Paper-made mat and method for producing the same

Abstract

The present invention provides a forming mat that is not prone to cracking even after being wound around a substrate and has a sufficiently high surface pressure. The forming mat of the present invention is characterized in that it is a forming mat composed of inorganic fibers, the forming mat includes fiber bundles formed by intertwining 10 or more of the inorganic fibers in a twisted manner and the inorganic fibers that do not form the fiber bundles, the average length of the fiber bundles exceeds 5 mm, and when the forming mat is fibrillated by the following fibrillating method of the forming mat to obtain a slurry containing the inorganic fibers, the specific gravity of the inorganic fibers contained in the slurry in water is 0.012 to 0.035 g / cm<supgt;3< / supgt>. Fibrillating method of the forming mat: Heat-treat the forming mat at 600 °C for 1 hour. Unwind and weigh 5.0 g of fibers from the forming mat, put the fibers into a container containing 400 cc of water. After stirring at a rotation speed of 1000 rpm for 10 minutes, transfer it to a graduated cylinder container, and add water so that the total volume reaches 500 cc. Let it stand for 30 minutes, read the height of the settled fibers, and calculate the specific gravity in water using the following calculation formula (1). Specific gravity in water (g / cm<supgt;3< / supgt;) = 5.0 (g) / sedimentation volume of fibers (cm<supgt;3< / supgt;)... (1).

Description

Technical Field

[0001] The invention relates to a papermaking mat and a method for producing the papermaking mat. Background Art

[0002] Exhaust gas discharged from internal combustion engines such as diesel engines contains particulate matter (hereinafter also referred to as PM), and in recent years, the harm caused by PM to the environment and human body has become a problem. In addition, since the exhaust gas also contains harmful gas components such as CO, HC, and NOx, there are also concerns about the impact of these harmful gas components on the environment and human body.

[0003] Therefore, various exhaust gas purification devices have been proposed as exhaust gas purification devices for capturing PM in exhaust gas or purifying harmful gas components, which include: an exhaust gas treatment body composed of porous ceramics such as silicon carbide or cordierite, a shell for accommodating the exhaust gas treatment body, and a holding sealing material (mat) arranged between the exhaust gas treatment body and the shell. The holding sealing material (mat) is mainly arranged for the following purposes: preventing the exhaust gas treatment body from contacting with the shell covering its outer periphery and being damaged due to vibration or impact generated by the driving of the car, etc.; preventing exhaust gas from leaking from between the exhaust gas treatment body and the shell; etc.

[0004] In order to increase the force (surface pressure) of the mat member in holding the exhaust gas treatment body, Patent Document 1 discloses a mat member in which the surface pressure is increased by manufacturing an alumina fiber aggregate using a specific spinning aid.

[0005] In Patent Document 2, the holding force (surface pressure) is improved by including agglomerated fibers aggregated into agglomerates having a diameter of 1 to 5 mm and a total length of 2 to 3 mm in the paper sheet.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: International Publication No. 2018 / 012423

[0009] Patent Document 2: Japanese Patent Application Publication No. 2008-82310 Summary of the invention

[0010] Problems to be solved by the invention

[0011] The mat material described in Patent Document 1 has the problem that the alumina fibers are easily broken and the surface pressure is easily reduced.

[0012] In addition, the mats described in Patent Documents 1 and 2 are wound around the exhaust gas treating body when used, but there is a problem that cracks occur in the mats due to the difference in inner and outer circumferences of the mats during winding.

[0013] In particular, in the mat material described in Patent Document 2, the density of the inorganic fibers present between the agglomerated fibers is low, and cracks are easily generated.

[0014] In addition, since the paper-made sheet described in Patent Document 2 is a needle-punched sheet subjected to dry fiber opening, the fibers after fiber opening become shorter, and the fibers constituting the bulk coagulated fibers also become shorter. Therefore, in the bulk coagulated fibers, the fibers are not fully intertwined with each other, and the bulk coagulated fibers do not have a twisted shape. In addition, the length of the bulk coagulated fibers is also shortened. Therefore, the elasticity of the bulk coagulated fibers does not become sufficiently high, and there is a problem that the surface pressure of the manufactured paper-made sheet is difficult to become sufficiently high.

[0015] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a papermaking mat which is unlikely to crack even after being wound on a base material and has a sufficiently high surface pressure.

[0016] Means for solving problems

[0017] That is, the paper-made mat of the present invention is a paper-made mat composed of inorganic fibers, characterized in that the above-mentioned paper-made mat comprises a fiber bundle formed by interweaving 10 or more of the above-mentioned inorganic fibers in a twisted manner and the above-mentioned inorganic fibers that do not constitute the above-mentioned fiber bundle, the average length of the above-mentioned fiber bundle exceeds 5 mm, and when the above-mentioned paper-made mat is opened by the following paper-made mat opening method to obtain a slurry containing the above-mentioned inorganic fibers, the bulk specific gravity in water of the above-mentioned inorganic fibers contained in the above-mentioned slurry is 0.012 to 0.035 g / cm 3 .

[0018] Fiber opening method for making mat:

[0019] The prepared mat was heat treated at 600°C for 1 hour.

[0020] Fibers in an amount of 5.0 g were unwound and weighed from the paper mat, and placed in a container filled with 400 cc of water.

[0021] After stirring at a stirring speed of 1000 rpm for 10 minutes, the mixture was transferred to a graduated cylinder container, and water was added so that the total volume became 500 cc.

[0022] After the mixture was left to stand for 30 minutes, the height of the settled fibers was read and the bulk specific gravity in water was calculated using the following calculation formula (1).

[0023] Bulk density in water (g / cm 3 ) = 5.0 (g) / fiber sedimentation volume (cm 3 )…(1)

[0024] The papermaking mat of the present invention comprises fiber bundles.

[0025] This fiber bundle is formed by interweaving more than 10 of the above-mentioned inorganic fibers in a twisted manner, supporting each other, and therefore not easily deformed by pressure. Therefore, when pressure is applied to the paper-made mat, the fiber bundle acts as a core material, and can alleviate the pressure on the inorganic fibers that do not constitute the fiber bundle. Therefore, it is possible to prevent the inorganic fibers that do not constitute the fiber bundle from breaking due to pressure. As a result, the surface pressure of the paper-made mat of the present invention increases.

[0026] In addition, in the paper-made mat of the present invention, the average length of the fiber bundle exceeds 5 mm.

[0027] The papermaking mat of the present invention is produced by flowing a slurry containing inorganic fibers in a certain direction to pick up the inorganic fibers.

[0028] If the slurry contains fiber bundles having an average length exceeding 5 mm, the produced papermaking mat of the present invention also contains such fiber bundles.

[0029] When a slurry containing such a fiber bundle is made to flow in a certain direction, the fiber bundle is hooked on other inorganic fibers and is easily oriented in a direction perpendicular to the flow direction of the slurry.

[0030] Fiber bundles are stronger than inorganic fibers alone and are difficult to bend. Therefore, a papermaking mat in which the fiber bundles are oriented in one direction is difficult to bend in the direction in which the fiber bundles are oriented, but is easy to bend in a direction perpendicular to the direction in which the fiber bundles are oriented.

[0031] Therefore, even if such a paper-made mat is bent in a direction perpendicular to the direction in which the fiber bundles are oriented, stress is not likely to be generated. In addition, cracks caused by the stress are not likely to be generated.

[0032] Therefore, even when the paper-made mat of the present invention is wound around a substrate, cracks are unlikely to occur.

[0033] In addition, the paper-made mat of the present invention contains fiber bundles, and therefore, when the paper-made mat of the present invention is opened by the above-mentioned opening method, the fiber bundles are not opened but remain in their original state. In the slurry after opening, the density of inorganic fibers in the portion where the fiber bundles are formed is higher than that in the portion where the fiber bundles are not formed.

[0034] The bulk density of inorganic fibers in the pulp after fiber opening is 0.012 to 0.035 g / cm 3 This means that the ratio of the fiber bundles included in the paper-made mat is appropriate, and the effect of preventing the inorganic fibers that do not constitute the fiber bundles from being broken by pressure can be appropriately exhibited.

[0035] If the bulk density of inorganic fibers in the pulp after fiber opening is less than 0.012 g / cm 3 , the proportion of fiber bundles contained in the paper-made mat is reduced and the surface pressure of the paper-made mat is reduced.

[0036] If the bulk density of inorganic fibers in the pulp after fiber opening exceeds 0.035 g / cm 3 , the proportion of fiber bundles contained in the paper-made mat increases, and the softness of the paper-made mat decreases.

[0037] The paper-made mat of the present invention preferably contains 0.1 to 20 parts by weight of an organic binder and 0.1 to 10 parts by weight of an inorganic binder based on 100 parts by weight of the inorganic fibers.

[0038] The organic binder and the inorganic binder bond the inorganic fibers to each other and maintain the shape of the paper-made mat.

[0039] When the content of the organic binder and the inorganic binder is within the above range, the inorganic fibers are appropriately bonded to each other, and both the flexibility and the shape retention of the paper-made mat can be achieved.

[0040] In addition, it is possible to suppress the inorganic fibers from falling off and scattering from the papermaking mat.

[0041] In the papermaking mat of the present invention, the glass transition temperature Tg of the organic binder is preferably 5° C. or less.

[0042] When the glass transition temperature Tg of the organic binder is 5° C. or less, the strength of the organic binder film formed by the organic binder can be increased, and the film elongation can be high and the resulting papermaking mat can have excellent flexibility.

[0043] In the papermaking mat of the present invention, the organic binder is preferably at least one selected from the group consisting of acrylic resins, acrylate latexes, rubber latexes, carboxymethyl cellulose and polyvinyl alcohol functioning as water-soluble organic polymers, styrene resins functioning as thermoplastic resins, and epoxy resins functioning as thermosetting resins.

[0044] In the papermaking mat of the present invention, the inorganic binder preferably includes at least one of alumina, silica, silicon carbide, zirconium oxide, boron nitride, diamond and pumice.

[0045] These organic binders and inorganic binders are suitable for bonding the inorganic fibers to each other and maintaining the shape of the paper-made mat.

[0046] In the paper-made mat of the present invention, the fiber bundle is preferably formed by interweaving 10 or more inorganic fibers, the average length of the fiber bundle formed by interweaving 10 or more inorganic fibers is more than 5 mm and is 15 mm or less, and the average width of the fiber bundle is 0.2 to 1.0 mm.

[0047] If the fiber bundle is in this form, the fiber bundle has appropriate strength as a core material, and can alleviate the pressure on the inorganic fibers that do not constitute the fiber bundle. Therefore, the inorganic fibers that do not constitute the fiber bundle can be further prevented from breaking due to pressure, and the surface pressure of the papermaking mat of the present invention becomes higher.

[0048] In the paper-made mat of the present invention, the fiber bundle preferably includes a crimped fiber bundle, and the drawn length of the crimped fiber bundle measured by the following drawn length measuring method is preferably 0.1 mm or more longer than the length of the crimped fiber bundle.

[0049] Method for measuring drawing length:

[0050] The crimped fiber bundle is placed on a flat surface.

[0051] Observe the curled fiber bundle after standing still from above, trace along the curled fiber bundle from one end to the other end of the curled fiber bundle, and define the traced distance as the "tracing length of the curled fiber bundle."

[0052] When the drawn length of the crimped fiber bundle is longer than the length of the crimped fiber bundle by 0.1 mm or more, the elasticity of the crimped fiber bundle increases, and the surface pressure of the papermaking mat increases.

[0053] The method for producing a paper-made mat of the present invention is characterized in that it comprises: a fiber-opening step of opening an inorganic fiber molded body formed by gathering inorganic fibers in water to prepare a slurry, wherein the slurry contains fiber bundles formed by interweaving 10 or more of the inorganic fibers in a twisted manner and the inorganic fibers not constituting the fiber bundles; and a paper-making step of paper-making the slurry to prepare a paper-made mat, wherein in the fiber-opening step, the average length of the fiber bundles exceeds 5 mm, and the bulk specific gravity of the inorganic fibers contained in the slurry in water is 0.012 to 0.035 g / cm 3 The fiber is opened in this way.

[0054] In the method for producing a paper-made mat of the present invention, an inorganic fiber molded body is opened in water, and the obtained inorganic fibers are paper-made.

[0055] When the inorganic fiber molded body is opened, the inorganic fibers may not be completely opened, and a fiber bundle in which ten or more fibers are twisted and intertwined may be generated.

[0056] In the method for producing a paper mat of the present invention, such a fiber bundle is intentionally generated.

[0057] By generating only a predetermined amount of such fiber bundles, the bulk specific gravity of the inorganic fibers contained in the slurry in water can be set to 0.012 to 0.035 g / cm 3 .

[0058] The sheet mat produced by this method is unlikely to crack even after being wound around a substrate, and has a sufficiently high surface pressure.

[0059] In the method for producing a paper-made mat of the present invention, the inorganic fiber molded body preferably includes a first inorganic fiber molded body derived from a needle-punched mat and / or a second inorganic fiber molded body derived from a paper-made mat.

[0060] Regardless of whether the inorganic fiber molded body is derived from a needle punched mat or a paper-made mat, the first fiber bundle can be formed in the fiber opening step.

[0061] Effects of the Invention

[0062] According to the present invention, it is possible to provide a papermaking mat which is unlikely to crack even after being wound around a base material and has a sufficiently high surface pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1A This is a perspective view schematically showing an example of the papermaking mat of the present invention.

[0064] Figure 1B yes Figure 1A An enlarged view of the dotted line portion.

[0065] Figure 2 This is a schematic diagram of an example of a fiber bundle in a crimped state.

[0066] Figure 3 This is a cross-sectional view schematically showing an example of the exhaust gas purification device of the present invention.

[0067] The papermaking mat of the present invention will be described with reference to the drawings.

[0068] Figure 1A This is a perspective view schematically showing an example of the papermaking mat of the present invention.

[0069] Figure 1B yes Figure 1A An enlarged view of the dotted line portion.

[0070] like Figure 1A As shown, the paper-made mat 10 is a paper-made mat composed of inorganic fibers.

[0071] The copying mat 10 has a rectangular shape in a plan view, with a convex portion 11 a provided at one end portion 11 and a concave portion 12 a provided at the other end portion 12 .

[0072] As will be described in detail later, the papermaking mat 10 is wound around an exhaust gas treating body and is disposed in an exhaust gas purifying device.

[0073] The convex portion 11a and the concave portion 12a are shaped so as to fit in with each other when the papermaking mat 10 is wound around an exhaust gas treating body.

[0074] If such convex portions 11 a and concave portions 12 a are provided, the sealing property is improved when the papermaking mat 10 is disposed in an exhaust gas purifying device described later.

[0075] It should be noted that the papermaking mat of the present invention may not have convex portions and concave portions at the end portions.

[0076] like Figure 1B As shown, the paper mat 10 includes a fiber bundle 21 in which ten or more inorganic fibers 20 are twisted and intertwined, and inorganic fibers 22 that do not constitute the fiber bundle 21 .

[0077] The fiber bundle 21 may be in a straight state ( Figure 1B In the state indicated by symbol "21a", it can also be a curled state ( Figure 1B , the state represented by symbol "21b").

[0078] In this specification, the fiber bundle refers to a portion in a papermaking mat where inorganic fibers are concentrated and intertwined and have a higher density than other portions.

[0079] Here, the fiber bundle 21b in the crimped state will be described in detail below with reference to the drawings.

[0080] Figure 2 This is a schematic diagram of an example of a fiber bundle in a crimped state.

[0081] exist Figure 2 In the crimped fiber bundle 21b shown in FIG. 1 , it is preferable that the drawing length L of the crimped fiber bundle 21b measured by the following drawing length measuring method is t It is longer than the length L of the fiber bundle 21b in the crimped state, more preferably 0.1 mm or more longer, and further preferably 0.2 to 0.6 mm longer.

[0082] (Method for measuring drawing length)

[0083] The crimped fiber bundle 21b is placed still on a flat surface.

[0084] Next, the crimped fiber bundle 21b after being left to stand is observed from above, and a portion of the crimped fiber bundle 21b is viewed from one end portion P of the crimped fiber bundle 21b. 1 Draw to the other end P 2 , the drawn distance L t As "the drawing length of the fiber bundle in the crimped state".

[0085] When the drawing length L of the fiber bundle 21b in the crimped state t When it is longer than the length L of the crimped fiber bundle 21b, the elasticity of the crimped fiber bundle 21b becomes higher, and the surface pressure of the papermaking mat 10 increases.

[0086] The papermaking mat 10 preferably includes the following crimped fiber bundles 21b: Figure 2 In the crimped fiber bundle 21b shown in FIG. 1 , when measuring the “drawing length of the crimped fiber bundle”, the connection end P can be 1 and end P 2 The line segment S crosses the fiber bundle 21b in a crimped state two or more times.

[0087] The degree of crimping of the fiber bundle 21b in such a crimped state is appropriate, the elasticity of the fiber bundle 21b in the crimped state is increased, and the surface pressure of the papermaking mat 10 is increased.

[0088] In the papermaking mat 10, it is preferable that the drawing length L of the crimped fiber bundle 21b is t The ratio of the length L of the fiber bundle 21b in the crimped state is L t / L=1.1~1.6.

[0089] In the paper-made mat 10, the value of the following formula (1) is preferably 0.1 or more, and more preferably 0.2 to 0.6.

[0090] (L t -L) / Wb...(1)

[0091] It should be noted that "Wb" refers to the width of the fiber bundle 21b in a crimped state.

[0092] In the paper-made mat 10, the crimped fiber bundle 21b is placed on a flat surface, and the area of ​​the crimped fiber bundle 21b viewed from above is preferably 2.6 to 8.3 mm. 2 .

[0093] In the papermaking mat 10, the ratio of the number of crimped fiber bundles 21b contained in the fiber bundle 21 is preferably 85% or less, more preferably 60% or less, further preferably 30% or less, and further preferably 10 to 30%.

[0094] The fiber bundle 21 is formed by interweaving a plurality of inorganic fibers 20 and supporting each other, so it is not easy to be deformed by pressure. Therefore, when pressure is applied to the papermaking mat 10, the fiber bundle 21 acts as a core material and can alleviate the pressure on the inorganic fibers 22 that do not constitute the fiber bundle 21. Therefore, it is possible to prevent the inorganic fibers 22 that do not constitute the fiber bundle 21 from being broken by pressure. As a result, the surface pressure of the papermaking mat 10 increases.

[0095] The paper mat 10 includes the fiber bundles 21. Therefore, when the paper mat 10 is opened by the following opening method, the fiber bundles are not opened but remain in their original state. In the opened slurry, the density of inorganic fibers in the portion where the fiber bundles are formed is higher than that in the portion where the fiber bundles are not formed.

[0096] Fiber opening method for making mat:

[0097] The prepared mat was heat treated at 600°C for 1 hour.

[0098] Fibers in an amount of 5.0 g were unwound and weighed from the paper mat, and placed in a container filled with 400 cc of water.

[0099] After stirring for 10 minutes with a stirrer (product name: SMT-101, manufacturer: AS ONE) at a rotation speed of 1000 rpm, the mixture was transferred to a graduated cylinder container, and water was added so that the total volume became 500 cc.

[0100] After the mixture was left to stand for 30 minutes, the height of the settled fibers was read and the bulk specific gravity in water was calculated using the following calculation formula (1).

[0101] Bulk density in water (g / cm 3 ) = 5.0 (g) / fiber sedimentation volume (cm 3 )…(1)

[0102] When the paper-made mat 10 is opened by the above-mentioned paper-made mat opening method to obtain a slurry containing inorganic fibers, the bulk specific gravity in water of the inorganic fibers contained in the slurry is 0.012 to 0.035 g / cm 3 It should be noted that the bulk specific gravity in water of the inorganic fibers contained in the slurry is more preferably 0.014 to 0.028 g / cm 3 .

[0103] The bulk density of inorganic fibers in the pulp after fiber opening is 0.012 to 0.035 g / cm 3 This means that the ratio of the fiber bundles 21 included in the papermaking mat 10 is appropriate, and the effect of preventing the inorganic fibers 22 that do not constitute the fiber bundles 21 from being broken by pressure can be appropriately exhibited.

[0104] If the bulk density of inorganic fibers in the pulp after fiber opening is less than 0.012 g / cm 3 , the proportion of fiber bundles contained in the paper-made mat is reduced and the surface pressure of the paper-made mat is reduced.

[0105] If the bulk density of inorganic fibers in the pulp after fiber opening exceeds 0.035 g / cm 3 , the proportion of fiber bundles contained in the paper-made mat increases, and the softness of the paper-made mat decreases.

[0106] In the paper-made mat 10, the average length of the fiber bundle 21 formed by interweaving more than 10 inorganic fibers 20 is ( Figure 1BThe average length of the fiber bundle 21 is preferably greater than 5 mm and less than 15 mm, more preferably 7 to 13 mm.

[0107] Although described in detail later, the papermaking mat 10 is produced by flowing a slurry containing inorganic fibers in a certain direction to pick up the inorganic fibers.

[0108] If the slurry contains fiber bundles 21 in which 10 or more inorganic fibers are intertwined and the average length exceeds 5 mm, the manufactured paper mat 10 also contains such fiber bundles 21 .

[0109] When the slurry including the fiber bundles 21 is made to flow in a certain direction, the fiber bundles 21 are hooked on other inorganic fibers (20, 22) and are easily oriented in a direction perpendicular to the flow direction of the slurry.

[0110] The fiber bundles 21 are stronger and less likely to bend than the inorganic fibers 22 alone. Therefore, the papermaking mat 10 in which the fiber bundles 21 are oriented in one direction is less likely to bend in the direction in which the fiber bundles 21 are oriented, but is more likely to bend in a direction perpendicular to the direction in which the fiber bundles 21 are oriented.

[0111] Therefore, even if such a paper-made mat 10 is bent in a direction perpendicular to the orientation direction of the fiber bundles 21, stress is unlikely to be generated. In addition, cracks due to the stress are unlikely to be generated.

[0112] Therefore, even if the papermaking mat 10 is wound around a substrate, cracks are unlikely to occur.

[0113] On the other hand, if the average length of the fiber bundle is 5 mm or less, the fiber bundle is too short and it is difficult for the fiber bundle as a core material to alleviate the pressure on the inorganic fibers that do not constitute the fiber bundle.

[0114] If the average length of the fiber bundle exceeds 15 mm, the fiber bundle is too long and is easily bent when the side of the fiber bundle is pressed, making it difficult to function as a core material. In addition, when the paper-made mat is bent, the fiber bundle is easily broken, and if the fiber bundle is broken, cracks are easily generated in the paper-made mat starting from the broken portion.

[0115] In the paper-made mat 10, the average width of the fiber bundle 21 formed by interweaving more than 10 inorganic fibers 20 is ( Figure 1B The average value of the length represented by the symbol W is preferably 0.2 to 1.0 mm, more preferably 0.2 to 0.8 mm.

[0116] It should be noted that if Figure 1B As shown, when the fiber bundle 21 is in the straight state 21a and in the crimped state 21b, the maximum width ( Figure 1B, the lengths represented by symbols Wa and Wb respectively are the widths of the fiber bundle 21.

[0117] If the average width of the fiber bundle is less than 0.2 mm, the strength of the fiber bundle decreases, the fiber bundle is easily bent, and it is difficult for the fiber bundle to function as a core material.

[0118] When the average width of the fiber bundle exceeds 1.0 mm, the strength of the fiber bundle becomes too high, and the flexibility of the entire paper-made mat decreases.

[0119] The average length of a fiber bundle formed by entanglement of 10 or more inorganic fibers and the average width of a fiber bundle formed by entanglement of 10 or more inorganic fibers are values ​​measured as follows.

[0120] Cut 150cm from the paper mat 3 of the test piece.

[0121] Thereafter, the test piece was fired at 600° C. for 1 hour to thermally decompose the binder component.

[0122] Next, the test piece is placed in a container, and the container is vibrated up and down and left and right to disentangle the inorganic fibers constituting the test piece.

[0123] A fiber bundle in which 10 or more inorganic fibers are intertwined is taken out from the untied test piece, and the length and width of the fiber bundle are measured.

[0124] The same operation was repeated three times, and the average values ​​of the length and width of the obtained fiber bundle were calculated.

[0125] In addition, when calculating the average length and average width of the fiber bundle, the calculation was performed excluding the fiber bundle consisting of less than 10 inorganic fibers.

[0126] In the paper-made mat 10, the fiber bundles 21 are preferably oriented in one direction.

[0127] When the fiber bundles 21 are oriented in one direction, stress is unlikely to be generated even if the papermaking mat 10 is bent in a direction perpendicular to the oriented direction of the fiber bundles 21. In addition, cracks due to the stress are unlikely to be generated.

[0128] Therefore, even if the papermaking mat 10 is wound around a substrate, cracks are unlikely to occur.

[0129] Whether the fiber bundle 21 is oriented in one direction is determined by the following method.

[0130] First, if Figure 1B As shown, on the first main surface of the paper-made mat 10, from one end 21e of the fiber bundle 21 1 Lead out and connect the other end 21e 2Next, the acute angle a formed by the line segment and an arbitrary direction d is measured. When the angle is 0 to 45°, the fiber bundle 21 that is the source of the line segment is regarded as the fiber bundle 21 oriented in the direction d.

[0131] If 50% or more of the entire fiber bundles 21 in any range of 5 cm×5 cm in length and width on the first main surface of the paper mat 10 are fiber bundles 21 oriented in the direction d, the entire fiber bundles 21 are determined to be oriented in the direction d.

[0132] When the fiber bundle 21 is in such a state, it is determined that “the fiber bundle is oriented in one direction” in the paper-made mat.

[0133] It should be noted that, as described above, in the papermaking process when manufacturing the papermaking mat 10, if the slurry containing the fiber bundles 21 is made to flow in a certain direction, the fiber bundles 21 will be hooked on other inorganic fibers (20, 22) and easily oriented in a direction perpendicular to the flow direction of the slurry.

[0134] Such a phenomenon that the fiber bundles 21 are oriented in a direction perpendicular to the flow direction of the slurry occurs in the entire thickness direction of the paper-made mat 10. Therefore, when the fiber bundles 21 are oriented in one direction on the main surface of the paper-made mat 10, it can be judged that the fiber bundles 21 are also oriented in one direction in the entire paper-made mat 10.

[0135] The inorganic fibers 20 constituting the papermaking mat 10 preferably include at least one selected from the group consisting of alumina fibers, silica fibers, alumina-silica fibers, mullite fibers, glass fibers, and biosoluble fibers.

[0136] When the papermaking mat 10 is composed of these inorganic fibers, the heat resistance is sufficient.

[0137] The inorganic fibers 20 constituting the paper-made mat 10 preferably have an average fiber diameter of 3 to 50 μm and an average fiber length of 100 to 100,000 μm.

[0138] The bulk density of the sheet mat 10 is preferably 0.05 to 0.30 g / cm 3 .

[0139] If the bulk density of the sheet mat 10 is less than 0.05 g / cm 3 , the inorganic fibers are weakly entangled with each other, and the inorganic fibers are easily peeled off, so it is difficult to maintain the shape of the papermaking mat in a predetermined shape.

[0140] If the bulk density of the sheet mat 10 exceeds 0.30 g / cm 3 , the papermaking mat becomes hard, the windability is reduced, and the mat is prone to rupture.

[0141] The paper-made mat 10 preferably contains 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, of an organic binder based on 100 parts by weight of the inorganic fibers 20 .

[0142] The inorganic binder is preferably contained in an amount of 0.1 to 10 parts by weight, more preferably 0.5 to 3.0 parts by weight, based on 100 parts by weight of the inorganic fibers 20 .

[0143] The organic binder and the inorganic binder bond the inorganic fibers to each other and maintain the shape of the paper-made mat.

[0144] When the content of the organic binder and the inorganic binder is within the above range, the inorganic fibers are appropriately bonded to each other, and both the flexibility and the shape retention of the paper-made mat can be achieved.

[0145] In addition, it is possible to suppress the inorganic fibers from falling off and scattering from the papermaking mat.

[0146] In the papermaking mat 10, the glass transition temperature Tg of the organic binder is preferably 5°C or less, more preferably -35 to 5°C.

[0147] When the glass transition temperature Tg of the organic binder is 5° C. or less, the strength of the organic binder film formed by the organic binder can be increased, and the film elongation can be high and the resulting papermaking mat can have excellent flexibility.

[0148] In addition, the mat 10 is less likely to break when it is wound around an exhaust gas treatment body, etc. In addition, since the organic binder film does not become too hard, it can connect the inorganic fibers to each other when the inorganic fibers break, and can suppress the scattering of the inorganic fibers.

[0149] When the glass transition temperature Tg of the organic binder exceeds 5° C., the flexibility of the papermaking mat may decrease and the elongation at break may decrease.

[0150] In the papermaking mat of the present invention, the organic binder may be a water-soluble organic polymer, a thermoplastic resin, or a thermosetting resin.

[0151] Examples of water-soluble organic polymers include acrylic resins, acrylate latex, rubber latex, carboxymethyl cellulose, and polyvinyl alcohol. Examples of thermoplastic resins include styrene resins. Examples of epoxy resins that function as thermosetting resins include.

[0152] In the copy mat 10 , the inorganic binder preferably contains at least one of alumina, silica, silicon carbide, zirconium oxide, boron nitride, diamond, and pumice.

[0153] These organic binders and inorganic binders are suitable for bonding the inorganic fibers to each other and maintaining the shape of the paper-made mat.

[0154] Next, the method for producing the papermaking mat of the present invention will be described.

[0155] The method for producing a paper-made mat of the present invention comprises (1) a fiber-opening step and (2) a paper-making step.

[0156] It should be noted that in the following description, the case of using both the first inorganic fiber molded body from the needle-punched mat and the second inorganic fiber molded body from the paper-made mat as the inorganic fiber molded body is described, but in the method for manufacturing the paper-made mat of the present invention, any inorganic fiber molded body can be used.

[0157] Each step is described in detail below.

[0158] (1) Fiber opening process

[0159] In this step, the first inorganic fiber molded body derived from the needle punched mat and the second inorganic fiber molded body derived from the papermaking mat are opened in water to prepare a slurry containing the opened inorganic fibers.

[0160] In this step, the bulk specific gravity of the inorganic fibers contained in the slurry in water is 0.012 to 0.035 g / cm 3 way to open the fiber.

[0161] In addition, in this process, it is preferable not to perform dry fiber opening before or after fiber opening in water.

[0162] When the needle punched mat or paper-made mat is opened, the inorganic fibers may not be completely opened, and fiber bundles in which a plurality of fibers are intertwined may be generated.

[0163] The reason for generating such a fiber bundle will be described below.

[0164] When the needle punch mat is produced, the inorganic fibers are intertwined with each other by needles, so that the inorganic fibers are strongly intertwined with each other in this portion.

[0165] In addition, when making a paper-made mat, inorganic fibers are bonded to each other with an organic binder, so that inorganic fibers are difficult to separate from each other. When making a paper-made mat by a paper-making method, the aggregation of inorganic fibers is uneven, and a high-density inorganic fiber aggregation is formed.

[0166] When the first inorganic fiber molded body from the needle-punched mat and the second inorganic fiber molded body from the paper-made mat are opened, the portion where the inorganic fibers are intertwined with each other by needles in the needle-punched mat and the aggregated portion of the inorganic fibers with high density in the paper-made mat are not easy to open and remain as twisted fiber bundles.

[0167] In the method for producing a paper mat of the present invention, such a fiber bundle is intentionally generated.

[0168] That is, in the method for producing a paper-made mat of the present invention, fiber opening is performed so that fiber bundles are formed and the average length of the fiber bundles exceeds 5 mm.

[0169] By generating only a predetermined amount of such fiber bundles, the bulk specific gravity in water of the inorganic fibers contained in the slurry can be set to 0.012 to 0.035 g / cm 3 .

[0170] In addition, the bulk specific gravity in water of the inorganic fibers contained in the slurry can be measured by the following method.

[0171] First, the slurry was completely dried, and 5.0 g of fibers were unwound and weighed from the dried slurry, and the fibers were placed in a container filled with 400 cc of water.

[0172] Next, the mixture was stirred at 1000 rpm for 10 minutes, transferred to a graduated cylinder, and water was added so that the total volume became 500 cc.

[0173] After the mixture was left to stand for 30 minutes, the height of the settled fibers was read and the bulk specific gravity in water was calculated using the following calculation formula (1).

[0174] Bulk density in water (g / cm 3 ) = 5.0 (g) / fiber sedimentation volume (cm 3 )…(1)

[0175] The fiber bundle contained in the slurry is preferably formed by entanglement of 10 or more inorganic fibers, and has an average length of 5 to 15 mm and an average width of 0.2 to 1.0 mm.

[0176] The fiber opening conditions are not particularly limited. For example, when fiber opening is performed in water using a stirrer, the bulk specific gravity of the inorganic fibers contained in the slurry in water can be adjusted to 0.012 to 0.035 g / cm by adjusting the rotation speed and time of the stirrer. 3 In addition, by adjusting the rotation speed and time of the mixer, the average length and average width of the fiber bundle can also be adjusted.

[0177] In addition, the fiber bundle generated in this step preferably originates from the needle traces of the first inorganic fiber molded body.

[0178] When the needle punch mat is manufactured, the inorganic fibers are intertwined by needle punching. When the needle punch mat is opened in water, inorganic fibers including a fiber bundle formed by intertwining a plurality of inorganic fibers are obtained. The fiber bundle is a crimped fiber bundle.

[0179] By adjusting the needle punching conditions, the bulk specific gravity in water of the inorganic fibers contained in the slurry can be easily adjusted to 0.012 to 0.035 g / cm 3 .

[0180] That is, the paper-made mat of the present invention can be easily produced by manufacturing the mat through a process of opening a predetermined needle punched mat.

[0181] As an example of fiber opening, the following method can be cited, for example.

[0182] First, the first inorganic fiber molded body and the second inorganic fiber molded body are fired at 500 to 1200°C for 0.5 to 10.0 hours. The preferred firing temperature is 800 to 950°C.

[0183] This makes it possible to thermally decompose the organic binder contained in the first inorganic fiber molded body and the second inorganic fiber molded body, and to easily open the first inorganic fiber molded body and the second inorganic fiber molded body.

[0184] Next, the fired first inorganic fiber molded body and the second inorganic fiber molded body are left to stand until they reach room temperature, and then the first inorganic fiber molded body and the second inorganic fiber molded body are untied by hand.

[0185] Next, the first inorganic fiber molded body and the second inorganic fiber molded body are added to water in an amount of 50 to 400 times by weight, and the mixture is stirred to open the fibers, thereby preparing a slurry containing inorganic fibers.

[0186] In addition, the stirring conditions are preferably set appropriately. For example, when making 10L of slurry, it is preferred to use (product name: SMT-101, manufacturer: AS ONE) as a stirrer, and stir at a rotation speed of 500 to 1000 rpm and a stirring time of 200 to 900 seconds. Preferably, the rotation speed is 650 to 850 rpm and the stirring time is 500 to 700 seconds, and more preferably the rotation speed is 700 to 800 rpm and the stirring time is 500 to 650 seconds.

[0187] As a result, the bulk specific gravity in water of the inorganic fibers contained in the slurry can be adjusted to 0.012 to 0.035 g / cm 3 , and the average length of the fiber bundles exceeds 5mm.

[0188] Next, an organic binder and an inorganic binder are added to the slurry.

[0189] The organic binder is preferably added in an amount of 0.1 to 20 parts by weight, more preferably 0.5 to 15.0 parts by weight, based on 100 parts by weight of the inorganic fibers in the produced papermaking mat.

[0190] The inorganic binder is preferably added in an amount of 0.1 to 15.0 parts by weight, more preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the inorganic fibers in the produced papermaking mat.

[0191] The types of preferred organic binders and inorganic binders have already been described, and thus their description is omitted here.

[0192] (2) Copying process

[0193] Next, the slurry is poured into a molding machine having a filter mesh formed on the bottom surface, and the solvent in the slurry is removed to obtain an inorganic fiber aggregate. The inorganic fiber aggregate is then dehydrated and dried.

[0194] It should be noted that in the papermaking process, the inorganic fiber aggregate may be dried by heating and pressing. During heating and pressing, the inorganic fiber aggregate may be heat-treated by blowing hot air through it to dry it, or it may be kept wet without heat treatment.

[0195] In the case of heat treatment, in order to prevent the organic binder from deteriorating due to heat, the heating temperature and the hot air temperature are preferably 100 to 250°C. Within the range of 100 to 250°C, the degradation of the organic binder can be suppressed, and at the same time, moisture can be dispersed from the inorganic fiber aggregate. When the heating temperature and the hot air temperature are less than 100°C, the temperature is not transmitted to the central part of the inorganic fiber aggregate, and the drying time becomes longer. In addition, if it exceeds 250°C, the organic binder is deteriorated, and the restraint force between the fibers is reduced, so the thickness of the inorganic fiber aggregate becomes difficult to control.

[0196] Through the above steps, the papermaking mat of the present invention can be produced.

[0197] It should be noted that, in the papermaking process, since no new fiber bundles are generated, if the obtained papermaking mat is opened by the above-mentioned fiber opening method to obtain a slurry containing inorganic fibers, the bulk specific gravity of the inorganic fibers contained in the slurry in water is 0.012 to 0.035 g / cm 3 .

[0198] In the method for producing a paper-made mat of the present invention, it is preferred that batch paper-making or continuous paper-making be performed in the paper-making step.

[0199] The paper-made mat of the present invention can be easily obtained by batch paper-making or continuous paper-making.

[0200] It should be noted that one embodiment of the paper-made mat of the present invention is a paper-made mat produced through the following steps: a fiber-opening step, in which an inorganic fiber molded body formed by a collection of inorganic fibers is fiber-opened in water to produce a slurry, wherein the slurry contains fiber bundles formed by twisting and interweaving more than 10 of the inorganic fibers, and the inorganic fibers that do not constitute the fiber bundles; a paper-making step, in which the slurry is paper-made to produce a paper-made mat; wherein, in the fiber-opening step, the average length of the fiber bundles exceeds 5 mm and the bulk specific gravity in water of the inorganic fibers contained in the slurry is 0.012 to 0.035 g / cm 3 The fiber is opened in this way.

[0201] Next, a method of using the papermaking mat of the present invention will be described.

[0202] Figure 3 This is a cross-sectional view schematically showing an example of the exhaust gas purification device of the present invention.

[0203] like Figure 3 As shown, the exhaust gas purification device 100 includes a metal casing 30, an exhaust gas treatment body 40 accommodated in the metal casing 30, and a papermaking mat 10 disposed between the exhaust gas treatment body 40 and the metal casing 30. The papermaking mat 10 is the papermaking mat of the present invention.

[0204] The exhaust gas treatment body 40 is a columnar body having a plurality of cells 41 arranged in parallel along the length direction with a cell wall 42 therebetween. It should be noted that an inlet pipe for introducing exhaust gas discharged from the internal combustion engine and an exhaust pipe for discharging exhaust gas passing through the exhaust gas purification device to the outside are connected to the end of the metal shell 30 as needed.

[0205] exist Figure 3 In the exhaust gas purification device 100 shown, an exhaust gas filter (honeycomb filter) in which any end of each groove is sealed with a sealing material 43 is used as the exhaust gas treatment body 40, but a catalyst carrier in which any end surface is not sealed with a sealing material may also be used.

[0206] like Figure 3 As shown, the exhaust gas ( Figure 3 In the figure, G represents exhaust gas and arrows represent the flow of exhaust gas) flows into a groove 41 opened at the exhaust gas inlet side end surface 40a of the exhaust gas treatment body (honeycomb filter) 40, and passes through the groove wall 42 separating the groove 41. At this time, PM in the exhaust gas is captured by the groove wall 42, and the exhaust gas is purified. The purified exhaust gas flows out from the other grooves 41 opened at the exhaust gas outlet side end surface 40b and is discharged to the outside.

[0207] As described above, the surface pressure of the papermaking mat 10 is high. Therefore, in the exhaust gas purifying device 100, even if the exhaust gas treating body 40 is subjected to high pressure from the exhaust gas, it is possible to prevent the exhaust gas treating body 40 from falling off from the metal casing 30.

[0208] The exhaust gas treatment body 40 may be made of non-oxidizing porous ceramics such as silicon carbide and silicon nitride, or may be made of oxidizing porous ceramics such as sialon, alumina, cordierite, and mullite. Among them, silicon carbide is preferred.

[0209] When the exhaust gas treating body 40 is a silicon carbide porous ceramic, the porosity of the porous ceramic is not particularly limited, but is preferably 35 to 60%.

[0210] If the porosity is less than 35%, the exhaust gas treatment body may be immediately clogged. On the other hand, if the porosity exceeds 60%, the strength of the exhaust gas treatment body decreases and the exhaust gas treatment body may be easily broken.

[0211] In addition, the average pore diameter of the porous ceramic is preferably 5 to 30 μm.

[0212] When the average pore size is less than 5 μm, PM may easily cause clogging.

[0213] If the average pore size exceeds 30 μm, PM may pass through the pores, making it impossible to capture PM and thus failing to function as a filter.

[0214] In addition, the said porosity and pore diameter can be measured by the conventionally well-known method, such as measurement using a scanning electron microscope (SEM).

[0215] The groove density in the cross section of the exhaust gas treatment body 40 is not particularly limited, but the preferred lower limit is 31.0 grooves / cm 2 (200 pcs / inch 2 ), the preferred upper limit is 93.0 pcs / cm 2 (600 pcs / inch 2 ). In addition, the more preferred lower limit is 38.8 pieces / cm 2 (250pcs / inch 2 ), and the more preferred upper limit is 77.5 pieces / cm 2 (500 pcs / inch 2 ).

[0216] The exhaust gas treatment body 40 may also be loaded with a catalyst for purifying the exhaust gas. As the loaded catalyst, a noble metal such as platinum, palladium, or rhodium is preferred, and platinum is more preferred. In addition, as other catalysts, alkali metals such as potassium and sodium, and alkaline earth metals such as barium may also be used. These catalysts may be used alone or in combination of two or more.

[0217] If these catalysts are loaded, PM can be easily burned and removed, and toxic exhaust gas can also be purified.

[0218] (Metal Housing)

[0219] The metal housing 30 is approximately cylindrical.

[0220] The inner diameter of the metal casing 30 (the inner diameter of the portion accommodating the exhaust gas treating body) is preferably slightly shorter than the diameter of the exhaust gas treating body 40 around which the papermaking mat 10 is wound.

[0221] The metal case 30 is not particularly limited, but is preferably made of stainless steel. Example

[0222] The following are examples that more specifically disclose the present invention, but it should be noted that the present invention is not limited to these examples.

[0223] (Example 1)

[0224] Prepare a first inorganic fiber molded body from a needle-punched mat, which is composed of Al 2 O 3 :SiO 2 =72:28 (weight ratio) of alumina-silica fiber, with a bulk density of 0.17g / mm 3 , the density of stitches is 21 / cm 2 density.

[0225] In addition, a second inorganic fiber molded body made of Al 2 O 3 :SiO 2 =72:28 (weight ratio) of alumina-silica fiber, with a bulk density of 1.2g / mm 3 .

[0226] Next, the first inorganic fiber molded body and the second inorganic fiber molded body were 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.

[0227] Next, the fired first inorganic fiber molded body and the second inorganic fiber molded body are left to stand until they reach room temperature, and then the first inorganic fiber molded body and the second inorganic fiber molded body are untied by hand.

[0228] Next, 5.0 g of the first inorganic fiber molded body and 5.0 g of the second inorganic fiber molded body were taken out and placed in 0.4 L of water. Then, a stirrer (product name: SMT-101, manufacturer: AS ONE) was used to stir and open the fibers at a rotation speed of 1000 rpm for 10 minutes to prepare an inorganic fiber slurry.

[0229] In order to confirm whether a fiber bundle was formed in the slurry, a part of the slurry was taken out and dried. As a result, it was confirmed that a fiber bundle in which 10 or more inorganic fibers were intertwined in a twisted manner was formed.

[0230] Next, an organic binder is added to the slurry in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of the inorganic fibers.

[0231] Furthermore, an inorganic binder is added to the slurry in an amount of 0.3 to 3.0 parts by weight based on 100 parts by weight of the inorganic fibers.

[0232] Next, the slurry was poured into a molding machine having a filter mesh formed on the bottom surface, and the solvent in the slurry was desolventized to obtain an inorganic fiber aggregate. Thereafter, the inorganic fiber aggregate was dehydrated and dried at 150 to 210° C. for 5 minutes to 1 hour to produce a paper-made mat of Example 1. The thickness of the paper-made mat of Example 1 was 13 mm.

[0233] (Comparative Example 1)

[0234] A mat made in Comparative Example 1 was produced in the same manner as in Example, except that the first inorganic fiber molded body and the second inorganic fiber molded body were fully untangled by hand without using a stirrer.

[0235] The thickness of the sheet mat of Comparative Example 1 was 12.9 mm.

[0236] (Determination of bulk density in water)

[0237] The sheet mats of Example 1 and Comparative Example 1 were heat treated at 600° C. for 1 hour.

[0238] Thereafter, the fibers were untied and weighed in an amount of 5.0 g, and the fibers were placed in a container filled with 400 cc of water.

[0239] After stirring at 1000 rpm for 10 minutes, the mixture was transferred to a graduated cylinder, and water was added to make the total volume 500 cc.

[0240] The mixture was left to stand for 30 minutes, the height of the settled fibers was read, and the bulk specific gravity in water was calculated using the following calculation formula (1).

[0241] Bulk density in water (g / cm 3 ) = 5.0 (g) / fiber sedimentation volume (cm 3 )…(1)

[0242] [Table 1]

[0243]

[0244] (Observation of fiber bundles)

[0245] 150 cm thick pieces were cut out from the sheet mats prepared in Example 1 and Comparative Example 1. 3 of the test piece.

[0246] Then, the test piece was fired at 600° C. for 1 hour to thermally decompose the binder component.

[0247] Next, the test piece is placed in a container, and the container is vibrated up and down and left and right to disentangle the inorganic fibers constituting the test piece.

[0248] A fiber bundle formed by entwining 10 or more inorganic fibers in a twisted manner was taken out from the untied test piece, and the length of the fiber bundle and the width of the inorganic fibers were measured.

[0249] The same operation was repeated three times, and the average values ​​of the fiber bundle length and the fiber bundle width were calculated.

[0250] The results are shown in Table 1.

[0251] (Measurement of surface pressure)

[0252] The sheet mats of Example 1 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 until the gap bulk density (GBD) was 0.40 mm. 3 / g. With a void bulk density (GBD) of 0.40mm 3 The / g state is maintained for 10 minutes.

[0253] Thereafter, the surface pressure of each paper-made mat was measured. The results are shown in Table 1.

[0254] (Evaluation of Winding Property)

[0255] The paper mats of Example 1 and Comparative Example 1 were cut into a rectangular shape having a length of 350 mm in the longitudinal direction and a length of 30 mm in the width direction to prepare test pieces.

[0256] In this case, in the papermaking process when producing the papermaking mat, the test piece was cut so that the direction in which the slurry flows into the former coincides with the longitudinal direction of the test piece.

[0257] Next, a cylinder with a diameter of 100 mm was prepared, and each test piece was wound around the cylinder in such a way that the length direction of each test piece was consistent with the winding direction. Then, each test piece was visually observed to see if cracks occurred. The evaluation criteria were as follows. The results are shown in Table 1.

[0258] ○: No cracks were observed.

[0259] ×: Cracks were observed.

[0260] As shown in Table 1, it is clear that the sheet-made mat of Example 1 has a high surface pressure and is less likely to crack even when wound around a substrate.

[0261] Explanation of symbols

[0262] 10 Copy pad

[0263] 11 One end

[0264] 11a convex part

[0265] 12 The other end

[0266] 12a recess

[0267] 20 Inorganic fiber

[0268] 21 Fiber bundle

[0269] 21a Fiber bundle in a straight state

[0270] 21b Fiber bundle in curled state

[0271] 22Inorganic fibers not forming fiber bundles

[0272] 30 Metal housing

[0273] 40 Exhaust gas treatment body

[0274] 40a Exhaust gas inflow side end

[0275] 40b Exhaust gas discharge side end

[0276] 41 slots

[0277] 42 groove wall

[0278] 43 Sealing material

[0279] 100 Exhaust gas purification device

Claims

1. A papermaking mat for an exhaust gas purification device composed of inorganic fibers, characterized in that: The paper-made mat includes a fiber bundle formed by entwining 10 or more of the inorganic fibers in a twisted manner and the inorganic fibers that do not constitute the fiber bundle. The average length of the fiber bundles exceeds 5 mm, When the paper-made mat is opened by the following paper-made mat opening method to obtain a slurry containing the inorganic fibers, the bulk specific gravity of the inorganic fibers contained in the slurry in water is 0.012 g / cm 3 ~0.035g / cm 3 , The fiber bundle includes a fiber bundle in a crimped state, and a drawn length of the fiber bundle in the crimped state measured by the following drawn length measuring method is longer than the length of the fiber bundle in the crimped state by 0.1 mm or more, The ratio of the number of the crimped fiber bundles contained in the fiber bundle is not less than 10% and not more than 85%, Fiber opening method for making mat: The prepared mat was heat treated at 600°C for 1 hour; Unwrap and weigh 5.0 g of fiber from the papermaking mat and place the fiber in a container filled with 400 cc of water; After stirring at 1000 rpm for 10 minutes, transfer to a graduated cylinder and add water until the total volume reaches 500 cc. After standing for 30 minutes, the height of the settled fibers was read and the bulk density in water was calculated using the following formula (1): Bulk density in water (g / cm 3 ) = 5.0 (g) / fiber sedimentation volume (cm 3 )･･･(1), Method for measuring drawing length: Place the curled fiber bundle on a flat surface. Observe the curled fiber bundle after standing still from above, trace along the curled fiber bundle from one end to the other end of the curled fiber bundle, and define the traced distance as "the traced length of the curled fiber bundle".

2. The copying mat according to claim 1, wherein: The organic binder is contained in an amount of 0.1 to 20 parts by weight and the inorganic binder is contained in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the inorganic fibers.

3. The copying mat according to claim 2, wherein: The Tg of the organic binder is 5° C. or less.

4. The copying mat according to claim 2 or 3, wherein: The organic binder is at least one selected from the group consisting of acrylic resin, acrylate latex, rubber latex, carboxymethyl cellulose and polyvinyl alcohol functioning as water-soluble organic polymers, styrene resin functioning as thermoplastic resins, and epoxy resin functioning as thermosetting resins.

5. The copying mat according to claim 2 or 3, wherein: The inorganic binder includes at least one of alumina, silicon dioxide, silicon carbide, zirconium oxide, boron nitride, diamond and pumice.

6. The copying mat according to claim 1 or 2, wherein: The fiber bundle is formed by interweaving more than 10 inorganic fibers. The average length of the fiber bundle formed by interweaving 10 or more inorganic fibers is more than 5 mm and less than 15 mm, The average width of the fiber bundle formed by interweaving 10 or more inorganic fibers is 0.2 mm to 1.0 mm.

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