Holding member for exhaust gas purification device and exhaust gas purification device

Abstract

This holding member for an exhaust gas purification device is provided with an inorganic fiber molded body, constituting inorganic fibers and containing no binder. The inorganic fiber molded body has needle marks extending in the thickness direction, the needle marks have warp threads comprising the inorganic fibers extending in the thickness direction, the needle mark density is 8.0-18.0 marks / cm2, and the number of effective warp threads is 2.8-6.0 threads / cm2. When the following peeling method is carried out, the effective warp threads represent warp threads having a diameter of 100 μm or more and a projection length of 2 mm or more, among all the warp threads projecting from one peeling surface and the other peeling surface, in the range of 50 mm x 50 mm.

Description

Grip Material for Exhaust Gas Purification Device and Exhaust Gas Purification Device

[0001] The present disclosure relates to a grip material for an exhaust gas purification device and an exhaust gas purification device.

[0002] An inorganic fiber molded body obtained by molding inorganic fibers typified by ceramic fibers into a mat shape is used in products exposed to high-temperature states such as industrial heat insulating materials, refractory materials, packing materials, etc. In recent years, the above inorganic fiber molded body is also used as a grip material (hereinafter also referred to as "grip material") for an exhaust gas purification device of an automobile.

[0003] Patent Document 1 discloses a grip sealing material disposed between a catalyst carrier in an exhaust gas purification catalyst converter and a shell covering the outside thereof. In this grip sealing material, a binder such as an organic binder is attached to a mat-like object formed by arranging inorganic fibers in a mat shape.

[0004] Also, in the manufacture of an exhaust gas purification device for an automobile, it is known to dispose an assembly (hereinafter also referred to as "assembly") in which a grip material is wound around a catalyst carrier into a casing by press-fitting.

[0005] Patent No. 4042305

[0006] In the grip sealing material described in Patent Document 1, the organic binder dissolves during the first combustion. At this time, since the organic binder functions as a lubricant, the surface pressure of the grip sealing material may decrease. Therefore, in the grip sealing material described in Patent Document 1, there is a risk that the catalyst carrier may fall off during the first combustion.

[0007] Also, when the assembly is press-fitted into the casing, it is known that the grip material is deformed. When this deformation amount increases, the effective area of the grip material contributing to the force for gripping the catalyst carrier decreases. As a result, there is a risk that the catalyst carrier may fall off.

[0008] Furthermore, when the grip material is used for a long period of time, it is known that the surface pressure of the grip material contributing to the force for gripping the catalyst carrier decreases. Therefore, after long-term use, there is a risk that the catalyst carrier may fall off.

[0009] From the above, one example of the object of the present invention is to provide a gripping material for an exhaust gas purification device and an exhaust gas purification device that can suppress the detachment of the catalyst support from the casing throughout the entire lifecycle, from immediately after the start of use to after long-term use. Other objects of the present invention will become clear from the description herein.

[0010] This disclosure includes, for example, the following subjects:

[0011] Item 1. A gripping material for an exhaust gas purification device, comprising an inorganic fiber molded body composed of inorganic fibers and not containing a binder, wherein the inorganic fiber molded body has needle marks extending in the thickness direction, and the needle marks contain warp threads made of the inorganic fibers extending in the thickness direction, with a needle mark density of 8.0 to 18.0 marks / cm². ２ The number of effective warp threads is 2.8 to 6.0 threads / cm. ２ The gripping material for exhaust gas purification equipment is such that, when the following peeling method is performed, the effective warp threads represent all warp threads that protrude from one peeled surface and the other peeled surface within a 50 mm x 50 mm area, and have a diameter of 100 μm or more and a protruding length of 2 mm or more. <Peeling Method> A test piece with a width of 50 mm and a length of 150 mm is cut out from an inorganic fiber molded body. Next, a 30 mm deep cut is made in the center of the thickness of one end face of this test piece, and after supporting both ends formed by the cut in a gripping jig, it is set in a tensile testing machine. At a speed of 500 mm / min, both ends of the test piece are pulled in opposite thickness directions to tear it in two. Item 2. The total volume of the effective warp threads is 6.5 to 10.0 mm ３ / cm ２ A gripping material for an exhaust gas purification device as described in item 1. Item 3. Basis weight of 1000 to 2000 g / m² ２ A gripping material for an exhaust gas purification device as described in item 1 or 2. Item 4. The average volume per effective warp thread is 1.5 to 4.0 mm ３ / A gripping material for an exhaust gas purification device as described in any one of paragraphs 1 to 3. Paragraph 5. A gripping material for an exhaust gas purification device as described in any one of paragraphs 1 to 4, wherein the residual surface pressure after a high-temperature cycle is 30 kPa or more. Paragraph 6. An exhaust gas purification device comprising: a catalyst support; a casing covering the outside of the catalyst support; and a gripping material for an exhaust gas purification device as described in any one of paragraphs 1 to 5, disposed between the catalyst support and the casing.

[0012] According to this disclosure, a gripping material for an exhaust gas purification device and an exhaust gas purification device are provided that can suppress the detachment of the catalyst support from the casing throughout the entire lifecycle, from immediately after the start of use to after long-term use.

[0013] (A)-(D) These are explanatory diagrams showing each step in press-fitting the catalyst support body, around which the gripping material is wound, into the casing. These are explanatory diagrams of the cut test piece. These are explanatory diagrams of the peeling method. (A) This is a partially approximate cross-sectional view showing the force applied to the gripping material when the assembly in Figure 1 is press-fitted into the casing. (B) This is a partially approximate cross-sectional view showing the deformation of the gripping material when an assembly with a gripping material having a small number of effective warp threads is press-fitted into the casing. (C) This is a partially approximate cross-sectional view showing the deformation of the gripping material when an assembly with a gripping material having a large number of effective warp threads is press-fitted into the casing. (A) This is a partially side cross-sectional view of the assembly before press-fitting. (B) This is a partially side cross-sectional view of the assembly in a state where the gripping material 1 has deformed relative to the catalyst support body 2 due to press-fitting.

[0014] In this specification, nouns without numerical limitations include both singular and plural forms, unless otherwise explicitly stated herein or the context clearly contradicts this.

[0015] In this specification, "to provide" is a concept that also includes "to consist substantially only of" and "to consist only of."

[0016] In the numerical ranges described stepwise in this specification, the upper or lower limit of a numerical range in one step can be arbitrarily combined with the upper or lower limit of a numerical range in another step. Furthermore, in the numerical ranges described in this specification, the upper or lower limit of a numerical range may be replaced with values ​​shown in the examples or values ​​that can be uniquely derived from the examples. Moreover, in this specification, numbers connected by "~" mean a numerical range that includes the numbers before and after "~" as the lower and upper limits.

[0017] The embodiments included in this disclosure will be described further below. The embodiments described below are examples of typical embodiments of this disclosure and do not limit the scope of the invention.

[0018] [Gripping material for exhaust gas purification device] As shown in Figures 1(A)-(D), the gripping material 1 for the exhaust gas purification device of the present disclosure (hereinafter also referred to as "gripping material 1") is housed in a metal casing 6 in an assembly 3 in which the gripping material 1 is wound around the catalyst support 2. The gripping material 1 is positioned between the catalyst support 2 and the casing 6. The gripping material 1 grips the catalyst support 2 as a cushioning material for the catalyst support 2. The gripping material 1 is obtained by subjecting an inorganic fiber molded body of the present disclosure to die-cutting or the like. As shown in Figure 1(A), the gripping material 1 comprises substantially straight long sides 1g and 1h of substantially the same length, and short sides 1j and 1k that connect the ends of the long sides 1g and 1h, respectively. The short side 1j comprises straight portions on both sides and a protruding portion 1m defined by three substantially straight sides that are sandwiched between the straight portions and protrude outward from the straight portions. The shorter side 1k comprises straight sections on both sides and a recess 1n defined by three substantially straight sides that are sandwiched between the straight sections and protrude inward from the straight sections.

[0019] In this disclosure, the properties of the gripping material 1 are the same as those of the inorganic fiber molded article. Therefore, when describing the properties of the gripping material 1 below, the properties of the inorganic fiber molded article may be used.

[0020] The gripping material 1 for the exhaust gas purification device of this disclosure comprises an inorganic fiber molded body composed of inorganic fibers and does not contain a binder. The inorganic fiber molded body has needle marks extending in the thickness direction, and the needle marks contain warp threads made of the inorganic fibers extending in the thickness direction, with a needle mark density of 8.0 to 18.0 marks / cm². ２ The number of effective warp threads is 2.8 to 6.0 threads / cm. ２ The effective warp threads refer to all warp threads that protrude from one peeled surface and the other peeled surface within a 50 mm x 50 mm area when the peeling method described below is performed, and which have a diameter of 100 μm or more and a protruding length of 2 mm or more.

[0021] <Method of peeling> A test piece 10 with a width of 50 mm and a length of 150 mm is cut out from the inorganic fiber molded body. Next, as shown in Figure 2, a cut 30 mm deep is made in the center of the thickness of one end face 10e of this test piece 1. Next, as shown in Figure 3, both ends formed by the cut are grasped and supported in a jig 12, and then set in a tensile testing machine. At a speed of 500 mm / min, both ends are pulled in opposite thickness directions to tear it into two pieces.

[0022] <Inorganic Fiber Molded Article> In one aspect of this disclosure, the inorganic fiber molded article is obtained by firing a molded article of inorganic fiber precursors. In one aspect of this disclosure, the molded article of inorganic fiber precursors is obtained by needling a laminated sheet. In one aspect of this disclosure, the laminated sheet is obtained by laminating thin sheets. In one aspect of this disclosure, the thin sheet is obtained by collecting inorganic fiber precursors. In one aspect of this disclosure, the inorganic fiber precursors are obtained by spinning a spinning solution using a blowing method. The inorganic fiber molded article is in the form of a mat having a predetermined thickness. The surface perpendicular to the thickness direction of the inorganic fiber molded article may hereafter be referred to as the mat surface. Also, the side surface (surface in the thickness direction) perpendicular to the mat surface of the inorganic fiber molded article may hereafter be referred to as the end surface.

[0023] <Inorganic Fibers> There are no particular restrictions on the inorganic fibers that make up the inorganic fiber molded body of the present disclosure, and examples include silica, alumina / silica, zirconia, spinel, titania, etc. that contain these, either alone or as composite fibers. Particularly preferred are alumina / silica-based fibers, especially crystalline alumina / silica-based fibers. The composition ratio of alumina / silica in the alumina / silica-based fibers is preferably in the range of 60 to 95 / 40 to 5 by weight ratio, more preferably in the range of 70 to 84 / 30 to 16, and particularly preferably in the range of 70 to 76 / 30 to 24.

[0024] Also, the inorganic fibers are preferably short fibers. There are no particular restrictions on the fiber length of the inorganic fibers, but preferably it is 1 mm or more and 1000 mm or less, more preferably 30 mm or more and 800 mm or less. The average fiber diameter of the inorganic fibers is preferably 3 to 10 μm, and more preferably 5 to 8 μm. If the average fiber diameter of the inorganic fibers is 8 μm or less, it is preferable because the inorganic fiber molded body has an appropriate repulsive force. Also, if the average fiber diameter of the inorganic fibers is 5 μm or more, it is preferable because the amount of dust floating in the air can be suppressed.

[0025] <Basis Weight and Thickness of Inorganic Fiber Molded Body> The basis weight (mass per unit area) of the inorganic fiber molded body of the present disclosure is appropriately determined according to the application, but preferably it is 1000 g / m ２ or more, more preferably 1200 g / m ２ or more. Also, the basis weight of the inorganic fiber molded body of the present disclosure is 1000 to 2000 g / m ２ in terms of obtaining the gripping material 1 that can suppress the dropout of the catalyst carrier 2 from the casing 6 throughout the entire life cycle, and preferably it is 1000 to 1800 g / m ２ more preferably, and 1200 to 1800 g / m ２ is even more preferable.

[0026] The thickness of the inorganic fiber molded body of the present disclosure is preferably 3 mm or more, more preferably 5 mm or more. Also, the thickness of the inorganic fiber molded body of the present disclosure is preferably 40 mm or less, more preferably 30 mm or less, even more preferably 25 mm or less, and particularly preferably 23 mm or less.

[0027] For example, Figures 1(A)-(D) show the steps for press-fitting the assembly 3 into the casing 6. Figure 1(A) shows the step of preparing the gripping material 1 and the catalyst support 2. Figure 1(B) shows the step of preparing the assembly 3 by winding the gripping material 1 around the catalyst support 2 and fixing the gripping material 1 with fixing tape 4 or the like. Figure 1(C) shows the step of press-fitting the assembly 3 into the casing 6 using a jig 7. Figure 1(D) shows the step of completing the exhaust gas purification device 8, which includes the catalyst support 2, the casing 6 that covers the outside of the catalyst support 2, and the gripping material 1 positioned between the catalyst support 2 and the casing 6.

[0028] The larger the basis weight and thickness of the inorganic fiber molded body of this disclosure, the greater the deformation of the gripping member 1 tends to be when the assembly 3 is pressed into place. On the other hand, in order to avoid the catalyst support 2 falling off, it is preferable that the deformation of the gripping member 1 be small when the assembly 3 is pressed into place in the casing 6.

[0029] The basis weight and thickness of the inorganic fiber molded article can be set to the above range by adjusting the amount of fiber per unit area when the aggregate of inorganic fiber precursors constituting the inorganic fiber molded article (hereinafter also referred to as "thin sheet") is laminated using a folding device. Furthermore, the inorganic fiber molded article of this disclosure may be a single structure or a structure in which multiple inorganic fiber molded articles are bonded together, but a single structure is preferred in terms of handling properties and peel strength at the adhesive interface.

[0030] <Needle Mark Density> <Method for Measuring Needle Mark Density> In one aspect of this disclosure, the needle mark density of an inorganic fiber molded body is measured per unit area (1 cm²) of the mat surface of the inorganic fiber molded body (a molded body of inorganic fiber precursors that has been fired). ２ This refers to the number of needle marks per area.

[0031] When visible light is shone on the matte surface of an inorganic fiber molded body subjected to the exfoliation method described above, the amount of transmitted light at the needle marks is greater than the amount of transmitted light in areas other than the needle marks, so the transmitted light is observed as light spots on the exfoliated surface. The number of light spots and warp threads due to transmission to this exfoliated surface is counted, and the needle mark density is determined by dividing the sum of the number of light spots and warp threads by the area.

[0032] Specifically, visible light is shone on one side of the inorganic fiber molded body, and the number of light spots and warp threads transmitted to this delamination surface is counted. The needle mark density is then determined by dividing the sum of the number of light spots and warp threads by the area.

[0033] ≪Preferred range of needle mark density≫ In this disclosure, the unit area (1 cm²) of the mat surface of the inorganic fiber molded body. ２ The needle mark density, which is the number of needle marks per square centimeter, is 8.0 to 18.0 marks / cm² as an average value across the entire mat surface. ２ The needle mark density is such that there is a trade-off between the ease with which the gripping material 1 deforms during press-fitting and the height of the remaining surface pressure after high-temperature cycling of the gripping material 1. ２ If the value is less than 18.0 needle marks / cm², the deformation of gripping material 1 during press-fitting will be greater. ２ If it exceeds this value, the residual surface pressure of the gripping material 1 after the high-temperature cycle decreases. Therefore, 8.0 to 18.0 pieces / cm ２ An inorganic fiber molded body that satisfies the needle mark density can achieve both resistance to deformation during press-fitting of the gripping material 1 and high residual surface pressure after high-temperature cycling. Both resistance to deformation during press-fitting of the gripping material 1 and high residual surface pressure after high-temperature cycling contribute to suppressing the detachment of the catalyst support 2 from the casing 6, resulting in a needle mark density of 8.0 to 18.0 pieces / cm ２ By satisfying the needle mark density, the detachment of the catalyst support 2 from the casing 6 can be suppressed throughout the entire lifecycle.

[0034] <Warp Threads> The inorganic fiber molded article of this disclosure has needle marks formed by a needling process. When a needling process is performed in which a barbed needle is inserted into and removed from a laminated sheet, at least some of the fibers are extended in the substantially thickness direction by the needle at the locations where the needle has been inserted and removed. Bundles of inorganic fibers formed in the substantially thickness direction inside the inorganic fiber molded article by this needling process are called warp threads.

[0035] <Effective Warp Threads> In this disclosure, when the above peeling method is performed, among all the warp threads F (Figure 3) that protrude from both peeling surfaces (one peeling surface 10a and the other peeling surface 10b) per unit area (50 mm x 50 mm), the warp threads F with a diameter of 100 μm or more and a protruding length of 2 mm or more are defined as effective warp threads. The unit area (50 mm x 50 mm) for measuring each value related to the warp threads F is any region of the test piece 10 (150 mm x 50 mm), avoiding the area where a 30 mm deep cut is made in the center of the thickness.

[0036] The effective warp threads have a diameter and length that act to adjust the resistance to deformation during press-fitting of the gripping material 1 and the residual surface pressure after high-temperature cycling.

[0037] <Number of effective warp threads> In the inorganic fiber molded article of this disclosure, the number of effective warp threads is 2.8 to 6.0 threads / cm ２ That is the case.

[0038] The number of effective warp threads is 2.8 threads / cm ２ If the number is less than 6.0 warp threads / cm, the gripping material 1 is prone to deformation during press-fitting. ２ If it exceeds this, the residual surface pressure of the gripping material 1 after the high-temperature cycle decreases. In one aspect of this disclosure, the number of effective warp threads is 2.8 to 5.0 threads / cm ２ Within this range, it is possible to achieve both resistance to deformation during press-fitting of the gripping material 1 and high residual surface pressure after high-temperature cycling.

[0039] Referring to Figure 4(A), similar to Figures 1(B) to (D), a gripping material 1 made of an inorganic fiber molded body is wound around a catalyst support 2, and multiple warp threads extend from the inorganic fiber molded body of the gripping material 1. When the assembly 3 is pressed into the casing (reference numeral 6 in Figure 1(C)), the gripping material 1 is subjected to shear stress as indicated by the arrows in Figure 4(A). As shown in Figure 4(B), when an inorganic fiber molded body with a small number of effective warp threads 1t is used, the gripping material 1 is weak against shear stress and is easily deformed during press-fitting. However, when the number of effective warp threads 1t is small, the restraining force that maintains the thickness of the inorganic fiber molded body is weak, so the surface pressure applied from the gripping material 1 to the catalyst support 2 is relatively high. On the other hand, as shown in Figure 4(C), when an inorganic fiber molded body with a large number of effective warp threads 1t is used, the gripping material 1 is strong against shear stress and is less likely to deform during press-fitting. However, when the number of effective warp threads 1t is large, the restraining force that maintains the thickness of the inorganic fiber molded body is strong, so the surface pressure applied to the catalyst support 2 from the gripping material 1 is relatively low. The gripping material 1 of this disclosure balances the trade-off between strength against shear stress (resistance to deformation during press-fitting) and the high residual surface pressure applied to the catalyst support 2 after high-temperature cycling, thereby suppressing the detachment of the catalyst support 2 from the casing 6 throughout the entire lifecycle.

[0040] <Total volume V of effective warp threads> After performing the above peeling method, the number (number) N, diameter (thickness) D, and length (length of protrusion from the peeling surface 10a or 10b) L of the effective warp threads protruding from the peeling surfaces 10a and 10b are measured using a digital microscope. The measurement magnification of the digital microscope is preferably 10 to 20 times. The length L is the length of the portion protruding from the peeling surface 10a or 10b, and the portion with a diameter of 100 μm or more is measured. The diameter D is the value measured at approximately the midpoint in the length direction of the portion protruding from the peeling surface 10a or 10b.

[0041] In this 50 mm x 50 mm area, the total volume V of the effective warp threads is equal to the volume of each of the N effective warp threads (πD). ２ This is the value obtained by calculating L / 4 and summing them up.

[0042] In the inorganic fiber molded article of this disclosure, the total volume (sum of volumes) V of the effective warp threads is 6.5 to 10.0 mm ３ / cm ２ This total volume range is preferable in that it suppresses deformation during press-fitting and provides a gripping material 1 with high residual surface pressure after high-temperature cycling. In one embodiment of the present disclosure, the total volume (sum of volumes) V of the effective warp threads is 7.0 to 10.0 mm ３ / cm ２ Within this range, it is possible to achieve both resistance to deformation during press-fitting of the gripping material 1 and high residual surface pressure after high-temperature cycling.

[0043] When the number of effective warp threads is constant, the smaller the total volume V of effective warp threads in the inorganic fiber molded body, the thinner the effective warp threads become, and the inorganic fiber molded body is weaker against shear stress. For this reason, the gripping material 1 is easily deformed during press-fitting, but the surface pressure applied from the gripping material 1 becomes relatively high. On the other hand, the larger the total volume V of effective warp threads in the inorganic fiber molded body, the thicker the effective warp threads become, and the inorganic fiber molded body is stronger against shear stress. For this reason, the gripping material 1 is less likely to deform during press-fitting, but the surface pressure applied from the gripping material 1 becomes relatively low. Thus, the total volume V of effective warp threads in the inorganic fiber molded body of this disclosure also contributes to achieving both the strength of the gripping material 1 against shear stress (resistance to deformation during press-fitting) and the high residual surface pressure applied to the catalyst support 2 after high-temperature cycling.

[0044] <Multiple Needle Rate> In this disclosure, applying a needlering process to a location where a needle mark has already been formed is defined as multiple needlering, and the needle mark formed in this way is defined as a multiple needle mark. The multiple needle rate (i.e., the number of multiple needle marks) can be adjusted in the needlering process, for example, by changing the transport speed of the laminated sheet. Multiple needlering is one example of a means to thicken the warp threads. The multiple needle rate can be determined by the following formula 1.

[0045] The measured needle mark density is the measured value obtained by the needle mark density measurement method described above. The theoretical needle mark density is the theoretical value of the needle mark density calculated assuming that there are no multiple needle marks.

[0046] In multi-needle marks, the warp threads tend to be thicker compared to single-needle marks. Therefore, the volume of the warp threads in multi-needle marks tends to be larger. In other words, by forming multi-needle marks, it is possible to increase the total volume V of the effective warp threads without increasing the needle mark density. As a result, compared to increasing the needle mark density, it is possible to form stronger warp threads (i.e., stronger restraining force to maintain the thickness of the inorganic fiber molded body) without excessively reducing the residual surface pressure after high-temperature cycling. As described above, the multi-needle processing also contributes to achieving both the strength of the gripping material 1 against shear stress (resistance to deformation during press-fitting) and the high residual surface pressure applied to the catalyst support 2 after high-temperature cycling.

[0047] <Average volume of effective warp threads per needle mark> The number of needle marks n in the 50 mm x 50 mm area described above is measured using the measurement method described above. By dividing the total volume V obtained by performing the peeling method by n, the average volume of effective warp threads per needle mark (hereinafter sometimes referred to as "average volume of effective warp threads per needle mark") can be obtained.

[0048] In other words, the average volume of effective warp threads per needle mark is the value V / n obtained by dividing the sum of the volumes of all effective warp threads (total volume) V present on both peeling surfaces (one peeling surface 1a and the other peeling surface 1b) per unit area (50 mm x 50 mm) when the peeling method is performed by the number of needle marks n per unit area. The larger the average volume of effective warp threads per needle mark V / n, the more effectively the needling process is performed, and the stronger the effective warp threads (i.e., the stronger the restraining force that maintains the thickness of the inorganic fiber molded body) are formed. The average volume of effective warp threads per needle mark of the inorganic fiber molded body of this disclosure also contributes to achieving both the strength of the gripping material 1 against shear stress (resistance to deformation during press-fitting) and the high residual surface pressure applied to the catalyst support 2 after high-temperature cycling.

[0049] The average volume of effective warp threads per needle mark in the inorganic fiber molded body is preferably 0.40 mm². ３ The above, and more preferably, 0.45 mm３ The above is the case. The average volume of effective warp threads per needle mark in the inorganic fiber molded body is preferably 1.0 mm ３ More preferably, 0.95 mm ３ The following applies:

[0050] <Average volume per effective warp thread> By dividing the total volume V by the number of effective warp threads N, the average volume per effective warp thread (hereinafter sometimes referred to as "average volume per effective warp thread") can be obtained.

[0051] In other words, the average volume per effective warp is the value V / N obtained by dividing the sum of the volumes (total volume) V of all effective warp present on both peeling surfaces (one peeling surface 1a and the other peeling surface 1b) per unit area (50 mm x 50 mm) when the peeling method is performed by the number of effective warp in that unit area N. The larger the average volume V / N per effective warp in the inorganic fiber molded body, the more effectively the needling process is performed, and the stronger the effective warp (i.e., the stronger the restraining force that maintains the thickness of the inorganic fiber molded body) is formed. The average volume per effective warp in the inorganic fiber molded body of this disclosure also contributes to achieving both the strength of the gripping material 1 against shear stress (resistance to deformation during press-fitting) and the high residual surface pressure applied to the catalyst support 2 after high-temperature cycling.

[0052] The average volume per effective warp thread of the inorganic fiber molded body is preferably 1.0 mm². ３ The above, and more preferably 1.5 mm ３ That concludes the explanation. The average volume of effective warp threads per effective warp thread in the inorganic fiber molded article is preferably 4.0 mm ３ More preferably, 3.5 mm ３ The following applies:

[0053] <Residual surface pressure after high-temperature cycling> In the inorganic fiber molded article of this disclosure, the surface pressure after high-temperature cycling can be determined by the following measurement test. The inorganic fiber molded article has a GBD (bulk density) of 0.30 g / cm³. ３ After compressing for 30 minutes, the upper and lower plates were heated to 600°C, and upon release, the GBD was 0.27 g / cm³. ３ Compressed GBD = 0.30 g / cm²３ The process of opening and compressing is repeated 1000 times. During the first opening, the GBD (GBD = 0.27 g / cm²) is used. ３ The surface pressure value at the 1000th opening (GBD = 0.27 g / cm²) and the value at the 1000th opening (GBD = 0.27 g / cm²) ３ The surface pressure value of the device is measured. At this time, the surface pressure value (kPa) at the 1000th opening is defined as the residual surface pressure (also called residual surface pressure) after the high-temperature cycle.

[0054] The inorganic fiber molded article of this disclosure can maintain excellent gripping force of the catalyst support over a long period of time if the residual surface pressure after high-temperature cycling is high. For this reason, the inorganic fiber molded article of this disclosure preferably has a residual surface pressure of 30 kPa or more after high-temperature cycling, more preferably 33 kPa or more, and particularly preferably 35 kPa or more. Furthermore, while a higher residual surface pressure after high-temperature cycling is advantageous in that it can maintain gripping force over a long period of time, the amount of deformation during press-fitting generally tends to increase. From the viewpoint of suppressing the amount of deformation during press-fitting, the residual surface pressure of the inorganic fiber molded article of this disclosure after high-temperature cycling is preferably 50 kPa or less, more preferably 45 kPa or less, and particularly preferably 40 kPa or less.

[0055] [Method for Manufacturing the Gripping Material] The gripping material 1 of this disclosure can be manufactured by a method including a spinning process, a needling process, a firing process, and a punching process, as described later. However, the gripping material 1 of this disclosure may be manufactured by other methods.

[0056] The following describes an example of a method for manufacturing this gripping material, using a method for manufacturing an alumina / silica fiber molded body as an example. However, the gripping material of this disclosure is not limited to comprising an alumina / silica fiber molded body, and as mentioned above, may comprise a molded body made of silica, zirconia, spinel, titania, or composite fibers thereof.

[0057] <Spinning Process> In the spinning process, a spinning solution containing basic aluminum chloride, a silicon compound, an organic polymer as a thickener, and water is spun by the blowing method to obtain a laminated sheet of alumina / silica fiber precursor.

[0058] <<Preparation of spinning solution>> Basic aluminum chloride; Al(OH) ３－ｘ Cl ｘ This can be prepared, for example, by dissolving metallic aluminum in hydrochloric acid or an aqueous solution of aluminum chloride. The value of x in the above chemical formula is usually 0.45 to 0.54, preferably 0.5 to 0.53. Silica sol is preferably used as the silicon compound, but other water-soluble silicon compounds such as tetraethyl silicate and water-soluble siloxane derivatives can also be used.

[0059] The spinning solution has a ratio of aluminum derived from basic aluminum chloride to silicon derived from silicon compounds, Al ２ O ３ and SiO ２ Converted to a weight ratio, it is usually 99:1 to 65:35, preferably 99:1 to 70:30, and it is preferable that the aluminum concentration is 170 to 210 g / L.

[0060] If the amount of silicon compounds in the spinning solution is less than the above range, the alumina constituting the short fibers is more likely to become α-alumina, and moreover, the short fibers are more likely to become brittle due to the coarsening of the alumina particles. On the other hand, if the amount of silicon compounds in the spinning solution is more than the above range, mullite (3Al ２ O ３ ・2SiO ２ Silica (SiO) produced together with ) ２ The amount of ) increases, which tends to reduce heat resistance.

[0061] Even when the aluminum concentration in the spinning solution is 170 to 210 g / L, an appropriate viscosity of the spinning solution is obtained, and short fibers with a predetermined average fiber diameter and a sharp fiber diameter distribution can be obtained. The preferred concentration of aluminum in the spinning solution is 180 to 200 g / L.

[0062] The above spinning solution is an aqueous solution of basic aluminum chloride with the above Al ２ O ３ SiO ２ It is prepared by adding a ratio of silicon compound and organic polymer, and concentrating the mixture so that the aluminum concentration falls within the above range.

[0063] ≪Blowing≫ Spinning, that is, the fiberization of the spinning solution, is usually carried out by a blowing method in which the spinning solution is supplied into a high-speed spinning airflow, thereby obtaining an alumina / silica-based fiber precursor. There are no particular restrictions on the structure of the spinning nozzle used in the above spinning process, but a structure in which the airflow blown out from the air nozzle and the spinning solution flow pushed out from the spinning solution supply nozzle are parallel flows, and moreover, the parallel flow of air is sufficiently rectified to come into contact with the spinning solution, is preferred, for example, as described in Japanese Patent Publication No. 2602460.

[0064] In spinning, it is preferable that, first, sufficiently stretched fibers are formed from the spinning solution under conditions where the evaporation of moisture and the decomposition of the spinning solution are suppressed, and then these fibers are dried quickly. To achieve this, it is preferable to change the atmosphere from a state that suppresses the evaporation of moisture to a state that promotes the evaporation of moisture during the process from when the fibers are formed from the spinning solution until they reach the fiber collector.

[0065] The alumina / silica fiber precursor is collected by a fiber collector. The fiber collector has an endless belt made of wire mesh, which is positioned approximately perpendicular to the spinning airflow. The endless belt is rotated, and the spinning airflow containing the alumina / silica fiber precursor is made to collide with it. This results in a continuous sheet-like thin layer of alumina / silica fiber precursor.

[0066] The basis weight of this thin sheet is preferably 10 to 200 g / m². ２ Particularly preferred is 30 to 100 g / m². ２ This is the extent of it, but it is not limited to this.

[0067] The thin sheets described above can be further laminated. Specifically, for example, the thin sheets can be continuously drawn out and sent to a folding device, where they can be folded to a predetermined width and stacked. At this time, the thin sheets can be continuously moved in a direction perpendicular to the folding direction. This allows for the creation of laminated sheets. By laminating the thin sheets in this manner, the basis weight (weight) of the laminated sheets becomes uniform throughout the entire sheet. As the folding device described above, the one described in Japanese Patent Application Publication No. 2000-80547 can be used.

[0068] The laminated sheet is preferably formed by laminating five or more thin sheets, more preferably eight or more thin sheets, and particularly preferably 10 to 80 thin sheets. However, the number of layers is not limited thereto.

[0069] <Needling Process> The laminated sheet obtained in the spinning process is subjected to a needling process in which barbed needles are inserted and removed. This yields a molded body of alumina / silica fiber precursor. The needling process may be performed from only one side or from both sides. Preferably, it is performed from both sides. In the needling process, the rate of multiple needles is also adjusted by changing the transport speed of the laminated sheet, etc. (multiple needle needling process).

[0070] The needle is preferably inserted and withdrawn perpendicular to the sheet surface of the laminated sheet (the surface perpendicular to the thickness direction of the laminated sheet). The needle is inserted deeper than the center in the thickness direction of the laminated sheet. The needle may also be inserted so as to penetrate the laminated sheet in the thickness direction.

[0071] In this way, when needleing is performed, at least some of the fibers are extended in the approximate thickness direction by the needle at the points where the needle is inserted and removed. As a result, needle marks are formed on the surface of the molded body of the alumina / silica fiber precursor. Within the molded body of the alumina / silica fiber precursor, bundles of alumina / silica fibers that extend in the approximate thickness direction are called warp threads. In the case of multiple needle marks, fibers extended in the approximate thickness direction by other needles are added to the already formed warp threads, forming thicker warp threads.

[0072] Needling is performed to adjust the residual surface pressure after high-temperature cycling of alumina / silica fiber molded bodies and to suppress deformation during press-fitting by forming warp threads.

[0073] The needle marks may penetrate the molded body of the alumina / silica fiber precursor, or they may penetrate from one mat surface and extend without reaching the other mat surface.

[0074] <Firing Process> The gripping material 1 of this disclosure is preferably an alumina / silica fiber molded body obtained by firing a molded body of an alumina / silica fiber precursor. The firing after the needling treatment is usually carried out at a temperature of 900°C or higher, preferably 1000 to 1300°C. A firing temperature of 900°C or higher is preferable because it allows for sufficient crystallization and yields alumina / silica fibers with excellent strength. A firing temperature of 1300°C or lower is also preferable because it prevents excessive grain growth of the fiber crystals and yields alumina / silica fibers with appropriate strength.

[0075] <Die-cutting process> After the firing process, the gripping material 1 is obtained by die-cutting or the like on the alumina / silica fiber molded body.

[0076] [Applications of the gripping material] There are no particular limitations on the applications of the gripping material 1 of this disclosure, and it can be widely used in vehicles / machinery such as automobiles and construction vehicles in which a catalyst support is arranged inside a metal casing. In particular, the gripping material 1 is useful as a gripping material for exhaust gas purification devices mounted on automobiles.

[0077] The inorganic fiber molded body constituting the gripping material 1 of this disclosure does not contain a binder, so the catalyst support is less likely to detach from the gripping material 1 during the first combustion. Additionally, it is possible to eliminate off-odors caused by the combustion of organic binders, sensor malfunctions caused by binder components during combustion, etc. Examples of binders include inorganic binders and organic binders. Examples of inorganic binders include silica sol and / or alumina sol. Examples of organic binders include synthetic rubbers such as acrylic rubber and nitrile rubber; water-soluble polymer compounds such as carboxymethylcellulose and polyvinyl alcohol; thermoplastic resins and thermosetting resins.

[0078] [Exhaust Gas Purification Device] The exhaust gas purification device comprises a catalyst support, a metal casing covering the outside of the catalyst support, and a gripping member positioned between the catalyst support and the casing. The exhaust gas purification device of this disclosure uses the gripping member 1 for the exhaust gas purification device of this disclosure as the gripping member. The exhaust gas purification device of this disclosure exhibits minimal deformation of the gripping member 1 during press-fitting and high residual surface pressure after high-temperature cycling, resulting in good gripping performance of the catalyst support throughout its entire lifecycle after assembly.

[0079] Furthermore, there are no particular restrictions on the configuration of this exhaust gas purification device, and this disclosure can be applied to various types of exhaust gas purification devices comprising a catalyst support, a casing, and a gripping member for the catalyst support.

[0080] The following examples are for illustrative purposes only and are not intended to limit the technical scope of the present invention in any way.

[0081] The methods for measuring and evaluating the various physical properties and characteristics of each inorganic fiber molded article produced in the examples and comparative examples are as follows.

[0082] <Method of peeling> A test piece measuring 50 mm in width and 150 mm in length was cut out from an inorganic fiber molded body, and a 30 mm deep cut was made in the center of the thickness of one end face 10e of this test piece 10. As shown in Figure 2, both ends formed by the cut were grasped with a jig 12, and then the test piece 10 was set on a tensile testing machine and pulled in opposite directions perpendicular to the mat surface at a speed of 500 mm / min to tear the test piece 10 into two.

[0083] <Method for measuring needle mark density> In this disclosure, when the above peeling method was performed, the inorganic fiber molded body was cut into a 50 mm x 50 mm square to be used as a sample, visible light was shone on one side of the inorganic fiber molded body, and the number of light spots and warp threads transmitted to this peeled surface was counted to count the total number of needle marks per unit area. ２ The number of needle marks per area was defined as the needle mark density.

[0084] <Multiple Needle Density> The multiple needle density was calculated using Equation 1 above. Here, the measured needle mark density is the measured value obtained by the needle mark density measurement method described above. The theoretical needle mark density is the theoretical value of the needle mark density calculated assuming that there are no multiple needle marks.

[0085] <Number of Effective Warp Threads> In this disclosure, when the above peeling method is performed, among all warp threads F (Figure 3) protruding from both peeling surfaces (one peeling surface 10a and the other peeling surface 10b) per unit area (50 mm x 50 mm), warp threads with a diameter of 100 μm or more and a protruding length of 2 mm or more are defined as effective warp threads, and their number is counted. The unit area (50 mm x 50 mm) for measuring each value related to warp threads is any area of ​​the test piece 10 (150 mm x 50 mm), avoiding the part where a 30 mm deep cut is made in the center of the thickness.

[0086] <Total Volume V of Effective Warp Threads> After performing the above peeling method, among all the warp threads F (Figure 3) protruding from both peeled surfaces (one peeled surface 10a and the other peeled surface 10b) per unit area (50 mm x 50 mm), warp threads with a diameter of 100 μm or more and a protruding length of 2 mm or more were defined as effective warp threads in that range. Their number, diameter (thickness), and length were measured, and the total volume of effective warp threads was determined. The diameter, length, and number of the above effective warp threads were measured by observing the peeled surface with a digital microscope (Keyence Corporation, VHX-5000, magnification 10x).

[0087] <Average volume of effective warp threads per needle mark> The average volume of effective warp threads per needle mark was calculated as V / n, which is the sum of the volumes (total volume) V of all effective warp threads present on both peeled surfaces (one peeled surface and the other peeled surface) per unit area (50 mm x 50 mm) when the above peeling method is performed, divided by the number of needle marks n per unit area.

[0088] <Average volume per effective warp thread> The average volume per effective warp thread was calculated by dividing the total volume V by the number of effective warp threads N.

[0089] <Organic Binder Amount> The amount of organic binder was determined from the ratio of the weight of the organic binder to the weight of the inorganic fiber molded product (total weight of inorganic fibers + organic binder).

[0090] <Hot Extraction Test> The GBD of the inorganic fiber molded body after press-fitting was 0.36 g / cm³. ３ The size of the catalyst support and SUS pipe were selected accordingly. An assembly in which an inorganic fiber molded material was wound around the catalyst support was pressed into the SUS pipe. While pushing this catalyst support at a speed of 0.05 mm / min, the catalyst support was heated at 10°C / min after 40 minutes. The average value of the extraction load at room temperature from 30 to 40 minutes after the start of the test and the minimum value of the extraction load during heating were recorded, and the load reduction rate was calculated from Equation 2 below. The extraction load is a value measured by a load cell.

[0091]

[0092] <Room Temperature Press-Fit Test> GBD = 0.3 In the room temperature press-fit test, the GBD of the inorganic fiber molded body after press-fitting was 0.30 g / cm³. ３ The sizes of the catalyst support and SUS pipe are selected accordingly. When winding the inorganic fiber molded body around the catalyst support, the inorganic fiber molded body is aligned with the lower end of the catalyst support. After winding, the distance from the upper end of the inorganic fiber molded body to the upper end of the catalyst support is measured at five points in the circumferential direction on both the outer circumference (A) and inner circumference (B) of the inorganic fiber molded body. The distance from the lower end of the inorganic fiber molded body to the lower end of the catalyst support is also measured at five points in the circumferential direction on the inner circumference (C). After measurement, the catalyst support with the wound inorganic fiber molded body is pressed into the SUS pipe using a jig. After pressing is complete, the distance from the upper end of the inorganic fiber molded body to the upper end of the catalyst support is measured again at five points in the circumferential direction on both the outer circumference (A') and inner circumference (B') of the mat. The distance from the lower end of the inorganic fiber molded body to the lower end of the catalyst support is also measured at five points on the inner circumference (C') of the inorganic fiber molded body.

[0093] To illustrate with an example, Figure 5(A) is a partially schematic cross-sectional view of the assembly 3 before press-fitting, in which the gripping material 1, made of an inorganic fiber molded body, is wound around the catalyst support 2, and Figure 5(B) is a partially schematic cross-sectional view of the assembly 3 after press-fitting is complete. The measurement results were evaluated using the following formulas: Deformation amount = (B' - A') - (B - A) Elongation amount = (B' - C') - (B - C) Total deformation amount = Deformation amount + Elongation amount

[0094] <Effective Area> The effective area is calculated by multiplying the effective height by the length of the gripping member. Using the example in Figure 5(B), the effective height (indicated by H in Figure 5(B)) refers to the distance from the upper end of the inner circumference side (the side in contact with the catalyst carrier 2) of the gripping member 1 to the lower end of the outer circumference side (the side in contact with the casing) of the gripping member 1 after the assembly 3 has been pressed into the casing. The length of the gripping member 1 is the circumferential length of the inner surface of the gripping member 1 in the assembled state.

[0095] <Room Temperature Press-Fit Test> GBD = 0.4 The above-mentioned room temperature press-fit test was performed at GBD = 0.4.

[0096] <Method for measuring residual surface pressure> The residual surface pressure was determined by the following method.

[0097] An inorganic fiber molded body was compressed for 30 minutes at a GBD (bulk density) of 0.30. Then, the upper and lower plates were heated to 600°C, and the GBD was set to 0.27 when released and 0.30 when compressed. This release and compression cycle was repeated 1000 times. During this process, the surface pressure value at the first release (GBD = 0.27) and the surface pressure value at the 1000th release (GBD = 0.27) were measured.

[0098] The surface pressure value (kPa) at the 1000th opening was defined as the residual surface pressure (surface pressure after high-temperature cycling).

[0099] [Example 1] A silica sol was added to an aqueous solution of basic aluminum chloride (aluminum content 165 g / L, Al / Cl = 1.8 (atomic ratio)), and the composition of the final alumina fibers was Al ２ O ３ SiO ２ The ingredients were added in a ratio of 72:28 (by weight), and then polyvinyl alcohol was added. After that, the mixture was concentrated to prepare a spinning solution with a viscosity of 70 poise (25°C) and an alumina-silica content of approximately 35% by weight.

[0100] The above spinning solution was spun using the blowing method. As the spinning nozzle, a spinning nozzle with the same structure as that described in Figure 6 of Japanese Patent Publication No. 2602460 was used. Furthermore, for cotton collection, a fiber collector was used in which an endless belt made of wire mesh was set approximately perpendicular to the spinning airflow, and the spinning airflow containing the alumina / silica fiber precursor was made to collide with the endless belt while it was rotating. In this way, the alumina / silica fiber precursor was recovered as a continuous sheet (thin sheet).

[0101] The thin sheets were coated with an anti-friction agent by spray, then continuously pulled out and sent to a folding device, where they were folded to a predetermined width and stacked while being continuously moved in a direction perpendicular to the folding direction to form laminated sheets. The folding device used was one with the same structure as that described in Japanese Patent Application Publication No. 2000-80547.

[0102] In the needle punching process, the laminated sheet is punched with a needle punching machine, resulting in a post-fired alumina / silica fiber molded body with a needle mark density of 10.6 punches / cm². ２ The material was punched to achieve a multi-needle ratio of 58%. This resulted in a molded body of alumina / silica fiber precursor.

[0103] Subsequently, the molded alumina / silica fiber precursor is calcined at 1200°C to obtain a basis weight of 1200 g / m². ２ An inorganic fiber molded body (alumina / silica fiber molded body) consisting of crystalline alumina / silica fibers was obtained. Sintering was performed in a gas furnace, heating to 1200°C at a rate of 5°C / min, holding at 1200°C for 30 minutes, and then natural cooling. This inorganic fiber molded body is not impregnated with a binder.

[0104] The composition ratio of this crystalline alumina / silica fiber was alumina / silica = 72 / 28 (by weight), and the average fiber diameter (average value of 100 fibers) of the crystalline alumina / silica fiber, measured by microscopic observation of the inorganic fiber molded body, was 5.5 μm.

[0105] The measurement results and other information for the obtained inorganic fiber molded material are shown in Table 1.

[0106] [Example 2] Basis weight 1400 g / m² ２ Needle mark density: 10.0 pinpoint strikes / cm² ２ The procedure was the same as in Example 1, except that the punching was done so that the multiple needle rate was 50%.

[0107] [Example 3] Basis weight 1700 g / m² ２ Needle mark density: 14.7 pinches / cm² ２ The procedure was the same as in Example 1, except that the punching was done so that the multiple needle rate was 45%.

[0108] [Example 4] Basis weight 2000 g / m² ２ Needle mark density: 12.4 pinch / cm² ２ The procedure was the same as in Example 1, except that the punching was done so that the multiple needle rate was 50%.

[0109] [Comparative Example 1] Needle mark density: 14.1 pinches / cm ２ The procedure was the same as in Example 1, except that the material was punched to achieve a multi-needle ratio of 40% and an organic binder was impregnated to an amount of 3.8% of the weight of the inorganic fiber molded body.

[0110] [Comparative Example 2] Needle mark density: 4.8 pinches / cm ２ The procedure was the same as in Example 1, except that the punching was done so that the multiple needle rate was 10%.

[0111] [Comparative Example 3] Basis weight 1700 g / m² ２ Needle mark density: 5.3 strikes / cm² ２ The procedure was the same as in Example 1, except that the punching was done so that the multiple needle rate was 2%.

[0112] [Comparative Example 4] Basis weight: 1700 g / m² ２ Needle mark density: 25.9 pinpoint strikes / cm² ２ The procedure was the same as in Example 1, except that the punching was done to achieve a multiple needle ratio of 9%.

[0113] [Comparative Example 5] Basis weight 1400 g / m² ２ Needle mark density: 18.8 strikes / cm² ２ The procedure was the same as in Example 1, except that the punching was done so that the multiple needle rate was 3%.

[0114] [Comparative Example 6] Basis weight 1275 g / m² ２ Needle mark density: 39.7 strikes / cm² ２ The procedure was the same as in Example 1, except that the punching was performed so that the multiple needle rate was 0%.

[0115]

[0116] As shown in Table 1, the inorganic fiber molded articles of Examples 1 to 4 had an appropriate needle mark density and an appropriate number of effective warp threads, resulting in a small overall deformation during press-fitting in the room temperature press-fitting test, maintenance of residual surface pressure after high-temperature cycling, and a small load reduction rate in the hot extraction test.

[0117] The inorganic fiber molded body of Comparative Example 1, due to the inclusion of an organic binder, showed a large load reduction rate in the hot extraction test. If the inorganic fiber molded body of Comparative Example 1 were used in an automobile, there is a high possibility that the catalyst support would detach during the initial combustion.

[0118] The inorganic fiber molded article of Comparative Example 2 had a lower needle mark density than that of the inorganic fiber molded article of Example 1 with the same basis weight, and also had fewer effective warp threads than the inorganic fiber molded article of Example 1 with the same basis weight. As a result, the total deformation in the room temperature press-fit test was larger. This total deformation increased as the GBD increased. A large total deformation reduces the effective area, which in turn reduces the gripping force on the catalyst support. Therefore, when using the inorganic fiber molded article of Comparative Example 2, there is a high possibility that the catalyst support will detach.

[0119] The inorganic fiber molded article of Comparative Example 3 had a lower needle mark density than that of the inorganic fiber molded article of Example 3 with the same basis weight, and also had fewer effective warp threads than the inorganic fiber molded article of Example 3 with the same basis weight. As a result, the total deformation in the room temperature press-fit test was larger. A larger total deformation reduces the effective area, which in turn reduces the gripping force on the catalyst support. Therefore, when using the inorganic fiber molded article of Comparative Example 3, there is a high possibility that the catalyst support will detach.

[0120] The inorganic fiber molded article of Comparative Example 4 had a higher needle mark density than the inorganic fiber molded article of Example 3 with the same basis weight, resulting in lower residual surface pressure. Due to the lower residual surface pressure, there is a high possibility of detachment during long-term use if the inorganic fiber molded article of Comparative Example 4 is used.

[0121] The inorganic fiber molded article of Comparative Example 5 had a greater number of effective warp threads than the inorganic fiber molded article of Example 2 with the same basis weight, and its needle mark density was higher than that of the inorganic fiber molded article of Example 2 with the same basis weight, resulting in lower residual surface pressure. Due to the lower residual surface pressure, there is a high possibility of shedding during long-term use if the inorganic fiber molded article of Comparative Example 5 is used.

[0122] The inorganic fiber molded article of Comparative Example 6 had a greater number of effective warp threads than the inorganic fiber molded article of Example 1 with a similar basis weight, and its needle mark density was higher than that of the inorganic fiber molded article of Example 1 with a similar basis weight, resulting in lower residual surface pressure. Due to the lower residual surface pressure, there is a high possibility of shedding during long-term use if the inorganic fiber molded article of Comparative Example 6 is used.

[0123] 2...Catalyst support, 3...Gripping material for exhaust gas purification device, 6...Casing, 8...Exhaust gas purification device, 10...Test piece, 10e...End face, 12...Gripping jig.

Claims

1. A gripping material for an exhaust gas purification device, comprising an inorganic fiber molded body composed of inorganic fibers and containing no binder, wherein the inorganic fiber molded body has needle marks extending in the thickness direction, and the needle marks contain warp threads made of the inorganic fibers extending in the thickness direction, with a needle mark density of 8.0 to 18.0 marks / cm². ２ The number of effective warp threads is 2.8 to 6.0 threads / cm. ２ Therefore, the average volume per effective warp thread is 1.5 to 4.0 mm². ３ / strand, and the effective warp strands represent warp strands with a diameter of 100 μm or more and a protruding length of 2 mm or more among all warp strands protruding from one peeled surface and the other peeled surface in a 50 mm x 50 mm area when the peeling method described below is performed.Gripping material for exhaust gas purification device.<Peeling method>A test piece with a width of 50 mm and a length of 150 mm is cut out from an inorganic fiber molded body.Next, a cut to a depth of 30 mm is made in the center of the thickness of one end face of this test piece, and after supporting both ends formed by the cut in a gripping jig, it is set in a tensile testing machine.At a speed of 500 mm / min, both ends of the test piece are pulled in opposite thickness directions to tear it in two.

2. A gripping material for an exhaust gas purification device, comprising an inorganic fiber molded body composed of inorganic fibers and without a binder, wherein the inorganic fiber molded body has needle marks extending in the thickness direction, and the needle marks contain warp threads made of the inorganic fibers extending in the thickness direction, with a needle mark density of 8.0 to 18.0 marks / cm². ２ The number of effective warp threads is 2.8 to 6.0 threads / cm. ２ A gripping material for an exhaust gas purification device, wherein the residual surface pressure after high-temperature cycling is 30 kPa or more, and the effective warp threads represent warp threads with a diameter of 100 μm or more and a protruding length of 2 mm or more among all warp threads protruding from one peeled surface and the other peeled surface in a 50 mm x 50 mm area when the peeling method described below is performed. <Peeling method> A test piece with a width of 50 mm and a length of 150 mm is cut out from an inorganic fiber molded body. Next, a 30 mm deep cut is made in the center of the thickness of one end face of this test piece, and after gripping both ends formed by the cut and supporting them in a jig, it is set in a tensile testing machine. At a speed of 500 mm / min, both ends of the test piece are pulled in opposite thickness directions to tear it in two.

3. The total volume of the effective warp threads is 6.5 to 10.0 mm². ３ / cm ２ A gripping material for an exhaust gas purification device according to claim 1 or 2.

4. Basis weight is 1000-2000 g / m² ２ A gripping material for an exhaust gas purification device according to claim 1 or 2.

5. The gripping material for an exhaust gas purification device according to claim 1, wherein the residual surface pressure after a high-temperature cycle is 30 kPa or more.

6. An exhaust gas purification device comprising: a catalyst support; a casing covering the outside of the catalyst support; and a gripping member for an exhaust gas purification device according to claim 1 or 2, disposed between the catalyst support and the casing.

Images