Thermal insulation structure and method for manufacturing the same

Abstract

A thermal insulation structure includes a first member, a second member, a mat material, and an inorganic adhesive. The first member has a first surface that can reach a temperature of 200°C or higher. The second member has a second surface disposed opposite the first surface of the first member. The mat material is disposed between the first member and the second member. A region is formed on at least one of the first surface and the second surface, and the region includes the inorganic adhesive. The inorganic adhesive exhibits adhesive properties when heated.

Description

[Technical Field]

[0001] This disclosure relates to an insulating structure (e.g., a pollution control device) and a method for manufacturing the same. [Background technology]

[0002] Exhaust gases from automobile engines contain carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx), and other substances. Exhaust gases from diesel engines also contain particulate matter such as soot. Exhaust gas purification systems using ceramic catalytic converters or diesel particulate filters (DPFs) are known as means of removing these substances. In addition, the implementation of gasoline particulate filters (GPFs) is also being considered. These devices are collectively called pollution control devices.

[0003] Generally, contamination control devices (e.g., ceramic catalytic converters) include a contamination control element (e.g., a honeycomb-shaped catalyst carrier made of ceramic), a metal casing enclosing the contamination control element, and a retaining material filled in the gap between the outer surface of the contamination control element and the inner surface of the casing. The retaining material holds the contamination control element within the casing, preventing accidental mechanical shocks such as impacts and vibrations from being applied to the contamination control element. The retaining material also prevents the contamination control element from moving and breaking within the casing, providing the desired effect throughout the operating life of the contamination control element. This type of retaining material is generally called a mounting material. Such a retaining material is generally a mat-like material consisting of one or more layers and is used by being wrapped around the contamination control element.

[0004] In general, the holding material contains inorganic materials such as inorganic fibers as its main component, from the viewpoint of achieving excellent heat insulation and heat resistance. Such holding materials (mounting materials) are described, for example, in Japanese Patent Publication No. 57-61686(A), Japanese Patent Publication No. 2002-66331(A), and Japanese Patent Publication No. 2006-223920(A). [Overview of the project]

[0005] In the field of contamination control devices, where contamination control elements are mounted within the casing, the retaining material is designed primarily to prevent displacement during use through the compressive repulsive and frictional forces of the retaining material. Most such retaining materials exhibit a coefficient of friction in the range of 0.4 to 0.5 at 600°C on the surface that contacts either the casing or the contamination control element, or both. That is, the retaining material holds the contamination control element in place by compressive repulsive forces against the surfaces of other members in contact with it (i.e., the inner surface of the casing and / or the outer surface of the contamination control element), preventing the contamination control element from moving out of its predetermined position after it has been sealed together with the contamination control element within the casing.

[0006] An object of this disclosure is to provide an insulating structure for use in heated environments. The insulating structure comprises a first member and a second member, wherein a mat material is disposed between the first member and the second member to insulate one member from the other. An inorganic adhesive is used to suppress relative displacement of one or both of the mat material and members during use of the structure in a heated environment. Another object of this disclosure is to provide a method for manufacturing such an insulating structure. An additional object of this disclosure is to provide one or more uses of such structures (e.g., contamination control devices).

[0007] One aspect of the present disclosure relates to a thermal insulation structure. The thermal insulation structure includes a first member, a second member, a mat material, and an inorganic adhesive. The first member has a first surface whose temperature may reach 200°C or higher. The second member has a second surface disposed opposite to the first surface of the first member. The mat material is disposed between the first member and the second member. A region is formed on at least one of the first surface and the second surface, and the region includes an inorganic adhesive. The inorganic adhesive exhibits adhesion when heated.

[0008] Another aspect of the present disclosure relates to an insulating structure in the form of a contamination control device. In such an insulating structure, a first member is a contamination control element, a second member is a casing, the contamination control element is provided within the casing, and a mat material is disposed between the casing and the contamination control element.

[0009] An additional aspect of the present disclosure relates to a method for manufacturing a thermal insulation structure. The method includes providing a first member having a first surface whose temperature may reach 200°C or higher, providing a second member having a second surface disposed opposite to the first surface of the first member, coating at least a portion of at least one of the first surface and the second surface with a solution containing an inorganic adhesive, and drying the solution to substantially dry and bond the inorganic adhesive to at least a portion of at least one of the first surface and the second surface.

[0010] According to this disclosure, an apparatus or structure for use in a heated environment is provided in which relative movement between its components can be completely prevented or significantly suppressed. [Brief explanation of the drawing]

[0011] [Figure 1] This is a perspective view showing one embodiment of a mat material that may be used in this disclosure. [Figure 2] This is a schematic cross-sectional view showing one embodiment of a contamination control device according to the present disclosure. [Figure 3] This is a schematic cross-sectional view of a contamination control element or casing of the contamination control device shown in Figure 2, having the surface layer according to this disclosure. [Figure 4] This is a cross-sectional view schematically showing the thermal insulation structure according to this disclosure. [Figure 5] This photograph shows a portion of the mat material (using aluminum phosphate as an inorganic adhesive) fixed or bonded to the inner surface of the casing. [Figure 6] This photograph shows a portion of the mat material (using sodium silicate as an inorganic adhesive) fixed or bonded to the outer surface of the catalyst support. DESCRIPTION OF EMBODIMENTS

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0013] FIG. 1 is a perspective view showing an example of a mat material configured to be wound around a pollution control element 30 having an outer shape of a circular cylinder or an elliptical cylinder, and to mount and insulate the pollution control element 30 in a casing 20 (see FIG. 2). The mat material 10 has a length that matches the length of the outer circumference of the pollution control element 30. For example, the mat material 10 has a convex portion 10a at one end and a concave portion 10b at the other end, and when the mat material 10 is wound around the pollution control element 30, the convex or tongue portion 10a and the concave or groove portion 10b are shaped to fit into each other. It should also be noted that other shapes such as an L shape are possible, and the shape for fitting is not particularly limited.

[0014] As shown in Fig. 3, the surface layer 5 (region containing an inorganic adhesive) is provided on the first surface 34 of the first member 30 (for example, the outer surface of the contamination control element 30), on the second surface 24 of the second member 20 (for example, the inner surface of the contamination control apparatus casing 20), or on both the surface 34 and the surface 24. It may be desirable for each surface layer 5 to have a thickness in the range of about 5 to about 15 mm. The mat material 10 (see, for example, Fig. 2) is disposed between the member surface 24 and the member surface 34, and each adhesive surface layer 5 is disposed between the mat material and the corresponding member. The mat material 10 comprises inorganic fibers that can have a diameter (for example, an average diameter) in the range of about 3 to about 10 µm. The mat material may also contain other components formulated as needed. Each surface layer 5 comprises an inorganic adhesive that exhibits adhesiveness when heated, and optionally other components formulated as needed. It is to be noted that the surface layer 5 is present only on one surface of the corresponding member. Alternatively, the surface layer 5 may be present on only a portion or part of a region of one surface or both of the surfaces 24 and 34. In addition, although Fig. 3 shows a state where the surface layer 5 is laminated and adhered to one or both of the surface 24 and the surface 34, each surface layer 5 is also adhered to and impregnated into the main body portion of the mat material 10.

[0015] As described above, the surface layer 5 contains an inorganic adhesive that exhibits adhesion when heated. The inorganic adhesive described herein provides adhesion not only through the formation of reaction products with other members when heated, but also through the fluidity exhibited by the inorganic adhesive of the surface layer 5 when heated, and the fixing effect (fixed state or bonded state) obtained by penetration into the contact surface of the mat material 10 or other members. The temperature at which adhesion is exhibited is not limited, but for example, adhesion is exhibited at 200°C or higher, 300°C or higher, or 600°C or higher. For example, the mat material 10 is placed sandwiched between two members and left for 1 hour under a temperature of 600°C. Then, the mat material 10 exhibits adhesion to the other members. Adhesion can be visually determined by checking whether a fixed area or bonded area is formed between the mat material 10 and one member or the other member, or both members, after the heated mat material 10 has cooled (see Figures 5 and 6). Such adhesion can result in a mat material 10 exhibiting a coefficient of friction of 0.75 or higher at 600°C on the surface that contacts one or both of the first and second members.

[0016] While the inorganic adhesive is generally in a liquid state at normal temperatures, the surface layer 5 is substantially dry on the corresponding structural member (e.g., member 20 or 30). In this specification, "substantially dry" refers to a dry state obtained, for example, by a drying process after coating with the inorganic adhesive, in which the mass loss rate after heating the mat material 10 at 120°C for 30 minutes is within approximately 5% based on the mass of the mat material 10 before heating. Because the surface layer 5 is substantially dry, it has the advantage of excellent workability when assembling the components (e.g., members) of the thermal insulation structure or device.

[0017] The inorganic adhesive described above is, for example, at least one salt selected from the group consisting of alkali metal salts, alkaline earth metal salts, and phosphates. Specific examples of alkali metal salts include alkali metal silicates such as sodium silicate, potassium silicate, and lithium silicate. Specific examples of alkaline earth metal salts include alkaline earth metal silicates such as magnesium silicate and calcium silicate. Specific examples of phosphates include aluminum phosphate, magnesium phosphate, and calcium phosphate. One of these components may be used alone, or a combination of two or more may be used.

[0018] The liquid containing the inorganic adhesive may be coated onto either the surface of the structural members 20 and 30, and then a drying process may be carried out to form the surface layer 5. The content of the inorganic adhesive (the salt) in the surface layer 5 may be, for example, 1 g / m². 2 ~50g / m 2 Therefore, 2g / m 2 ~40g / m 2 , or 5g / m 2 ~30g / m 2 This may also be the case. The amount of inorganic adhesive in the surface layer 5 can be appropriately set according to the required adhesion of the mat material 10 to the desired members 20 and / or 30.

[0019] The surface layer 5 may contain inorganic colloidal particles. Various fine particles of inorganic materials can be used to form the inorganic colloidal particles, but preferred inorganic materials include metal oxides, nitrides, carbides, and heat-resistant materials. For example, preferred examples include, but are not limited to, silica, alumina, mullite, zirconia, magnesia, and titania. Other examples of preferred materials include boron nitride and boron carbide. These inorganic materials can be used individually or in combination of two or more.

[0020] The inorganic colloidal particles described above can be used with various particle sizes depending on the type of inorganic material and the desired friction improvement effect, but it is generally preferable that they have an average particle size of about 1 to 100 nm. If the inorganic colloidal particles have an average particle size of less than 1 nm, such inorganic colloidal particles cannot form a friction layer that can contribute to the friction-increasing effect. In contrast, if the inorganic colloidal particles have an average particle size greater than 100 nm, the particles may fall off because they are too large to adequately contribute to the increase in friction. The average particle size of the inorganic colloidal particles is more preferably in the range of about 10 to 80 nm, and most preferably in the range of about 20 to 50 nm. With respect to inorganic colloidal particles, refer to International Publication No. 2007 / 030410, which is incorporated herein by reference in its entirety.

[0021] Inorganic adhesives may also contain clay (kaolin), boehmite, titanium dioxide, fumed silica, fumed alumina, precipitated silica, ATH, and other suitable common fillers to modify viscosity and absorption properties. Inorganic adhesives may also contain humectants such as glycerin, sorbitol, other sugar alcohols, and ethylene glycol. These materials may help plasticize the inorganic adhesive to improve handling properties. Suitable dyes and pigments may also be incorporated to help locate the inorganic adhesive. Suitable surfactants may also be included to help wet the surface to be bonded.

[0022] The surface layer 5 may further contain inorganic fibers as needed. The diameter of the inorganic fibers may be about 1 nm to about 15 nm, for example, about 1 nm or more, about 2 nm or more, or about 3 nm or more, and may be about 15 nm or less, about 8 nm or less, or about 5 nm or less. Inorganic fibers with a diameter of about 1 nm or more have the advantage of being easily available compared to inorganic fibers thinner than 1 nm. In addition, such inorganic fibers tend to suppress the scattering of fiber fragments during the manufacture of contamination control devices. On the other hand, inorganic fibers with a diameter of about 15 nm or less tend to suppress the generation of fiber fragments during the manufacture of devices compared to inorganic fibers thicker than about 15 nm. The average length of the inorganic fibers may be, for example, about 500 to about 5000 nm, or about 1000 to about 4000 nm, or about 1400 to about 3000 nm.

[0023] The diameter (average diameter) and average length (average fiber length) of inorganic fibers can be determined, for example, by measuring the thickness and length of 50 or more fibers randomly sampled from a microscope image (TEM image, SEM image, etc.) and calculating the average value. The aspect ratio of the inorganic fiber is calculated by dividing the average length by the diameter.

[0024] The average length of the inorganic fibers mentioned above may be, for example, about 60 to about 2000 nm, about 100 to about 1500 nm, or about 300 to about 800 nm. Inorganic fibers with an aspect ratio of about 60 or more tend to suppress the scattering of fiber fragments during device manufacturing compared with inorganic fibers with an aspect ratio of less than about 60. On the other hand, inorganic fibers having an aspect ratio of about 2000 or less have the advantage of being easily usable compared with inorganic fibers with an aspect ratio greater than about 2000. For more information on inorganic fibers, please refer to Japanese Patent Publication No. 2017-210815.

[0025] The main body of the mat material can be mainly composed of inorganic fibers. Specific examples of inorganic fibers constituting the main body of the mat material include glass fibers, ceramic fibers, carbon fibers, silicon carbide fibers, boron fibers, etc., but other inorganic fibers can be used as needed. One type of inorganic fiber selected from the above list may be used alone, or a combination of two or more types may be used. In addition, the inorganic fibers may be used in the form of composite fibers. Particularly preferred are ceramic fibers such as alumina fibers, silica fibers, and alumina-silica fibers. One type of ceramic fiber may be used alone, or a combination of two or more types may be used. In addition, the ceramic fibers may be used in the form of composite fibers. An expanding material such as unexpanded vermiculite may also be contained within the main body of the mat material at a concentration of approximately 5 to approximately 50% by weight of the total weight of the main body.

[0026] The main body of the mat material mainly consists of inorganic fibers and optionally contains organic binders as additives. There are two representative manufacturing methods for producing the mat material: a dry process and a wet process.

[0027] In the dry process, for example, an alumina fiber precursor is obtained by spinning a sol-gel containing a mixture of an alumina source such as aluminum oxychloride, a silica source such as silica sol, an organic binder such as polyvinyl alcohol, and water. Afterward, the alumina fiber precursor is laminated into a sheet, then the laminate is needle-punched, and the main body is fired at a high temperature in the range of approximately 1000-1300°C. The needle-punching density is, for example, approximately 1 punch / cm². 2 ~50 punches / cm 2By changing this density, the thickness, bulk density, and strength of the mat can be adjusted. On the other hand, in the wet process, the main body is obtained by continuously performing steps such as mixing inorganic fibers as starting materials and an organic binder with any additive, followed by opening the inorganic fibers, preparing a slurry, papermaking, and pressing into a mold. For details on the wet process (wet lamination process), refer to International Publication No. 2004 / 061279 and U.S. Patent No. 6,051,193, which are incorporated herein by reference. Note that the type and amount of organic binder used are not particularly limited. For example, acrylic resins, styrene-butadiene resins, acrylonitrile resins, polyurethane resins, natural rubber, polyvinyl acetate resins, etc., provided in the form of latex, may be used as organic binders. Alternatively, thermoplastic resins such as unsaturated polyester resins, epoxy resins, and polyvinyl ester resins may be used as organic binders.

[0028] A method for manufacturing an embodiment of a thermal insulation structure includes providing one or both of the members 20 and 30, coating at least one or both of the first surface 24 of the first member 20 or the second surface 34 of the second member 30 with a liquid containing an inorganic adhesive, and applying heat to the liquid after it has been coated as described above. According to the above manufacturing method, one or each of the structural members can be obtained, having a surface layer 5 formed on at least one of its surfaces.

[0029] If the mat material contains inorganic fine particles, it may be preferable in step (a) to adjust the composition of the colloidal solution so that the content of fine particles is about 1 to about 10% by mass based on the total mass of the main body. If the inorganic fine particle content is about 1% by mass or more, sufficient surface pressure can be easily obtained, and if the inorganic fine particle content is about 10% by mass or less, then sufficient surface pressure can be obtained. If the adhesive is not adhered to it, the mat material 10 may have sufficient flexibility to more easily conform to the surface of the member (for example, wrapped around a contamination control element).

[0030] It should be noted that the step of drying the structural member coded with the colloidal solution is performed as necessary. It should also be noted that such drying of the colloidal solution can be performed together with other drying steps. For example, it can be combined with the drying step of an inorganic adhesive carried out after the step of forming the surface layer 5. Alternatively, such a step can be combined with a drying step after coating another solution. Drying of the colloidal solution is performed, for example, for about 10 to about 180 minutes in a hot air dryer set at about 80 to about 250°C.

[0031] The liquid used for forming the surface layer 5 contains an inorganic adhesive and components (inorganic fibers and / or inorganic fine particles) that are blended as necessary. Coating of the liquid onto the surface of the main body may be performed by, for example, spray coating, roll coating, film transfer, curtain coating, or the like. In one embodiment, the coating amount per unit area (mass of solid content) is, for example, about 1 g / m 2 to about 200 g / m 2 may be within the range of . Furthermore, in one embodiment, the coating amount may also be about 10 g / m 2 to about 175 g / m 2 may be within the range. The coating amount may also be about 20 g / m 2 to about 150 g / m 2 may be within the range. The coating amount per unit area (mass of solid content) may be, for example, about 1 g / m 2 to about 400 g / m 2 may be within the range. The coating amount per unit area may be about 50 to about 350 g / m 2 , about 100 to about 300 g / m 2 , or about 150 to about 250 g / m 2It may be desirable for the range to be within this range. The drying process after coating is for forming the surface layer 5 by evaporating the water. For example, the structural members 20 and / or 30 after coating with the solution can be dried in a hot air dryer set to about 75 to about 250°C for about 10 to about 180 minutes. This forms the surface layer 5 on the surface of the corresponding members. The coating of the inorganic adhesive may be any desired form on the surface of the members, such as stripes, dots, or any other desired design pattern.

[0032] The process of forming the surface layer 5 may be divided into multiple steps. For example, first, a liquid containing an inorganic adhesive may be coated onto the surface of the corresponding member, and then a liquid containing other components may be coated onto the surface of the corresponding member. The order may also be reversed, that is, first, a liquid containing other components may be coated onto the surface of the corresponding member, and then a liquid containing an inorganic adhesive may be coated onto the surface of the corresponding member. The inorganic adhesive may be applied to either a wet or dry member.

[0033] As shown in Figure 2, the mat material 10 is used to mount the pollution control element 30 inside the pollution control device 50. Specific examples of the pollution control element 30 include catalyst carriers and filter elements for purifying exhaust gas from an engine. Specific examples of the pollution control device 50 include catalytic converters and exhaust purification devices (e.g., diesel particulate filter devices). The pollution control device 50 includes a casing 20, a pollution control element 30 provided inside the casing 20, and a mat material 10 disposed between the inner surface of the casing 20 and the outer surface of the pollution control element 30. The pollution control device 50 further includes a gas inlet 21 for introducing exhaust gas into the pollution control element 30, and a gas outlet 22 through which the exhaust gas that has passed through the pollution control element 30 is discharged.

[0034] In the contamination control device 50, the mat material 10 is arranged sandwiched between the inner surface of the casing 20 and the outer surface of the contamination control element 30. The width of the gap between the inner surface of the casing 20 and the outer surface of the contamination control element 30 is preferably about 1.5 to about 15 mm, from the viewpoint of ensuring airtightness and reducing the amount of mat material 10 used. The mat material 10 is preferably in a properly compressed state, and when heated, the mat material 10 can be fixed or bonded to other members that come into contact with it. In one embodiment, the mat material 10 is fixed to the inner surface of the casing 20 and to the outer surface of the contamination control element 30, so that displacement of the contamination control element 30 within the contamination control device 50 can be suppressed to a high extent. In addition, the bulk density of the mat material can be set lower compared to mat materials in related technologies, and therefore the amount of relatively expensive inorganic fiber material used can be reduced. Examples of techniques for compressing and assembling the mat material 10 include clamshell technology, stuffing technology, and tourniquet technology.

[0035] The pollution control element 30 reaches a high temperature when high-temperature exhaust gas passes through it. The portion between the pollution control element 30 and the mat material 10 is heated to a high temperature of 200 to 1100°C. On the other hand, the portion between the mat material 10 and the casing 20 is heated to a high temperature of 100 to 800°C. Since the pollution control device 50 includes a mat material 10 having a surface layer 5 that exhibits adhesiveness when heated, the pollution control element 30 can be firmly held within the casing 20. The catalyst supported by the catalyst carrier is generally a metal (e.g., platinum, ruthenium, osmium, rhodium, iridium, nickel, and palladium) and a metal oxide (e.g., vanadium pentoxide and titanium dioxide), and is preferably used in the form of a coating. It should be noted that the pollution control device can be configured as a diesel particulate filter or a gasoline particulate filter by applying a filter element instead of a catalyst carrier.

[0036] While embodiments of the present disclosure have been described in detail, the present invention is not limited to the above embodiments. For example, although the above embodiments were described as examples of applying the mat material 10 to a pollution control device, the mat material 10 may be applied to any other thermal insulation structure including a heat source, such as an exhaust manifold and exhaust pipe, or an exhaust gas system component through which a hot fluid flows, and a heat shield cover installed around it. As briefly shown in Figure 4, the thermal insulation structure 60 includes a first member 61 (e.g., a heat source or exhaust gas system component through which a hot fluid flows) having a surface 61a through which a temperature may reach 200°C or higher, a second member 62 (e.g., a heat shield cover) having a surface 62a facing the surface 61a of the first member 61, and a mat material 10 disposed between the first member 61 and the second member 62. The heat from the first member 61, which may raise its temperature to 200°C or higher, induces an inorganic adhesive on the surface 61a to exhibit adhesion between the first member 61 and the mat material 10. The heat from the first member 61, if located on the surface 62a, can also induce the formation of an inorganic adhesive on the surface 62a, causing the temperature of the surface 62a to rise above 200°C, resulting in adhesion between the second member 62 and the mat material 10. The adhesion of the inorganic adhesive can suppress displacement of the mat material 10 within the thermal insulation structure 60.

[0037] Additional Embodiments 1. A thermal insulation structure comprising a first member, a second member, a mat material, and an inorganic adhesive. The first member has a first surface whose temperature may reach 200°C or higher. The second member has a second surface disposed opposite to the first surface of the first member. The mat material is disposed between the first member and the second member. A region is formed on at least one of the first surface and the second surface, and the region contains the inorganic adhesive. The inorganic adhesive exhibits adhesion when heated. Preferably, the inorganic adhesive exhibits only adhesion (i.e., sufficient tackiness to form an adhesive bond on the member surface) when heated to a temperature above room temperature (i.e., above 24°C) or ambient temperature (i.e., in the range of 24°C to 46°C). It may be desirable that the inorganic adhesive exhibits only adhesion when heated to temperatures of at least 50°C, 75°C, 100°C, 125°C, 150°C, 175°C, 200°C or higher. 2. The thermal insulation structure according to Embodiment 1, wherein the inorganic adhesive is substantially dry. 3. The thermal insulation structure according to Embodiment 1 or 2, wherein the inorganic adhesive contains at least one salt selected from the group consisting of alkali metal salts, alkaline earth metal salts, and phosphates. 4. The thermal insulation structure according to Embodiment 3, wherein the alkali metal salt is an alkali metal silicate. 5. The thermal insulation structure according to Embodiment 4, wherein the alkali metal silicate is at least one selected from the group consisting of sodium silicate, potassium silicate, and lithium silicate. 6. The thermal insulation structure according to Embodiment 3, wherein the phosphate is at least one selected from the group consisting of aluminum phosphate, magnesium phosphate, and calcium phosphate. 7. The salt content is 1 g / m² in the region containing inorganic adhesive. 2 ~50g / m 2 The thermal insulation structure described in Embodiment 3. 8. The thermal insulation structure according to any one of embodiments 1 to 7, wherein a region containing an inorganic adhesive is formed on both the first surface and the second surface. 9. The thermal insulation structure according to any one of embodiments 1 to 8, wherein a region containing an inorganic adhesive is formed on the entire surface of at least one of the first surface and the second surface. 10. The thermal insulation structure according to any one of embodiments 1 to 8, wherein a region containing an inorganic adhesive is formed on a portion of at least one of the first surface and the second surface. 11. The thermal insulation structure according to any one of Embodiments 1 to 10, wherein the region containing the inorganic adhesive contains inorganic colloidal particles. 12. The thermal insulation structure according to Embodiment 11, wherein the inorganic colloidal particles are alumina colloidal particles. 13. The thermal insulation structure according to any one of Embodiments 1 to 12, wherein the mat material contains inorganic fibers having an aspect ratio of 60 to 2000. The thermal insulation structure according to Embodiment 13, wherein the inorganic fiber having an aspect ratio of 14.60 to 2000 is an alumina fiber. 15. The thermal insulation structure according to any one of embodiments 1 to 14, wherein after heating an inorganic adhesive at a temperature of 600°C for 1 hour, a fixing area is formed between the first surface of the first member and the mat material, between the mat material and the second surface of the second member, or both. 16. The thermal insulation structure according to any one of embodiments 1 to 15, wherein a fixed area is formed between the first surface of the first member and the mat material after heating the inorganic adhesive under a temperature condition of at least about 100 to 150°C for at least about 10 minutes. 17. The thermal insulation structure according to any one of embodiments 1 to 16, wherein the fixing area is formed between the mat material and the second surface of the second member after heating the inorganic adhesive under a temperature condition of at least about 100 to 150°C for at least about 10 minutes. 18. Salt content is 1 g / m² in the region containing inorganic adhesive. 2 ~400g / m 2 The thermal insulation structure described in any one of embodiments 3 to 14. 19. The thermal insulation structure according to any one of embodiments 1 to 18, wherein the thermal insulation structure is a contamination control device, the first member is a contamination control element, the second member is a casing, the contamination control element is provided inside the casing, and a mat material is disposed between the casing and the contamination control element. 20. The thermal insulation structure according to Embodiment 19, wherein after heating the inorganic adhesive at a temperature of 600°C for 1 hour, fixed areas are formed between the inner surface of the casing and the outer surface of the mat material, between the inner surface of the mat material and the outer surface of the contamination control element, and both. 21. The thermal insulation structure according to Embodiment 19 or 20, wherein the inorganic adhesive is heated for at least about 10 minutes under temperature conditions of at least about 100 to 150°C, after which a fixed area is formed between the inner surface of the casing and the outer surface of the mat material. 22. The thermal insulation structure according to any one of embodiments 19 to 21, wherein the inorganic adhesive is heated for at least about 10 minutes under temperature conditions of at least about 100 to 150°C, after which a fixed area is formed between the inner surface of the mat material and the outer surface of the contamination control element. 23. A method for manufacturing an insulating structure, comprising: (a) providing a first member having a first surface whose temperature may reach 200°C or higher; (b) providing a second member having a second surface disposed opposite to the first surface of the first member; (c) coating at least a portion of at least one of the first surface and the second surface with a solution containing an inorganic adhesive; and (d) drying the solution to substantially dry and bond the inorganic adhesive to at least a portion of at least one of the first surface and the second surface. 24. The method according to Embodiment 23, wherein the inorganic adhesive exhibits adhesive properties when heated. 25. The method according to Embodiment 23 or 24, further comprising arranging a mat material between the first surface of the first member and the second surface of the second member, and bringing the mat material into contact with at least a portion of the dry inorganic adhesive. 26. The method according to Embodiment 23 or 24, further comprising arranging a mat material between the first surface of a first member and the second surface of a second member, wetting the inorganic adhesive before drying, and bringing the mat material into contact with at least a portion of the wet inorganic adhesive. 27. The method according to any one of embodiments 23 to 25, further comprising heating an inorganic adhesive to bond a mat material to at least one of a first surface and a second surface. [Examples]

[0038] This disclosure will be described with reference to its embodiments. Needless to say, the present invention is not limited to these embodiments.

[0039] Fabrication of the main body The following chemical substances were introduced into 10 L of water while stirring at 1-minute intervals to prepare a colloidal solution containing an organic binder and inorganic fine particles. (1) Aluminum sulfate (aqueous solution with a solid content of 40%): 6g (2) Organic binder (Acrylic Latex LX874 (trade name) available from Nippon Zeon): 2.6g (3) Colloidal silica (Snowtex O (product name) available from Nissan Chemical): 10g (4) Liquid sodium aluminate (solids content 40%): 3.5g

[0040] A needle-punched alumina fiber blanket (Maftec MLS-2 Blanket, available from Mitsubishi Chemical) was cut to 15cm x 40cm. This was placed on a metal mesh, and the colloidal solution was poured over it. The water was then removed by suction on the metal mesh for 15 seconds. After impregnating the blanket with the colloidal solution in this way, a drying process was carried out in a hot air dryer set to 170°C for 45 minutes. This created the main body of the mat material.

[0041] aqueous solution containing inorganic adhesive Aqueous solution 1: An aqueous solution of sodium silicate (sodium silicate No. 3, available from Fuji Chemical) was prepared by diluting it to a concentration of 50%. Aqueous solution 2: An aqueous solution of aluminum phosphate (WR-100B, available from Taki Chemical) was prepared by diluting it to a concentration of 50%.

[0042] Example 1 Aqueous solution 1 (sodium silicate aqueous solution) is coated onto the first surface (outer surface) of the contamination control element as follows: Aqueous solution 1 is applied to the entire area of ​​the first surface at a concentration of 20 g / m² (calculated as solid content). 2 The coating is spray-coated up to the specified amount. Then, a drying process is carried out for 5 minutes in a hot air dryer set to a temperature of 170°C. This forms an area containing inorganic adhesive over the entire surface of the first surface. In the same manner as above, an area containing inorganic adhesive is also formed over the entire surface (inner surface) of the second surface of the casing.

[0043] Example 1a The amount of aqueous solution 1 (sodium silicate aqueous solution) coating on the first surface and the second surface (calculated in terms of solid content) is 20 g / m² each. 2 Instead, 2g / m 2 Except for the above, the component according to this embodiment is manufactured in the same manner as in Example 1.

[0044] Example 1b The amount of aqueous solution 1 (sodium silicate aqueous solution) coating on the first surface and the second surface (calculated in terms of solid content) is 20 g / m² each. 2 Instead, 40g / m 2 Except for the above, the component according to this embodiment is manufactured in the same manner as in Example 1.

[0045] Example 2 The component according to this embodiment is prepared in the same manner as in Example 1, except that aqueous solution 2 (aluminum phosphate aqueous solution) is used instead of aqueous solution 1 (sodium silicate aqueous solution).

[0046] Comparative Example 1 This example is the same as Example 1, except that it does not contain any region containing an inorganic adhesive.

[0047] Evaluation of adhesion when heated The mat materials of the above examples and comparative examples were evaluated as follows to determine whether they exhibited adhesive properties when heated. The mat material was cut to a width of 75 mm and a length of 350 mm and wrapped around the outer circumference of a cylindrical catalyst support member (HONEYCERAM (product name), available from NGK Insulators) having a length of 115 mm and an outer diameter of 105 mm. This was then pressed into a cylindrical stainless steel casing member having a length of 150 mm and an inner diameter of 114 mm at a rate of 40 mm / second using a guide cone. After heating the converter sample thus prepared at 600°C for 1 hour, the catalyst support was withdrawn so as not to cause displacement between the mat material and the casing. Subsequently, the sample with a portion of the mat material fixed to the inner surface of the casing was evaluated as having adhesive properties to the casing. The results are shown in Table 1. Note that Figure 5 is a photograph showing the state in which a portion of the mat material is fixed to the inner surface of the casing.

[0048] After heating the converter samples prepared in the same manner as described above at 600°C for 1 hour, they were withdrawn from the casing, taking care to prevent misalignment of the mat material and catalyst support. Subsequently, samples with a portion of the mat material fixed to the outer surface of the catalyst support were evaluated for their adhesion to the catalyst support. The results are shown in Table 1. Note that Figure 6 is a photograph showing the state in which a portion of the mat material is fixed to the outer surface of the catalyst support.

[0049] [Table 1]

[0050] Example 3 A colloidal solution was prepared by diluting alumina sol AS520 (available from Nissan Chemical, solid content: 20% by mass) with water to a solid content concentration of 5% by mass. This colloidal solution was coated onto the first surface (carrier-side surface) of the first component as described below. Aqueous solution 1 was measured using a Spray Gun PS-9513 (trade name, available from Anest Iwata) at a solid content level of 5 g / m². 2 The first surface was coated with the coating amount shown. Then, in the same manner as in Example 1, aqueous solution 1 (sodium silicate aqueous solution) was added at a rate of 20 g / m² in terms of solid content. 2 The first surface was spray-coated with the specified coating amount. Then, a drying process was carried out for 5 minutes in a hot air dryer set to a temperature of 170°C. This formed a region containing inorganic fibers and inorganic adhesive over the entire surface of the first surface. A region containing inorganic adhesive was also formed on the second surface of the second component in the same manner as described above.

[0051] Example 4 Except for changing the order in which the above-mentioned colloidal solution (alumina sol aqueous solution) and aqueous solution 1 (sodium silicate aqueous solution) were sprayed, that is, the colloidal solution (alumina sol aqueous solution) was sprayed after aqueous solution 1 (sodium silicate aqueous solution), the regions containing the inorganic adhesive were formed on the first surface of the first member and the second surface of the second member in the same manner as in Example 3.

[0052] Measurement of the force required to extract the catalyst support. The force required to extract the catalyst support was measured on the mat material according to Examples 1-4 and Comparative Example 1, as described below. A heater was installed to heat the outer surface of a cylindrical catalyst support member (HONEYCERAM (product name), available from NGK Insulators) having a length of 115 mm and an outer diameter of 105 mm. The mat material was cut to a width of 75 mm and a length of 350 mm and wrapped around the outer circumference of the catalyst support member. This was then pressed into a cylindrical stainless steel casing member having a length of 150 mm and an inner diameter of 114 mm at a rate of 40 mm / second using a guide cone. After 24 hours of press-fitting, it was heated, and the temperature between the catalyst support and the mat material reached 900°C, and the temperature between the mat material and the casing reached 600°C. After these temperatures were reached, the force (N) was measured when the catalyst support was pulled out of the stainless steel casing at a rate of 40 mm / second. From the maximum force (N) measured, the force required to extract the catalyst support (N / cm) was calculated. 2 The force per unit area of ​​the mat material was calculated. The results are shown in Table 2.

[0053] [Table 2]

[0054] Example 5 Aqueous solution 1 (sodium silicate aqueous solution) is coated onto the first surface of the first component as follows: The aqueous solution is applied to the surface at a rate of 20 g / m² (calculated as solid content). 2 The coating was applied dropwise until the specified coating amount was reached. Droplets were deposited across the width of rows with spacing between rows of 1 / 2 inch and spacing between dots of 1 / 2 inch. A drying process was then carried out for 5 minutes in a hot air dryer set to a temperature of 170°C. This formed areas containing the inorganic adhesive with separate droplets uniformly distributed over the entire surface of the first component. In the same manner as above, areas containing the inorganic adhesive were formed with separate droplets uniformly distributed over the entire surface of the second component.

[0055] In Example 5, both surfaces were coated, but it is also possible that only the first or second surface could be coated. The amount applied to the surface may differ from the amount described in Example 5. The distance between rows of dots may also vary somewhere between, for example, about 1 / 4 inch and about 2 inches.

[0056] Example 6 Aqueous solution 1 (sodium silicate aqueous solution) was coated onto the first surface of the first component as follows: The aqueous solution was applied to the surface at a concentration of 20 g / m² (calculated as solid content). 2 The coating was applied in stripes up to the specified coating amount. The stripes were deposited over a width with a 1 / 2-inch gap between them. A drying process was then carried out for 5 minutes in a hot air dryer set to a temperature of 170°C. This formed the inorganic adhesive-containing areas as separate stripes uniformly distributed across the entire surface of the first member. In the same manner as above, the inorganic adhesive-containing areas were formed as separate stripes uniformly distributed across the entire surface of the second member.

[0057] In Example 6, both surfaces were coated, but it is also conceivable that only the first or second surface could be coated. The amount applied to the surface may differ from the amount described in Example 6. The distance between the stripes may also vary somewhere between, for example, about 1 / 4 inch and about 2 inches. Furthermore, while the stripes in Example 6 are assumed to be straight lines, non-linear stripes are also conceivable. For example, the stripes may be zigzag or applied as a sine wave, etc.

[0058] Example 7 A needle-punched alumina fiber blanket (3M 1600HTE 1474 basis weight, available from 3M Company, St. Paul MN) was cut to 84cm x 520cm.

[0059] The adhesive solution was prepared by mixing 950 grams of PQ type N sodium silicate, available from PQ Corporation Valley Forge PA, 50 grams of glycerin, and 1 gram of Acid Blue AE03, available from Clariant Corporation Muttenz Switzerland.

[0060] The adhesive solution was sprayed onto the first and second surfaces of the first and second components using a 3M 16570 Accuspray Model HG18 Spray Gun equipped with a 2 mm fluid tip. Three separate samples were coated with 66, 132, and 273 grams per square meter of wet adhesive. After drying in a 75°C oven for 45 minutes, the dry coating weights were 32, 64, and 139 grams per square meter, respectively.

[0061] For each coated sample, a mat material sample was cut to 44.5 × 44.5 mm. Both sides of a piece of 316 stainless steel shim (0.05 × 50 × 150 mm), part number 3316-002-12-100, available from Maudlin Products, were coated and evenly aligned between the two mat material samples, with the adhesive coating on one side of the stainless steel shim facing one of the mat material samples. The sample / shim / sample assembly was placed between two heated 44.5 × 44.5 mm platens (with horizontal grooves to prevent slippage) at a pressure of 10 psi (68.9 kPa) and held at the stated temperature for 10 minutes. After 10 minutes, the shim was removed from the assembly at 100 mm / min (pulled vertically) while recording the force. Evidence of bond formation (presence of adhesive or fibers on the shim, or separation of the sample) was observed. Refer to Table 3 for the results for each temperature setting and adhesive coating weight (gsm). The force in Table 3 is in pounds-force. Note that once the bonding point is determined, it is not necessary to test the entire temperature range.

[0062] [Table 3]

[0063] Example 8 Preparation of the binding solution: A homogeneous solution was obtained by mixing 95% by weight of sodium silicate type N from PQ Corporation with 5% by weight of glycerin. Support mat: 3M Company 1650HTG 1250 GSM Base material: Cordillerate, Diameter: 3.66 inches, Length: 3 inches Shell: Material: 409 SS

[0064] Sample preparation for the Accelerated Robustness Test: 1) Bonding solution applied to the substrate: The liquid bonding solution was applied to the outer surface of the substrate and air-dried at room temperature. The weight of the substantially dried bonding solution was 2.5 grams. 2) Bonding solution applied to the metal shell: The liquid bonding solution was applied to the inner surface of the metal shell and air-dried at room temperature. The weight of the substantially dried bonding solution was 4.75 grams. 3) Bonding solution applied to the substrate and shell: The liquid bonding solution was applied to the outer surface of the substrate and air-dried at room temperature. The weight of the substantially dried bonding solution was 2.5 grams. The liquid bonding solution was applied to the inner surface of the metal shell and air-dried at room temperature. The weight of the substantially dried bonding solution was 4.75 grams. 4) Binding solution applied to the shell side of the support mat: The liquid bonding solution was applied to the surface of the support mat in contact with the shell, and then air-dried at room temperature. The weight of the substantially dried bonding solution was 5.0 grams. 5) The binding solution applied to the substrate side of the support mat: The liquid bonding solution was applied to the surface of the support mat in contact with the substrate, and then air-dried at room temperature. The weight of the substantially dried bonding solution was 5.0 grams. 6) The binding solution applied to both the substrate side and the shell side of the support mat: The liquid solution was applied to both sides of the support mat and then air-dried at room temperature. The weight of the substantially dried binding solution was 5.0 grams per side of the support mat. 7) Control support mat. Without binder (i.e., inorganic adhesive).

[0065] Sizing: Swage the shell to obtain a support mat mount density of 0.25 g / cc. (Bonding material not included)

[0066] A vertical accelerated robustness test will be performed on each sample. The time to failure and the vibration intensity level at the time of failure will be recorded.

[0067] result: 1) A substantially dry binder applied to a substrate. Time until damage: 16:19 Vibration intensity level: 5 2) A substantially dry binder applied to the shell. Time until damage: 20:16 Vibration intensity level: 6 3) A substantially dry binder applied to the shell and substrate. Time until damage: 25:00 Vibration intensity level: 6 4) A substantially dry binder applied to the shell side of the support mat. Time until damage: 20:16 Vibration intensity level: 6 5) A substantially dry binder applied to the substrate side of the support mat. Time until damage: 21:16 Vibration intensity level: 5 6) A substantially dry binder applied to both sides of the support mat. Time until damage: 25:33 Vibration intensity level: 6 7) Control (unbound) Time until damage: 16:25 Vibration intensity level: 5 Note: Vibration intensity level 6 is twice as strong as vibration intensity level 5.

[0068] Applying a binder (i.e., an inorganic adhesive) to the shell side exhibits superior performance compared to applying it to the substrate side. Applying the binder to both sides yields the best results. Similar performance improvements are observed when any substantially dry binder is applied to the support mat, or to the substrate and / or shell. In particular, significant robustness is demonstrated compared to the control when the bond is formed between the shell and the support mat, especially when the bond is formed on both sides of the support mat.

[0069] According to this disclosure, a mat material is provided that can be applied to an apparatus or structure used in a heated environment, and the mat material can suppress displacement between the mat material and other components in contact with it during use.

Claims

1. A contamination control element having a first surface whose temperature may reach 200°C or higher, A casing comprising a second surface disposed opposite to the first surface of the contamination control element, A mat material disposed between the first surface of the contamination control element and the second surface of the casing, The system comprises a substantially dry inorganic adhesive that exhibits adhesion upon heating, present on one or both of the first surface of the contamination control element and the second surface of the casing, The inorganic adhesive contains at least one alkali metal silicate selected from the group consisting of sodium silicate, potassium silicate, and lithium silicate, but does not contain silane, siloxane, silanol, silazane, or silsesquioxane. The inorganic adhesive is configured to exhibit adhesive properties when heated, thereby bonding the contamination control element to the mat material and the casing to the mat material. A contamination control device having a heat insulating structure, wherein the mat material exhibits a coefficient of friction of 0.75 or higher at 600°C on the surface that contacts one or both of the first surface of the contamination control element and the second surface of the casing.

2. The contamination control device according to claim 1, wherein when the inorganic adhesive is heated at a temperature of 600°C for 1 hour, a fixed area is formed between the first surface of the contamination control element and the mat material, between the mat material and the second surface of the casing, or both.

3. The salt content is 1 g / m² in the region where the inorganic adhesive is present. ２ ~400g / m ２ The contamination control device according to claim 1 or 2.

4. A method for manufacturing a contamination control device having an insulating structure, To provide a contamination control element having a first surface whose temperature may reach 200°C or higher, To provide a casing comprising a second surface disposed opposite to the first surface of the contamination control element, A solution containing an inorganic adhesive is coated onto both the first surface of the contamination control element and the second surface of the casing. The solution is dried to substantially dry and bond the inorganic adhesive to both the first surface of the contamination control element and the second surface of the casing. Subsequently, the process includes placing a mat material between the first surface of the contamination control element and the second surface of the casing, and bringing the mat material into contact with the dried and bonded inorganic adhesive, The inorganic adhesive contains at least one alkali metal silicate selected from the group consisting of sodium silicate, potassium silicate, and lithium silicate, but does not contain silane, siloxane, silanol, silazane, or silsesquioxane. The inorganic adhesive exhibits adhesive properties when heated, thereby bonding the contamination control element to the mat material and the casing to the mat material. Manufacturing method.

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