WO2023238591A1

WO2023238591A1 - Mat material, exhaust gas purification apparatus, and method for manufacturing exhaust gas purification apparatus

Info

Publication number: WO2023238591A1
Application number: PCT/JP2023/017666
Authority: WO
Inventors: 眞太朗宮崎; 孝太朗樽谷
Original assignee: イビデン株式会社
Priority date: 2022-06-09
Filing date: 2023-05-11
Publication date: 2023-12-14

Abstract

A mat material that is substantially rectangular in plan view and includes inorganic fibers, the mat material characterized by having a first main surface and a second main surface that face away from each other in the thickness direction, a first end surface and a second end surface that face away from each other in the longitudinal direction serving as a wrapping direction, and a first side surface and a second side surface that face away from each other in the width direction orthogonal to both the thickness direction and the longitudinal direction, the mat material moreover being characterized in that: a projecting section that protrudes toward the second end surface during wrapping, and non-protruding sections that are disposed on both width-direction sides of the projecting section and do not protrude toward the second end surface, are formed on the first end surface; a recessed section that corresponds to the shape of the projecting section of the first end surface during wrapping, and non-sunken sections that are disposed on both width-direction sides of the recessed section and correspond to the shapes of the non-protruding sections of the first end surface, are formed on the second end surface; and the ratio (D/C) of the width-direction length (D) of the non-sunken sections to the longitudinal-direction length (C) of the non-sunken sections is 1.0 or greater.

Description

Mat material, exhaust gas purification device, and method for manufacturing exhaust gas purification device

The present invention relates to a mat material, an exhaust gas purification device, and a method for manufacturing an exhaust gas purification device.

Exhaust gas emitted from internal combustion engines such as diesel engines contains particulate matter (hereinafter also referred to as PM), and in recent years, it has become a problem that this PM is harmful to the environment and the human body. . Moreover, since the exhaust gas also contains harmful gas components such as CO, HC, and NOx, there are concerns about the effects of these harmful gas components on the environment and the human body.

Here, as an exhaust gas purification device that collects PM in exhaust gas and purifies harmful gas components, an exhaust gas treatment body made of porous ceramic such as silicon carbide or cordierite and an exhaust gas treatment body are housed. Various exhaust gas purification devices have been proposed that include a casing and a mat material made of an inorganic fiber aggregate disposed between an exhaust gas treatment body and the casing. This type of mat material is used to prevent the exhaust gas treatment body from coming into contact with the casing that covers its outer periphery and damage it due to vibrations and shocks caused by driving, etc., and to prevent damage between the exhaust gas treatment body and the casing. The main purpose is to prevent exhaust gas from leaking.

The mat material is made of inorganic fibers, and the basic shape of the mat material when viewed from above is a rectangular shape consisting of a long side extending in the longitudinal direction and a short side substantially perpendicular to the long side, and one short side of the rectangle A concave portion is formed on the other short side, and a convex portion having a shape similar to the shape cut by the concave portion is formed on the other short side, and the mat material is wrapped around the exhaust gas treatment body to remove the convex portion. By fitting into the recess, exhaust gas is prevented from leaking from the mat material.
The exhaust gas treatment body wrapped with the mat material is press-fitted into the casing and assembled into the exhaust gas purification device.

For example, Patent Document 1 discloses that by using a sheet material (mat material) having an average unevenness difference h in the range of 0.4 mm≦h≦9 mm on the first surface, the sheet material and another member can be separated. It is disclosed that by reducing the contact area of the sheet material, it becomes possible to easily install the sheet material in a predetermined position without using a surface lubricant.

Japanese Patent Application Publication No. 2011-241837

Patent Document 1 does not mention anything about the detailed dimensions of the concave portion and the convex portion, and when the mat material was prepared and press-fitted, a portion of the mat material disposed on the most upstream side of the fitting portion was deformed. When the exhaust gas treatment body is fixed in a predetermined position, a part of the mat material may protrude from the casing.

The present invention was made to solve the above problems, and an object of the present invention is to provide a mat material that is less likely to protrude from a casing during press-fitting.

That is, the mat material of the present invention is a mat material containing inorganic fibers and having a substantially rectangular shape in a plan view, and the mat material has a first main surface and a second main surface facing each other in the thickness direction, and a winding direction. a first end face and a second end face facing each other in the longitudinal direction, and a first side face and a second side face facing each other in the thickness direction and the width direction perpendicular to the longitudinal direction; In some cases, a convex portion that protrudes toward the second end surface and non-protruding portions that are arranged on both sides of the convex portion in the width direction and do not protrude toward the second end surface are formed. The two end faces include a recess corresponding to the shape of the convex part of the first end face, and a recess that is arranged on both sides of the recess in the width direction and corresponds to the shape of the non-protruding part of the first end face. A non-concave part is formed, and the ratio [D/C] of the length [D] of the non-concave part in the width direction to the length [C] of the non-concave part in the longitudinal direction is , 1.0 or more.

When a mat material having corresponding convex portions and concave portions as described in Patent Document 1 is wound around an exhaust gas treatment body, at the fitting portion where the end surfaces of the mat material fit together, part of the first end surface and A portion of the second end surface is alternately arranged.
A portion of the first end surface is a convex portion provided on the first end surface, and a portion of the second end surface is a non-concave portion provided on the second end surface. There are two non-concave portions on the second end surface, one of which is disposed on the first side and the other on the second side. At the time of winding, the shapes of the convex portion of the first end surface and the concave portion of the second end surface correspond to each other, and the shapes of the non-protruding portion of the first end surface and the non-concave portion of the second end surface correspond to each other.
When the mat material is press-fitted into the casing, shear stress is generated between the exhaust gas treatment body and the casing, so that the mat material tends to be deformed so as to be pulled upstream in the press-fitting direction. This deformation is particularly likely to occur in a non-concave portion where there is no configuration that prevents deformation further upstream, that is, in a non-concave portion located furthest upstream.

It is considered that the non-sinking portion is less likely to be deformed by shear force as it is closer to the mat material main body (portions other than the convex portions and non-sinking portions), and the farther from the mat material main body is, the more likely it is to be deformed due to shear force. That is, it can be said that the shorter the length of the non-sinking portion, the more difficult the non-sinking portion is to deform.
On the other hand, as the width of the non-concave portion (distance equivalent to the length from the first side surface or the second side surface to the concave portion) increases, the area where the non-concave portion is fixed to the mat material body becomes longer, so that shearing It can be said that deformation due to this phenomenon is less likely to occur.
That is, it is considered that the ease with which the non-sinking portion deforms can be improved by adjusting the length and width of the non-sinking portion.
Further, even if there are a plurality of convex portions on the first end surface and a plurality of concave portions on the second end surface, the above-mentioned effects can be obtained.

In the mat material of the present invention, the ratio [D/C] of the length [D] of the non-recessed portion in the width direction to the length [C] of the non-recessed portion in the longitudinal direction is 1.0 or more.
In the above structure, compared to the structure of Patent Document 1, the length [C] of the non-sinking part in the longitudinal direction is relatively short, and the length [D] of the non-sinking part in the width direction is relatively long. It can be said that it has a good configuration.
Therefore, when the shape of the mat material satisfies the above conditions, the non-concave portion becomes difficult to deform due to the shear force during press-fitting, and becomes difficult to protrude from the casing.

The mat material of the present invention is preferably a needle mat.

In the mat material of the present invention, the mat material has a plurality of intertwined points formed by needling on at least one of the front surface or the back surface, and within a 25 mm x 25 mm area, there is a 4 mm x 4 mm area in which the above intertwined points are not present. It is preferable that at least one of the first region, which is the region, and the second region, which is the region of 3 mm x 8 mm where the intersecting point does not exist, is arranged.
When the first region and/or the second region are arranged within a 25 mm x 25 mm area, the surface pressure of the mat material can be increased.

In the mat material of the present invention, the average fiber length of the inorganic fibers is preferably 1 to 150 mm.

The mat material of the present invention is preferably a paper-made mat.

In the mat material of the present invention, the average fiber length of the inorganic fibers is preferably 200 to 20,000 μm.

In the mat material of the present invention, it is preferable that an inorganic binder is attached to the surface of the inorganic fibers.
When an inorganic binder is attached to the surface of the inorganic fiber, the frictional resistance between the inorganic fibers increases due to the inorganic binder attached to the surface of the inorganic fiber, so that the holding force can be increased.

In the mat material of the present invention, it is preferable that an organic binder is attached to the surface of the inorganic fiber.
When an organic binder is attached to the surface of the inorganic fibers, it is possible to improve the adhesion between the inorganic fibers and prevent the inorganic fibers from scattering during handling of the mat material.

In the mat material of the present invention, it is preferable that an inorganic binder and an organic binder are attached to the surface of the inorganic fibers.
When an inorganic binder is attached to the surface of the inorganic fiber, the frictional resistance between the inorganic fibers increases due to the inorganic binder attached to the surface of the inorganic fiber, so that the holding force can be increased.
Further, when an organic binder is attached to the surface of the inorganic fibers, the adhesion between the inorganic fibers can be improved, and it is possible to prevent the inorganic fibers from scattering during handling of the mat material.

The mat material of the present invention preferably further contains a polymeric dispersant.
When the mat material further contains a polymeric dispersant, the organic binder and the inorganic binder can be easily attached to the surface of the inorganic fibers in a dispersed state.

In the mat material of the present invention, it is preferable that the inorganic binder and the organic binder are attached to the surface of the inorganic fibers in a dispersed state.
When the inorganic binder and the organic binder are attached to the surface of the inorganic fiber in a dispersed state, the inorganic binder becomes dispersed in the film formed by the organic binder. Since the coating in this state has excellent mechanical strength, it can prevent the inorganic fibers from slipping against each other and increase the holding power.

In the mat material of the present invention, it is preferable that an aggregate made of the inorganic binder and the organic binder is attached to the surface of the inorganic fiber.
When an aggregate consisting of an inorganic binder and an organic binder is attached to the surface of inorganic fibers, it is possible to increase the friction between the inorganic fibers and improve the holding power.

In the mat material of the present invention, it is preferable that at least a portion of the surface of the inorganic fibers be covered with a coating layer made of a mixture of the inorganic binder and the organic binder.
A coating layer made of a mixture of an inorganic binder and an organic binder has higher mechanical strength than a coating layer made only of an organic binder. Therefore, the coating layer is less likely to peel off, and the frictional resistance between the inorganic fibers can be increased.

In the mat material of the present invention, it is preferable that the coating layer is formed by a continuous scale-like mixture of the inorganic binder and the organic binder.
When the coating layer is formed of the above-mentioned scale-like mixture, the surface roughness of the coating layer increases due to the scale-like mixture, so that the frictional resistance between the inorganic fibers can be further increased.

In the mat material of the present invention, the coating layer preferably has a multi-stage shape.
When the coating layer has a multi-stage shape, the frictional resistance between the inorganic fibers can be further increased.

In the mat material of the present invention, it is preferable that a particulate mixture of the inorganic binder and the organic binder adhere to the surface of the coating layer.
When a particulate mixture of an inorganic binder and an organic binder is attached to the surface of the coating layer, the frictional resistance between the inorganic fibers can be further increased compared to the case where the coating layer is used alone.

In the mat material of the present invention, the ratio [A/C] of the length [A] of the mat material in the longitudinal direction to the length [C] of the non-concave portion in the longitudinal direction is 10 or more. preferable.
If the ratio [A/C] of the length [A] of the mat material in the longitudinal direction to the length [C] of the non-sinking part in the longitudinal direction is within the above range, the shape of the non-sinking part will be deformed during press-fitting. It becomes a difficult shape.

The exhaust gas purification device of the present invention is an exhaust gas purification device having a casing, an exhaust gas treatment body, and a mat material disposed between the casing and the exhaust gas treatment body, wherein the mat material is the mat of the present invention. It is characterized by being made of wood.

Since the exhaust gas purification device of the present invention includes the mat material of the present invention, the mat material does not protrude during press-fitting, and the exhaust gas treatment body has excellent stability.

The method for manufacturing an exhaust gas purification device of the present invention includes a press-fitting step in which the mat material of the present invention is wound around an exhaust gas treatment body and then press-fitted into a casing by a hard stuffing method, a pre-calibration method, or a post-calibration method. It is characterized by comprising.

The hard stuffing method, pre-calibration method, and post-calibration method all require a step of press-fitting an exhaust gas treatment body wrapped with a mat material into a casing. Therefore, the mat material of the present invention can suppress displacement and deformation of the mat material during press-fitting, and is therefore particularly suitable for the above method.

FIG. 1 is a perspective view schematically showing an example of a mat material according to the present invention. FIG. 2 is a perspective view schematically showing an example of the process of winding the mat material shown in FIG. 1 around an exhaust gas treatment body. FIG. 3 is a perspective view schematically showing an example of a wound body prepared in the process shown in FIG. 2. FIG. 4 is a schematic diagram showing an example of a press-fitting process of press-fitting the wound body shown in FIG. 3 into a casing. FIG. 5 is a schematic diagram showing an example of the arrangement of intertwining points in the mat material of the present invention. FIG. 6 is a schematic diagram showing an example of a mat material in which intertwining points are uniformly arranged. FIG. 7 is an example of an enlarged electron microscope image of the mat material of the present invention. FIG. 8 is another example of an enlarged electron microscope image of the mat material of the present invention. FIG. 9 is yet another example of an enlarged electron microscope image of the mat material of the present invention. FIG. 10 is yet another example of an enlarged electron microscope image of the mat material of the present invention. FIG. 11 is a conceptual diagram schematically showing a shear failure load test device. FIG. 12 is a cross-sectional view schematically showing an example of the exhaust gas purification device of the present invention.

Embodiments of the present invention will be specifically described below. However, the present invention is not limited to the following embodiments, and can be modified and applied as appropriate without changing the gist of the present invention.

[Matt material]
The mat material of the present invention is a substantially rectangular mat material in a plan view containing inorganic fibers, and the mat material has a first main surface and a second main surface facing each other in the thickness direction, and a longitudinal direction in the winding direction. It has a first end face and a second end face facing each other in the direction, and a first side face and a second side face facing each other in the width direction perpendicular to the thickness direction and the longitudinal direction, and the first end face has a side surface that faces the width direction perpendicular to the thickness direction and the longitudinal direction. A convex portion that protrudes toward the second end surface, and non-protruding portions that are arranged on both sides of the convex portion in the width direction and do not protrude toward the second end surface are formed, and the second end surface At the time of winding, a recess corresponding to the shape of the convex part of the first end face, and a non-concave part arranged on both sides of the recess in the width direction and corresponding to the shape of the non-protruding part of the first end face. A recessed portion is formed, and a ratio [D/C] of the length [D] of the non-recessed portion in the width direction to the length [C] of the non-recessed portion in the longitudinal direction is 1. .0 or more.

FIG. 1 is a perspective view schematically showing an example of a mat material according to the present invention.
As shown in FIG. 1, the mat material 10 has a first main surface 11 and a second main surface 12 that face each other in the thickness direction (the direction indicated by the double-headed arrow T in FIG. 1), and a longitudinal direction (the direction in which it is wrapped) The first end surface 13 and the second end surface 14 face each other in the direction shown by double arrow A in FIG. 1), and the second end surface 14 faces each other in the width direction (direction shown by double arrow B in FIG. It has a substantially rectangular flat plate shape when viewed from above, and has a first side surface 15 and a second side surface 16.

The length of the mat material 10 is the length indicated by the double-headed arrow A in FIG.
The width of the mat material 10 is the length indicated by the double-headed arrow B in FIG.
The thickness of the mat material 10 is the length indicated by the double-headed arrow T in FIG.

The first end surface 13 includes a convex portion 13a that protrudes toward the second end surface 14 during winding, and

non-protrusive portions

13b and 13c that do not protrude toward the second end surface 14, which are disposed on both sides of the convex portion 13a in the width direction. is formed.

The second end face 14 has a recess 14a corresponding to the shape of the convex part 13a of the first end face 13 during winding, and

non-protruding parts

13b and 13c of the first end face 13 arranged on both sides of the recess 14a in the width direction.

Non-concave portions

14b and 14c corresponding to the shapes are formed.

The length of the convex portion 13a in the longitudinal direction (hereinafter also simply referred to as the length of the convex portion 13a) is the length indicated by the double arrow C.
The shape of the convex portion 13a corresponds to the shape of the concave portion 14a. Therefore, the length of the recess 14a in the longitudinal direction (hereinafter also simply referred to as the length of the recess 14a) is the length shown by the double arrow C.

The length of the recess 14a in the width direction (hereinafter also simply referred to as the width of the recess 14a) is the length shown by the double arrow E.
The shape of the concave portion 14a corresponds to the shape of the convex portion 13a. Therefore, the length of the protrusion 13a in the width direction (hereinafter also simply referred to as the width of the protrusion 13a) is the length indicated by the double arrow E.
Further, the center of the convex portion 13a in the width direction coincides with the center of the concave portion 14a in the width direction.

The length of the

non-sinking portions

14b, 14c in the longitudinal direction (hereinafter also simply referred to as the length of the

non-sinking portions

14b, 14c) is the length indicated by the double-headed arrow C, the same as the length of the recess 14a in the longitudinal direction. .
Further, the length of the

non-sinking portions

14b, 14c in the width direction (hereinafter also simply referred to as the width of the

non-sinking portions

14b, 14c) is the length indicated by the double-headed arrow D.
The length of the

non-protruding parts

13b, 13c in the width direction (hereinafter also simply referred to as the width of the

non-protruding parts

13b, 13c) is the same as the length of the

non-recessed parts

14b, 14c in the width direction, as indicated by the double-headed arrow D. It is.

The portion of the mat material 10 excluding the convex portion 13a and the

non-concave portions

14b and 14c is also referred to as the main body portion of the mat material.

The length [A] of the mat material in the longitudinal direction corresponds to the length from the first end surface to the second end surface in each cross section when the mat material is cut along a plane parallel to the longitudinal direction and the thickness direction. do.

In the mat material 10 shown in FIG. 1, when the length of the

non-sinking parts

14b, 14c in the longitudinal direction is [D], and the length of the

non-sinking parts

14b, 14c in the width direction is [C], The ratio [D/C] of the length [D] of the

non-concave portions

14b, 14c to the length [C] of the

non-concave portions

14b, 14c in the width direction is 1.0 or more.
Note that the ratio [D/C] in the mat material 10 shown in FIG. 1 is 2.1.

As described above, the length of the recessed portion 14a in the longitudinal direction is the same as the length of the

non-depressed portions

14b and 14c in the longitudinal direction.
Further, the length of the recess 14a in the longitudinal direction is the same as the length of the protrusion 13a in the longitudinal direction. Further, the lengths of the

non-concave portions

14b, 14c in the width direction are the same as the lengths of the

non-protrusion portions

13b, 13c in the width direction.

From the above, the mat material according to the present invention has a ratio [D/C] of the length [D] of the non-concave part in the width direction to the length [C] of the non-concave part in the longitudinal direction of 1.0 or more. ” can also be rephrased as “the ratio [D/C] of the length [D] of the non-protruding portion in the width direction to the length [C] of the convex portion in the longitudinal direction is 1.0 or more.” .

In the mat material according to the present invention, the ratio [D/C] of the length [D] of the non-depressed portion in the width direction to the length [C] of the non-depressed portion in the longitudinal direction is preferably 1.2 or more. It is preferably 1.6 or more, and more preferably 1.6 or more.

In the mat material according to the present invention, the center [E _C ] of the recess in the width direction may or may not overlap the center [B _C ] of the mat material in the width direction.

In the mat material 10 shown in FIG. 1, the center [E _C ] of the recess 14a in the width direction overlaps with the center [B _C ] of the mat material 10 in the width direction.
Therefore, the width of the non-sinking portion 14c is the same as the width of the non-sinking portion 14b, which is the length indicated by the double-headed arrow D. Further, the width of the non-protruding portion 13c is the same as the width of the non-protruding portion 13b, which is the length indicated by the double-headed arrow D.

If the widthwise center [E _C ] of the concave portion does not overlap the widthwise center [B _C ] of the mat material, the widths of the two non-concave portions do not match. The width of one non-recessed portion is shorter than the width of the other non-recessed portion.
At this time, the ratio [D/C] of the length [D] of the non-concave part in the width direction to the length [C] of the non-concave part in the longitudinal direction is calculated. Adopt the length of the non-sinking part.

FIG. 2 is a perspective view schematically showing an example of the process of winding the mat material shown in FIG. 1 around an exhaust gas treatment body. FIG. 3 is a perspective view schematically showing an example of a wound body prepared in the process shown in FIG. 2.

As shown in FIG. 2, by winding the mat material 10 around the exhaust gas treatment body 230, a wrapped body 250 shown in FIG. 3 is obtained.

In addition, in FIG. 2, the mat material 10 is wound so that the first main surface 11 of the mat material 10 is in contact with the exhaust gas treatment body 230, but the second main surface 12 of the mat material 10 is in contact with the exhaust gas treatment body 230. It may be wrapped like this.

FIG. 4 is a schematic diagram showing an example of a press-fitting process of press-fitting the wound body shown in FIG. 3 into a casing.
FIG. 4 shows how the wrapped body 250 shown in FIG. 3 is press-fitted into the casing 220.
The direction in which the wrapped body 250 is press-fitted is from the top to the bottom of the paper.
Therefore, of the two side surfaces (first side surface 15 and second side surface 16) of the mat material 10, the second side surface 16 is arranged on the downstream side in the press-fitting direction, and the first side surface 15 is arranged on the upstream side in the press-fitting direction. It can be said that

When the wrapped body 250 is press-fitted into the casing 220, a large shearing force is applied to the mat material 10 due to the friction between the mat material 10 and the casing 220 and the friction between the mat material 10 and the exhaust gas treatment body 230.
Specifically, a force is applied that pulls the surface of the mat material 10 constituting the wrapped body 250 toward the upstream side in the press-fitting direction.

The magnitude of deformation of the convex portions and non-concave portions due to shear force is determined by the order of arrangement in the press-fitting direction and the connection area (distance) with the portion that will become the main body of the mat material.
That is, the more upstream in the press-fitting direction, the greater the deformation, and the shorter the connection area (distance) between the mat material and the main body, the greater the deformation.

In the wrapped body 250 shown in FIG. 4, the non-concave portion 14b of the mat material 10 is the most upstream portion in the press-fitting direction, and is a portion that is easily deformed by shear force.
However, in the mat material according to the present invention, the ratio [D/C] of the length [D] of the non-depressed portion in the width direction to the length [C] of the non-depressed portion in the longitudinal direction is 1.0 or more. Therefore, regardless of the orientation of the mat material, it is possible to suppress deformation of the non-concave portion disposed on the upstream side in the press-fitting direction.

In the mat material according to the present invention, the arrangement of the two side surfaces of the mat material in the press-fitting process is not particularly limited. Therefore, as shown in FIG. 4, the second side surface may be disposed on the downstream side in the press-fitting direction, and the first side surface may be disposed on the upstream side in the press-fitting direction, or the first side surface may be disposed on the downstream side in the press-fitting direction, and the second side surface may be disposed on the downstream side in the press-fitting direction. may be arranged on the upstream side in the press-fitting direction.
However, if the center of the recess in the width direction does not overlap the center of the mat material in the width direction, the side surface of the mat material where the non-concave part with the short width direction is arranged will be on the downstream side in the press-fitting direction. It is preferable that the side surface of the mat material on which the non-concave portion having a long length in the width direction is disposed is disposed on the upstream side in the press-fitting direction. By arranging the mat material in the above-mentioned direction, deformation of the non-concave portion located on the upstream side in the press-fitting direction can be further suppressed.

For example, assuming that the center of the recess in the width direction does not overlap the center of the mat material in the width direction, the mat material will have two non-concave portions with different lengths.
In this case, if the width of one non-depressed part is D ₁ and the width of the other non-depressed part is D ₂ and D ₁ > D ₂ , then the width of the non-depressed part with the shorter width, that is, the width of the other non-depressed part is D 1 . If the ratio [D ₂ /C] of the length [D ₂ ] of the non-sinking portion in the width direction of D ₂ to the length [C] of the non-sinking portion in the longitudinal direction is 1.0 or more, the present invention is applicable. Included in mat material. This is because, since D ₁ >D ₂ , if [D ₂ /C] is 1.0 or more, naturally [D ₁ /C] will also be 1.0 or more.
When the side surface of the mat material with a non-sinking portion having a width of D ₂ is placed on the upstream side in the press-fitting direction, the condition that [D ₂ /C] is 1.0 or more is satisfied, so deformation of the non-sinking portion is suppressed. be done.
When the side surface of the mat material having a non-concave portion with a width of D ₁ is placed on the upstream side in the press-fitting direction, [D ₁ /C] is 1.0 or more and a value larger than [D ₂ /C]. Therefore, the deformation of the non-sinking portion is further suppressed than when the side surface of the mat material including the non-sinking portion having a width of _D2 is disposed on the upstream side in the press-fitting direction.

In the mat material of the present invention, the ratio [A/C] of the length [A] of the mat material in the longitudinal direction to the length [C] of the non-concave part in the longitudinal direction is not particularly limited, but it should be 10 or more. is preferred.

If the ratio [A/C] of the length [A] of the mat material in the longitudinal direction to the length [C] of the non-sinking part in the longitudinal direction is 10 or more, the shape of the non-sinking part will be deformed during press-fitting. It becomes a difficult shape.
Note that the ratio [A/C] in the mat material 10 shown in FIG. 1 is 10.1.

As described above, the length [C] of the non-concave portion in the longitudinal direction is the same as the length [C] of the concave portion and the length [C] of the convex portion in the longitudinal direction.
Therefore, the feature of the mat material of the present invention is that "the ratio [A/C] of the length [A] of the mat material in the longitudinal direction to the length [C] of the non-concave part in the longitudinal direction is 10 or more.""The ratio [A/C] of the length [A] of the mat material in the longitudinal direction to the length [C] of the convex part in the longitudinal direction is 10 or more" or "The length of the mat material in the longitudinal direction In other words, the ratio [A/C] of the length [A] to the length [C] of the recess in the longitudinal direction is 10 or more.

Note that in the mat material 10 shown in FIGS. 1 to 4, one convex portion 13a is formed on the first end surface 13 and one concave portion 14a is formed on the second end surface 14, but in the mat material of the present invention, The number of protrusions formed on the first end surface and the number of recesses formed on the second end surface of the mat material may be two or more.
In this case, focusing on the non-sinking part located closest to the first side surface of the mat material and the non-sinking part located closest to the second side surface, the length in the width direction of the non-sinking part is The ratio [D/C] between the length [D] and the length [C] in the length direction of the non-sinking portion is determined.
The above-mentioned ratio [D/C] in the non-concave part located at the position closest to the first side surface of the mat material and the above-mentioned ratio [D/C] at the non-concave part located at the position closest to the second side surface of the mat material C] of 1.0 or more corresponds to the mat material of the present invention.

In the mat material according to the present invention, the thickness of the mat material is not particularly limited, but is preferably 2 to 40 mm. If the thickness of the mat material exceeds 40 mm, the mat material loses its flexibility, making it difficult to handle when wrapping the mat material around an exhaust gas treatment body. In addition, the mat material tends to wrinkle and crack.
If the thickness of the mat material is less than 2 mm, the holding power of the mat material will be insufficient and the exhaust gas treatment body will easily fall off. Further, when a volume change occurs in the exhaust gas treatment body, the mat material becomes difficult to absorb the volume change of the exhaust gas treatment body. Therefore, cracks and the like are likely to occur in the exhaust gas treatment body.

The mat is composed of inorganic fibers.

Although the inorganic fiber is not particularly limited, it is preferable that the inorganic fiber is composed of at least one selected from the group consisting of alumina fiber, silica fiber, alumina-silica fiber, mullite fiber, biosoluble fiber, and glass fiber.
When the inorganic fiber is at least one of alumina fiber, silica fiber, alumina-silica fiber, and mullite fiber, it has excellent heat resistance, so that when the exhaust gas treatment body is exposed to a sufficiently high temperature, However, no deterioration or the like occurs, and the function as a mat material can be sufficiently maintained. In addition, if the inorganic fibers are biosoluble fibers, even if the scattered inorganic fibers are inhaled when making an exhaust gas purification device using the mat material, they will dissolve in the body, making it difficult for workers to use them. No harm to health.

In addition to alumina, the alumina fiber may contain additives such as calcia, magnesia, and zirconia.
The composition ratio of the alumina-silica fibers is preferably Al ₂ O ₃ :SiO ₂ =60:40 to 80:20 in terms of weight ratio, and Al ₂ O ₃ :SiO ₂ =70:30 to 74:26. It is more preferable.

The mat can be manufactured by a needling method or a papermaking method. Mats produced by the needling method are also referred to as needle mats, and mats produced by the papermaking method are also referred to as papermaking mats.

In the case of the needling method, the average fiber length of the inorganic fibers is preferably 1 to 150 mm, more preferably 10 to 80 mm.
If the average fiber length of the inorganic fibers is less than 1 mm, the fiber length of the inorganic fibers will be too short, resulting in insufficient entanglement of the inorganic fibers, reducing the ability to wrap around the exhaust gas treatment body, and making the mat material more likely to crack. . Furthermore, when the average fiber length of the inorganic fibers exceeds 150 mm, the fiber length of the inorganic fibers is too long, so the number of fibers constituting the mat material decreases, and the denseness of the mat material decreases. As a result, the shear strength of the mat material decreases.

In the case of the papermaking method, the average fiber length of the inorganic fibers is preferably 200 to 20,000 μm, more preferably 300 to 10,000 μm, and even more preferably 500 to 1,500 μm.

In the case of the needling method, intertwined points are formed on the front or back surface of the mat material.
The density ρ of the intertwined points is preferably in the range of 0.5 pieces/cm ² ≦ρ<18 pieces/cm ² .
In addition, when interlacing points are formed on both the front and back surfaces of the mat material, the density ρ of the interlacing points is the interlacing points measured on the main surface of the front or back surface, whichever has a higher density of interlacing points. Let the density be

In the case of the needling method, within a 25 mm x 25 mm area on the front or back side of the mat material, there is a first area of 4 mm x 4 mm in which no intertwined points exist, and a 3 mm x 8 mm area in which no intertwined points exist. It is preferable that at least one of the second regions is arranged.
By arranging at least one of the first region and the second region, high surface pressure is exerted.
Note that the main surface of the mat material for determining whether the first region and/or the second region is arranged is the same main surface as the main surface for measuring the density of the intertwining points.

FIG. 5 is a schematic diagram showing an example of the arrangement of intertwining points in the mat material of the present invention.
The mat material 10 shown in FIG. 5 has dimensions of 25 mm x 25 mm in plan view.
In FIG. 5, a plurality of interlacing points 115 are arranged unevenly. Therefore, the first area 117 is a 4 mm x 4 mm area (the area indicated by the solid square in FIG. 5) where the interlacing point 115 does not exist, and the 3 mm x 8 mm area (indicated by the solid square in FIG. 5) where the intersecting point 115 does not exist. , a region indicated by a dashed rectangle) is arranged.
Note that FIG. 5 does not illustrate all of the first region 117 and the second region 118.

FIG. 6 is a schematic diagram showing an example of a mat material in which intertwining points are uniformly arranged.
The mat material 10 shown in FIG. 6 has dimensions of 25 mm x 25 mm in plan view.
In FIG. 6, the interlacing points 115 are uniformly spaced at 2.8 mm intervals.
Both the 4 mm x 4 mm square and the 3 mm x 8 mm rectangle shown in FIG. 6 include one or more intertwining points. A square of 4 mm x 4 mm that does not correspond to the first area and a rectangle of 3 mm x 8 mm that does not correspond to the second area are marked with an "x".
Therefore, neither the first region nor the second region can be arranged on the mat material shown in FIG. 6 .

The method for counting the number of first areas and second areas within a 25 mm x 25 mm area is as follows.
(1) Find a 4 mm x 4 mm area (first area) in which no intertwined points are formed. At this time, the plurality of first regions are selected so that they do not overlap with each other.
(2) Find a 3 mm x 8 mm area (second area) in which no intertwined points are formed. At this time, the plurality of second regions are selected so that they do not overlap with each other. However, the second area may overlap the first area. When the second region and the first region overlap, the area where no intertwining points are present becomes larger, so that the surface pressure of the mat material can be increased.
(3) Select a region of 25 mm x 25 mm in which the number of first regions that do not overlap with each other and the number of second regions that do not overlap with each other are maximum.
The above operation is performed on 10 samples and the average value is taken.
Note that the above operation may be performed using commercially available image processing software.

Preferably, a plurality of first regions and/or second regions are arranged in a 25 mm x 25 mm area.
When a plurality of first regions and/or second regions are arranged within a region of 25 mm x 25 mm, the surface pressure of the mat material can be increased.
A plurality of first regions and/or second regions are arranged when the number of first regions and the number of second regions is two or more in total, and a plurality of first regions are arranged. This includes a case where a plurality of second regions are arranged, a case where a plurality of first regions and a plurality of second regions are arranged, and the like.

It is preferable that a third area, which is a 4 mm x 4 mm area in which four or more interlacing points exist, is arranged within a 25 mm x 25 mm area on the front or back surface of the mat material.
When the third region is provided, the inorganic fibers are strongly intertwined with each other in this region, so that the shear strength of the mat material can be increased.
Note that the method for counting the number of third regions within the 25 mm x 25 mm region is the same as the method for counting the number of first regions described above.

It is preferable that an inorganic binder (also referred to as an inorganic binder) is attached to the surface of the inorganic fiber.
When an inorganic binder is attached to the surface of the inorganic fiber, the frictional resistance between the inorganic fibers increases due to the inorganic binder attached to the surface of the inorganic fiber, so that the holding force can be increased.

Examples of the inorganic binder include alumina sol and silica sol.

It is preferable that an organic binder (also referred to as an organic binder) is attached to the surface of the inorganic fiber.
When an organic binder is attached to the surface of the inorganic fibers, it is possible to improve the adhesion between the inorganic fibers and prevent the inorganic fibers from scattering during handling of the mat material.

Examples of the organic binder include acrylic resin, acrylate latex, rubber latex, water-soluble organic polymers such as carboxymethyl cellulose or polyvinyl alcohol, thermoplastic resins such as styrene resin, and thermosetting resins such as epoxy resin.

Preferably, an inorganic binder and an organic binder are attached to the surface of the inorganic fiber.
When an inorganic binder is attached to the surface of the inorganic fiber, the frictional resistance between the inorganic fibers increases due to the inorganic binder attached to the surface of the inorganic fiber, so that the holding force can be increased.
Further, when an organic binder is attached to the surface of the inorganic fibers, the adhesion between the inorganic fibers can be improved, and it is possible to prevent the inorganic fibers from scattering during handling of the mat material.

The weight ratio of the inorganic binder to the mat material (weight of inorganic binder/weight of mat material) is preferably more than 0 wt% and 10 wt% or less.
When the weight ratio of the inorganic binder to the mat material is within the above range, the holding force can be sufficiently increased.

The weight ratio of the organic binder to the mat material (weight of organic binder/weight of mat material) is preferably more than 0 wt% and 10 wt% or less.
When the weight ratio of the organic binder to the mat material is within the above range, both the effect of preventing fiber scattering and the high holding power can be achieved.

The content of the organic binder and inorganic binder contained in the mat material can be measured, for example, by the following method.
First, a fixed weight sample of the mat material whose content is to be measured is taken. Next, an organic solvent (for example, tetrahydrofuran) in which the organic binder contained in the sample is dissolved is selected, and the organic binder is dissolved in a Soxhlet extractor and separated from the sample. At this time, the inorganic binder contained in the dissolved organic binder is also separated from the sample, and the organic binder and the inorganic binder are recovered in the organic solvent.
Next, an organic solvent consisting of the organic binder and the inorganic binder is placed in a crucible, and the organic solvent is evaporated off by heating. The residue remaining in the crucible is regarded as the total weight of the organic binder and the inorganic binder relative to the mat material, and the content (% by weight) relative to the weight of the mat material is calculated.
Furthermore, the crucible is heat-treated at 600° C. for 1 hour to burn out the organic binder. Since the inorganic binder remains in the crucible, this is regarded as the content (% by weight) of the inorganic binder relative to the total of the organic binder and the inorganic binder, and the content is calculated. The remainder is the content (% by weight) of the organic binder.

In the mat material, it is preferable that the inorganic binder and the organic binder are each attached to the surface of the inorganic fibers in a dispersed state.
When the inorganic binder and the organic binder are attached to the surface of the inorganic fiber in a dispersed state, the inorganic binder becomes dispersed in the film formed by the organic binder. Since the coating in this state has excellent mechanical strength, it can prevent the inorganic fibers from slipping against each other and increase the holding power.

In the mat material, it is preferable that at least a portion of the surface of the inorganic fibers be covered with a coating layer made of a mixture of an inorganic binder and an organic binder.
A coating layer made of a mixture of an inorganic binder and an organic binder has higher mechanical strength than a coating layer made only of an organic binder. Therefore, the coating layer is less likely to peel off, and the frictional resistance between the inorganic fibers can be increased.

The coating layer is preferably formed by a continuous scale-like mixture (a mixture of an inorganic binder and an organic binder).
When the coating layer is formed of the above-mentioned scale-like mixture, many irregularities derived from the scale-like mixture are formed on the surface of the coating layer, and the frictional resistance between the inorganic fibers can be further increased.

FIG. 7 is an example of an enlarged electron microscope image of the mat material of the present invention.
As shown in FIG. 7, a part of the surface of the inorganic fiber 120 is covered with a coating layer 130 made of a mixture of an inorganic binder and an organic binder. The covering layer 130 is formed by a continuous scale-like mixture of an inorganic binder and an organic binder. A particulate mixture 140 of an inorganic binder and an organic binder is attached to the surface of the inorganic fiber 120 .
Note that whether or not the coating layer or particles are made of a mixture of an inorganic binder and an organic binder can be confirmed by combined use of field observation using an electron microscope and elemental analysis.

FIG. 8 is another example of an enlarged electron microscope image of the mat material of the present invention.
As shown in FIG. 8, a part of the surface of the inorganic fiber 120 is covered with a coating layer 130 made of a mixture of an inorganic binder and an organic binder. The covering layer 130 is formed by a continuous scale-like mixture of an inorganic binder and an organic binder. A particulate mixture 140 of an inorganic binder and an organic binder is attached to the surface of the inorganic fiber 120 .

The thickness of the coating layer may be uniform, but it does not need to be uniform.
The shape of the coating layer whose thickness is not constant is also called multistage.
When the covering layer has a multi-stage shape, it can be said that the covering layer has irregularities on the surface, so that the frictional resistance between the inorganic fibers can be further increased.
To determine whether the coating layer has irregularities on the surface, that is, whether the coating layer has a multi-step shape, the surface of the inorganic fiber is magnified 3000 times using a scanning electron microscope. This is determined by checking the presence or absence of irregularities on the surface.

FIG. 9 is yet another example of an enlarged electron microscope image of the mat material of the present invention.
As shown in FIG. 9, a part of the surface of the inorganic fiber 120 is covered with a coating layer 130 made of a mixture of an inorganic binder and an organic binder. The thickness of the covering layer 130 is not uniform, and is multi-stepped.
A particulate mixture 140 of an inorganic binder and an organic binder is attached to the surface of the inorganic fiber 120 .

Preferably, particles made of a mixture of an inorganic binder and an organic binder are attached to the surface of the coating layer.
When particles made of a mixture of an inorganic binder and an organic binder are attached to the surface of the coating layer, the frictional resistance between the inorganic fibers can be further increased compared to a case where the particles are not attached.

FIG. 10 is yet another example of an enlarged electron microscope image of the mat material of the present invention.
As shown in FIG. 10, a part of the surface of the inorganic fiber 120 is covered with a coating layer 130 made of a mixture of an inorganic binder and an organic binder. The covering layer 130 is formed by a continuous scale-like mixture of an inorganic binder and an organic binder. The thickness of the covering layer 130 is not uniform, and is multi-stepped. A particulate mixture 140 of an inorganic binder and an organic binder is attached to the surface of the coating layer 130 .

It is preferable that the mat material further contains a polymeric dispersant.
When the mat material further contains a polymeric dispersant, the organic binder and the inorganic binder can be easily attached to the surface of the inorganic fibers in a dispersed state.
The content of the polymeric dispersant is preferably 50 to 1000 ppm based on the weight of the inorganic fiber.

In the mat material, it is preferable that an aggregate made of an inorganic binder and an organic binder is attached to the surface of the inorganic fibers.
The aggregate made of the inorganic binder and the organic binder can form irregularities on the surface of the inorganic fibers, so that the friction between the inorganic fibers can be increased and the holding power can be improved.

The mat material may further contain an aggregating agent.
When the mat material further contains an aggregating agent, the organic binder and the inorganic binder can be easily attached to the surface of the inorganic fibers in an agglomerated state.

Whether the inorganic binder and organic binder attached to the surface of the inorganic fiber are dispersed or aggregated can be confirmed by observing the surface of the inorganic fiber using a SEM-EDX or the like.

The mat material of the present invention preferably has a shear coefficient of 0.20 or more.
When the shear coefficient is 0.20 or more, shearing is less likely to occur in the mat material when the exhaust gas treatment body is press-fitted into a casing using the mat material of the present invention.
The shear modulus is obtained by dividing the shear failure load by the relaxed surface pressure.

The shear failure load can be measured using a shear failure load testing device shown in FIG.
FIG. 11 is a conceptual diagram schematically showing a shear failure load test device.
In the shear fracture load testing device 170 shown in FIG. 11,

test pieces

1a and 1b are arranged on both sides of a stainless steel plate 173, and the outside thereof is further sandwiched between a left jig 171 and a right jig 172. A large number of protruding members 174 are provided on the surfaces of the left jig 171, the right jig 172, and the stainless steel plate 173 that contact the test piece.
The

test pieces

1a and 1b are fixed to the left jig 171, the right jig 172, and the stainless steel plate 173 by being pierced by the protruding member 174.
In this state, the test piece is compressed until its bulk density (GBD) becomes 0.3 g/cm ³ .
Next, when the stainless steel plate 173 is moved in the direction shown by the arrow in FIG. It cannot be separated from the

pieces

1a and 1b and come off. Therefore, when a shear force greater than the shear failure load of the test pieces is applied to the

test pieces

1a and 1b, the

test pieces

1a and 1b undergo shear failure.
Determine the shear force applied to the stainless steel plate when the test piece undergoes shear failure.

By dividing the obtained shear force by the area of the test piece, the shear failure load (kPa) can be determined. Note that the shear failure load may be measured using a test piece obtained by cutting out a portion of the mat material.

Relaxed surface pressure can be measured using the following procedure.
First, the mat material is compressed at room temperature until the bulk density becomes 0.3 g/cm ³ , and the load is measured after holding for 20 minutes.

By dividing the obtained load by the area of the test piece, the relaxed surface pressure (kPa) can be determined. Note that the above-mentioned relaxation surface pressure may be measured using a test piece obtained by cutting out a part of the mat material.

The surface pressure of the mat material after firing is preferably 50 kPa or more.
The surface pressure of the mat material after firing can be measured by the following method using a hot surface pressure measuring device equipped with a heater in the part of the plate that compresses the mat material to become the test piece.
First, a test piece (mat material) is compressed at room temperature until the bulk density becomes 0.3 g/cm ³ and then held for 10 minutes. After that, while the test piece is compressed, the temperature is increased to 900°C on one side and 650°C on the other side at a heating rate of 45°C, and the compression is released until the bulk density reaches 0.27 g/ ^cm3 , and held for 5 minutes. . Thereafter, a plate for compressing the mat material is moved at a speed of 1 inch (25.4 mm)/min to compress the mat material until the bulk density becomes 0.3/cm ³ . After repeating 1000 times of releasing compression until the bulk density becomes 0.27 g/cm ³ and compressing until the bulk density becomes 0.3 g/cm ³ , the bulk density becomes 0.27 g/cm ³ . Measure. By dividing the obtained load by the area of the test piece, the surface pressure (kPa) is obtained and is taken as the surface pressure after firing.

[Method for manufacturing mat material]
The mat material of the present invention can be obtained, for example, by performing a cutting step of cutting a mat containing inorganic fibers into a predetermined shape, or a molding step of molding it into a predetermined shape.

The mat can be obtained, for example, by a needling method and a papermaking method.

In the case of the needling method, for example, there is a spinning process in which an inorganic fiber precursor is produced by spinning a spinning mixture containing at least an inorganic compound and an organic polymer, and a sheet-like product is produced by compressing the inorganic fiber precursor. a compression step of performing a needle punching process on at least one surface of the sheet-like material to produce a needle-punched body, and a firing process of firing the needle-punched body. I can do it.
Specific examples of the spinning process, compression process, needle punching process, and firing process will be described below.

[Spinning process]
In the spinning step, an inorganic fiber precursor is produced by spinning a spinning mixture containing at least an inorganic compound and an organic polymer.
In the spinning step, for example, a spinning mixture made of a basic aluminum chloride aqueous solution, silica sol, etc. as raw materials is spun by a blowing method to produce an inorganic fiber precursor having an average fiber diameter of 3 to 10 μm.

[Compression process]
In the compression step, the inorganic fiber precursor obtained in the spinning step is compressed to produce a continuous sheet-like product of a predetermined size.

[Needle punching process]
In the needle punching process, a needle punching process is performed on at least one surface of the sheet-like material obtained in the compression process to produce a needle punched body.

In the needle punching step, the needle arrangement density is preferably set to 0.5 needles/cm ² or more and less than 18 needles/cm ² .
The positions where the needles are placed in the needle punching process correspond to the interlacing points in the mat. Therefore, by setting the needle arrangement density to 0.5 needles/cm ² or more and less than 18 needles/cm ² , one needle punching process can reduce the density of intertwined points ρ to 0.5 needles/cm ² ≦ρ Mats in the range <18 pieces/cm ² can be obtained.
However, when needle punching is performed multiple times on the same sheet-like material, the needle arrangement density is not limited to the above range.

In addition, by intentionally biasing the arrangement of the needles in the needle punching process, the arrangement of the intertwined points formed on the needle punched body is unevenly arranged, and the density ρ of the intertwined points is 0.5 pieces/cm. ² ≦ ρ < 18 pieces/cm ² , within a 25 mm x 25 mm area, a 4 mm x 4 mm area (first area) where no intersecting points exist and/or a 3 mm x 8 mm area where no intersecting points exist. A region (second region) can be formed.

An example of a method for intentionally biasing the arrangement of intertwined points is to perform needle punching so that the intertwined points are uniformly arranged, and then additionally perform needling in a portion. Other examples include a method in which needle punching is performed multiple times while moving the inorganic fiber precursor, and a method in which needle punching is performed using a needle board in which needles are not arranged at regular intervals.

In the needle punching step, the needles may or may not penetrate the sheet-like material in the thickness direction.

[Firing process]
In the firing step, the needle punched body is fired to obtain a mat made of inorganic fibers.
The temperature at which the needle punched body is fired is not particularly limited, but is preferably 1000°C to 1600°C.
Through the above steps, a mat can be obtained.

[Cutting process]
The mat material of the present invention can be obtained by cutting the mat obtained through the above steps into a predetermined shape.

In manufacturing the mat material of the present invention, an attachment step may be performed in which an inorganic binder and/or an organic binder is attached to the surface of the mat or the inorganic fibers constituting the mat material.

[Attachment process]
In the attachment step, an inorganic binder and/or an organic binder is attached to the mat.
When an inorganic binder and an organic binder are not distinguished, they are also simply referred to as a binder.

Examples of the inorganic binder include alumina sol and silica sol.

As a method for attaching the binder to the mat, for example, a method may be mentioned in which a binder liquid mixture in which a solvent and a binder are mixed is brought into contact with the mat, and then the mat is dried.
Examples of methods for bringing the binder mixture into contact with the mat include a method in which the mat is immersed in the binder mixture, and a method in which the binder mixture is dropped onto the mat using a method such as a curtain coating method.

The content of the inorganic binder in the binder mixture is preferably 0.05 wt% or more and 5 wt% or less.
The content of the organic binder in the binder mixture is preferably 0.05 wt% or more and 5 wt% or less.
That is, the binder mixture may contain only an inorganic binder, only an organic binder, or both an inorganic binder and an organic binder.

The binder mixture may contain a polymeric dispersant.
If the binder mixed liquid contains a polymeric dispersant, the binder will be in a dispersed state in the binder mixed liquid. By bringing the binder mixture in this state into contact with the mat, the binder can be attached to the surface of the inorganic fibers in a dispersed state.

Examples of polymeric dispersants include polycarboxylic acid and/or its salt, naphthalene sulfonate formalin condensate and/or its salt, polyacrylic acid and/or its salt, polymethacrylic acid and/or its salt, polyvinyl sulfone Hydrophilic synthetic polymer substances such as anionic polymer dispersants such as acids and/or their salts, nonionic polymer dispersants such as polyvinyl alcohol, polyvinylpyrrolidone, and polyethylene glycol; gelatin, casein, water-soluble Natural hydrophilic polymeric substances such as starch; hydrophilic semi-synthetic polymeric substances such as carboxymethyl cellulose, and the like.
Among these, hydrophilic synthetic polymer substances are preferred, and anionic polymer dispersants are more preferred.
Furthermore, only one type of these polymeric dispersants may be used, or a plurality of types may be used in combination. Further, it may be a polymeric dispersant having both a structure exhibiting properties as an anionic polymeric dispersant and a structure exhibiting properties as a nonionic polymeric dispersant.

The binder mixture may contain a flocculant.
If the binder mixed liquid contains an aggregating agent, the binder will be in a coagulated state in the binder mixed liquid. By bringing the binder mixture in this state into contact with the mat, the binder can be attached to the surface of the inorganic fibers in an aggregated state.

The binder mixture may contain a polymeric dispersant.
If the binder mixed liquid contains a polymeric dispersant, the binder will be in a dispersed state in the binder mixed liquid. That is, the binder mixed liquid becomes a dispersion liquid in which the binder is dispersed in a dispersion medium. By bringing the binder mixture (dispersion) in this state into contact with the mat, the binder can be attached to the surface of the inorganic fibers in a dispersed state.

The binder mixture may contain a flocculant.
If the binder mixture contains an aggregating agent, the binder will be in an agglomerated state in the mixture. That is, the binder liquid mixture becomes an agglomerated dispersion liquid in which aggregates formed by aggregating the binder are dispersed in a dispersion medium. By bringing the mixed liquid (agglomerated dispersion liquid) in this state into contact with the mat, the binder can be attached to the surface of the inorganic fibers in an aggregated state.

In the impregnation step, the inorganic binder and the organic binder may be applied separately.
As a method of impregnating an inorganic binder and impregnating an organic binder separately, for example, an inorganic binder mixture containing an inorganic binder is brought into contact with the mat to adhere the inorganic binder, and then an organic binder mixture containing an organic binder is applied. A method of attaching an organic binder by contacting with the organic binder can be mentioned. The order in which the inorganic binder and the organic binder are attached is not particularly limited, and the inorganic binder may come first or the organic binder may come first.

Through the above steps, it is possible to obtain the mat material of the present invention in which an inorganic binder and/or an organic binder is attached to the surface of inorganic fibers.

Next, the case of using the papermaking method will be explained.
In the case of the papermaking method, for example, a fiber opening step of opening inorganic fibers, a slurry preparation step of mixing the opened inorganic fibers with a solvent, an inorganic binder, and an organic binder to prepare a slurry, and a step of preparing the slurry. A mat can be obtained by a paper-making process of obtaining an inorganic fiber aggregate by paper-making and a drying process of drying the inorganic fiber aggregate.
Specific examples of the opening process, slurry preparation process, papermaking process, and drying process will be described below.

[Opening process]
In the opening process, the inorganic fibers are shortened (also referred to as opening) using a crusher such as a feather mill or an agitator such as a pulper, and adjusted to a desired fiber length.

The shortened inorganic fibers may be subjected to a classification treatment if necessary, and it is preferable to perform a classification treatment to remove some or all of the inorganic fibers having a fiber length of 200 μm or less.

Examples of the above-mentioned classification treatment include classification treatment using a dry centrifugal classifier (also referred to as a dry cyclone), a wet centrifugal classifier (also referred to as a wet cyclone), and the like.

[Slurry preparation process]
In the slurry preparation step, the opened inorganic fibers are mixed with a solvent, an inorganic binder, and an organic binder to prepare a slurry.

Although the order of mixing the inorganic binder and the organic binder is not particularly limited, it is preferable to first mix the inorganic fibers and the inorganic binder, and then add the organic binder after allowing the mixture to stand for a while. By first mixing the inorganic fibers and the inorganic binder, the inorganic binder will reliably adhere to the surface of the inorganic fibers, thereby increasing the friction between the inorganic fibers and improving the surface pressure. Furthermore, an aggregate obtained by aggregating an organic binder and an inorganic binder with an aggregating agent may be added to the slurry.

[Papermaking process (molding process)]
In the papermaking process, the slurry is poured into a molding machine with a mesh for filtration formed on the bottom, and then the solvent in the slurry is removed to obtain an inorganic fiber aggregate.
The shape of the molding machine at this time becomes the shape of a mat. In other words, it can be said that the papermaking process also serves as a forming process. Therefore, it is preferable to set the shape of the molding machine to the shape of the desired mat material.

The solvent removal treatment is not particularly limited as long as it can remove the solvent contained in the mat, but for example, the solvent can be removed by means such as compression, rotation, suction, and reduced pressure.

[Drying process]
In the drying step, the inorganic fiber aggregate is dried while being compressed using a method such as compression drying using a hot plate using a press dryer or the like.
Through the above steps, it is possible to obtain the mat material of the present invention in which an inorganic binder and/or an organic binder is attached to the surface of inorganic fibers.

[Exhaust gas purification device]
The exhaust gas purification device of the present invention includes an exhaust gas treatment body, a casing that accommodates the exhaust gas treatment body, and a mat member that is disposed between the exhaust gas treatment body and the casing and holds the exhaust gas treatment body. The purification device is characterized in that the mat material is the mat material of the present invention.

In the exhaust gas purification device of the present invention, since the mat material of the present invention is disposed between the exhaust gas treatment body and the casing, the exhaust gas treatment body can be stably held.

FIG. 12 is a cross-sectional view schematically showing an example of the exhaust gas purification device of the present invention.
As shown in FIG. 12, the exhaust gas purification device 200 includes a casing 220, an exhaust gas treatment body 230 housed in the casing 220, and a mat material 10 disposed between the exhaust gas treatment body 230 and the casing 220. There is. The mat material 10 is the mat material of the present invention.
The exhaust gas treatment body 230 is columnar in which a large number of cells 231 are arranged in parallel in the longitudinal direction with cell walls 232 in between. Note that an inlet pipe for introducing exhaust gas discharged from the internal combustion engine and an exhaust pipe for exhausting the exhaust gas that has passed through the exhaust gas purification device to the outside may be connected to the end of the casing 220, as necessary. become.
In the exhaust gas purification device 200 shown in FIG. 12, an exhaust gas filter (honeycomb filter) in which one of each cell is sealed with a sealing material 233 is used as the exhaust gas treatment body 230. A catalyst carrier that is not plugged with a sealing material may also be used.

As shown in FIG. 12, the exhaust gas discharged from the internal combustion engine and flowing into the exhaust gas purification device 200 (in FIG. 12, the exhaust gas is indicated by G and the flow of the exhaust gas is indicated by arrows) is transferred to an exhaust gas processing body (honeycomb filter) 230. The exhaust gas flows into one cell 231 opened at the exhaust gas inflow side end face 230a of the exhaust gas, and passes through the cell wall 232 that separates the cells 231. At this time, PM in the exhaust gas is collected by the cell wall 232, and the exhaust gas is purified. The purified exhaust gas flows out from another cell 231 opened at the exhaust gas outflow side end face 230b and is discharged to the outside.

Note that the exhaust gas inflow side end face 230a and the exhaust gas outflow side end face 230b, which are determined by the direction of the exhaust gas flowing into the exhaust gas purification device, are unrelated to the direction at the time of press-fitting.

[Manufacturing method of exhaust gas purification device]
The method for manufacturing an exhaust gas purification device of the present invention includes a press-fitting step of wrapping the mat material of the present invention around an exhaust gas treatment body and then press-fitting it into a casing by a hard stuffing method, a pre-calibration method, or a post-calibration method. It is characterized by

The hard stuffing method is a method in which a cylindrical casing having a predetermined inner diameter is prepared in advance, and an exhaust gas treatment body wrapped with a mat material is press-fitted into the casing.
The pre-calibration method is a method in which a cylindrical casing having a predetermined inner diameter is once reduced in diameter, and then an exhaust gas treatment body wrapped with a mat material is press-fitted into the casing.
The post-calibration method is a method in which an exhaust gas treatment body wrapped with a mat material is press-fitted into a cylindrical casing having a predetermined inner diameter, and then the diameter of the casing is reduced together with the exhaust gas treatment body and the mat material.

In all of the above methods, a large shearing force is applied to the mat material during press-fitting, so that the mat material is likely to shift and deform.
On the other hand, since the mat material of the present invention can suppress displacement and deformation of the mat material during press-fitting, it is particularly suitable for a method of manufacturing an exhaust gas purification device that includes these press-fitting steps.

In the method for manufacturing an exhaust gas purification device of the present invention, in the press-fitting step, it is preferable that the mat material is press-fitted into the casing with the first side surface on the upstream side and the second side surface on the downstream side.
In particular, when the length in the width direction of the non-sinking portion disposed on the first side surface side is longer than the length in the width direction of the non-sinking portion disposed on the second side surface side, the first side surface of the mat material is It is preferable to arrange the second side surface on the upstream side and the downstream side and press fit into the casing.

The following items are disclosed in this specification.

The present disclosure (1) is a mat material containing inorganic fibers and having a substantially rectangular shape in plan view,
The mat material has a first main surface and a second main surface facing each other in the thickness direction, a first end surface and a second end surface facing each other in the longitudinal direction, which is the winding direction, and It has a first side surface and a second side surface facing each other in the orthogonal width direction,
The first end surface includes a convex portion that protrudes toward the second end surface during winding, and non-protruding portions that are arranged on both sides of the convex portion in the width direction and do not protrude toward the second end surface. is formed,
The second end face includes a recess corresponding to the shape of the convex part of the first end face, and a shape of the non-protruding part of the first end face arranged on both sides of the recess in the width direction. A non-concave part corresponding to is formed,
A ratio [D/C] of the length [D] of the non-sinking portion in the width direction to the length [C] of the non-sinking portion in the longitudinal direction is 1.0 or more. It is a matte material.

The present disclosure (2) is the mat material according to the present disclosure (1), which is a needle mat.

The present disclosure (3) is a mat material having a plurality of intertwined points formed by needling on at least one of the front surface or the back surface, wherein the mat material has a 4 mm x 4 mm area in which the intertwined points are not present within a 25 mm x 25 mm area. The mat material according to (2) of the present disclosure, in which at least one of a first region, which is a region, and a second region, which is a 3 mm x 8 mm region in which the intertwining point does not exist, is arranged.

The present disclosure (4) is the mat material according to the present disclosure (2) or (3), wherein the inorganic fibers have an average fiber length of 1 to 150 mm.

The present disclosure (5) is the mat material according to the present disclosure (1), which is a paper-made mat.

The present disclosure (6) is the mat material according to the present disclosure (5), wherein the inorganic fibers have an average fiber length of 200 to 20,000 μm.

The present disclosure (7) is a mat material in any combination with any of the present disclosures (1) to (6), in which an inorganic binder is attached to the surface of the inorganic fibers.

The present disclosure (8) is a mat material in any combination with any of the present disclosures (1) to (6), in which an organic binder is attached to the surface of the inorganic fibers.

The present disclosure (9) is a mat material in any combination with any of the present disclosures (1) to (6), in which an inorganic binder and an organic binder are attached to the surface of the inorganic fibers.

The present disclosure (10) is a mat material in any combination with any of the present disclosures (1) to (9), which further contains a polymeric dispersant.

The present disclosure (11) is the mat material according to the present disclosure (9), wherein the inorganic binder and the organic binder are each attached to the surface of the inorganic fiber in a dispersed state.

The present disclosure (12) is the mat material according to the present disclosure (9), wherein an aggregate made of the inorganic binder and the organic binder is attached to the surface of the inorganic fiber.

The present disclosure (13) is the mat material according to the present disclosure (12), wherein at least a portion of the surface of the inorganic fiber is covered with a coating layer made of a mixture of the inorganic binder and the organic binder.

The present disclosure (14) is the mat material according to the present disclosure (13), wherein the coating layer is formed by a continuous scale-like mixture of the inorganic binder and the organic binder.

The present disclosure (15) is the mat material according to the present disclosure (13) or (14), wherein the coating layer has a multi-stage shape.

The present disclosure (16) provides any combination of any of the present disclosures (13) to (15), wherein a particulate mixture of the inorganic binder and the organic binder is attached to the surface of the coating layer. It is a matte material.

The present disclosure (17) provides the present disclosure, wherein a ratio [A/C] of the length [A] of the mat material in the longitudinal direction to the length [C] of the non-concave portion in the longitudinal direction is 10 or more. A mat material in any combination with any one of disclosures (1) to (16).

The present disclosure (18) is an exhaust gas purification device including a casing, an exhaust gas treatment body, and a mat material disposed between the casing and the exhaust gas treatment body,
The exhaust gas purification device is characterized in that the mat material is a mat material in any combination with any one of (1) to (17) of the present disclosure.

The present disclosure (19) provides a hard stuffing method, a pre-calibration method, or a post-calibration method after winding a mat material in any combination with any of the present disclosures (1) to (17) around an exhaust gas treatment body. This method of manufacturing an exhaust gas purification device is characterized by comprising a press-fitting step of press-fitting the exhaust gas purifying device into a casing by a compression method.

(Example)
Examples that more specifically disclose the present invention will be shown below. In the following examples, mats are manufactured by a needling method, but the present invention is not limited to these examples.

(Example 1)
(a) Spinning process The composition of the inorganic fiber after firing is calculated from a basic aluminum chloride aqueous solution prepared so that the Al content is 70 g/l and Al:Cl=1:1.8 (atomic ratio). Silica sol was blended so that the ratio of Al ₂ O ₃ :SiO ₂ =72:28 (weight ratio), and an appropriate amount of an organic polymer (polyvinyl alcohol) was added to prepare a mixed solution.
The obtained mixture was concentrated to obtain a spinning mixture, and this spinning mixture was spun by a blowing method to produce an inorganic fiber precursor having an average fiber diameter of 5.1 μm.

(b) Compression step The inorganic fiber precursor obtained in the above (a) spinning step was compressed to produce a continuous sheet-like product.

(c) Needle punching process The sheet-like material obtained in the above (b) compression process is subjected to needle punching process multiple times using a needle board on which needles are provided at a predetermined density to obtain a needle punched body. Created.
First, a needle board on which needles were attached at a predetermined density was prepared. Next, this needle board is placed above one surface of the sheet-like object, and a needle punching process is performed in which the needle board is moved up and down once along the thickness direction of the sheet-like object while moving the inorganic fiber precursor. This was repeated several times to produce a needle-punched body. At this time, the needle was penetrated until the barb formed at the tip of the needle completely penetrated the surface on the opposite side of the sheet-like material.

(d) Firing process The needle punched body obtained in the above (c) needle punching process is continuously fired at a maximum temperature of 1250°C, and is made of inorganic fibers containing alumina and silica in a ratio of 72 parts by weight: 28 parts by weight. A fired sheet-like product was produced. The average fiber diameter of the inorganic fibers was 5.1 μm, and the minimum fiber diameter was 3.2 μm. The fired sheet material thus obtained had a bulk density of 0.15 g/cm ³ and a basis weight of 1400 g/m ² . The density ρ of interlaced points is 9 pieces/cm ² , and within the 25 mm x 25 mm area, there are 10 first regions of 4 mm x 4 mm where no intersected points exist, and 3 mm x 8 mm where no intersected points exist. There were four second areas arranged.

(e) Cutting process The fired needle punched body was cut to produce a mat.
The dimensions of the mat are approximately rectangular in plan view, with a longitudinal length [A] of 348.0 mm, a width direction length [B] of 93.5 mm, and a convex length [C] of 20.0 mm. , the width of the non-concave portion [D ₁ and D ₂ ] is 31 mm, the width of the convex portion [E] is 31.5 mm, and the widthwise center of the concave portion [E _C ] and the widthwise center of the mat [ B _C ] overlapped.

(f) Impregnation Step (f-1) Organic Binder Mixture Preparation Step An organic binder mixture having a solid content concentration of 2.0 wt% was prepared by diluting acrylate latex as an organic binder with water.

(f-2) Inorganic binder mixed liquid preparation process By diluting alumina, which is an inorganic binder, with water, adding a polymeric dispersant, and stirring thoroughly, the solid content concentration of inorganic particles is 2.0 wt%. An inorganic binder mixture containing the above-mentioned polymeric dispersant at a concentration of 1000 ppm was prepared.

(f-3) Binder mixture preparation step The organic binder obtained in the above (f-1) organic binder mixture preparation step is mixed with the inorganic binder mixture obtained in the above (f-2) Inorganic binder mixture preparation step. The liquids were added at a weight ratio of 1:1 and thoroughly stirred, so that the organic binder had a solid content concentration of 1.0 wt%, the inorganic binder had a solid content concentration of 1.0 wt%, and the concentration of the polymeric dispersant was 1.0 wt%. A binder mixture solution having a concentration of 500 ppm was prepared.

(f-4) Contact step The binder mixture obtained in the above (f-3) binder mixture preparation step was brought into contact with the mat obtained in the (e) cutting step by a curtain coating method.
(f-5) Dehydration step The mat obtained in the above (f-4) contact step and to which the binder mixture has been applied is dehydrated by suction using a dehydrator, so that the binder mixture is reduced to 100 parts by weight of inorganic fibers. It was prepared so that 100 parts by weight was added.

(f-6) Drying process The mat that had undergone the above (f-5) dehydration process was dried in a dryer to produce a mat material according to Example 1.

(Examples 2 to 6 and Comparative Examples 1 to 3)
(e) Mat materials according to Examples 2 to 6 and Comparative Examples 1 to 3 were produced in the same manner as in Example 1, except that the shape to be cut in the cutting process was changed to meet the conditions in Table 1. .
Note that [D ₁ ] indicates the width of the non-sinking portion on the first side surface side, and [D ₂ ] indicates the width of the non-sinking portion on the second side surface side, respectively.

(Press-fit test)
The mat materials according to Examples 1 to 3 and Comparative Examples 1 to 2 were wound around an exhaust gas treatment body having a diameter of 103 mm and a length of 105 mm, and the wrapped body had a diameter of 115 mm and a taper angle of 4.5° and an aperture diameter of 110.7 mm. Using a press-fitting jig, the mat material was press-fitted into a stainless steel casing having an inner diameter of 110.8 mm at a speed of 500 mm/min so that the first side face was on the upstream side and the second side face was on the downstream side.
When wrapping the mat material around the exhaust gas treatment body, record the length [L ₀ ] from the upstream end surface of the exhaust gas treatment body to the upstream end surface (first side surface) of the mat material, and after press-fitting, Again, measure the length [L ₁ ] from the upstream end surface of the exhaust gas treatment body to the upstream end surface (first side surface) of the mat material, and calculate the difference [ΔL] as the amount of deformation (amount of deviation) of the mat material. It was evaluated using the following criteria.
Note that the mat materials according to Examples 4 to 6 and Comparative Example 3 were made by wrapping a wound body with a diameter of 141 mm around an exhaust gas treatment body with a diameter of 129 mm and a length of 105 mm, with a taper angle of 4.5° and an aperture diameter of 145. Using a 3 mm press-fit jig, the mat material was press-fitted into a stainless steel casing with an inner diameter of 145.4 mm at a speed of 500 mm/min so that the first side surface was on the upstream side and the second side surface was on the downstream side.
[Evaluation criteria]
◎: Deformation amount (shift amount) is 6 mm or less, and deformation of the mat material is particularly suppressed.
Good: The amount of deformation (amount of deviation) is more than 6 mm and less than 8 mm, and deformation of the mat material is sufficiently suppressed.
×: The amount of deformation (amount of deviation) exceeds 8 mm, and the deformation of the mat material is not sufficiently suppressed.

As shown in Table 1, it was confirmed that all of the mat materials according to the present invention can suppress deformation and displacement of the mat materials during press-fitting. Furthermore, from a comparison between Examples 1 to 5 and Example 6, the ratio [A/C] of the length [A] of the mat material in the longitudinal direction to the length [C] of the non-concave part in the longitudinal direction was set to 10. It has been found that by doing so, deformation and displacement of the mat material during press-fitting can be particularly suppressed.

1a, 1b Test piece 10 Mat material 11 First main surface 12 Second main surface 13 First end surface

13a Convex portions

13b, 13c Non-protruding portion 14 Second end surface 14a Recessed

portions

14b, 14c Non-concave portion 15 First side surface 16 Second Side surface 115 Intertwining point 117 First region 118 Second region 120 Inorganic fiber 130 Covering layer 140 Particulate mixture 170 Shear failure load test device 171 Left jig 172 Right jig 173 Stainless steel plate 174 Projection member 200 Exhaust gas purification device 220 Casing 230 Exhaust gas treatment body 230a Exhaust gas inflow end face 230b Exhaust gas outflow end face 231 Cell 232 Cell wall 233 Sealing material 250 Wrapping body

Claims

A mat material containing inorganic fibers and having a substantially rectangular shape in plan view,
The mat material has a first main surface and a second main surface facing each other in the thickness direction, a first end surface and a second end surface facing each other in the longitudinal direction, which is the winding direction, and It has a first side surface and a second side surface facing each other in the orthogonal width direction,
The first end surface includes a convex portion that protrudes toward the second end surface during winding, and non-protruding portions that are arranged on both sides of the convex portion in the width direction and do not protrude toward the second end surface. is formed,
The second end face includes a recess corresponding to the shape of the convex part of the first end face, and a shape of the non-protruding part of the first end face arranged on both sides of the recess in the width direction. A non-concave part corresponding to is formed,
A ratio [D/C] of the length [D] of the non-sinking portion in the width direction to the length [C] of the non-sinking portion in the longitudinal direction is 1.0 or more. mat material.
The mat material according to claim 1, which is a needle mat.
A mat material having a plurality of intertwined points formed by needling on at least one of the front surface or the back surface, the first mat material having a 4 mm x 4 mm area in which no intertwined points are present within a 25 mm x 25 mm area. The mat material according to claim 2, wherein at least one of the area and the second area, which is a 3 mm x 8 mm area where the intertwining point does not exist, is arranged.
The mat material according to claim 2 or 3, wherein the inorganic fibers have an average fiber length of 1 to 150 mm.
The mat material according to claim 1, which is a paper-made mat.
The mat material according to claim 5, wherein the inorganic fibers have an average fiber length of 200 to 20,000 μm.
The mat material according to any one of claims 1 to 6, wherein an inorganic binder is attached to the surface of the inorganic fiber.
The mat material according to any one of claims 1 to 6, wherein an organic binder is attached to the surface of the inorganic fiber.
The mat material according to any one of claims 1 to 6, wherein an inorganic binder and an organic binder are attached to the surface of the inorganic fiber.
The mat material according to any one of claims 1 to 9, further containing a polymeric dispersant.
The mat material according to claim 9, wherein the inorganic binder and the organic binder are attached to the surface of the inorganic fibers in a dispersed state.
The mat material according to claim 9, wherein an aggregate made of the inorganic binder and the organic binder is attached to the surface of the inorganic fiber.
The mat material according to claim 12, wherein at least a part of the surface of the inorganic fiber is covered with a coating layer made of a mixture of the inorganic binder and the organic binder.
The mat material according to claim 13, wherein the coating layer is formed by a continuous scale-like mixture of the inorganic binder and the organic binder.
The mat material according to claim 13 or 14, wherein the covering layer has a multi-stage shape.
The mat material according to any one of claims 13 to 15, wherein a particulate mixture of the inorganic binder and the organic binder is attached to the surface of the coating layer.
Any one of claims 1 to 16, wherein the ratio [A/C] of the length [A] of the mat material in the longitudinal direction to the length [C] of the non-concave portion in the longitudinal direction is 10 or more. Mat material listed.
An exhaust gas purification device comprising a casing, an exhaust gas treatment body, and a mat material disposed between the casing and the exhaust gas treatment body,
An exhaust gas purification device characterized in that the mat material is the mat material according to any one of claims 1 to 17.
A press-fitting step of wrapping the mat material according to any one of claims 1 to 17 around an exhaust gas treatment body and then press-fitting it into a casing by a hard stuffing method, a pre-calibration method, or a post-calibration method, A method for manufacturing an exhaust gas purification device, characterized in that: