivity at 30 ° C. was 0.0201 W / m · K. The molded body was cut in the vertical direction to produce 25 cutting bodies having a length of 6 cm, a width of 6 cm, and a thickness of 20 mm. None of these cutting bodies were chipped or damaged. Further, the cutting body having a length of 6 cm, a width of 6 cm, and a thickness of 20 mm was cut and processed into a length of 2 cm, a width of 2 cm, and a thickness of 2 cm, and the compressive strength was measured. As a result, the sample collapsed at a compression rate of 3.9%. The fracture point was indicated, and the load at this time was 0.7 MPa.

[Example 2]
A silica powder obtained by uniformly mixing 50% by mass of silica powder (small particles) with a Ge content of 0 mass ppm and 50% by mass of silica powder (large particles) with a Ge content of 571 mass ppm by a hammer mill. Obtained. Using 594 g of this silica powder, pressure molding was performed in the same manner as in Example 1 to obtain a molded body having a length of 30 cm, a width of 30 cm, a thickness of 20 mm, and a bulk density of 0.33 g / cm ³ , and then at 1000 ° C. The molded body of Example 2 was obtained by performing a heat treatment for 5 hours. The Ge content of the molded body of Example 2 was 286 ppm by mass, and the thermal conductivity at 30 ° C. was 0.0198 W / m · K. The molded body of Example 2 was cut in the same manner as in Example 1 to prepare 25 cutting bodies. None of these cutting bodies were chipped or damaged. Furthermore, as a result of measuring the compressive strength in the same manner as in Example 1, the maximum load at a compression rate of 5.0% was 0.8 MPa.

Further, using the above silica powder, pressurization and heating were performed at 1000 ° C. for 5 hours using a hot press machine so that the length was 30 cm, the width was 30 cm, and the thickness was 20 mm. The obtained molded body had a thermal conductivity of 0.0199 W / m · K at 30 ° C. Although 25 cut bodies were prepared by cutting in the same manner as in Example 1, none of these cut bodies were chipped or damaged. Furthermore, as a result of measuring the compressive strength in the same manner as in Example 1, the maximum load at a compression rate of 5.0% was 0.9 MPa. The average particle diameter _{D S} of the small particles was 7.5 nm, the average particle diameter _{D L} of the large particles was 80 nm.

[Example 3]
A silica powder obtained by uniformly mixing 25% by mass of silica powder (small particles) having a Ge content of 0 mass ppm and 75% by mass of silica powder (large particles) having a Ge content of 0 mass ppm by a hammer mill. Obtained. This silica powder was added to an ethanol solution of germanium (IV) isopropoxide and stirred until it was completely dried. The obtained powder was heat-treated at 100 ° C. for 24 hours, and further heated at 700 ° C. for 24 hours. Using 1260 g of this powder, pressure molding was carried out in the same manner as in Example 1 to obtain a molded body having a length of 30 cm, a width of 30 cm, a thickness of 20 mm, and a bulk density of 0.70 g / cm ³ , and 5 ° C. at 1000 ° C. The heat treatment was performed for a time, and the molded body of Example 3 was obtained. The Ge content of the molded body of Example 3 was 897 mass ppm, and the thermal conductivity at 30 ° C. was 0.0314 W / m · K. The molded body of Example 3 was cut in the same manner as in Example 1 to produce 25 cutting bodies. None of these cutting bodies were chipped or damaged. Furthermore, as a result of measuring the compressive strength in the same manner as in Example 1, the sample collapsed to show a breaking point at a compression rate of 2.8%, and the load at this time was 1.6 MPa. The average particle diameter _{D S} of the small particles is 14 nm, the average particle diameter _{D L} of the large particles was 10 [mu] m.

[Example 4]
22.5% by mass of silica powder (small particles) having a Ge content of 0 mass ppm and 67.5% by mass of silica powder (large particles) having a Ge content of 571 mass ppm were uniformly mixed with a hammer mill. Thereafter, 10% by mass of glass fiber having an average fiber diameter of 11 μm, an average fiber length of 6.4 mm, and a heat resistant temperature of 1050 ° C. was added and mixed with a high-speed shear mixer to obtain a silica powder. Using 864 g of this powder, pressure molding was carried out in the same manner as in Example 1 to obtain a molded body having a length of 30 cm, a width of 30 cm, a thickness of 20 mm, and a bulk density of 0.48 g / cm ³ , and then 24 ° C. at 24 ° C. The heat treatment was performed for a time, and the molded body of Example 4 was obtained. The Ge content of the molded body of Example 4 was 385 mass ppm, and the thermal conductivity at 30 ° C. was 0.0263 W / m · K. The molded body of Example 4 was cut in the same manner as in Example 1 to prepare 25 cutting bodies. None of these cutting bodies were chipped or damaged. Furthermore, as a result of measuring the compressive strength in the same manner as in Example 1, the sample collapsed to show a breaking point at a compression rate of 3.0%, and the load at this time was 1.7 MPa. The average particle diameter _{D S} of the small particles was 7.5 nm, the average particle diameter _{D L} of the large particles was 80 nm.

[Example 5]
After uniformly mixing 19% by mass of silica powder (small particles) having a Ge content of 0 mass ppm and 57% by mass of silica powder (large particles) having a Ge content of 571 mass ppm with a hammer mill, average particles High-speed shear mixer with the addition of 14% by mass of zirconium silicate which is an infrared opaque particle having a diameter of 1 μm, an average fiber diameter of 11 μm, an average fiber length of 6.4 mm and a heat-resistant temperature of 1050 ° C. To obtain a silica powder. Using 972 g of this powder, pressure molding was carried out in the same manner as in Example 1 to obtain a molded body having a length of 30 cm, a width of 30 cm, a thickness of 20 mm, and a bulk density of 0.54 g / cm ^3. The heat processing for time was performed and the molded object of Example 5 was obtained. The Ge content of the molded body of Example 5 was 325 ppm by mass, and the thermal conductivity at 30 ° C. was 0.0273 W / m · K. The molded body of Example 5 was cut in the same manner as in Example 1 to produce 25 cutting bodies. None of these cutting bodies were chipped or damaged. Furthermore, as a result of measuring the compressive strength in the same manner as in Example 1, the sample collapsed to show a breaking point when the compression rate was 3.4%, and the load at this time was 1.9 MPa. The average particle diameter _{D S} of the small particles was 7.5 nm, the average particle diameter _{D L} of the large particles was 80 nm.

[Example 6]
Using 1170 g of silica powder having a Ge content of 571 ppm by mass and an average particle size of 80 nm, pressure molding was performed in the same manner as in Example 1, and the length was 30 cm, the width was 30 cm, the thickness was 20 mm, and the bulk density was 0.65 g / After obtaining a molded product of cm ³ , heat treatment was performed at 1000 ° C. for 5 hours to obtain a molded product of Example 6. The Ge content of the molded body of Example 5 was 571 ppm by mass, and the thermal conductivity at 30 ° C. was 0.0387 W / m · K. The molded body of Example 5 was cut in the same manner as in Example 1 to produce 25 cutting bodies. None of these cutting bodies were chipped or damaged. Furthermore, as a result of measuring the compressive strength in the same manner as in Example 1, the sample collapsed to show a breaking point at a compression rate of 2.8%, and the load at this time was 1.3 MPa.

[Example 7]
A 0.5% carboxyethyl germanium sesquioxide aqueous solution, a silica sol solution having a colloidal particle diameter of 10 to 20 nm kept at 15 ° C. (manufactured by Nissan Chemical Co., Ltd., trade name “Snowtex 40”, SiO ₂ content: 40 (Mass%) was gradually added dropwise to obtain a mixed slurry of silica sol and carboxyethyl germanium sesquioxide. Thereafter, the mixed slurry was spray-dried with a spray dryer apparatus whose outlet temperature was set to 130 ° C. to obtain a solid. Next, the obtained solid was heated in an electric furnace from room temperature to 300 ° C. over 2 hours and then held at 300 ° C. for 3 hours. Further, the temperature was raised to 550 ° C. in 2 hours, held at 550 ° C. for 3 hours, calcined, and then gradually cooled to obtain the silica powder of Example 7. Using 990 g of this powder, pressure molding was carried out in the same manner as in Example 1 to obtain a molded body having a length of 30 cm, a width of 30 cm, a thickness of 20 mm, and a bulk density of 0.55 g / cm ³ , and then 24 ° C. at 1000 ° C. The heat processing for time was performed and the molded object of Example 7 was obtained. The Ge content of the molded body of Example 7 was 53 ppm by mass, and the thermal conductivity at 30 ° C. was 0.0341 W / m · K. The molded body of Example 7 was cut in the same manner as in Example 1 to produce 25 cutting bodies. None of these cutting bodies were chipped or damaged. Furthermore, as a result of measuring the compressive strength in the same manner as in Example 1, the sample collapsed to show a breaking point at a compression rate of 2.6%, and the load at this time was 0.8 MPa.

[Example 8]
Silicon tetrachloride and germanium tetrachloride were supplied into a flame formed by supplying oxygen gas and hydrogen gas to the burner, and porous glass particles were deposited on the target rod. The glass fine particles were collected to obtain a silica powder having a Ge content of 357 ppm by mass and a BET specific surface area of 117 m ² / g. Using 450 g of this powder, pressure molding was carried out in the same manner as in Example 1 to obtain a molded body having a length of 30 cm, a width of 30 cm, a thickness of 20 mm, and a bulk density of 0.25 g / cm ³ , and then 5 ° C. at 1000 ° C. The heat processing for time was performed and the molded object of Example 8 was obtained. The Ge content of the molded body of Example 8 was 473 mass ppm, and the thermal conductivity at 30 ° C. was 0.0215 W / m · K. The molded body of Example 8 was cut in the same manner as in Example 1 to produce 25 cutting bodies. None of these cutting bodies were chipped or damaged. Furthermore, as a result of measuring the compressive strength in the same manner as in Example 1, the sample collapsed to show a breaking point when the compression rate was 3.1%, and the load at this time was 1.0 MPa.

[Example 9]
After uniformly mixing 21% by mass of silica powder (small particles) with a Ge content of 0% by mass and 64% by mass of silica powder (large particles) with a Ge content of 571 ppm by mass using a hammer mill, average particles The silica powder of Example 9 was obtained by adding 15% by mass of zirconium silicate, which is an infrared opaque particle having a diameter of 1 μm, and then mixing uniformly. Using 918 g of this powder, pressure molding was performed in the same manner as in Example 1 to obtain a molded body having a length of 30 cm, a width of 30 cm, a thickness of 20 mm, and a bulk density of 0.51 g / cm ³ , and then 5 ° C. at 1000 ° C. The heat processing for time was performed and the molded object of Example 9 was obtained. The Ge content of the molded body of Example 9 was 365 ppm by mass, and the thermal conductivity at 30 ° C. was 0.0273 W / m · K. Further, each of the 721 g of the 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. Using these two molded bodies, the thermal conductivity at 800 ° C. was measured to be 0.0633 W / m · K. The molded body of Example 9 was cut in the same manner as in Example 1 to prepare 25 cutting bodies. None of these cutting bodies were chipped or damaged. Furthermore, as a result of measuring the compressive strength in the same manner as in Example 1, the sample collapsed to show a breaking point at a compression rate of 4.4%, and the load at this time was 0.8 MPa. The average particle diameter _{D S} of the small particles is 14 nm, the average particle diameter _{D L} of the large particles was 80 nm.

[Example 10]
After uniformly mixing 21% by mass of silica powder (small particles) having a Ge content of 0 mass ppm and 63% by mass of silica powder (large particles) having a Ge content of 571 mass ppm with a hammer mill, average particles High-speed shear mixer with the addition of 15% by mass of zirconium silicate which is an infrared opaque particle having a diameter of 1 μm, an average fiber diameter of 11 μm, an average fiber length of 6.4 mm and a heat-resistant temperature of 1050 ° C. To obtain a silica powder. Using 864 g of this powder, pressure molding was carried out in the same manner as in Example 1 to obtain a molded body having a length of 30 cm, a width of 30 cm, a thickness of 20 mm, and a bulk density of 0.48 g / cm ³ , and 5 ° C. at 1000 ° C. The heat processing for time was performed and the molded object of Example 10 was obtained. The Ge content of the molded body of Example 10 was 357 ppm by mass, and the thermal conductivity at 30 ° C. was 0.0246 W / m · K. The molded body of Example 10 was cut in the same manner as in Example 1 to prepare 25 cutting bodies. None of these cutting bodies were chipped or damaged. Furthermore, as a result of measuring the compressive strength in the same manner as in Example 1, the maximum load at a compression rate of 5.0% was 0.9 MPa. The average particle diameter _{D S} of the small particles is 14 nm, the average particle diameter _{D L} of the large particles was 80 nm.

[Comparative Example 1]
A molded article of Comparative Example 1 was obtained in the same manner as Example 1 except that Ge was not added. An attempt was made to cut the molded body of Comparative Example 1 in the same manner as in Example 1 to create 25 cutting bodies, but chipping and breakage were severe, and a cutting body having a length of 6 cm, a width of 6 cm, and a thickness of 20 mm could not be obtained. It was. Furthermore, as a result of measuring the compressive strength in the same manner as in Example 1, in the range of compression rate = 0 to 5%, the sample was deformed with compression and showed no clear breaking point, and the load at the compression rate = 5% was It was 0.1 MPa.

[Comparative Example 2]
A molded body of Comparative Example 2 was obtained in the same manner as in Example 6 except that the heat treatment was not performed. The molded body of Comparative Example 2 was cut in the same manner as in Example 1 to create 25 cutting bodies. However, chipping and breakage were severe, and a cutting body having a length of 6 cm, a width of 6 cm, and a thickness of 20 mm could not be obtained. It was. Furthermore, as a result of measuring the compressive strength in the same manner as in Example 1, in the range of compression rate = 0 to 5%, the sample was deformed with compression and showed no clear breaking point, and the load at the compression rate = 5% was It was 0.3 MPa.

[Comparative Example 3]
Silica powder having a Ge content of 571 mass ppm was added to an ethanol solution of germanium (IV) isopropoxide and stirred until it was completely dried. The obtained powder was heat-treated at 100 ° C. for 24 hours, and further heated at 700 ° C. for 24 hours. Using 1170 g of this powder, pressure molding was carried out in the same manner as in Example 1 to obtain a molded body having a length of 30 cm, a width of 30 cm, a thickness of 20 mm, and a bulk density of 0.65 g / cm ³ , and 5 ° C. at 1000 ° C. When the heat treatment was performed for a time, cracks occurred in the molded body, and the thermal conductivity could not be measured. In addition, the content rate of Ge of the compact | molding | casting of the comparative example 3 is 1107 mass ppm, As a result of measuring compressive strength like Example 1, a sample collapse | disintegrates and a fracture point is obtained in compression rate = 1.9%. As shown, the load at this time was 2.1 MPa.

  DESCRIPTION OF SYMBOLS 1 ... Enveloping body (heat insulating material), 2 ... Core material (molded body), 3 ... Outer covering material, S ... Small particle, L ... Large particle.

Claims (15)

Containing silica and germanium,
The germanium content is 10 mass ppm or more and 1000 mass ppm or less, the maximum load at a compression rate of 0 to 5% is 0.7 MPa or more, and the thermal conductivity at 30 ° C. is 0.05 W / m · K or less. There is a molded body. The molded article according to claim 1, further comprising infrared opaque particles and having a thermal conductivity at 800 ° C of 0.2 W / m · K or less.   The average particle diameter of the infrared opaque particles is 0.5 μm or more and 30 μm or less, and the content of the infrared opaque particles is 0.1 mass% or more and 39.5 mass% or less based on the mass of the molded body. The molded product according to claim 2, wherein   The molded object as described in any one of Claims 1-3 which contains iron and the content rate of the said iron is 0.005 mass% or more and 6 mass% or less.   The molded product according to any one of claims 1 to 4, further comprising inorganic fibers, wherein the content of the inorganic fibers is 0.1% by mass or more and 50% by mass or less.   The molded body according to claim 5, wherein the inorganic fiber has biosolubility.   An enveloping body comprising: the molded body according to any one of claims 1 to 6; and an outer jacket material that houses the molded body.   The enveloping body of Claim 7 in which the said jacket material contains an inorganic fiber.   The encapsulant according to claim 7, wherein the covering material is a resin film. It is a manufacturing method of the fabrication object according to any one of claims 1 to 6,
The manufacturing method of a molded object provided with the process of heat-processing the inorganic mixture which contains a silica and germanium and whose content rate of the said germanium is 10 mass ppm or more and 1000 mass ppm or less at the temperature of 600 degreeC or more. Containing an inorganic mixture containing silica and germanium, wherein the germanium content is 10 mass ppm or more and 1000 mass ppm or less; and
A molding step of molding the inorganic mixture,
The said formation process is a manufacturing method of a molded object which has the following process (a) or process (b).
(A) The process of heating to 600 degreeC or more, pressing the said inorganic mixture with the said shaping | molding die.
(B) A step of performing heat treatment at a temperature of 600 ° C. or higher after forming the inorganic mixture by pressurization. In the forming step, the bulk density of the molded body is set the molding pressure to be less than 0.25 g / cm ³ or more 2.0 g / cm ^3, the process for producing a molded article of claim 11. And small particles having an average particle diameter D _S containing silica is less than 30nm or more 5 nm, the average particle diameter D _L containing germanium and silica were mixed with large particles, which are 40nm or more 50μm or less, a step of obtaining the inorganic mixture Furthermore, the manufacturing method of the molded object of Claim 11 provided. And small particles having an average particle diameter D _S containing silica is less than 30nm or more 5 nm, and large particles having an average particle diameter D _L containing germanium and silica is 40nm or more 50μm or less, and a metal oxide sol are mixed, the The manufacturing method of the molded object of Claim 11 further equipped with the process of obtaining an inorganic mixture. Containing an inorganic mixture containing silica and germanium, wherein the germanium content is 10 mass ppm or more and 1000 mass ppm or less; and
A molding step of molding the inorganic mixture;
A cutting step of cutting a part of the molded body obtained by the molding step,
The manufacturing method of the cutting body in which the said formation process has the following process (c) or process (d).
(C) A step of heating the inorganic mixture while applying pressure by the mold 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.
(D) A step of performing heat treatment at a temperature of 600 ° C. or higher after the inorganic mixture is molded by pressurizing with the molding die.

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