A cast sheet and a method for manufacturing a cast sheet

Abstract

The present invention provides a papermaking pad and a manufacturing method thereof, which has a high initial surface pressure and maintains the surface pressure even when repeatedly compressed. A papermaking pad is composed of two or more different inorganic fibers, organic matter, and inorganic matter, characterized in that the inorganic fibers include alumina fibers (AF) and refractory ceramic fibers (RCF), and the inorganic fibers are composed of the alumina fibers at 10 wt% to 30 wt% and the refractory ceramic fibers at 70 wt% to 90 wt%.

Description

Technical Field

[0001] This invention relates to papermaking mats and methods for manufacturing papermaking mats. Background Technology

[0002] Exhaust gases from internal combustion engines such as diesel engines contain particulate matter (PM), and in recent years, the harmful effects of PM on the environment and human health have become a concern. Furthermore, since exhaust gases also contain harmful gases such as CO, HC, and NOx, there are also concerns about the impact of these harmful gases on the environment and human health.

[0003] Therefore, various exhaust gas purification devices have been proposed as exhaust gas purification devices for capturing PM or purifying harmful gas components in exhaust gases. These devices include: an exhaust gas treatment body made of porous ceramics such as silicon carbide or cordierite, a shell housing the exhaust gas treatment body, and a retaining and sealing material (shielding material) disposed between the exhaust gas treatment body and the shell. This retaining and sealing material (shielding material) is mainly provided for the following purposes: to prevent the exhaust gas treatment body from contacting the shell covering its periphery and being damaged due to vibrations or impacts caused by vehicle movement, etc.; to prevent exhaust gas from leaking out between the exhaust gas treatment body and the shell; etc.

[0004] As such a pad material, Patent Document 1 discloses a non-expansive pad containing high-temperature resistant amorphous inorganic fibers for preparing a support for brittle structures in a low-temperature exhaust gas treatment device, which contains alumina / silica fibers having about 50% Al2O3 and about 50% SiO2.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Publication No. 2002-531720 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] The alumina / silica fiber described in Patent Document 1, containing approximately 50% Al2O3 and approximately 50% SiO2, is a type of fiber known as refractory ceramic fiber. Pads made from such refractory ceramic fibers suffer from low surface pressure, and the exhaust gas treatment unit is prone to detachment due to exhaust gas pressure.

[0010] This invention was made to solve the above-mentioned problems. The purpose of this invention is to provide a papermaking pad with high initial surface pressure and the ability to maintain surface pressure even when subjected to repeated compression.

[0011] Methods for solving problems

[0012] That is, the papermaking mat of the present invention is a papermaking mat composed of two or more different kinds of inorganic fibers, organic materials and inorganic materials, characterized in that the inorganic fibers include alumina fibers (AF) and refractory ceramic fibers (RCF), and the inorganic fibers are composed of alumina fibers of 10wt% to 30wt% and refractory ceramic fibers of 70wt% to 90wt% by weight.

[0013] Alumina fibers are hard; if the padding material is made of alumina fibers, the initial surface pressure of the padding material will be high. On the other hand, refractory ceramic fibers are easy to bend; if the padding material made of refractory ceramic fibers is repeatedly compressed, the refractory ceramic fibers will bend, and the surface pressure will decrease.

[0014] On the other hand, refractory ceramic fibers are soft, and if the pad material is made of refractory ceramic fibers, the initial surface pressure of the pad material will be reduced.

[0015] The fabrication pad of the present invention comprises alumina fiber and refractory ceramic fiber, thus achieving a balance between the effect of alumina fiber in increasing the initial surface pressure of the pad material and the effect of refractory ceramic fiber in maintaining the surface pressure of the pad material under repeated compression.

[0016] Therefore, the forming pad of the present invention has a high initial surface pressure and can maintain surface pressure even when subjected to repeated compression.

[0017] In the papermaking pad of the present invention, the inorganic fibers are composed of 10wt% to 30wt% of the alumina fibers and 70wt% to 90wt% of the refractory ceramic fibers by weight.

[0018] If the weight ratio of alumina fiber and refractory ceramic fiber is within the above range, a balance is achieved between the two, which can appropriately exert the effect of high initial surface pressure and maintain surface pressure even under repeated compression.

[0019] In the fabrication pad of the present invention, it is preferable that, when randomly selecting any of the above-mentioned inorganic fibers to determine whether they are alumina fibers or refractory ceramic fibers, the number of alumina fibers is 3% or more, and the number of refractory ceramic fibers is less than 97%.

[0020] If the ratio of alumina fiber to refractory ceramic fiber is within the above range, a balance is achieved, which can appropriately exert the effect of high initial surface pressure and maintain surface pressure even under repeated compression.

[0021] In the fabrication pad of the present invention, preferably, the organic material is an organic binder and the inorganic material is an inorganic binder.

[0022] Organic and inorganic binders bond the inorganic fibers together, maintaining the shape of the papermaking mat.

[0023] In addition, it can prevent inorganic fibers from falling off and scattering from the papermaking pad.

[0024] In the papermaking pad of the present invention, the glass transition temperature Tg of the above-mentioned organic binder is preferably below 5°C.

[0025] If the glass transition temperature (Tg) of the above-mentioned organic binder is below 5°C, the strength of the organic binder film formed by the organic binder can be improved, and a papermaking pad with high film elongation and excellent flexibility can be made.

[0026] In the fabrication pad of the present invention, the organic binder is preferably selected from at least one of the following groups: acrylic resins that function as water-soluble organic polymers, acrylic latexes, rubber latexes, carboxymethyl cellulose and polyvinyl alcohol, styrene resins that function as thermoplastic resins, and epoxy resins that function as thermosetting resins.

[0027] Furthermore, in the papermaking pad of the present invention, the inorganic binder preferably includes at least one selected from the group consisting of alumina, silicon dioxide, silicon carbide, zirconium oxide, boron nitride, diamond and pumice.

[0028] These organic and inorganic binders are suitable for bonding inorganic fibers together and maintaining the shape of the papermaking mat.

[0029] The papermaking mat of the present invention is preferably manufactured by the following steps: a fiber opening step, in which an inorganic fiber molded body is opened in water to produce a slurry containing the opened inorganic fibers; and a papermaking step, in which the above slurry is papermade to produce a papermaking mat.

[0030] During the fiber opening process, multiple inorganic fibers are interwoven to form a fiber bundle.

[0031] Such fiber bundles function as core material, thus increasing the surface pressure of the forming pad.

[0032] In the papermaking pad of the present invention, the inorganic fiber molded body preferably includes a first inorganic fiber molded body from the needle-punched pad and / or a second inorganic fiber molded body from the papermaking pad.

[0033] Regardless of whether the inorganic fiber molded body comes from needle-punched pads or papermaking pads, it can form fiber bundles during the fiber opening process.

[0034] It should be noted that the first inorganic fiber molded body preferably includes the alumina fiber.

[0035] In addition, the second inorganic fiber molded body mentioned above preferably includes the refractory ceramic fiber mentioned above.

[0036] The copying pad of the present invention is preferably a copying pad obtained by copying in the above-mentioned copying process using batch copying or continuous copying.

[0037] The copying pad of the present invention can be easily obtained by performing batch copying or continuous copying.

[0038] The papermaking mat of the present invention preferably comprises a fiber bundle formed by interlacing 10 or more of the above-mentioned inorganic fibers in a twisted manner, wherein at least one of the fiber bundles is a coiled fiber bundle, and the drawn length of the coiled fiber bundle, as measured by the following drawing length measurement method, is at least 0.1 mm longer than the length of the coiled fiber bundle.

[0039] Methods for measuring the length of a drawing:

[0040] The coiled fiber bundle is placed still on a flat surface;

[0041] Observe the coiled fiber bundle from above after it has been left to stand. Draw a line along the coiled fiber bundle from one end to the other end. The distance of this line is taken as the "drawing length of the coiled fiber bundle".

[0042] The coiled fiber bundles are elastic, and the surface pressure of the papermaking pad containing such fiber bundles becomes higher.

[0043] The papermaking mat of the present invention preferably further comprises organic fibrils as the aforementioned organic material.

[0044] It should be noted that the above-mentioned organic fibrils are preferably fibrillated by fibrillating cellulose, acrylic acid, aromatic polyamide, and PVA to create a fuzzy morphology at the fiber ends and on the surface.

[0045] The papermaking mat manufacturing method of the present invention is a method for manufacturing a papermaking mat composed of two or more different inorganic fibers, organic materials and inorganic materials, characterized in that the inorganic fibers include alumina fibers (AF) and refractory ceramic fibers (RCF), and the papermaking mat manufacturing method includes a papermaking step: papermaking a slurry containing the alumina fibers (AF) and the refractory ceramic fibers (RCF) to form a papermaking mat, wherein the inorganic fibers are composed of alumina fibers in a weight ratio of 10wt% to 30wt% and refractory ceramic fibers in a weight ratio of 70wt% to 90wt%.

[0046] The papermaking pad of the present invention can be manufactured using the papermaking pad manufacturing method of the present invention.

[0047] In the manufacturing method of the papermaking mat of the present invention, the inorganic fibers are composed of the above-mentioned alumina fibers in a weight ratio of 10wt% to 30wt% and the above-mentioned refractory ceramic fibers in a weight ratio of 70wt% to 90wt%.

[0048] If the weight ratio of alumina fiber and refractory ceramic fiber is within the above range, a balance is achieved, enabling the manufacture of a papermaking pad with high initial surface pressure that can maintain surface pressure even under repeated compression.

[0049] In the manufacturing method of the papermaking pad of the present invention, it is preferable that when randomly selecting any inorganic fiber from the slurry to determine whether it is alumina fiber or refractory ceramic fiber, the number of alumina fibers is 3% or more, and the number of refractory ceramic fibers is less than 97%.

[0050] If the ratio of alumina fiber to refractory ceramic fiber is within the above range, a balance is achieved, enabling the manufacture of a papermaking pad with high initial surface pressure that can maintain surface pressure even under repeated compression.

[0051] The preferred method for manufacturing the papermaking mat of the present invention includes a fiber splitting process: splitting the inorganic fiber molded body containing the above-mentioned alumina fiber and the above-mentioned refractory ceramic fiber in water to prepare a slurry.

[0052] By performing a fiber opening process, a fiber bundle is formed by the interweaving of multiple inorganic fibers.

[0053] Such fiber bundles function as core material, thus increasing the surface pressure of the manufactured paper pad.

[0054] In the method for manufacturing the papermaking pad of the present invention, the inorganic fiber molded body preferably includes a first inorganic fiber molded body from the needle-punched pad and / or a second inorganic fiber molded body from the papermaking pad.

[0055] Regardless of whether the inorganic fiber molded body comes from needle-punched pads or papermaking pads, it can form fiber bundles during the fiber opening process.

[0056] It should be noted that the first inorganic fiber molded body preferably includes the alumina fiber.

[0057] In addition, the second inorganic fiber molded body mentioned above preferably includes the refractory ceramic fiber mentioned above.

[0058] In the method for manufacturing the papermaking pad of the present invention, it is preferable that the slurry in the above-mentioned papermaking process contains organic fibrils as the above-mentioned organic material.

[0059] Furthermore, in the manufacturing method of the papermaking mat of the present invention, it is preferable that, in the above-mentioned fiber opening process, the organic fibrils are opened in water to produce the above-mentioned slurry.

[0060] Invention Effects

[0061] According to the present invention, a papermaking pad with high initial surface pressure and which can maintain surface pressure even when subjected to repeated compression can be provided. Attached Figure Description

[0062] Figure 1 This is a perspective view schematically illustrating an example of the papermaking pad of the present invention.

[0063] Figure 2 This is an enlarged view schematically illustrating an example of the inorganic fibers of a papermaking pad containing fiber bundles, according to the present invention.

[0064] Figure 3 This is a schematic diagram of an example of a coiled fiber bundle.

[0065] Figure 4 This is a schematic cross-sectional view illustrating an example of the exhaust gas purification device of the present invention. Detailed Implementation

[0066] The following is a detailed description of the printing pad of the present invention. However, the present invention is not limited to the following configuration, and can be appropriately modified and applied without changing the essential points of the present invention. It should be noted that a configuration obtained by combining two or more of the preferred configurations of the present invention described below is also the present invention.

[0067] The printing pad of the present invention will be illustrated with reference to the accompanying drawings.

[0068] Figure 1 This is a perspective view schematically illustrating an example of the papermaking pad of the present invention.

[0069] like Figure 1 As shown, the papermaking mat 10 is a rectangular papermaking mat made of inorganic fibers.

[0070] The forming pad 10 has a rectangular shape when viewed from above, with a protrusion 11a at one end 11 and a recess 12a at the other end 12.

[0071] Details are described below. The fabricated pad 10 is wound around the exhaust gas treatment body and installed in the exhaust gas purification device.

[0072] The protrusions 11a and the recesses 12a are shapes that fit together perfectly when the forming pad 10 is wound onto the exhaust gas treatment body.

[0073] If such a protrusion 11a and a recess 12a are provided, the sealing performance is improved when the fabrication pad 10 is placed in the exhaust gas purification device described later.

[0074] The forming pad 10 contains an organic binder as an organic material and an inorganic binder as an inorganic material.

[0075] Organic and inorganic binders bond the inorganic fibers together, maintaining the shape of the forming pad 10.

[0076] In addition, it can suppress the inorganic fibers from falling off and scattering from the forming pad 10.

[0077] In addition, the papermaking mat 10 may also contain organic fibrils composed of cellulose, acrylic acid, aramid, PVA, etc. as organic materials.

[0078] Organic fibrils undergo fibrillation from the ends and surface to form microfibrils (fibrils), which in turn intertwine with inorganic fibers to improve their tightness.

[0079] The organic fibrils are preferably in the form of fine fibers that are fuzzy at the ends and on the surface of the fibers composed of the above-mentioned organic materials.

[0080] In the forming pad 10, the inorganic fibers include alumina fibers (AF) and refractory ceramic fibers (RCF).

[0081] In addition, inorganic fibers can also include other inorganic fibers besides alumina fibers and refractory ceramic fibers. Examples of other inorganic fibers include silica fibers, glass wool, and rock wool.

[0082] In this specification, "alumina fiber" refers to fiber in which the weight percentage of Al2O3 constituting the fiber exceeds 60% by weight.

[0083] In this specification, "refractory ceramic fiber" refers to fiber in which the weight percentage of Al2O3 constituting the fiber is less than 60% by weight.

[0084] As alumina fiber, fibers containing Al2O3 and SiO2 are preferred, with the weight ratio of Al2O3:SiO2 being 70:30 to 80:20.

[0085] As a refractory ceramic fiber, fibers containing Al2O3 and SiO2 are preferred, and the preferred weight ratio is Al2O3:SiO2 = 40:60 to 60:40.

[0086] Alumina fibers are hard; if the padding material is made of alumina fibers, the initial surface pressure of the padding material will be high. On the other hand, refractory ceramic fibers are easy to bend; if the padding material made of refractory ceramic fibers is repeatedly compressed, the refractory ceramic fibers will bend, and the surface pressure will decrease.

[0087] On the other hand, refractory ceramic fibers are soft, and if the pad material is made of refractory ceramic fibers, the initial surface pressure of the pad material will be reduced.

[0088] The fabrication pad 10 contains alumina fibers and refractory ceramic fibers, thus achieving a balance between the initial surface pressure improvement effect of alumina fibers and the surface pressure maintenance effect of refractory ceramic fibers when the pad is subjected to repeated compression.

[0089] Therefore, the initial surface pressure of the printing pad 10 is high, and the surface pressure can be maintained even when subjected to repeated compression.

[0090] In the papermaking pad 10, the inorganic fibers are preferably composed of alumina fibers of 5 wt% or more and refractory ceramic fibers of less than 95 wt%, and more preferably composed of alumina fibers of 10 wt% to 30 wt% and refractory ceramic fibers of 70 wt% to 90 wt%.

[0091] If the weight ratio of alumina fiber and refractory ceramic fiber is within the above range, a balance is achieved between the two, which can appropriately exert the effect of high initial surface pressure and maintain surface pressure even under repeated compression.

[0092] It should be noted that, if it is desirable to improve the softness of the papermaking mat 10, the weight ratio of alumina fiber is preferably less than 30 wt%, and if it is desirable to harden the papermaking mat 10, the weight ratio of alumina fiber is preferably 30 wt% or more.

[0093] In the fabrication pad 10, when randomly selecting any of the above-mentioned inorganic fibers to determine whether they are alumina fibers or refractory ceramic fibers, it is preferable that the number of alumina fibers is 3% or more and the number of refractory ceramic fibers is less than 97%, more preferably that the number of alumina fibers is 20% to 50% and the number of refractory ceramic fibers is 50% to 80%.

[0094] If the ratio of alumina fiber to refractory ceramic fiber is within the above range, a balance is achieved, which can appropriately exert the effect of high initial surface pressure and maintain surface pressure even under repeated compression.

[0095] In the papermaking mat 10, relative to 100 parts by weight of inorganic fibers, it preferably contains 0.1 to 20 parts by weight of organic binder, more preferably 0.5 to 10 parts by weight.

[0096] In addition, relative to 100 parts by weight of inorganic fiber, it is preferable to include 0.1 to 10 parts by weight of inorganic binder, more preferably 0.5 to 3.0 parts by weight.

[0097] Organic and inorganic binders bond the inorganic fibers together, maintaining the shape of the papermaking mat.

[0098] If the contents of organic and inorganic binders are within the above range, the adhesion between inorganic fibers becomes moderate, which can balance the softness and shape retention of the papermaking mat.

[0099] In the forming pad 10, the glass transition temperature Tg of the organic binder is preferably below 5°C, and more preferably -35°C to 5°C.

[0100] If the glass transition temperature (Tg) of the organic binder is below 5°C, the strength of the organic binder film formed by the organic binder can be improved, and a papermaking pad with high film elongation and excellent flexibility can be made.

[0101] Furthermore, the mat is less prone to cracking when it is wound around the exhaust gas treatment unit. Moreover, since the organic binder coating does not become too rigid, it can maintain the inorganic fibers in place even if they break, thus preventing fiber scattering.

[0102] Organic binders with a glass transition temperature (Tg) of less than -50°C are expensive, increasing manufacturing costs.

[0103] When the glass transition temperature (Tg) of an organic binder exceeds 5°C, the flexibility and elongation at break of the sheet material may decrease.

[0104] In the fabrication pad of the present invention, the organic binder can be a water-soluble organic polymer, a thermoplastic resin, or a thermosetting resin.

[0105] Examples of water-soluble organic polymers include acrylic resins, acrylate latexes, rubber latexes, carboxymethyl cellulose, and polyvinyl alcohol. Examples of thermoplastic resins include styrene resins. Examples of thermosetting resins include epoxy resins.

[0106] In the forming pad 10, the inorganic binder preferably includes at least one selected from the group consisting of alumina, silicon dioxide, silicon carbide, zirconium oxide, boron nitride, diamond and pumice.

[0107] These organic and inorganic binders are suitable for bonding inorganic fibers together to maintain the shape of the papermaking mat.

[0108] The papermaking pad 10 may contain a fiber bundle formed by interlacing more than 10 of the above-mentioned inorganic fibers in a twisted manner.

[0109] The accompanying drawings illustrate a papermaking pad containing such fiber bundles.

[0110] Figure 2 This is an enlarged view schematically illustrating an example of the inorganic fibers of a papermaking pad containing fiber bundles, according to the present invention.

[0111] like Figure 2 As shown, the papermaking mat may contain fiber bundles 21 formed by interlacing 10 or more inorganic fibers 20 in a twisted manner, and inorganic fibers 22 that do not constitute fiber bundles 21.

[0112] Fiber bundle 21 can be in a straight state ( Figure 2 The state represented by the symbol "21a" can also be a coiled state. Figure 2 The state represented by the symbol "21b" in the middle.

[0113] In this specification, fiber bundles refer to the parts of the papermaking mat where inorganic fibers are concentrated and interwoven, and where the density is higher than that of other parts.

[0114] The average length of fiber bundle 21 ( Figure 2 The average length (represented by the symbol L) is preferably 5mm to 15mm, more preferably 7mm to 13mm, and even more preferably 8mm to 10mm.

[0115] The average width of fiber bundle 21 ( Figure 2 The average length (represented by the symbol W) is preferably 0.2 mm to 1.0 mm, more preferably 0.2 mm to 0.8 mm.

[0116] It should be noted that, as Figure 2 As shown, in both the case of fiber bundle 21a in a straight state and the case of fiber bundle 21b in a coiled state, this is its maximum width ( Figure 2 In the figure, the lengths represented by the symbols Wa and Wb respectively are the width of fiber bundle 21.

[0117] Fiber bundles 21 are formed by interlacing 10 or more inorganic fibers 20 in a twisted manner, supporting each other and therefore not easily deformed by pressure. Therefore, when pressure is applied to the papermaking mat, the fiber bundles 21 function as a core material, mitigating pressure on the inorganic fibers 22 that do not form fiber bundles 21. This prevents the inorganic fibers 22 that do not form fiber bundles 21 from bending under pressure. As a result, the surface pressure of the papermaking mat increases.

[0118] In particular, when the fiber bundle 21 is in a coiled state, this effect is appropriately achieved, and the surface pressure of the papermaking pad is further increased.

[0119] If the average length of the fiber bundle is less than 5 mm, the fiber bundle is too short and cannot serve as a core material to mitigate the pressure applied to the inorganic fibers that do not constitute the fiber bundle.

[0120] If the average length of the fiber bundle exceeds 15mm, the fiber bundle is too long and therefore easily bends when pressed on the side, making it difficult to function as a core material.

[0121] If the average width of the fiber bundle is less than 0.2 mm, the strength of the fiber bundle will decrease, the fiber bundle will be easily bent, and it will be difficult to function as a core material.

[0122] If the average width of the fiber bundle exceeds 1.0 mm, the strength of the fiber bundle becomes too high, and the overall softness of the papermaking mat decreases.

[0123] Here, the coiled fiber bundle 21b will be described in detail with reference to the accompanying drawings.

[0124] Figure 3 This is a schematic diagram of an example of a coiled fiber bundle.

[0125] exist Figure 3 Of the coiled fiber bundles 21b shown, the drawing length L of the coiled fiber bundles 21b, as measured by the following drawing length measurement method, is preferably... t The length L of the fiber bundle 21b in the coiled state is longer than that of the fiber bundle in the coiled state, more preferably 0.1 mm or more, and even more preferably 0.2 mm to 0.6 mm.

[0126] (Methods for measuring the length of a drawing)

[0127] The coiled fiber bundle 21b is placed on a flat surface.

[0128] Next, observe the coiled fiber bundle 21b from above after it has been left to rest. Draw a line along the coiled fiber bundle 21b from one end P1 to the other end P2, and measure the distance L of the line drawn. t As "the drawing length of the fiber bundle in its coiled state".

[0129] When the length L of the coiled fiber bundle 21b is drawn... t When the length L of the fiber bundle 21b in the coiled state is longer than that in the coiled state, the elasticity of the fiber bundle 21b in the coiled state becomes higher, and the surface pressure of the forming pad 10 increases.

[0130] The forming pad 10 preferably comprises fiber bundles 21b in a curled state as follows: Figure 3 In the coiled fiber bundle 21b shown, when measuring the “drawing length of the coiled fiber bundle”, the coiled fiber bundle 21b can be drawn by crossing the line segment S connecting end P1 and end P2 more than twice.

[0131] The degree of curling of the fiber bundle 21b in this curled state is appropriate, the elasticity of the curled fiber bundle 21b is increased, and the surface pressure of the forming pad 10 is increased.

[0132] In the forming pad 10, the preferred drawing length L of the coiled fiber bundle 21b is... t The ratio of the length L of the fiber bundle 21b in its coiled state to that of the other fiber bundle is L. t / L = 1.1 to 1.6.

[0133] In the papermaking pad 10, the value of the following formula (1) is preferably 0.1 or more, and more preferably 0.2 to 0.6.

[0134] (L t -L) / Wb…(1)

[0135] It should be noted that "Wb" refers to the width of the fiber bundle 21b in its coiled state.

[0136] In the forming pad 10, the coiled fiber bundle 21b is placed on a flat surface, and the area of ​​the coiled fiber bundle 21b as viewed from above is preferably 2.6 mm². 2 ~8.3mm 2 .

[0137] In the papermaking pad 10, the proportion of the number of coiled fiber bundles 21b included in the fiber bundle 21 is preferably 85% or less, more preferably 60% or less, further preferably 30% or less, and even more preferably 10% to 30%.

[0138] The fiber bundle 21 is formed by the interlacing of multiple inorganic fibers 20, which support each other and are therefore not easily deformed by pressure. Therefore, when pressure is applied to the forming pad 10, the fiber bundle 21 functions as a core material, mitigating pressure on the inorganic fibers 22 that do not form the fiber bundle 21. This prevents the inorganic fibers 22 that do not form the fiber bundle 21 from bending under pressure. As a result, the surface pressure of the forming pad 10 increases.

[0139] Next, an example of the method for manufacturing the paper-making pad of the present invention will be described.

[0140] An example of the manufacturing method of the papermaking pad of the present invention described below includes (1) a fiber opening process and (2) a papermaking process. Each process will be described below.

[0141] (1) Fiber opening process

[0142] In this process, the inorganic fiber molded body containing alumina fiber and refractory ceramic fiber is split in water to make slurry.

[0143] Because the slurry contains alumina fibers and refractory ceramic fibers, the pads manufactured in subsequent processes can achieve a balance between the initial surface pressure improvement effect of alumina fibers and the surface pressure maintenance effect of refractory ceramic fibers under repeated compression.

[0144] Therefore, the manufactured paper pad has a high initial surface pressure and can maintain surface pressure even when subjected to repeated compression.

[0145] It should be noted that, in the above-mentioned slurry, the inorganic fibers are preferably composed of alumina fibers of 5 wt% or more and refractory ceramic fibers of less than 95 wt%, and more preferably composed of alumina fibers of 10 wt% to 30 wt% and refractory ceramic fibers of 70 wt% to 90 wt%.

[0146] If the weight ratio of alumina fiber and refractory ceramic fiber is within the above range, a balance is achieved between the two, which can appropriately exert the effect of high initial surface pressure and maintain surface pressure even under repeated compression.

[0147] In addition, when randomly selecting any of the inorganic fibers in the above slurry to determine whether they are alumina fibers or refractory ceramic fibers, it is preferable that the number of alumina fibers is 3% or more and the number of refractory ceramic fibers is less than 97%, more preferably that the number of alumina fibers is 20% to 50% and the number of refractory ceramic fibers is 50% to 80%.

[0148] If the ratio of alumina fiber to refractory ceramic fiber is within the above range, a balance is achieved, enabling the manufacture of a papermaking pad with high initial surface pressure that can maintain surface pressure even under repeated compression.

[0149] In addition, during the opening of the inorganic fiber molded body, the inorganic fibers are not completely opened, forming a fiber bundle composed of multiple inorganic fibers interwoven together.

[0150] Such fiber bundles function as core material, thus increasing the surface pressure of the manufactured paper pad.

[0151] In the method for manufacturing the papermaking pad of the present invention, the inorganic fiber molded body preferably includes a first inorganic fiber molded body from the needle-punched pad and / or a second inorganic fiber molded body from the papermaking pad.

[0152] Regardless of whether the inorganic fiber molded body comes from needle-punched pads or paper-making pads, it can form fiber bundles 21 during the fiber opening process.

[0153] It should be noted that the first inorganic fiber molded body preferably includes the alumina fiber.

[0154] In addition, the second inorganic fiber molded body mentioned above preferably includes the refractory ceramic fiber mentioned above.

[0155] As an example of fiber opening, the following methods can be cited.

[0156] First, the first inorganic fiber molded body and / or the second inorganic fiber molded body are fired at 700°C to 1000°C for 1.0 hour to 8.0 hours. The preferred firing temperature is 800°C to 950°C.

[0157] Therefore, the organic binder contained in the inorganic fiber molded body can be thermally decomposed, making it easier for the inorganic fiber molded body to open.

[0158] Next, let the fired inorganic fiber molded body stand at room temperature, and then unravel the inorganic fiber molded body by hand.

[0159] Next, the inorganic fiber molded body is added to water in a weight ratio of 50 to 400, and stirred to open the fibers, thereby producing a slurry containing inorganic fibers. This weight ratio is preferably 100 to 200.

[0160] Furthermore, the mixing conditions should preferably be set appropriately. For example, when preparing 10L of slurry, it is preferable to use a mixer (product name: SMT-101, manufacturer: AS ONE) at a speed of 500–1000 rpm and a mixing time of 200–900 seconds. A speed of 650–850 rpm and a mixing time of 500–700 seconds are preferred, and a speed of 700–800 rpm and a mixing time of 500–650 seconds are even more preferred.

[0161] Next, organic and inorganic binders are added to the slurry.

[0162] The organic binder is preferably added to the manufactured paper mat in an amount of 0.1 to 20 parts by weight relative to 100 parts by weight of inorganic fibers, and more preferably in an amount of 0.5 to 15.0 parts by weight.

[0163] The inorganic binder is preferably added to the manufactured paper mat at a ratio of 0.1 to 10 parts by weight relative to 100 parts by weight of inorganic fibers, and more preferably at a ratio of 0.5 to 3.0 parts by weight.

[0164] The preferred types of organic and inorganic binders have already been described, so the description is omitted here.

[0165] (2) Copying process

[0166] Next, slurry is poured into a molding apparatus with a filter screen on the bottom surface, and the solvent in the slurry is desoldered to obtain inorganic fiber aggregates. Then, the inorganic fiber aggregates are dehydrated and dried.

[0167] It should be noted that during the papermaking process, the inorganic fiber aggregates can be dried by heating and pressurizing. During heating and pressurizing, hot air can be circulated through the inorganic fiber aggregates for heat treatment to dry them, or they can remain in a moist state without heat treatment.

[0168] In the case of heat treatment, to prevent the organic binder from deteriorating due to heat, the heating temperature and hot air temperature are preferably between 100°C and 250°C. Within this range, the deterioration of the organic binder can be suppressed, and moisture can be dispersed from the inorganic fiber aggregates. If the heating temperature and hot air temperature are below 100°C, the temperature does not reach the center of the inorganic fiber aggregates, resulting in a longer drying time. Furthermore, if the temperature exceeds 250°C, the organic binder deteriorates, reducing the binding force between fibers, thus making it difficult to control the thickness of the inorganic fiber aggregates.

[0169] The above processes enable the fabrication pad of this invention to be manufactured.

[0170] It should be noted that, in the manufacturing method of the papermaking pad of the present invention, it is preferable to perform batch papermaking or continuous papermaking in the papermaking process.

[0171] The copying pad of the present invention can be easily obtained by performing batch copying or continuous copying.

[0172] In the above-mentioned method for manufacturing paperboard mats, the paperboard forming process is performed after the fiber opening process. However, in the method for manufacturing paperboard mats of the present invention, as long as a slurry containing alumina fibers and refractory ceramic fibers can be prepared and paperboard forming is performed to manufacture the mat material, the fiber opening process may be omitted.

[0173] Next, the method of using the papermaking pad of the present invention will be described.

[0174] Figure 4 This is a schematic cross-sectional view illustrating an example of the exhaust gas purification device of the present invention.

[0175] like Figure 4 As shown, the exhaust gas purification device 100 includes a metal housing 30, an exhaust gas treatment body 40 housed within the metal housing 30, and a forming pad 10 disposed between the exhaust gas treatment body 40 and the metal housing 30. The forming pad 10 is the forming pad of the present invention.

[0176] The exhaust gas treatment body 40 is a columnar body with multiple cells 41 arranged side by side along its length through the cell walls 42. It should be noted that, at the end of the metal casing 30, an inlet pipe for introducing exhaust gas discharged from the internal combustion engine and an outlet pipe for discharging the exhaust gas after passing through the exhaust gas purification device to the outside are connected as needed.

[0177] exist Figure 4 In the exhaust gas purification device 100 shown, as the exhaust gas treatment body 40, an exhaust gas filter (honeycomb filter) is used, which is sealed with sealing material 43 at any one of the channels. However, a catalyst carrier that is not sealed with sealing material at any end face can also be used.

[0178] like Figure 4 As shown, the exhaust gas discharged from the internal combustion engine and flowing into the exhaust gas purification device 100 ( Figure 4 In the diagram, (G represents exhaust gas, and arrows indicate the flow of exhaust gas) the exhaust gas flows into a channel 41 opened on the exhaust gas inflow side end face 40a of the exhaust gas treatment body (honeycomb filter) 40, and passes through the channel wall 42 that separates the channel 41. At this time, PM in the exhaust gas is captured by the channel wall 42, and the exhaust gas is purified. The purified exhaust gas flows out through other channels 41 opened on the exhaust gas outflow side end face 40b, and is discharged to the outside.

[0179] As described above, the initial surface pressure of the forming pad 10 is high, and it can maintain the surface pressure even when subjected to repeated compression.

[0180] Therefore, even when the exhaust gas treatment unit 40 is subjected to high pressure from the exhaust gas during the initial use of the exhaust gas purification device 100, it can prevent the exhaust gas treatment unit 40 from falling off the metal casing 30. In addition, the effect of preventing this falling off can be maintained for a long time.

[0181] The exhaust gas treatment unit 40 can be made of non-oxidizing porous ceramics such as silicon carbide or silicon nitride, or it can be made of oxidizing porous ceramics such as silane, alumina, cordierite, or mullite. Among them, silicon carbide is preferred.

[0182] When the exhaust gas treatment body 40 is a porous ceramic made of silicon carbide, the porosity of the porous ceramic is not particularly limited, but is preferably 35% to 60%.

[0183] If the porosity is less than 35%, the exhaust gas treatment body may become clogged immediately. On the other hand, if the porosity exceeds 60%, the strength of the exhaust gas treatment body may decrease and it may be easily damaged.

[0184] In addition, the average pore size of the porous ceramic is preferably 5μm to 30μm.

[0185] If the average pore size is less than 5 μm, PM can sometimes easily cause blockage.

[0186] If the average pore size exceeds 30μm, PM may sometimes pass through the pores, making it impossible to capture PM and thus preventing the filter from functioning properly.

[0187] It should be noted that the porosity and pore size mentioned above can be determined using existing known methods such as scanning electron microscopy (SEM).

[0188] The pore density in the cross-section of the exhaust gas treatment body 40 is not particularly limited, but the preferred lower limit is 31.0 pores / cm². 2 (200 pieces / inch) 2 The preferred upper limit is 93.0 pieces / cm². 2 (600 pieces / inch) 2Furthermore, a more preferred lower limit is 38.8 particles / cm². 2 (250 pieces / inch) 2 The preferred upper limit is 77.5 particles / cm². 2 (500 pieces / inch) 2 ).

[0189] The waste gas treatment unit 40 can also be loaded with a catalyst for purifying waste gas. Preferred catalysts include precious metals such as platinum, palladium, and rhodium, with platinum being more preferred. Other catalysts may include alkali metals such as potassium and sodium, and alkaline earth metals such as barium. These catalysts can be used individually or in combination of two or more.

[0190] If these catalysts are loaded, PM can be easily burned off and removed, and toxic exhaust gases can also be purified.

[0191] (Metal casing)

[0192] The metal casing 30 is approximately cylindrical.

[0193] The inner diameter of the metal casing 30 (the inner diameter of the portion that houses the exhaust gas treatment body) is preferably slightly shorter than the diameter of the exhaust gas treatment body 40 to which the forming pad 10 is wound.

[0194] The metal casing 30 is not particularly limited, but is preferably made of stainless steel.

[0195] The following matters are disclosed in this specification.

[0196] This disclosure (1) is a papermaking mat, which is a papermaking mat composed of two or more different inorganic fibers, organic materials and inorganic materials, characterized in that the inorganic fibers include alumina fibers (AF) and refractory ceramic fibers (RCF).

[0197] This disclosure (2) is a papermaking pad as described in this disclosure (1), wherein the inorganic fibers are composed of a weight ratio of 5 wt% or more of the alumina fibers and less than 95 wt% of the refractory ceramic fibers.

[0198] This disclosure (3) refers to the papermaking pad as described in disclosure (1) or (2), wherein, when randomly selecting any of the inorganic fibers from the papermaking pad to determine whether they are alumina fibers or refractory ceramic fibers,

[0199] The number of alumina fibers is 3% or more, and the number of refractory ceramic fibers is less than 97%.

[0200] This disclosure (4) is a fabrication pad as described in any one of (1) to (3) of this disclosure, wherein the organic material is an organic binder and the inorganic material is an inorganic binder.

[0201] This disclosure (5) is a paper-making pad as described in this disclosure (4), wherein the glass transition temperature Tg of the organic binder is below 5°C.

[0202] This disclosure (6) is a fabrication pad as described in disclosure (4) or (5), wherein the organic binder is selected from at least one of the following groups: acrylic resins that function as water-soluble organic polymers, acrylic latexes, rubber latexes, carboxymethyl cellulose and polyvinyl alcohol, styrene resins that function as thermoplastic resins, and epoxy resins that function as thermosetting resins.

[0203] This disclosure (7) refers to the fabrication pad as described in any one of disclosures (4) to (6), wherein the inorganic binder comprises at least one selected from the group consisting of alumina, silicon dioxide, silicon carbide, zirconium oxide, boron nitride, diamond and pumice.

[0204] The papermaking mat of this disclosure (8) as described in any one of disclosures (1) to (7) is made by the following steps: a fiber opening step in which an inorganic fiber molded body is opened in water to make a slurry containing the opened inorganic fibers; and a papermaking step in which the slurry is papermade to make a papermaking mat.

[0205] This disclosure (9) is a papermaking pad as described in this disclosure (8), wherein the inorganic fiber molded body comprises a first inorganic fiber molded body from a needle-punched pad and / or a second inorganic fiber molded body from a papermaking pad.

[0206] This disclosure (10) is a papermaking pad as described in this disclosure (9), wherein the first inorganic fiber molded body comprises the alumina fiber.

[0207] This disclosure (11) is a papermaking pad as described in this disclosure (9), wherein the second inorganic fiber molded body comprises the refractory ceramic fiber.

[0208] This disclosure (12) is a copying pad as described in disclosures (8) to (11), wherein the copying process is carried out by batch copying or continuous copying.

[0209] This disclosure (13) is a papermaking mat as described in any one of disclosures (1) to (12), wherein the papermaking mat comprises a fiber bundle formed by interlacing 10 or more of the aforementioned inorganic fibers in a twisted manner, at least one of the fiber bundles being a coiled fiber bundle, and the drawn length of the coiled fiber bundle, as measured by the following drawing length measurement method, is at least 0.1 mm longer than the length of the coiled fiber bundle.

[0210] Methods for measuring the length of a drawing:

[0211] The coiled fiber bundle is placed still on a flat surface;

[0212] Observe the coiled fiber bundle from above after it has been left to stand. Draw a line along the coiled fiber bundle from one end to the other end. The distance of this line is taken as the "drawing length of the coiled fiber bundle".

[0213] The fabricated mat of this disclosure (14) as described in any one of disclosures (1) to (13) further comprises organic fibrils as the aforementioned organic material.

[0214] This disclosure (15) is a method for manufacturing a papermaking mat, which is a method for manufacturing a papermaking mat composed of two or more different inorganic fibers, organic materials and inorganic materials, characterized in that the inorganic fibers include alumina fibers (AF) and refractory ceramic fibers (RCF), and the method for manufacturing the papermaking mat includes a papermaking step: papermaking a slurry containing the alumina fibers (AF) and the refractory ceramic fibers (RCF) to make a papermaking mat.

[0215] This disclosure (16) describes a method for manufacturing a paper-making pad as described in this disclosure (15), wherein the inorganic fibers are composed of a weight ratio of 5 wt% or more of the alumina fibers and less than 95 wt% of the refractory ceramic fibers.

[0216] This disclosure (17) describes a method for manufacturing a papermaking pad as described in disclosure (15) or (16), wherein when randomly selecting any of the inorganic fibers from the slurry to determine whether they are alumina fibers or refractory ceramic fibers, the number of alumina fibers is 3% or more, and the number of refractory ceramic fibers is less than 97%.

[0217] The method for manufacturing a paper-making mat as described in any one of the disclosures (15) to (17) further includes a fiber-opening step: opening an inorganic fiber molded body containing the above-mentioned alumina fibers and the above-mentioned refractory ceramic fibers in water to produce the above-mentioned slurry.

[0218] This disclosure (19) is a method of manufacturing a papermaking pad as described in this disclosure (18), wherein the inorganic fiber molded body comprises a first inorganic fiber molded body from a needle-punched pad and / or a second inorganic fiber molded body from a papermaking pad.

[0219] This disclosure (20) describes a method for manufacturing a paper-making pad as described in this disclosure (19), wherein the first inorganic fiber molded body comprises the alumina fiber.

[0220] This disclosure (21) is a method for manufacturing a paper-making pad as described in disclosure (19) or (20), wherein the second inorganic fiber molded body comprises the refractory ceramic fiber.

[0221] This disclosure (22) is a method for manufacturing a papermaking pad as described in disclosures (15) to (21), wherein, in the papermaking process, the slurry further comprises organic fibrils as the organic material.

[0222] Example

[0223] The following describes embodiments of the present invention in more detail. It should be noted that the present invention is not limited to these embodiments.

[0224] (Example 1)

[0225] The first inorganic fiber molded body from the needle-punched pad was prepared, which consisted of alumina fibers with an Al2O3:SiO2 ratio of 72:28 (by weight) and a bulk density of 0.17 g / mm². 3 The density of stitches is 21 per cm. 2 The density.

[0226] A second inorganic fiber molded body was prepared from the papermaking mat, which consisted of refractory ceramic fibers with an Al2O3:SiO2 ratio of 50:50 (by weight) and a bulk density of 1.2 g / mm². 3 .

[0227] Next, the first inorganic fiber molded body and the second inorganic fiber molded body are fired at 800°C for 1 hour to thermally decompose the organic binder contained in the first inorganic fiber molded body and the second inorganic fiber molded body.

[0228] Next, the fired first and second inorganic fiber molded bodies were left to stand at room temperature, and then the first and second inorganic fiber molded bodies were separated by hand.

[0229] Next, 7.0g of the first inorganic fiber molded body and 3.0g of the second inorganic fiber molded body were taken out and added to 0.4L of water. Then, the mixture was stirred using a mixer (product name: SMT-101, manufacturer: AS ONE) at a speed of 1000rpm for 10 minutes to open the fibers, thereby producing an inorganic fiber slurry.

[0230] It should be noted that when 100 inorganic fibers were randomly selected from the slurry to determine whether they were alumina fibers or refractory ceramic fibers, the results showed that the proportion of alumina fibers was 71% and the proportion of refractory ceramic fibers was 29%.

[0231] In addition, compared to 100 parts by weight of inorganic fibers, the weight ratio of alumina fibers is 70 parts by weight and the weight ratio of refractory ceramic fibers is 30 parts by weight.

[0232] Next, an organic binder is added to the slurry in a manner that is 0.5 to 10 parts by weight relative to 100 parts by weight of inorganic fibers.

[0233] In addition, an inorganic binder is added to the slurry in an amount of 0.3 to 3.0 parts by weight relative to 100 parts by weight of inorganic fibers.

[0234] Next, slurry is poured into a molding apparatus with a filter screen on the bottom surface, and the solvent in the slurry is desoldered to obtain an inorganic fiber aggregate. Then, the inorganic fiber aggregate is dehydrated and dried at 150°C to 210°C for 5 minutes to 1 hour to produce the papermaking pad of Example 1.

[0235] (Example 2), (Example 3), and (Comparative Example 1)

[0236] The first and second inorganic fiber molded bodies used were adjusted as shown in Table 1, and the ratio (weight ratio) of alumina fiber and refractory ceramic fiber was changed. Otherwise, the papermaking pads of Examples 2, 3 and Comparative Example 1 were manufactured in the same manner as in Example 1.

[0237] [Table 1]

[0238]

[0239] (Measurement of surface pressure)

[0240] The paper-making pads from Examples 1 to 3 and Comparative Example 1 were placed in a testing machine (product name: SMT-101, manufacturer: AS ONE) and compressed at a speed of 25.4 mm / min to a void bulk density (GBD) of 0.40 mm. 3 / g. With a void bulk density (GBD) of 0.40 mm². 3 The state of / g was maintained for 10 minutes. After that, the papermaking pad was released at a rate of 25.4 mm / min.

[0241] The compression and release were repeated 1000 times. Afterward, the surface pressure of each printing pad was measured.

[0242] The results are shown in Table 1.

[0243] As shown in Table 1, the surface pressure of the printing pads in Examples 1 to 3 remains high even after repeated compression and release.

[0244] Symbol Explanation

[0245] 10 copying pads

[0246] 11 One end

[0247] 11a convex part

[0248] 12 Another end

[0249] 12a recess

[0250] 20, 22 Inorganic Fibers

[0251] Fiber bundles 21, 21a, and 21b

[0252] 30 Metal Casing

[0253] 40 waste gas treatment units

[0254] 40a Exhaust gas inflow side end

[0255] 40b Exhaust Gas Discharge Side End

[0256] 41 channels

[0257] 42-hole wall

[0258] 43 Sealing Material

[0259] 100 exhaust gas purification device

Claims

1. A waste gas purification device, comprising: a metal casing, a waste gas treatment body housed within the metal casing, and a forming pad disposed between the waste gas treatment body and the metal casing, characterized in that, The paper-making mat is composed of two or more different types of inorganic fibers, organic materials, and inorganic materials. The inorganic fibers include alumina fibers (AF) and refractory ceramic fibers (RCF). The inorganic fibers are composed of alumina fibers at a weight ratio of 10wt% to 30wt% and refractory ceramic fibers at a weight ratio of 70wt% to 90wt%. The inorganic material is an inorganic binder. The papermaking pad consists of one layer.

2. The waste gas purification device as described in claim 1, wherein, When randomly selecting any inorganic fiber from the forming pad to determine whether it is alumina fiber or refractory ceramic fiber, The alumina fiber count is 3% or more, and the refractory ceramic fiber count is less than 97%.

3. The waste gas purification device as described in claim 1 or 2, wherein, The organic material is an organic binder.

4. The waste gas purification device as described in claim 3, wherein, The glass transition temperature (Tg) of the organic binder is below 5°C.

5. The waste gas purification device as described in claim 3, wherein, The organic binder is selected from at least one of the following groups: acrylic resins that function as water-soluble organic polymers, acrylate latexes, rubber latexes, carboxymethyl cellulose and polyvinyl alcohol, styrene resins that function as thermoplastic resins, and epoxy resins that function as thermosetting resins.

6. The waste gas purification device as described in claim 3, wherein, The inorganic binder comprises at least one selected from the group consisting of alumina, silicon dioxide, silicon carbide, zirconium oxide, boron nitride, diamond, and pumice.

7. The waste gas purification device as described in claim 1 or 2, wherein, The papermaking mat comprises a fiber bundle formed by interlacing more than 10 of the inorganic fibers in a twisted manner. At least one of the fiber bundles is in a coiled state. The drawn length of the coiled fiber bundle, as measured by the following drawing length measurement method, is at least 0.1 mm longer than the length of the coiled fiber bundle. Methods for measuring the length of a drawing: The coiled fiber bundle is placed still on a flat surface; Viewing the coiled fiber bundle from above after it has been left to stand, trace along the coiled fiber bundle from one end to the other, and define the distance traced as the "tracing length of the coiled fiber bundle".

8. The waste gas purification device as described in claim 1 or 2, wherein the fabrication pad further comprises organic fibrils as the organic material.

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