JP5112029B2 - Sheet material and manufacturing method thereof, exhaust gas treatment device and manufacturing method thereof, and silencer - Google Patents

Description

  The present invention relates to a sheet material that includes inorganic fibers and has first and second surfaces perpendicular to the thickness direction, a method for producing such a sheet material, a holding seal material for such a sheet material, and / or heat insulation. The present invention relates to an exhaust gas treatment device provided as a material, and a method for manufacturing the same. The present invention also relates to a silencer provided with such a sheet material as a sound absorbing material.

  The number of automobiles has increased dramatically since the beginning of this century, and along with this, the amount of exhaust gas discharged from the internal combustion engine of automobiles has been increasing rapidly. In particular, various substances contained in the exhaust gas of a diesel engine cause pollution, and are now having a serious impact on the global environment.

  Under such circumstances, various exhaust gas treatment apparatuses have been proposed and put into practical use. A general exhaust gas processing apparatus is provided with a casing made of, for example, metal in the middle of an exhaust pipe connected to an exhaust gas manifold of an engine, and a plurality of longitudinal directions defined by cell walls therein. It has a structure in which an exhaust gas processing body having a cell extending to is arranged. Examples of the exhaust gas processing body include a catalyst carrier and an exhaust gas filter such as a diesel particulate filter (DPF). For example, in the case of DPF, one end of each cell is sealed in a checkered pattern, and particulates (particulates) are trapped on the cell wall until the exhaust gas is exhausted from the exhaust gas treatment body through each cell. Then, the fine particles can be removed from the exhaust gas. The constituent material of the exhaust gas treating body is a metal, an alloy, ceramic, or the like. A cordierite honeycomb filter is known as a representative example of an exhaust gas treating body made of ceramic. Recently, from the viewpoint of heat resistance, mechanical strength, chemical stability, etc., porous silicon carbide sintered bodies have been used as materials for exhaust gas treatment bodies.

  Usually, a holding sealing material is installed between the exhaust gas processing body and the casing. The holding sealing material prevents damage due to contact between the exhaust gas processing body and the inner surface of the casing that may occur when the vehicle travels, etc., and further prevents the exhaust gas from leaking untreated through the gap between the casing and the exhaust gas processing body. Used to prevent. The holding sealing material plays a role of preventing the exhaust gas processing body from being displaced due to the exhaust gas exhaust pressure. Furthermore, the exhaust gas treating body needs to be kept at a high temperature in order to maintain the reactivity, and the holding sealing material is also required to have heat insulation performance. As a member that satisfies these requirements, there are sheet materials made of inorganic fibers such as alumina fibers, and various sheet materials that have been manufactured by methods such as the “needling method” and the “paper making method” have been used so far. It is used as a holding sealing material (for example, Patent Document 1).

The holding sealing material is wound around at least a part of the outer peripheral surface excluding the opening surface of the exhaust gas treatment body, for example, the gripping portions at both ends are fitted to each other, and further, the holding seal material is connected to the exhaust gas treatment body by taping or the like. Integrated and used as a unit. Thereafter, the integrated product is accommodated in a casing to constitute an exhaust gas processing device.
JP-A-60-88162

  However, as the temperature of the exhaust gas is increased, the holding sealing material is required to further improve the heat insulating property for the following reason. (I) prevention of a decrease in holding force of the holding sealing material due to an increase in the interval between the casing and the exhaust gas processing body caused by thermal expansion of the casing due to heat transferred from the exhaust gas processing body to the casing; (ii) ) Prevention of heat deterioration of accessories (instruments, etc.) connected to the outer surface of the casing, (iii) Regeneration processing (when the exhaust gas treatment body is DPF, which burns the captured particulates at a high temperature) , Efficiency of processing that enables reuse of used DPF).

  Therefore, in order to further improve the heat insulating property of the holding sealing material, it can be considered that the interval between the exhaust gas treating body and the casing is made wider than before and the holding sealing material is formed thick. However, when such a thick holding sealing material is wound around the exhaust gas treating body, a larger circumferential length difference (difference between the outer circumferential length and the inner circumferential length) is generated in the holding sealing material. Therefore, “macro wrinkles” 310 as shown in FIG. 1 are likely to occur on the inner peripheral surface of the holding sealing material (the surface on the side in contact with the exhaust gas processing body). When many such “macro wrinkles” 310 exist at the time of assembling the exhaust gas processing apparatus, the maximum diameter Φ of the exhaust gas processing body 20 around which the holding sealing material 24A (also referred to as the sheet material 30A) is wound is set to a desired value P ( When the thickness of the holding sealing material is t1 and the diameter of the exhaust gas processing body is t2, it becomes larger than P = 2 × t1 + t2). Therefore, the exhaust gas processing body around which the holding sealing material is wound is placed in the casing. The problem that it becomes difficult to install arises. Further, even if such an exhaust gas treating body can be mounted in the casing, in that state, the compressive stress is locally concentrated on the protruding portion 320 on the outer peripheral side of the holding sealing material generated by the “macro wrinkle” 310. And the problem that the inorganic fiber of this location breaks and the holding power of a holding sealing material falls may arise.

  The problem as described above is not limited to the exhaust gas processing apparatus having the catalyst carrier or the DPF. For example, a similar problem may occur in a silencer such as a muffler for a two-wheeled vehicle or a four-wheeled vehicle.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a sheet material that is less likely to cause “macro wrinkles” due to a difference in circumferential length even when the sheet material becomes thick. The present invention also provides a method for producing such a sheet material, an exhaust gas treatment apparatus in which such a sheet material is applied as a holding sealing material and / or a heat insulating material, and such It is an object of the present invention to provide a method for manufacturing an exhaust gas treatment device. Furthermore, an object of the present invention is to provide a silencer in which the sheet material as described above is applied as a sound absorbing material.

  In this invention, it is a sheet | seat material which has a 1st and 2nd surface which contains an inorganic fiber and is perpendicular | vertical with respect to the thickness direction, Comprising: The said 1st surface is a 1st sheet | seat part which has a 1st bulk density And the second surface is constituted by a second sheet portion having a second bulk density larger than the first bulk density.

  By using such a sheet material of the present invention as a holding sealing material of an exhaust gas processing apparatus, “macro wrinkles” generated on the inner peripheral surface of the holding sealing material due to a difference in circumferential length can be suppressed.

  The sheet material according to the present invention may be obtained by laminating the first sheet portion and the second sheet portion in the thickness direction.

The sheet material according to the present invention may have needle marks, and the needle mark density on the first surface may be smaller than the needle mark density on the second surface. In this case, the needle scar density on the first and second surfaces is in the range of 2.0 / cm ^{2 to} 20.0 / cm ² , and the needle scar density on the first surface is second. It is preferable to be in the range of 0.3 times to 0.8 times the needle mark density on the surface of.

  Alternatively, the sheet material according to the present invention may be a sheet material manufactured by a papermaking method.

  The sheet material according to the present invention is configured by laminating a first base sheet having the first bulk density and a second base sheet having the second bulk density in the thickness direction. An adhesive layer may be provided at the boundary between the first and second base sheets.

  The sheet material according to the present invention may further contain a binder.

  Moreover, in this invention, it is a manufacturing method of the sheet | seat material which has the 1st and 2nd surface perpendicular | vertical with respect to the thickness direction including an inorganic fiber, Comprising: The 1st base sheet which has a 1st bulk density is prepared. And a step of preparing a second base sheet having a second bulk density greater than the first bulk density, and a step of joining the first and second base sheets. A method for producing a sheet material is provided.

  Here, the step of joining the base sheets may include a step of joining the first and second base sheets with an adhesive or an adhesive tape.

  The first base sheet or the second base sheet may be prepared by a needling treatment method.

  Alternatively, the first base sheet or the second base sheet may be prepared by a papermaking method.

  The present invention also provides a method for producing a sheet material having first and second surfaces containing inorganic fibers and perpendicular to the thickness direction by a needling treatment method, wherein the first surface and the second surface are used. Providing a raw material sheet of inorganic fibers having a needle treatment of the raw material sheet from each side of the first surface and the second surface of the raw material sheet, Obtaining a raw material sheet smaller than the needle mark density on the second surface; and firing the raw material sheet to obtain a sheet material having a needle mark density on the first surface lower than the needle mark density on the second surface. And a step of obtaining the sheet material.

  Furthermore, in the present invention, there is provided a method for producing a sheet material containing inorganic fibers and having first and second surfaces perpendicular to the thickness direction, and the first raw material slurry containing inorganic fibers is injected into a molding machine. A step of dehydrating the first raw material slurry, and a step of injecting a second raw material slurry having a higher binder content than the first raw material slurry onto the dehydrated first raw material slurry. And a step of dehydrating the second raw material slurry. A method for producing a sheet material is provided.

  Here, the manufacturing method of the sheet material according to the present invention may further include a step of impregnating the binding material.

  Furthermore, in the present invention, there is provided an exhaust gas processing apparatus comprising an exhaust gas processing body and a holding sealing material wound around at least a part of the outer peripheral surface of the exhaust gas processing body, wherein the holding sealing material is Provided is an exhaust gas treatment device comprising a sheet material, wherein the holding sealing material is wound around the exhaust gas treatment body such that the first surface of the sheet material is outside. Is done.

  In the present invention, since the first sheet portion having a lower bulk density and stretchability is provided on the outer peripheral side of the holding sealing material, the inner peripheral side of the holding sealing material even if a thick holding sealing material is used. In addition, “macro wrinkles” due to the circumference difference are less likely to occur.

Further, in the present invention, an exhaust gas inlet pipe and an outlet pipe,
An exhaust gas treating body installed between the inlet pipe and the outlet pipe;
An exhaust gas treatment device comprising:
At least a part of the inlet pipe is provided with a heat insulating material,
An exhaust gas treatment device is provided in which the heat insulating material is composed of the above-described sheet material.

  Here, the exhaust gas treating body may be a catalyst carrier or an exhaust gas filter.

  Furthermore, the present invention provides a method for manufacturing an exhaust gas treatment device comprising an exhaust gas treatment body and a holding sealing material wound around at least a part of the outer peripheral surface of the exhaust gas treatment body, as described above. Providing the sheet material manufactured by the manufacturing method as the holding sealing material, and winding the holding sealing material around the exhaust gas treating body with the first surface of the sheet material facing outside And a method for manufacturing an exhaust gas treatment device.

  Here, the exhaust gas treating body may be a catalyst carrier or an exhaust gas filter.

  Furthermore, the method for manufacturing an exhaust gas processing apparatus according to the present invention may include a step of mounting the exhaust gas processing body around which the holding sealing material is wound in a casing by a press-fitting method.

Furthermore, in the present invention, a silencer comprising an inner pipe, an outer shell that covers the outer periphery of the inner pipe, and a sound absorbing material installed between the inner pipe and the outer shell,
The sound absorbing material is composed of a sheet material having the above-described characteristics,
The sheet material is provided between the inner pipe and the outer shell so that the first surface is the outer side, and a silencer is provided.

  In such a silencer, since the first sheet portion having a lower bulk density and elasticity is provided on the outer peripheral side of the sound absorbing material, the inner peripheral side of the sound absorbing material even if a thick sound absorbing material is used. In addition, “macro wrinkles” due to the circumference difference are less likely to occur.

  According to the present invention, it is possible to provide a sheet material that is less likely to cause “macro wrinkles” due to a difference in circumferential length even when the sheet material is thick, and a method for manufacturing the sheet material. Moreover, in this invention, the exhaust-gas processing apparatus which applied such a sheet | seat material as a holding sealing material and / or a heat insulating material, and the method of manufacturing such an exhaust-gas processing apparatus are provided. Furthermore, the present invention provides a silencer in which the sheet material as described above is applied as a sound absorbing material.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

  In FIG. 2, an example of the form of the sheet material by this invention is shown. However, the sheet material of the present invention is not limited to the shape of FIG. FIG. 3 shows an exploded configuration diagram of an exhaust gas processing apparatus using the sheet material according to the present invention as a holding sealing material.

  When the sheet material 30 according to the present invention is wound around the exhaust gas processing body 20 such as a catalyst carrier and used as the holding sealing material 24 of the exhaust gas processing apparatus, the winding direction of the sheet material 30 is shown in FIG. A pair of fitting convex portions 50 and a fitting concave portion 60 are provided on both end faces 70 and 71 perpendicular to the (X direction). When the sheet material 30 is wound around the exhaust gas processing body 20, as shown in FIG. 3, the fitting convex portion 50 and the fitting concave portion 60 are fitted, and the sheet material 30 becomes the exhaust gas processing body 20. Fixed to. Thereafter, the exhaust gas processing body 20 around which the sheet material 30 is wound is press-fitted into a cylindrical casing 12 made of metal or the like, for example, by a press-fitting method, and the exhaust gas processing device 10 is configured.

  The sheet material 30 according to the present invention is mainly composed of inorganic fibers, but may further include a binder as described later.

  Here, the sheet material 30 of the present invention has two main surfaces perpendicular to the thickness direction, the first main surface has the first bulk density, and the second main surface is the first. It has the 2nd bulk density larger than a bulk density, It is characterized by the above-mentioned. Further, such a sheet material is configured to have a first sheet portion having the first bulk density and a second sheet portion having the second bulk density along the thickness direction. May be.

  For example, in FIG. 2, the sheet material 30 of the present invention has first and second main surfaces 82 and 84 perpendicular to the thickness direction. The sheet material 30 of the present invention includes a first sheet portion 420 having a first bulk density and a second sheet portion 430 having a second bulk density larger than the first bulk density. The first sheet portion 420 having the first bulk density is configured to be on the first main surface 82 side of the sheet material. Note that such a sheet material 30 may be configured by, for example, preparing the first sheet portion 420 and the second sheet portion 430 separately and then laminating them. Or you may form the sheet material 30 by adjusting the bulk density of the 1st and 2nd main surface of a sheet material simultaneously or continuously in a series of processes at the time of manufacture of a sheet material.

  In addition, in this application, a bulk density means the weight of the sheet material per unit volume, and the bulk density of the main surface of a sheet material is measured as follows.

First, the sheet material is cut out to a size of 50 mm × 50 mm using a cutting machine or the like. Next, with a cutter knife or the like, from the first and second main surfaces of the sheet material, the sheet material is cut in a direction substantially perpendicular to the thickness direction at a depth position of about 20% of the thickness of the sheet material, Take a sample of each major surface. Next, the weight W (g) and thickness T (cm) of each sample cut out are measured. The thickness of each sample is measured in a state where a weight having a surface area of about 3.1 cm ² (diameter 20 mmφ) and a weight of 31 g is added to the center of the sample (10 g / cm ² ). From the measurement results obtained, the bulk density on each main surface is calculated by bulk density (g / cm ³ ) = sample weight W / (sample thickness T × 5 cm × 5 cm). Such measurement is performed three times at different locations on the sheet material, and the average value of the values obtained on the respective main surfaces is defined as the bulk density (g / cm ³ ) of each main surface of the sheet material.

  Next, characteristic effects obtained by the sheet material 30 according to the present invention configured as described above will be described with reference to FIGS. 1 and 4. FIG. 1 shows a longitudinal direction of an exhaust gas processing body 20 (hereinafter referred to as “coated exhaust gas processing body” 210A) around which the sheet material 30A is wound when the conventional sheet material 30A is wound around the exhaust gas processing body 20. A cross section of a plane perpendicular to the direction is schematically shown. FIG. 4 schematically shows a similar cross section of the exhaust gas treating body 20 (hereinafter referred to as “coated exhaust gas treating body” 210) around which the sheet material 30 according to the present invention is wound.

  As shown in FIG. 1, normally, when the sheet material 30A is wound around the exhaust gas processing body 20, the circumferential length difference L (= LO−LI) between the outer periphery (LO) and the inner periphery (LI) of the sheet material 30A. Therefore, a large number of “macro wrinkles” 310 are generated on the inner peripheral side of the sheet material 30A. In the present application, the term “macro wrinkle” refers to a wrinkle having a length (height) H exceeding 2 mm or a width D of 3 mm when the coated exhaust gas treatment body is viewed in a cross section perpendicular to the longitudinal direction. Means more wrinkles. Therefore, it should be noted that the term “macro wrinkle” does not include fine wrinkles having a height of 2 mm or less and a width of 3 mm or less. The influence of this circumferential length difference L becomes more prominent as the thickness of the sheet material 30A increases. In the case of a thick sheet material, when the sheet material is wound around the exhaust gas processing body 20, it is generated on the inner peripheral side. The height H or width D of the “macro wrinkles” 310 is increased and / or the number of “macro wrinkles” 310 is increased.

  When a large number of such “macro wrinkles” 310 are generated in the sheet material 30A, the maximum diameter Φ of the coated exhaust gas treatment body 210A is a desired value P (the thickness of the holding seal material is t1, and the diameter of the exhaust gas treatment body is t2. Then, since P = 2 × t1 + t2), the problem arises that it becomes difficult to install the coated exhaust gas treating body 210A in the casing 12. Even if the coated exhaust gas treating body 210A can be mounted in the casing, in that state, the compressive stress is locally concentrated on the protruding portion 320 on the outer peripheral side of the sheet material 30A caused by the “macro wrinkle” 310. The problem is that the inorganic fiber at this location breaks and the holding power of the sheet material 30A is reduced.

  On the other hand, the sheet material 30 according to the present invention has at least two types of sheet portions 420 and 430 along the thickness direction, and the bulk density of the first sheet portion 420 is the second sheet portion 430. It is smaller than the bulk density. Further, the sheet material 30 is wound around the exhaust gas processing body 20 so that the first main surface 82 is on the outer peripheral side. 1, 3, and 4, the boundary between the first sheet portion 420 and the second sheet portion 430 is indicated by a broken line for the sake of clarity. It should be noted that in the absence of an “adhesive layer”, the boundary is often not so clear.

  In general, a sheet material having a small bulk density has a greater stretchability in the winding direction (X direction in FIG. 2) than a sheet material having a large bulk density. Therefore, when the sheet material 30 is wound around the exhaust gas processing body 20 so that the first main surface 82 constituted by the sheet portion 420 having a smaller bulk density is on the outer peripheral side, the influence of the peripheral length difference The occurrence of “macro wrinkles” 310 can be suppressed. This is because at the time of winding the sheet material, the outer peripheral side of the sheet material that is stretchable in the direction (X direction) can be extended so as to reduce the influence of the peripheral length difference from the inner peripheral length. is there. In this case, actually, as shown in FIG. 4, fine wrinkles (micro wrinkles) 410 having a height H in the thickness direction of 2 mm or less or a width D of 3 mm or less are provided on the inner peripheral side of the sheet material 30. Although many are formed, the number of large “macro wrinkles” 310 having a height H in the thickness direction exceeding 2 mm or a width D exceeding 3 mm, as in the prior art, is remarkably suppressed or completely eliminated.

  As described above, in the sheet material 30 according to the present invention, when it is wound around the exhaust gas processing body 20, the occurrence of “macro wrinkles” on the inner peripheral side due to the difference in the circumferential length, and further, the local occurrence of the sheet material due to this It is possible to suppress an increase in thickness. Therefore, it becomes easy to mount the coated exhaust gas processing body in the casing. In addition, it is difficult for the compressive stress to be locally applied to the coated exhaust gas treating body after being mounted in the casing, and it is possible to suppress a decrease in the holding force of the sheet material.

In the present invention, the bulk density of the first and second sheet portions 420 and ^430, is preferably in the range of ^{0.08g / cm 3 ~0.25g / cm 3} . When the bulk density of the first and second sheet portions 420 and 430 is less than 0.08 g / cm ³ , the strength of the sheet material is somewhat lowered. In addition, when the bulk density of the first and second sheet portions 420 and 430 exceeds 0.25 g / cm ³ , the sheet material becomes too hard and the flexibility is remarkably lowered, and the winding property to the exhaust gas processing body is reduced. Decreases. Further, even if the sheet material can be wound around the exhaust gas processing body, the sheet material has a large restoring force (force to return to the state before winding), so the end of the sheet material It becomes difficult to fit each other or to fix the positions of the ends using a tape or the like.

  Further, the ratio of the thicknesses of the first sheet portion 420 and the second sheet portion 430 is not particularly limited, but is, for example, in the range of 1: 9 to 9: 1, and particularly 4: 6 to 6: A range of 4 is preferable. Moreover, it is preferable that the thickness of the whole sheet | seat material before winding is 5-20 mm.

Also, the bulk density and basis weight of the entire sheet member is not specifically limited, the bulk density, for the reasons mentioned above, for ^example, those of ^{0.08g / cm 3 ~0.25g / cm 3} , as the basis weight, for ^example, those of 500g / ^{m 2} ~3000g / m 2 may be used. The basis weight means the total weight of fibers contained per unit area of the sheet material, but when the binding material is included in the sheet material, the total weight of the binding material and fibers contained per unit area is calculated. Say.

Further, when the sheet material is manufactured by the “needling treatment method” as described later, the needle mark density ratio of the first sheet portion 420 to the second sheet portion 430 is 0.3 to 0.00. A range of 8 is preferable. Further, the needle trace density of the first and second sheet portions 420 and 430 both preferably in the range of 2.0 pieces ^/ cm 2 to 20.0 cells / cm ^2. This is because if the density of one of the needle marks of the first and second sheet portions 420 and 430 is less than 2.0 / cm ² , the strength may decrease. On the other hand, when the needle mark density exceeds 20.0 / cm ² , even if the needle mark density is further increased, the bulk density hardly changes, and the sheet material becomes hard and handling properties deteriorate.

In the present application, the “needle trace” is a maximum dimension of 3 mm ² or less generated on the main surface of the sheet material when a fiber entanglement means such as a needle is inserted and removed from the sheet material manufactured by the “needling treatment method”. The fiber entanglement trace. Here, the needle mark density on the first and second main surfaces of the sheet material was measured by the following method.

First, using a cutting machine or the like, the sheet material is cut out to a size of 50 mm × 50 mm, and a measurement sample is collected. After the measurement sample is impregnated with a latex resin (resin amount 5 to 10 wt%), the measurement sample is sufficiently dried. Next, the measurement sample is cut in a direction substantially perpendicular to the thickness direction at a depth position of 2 mm from one main surface of the measurement sample with a cutter knife or the like. The new surface of the measurement sample thus obtained is referred to as surface A. Next, the fibers blocking the needle marks are removed using tweezers, the number of needle processing marks appearing on the surface A is counted, and the number per unit area is calculated. Such measurement was performed a total of three times at different locations on the target main surface of the sheet material, and the average value obtained was defined as the needle mark density (pieces / cm ² ) on the target main surface. The needle scar density on the other main surface is determined by the same measurement.

  As described above, the sheet material 30 according to the present invention includes the exhaust gas processing body 20 such that the first main surface 82 side having the first bulk density is the outer peripheral side (that is, the casing 12 side). It is wound around the outer periphery, and is used with its ends fitted and taped. The exhaust gas processing body 20 around which the sheet material 30 is wound is then installed in the casing 12 by a press-fitting method, a clamshell method, a tightening method, a sizing method, or other mounting methods, and the exhaust gas processing device 10 Is configured.

  Hereinafter, each mounting method will be described with reference to the drawings. 5, FIG. 6, FIG. 7 and FIG. 8 respectively show an exhaust gas processing body 20 in which the sheet material 30 is wound by a press-fitting method, a clamshell method, a tightening method, and a sizing method (that is, a coated exhaust gas treatment). A method for mounting the body 210) in the casing is schematically shown.

  The press-fitting method is a method of configuring the exhaust gas processing apparatus 10 by mounting the coated exhaust gas processing body 210 at a predetermined position by pushing the coated exhaust gas processing body 210 from one of the opening surfaces of the casing 121. . In order to facilitate the insertion of the coated exhaust gas treating body 210 into the casing 121, the inner hole diameter is shaped so as to decrease from one to the other as shown in FIG. 5, and the minimum inner hole diameter is the inner diameter of the casing 121. In some cases, a press-fitting jig 230 adjusted so as to have substantially the same dimensions as the above is used. In this case, the coated exhaust gas treating body 210 is inserted from the wide inner hole diameter side of the press-fitting jig 230 and is mounted in the casing 121 through the minimum inner hole diameter side.

  The sheet material of the present invention is particularly significant when the coated exhaust gas processing body is mounted in the casing by the press-fitting method. Due to the effect of suppressing the macro wrinkles 310 (and the protruding portions 320) of the sheet material as described above, the maximum diameter of the coated exhaust gas processing body is not greatly deviated from a desired value, and the insertion of the coated exhaust gas processing body is prevented. This is because it becomes easy.

  Next, in the clamshell method, as shown in FIG. 6, the casing member is divided so that a pair of casings are completed when facing each other (for example, divided into two in the example of FIG. 6). (122A, 122B) is used. After the coated exhaust gas treating body 210 is installed in one of these casing members, the remaining casing members are combined, and these members are further welded together by, for example, flange portions 220 (220A, 220B) to form the casing 122. By configuring the above, it is possible to obtain the exhaust gas processing apparatus 10 in which the coated exhaust gas processing body 210 is mounted at a predetermined position.

  Further, as shown in FIG. 7, the winding method is to wind a metal plate 123 serving as a casing member around the coated exhaust gas treatment body 210, and then tighten the metal plate 123 using a wire rope or the like. In this method, the metal plate 123 is brought into contact with the periphery of the coated exhaust gas treatment body 210 with a predetermined surface pressure. Finally, one end portion of the metal plate 123 is welded to the other end portion or the surface of the lower metal plate 123, whereby the exhaust gas treatment device 10 in which the covered exhaust gas treatment body 210 is mounted inside the casing 123. Is obtained.

  Further, as shown in FIG. 8, the sizing method includes inserting the coated exhaust gas treating body 210 into the metal shell 124 having an inner diameter larger than the outer diameter, and then using a press or the like to move the metal shell 124 to the outer peripheral side. And uniformly compressing (sizing (JIS-z2500-2002)). By the sizing process, the inner diameter of the metal shell 124 is accurately adjusted to a desired dimension, and the coated exhaust gas processing body 210 can be installed at a predetermined position.

  Normally, a metal such as a heat-resistant alloy is used as the casing material in these mounting methods.

  FIG. 9 shows a configuration example of the exhaust gas treatment device 10 according to the present invention. The exhaust gas processing apparatus 10 is connected to an exhaust gas processing body 20 in which a holding sealing material 24 is wound around an outer peripheral surface, a casing 12 that houses the exhaust gas processing body, and an inlet side and an outlet side of the casing. The exhaust gas inlet pipe 2 and the outlet pipe 4 are provided. In the example of FIG. 9, the inlet pipe 2 and the outlet pipe 4 have a tapered shape so that the diameter is expanded at a position where the inlet pipe 2 and the outlet pipe 4 are connected to the casing 12. However, such a tapered shape is not always necessary. In addition, a heat insulating material 26 is installed in a part of the inlet pipe 2 (in the example of FIG. 9, a tapered portion), so that the heat inside the exhaust gas treatment device 10 is transferred to the outside through the inlet pipe 2. Transmission is suppressed.

  In the example of this figure, the exhaust gas processing body 20 is a catalyst carrier having an opening surface for exhaust gas inlets and outlets and a large number of cells (or through holes) in a direction parallel to the gas flow. The catalyst carrier is made of, for example, porous silicon carbide having a honeycomb structure. However, the exhaust gas treatment device 10 of the present invention is not limited to such a configuration. For example, the exhaust gas treating body 20 may be a DPF in which one end of each cell is sealed in a checkered pattern.

  Here, the holding sealing material 24 is composed of the mat material 30 according to the present invention, and is wound around the exhaust gas processing body 20 so that the first sheet portion 420 is located outside (that is, the casing 12 side). . In such an exhaust gas processing apparatus, due to the effect of the sheet material as described above, when the sheet material 30 is wound around the exhaust gas processing body 20, “macro wrinkles” are suppressed from being generated on the inner peripheral side. Therefore, it is possible to suppress a decrease in the holding force of the sheet material 30 due to the breakage of the inorganic fibers when the sheet material 30 (that is, the holding sealing material 24) is mounted in the casing 12.

  It will also be apparent to those skilled in the art that in addition or alternatively, the thermal insulation 26 may be comprised of the sheet material 30 according to the present invention.

  Next, another application example of the sheet material according to the present invention will be described. In FIG. 10, an example of the silencer provided with the sheet | seat material by this invention is shown roughly. This silencer is provided in the middle of an exhaust pipe of an engine of a two-wheeled vehicle or a four-wheeled vehicle, for example. The silencer 700 includes an inner pipe 720 (for example, made of metal such as stainless steel), an outer shell 760 (for example, made of metal such as stainless steel) that covers the outer side, and a sound absorbing material 740 that is installed between the two. Have. In a normal case, a large number of small holes are formed on the surface of the inner pipe 720. In such a silencer 700, when exhaust gas is circulated in the inner pipe 720, the noise component contained in the exhaust can be attenuated by the sound absorbing material 740.

  Here, the sheet material 30 according to the present invention can be used as the sound absorbing material 740. In this case, the silencer 700 can be manufactured by the following process. First, the sheet material is wound around and fixed to the surface of the inner pipe 720 so that the first main surface 82 of the sheet material 30 becomes the outside. Next, the silencer 700 is obtained by press-fitting the inner pipe 720 around which the sheet material 30 is wound into the outer shell 760. By using the sheet material 30 for the sound absorbing material 740, when the sheet material 30 is wound around the inner pipe 720, the occurrence of “macro wrinkles” on the inner peripheral side due to the circumferential length difference, and further, An increase in local thickness can be suppressed. Therefore, it becomes easy to mount the inner pipe 720 in the outer shell 760. Further, it is difficult for the compressive stress to be locally applied to the inner pipe 720 after being mounted in the outer shell 760, and it is possible to suppress a decrease in the holding force of the sheet material.

  As a typical method for manufacturing the sheet material 30 having two main surfaces having different bulk densities according to the present invention, there are two methods of “bonding method” and “collective manufacturing method”.

  FIG. 11 shows a flowchart of a method for producing the sheet material 30 of the present invention by the “bonding method”. In this method, two base sheets having different bulk densities are independently manufactured, and then the base sheets are laminated and joined to produce a sheet material having two types of sheet portions having different bulk densities.

  First, in step S100, a first base sheet having a first bulk density is produced. As shown below, the first base sheet is manufactured, for example, by a “needling process” or a “paper making method”. In the present application, it should be noted that the term “needling treatment method” includes any sheet material manufacturing method including a needle treatment step in which a fiber entanglement means such as a needle is inserted into and removed from the sheet material. . Further, in the present application, it should be noted that the “papermaking method” means a method for producing a sheet material including the steps of fiber opening, slurrying, molding, and compression drying.

  Next, in step S110, a second base sheet having a second bulk density is produced. Similarly to the first base sheet, the second base sheet is also manufactured by the “needling treatment method” or the “paper making method”. In addition, the manufacturing method of a 1st base sheet and a 2nd base sheet may be the same, or may differ. In other words, when the first base sheet is manufactured by the “needling method”, the second base sheet may be manufactured by either the “needling method” or the “paper making method”. The same applies to the case where the first base sheet is manufactured by the “papermaking method”.

  Next, in step S120, after laminating the first base sheet and the second base sheet having different bulk densities, the two are joined. As a method of joining both base sheets, there are a method of bonding via an “adhesive layer” such as a double-sided tape or an adhesive, or a method of sewing and joining the base sheets together. In the former method of bonding via the “adhesive layer”, both base sheets are directly bonded via the “adhesive layer”, and heat is applied to one main surface of each base sheet at a temperature of 140 ° C. or the like. There is a method in which a plastic film (for example, a PE film, a walliff or the like) is thermally bonded, and a double-sided tape or an adhesive is installed on the film to bond both base sheets. As the adhesive, an acrylic adhesive, an acrylate latex, or the like can be used. Although the thickness of a double-sided tape, an adhesive agent, and a thermoplastic film is not specifically limited, For example, they are 0.02 mm-0.20 mm.

  In the present application, the “adhesive layer” means a layer placed at the interface between the two base sheets in order to join two base sheets, such as a double-sided tape or an adhesive, as described above. When a thermoplastic film is interposed, this film is included. Therefore, in the case of the configuration in which the thermoplastic film is interposed as described above, the thickness of the “adhesive layer” is the thickness of the thermoplastic film × 2 + the thickness of the double-sided tape (or adhesive). The thickness of the “adhesive layer” is, for example, in the range of 0.02 mm to 0.6 mm.

  In the “bonding method”, the sheet material according to the present invention is manufactured through such steps.

  Next, FIG. 12 shows a flowchart of a method for producing the sheet material 30 of the present invention by the “batch production method”. In this method, unlike the above-described method in which the sheet material is prepared separately, the bulk density of the first and second main surfaces of the sheet material is usually adjusted simultaneously or continuously in a series of steps. By doing so, two main surfaces having different bulk densities are formed.

  First, in step S200, the first main surface of the sheet material is adjusted to the first bulk density.

  Next, in step S210, the second main surface opposite to the first main surface of the sheet material is adjusted to the second bulk density, and the sheet material according to the present invention is completed. This process may be performed simultaneously with the above-described step S200, or may be performed after step S200. In other words, on both main surfaces of the sheet material, a first main surface having a first bulk density and a second main surface having a second bulk density are installed simultaneously, or After adjusting one main surface of the sheet material to the first bulk density, the other main surface of the sheet material may be adjusted to the second bulk density.

  Normally, the raw material sheet that is the base of this sheet material is manufactured by either the “needling process” or the “papermaking process”. In this case, it is not necessary to prepare each base sheet independently, and since a single manufacturing apparatus can be used, the manufacturing process can be simplified.

  However, both the “needling method” and the “paper making method” can be used in the “batch production method”. For example, a sheet portion having a first bulk density is first manufactured by the “needling process method”, and a sheet portion having a second bulk density is manufactured from the base sheet by the “paper making method”. By doing so, the sheet material of the present invention having different bulk densities can be produced on the two main surfaces. However, it is clear that such a method cannot obtain the above-mentioned advantages, unlike the case where a single method of “needling method” or “paper making method” is used. .

  Hereinafter, an example of a method for producing the sheet material of the present invention by the “bonding method” and the “batch production method” will be specifically described. In the following description, a sheet material containing a mixture of alumina and silica as an inorganic fiber will be described as an example. However, the fiber material is not limited to this, and may be composed of only one of alumina and silica, for example. Alternatively, other inorganic fibers may be used.

(Lamination method 1)
As described above, in this method, it is first necessary to prepare at least two base sheets having different bulk densities. Each such base sheet is manufactured through the steps of precursor preparation, blowing treatment, needle treatment, firing, and impregnation of a binder using a “needling treatment method”.

(Precursor preparation process)
Silica sol is added to a basic aluminum chloride aqueous solution having an aluminum content of 70 g / l and Al / Cl = 1.8 (atomic ratio) so that the alumina-silica composition ratio is 60 to 97:40 to 3, for example. A fiber precursor is prepared. In particular, the alumina-silica composition ratio is more preferably 70 to 97:30 to 3. When the alumina composition ratio is 60% or less, the composition ratio of mullite produced from alumina and silica is low, so that the thermal conductivity of the completed base sheet tends to be high and the heat insulation tends to be low. On the other hand, if the alumina composition ratio exceeds 97%, the flexibility of the inorganic fibers is impaired.

(Blowing process)
Next, an organic polymer such as polyvinyl alcohol is added to the alumina fiber precursor. Thereafter, this liquid is concentrated to prepare a spinning solution. Further, this spinning solution is used for spinning by a blowing process.

  The blowing process is a method of performing spinning by using an air stream blown from an air nozzle and a spinning liquid stream extruded from a spinning liquid supply nozzle. The gas flow rate per slit from the air nozzle is usually 40 to 200 m / s. The diameter of the spinning nozzle is usually 0.1 to 0.5 mm, and the liquid amount per spinning solution supply nozzle is usually 1 to 120 ml / h, but preferably 3 to 50 ml / h. Under such conditions, the spinning solution extruded from the spinning solution supply nozzle is sufficiently stretched without being sprayed (misted) and hardly welded between the fibers. A uniform precursor with a narrow diameter distribution can be obtained.

  The average diameter of the alumina fibers is not particularly limited, but, for example, those having a diameter of 3 μm to 10 μm can be used.

  Here, the average diameter of the fibers was measured by the following method. First, the alumina fiber obtained by the above method is put in a cylinder and pulverized under pressure at 20.6 MPa. Next, this sample is placed on a sieve net, and the sample that has passed through the sieve is used as an electron microscope observation specimen. After depositing gold or the like on the surface of the specimen, an electron micrograph at a magnification of about 1500 times is taken. The diameter of at least 40 fibers is measured from the obtained photograph. This operation was repeated for 5 samples, and the average of the measured values was taken as the average fiber diameter.

(Needle processing step)
A raw material sheet is manufactured by laminating the precursors that have been spun. Further, needle processing is performed on the raw material sheet. Usually, a needling device is used for the needle treatment.

Usually, a needling device is comprised by the needle board which can be reciprocated in the stab direction (usually up-down direction), and a pair of support plate installed in the both main surface sides of the surface of a raw material sheet, and a back surface. A large number of needles for piercing the raw material sheet are attached to the needle board at a density of about 25 to 5000/100 cm ² , for example. Each support plate is provided with a number of through holes for needles. Therefore, when the raw material sheet is pressed from both sides by a pair of support plates, the needle board is inserted into and removed from the raw material sheet by moving the needle board closer to or away from the raw material sheet, and a large number of needle traces in which fibers are entangled. Is formed. Here, in the needling device, the raw material sheet is further conveyed in a constant direction (for example, a direction substantially parallel to the main surface of the raw material sheet) at a constant feed rate (for example, about 1 mm / second to 20 mm / second). A conveying means may be provided. In this case, since it is possible to perform the needle treatment with the raw material sheet moved at a constant speed, the operation of moving the raw material sheet is not required each time the needle board is pressed once.

  As another configuration, the needling device may include a set of two needle boards. Each needle board has a respective support plate. Two needle boards are disposed on the front and back surfaces of the raw material sheet, respectively, and the raw material sheet is fixed from both sides with each support plate. Here, the needle is arranged on one needle board so that the position of the needle group on the other needle board does not overlap during needle processing. In addition, in consideration of the needle arrangement of both needle boards, each support plate is provided with a number of through holes so that the needle does not contact the support plate during the needle processing from both sides of the raw material sheet. ing. Using such an apparatus, the raw material sheet may be sandwiched from both sides with two support plates, and needle processing may be performed from both sides of the raw material sheet with two needle boards (hereinafter, such needle processing is performed). Especially “double needle treatment”). By removing and inserting the needle in this way, the processing time is shortened.

(Baking process)
Next, the obtained raw material sheet is heated from room temperature and continuously fired at a maximum temperature of about 1250 ° C. for 0.5 to 2 hours to obtain a base sheet having a desired bulk density.

(Binder impregnation process)
If necessary, the base sheet may be impregnated with a binder so as to be impregnated with a binder such as an organic resin. Thereby, the bulkiness of a base sheet can be suppressed. Moreover, it becomes possible to further suppress the detachment of the fibers from the base sheet. However, it is not always necessary to carry out the binder impregnation treatment at this stage. For example, after the two base sheets are joined (after step S120 in FIG. 11), the binder impregnation treatment may be performed.

  In the impregnation / adhesion treatment, the amount of attachment of the binder is preferably in the range of 1.0 to 10.0% by weight. If the amount is less than 1.0% by weight, the effect of preventing the inorganic fibers from falling is lowered. Moreover, when it exceeds 10.0 weight%, the quantity of the organic component discharged | emitted at the time of use of an exhaust-gas processing apparatus will increase.

  As the binder, an organic binder such as an epoxy resin, an acrylic resin, a rubber resin, or a styrene resin can be used. For example, acrylic (ACM), acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR) resin, or the like can be used.

  The base sheet is impregnated with the binder by spray coating using an aqueous dispersion prepared with such a binder and water. In addition, by this process, the excess adhering solid content and water added to the base sheet are removed as follows.

  Excess solid content is removed by a suction method using a suction device such as a vacuum pump. Moreover, you may implement the removal of an excess water | moisture content by heating a base sheet at the temperature of 90-160 degreeC, and / or compressing with the pressure of 40 kPa-100 kPa.

  Through such a process, two base sheets having different bulk densities are manufactured. In general, the needle mark density of the sheet material is correlated with the bulk density, and the bulk density increases as the needle mark density of the sheet material increases. In the needling treatment method, the bulk density of the mat can be adjusted by changing the ascending / descending speed of the needle board having a certain needle installation density and the feeding speed of the mat.

  Next, after laminating two base sheets having different bulk densities, they are joined by the above-described method (double-sided tape, adhesive or stitching) to obtain the sheet material according to the present invention.

(Lamination method 2)
In another example of the bonding method, a “papermaking method” is used to manufacture each base sheet. In the “paper making method”, two base sheets having different bulk densities are manufactured through the steps of fiber opening, slurrying, molding, and compression drying.

(Fiber opening)
First, the opening process of inorganic fiber is performed. The opening process is carried out alone or in a two-stage process including a dry opening process and a wet opening process. In the dry-type opening process, an apparatus such as a feather mill is used to open the raw material fibers. On the other hand, in the wet opening process, the cotton-like dry opening fiber obtained by the above-described dry opening process is put into a wet opening apparatus and further opened. For the wet opening process, a wet opening apparatus such as a pulper is used. Opened raw fiber can be obtained through such fiber opening treatment.

(Slurry process)
Next, the material fiber is put into a stirrer so that the weight of the raw fiber is 1 to 2 wt% with respect to water, and stirred for 1 to 5 minutes, for example. Next, 4 wt% to 8 wt% of an organic binder is added to this liquid and stirred for 1 to 5 minutes. Moreover, 0.5 wt%-1.0 wt% of inorganic binder is added to this liquid, and it agitates for 1 to 5 minutes. Further, about 0.5 wt% of a flocculant is added to this liquid, and the mixture is stirred for about 2 minutes at maximum to prepare a raw material slurry.

  As the inorganic binder, for example, alumina sol and / or silica sol is used. Examples of the organic binder include rubber materials, water-soluble organic polymer compounds, thermoplastic resins, thermosetting resins, and the like, and examples of the flocculant include Pacoll 292 (Ciba Specialty Chemicals (Ciba Specialty Chemicals)). Chemicals)) and the like are used.

(Molding process)
Next, the obtained raw material slurry is added to a molding machine having a desired shape, a base sheet raw material is formed, and dehydration is further performed. Normally, a filtering mesh (for example, mesh size: 30 mesh) is provided at the bottom of the molding machine, and moisture in the raw slurry added to the molding machine passes through this filtering mesh. Discharged. Therefore, by using such a molding machine, the base sheet material can be molded and dehydrated simultaneously. If necessary, moisture may be forcibly sucked from the lower side of the molding machine through a mesh for filtration using a suction pump, a vacuum pump, or the like.

(Compression drying process)
Next, the obtained base sheet raw material is taken out from the molding machine, and compressed using a press machine or the like so that the thickness becomes 0.3 to 0.5 times. Then, the base sheet can be obtained by heating and drying for 5 minutes to 1 hour.

  In addition, you may perform the binder impregnation process like the "bonding method 1" further using the obtained base sheet. However, as described above, in the case of the “bonding method”, such a binding material impregnation process may be performed after joining the two base sheets.

  Through such steps, two base sheets having different bulk densities are obtained. In the “paper making method”, the bulk density of the base sheet can be changed by changing the compression ratio of the base sheet in the compression drying step.

  Next, after laminating two base sheets having different bulk densities, the sheet material according to the present invention can be obtained by bonding by the above-described method (double-sided tape, adhesive, or stitching).

(Batch production method 1)
In the “collective manufacturing method”, the “needling method” and the “paper making method” can be used. “Batch production method 1” describes a “batch production method” based on the “needling process method”.

  Also in this method, a sheet material is basically manufactured in the same process as in the above-described “bonding method 1”. In particular, it is preferable to use the above-mentioned “double needle treatment” step. However, in this batch production method 1, the needle board used in the needle processing step of inserting and removing needles into the raw material sheet is different from that of the above-mentioned “bonding method 1”. Specifically, the total length of the needles installed on at least one of the two needle boards on both main surface sides of the raw material sheet used in the “double needle treatment” is based on the thickness of the raw material sheet. (For example, half the length of the raw material sheet), when the needle board is brought into contact with the raw material sheet, the needle does not reach the other surface side of the raw material sheet. In addition, the installation density of the needles installed on both needle boards may be different or the same. However, when the total length of the needles installed on both needle boards is shorter than the thickness of the raw material sheet, it is necessary to change the installation density of the needles installed on both needle boards. Otherwise, as a result, the needle mark density becomes equal on both main surfaces of the raw material sheet.

  Using these two needle boards, by inserting and removing needles from both sides of the raw material sheet, parts with different needle mark density and even bulk density are formed at a time in the thickness direction of the raw material sheet. can do.

  The steps after the baking are the same as those in the above-described “bonding method 1”. However, as a matter of course, this method does not require a step of joining two base sheets. In the above description, a method of performing needle processing on both main surfaces simultaneously using “double needle processing” has been described. It will be apparent that the needle treatment from each main surface side may be performed in turn instead.

(Batch production method 2)
In this method, two main surfaces having different bulk densities are formed for one sheet material in a series of steps by using the “papermaking method”. That is, also in this method, the sheet material is basically manufactured in the same process as in the above-described “bonding method 2”. However, in this method, the process of adding the raw material slurry to a molding machine having a desired shape and forming the sheet raw material is different from that described above. Specifically, in this method, the first raw material slurry is added to the molding machine, dehydrated, and before the sheet raw material is taken out (that is, in a semi-dried state), the binder compared to the first raw material slurry. The second raw material slurry having a high content of is added onto the dehydrated sheet raw material (hereinafter referred to as “first sheet raw material”). Next, the water contained in the second raw material slurry is discharged from the lower side of the molding machine through the first sheet raw material and the mesh for filtration, and the second raw material slurry is dehydrated to obtain the second sheet. Prepare raw materials. As described above, if necessary at this time, water may be forcibly sucked from the lower side of the molding machine.

  Through such a process, a sheet material in which the second sheet material is directly laminated on the first sheet material can be obtained. In this method, the bulk density of the first and second sheet raw materials can be controlled by changing the amount of the binder contained in the first and second raw material slurries. Therefore, after that, the sheet material according to the present invention can be obtained through the above-described compression drying process.

  In the above-described four types of manufacturing methods, the present invention has been described by taking as an example the case where the sheet material has two types of bulk density along the thickness direction. However, the present invention is not limited to the described configuration, and it will be apparent that the sheet material may have three or more types of bulk density portions along the thickness direction. The structure of such a sheet material is such that three or more types of base sheets having different bulk densities are stacked in “bonding method 1” and “bonding method 2”, or in “collective manufacturing method 2” It can be easily manufactured by adding a third raw material slurry to the sheet raw material.

  The effects of the present invention will be described below with reference to examples.

  In order to verify the effect of the present invention, a sheet material according to the present invention was produced by the above-described “bonding method 1”, and a winding test was performed. The sheet material was manufactured according to the following procedure.

Example 1
Silica sol is added to a basic aluminum chloride aqueous solution having an aluminum content of 70 g / l and Al / Cl = 1.8 (atomic ratio) so that the composition of the alumina fiber is Al ₂ O ₃ : SiO ₂ = 72: 28. Blended to form an alumina fiber precursor. Next, an organic polymer such as polyvinyl alcohol was added to the precursor of the alumina fiber. Further, this solution was concentrated to obtain a spinning solution, and this spinning solution was used for spinning by a blowing method. Thereafter, the precursors of the alumina fibers were folded and laminated to produce an alumina fiber material sheet. Next, needle processing was performed on this raw material sheet. The needle treatment was performed from one side of the raw material sheet by disposing a needle board on which needles were installed at a density of 80/100 cm ² only on one main surface side of the raw material sheet. In addition, the full length of the needle is longer than the thickness of the raw material sheet, and the needle can sufficiently penetrate the raw material sheet by pressure contact from one side of the needle board.

  Then, the obtained raw material sheet was continuously fired at a maximum temperature of 1250 ° C. for 1 hour. Next, the obtained sheet material was impregnated with a binder. An acrylic latex emulsion was used as the binder, and the impregnation amount was 5 wt% with respect to the total weight.

As a result, a first base sheet having a needle mark density of about 4.0 pieces / cm ² , a bulk density of 0.09 g / cm ³ , a basis weight of 750 g / m ² , and a thickness of 8.30 mm is obtained. It was. Moreover, the average diameter of the alumina fiber was 7.2 μm, and the minimum diameter was 3.2 μm. In addition, the needle mark density of the base sheet was measured by the method described above, including the following examples and comparative examples.

A second base sheet having a different needle mark density was produced by the same method. Here, when manufacturing the second base sheet, in order to increase the needle mark density, a needle board having needles installed at a density of 80/100 cm ² is disposed on one side of the base sheet, Needle treatment was performed. The obtained second base sheet has a needle mark density of about 5.7 / cm ² , a bulk density of 0.10 g / cm ³ , a basis weight of 750 g / m ² , and a thickness of 7.48 mm. there were. Moreover, the average diameter of the alumina fiber was 7.2 μm, and the minimum diameter was 3.2 μm.

Next, the first base sheet and the second base sheet are bonded to a double-sided adhesive tape (thickness: 100 μm,
And a sheet material having a total basis weight of 1500 g / m ² and a thickness of 15.83 mm was manufactured. This is Example 1.

(Example 2)
In the same manner as in Example 1, first and second base sheets were produced. However, in this example, the needle density of the needle board used in the needle treatment of the first base sheet is 80/100 cm ² , so that the needle mark density after the completion of the first base sheet is 2 0.7 / cm ² . The first base sheet had a bulk density of 0.08 g / cm ³ , a basis weight of 750 g / m ² , and a thickness of 9.42 mm. Moreover, the average diameter of the alumina fiber was 7.2 μm, and the minimum diameter was 3.2 μm. The specification of the second base sheet is the same as that of Example 1 (however, the thickness is 7.47 mm). The 1st base sheet and the 2nd base sheet were bonded together via the above-mentioned double-sided adhesive tape, and the sheet material of total basis weight 1500g / m < ² > and thickness 16.94mm was obtained. This sheet material is referred to as Example 2.

(Example 3)
A first base sheet was produced in the same manner as in Example 1. However, in this embodiment, the needle density of the needle board used during the needle processing of the first base sheet is 80/100 cm ² , so that the needle mark density after the completion of the first base sheet is 2.3. Pieces / cm ² . The first base sheet had a bulk density of 0.08 g / cm ³ , a basis weight of 750 g / m ² , and a thickness of 9.41 mm. Moreover, the average diameter of the alumina fiber was 7.2 μm, and the minimum diameter was 3.2 μm. Furthermore, a second base sheet was produced by the same method as in Example 1. However, in this embodiment, the needle density of the needle board used at the time of needle processing of the second base sheet is 80/100 cm ² , so that the needle mark density after completion of the second base sheet is 7.7. Pieces / cm ² . The second base sheet had a bulk density of 0.11 g / cm ³ , a basis weight of 750 g / m ² , and a thickness of 6.80 mm. Moreover, the average diameter of the alumina fiber was 7.2 μm, and the minimum diameter was 3.2 μm.

The 1st base sheet and the 2nd base sheet were bonded together via the above-mentioned double-sided adhesive tape, and the sheet material of total basic weight 1500g / m < ² > and thickness 16.26mm was obtained. This sheet material is referred to as Example 3.

Example 4
A first base sheet was produced in the same manner as in Example 1. However, in this embodiment, the needle density of the needle board used during the needle processing of the first base sheet is
By setting it to 80 pieces / 100 cm ² , the needle mark density after the completion of the first base sheet was set to 6.7 pieces / cm ² . The first base sheet had a bulk density of 0.10 g / cm ³ , a basis weight of 750 g / m ² , and a thickness of 7.46 mm. Moreover, the average diameter of the alumina fiber was 7.2 μm, and the minimum diameter was 3.2 μm. Furthermore, a second base sheet was produced by the same method as in Example 1. However, in this embodiment, the needle board density used for the needle processing of the second base sheet is 80/100 cm ² , so that the needle mark density after the completion of the second base sheet is 13.0. Pieces / cm ² . The second base sheet had a bulk density of 0.13 g / cm ³ , a basis weight of 750 g / m ² , and a thickness of 5.80 mm. Moreover, the average diameter of the alumina fiber was 7.2 μm, and the minimum diameter was 3.2 μm.

The 1st base sheet and the 2nd base sheet were bonded together via the above-mentioned double-sided adhesive tape, and the sheet material of total basis weight 1500g / m < ² > and thickness 13.31mm was obtained. This sheet material is referred to as Example 4.

(Comparative Example 1)
A first base sheet was produced in the same manner as in Example 1. However, in this comparative example, the needle density of the needle board used during the needle processing of the first base sheet is
By setting it to 80 pieces / 100 cm ² , the needle mark density after the completion of the first base sheet was set to 5.0 pieces / cm ² . The first base sheet had a bulk density of 0.10 g / cm ³ , a basis weight of 750 g / m ² , and a thickness of 7.54 mm . Moreover, the average diameter of the alumina fiber was 7.2 μm, and the minimum diameter was 3.2 μm. Further, a second base sheet was produced by the same method as the first base sheet. The second base sheet had a bulk density of 0.10 g / cm ³ , a basis weight of 750 g / m ² , and a thickness of 7.52 mm. Moreover, the average diameter of the alumina fiber was 7.2 μm, and the minimum diameter was 3.2 μm.
The 1st base sheet and the 2nd base sheet were bonded together via the above-mentioned adhesive tape, and the sheet material of total basic weight 1500g / m < ² > and thickness 15.11mm was obtained. This sheet material is referred to as Comparative Example 1.

(Comparative Example 2)
A first base sheet was produced in the same manner as in Example 1. However, in this comparative example, the needle density of the needle board used during the needle processing of the first base sheet is
By setting it to 80 pieces / 100 cm ² , the needle mark density after the completion of the first base sheet was set to 5.7 pieces / cm ² . The first base sheet had a bulk density of 0.10 g / cm ³ , a basis weight of 750 g / m ² , and a thickness of 7.48 mm. Moreover, the average diameter of the alumina fiber was 7.2 μm, and the minimum diameter was 3.2 μm. Furthermore, a second base sheet was produced by the same method as in Example 1. However, in this embodiment, the needle density of the needle board used at the time of the needle treatment of the second base sheet is 80/100 cm ² , so that the needle mark density after the completion of the second base sheet is 2.7. Pieces / cm ² . The second base sheet had a bulk density of 0.08 g / cm ³ , a basis weight of 750 g / m ² , and a thickness of 9.41 mm. Moreover, the average diameter of the alumina fiber was 7.2 μm, and the minimum diameter was 3.2 μm.

The 1st base sheet and the 2nd base sheet were bonded together via the above-mentioned adhesive tape, and the sheet material of total basic weight 1500g / m < ² > and thickness 16.94mm was obtained. This sheet material is referred to as Comparative Example 2.

  Table 1 summarizes the needle mark density, bulk density, basis weight, and thickness of each of the first and second base sheets in Examples 1 to 5 and Comparative Examples 1 and 2. In this table, the thickness of each sheet material constituted by the first and second base sheets and the ratio of the needle mark density of the first base sheet to the second base sheet are also shown.

（巻付試験）
次に、前述の方法で製作した各シート材を用いて、巻付試験を行った。

(Winding test)
Next, a winding test was performed using each sheet material manufactured by the above-described method.

  In the winding test, each sheet material is shaped as shown in FIG. 2 (full length: 295 mm in the X direction (including the fitting convex portion 50), 90 mm in the Y direction, and the length of the fitting convex portion 50: 30 mm in the X direction, 30 mm in the Y direction, The distance from the both ends of the Y direction to the fitting convex portion 50: 30 mm each was cut out and used as a test sample. This test sample was wound around a cylinder (length: 120 mm) having an outer diameter of 80 mm, and the ends were fitted together and fixed with tape as described above. Using calipers, the width (D) and height (H) of the wrinkles generated on the inner peripheral side of the sheet material at this time were measured as follows, and the occurrence of “macro wrinkles” was evaluated. First, as wrinkles to be measured, five wrinkles are selected in order from the largest, and the width and height are measured for each wrinkle. Next, the measured values of the width and height of each wrinkle were averaged, and the obtained results were taken as the width (D) and height (H) of the wrinkles of each sheet material. Then, when the calculated wrinkle width (D) exceeds 3 mm and / or the wrinkle height (H) exceeds 2 mm, it is determined that there is “macro wrinkle”, and other than that The case was determined to have no “macro wrinkles”.

  In any of the sheet materials of Examples 1 to 5 and Comparative Examples 1 and 2, the test sample was wound around a cylinder such that the first base sheet side was the outer peripheral side during the test.

(Test results)
Table 1 summarizes the results of the winding test (wrinkle dimensions and macro wrinkle determination results) obtained for each sheet material. From this result, when the needle mark density of the first base sheet is in the range of 0.3 to 0.8 times the needle mark density of the second base sheet, that is, the sheet materials of Examples 1 to 5 In the winding test, it was found that “macro wrinkles” do not occur on the inner peripheral side of the sheet material. On the other hand, when the needle mark density of the first base sheet is 1.0 times and 2.1 times the needle mark density of the second base sheet, that is, in the sheet materials according to Comparative Examples 1 and 2, the sheet material "Macro wrinkle" occurred on the inner circumference side of the.

  Here, the sheet material according to Comparative Example 1 corresponds to a sheet material having a uniform needle mark density in the thickness direction as conventionally used (that is, the first base sheet with respect to the second base sheet). 1 needle mark density ratio of base sheet = 1). The sheet material according to Comparative Example 2 is a sheet material configured by reversing the arrangement of both base sheets of the sheet material according to Example 2.

  From the results of Comparative Examples 1 and 2, macrowrinkle is suppressed by winding the sheet material around the exhaust gas treatment body such that the main surface having a large bulk density is the outer peripheral side of the two main surfaces of the sheet material. It was confirmed that the effect of

  The sheet material of the present invention can be used as a holding sealing material for a vehicle exhaust gas treatment device, a sound absorbing material for a silencer, and the like.

It is the figure which showed typically the cross-sectional form in the surface perpendicular | vertical with respect to the longitudinal direction of an exhaust-gas treatment body when the conventional sheet material is wound around an exhaust-gas treatment body. It is an example of the shape of the sheet material by this invention. It is a conceptual diagram which shows the state when the sheet | seat material by this invention is assembled | attached in a casing with an exhaust-gas process body. It is the figure which showed typically the cross-sectional form in the surface perpendicular | vertical with respect to the longitudinal direction of an exhaust-gas treatment body when the sheet | seat material by this invention is wound around an exhaust-gas treatment body. It is the figure which showed typically the method of installing a covering waste gas processing body in a casing by a press injection system. It is the figure which showed typically the method of installing a covering waste gas processing body in a casing by a clamshell system. It is the figure which showed typically the method of installing a covering waste gas processing body in a casing by the winding method. It is the figure which showed typically the method of installing a covering waste gas processing body in a casing by a sizing system. It is a figure which shows one structural example of the exhaust-gas processing apparatus of this invention. It is a figure which shows one structural example of the silencer of this invention. It is a flowchart of the method of producing the sheet material by this invention by the "bonding system." It is a flowchart of the method of producing the sheet material by this invention by a "batch production system".

Explanation of symbols

2 Introduction pipe 4 Exhaust pipe 10 Exhaust gas treatment device 12 Casing 20 Exhaust gas treatment body 24 Holding sealing material 24A Conventional holding sealing material 26 Heat insulating material 30 Sheet material 30A Conventional sheet material 50 Fitting convex portion 60 Fitting concave portion 82 1 Main surface 84 Second main surface 121, 122, 123, 124 Casing 210 Coated exhaust gas treatment body 210A Conventional coated exhaust gas treatment body 230 Press fitting jig 310 Macro wrinkle 320 Protruding portion 410 Micro wrinkle 420 First sheet portion 430 First Sheet part 700 of 2 Silencer 720 Inner pipe 740 Sound absorbing material 760 Outer shell.

Claims (12)

A sheet material that includes inorganic fibers and has first and second surfaces perpendicular to the thickness direction,
The first surface is composed of a first sheet portion having a first bulk density, and the second surface is a second sheet portion having a second bulk density greater than the first bulk density. Consisting of
The sheet material has needle marks, the needle mark density on the first surface is smaller than the needle mark density on the second surface,
The needle scar density on the first and second surfaces is both in the range of 2.0 / cm ^{2 to} 20.0 / cm ² ,
The sheet material characterized in that the needle mark density on the first surface is in the range of 0.3 to 0.8 times the needle mark density on the second surface .   The sheet material according to claim 1, wherein the sheet material is obtained by laminating the first sheet portion and the second sheet portion in a thickness direction. The sheet material is configured by laminating the first base sheet having the first bulk density and the second base sheet having the second bulk density along the thickness direction,
Wherein the first and the boundary of the second base sheet, the sheet material according to claim 1 or 2, characterized in that an adhesive layer. The sheet material according to any one of claims 1 to 3 , further comprising a binder. A method for producing a sheet material having first and second surfaces containing inorganic fibers and perpendicular to the thickness direction by a needling treatment method,
Providing a raw sheet of inorganic fibers having a first surface and a second surface;
The raw material sheet is needle-treated from each side of the first surface and the second surface of the raw material sheet, and the raw material sheet has a needle mark density on the first surface smaller than the needle mark density on the second surface. And getting the steps
Firing the raw material sheet to obtain a sheet material having a needle mark density on the first surface smaller than a needle mark density on the second surface ,
The needle scar density on the first and second surfaces is in the range of 2.0 / cm ^{2 to} 20.0 / cm ² ,
The needle surface density of the first surface is in the range of 0.3 to 0.8 times the needle surface density of the second surface ;
A method for producing a sheet material, comprising: The method for manufacturing a sheet material according to claim 5 , further comprising a step of impregnating the binding material. An exhaust gas treatment device comprising an exhaust gas treatment body and a holding sealing material wound around at least a part of the outer peripheral surface of the exhaust gas treatment body,
The holding sealing material is composed of the sheet material according to any one of claims 1 to 4 ,
The exhaust gas processing apparatus, wherein the holding sealing material is wound around the exhaust gas processing body such that the first surface of the sheet material is outside. Exhaust gas inlet and outlet pipes,
An exhaust gas treating body installed between the inlet pipe and the outlet pipe;
An exhaust gas treatment device comprising:
At least a part of the inlet pipe is provided with a heat insulating material,
The exhaust gas processing apparatus, wherein the heat insulating material is composed of the sheet material according to any one of claims 1 to 4 . The exhaust gas processing apparatus according to claim 7 or 8 , wherein the exhaust gas processing body is a catalyst carrier or an exhaust gas filter. An exhaust gas treatment device comprising: an exhaust gas treatment body; and a holding sealing material wound around at least a part of the outer peripheral surface of the exhaust gas treatment body,
Providing a sheet material manufactured by the manufacturing method according to claim 5 or 6 as the holding sealing material;
Winding the holding sealing material around the exhaust gas treating body such that the first surface of the sheet material is on the outside;
A method for manufacturing an exhaust gas treatment apparatus, comprising: The manufacturing method according to claim 10 , wherein the exhaust gas treating body is a catalyst carrier or an exhaust gas filter. A muffler having an inner pipe, an outer shell covering the outer periphery of the inner pipe, and a sound absorbing material installed between the inner pipe and the outer shell,
The sound absorbing material is constituted by the sheet material according to any one of claims 1 to 4 ,
The silencer, wherein the sheet material is installed between the inner pipe and the outer shell such that the first surface is the outside.

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