Gasket and retaining seal

Abstract

The present invention provides a gasket having a laminated gasket in which an oriented layer composed of inorganic fibers and having the same orientation direction of the inorganic fibers and a random layer composed of inorganic fibers and having a random orientation direction of the inorganic fibers each contain at least one layer, and the laminated gasket contains a binder.

Description

TECHNICAL FIELD

[0001] The present application relates to a gasket and a retaining sealant. BACKGROUND

[0002] Particulate matter (hereinafter also referred to as PM) is contained in exhaust gas emitted from an internal combustion engine such as a diesel engine, and in recent years, the fact that this PM poses a problem for the environment and the human body has become an issue. In addition, since harmful gas components such as CO, HC, and NOx are also contained in the exhaust gas, there are concerns that these harmful gas components will have an impact on the environment and the human body.

[0003] Therefore, as an exhaust gas purification device that traps PM in exhaust gas or purifies harmful gas components, various exhaust gas purification devices have been proposed that are composed of an exhaust gas treatment body (which is composed of a porous ceramic such as silicon carbide or cordierite), a metal case that houses the exhaust gas treatment body, and a retaining sealant (gasket) that is disposed between the exhaust gas treatment body and the metal case. This retaining sealant (gasket) is provided with the main purpose of preventing damage from occurring in which the exhaust gas treatment body comes into contact with the metal case that covers the outer periphery thereof due to vibrations or impacts that occur as a result of the vehicle traveling, and preventing exhaust gas from leaking between the exhaust gas treatment body and the metal case.

[0004] As a gasket used in such a use, a retaining sealant is disclosed in Patent Literature 1, which is a retaining sealant composed of a gasket of a prescribed thickness that contains inorganic fibers whose surfaces are covered with an adhesive layer, characterized in that the adhesive layer contains an organic adhesive and an inorganic adhesive, and when the gasket is divided into a first surface portion, a central portion, and a second surface portion in the thickness direction, the amount of the organic adhesive added to the first surface portion is more than the amount of the organic adhesive added to the central portion, and more than the amount of the organic adhesive added to the second surface portion.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Publication No. 2015-63925 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] When winding is performed on the exhaust gas treatment body, sometimes winding work is performed while applying a tensile load to the gasket. In such work, if the tensile strength of the gasket is low, the gasket sometimes breaks due to the tensile load, which becomes a problem.

[0010] The tensile strength of the gasket described in Patent Literature 1 is also insufficient, and it is desirable to improve the tensile strength of the gasket.

[0011] The present application has been achieved in view of the above-described problems, and has an object to provide a gasket having high tensile strength.

[0012] Means for solving the problems

[0013] The gasket of the present application is provided with a laminated gasket in which an orientation layer composed of inorganic fibers and having the orientation direction of the inorganic fibers uniform, and a random layer composed of inorganic fibers and having the orientation direction of the inorganic fibers random, each contain at least one layer,

[0014] The laminated gasket contains a binder.

[0015] The laminated gasket constituting the gasket of the present application is provided with an orientation layer and a random layer. By the presence of the orientation layer, a gasket which is not easily elongated and has high tensile strength can be produced.

[0016] In addition, the binder is easily impregnated into the random layer. By containing the binder in the gasket, the frictional force of the surface of the gasket can be increased.

[0017] In the gasket of the present application, it is preferable that the orientation layer and the random layer be alternately laminated in the thickness direction, and that the random layer be provided on both the outermost layers of the laminated gasket.

[0018] When the binder is impregnated into the laminated gasket, the binder is provided on the outermost layer of the laminated gasket and penetrates in the thickness direction of the laminated gasket from the random layer. Since the binder is easily penetrated in the random layer and not easily penetrated in the orientation layer, the binder is blocked by the orientation layer in the thickness direction of the laminated gasket.

[0019] As a result, in the outermost layer of the laminated gasket, the content of the binder in the outermost layer contacted by the binder solution for impregnation of the binder is increased. If the content of the binder is large, the frictional force is increased, and therefore, if the outermost layer having a large content of the binder is used as the face of the gasket which is required to have frictional force when wound and which is in contact with the exhaust gas treatment body, the shift of the exhaust gas treatment body from the gasket can be prevented, and the gasket can be preferably used.

[0020] In the gasket of the present application, it is preferable that the laminated gasket contain at least one binder of an organic binder and an inorganic binder.

[0021] In the gasket of the present application, it is preferable that, when the laminated gasket is divided into a first surface portion, a central portion, and a second surface portion in the thickness direction, the random layer be provided on the outermost layer of the first surface portion,

[0022] The content of the binder in the first surface portion is larger than the content of the binder in the central portion, and larger than the content of the binder in the second surface portion.

[0023] In the above gasket, since the first surface portion has a high content of the binder, if the first surface portion is used as a portion to be brought into contact with the exhaust gas treatment body, the gasket can be prevented from being displaced from the exhaust gas treatment body, and can be preferably used.

[0024] In addition, the gasket is used in an exhaust gas purification device, but since the exhaust gas purification device is used in a high-temperature environment, the binder (particularly, an organic binder) sometimes volatilizes. Therefore, for the gasket to be used in the exhaust gas purification device, it is required not to increase the content of the binder.

[0025] In the above gasket, the content of the binder is increased in the first surface portion, rather than in the entire gasket. Therefore, the related requirements for the content of the binder in the entire gasket can be satisfied.

[0026] In the gasket of the present application, it is preferable that the content of the above binder satisfies the following relationship.

[0027] 0.4 ≤ (central portion / first surface portion)

[0028] 0.2 ≤ (second surface portion / first surface portion)

[0029] (second surface portion / central portion) ≤ 0.5

[0030] In addition, it is preferable that the content of the above binder further satisfies the following relationship.

[0031] 0 < (second surface portion / central portion)

[0032] If the content of the binder in the first surface portion, the central portion, and the second surface portion satisfies the above relationship, when the first surface portion is brought into contact with the exhaust gas treatment body and is wound, the friction between the gasket and the exhaust gas treatment body is increased, and interface slip between the gasket and the exhaust gas treatment body is less likely to occur when the gasket is assembled into a housing.

[0033] In the gasket of the present application, it is preferable that the inorganic fibers of the above orientation layer contain 70% or more of inorganic fibers having an inclination angle of 60 to 90 degrees with respect to the width direction of the gasket.

[0034] In the gasket of the present application, it is preferable that the tensile strength at break determined by a tensile test is 200 kPa or more.

[0035] In addition, it is preferable that the elongation at break determined by the tensile test is 3.5 mm or less.

[0036] When the tensile strength at break and the elongation at break determined by the tensile test are in the above ranges, the breakage of the gasket during the winding work to the exhaust gas treatment body or the like can be more reliably prevented.

[0037] In addition, if the tensile strength at the time of breakage is high and the elongation at the time of breakage is small, the workability at the time of winding is less likely to be deviated.

[0038] The holding seal material of the present application is composed of the mat material of the present application, and is used for holding an exhaust gas treatment body in an exhaust gas purifying device.

[0039] The mat material of the present application is a mat material which is less likely to be elongated and has a high tensile strength, and thus is less likely to be broken at the time of winding to an exhaust gas treatment body, and is suitable for use as a holding seal material. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 is a perspective view schematically showing an example of a mat material.

[0041] Figure 2 is a cross-sectional view of the mat material shown in Figure 1

[0042] Figure 3 is a perspective view schematically showing an example of an orientation layer.

[0043] Figure 4 is an example of a microscope photograph including inorganic fibers.

[0044] Figure 5 is a perspective view schematically showing an example of a random layer.

[0045] Figure 6 is a cross-sectional view of a needle-punched mat including a rivet portion.

[0046] Figure 7 is a cross-sectional view schematically showing an example of an exhaust gas purifying device.

[0047] Figure 8 is a perspective view schematically showing an example of an exhaust gas treatment body constituting an exhaust gas purifying device.

[0048] Figure 9 is a perspective view schematically showing an example of a manufacturing method of an exhaust gas purifying device. DETAILED DESCRIPTION

[0049] An example of a mat material and a holding seal material of the present application will be described in detail below using the drawings.

[0050] Figure 1 is a perspective view schematically showing an example of a mat material.

[0051] Figure 2 is a cross-sectional view of the mat material shown in Figure 1

[0052] Figure 1 ​​The shown mat 10 is a laminated mat 20 including an orientation layer 30 and a random layer 40.

[0053] The three layers of the random layer 40a, the orientation layer 30, and the random layer 40b are laminated in the thickness direction of the laminated mat 20 (direction indicated by double-headed arrow T). Figure 1 And Figure 2 The random layer 40a and the random layer 40b are layers of the same specification.

[0054] The laminated mat 20 is a mat whose length in the length direction (direction indicated by double-headed arrow L) is long. Figure 1

[0055] The laminated mat 20 has a first main face 23 and a second main face 24 as two main faces. The first main face 23 is a surface of the random layer 40a, and the second main face 24 is a surface of the random layer 40b.

[0056] The laminated mat 20 has four side faces, and the side faces in the length direction of the laminated mat 20 are a first long side face 25 and a second long side face 26. In addition, the side faces in the width direction of the laminated mat 20 (direction indicated by double-headed arrow W) are a first short side face 27 and a second short side face 28. Figure 1

[0057] The laminated mat 20 has a substantially rectangular shape in plan view, and a recess is formed in the first short side face 27 and a protrusion is formed in the second short side face 28. When the mat is wound around an exhaust gas purification device, an exhaust gas treatment body, or an exhaust pipe, which are cylindrical in outer shape, the recess and the protrusion become shapes that fit into each other.

[0058] Note that, in the mat of the present embodiment, the shapes of the portions that fit into each other are a recess and a protrusion, but the shapes of the portions that fit into each other can also be a combination of L-shaped shapes.

[0059] Figure 3 is a perspective view schematically showing an example of an orientation layer.

[0060] Figure 3 In the orientation layer 30, the inorganic fibers 31 that constitute the orientation layer 30 are schematically shown together with the orientation direction thereof. The orientation layer 30 is a layer that is composed of inorganic fibers and in which the orientation directions of the inorganic fibers are uniform.

[0061] In the orientation layer, it is preferable that the inorganic fibers be oriented in the same direction in the direction along the main face of the mat (LW plane direction) and in the length direction of the mat (L direction) or the width direction of the mat (W direction). Figure 3 Figure 3 Figure 3

[0062] Figure 3 ​​​​​In the orientation layer shown, the inorganic fibers are oriented in a direction along the length direction of the mat.

[0063] In the present specification, "the orientation direction of the inorganic fibers is uniform" means that the angle of the inorganic fibers is measured with respect to one direction of the photographed area (generally, the lateral direction of the photographed area) in a microscope photograph including the inorganic fibers, and that 50% or more of the fibers exist in the range of 75 to 90 degrees as a result.

[0064] Figure 4 is an example of a microscope photograph including inorganic fibers.

[0065] In the photograph shown, the inorganic fibers 31 are reflected. Figure 4 In the photograph shown, the inorganic fibers 31 are reflected. Figure 4 In the photograph shown, the inorganic fibers 31 are reflected.

[0066] That is, in the photograph shown, the inorganic fibers 31 are reflected. Figure 4 The layer of the photograph shown is an orientation layer.

[0067] In addition, the inorganic fibers of the orientation layer preferably include 70% or more of inorganic fibers having an inclination angle of 60 to 90 degrees with respect to the width direction of the mat.

[0068] If the orientation layer satisfies the above condition, the direction in which the tensile stress is applied at the time of winding the mat coincides with the orientation of the inorganic fibers, and thus the tensile strength of the mat is easily enhanced, and thus is preferred.

[0069] Figure 4 In the photograph shown, the lateral direction of the photograph is the width direction of the mat, and 78% of the inorganic fibers exist in the range of 60 to 90 degrees of the angle θ of the inorganic fibers.

[0070] That is, in the photograph shown, the inorganic fibers 31 are reflected. Figure 4 In the orientation layer of the photograph shown, the inorganic fibers include 70% or more of inorganic fibers having an inclination angle of 60 to 90 degrees with respect to the width direction of the mat.

[0071] The direction in which the inclination angle with respect to the width direction of the mat is 60 to 90 degrees can be said to be a direction along the length direction of the mat, and thus the inorganic fibers of the orientation layer can be said to be oriented in the length direction of the mat.

[0072] In the orientation layer, the proportion of the inorganic fibers in which the angle θ of the inorganic fibers measured with respect to the lateral direction (0° direction) of the photographed area is in the range of 75 to 90 degrees can be 60% or more, or 70% or more. In addition, the proportion of the inorganic fibers in which the angle θ is in the range of 75 to 90 degrees can be 90% or less, or 80% or less.

[0073] In the orientation layer, the inorganic fibers having an inclination of 60 to 90 degrees with respect to the width direction of the mat can include 75% or more, and can include 85% or more. In addition, the inorganic fibers having an inclination of 60 to 90 degrees with respect to the width direction of the mat can include 95% or less, and can include 90% or less.

[0074] Figure 5 is a perspective view schematically showing an example of a random layer.

[0075] Figure 5 In the middle, the random layer 40 is shown, and the inorganic fibers 41 constituting the random layer 40 are schematically shown.

[0076] The random layer 40 is a layer composed of inorganic fibers and in which the orientation direction of the inorganic fibers is random.

[0077] The "orientation direction of the inorganic fibers is random" in the present specification means that, in a microscope photograph including the inorganic fibers, the inorganic fibers can be visually confirmed not to be oriented in a specific direction in the photographed area. A layer in which the orientation of the inorganic fibers does not fall within the definition of the above-described orientation layer can be regarded as a random layer.

[0078] The orientation layer and the random layer in the laminated mat are preferably alternately arranged in the thickness direction. Figure 1 and Figure 2 In the middle, the random layer 40a / random layer 30 / random layer 40b are alternately arranged in this order, and the random layer is arranged in both the outermost layers of the laminated mat.

[0079] As for the number of laminated pieces of the mat in the laminated mat, there is no particular limitation as long as the orientation layer and the random layer each include at least one layer. Since it is preferable that the random layer be arranged in the outermost layer and the random layer and the orientation layer be alternately arranged, it is preferable that there be three pieces or five pieces. Examples that can be given are three layers of random layer / orientation layer / random layer, five layers of random layer / orientation layer / random layer / orientation layer / random layer, and the like.

[0080] The mat constituting the laminated mat includes inorganic fibers. The inorganic fibers are not particularly limited, and can be alumina fibers, silica fibers, or the like. In addition, they can be glass fibers, biodegradable fibers. As long as the properties required for the mat material such as heat resistance, wind erosion resistance, and the like are changed, it is preferable to use a thick diameter fiber or a fiber with a long fiber length that can adapt to the environmental regulations of each country.

[0081] Among these, inorganic fibers of low-crystalline alumina are preferable, and inorganic fibers of low-crystalline alumina composed of mullite are more preferable. Furthermore, inorganic fibers including spinel-type compounds are further preferable.

[0082] In the mat material of the present application, the laminated mat includes a binder.

[0083] By including a binder in the mat, the frictional force of the surface of the mat can be increased. Since the binder easily penetrates into the random layer, it is preferable to cause the binder to penetrate into the random layer.

[0084] The laminated mat preferably includes at least one of an organic binder and an inorganic binder.

[0085] By including a binder in the laminated mat, the frictional force of the mat can be increased.

[0086] As the organic binder, for example, a rubber-based resin, a styrene-based resin, a silicone-based resin, an acrylic-based resin, a polyester-based resin, a polyurethane resin, and the like can be given.

[0087] As the inorganic binder, an inorganic sol dispersion liquid (alumina sol, silica sol, zirconia sol, titanium dioxide sol, and the like) can be given.

[0088] The content of the binder included in the laminated mat (total amount of the organic binder and the inorganic binder) is preferably 0.2% by weight or more and 30% by weight or less with respect to the weight of the laminated mat. In addition, in the case of including the organic binder, the content of the organic binder is preferably 0.1% by weight or more and 20% by weight or less, and in the case of including the inorganic binder, the content of the inorganic binder is preferably 0.1% by weight or more and 10% by weight or less.

[0089] In the case where the laminated mat includes a binder, it is preferable that the outermost layer of the laminated mat be a random layer and that an oriented layer be disposed inside the random layer.

[0090] In the case where the binder is caused to penetrate into the laminated mat, the binder is disposed in the outermost layer of the laminated mat and penetrates in the thickness direction of the laminated mat from the random layer. Since the binder easily penetrates in the random layer and does not easily penetrate in the oriented layer, the binder is blocked by the oriented layer in the thickness direction of the laminated mat.

[0091] As a result, in the outermost layer of the laminated mat, the content of the binder in the outermost layer contacted by the binder liquid for penetration increases. If the content of the binder is large, the frictional force increases, and thus if the outermost layer having a large content of the binder is used as the face of the laminated mat that comes into contact with the exhaust gas processing body at the time of winding and requires a frictional force, the shift of the exhaust gas processing body from the mat can be prevented, and the laminated mat can be preferably used.

[0092] In addition, as a specific example of the configuration in which the outermost layer of the laminated mat is a random layer and an oriented layer is disposed inside the random layer, it is preferable that the oriented layer and the above-described random layer be alternately laminated in the thickness direction, and that random layers be disposed in both of the outermost layers of the laminated mat.

[0093] In addition, preferably, when the laminated mat is divided into a first surface portion, a central portion, and a second surface portion in the thickness direction, a random layer is disposed on the outermost layer of the first surface portion, the content of the binder in the first surface portion is more than that in the central portion, and more than that in the second surface portion.

[0094] Figure 2 In the laminated mat 20 shown in the cross-sectional view, the random layer 40a, the oriented layer 30, and the random layer 40b each have the same thickness, and thus the random layer 40a can be regarded as the first surface portion, the oriented layer 30 can be regarded as the central portion, and the random layer 40b can be regarded as the second surface portion. In this case, preferably, the content of the binder in the random layer 40a is more than that in the oriented layer 30, and more than that in the random layer 40b.

[0095] In the mat material in which the random layer is disposed on the outermost layer of the first surface portion, since the content of the binder in the first surface portion is more, when the first surface portion is used as a portion to be in contact with the exhaust gas treatment body, it is possible to prevent the exhaust gas treatment body from being deviated from the mat material, and the mat material can be preferably used.

[0096] In addition, the mat material is used in the exhaust gas purification device, but since the use environment of the exhaust gas purification device is a high-temperature environment, the binder (particularly, an organic binder) sometimes volatilizes. Therefore, for the mat material assumed to be used in the exhaust gas purification device, it is required not to increase the content of the binder.

[0097] In the mat material described above, the content of the binder is increased in the first surface portion, rather than being increased in the entire mat material. Therefore, it is possible to satisfy the related requirements for the content of the binder as the entire mat material.

[0098] In addition, the content of the binder preferably satisfies the following relationships.

[0099] 0.4 ≤ (central portion / first surface portion)

[0100] 0.2 ≤ (second surface portion / first surface portion)

[0101] (second surface portion / central portion) ≤ 0.5

[0102] In addition, the content of the binder preferably satisfies the following relationships.

[0103] 0 < (second surface portion / central portion)

[0104] If the content of the binder in the first surface portion, the central portion, and the second surface portion satisfies the above relationships, when the first surface portion is brought into contact with the exhaust gas treatment body and is wound, the frictional force between the mat material and the exhaust gas treatment body is increased, and when the mat material is assembled into the housing, the interface slip between the mat material and the exhaust gas treatment body is less likely to occur.

[0105] Further, the binder content of the first surface portion is preferably 0.1% by weight or more and 29.0% by weight or less, the binder content of the central portion is preferably 0.2% by weight or more and 15.0% by weight or less, and the binder content of the second surface portion is preferably 0.05% by weight or more and 5.0% by weight or less.

[0106] The tensile strength at break measured by the tensile test is preferably 200 kPa or more.

[0107] Further, the elongation at break measured by the tensile test is preferably 3.5 mm or less.

[0108] The tensile strength at break and the elongation at break are measured by cutting the mat into a sample having a length of 200 mm in the length direction of the mat and a width of 50 mm in the width direction of the mat.

[0109] The thickness of the sample is measured at three points, and a universal material testing machine having a chuck (gripping jig) for the tensile test is used to measure the load at break and the tensile distance when the mat is stretched at a speed of 100 mm / min in the length direction of the sample, with the chuck distance set to 40 mm on one side.

[0110] The calculation is performed by the following equation:

[0111] Tensile strength at break = Load at break / (Sample thickness x Width).

[0112] The tensile distance at break is taken as the elongation at break.

[0113] If the tensile strength at break and the elongation at break measured by the tensile test are within the above ranges, the breakage of the mat during the winding work on the exhaust gas treatment body or the like can be more reliably prevented.

[0114] Further, if the tensile strength at break is high and the elongation at break is small, the variation in workability during winding is reduced.

[0115] The oriented layer and the random layer constituting the laminated mat can be a papermaking mat obtained by a papermaking method or a needle punched mat obtained by a needle punching method.

[0116] In the case of the papermaking method, for example, an inorganic fiber such as alumina fiber, silica fiber, an inorganic binder, and water are mixed in a manner such that the content of the inorganic fiber in a raw material liquid becomes a predetermined value, and the mixture is stirred by a stirrer, thereby preparing a slurry containing the inorganic fiber. A colloidal solution composed of a high molecular compound or a resin can be contained in the slurry as needed. Next, the mixed liquid is caused to flow into a former having a filter screen formed on a bottom surface, and then the water in the mixed liquid is dewatered through the filter screen, thereby producing a raw material sheet. Subsequently, the raw material sheet is heated and compressed under predetermined conditions, thereby obtaining a papermaking mat.

[0117] In the case of the needle punching method, for example, a spinning mixture using an aqueous solution of basic aluminum chloride and silica sol as raw materials is spun by a wet spinning method, thereby producing an inorganic fiber precursor having an average fiber diameter of 3 to 10 μm. Next, the inorganic fiber precursor is compressed to produce a continuous sheet of a predetermined size, and a needle punching process is performed thereon, and then a firing process is performed, thereby obtaining a needle punching mat.

[0118] The method for producing the oriented layer and the random layer is not particularly limited, and for example, the following methods can be mentioned.

[0119] In the case where the oriented layer is produced by the papermaking method, a slurry containing inorganic fibers is caused to flow in one direction, and the orientation of the fibers in the flow direction is produced when the slurry is caused to flow in one direction, thereby forming the oriented layer.

[0120] In the case where the random layer is produced by the papermaking method, a slurry containing inorganic fibers is caused to flow into a mold from above the mold. Since the flow of the slurry does not occur, the fibers are not oriented in a particular direction, and the random layer is produced.

[0121] At least one of an organic binder and an inorganic binder can be contained in the slurry containing inorganic fibers.

[0122] In addition, the laminated mat can be a papermaking mat produced by performing a needle punching process on the oriented layer and the random layer which are laminated.

[0123] The laminated mat can be subjected to the application of a binder. In the case where the laminated mat is subjected to the application of a binder, a binder liquid containing a binder is caused to permeate in the thickness direction of the laminated mat from one main surface (which is assumed to be a first main surface) of the laminated mat.

[0124] The permeation of the binder liquid can be a method in which a binder solution is dropped on the mat by a curtain coating method or the like, thereby applying the binder solution to the inorganic fibers in the mat, or a method in which the binder solution is blown to the mat by spraying as in spray coating.

[0125] If the random layer is disposed at the outermost layer of the laminated mat and the oriented layer is disposed inside thereof, the binder in the random layer easily penetrates, and the binder in the oriented layer does not easily penetrate, so the binder is blocked by the oriented layer in the thickness direction of the laminated mat.

[0126] As a result, in the outermost layer of the laminated mat, the binder content in the outermost layer contacted by the binder solution for impregnation of the binder increases. If the binder content is high, the friction force increases, so if the outermost layer having a high binder content is used as the face of the exhaust treatment body that requires friction force at the time of winding, the shift of the exhaust treatment body from the mat material can be prevented, and the use can be preferably performed.

[0127] In addition, it is preferable that the needle punched mat contain the binder and have a rivet portion in which the binder concentration is higher than other portions in the thickness direction along the needle trace from the first main face of the laminated mat.

[0128] Figure 6 is a schematic cross-sectional view showing the needle punched mat including the rivet portion.

[0129] Figure 6 In the center, the rivet portion 51 generated by impregnation of the binder into the needle trace 50 (which is generated by the needle punching treatment from the first main face 23 of the laminated mat 20) is shown.

[0130] If the needle punched mat has the rivet portion, the penetration of the binder is performed in the thickness direction of the mat material, thereby generating the constraint between the inorganic fibers, and the structural reinforcement of the mat material is facilitated, so it is preferable.

[0131] The rivet portion is a portion in which the binder (organic binder) looks like a rivet when the binder is scorched at the cross section of the laminated mat by heating the mat material.

[0132] In addition, the depth of the rivet portion is not particularly limited.

[0133] In addition, Figure 6 In the center, the case in which the needle trace 50 exists in the second main face 24 of the laminated mat 20, but the binder does not penetrate from the second main face 24, so the rivet portion does not exist.

[0134] The mat material of the present application can be used as a holding seal material for holding an exhaust treatment body in an exhaust purification device.

[0135] The holding seal material of the present application is composed of the mat material of the present application and is used as a holding seal material for holding an exhaust treatment body in an exhaust purification device.

[0136] Figure 7 is a schematic cross-sectional view showing an example of the exhaust purification device.

[0137] As Figure 7As shown, the exhaust gas purification device 100 includes a metal housing 130, an exhaust gas treatment body 120 housed in the metal housing 130, and a gasket 10 disposed between the exhaust gas treatment body 120 and the metal housing 130 as a sealing material.

[0138] The exhaust gas treatment unit 120 is a columnar component with multiple cells 125 arranged side by side along its length through the cell walls 126. It should be noted that, at the end of the metal housing 130, an inlet pipe for introducing exhaust gas discharged from the internal combustion engine and an outlet pipe for discharging the exhaust gas that has passed through the exhaust gas purification device to the outside are connected as needed.

[0139] The following is for reference Figure 7 The case where the exhaust gas passes through the exhaust gas purification device 100 having the above-described configuration will be explained.

[0140] like Figure 7 As shown, the exhaust gas discharged from the internal combustion engine and flowing into the exhaust gas purification device 100 ( Figure 7 In the diagram, exhaust gas (G represents exhaust gas, and arrows indicate the direction of exhaust gas flow) flows into a channel 125 opening on the exhaust gas inflow side end face 120a of the exhaust gas treatment body (honeycomb filter) 120, and passes through the channel wall 126 that separates the channel 125. At this time, PM in the exhaust gas is captured by the channel wall 126, and the exhaust gas is purified. The purified exhaust gas flows out from other channels 125 opening on the exhaust gas outflow side end face 120b, and is discharged to the outside.

[0141] Figure 7 In the exhaust gas purification device 100 shown, the sealing material is the gasket 10 of the present invention. The first main surface 23 of the laminated gasket constituting the gasket 10 is disposed on one side of the exhaust gas treatment body 120, and the second main surface 24 is disposed on one side of the metal shell 130.

[0142] There are no particular restrictions on the material of the metal casing that makes up the exhaust gas purification device, as long as it is a heat-resistant metal. Specifically, stainless steel, aluminum, iron and other metals can be cited.

[0143] In addition to being roughly cylindrical, the shell shape can also be clam-shaped, roughly elliptical in cross-section, or roughly polygonal.

[0144] Figure 8 This is a perspective view schematically showing an example of an exhaust gas treatment unit constituting an exhaust gas purification device.

[0145] Figure 8The exhaust gas treatment body 120 shown is a cylindrical honeycomb structure made of ceramic, in which a plurality of cells 125 are arranged side by side in the length direction with cell walls 126 therebetween. Also, either end of the cells 125 is sealed with a sealing material 128. Also, a peripheral coating 127 is provided on the periphery of the honeycomb structure for the purpose of reinforcing the peripheral portion of the honeycomb structure, adjusting the shape, or improving the thermal insulation of the honeycomb structure.

[0146] In the case where either end of the cells 125 is sealed, when viewed from one end of the exhaust gas treatment body 120, it is preferable to alternately arrange cells whose ends are sealed and cells whose ends are not sealed.

[0147] The cross-sectional shape of the exhaust gas treatment body 120 obtained by cutting the exhaust gas treatment body 120 in a direction perpendicular to the length direction is not particularly limited, and can be a substantially circular shape, a substantially elliptical shape, a substantially triangular shape, a substantially quadrangular shape, a substantially pentagonal shape, a substantially hexagonal shape, or the like.

[0148] The cross-sectional shape of the cells 125 that make up the exhaust gas treatment body 120 can be a substantially triangular shape, a substantially quadrangular shape, a substantially pentagonal shape, a substantially hexagonal shape, or the like, or can be a substantially circular shape, a substantially elliptical shape. Also, the exhaust gas treatment body 120 can be a combination of cells having various cross-sectional shapes.

[0149] The material that makes up the exhaust gas treatment body 120 is not particularly limited, and non-oxides such as silicon carbide and silicon nitride, and oxides such as cordierite and aluminum titanate can be used. Among these, non-oxide porous sintered bodies such as silicon carbide and silicon nitride are particularly preferable.

[0150] These porous sintered bodies are brittle materials, and thus are easily damaged by mechanical impact or the like. However, if a gasket 10 (sealing material) is interposed around the periphery of the side surface of the exhaust gas treatment body 120, the impact will be absorbed, and thus it is possible to prevent cracks or the like from occurring in the exhaust gas treatment body 120 due to mechanical impact or thermal shock.

[0151] A catalyst for purifying exhaust gas can be supported in the exhaust gas treatment body, and as the supported catalyst, a noble metal such as platinum, palladium, rhodium, or the like is preferable, with platinum being more preferable. Also, as other catalysts, an alkali metal such as potassium or sodium, or an alkaline earth metal such as barium can be used. These catalysts can be used alone or in combination with two or more. If these catalysts are supported, PM is easily combusted and removed, and toxic exhaust gas can also be purified.

[0152] As the exhaust gas treatment body constituting the exhaust gas purification device, there can be a unitary honeycomb structure body which is integrally formed of cordierite or the like, or a collection honeycomb structure body in which a plurality of columnar honeycomb fired bodies which are formed of silicon carbide or the like and in which a plurality of through holes are arranged in parallel in the length direction with partition walls therebetween are bundled by a paste mainly containing ceramic.

[0153] In the exhaust gas treatment body constituting the exhaust gas purification device, the end portion of the cell can not be sealed by the sealing material. In this case, the exhaust gas treatment body functions as a catalyst carrier which purifies harmful gas components such as CO, HC, or NOx contained in the exhaust gas by loading a catalyst such as platinum.

[0154] The holding sealing material of the present application which is formed of the mat material of the present application is used by being wound around the exhaust gas treatment body. An example in which the wound body in which the holding sealing material is wound around the exhaust gas treatment body is arranged in the exhaust gas purification device is described.

[0155] Figure 9 is a perspective view schematically showing an example of a manufacturing method of the exhaust gas purification device.

[0156] As shown in Figure 9 , the holding sealing material which is formed of the mat material 10 is wound around the exhaust gas treatment body 120 along the periphery thereof to make a wound body 140. Next, the wound body 140 is housed in the metal case 130, whereby the exhaust gas purification device is manufactured.

[0157] In making the wound body 140, the first main face 23 of the laminated mat 20 constituting the mat material 10 is wound with the first main face 23 facing the exhaust gas treatment body 120. As a result, the first main face 23 becomes the face of the exhaust gas treatment body 120 side, and the second main face 24 becomes the face of the metal case 130 side.

[0158] Next, as a method of housing the wound body 140 in the metal case 130, for example, there can be mentioned a press-in method (staffing method) in which the exhaust gas treatment body 120 (wound body 140) in which the holding sealing material which is formed of the mat material 10 is arranged around the periphery is pressed into the inside of the metal case 130 to a prescribed position, a sizing method (swaging form) in which the inner diameter of the metal case 130 is reduced by compression from the outer peripheral side, a clamshell method in which the metal case is shaped so as to be separable into a first case and a second case, the wound body 140 is placed on the first case, and the second case is covered to seal, and the like.

[0159] In the case where the wound body is housed in the metal case by the press-in method (staffing method), the inner diameter of the metal case (inner diameter of the portion in which the exhaust gas treatment body is housed) is preferably slightly smaller than the outer diameter of the above-described wound body.

[0160] By these processes, the winding body in which the sealing material is wound on the exhaust gas treatment body can be disposed in the exhaust gas purification device.

[0161] The present specification discloses the following matters.

[0162] The present disclosure (1) is a mat material having a laminated mat in which an orientation layer composed of inorganic fibers and having the orientation direction of the inorganic fibers uniform and a random layer composed of inorganic fibers and having the orientation direction of the inorganic fibers random each include at least one layer, and the laminated mat includes a binder.

[0163] The present disclosure (2) is the mat material as described in the present disclosure (1), in which the orientation layer and the random layer are alternately laminated in the thickness direction, and the random layer is disposed in both the outermost layers of the laminated mat.

[0164] The present disclosure (3) is the mat material as described in the present disclosure (1) or (2), in which the laminated mat includes at least one binder of an organic binder and an inorganic binder.

[0165] The present disclosure (4) is the mat material as described in any one of the present disclosure (1) to (3), in which when the laminated mat is divided into a first surface portion, a central portion, and a second surface portion in the thickness direction, the random layer is disposed in the outermost layer of the first surface portion,

[0166] The content of the binder in the first surface portion is more than that in the central portion and more than that in the second surface portion.

[0167] The present disclosure (5) is the mat material as described in the present disclosure (4), in which the content of the binder satisfies the following relationship.

[0168] 0.4 ≤ (central portion / first surface portion)

[0169] 0.2 ≤ (second surface portion / first surface portion)

[0170] (second surface portion / central portion) ≤ 0.5

[0171] The present disclosure (6) is the mat material as described in the present disclosure (5), in which the content of the binder further satisfies the following relationship.

[0172] 0 < (second surface portion / central portion)

[0173] The present disclosure (7) is the mat material as described in any one of the present disclosure (1) to (6), in which the inorganic fibers of the orientation layer include 70% or more of inorganic fibers having an inclination angle of 60 to 90 degrees with respect to the width direction of the mat material.

[0174] The present disclosure (8) is the gasket described in any one of the present disclosure (1) to (7), in which the tensile strength at break determined by the tensile test is 200 kPa or more.

[0175] The present disclosure (9) is the gasket described in any one of the present disclosure (1) to (8), in which the elongation at break determined by the tensile test is 3.5 mm or less.

[0176] The present disclosure (10) is a holding seal material composed of the gasket described in any one of the present disclosure (1) to (9), for holding an exhaust gas treatment body in an exhaust gas purification device.

[0177] Example

[0178] (Example 1)

[0179] A papermaking mat composed of inorganic fibers, which becomes an oriented layer and a random layer, was produced by a papermaking method, and was laminated in the order of random layer / oriented layer / random layer / oriented layer / random layer, and was subjected to needle punching, to produce a laminated mat.

[0180] A binder liquid containing an organic binder was applied to one main surface (random layer) of the laminated mat, and was dried, to produce a gasket.

[0181] The laminated mat was divided into three in the thickness direction, and the portion containing the random layer on the side to which the binder liquid was applied was used as a first surface portion, and the portion containing the random layer on the side opposite to the side to which the binder liquid was applied was used as a second surface portion. The portion between the first surface portion and the second surface portion was used as a central portion.

[0182] The binder content was calculated from the change in weight before and after the application of the binder liquid.

[0183] The ratio of the binder contents, i.e., the binder content ratio, of two of the first surface portion, the central portion, and the second surface portion is shown in Table 1.

[0184] The photograph of the oriented layer is the photograph shown in Figure 4 The angle θ of the inorganic fibers was in the range of 75 to 90 degrees. In addition, the inorganic fibers having an inclination angle of 60 to 90 degrees with respect to the width direction of the gasket were present at 78%.

[0185] The random layer was photographed in the same manner as the photograph shown in Figure 4 The angle θ of the inorganic fibers was in the range of 75 to 90 degrees. In addition, the inorganic fibers having an inclination angle of 60 to 90 degrees with respect to the width direction of the gasket were present at 27%.

[0186] (Comparative Example 1)

[0187] A gasket (seal retaining material) of Example 1 of Patent Document 1 was prepared.

[0188] The gasket of Example 1 of Patent Document 1 was not a laminated gasket, and was not a gasket having both an oriented layer and a random layer inside thereof.

[0189] (Tensile Test)

[0190] A sample was prepared by cutting the gasket to have a length of 200 mm in the length direction of the gasket and a width of 50 mm in the width direction of the gasket.

[0191] The thickness of the sample was measured at three points, and using a universal material testing machine equipped with a chuck (gripping jig) for a tensile test, the chuck distance was set to 40 mm on one side, and the load at break and the tensile distance when the gasket was stretched at a speed of 100 mm / min in the length direction of the sample were calculated.

[0192] The calculation was performed by the following equation:

[0193] Tensile strength at break = Load at break / (sample thickness x width).

[0194] The tensile distance at break was taken as the elongation at break.

[0195] The results are shown in Table 1.

[0196] [Table 1]

[0197]

[0198] As is clear from the results shown in Table 1, the gasket of Example 1 had a high tensile strength.

[0199] Explanation of Symbols

[0200] 10 Gasket

[0201] 20 Laminated gasket

[0202] 23 First major surface of laminated gasket

[0203] 24 Second major surface of laminated gasket

[0204] 25 First long side surface of laminated gasket

[0205] 26 Second long side surface of laminated gasket

[0206] 27 First short side surface of laminated gasket

[0207] 28 Second short side surface of laminated gasket

[0208] 30 Oriented layer

[0209] 31 Inorganic fiber constituting oriented layer

[0210] 40, 40a, 40b random layer

[0211] 41 inorganic fiber constituting the random layer

[0212] 50 needle trace

[0213] 51 rivet portion

[0214] 100 tail gas purifying device

[0215] 120 tail gas processing body

[0216] 120a, 120b tail gas inflow side end surface

[0217] 125 channel

[0218] 126 channel wall

[0219] 127 outer peripheral coating layer

[0220] 128 sealing material

[0221] 130 metal shell

[0222] 140 winding body

Claims

1. A mat material, wherein the mat material has a layered mat in which an orientation layer composed of inorganic fibers and having the orientation direction of the inorganic fibers uniform and a random layer composed of inorganic fibers and having the orientation direction of the inorganic fibers random are each included in at least one layer, "the orientation direction of the inorganic fibers uniform" means that the angle of the inorganic fibers is measured in number with respect to one direction of a photographed area in a microscope photograph including the inorganic fibers, and 50% or more of the fibers exist in a range of 75 degrees to 90 degrees, the layered mat includes a binder, when the layered mat is divided into a first surface portion, a central portion, and a second surface portion in the thickness direction, the random layer is disposed in the outermost layer of the first surface portion, the content of the binder in the first surface portion is more than that in the central portion and more than that in the second surface portion.

2. The dunnage mat of claim 1, wherein, the orientation layer and the random layer are alternately layered in the thickness direction, and the random layer is disposed in both of the outermost layers of the layered mat.

3. The dunnage mat of claim 1 or 2, wherein, the binder is at least one of an organic binder and an inorganic binder.

4. The dunnage mat of claim 1 or 2, wherein, the content of the binder satisfies the following relationship, 0.4 ≤ (central portion / first surface portion) 0.2 ≤ (second surface portion / first surface portion) (second surface portion / central portion) ≤ 0.

5.

5. The dunnage mat of claim 4, wherein, the content of the binder further satisfies the following relationship, 0 < (second surface portion / central portion).

6. The dunnage mat of claim 1 or 2, wherein, the inorganic fibers of the orientation layer include 70% or more of inorganic fibers having an inclination angle of 60 degrees to 90 degrees with respect to the width direction of the mat material.

7. The dunnage mat of claims 1 or 2, wherein, the tensile strength at break determined by a tensile test is 200 kPa or more.

8. The dunnage mat of claim 7, wherein, the elongation at break determined by a tensile test is 3.5 mm or less.

9. A holding seal material composed of the mat material according to claim 1 or 2 for holding an exhaust gas treatment body in an exhaust gas purification device.

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