Holder for exhaust gas purification device, and exhaust gas purification device

Abstract

The grip for an exhaust gas purification device is provided with an inorganic fiber molded body comprising inorganic fibers, and does not contain a binder. The inorganic fiber molded body has stitches extending in the thickness direction, the stitches have longitudinal strands formed of the inorganic fibers extending in the thickness direction, the stitch density is 8.0 / cm < 2 > to 18.0 / cm < 2 >, the number of effective longitudinal strands is 2.8 / cm < 2 > to 6.0 / cm < 2 >, and the thickness of the inorganic fibers is less than the thickness of the inorganic fibers. The effective vertical filaments represent vertical filaments having a diameter of 100 m or more and a protruding length of 2 mm or more among all of the vertical filaments protruding from one peeling surface and the other peeling surface within a range of 50 mm * 50 mm when the following peeling method is performed.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a holding member for an exhaust purification device and an exhaust purification device. BACKGROUND

[0002] An inorganic fiber molded body in which inorganic fibers typified by ceramic fibers are molded into a mat shape is used for industrial heat insulating members, refractory members, sealing members, and the like, which are exposed to high-temperature conditions. In recent years, the inorganic fiber molded body is also used as a holding member for an exhaust purification device of an automobile (hereinafter also referred to as a "holding member").

[0003] Patent Literature 1 discloses a holding seal member disposed between a catalyst carrier in an exhaust purification catalytic converter and a shell covering the outer side thereof. In the holding seal member, an adhesive such as an organic adhesive is adhered to a mat in which inorganic fibers are disposed in a mat shape.

[0004] Further, in the production of an exhaust purification device for an automobile, it is known that an assembly (hereinafter also referred to as an "assembly") in which a holding member is wound around a catalyst carrier is disposed in a housing by press-fitting.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent No. 4042305 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] In the holding seal member described in Patent Literature 1, the organic adhesive dissolves at the time of initial combustion. At this time, the organic adhesive functions as a lubricant, and thus the surface pressure of the holding seal member is sometimes reduced. Therefore, in the holding seal member described in Patent Literature 1, the catalyst carrier can fall off at the time of initial combustion.

[0010] Further, it is known that the holding member is deformed when the assembly is press-fitted into the housing. If the amount of deformation increases, the effective area of the holding member, which contributes to the force for holding the catalyst carrier, decreases. As a result, the catalyst carrier can fall off.

[0011] Furthermore, it is known that the surface pressure of the holding member, which contributes to the force for holding the catalyst carrier, decreases in the case where the holding member is used for a long time. Therefore, the catalyst carrier can fall off after a long time of use.

[0012] According to the foregoing, an example of the object of the present application is to provide a holding member for an exhaust purification device and an exhaust purification device that suppress catalyst carrier peeling from a housing throughout the life cycle from immediately after use initiation to long-term use. Other objects of the present application will become apparent from the description of this specification.

[0013] Solution to the problem

[0014] The present disclosure includes, for example, the subject matter described in the following.

[0015] Item 1.

[0016] A holding member for an exhaust purification device, wherein The holding member for an exhaust purification device includes an inorganic fiber molded body composed of inorganic fibers, and does not include a binder, The inorganic fiber molded body has a needle trace extending in a thickness direction, and a longitudinal filament formed of the inorganic fibers extending in the thickness direction is present in the needle trace, The needle trace density is 8.0 pieces / cm 2 ~ 18.0 pieces / cm 2 , The number of effective longitudinal filaments is 2.8 pieces / cm 2 ~ 6.0 pieces / cm 2 , The effective longitudinal filament indicates a longitudinal filament having a diameter of 100 µm or more and a protruding length of 2 mm or more from one peeling surface and the other peeling surface in a range of 50 mm x 50 mm when a peeling method described below is performed, <Peeling method> A test piece having a width of 50 mm and a length of 150 mm is die-cut from the inorganic fiber molded body; then, a 30 mm deep cut groove is made in the thickness center of one end surface of the test piece, and after the both ends of the test piece formed by the cut groove are supported in a clamping jig, it is set in a tensile testing machine; the both ends of the test piece are stretched in opposite thickness directions at a speed of 500 mm / min to tear into two pieces.

[0017] Item 2.

[0018] The holding member for an exhaust purification device according to item 1, wherein the total volume of the effective longitudinal filaments is 6.5 mm 3 / cm 2 ~ 10.0 mm 3 / cm 2 .

[0019] Item 3.

[0020] The holding member for exhaust gas purification device according to any one of items 1 to 3, wherein the unit area weight of the holding member for exhaust gas purification device is 1000 g / m 2 ~2000 g / m 2 .

[0021] Item 4.

[0022] The holding member for exhaust gas purification device according to any one of items 1 to 3, wherein the average volume of each of the effective longitudinal threads is 1.5 mm 3 / thread ~ 4.0 mm 3 / thread.

[0023] Item 5.

[0024] The holding member for exhaust gas purification device according to any one of items 1 to 4, wherein the residual surface pressure after high-temperature cycle of the holding member for exhaust gas purification device is 30 kPa or more.

[0025] Item 6.

[0026] An exhaust gas purification device including: a catalyst carrier; a housing covering an outer side of the catalyst carrier; and The holding member for exhaust gas purification device according to any one of items 1 to 5 is disposed between the catalyst carrier and the housing.

[0027] Effects of the Invention

[0028] According to the present disclosure, a holding member for exhaust gas purification device and an exhaust gas purification device that can suppress the catalyst carrier from falling off from the housing throughout the life cycle from immediately after use initiation to long-term use are provided. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 (A) to (D) of FIG. 1 are explanatory diagrams showing each process of pressing the catalyst carrier having the holding member wound therearound into the housing.

[0030] Figure 2 is an explanatory diagram of a test piece formed with a cutout.

[0031] Figure 3 is an explanatory diagram of a peeling method.

[0032] Figure 4 (A) of FIG. 6 is a partial schematic cross-sectional view showing a force applied to the holding member when the assembly of FIG. 5 is pressed into the housing. Figure 1 Figure 4 ​(B) is a partial schematic cross-sectional view showing the deformation of the gripping members when an assembly of gripping members with a small number of effective longitudinal filaments is pressed into the housing. Figure 4 (C) is a partial schematic cross-sectional view showing the deformation of the gripping members when an assembly of gripping members with a large number of effective longitudinal filaments is pressed into the housing.

[0033] Figure 5 (A) is a partial side sectional view of the assembly in its pre-pressed state. Figure 5 (B) is a partial side sectional view of the assembly in which the holding member 1 is deformed relative to the catalyst catalyst carrier 2 by pressing. Detailed Implementation

[0034] In this specification, unless otherwise expressly stated in this specification or clearly contradicted in the context, nouns without numeral qualifiers are defined as including both singular and plural forms.

[0035] In this specification, "possessing" also includes the concepts of "substantially consisting of only" and "consisting of only".

[0036] In the numerical ranges described in stages in this specification, the upper or lower limit of a certain stage's numerical range can be arbitrarily combined with the upper or lower limits of the numerical ranges of other stages. Furthermore, the upper or lower limit of the numerical range described in this specification can also be replaced with the values ​​shown in the embodiments or values ​​uniquely derived from the embodiments. Moreover, in this specification, numerical values ​​connected by "~" refer to a numerical range including the values ​​before and after the "~" as both the lower and upper limits.

[0037] The embodiments included in this disclosure will be further described below. It should be noted that the embodiments described below illustrate an example of a representative embodiment of this disclosure and are not intended to limit the scope of the invention.

[0038] [Holding component for exhaust gas purification device]

[0039] like Figure 1 As shown in (A)-(D), the exhaust gas purification device of this disclosure uses a holding member 1 (hereinafter also referred to as "holding member 1") in an assembly 3 formed by winding the holding member 1 around a catalyst carrier 2, which is housed within a metal housing 6. The holding member 1 is positioned between the catalyst carrier 2 and the housing 6. The holding member 1 serves as a buffer for the catalyst carrier 2, holding the catalyst carrier 2. The holding member 1 is obtained by die-cutting or similar processes on the inorganic fiber molded body of this disclosure. Figure 1As shown in (A), the holding member 1 has long sides 1g and 1h that are substantially straight and 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 has straight portions on both sides and a protruding portion 1m divided by three sides that are substantially straight, which is sandwiched between the straight portions and protrudes outward from the straight portions. The short side 1k has straight portions on both sides and a recessed portion 1n divided by three sides that are substantially straight, which is sandwiched between the straight portions and protrudes inward from the straight portions.

[0040] In the present disclosure, the characteristics and the like of the holding member 1 are the same as those of the inorganic fiber molded body. Therefore, hereinafter, in the case of explaining the characteristics of the holding member 1, the characteristics of the inorganic fiber molded body are sometimes used.

[0041] The holding member 1 for an exhaust purification device of the present disclosure is composed of an inorganic fiber molded body composed of inorganic fibers, and does not contain a binder. The inorganic fiber molded body has a needle trace extending in a thickness direction, In the needle trace, there are longitudinal filaments formed of the inorganic fibers extending in the thickness direction, The needle trace density is 8.0 pieces / cm 2 to 18.0 pieces / cm 2 , The number of effective longitudinal filaments is 2.8 pieces / cm 2 to 6.0 pieces / cm 2 , The effective longitudinal filaments indicate, among all the longitudinal filaments protruding from one peeling surface and the other peeling surface in a range of 50 mm x 50 mm when the following peeling method is performed, the longitudinal filaments having a diameter of 100 µm or more and a protruding length of 2 mm or more.

[0042] <Peeling method>

[0043] A test piece 10 having a width of 50 mm and a length of 150 mm was die-cut from the inorganic fiber molded body. Next, as shown in (A), a cut groove having a depth of 30 mm was formed in the center of the thickness of one end surface 10e of the test piece 1. Next, as shown in (B), after the both ends of the test piece formed by the cut groove were supported in a clamping jig 12, it was set in a tensile testing machine. The both ends were stretched in opposite thickness directions at a speed of 500 mm / min, and torn into two pieces. Figure 2 Figure 3

[0044] <Inorganic fiber molded body>

[0045] ​​In one aspect of this disclosure, the inorganic fiber molded body is obtained by firing a molded body of an inorganic fiber precursor. In another aspect, the molded body of the inorganic fiber precursor is obtained by needle-punching a laminated sheet. In another aspect, the laminated sheet is obtained by stacking thin sheets. In another aspect, the thin sheet is obtained by aggregating the inorganic fiber precursor. In another aspect, the inorganic fiber precursor is obtained by spinning a spinning solution using a spray spinning method. The inorganic fiber molded body is a pad-shaped body with a specified thickness. Hereinafter, the surface of the inorganic fiber molded body perpendicular to the thickness direction is sometimes referred to as the pad surface. Furthermore, the side surface (the surface in the thickness direction) of the inorganic fiber molded body perpendicular to the pad surface is sometimes referred to as the end face.

[0046] <Inorganic Fibers>

[0047] The inorganic fibers constituting the inorganic fiber molded articles of this disclosure are not particularly limited, and examples include individual or composite fibers such as silica, alumina / silica, zirconium oxide, spinel, and titanium dioxide containing the same. However, alumina / silica-based fibers, especially crystalline alumina / silica-based fibers, are particularly preferred. The alumina / silica composition ratio of the alumina / silica-based fibers is preferably in the range of 60–95 / 40–5 by weight, more preferably in the range of 70–84 / 30–16, and particularly preferably in the range of 70–76 / 30–24.

[0048] Furthermore, the inorganic fibers are preferably short fibers. There are no particular limitations on the fiber length of the inorganic fibers, but it is preferably 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 µm to 10 µm, more preferably 5 µm to 8 µm. If the average fiber diameter of the inorganic fibers is 8 µm or less, the inorganic fiber molded body has moderate resilience, and is therefore preferred. Furthermore, if the average fiber diameter of the inorganic fibers is 5 µm or more, the amount of dust generated in the air can be suppressed, and is therefore preferred.

[0049] <Unit area weight and thickness of inorganic fiber molded bodies>

[0050] The weight per unit area (mass per unit area) of the inorganic fiber molded body disclosed herein is appropriately determined according to the application, but is preferably 1000 g / m². 2 The above, more preferably 1200g / m 2 That's all. Furthermore, from the viewpoint of obtaining a holding member 1 that can suppress the catalyst support 2 from detaching from the shell 6 throughout its entire lifespan, the unit area weight of the inorganic fiber molded body disclosed herein is preferably 1000 g / m². 2 ~2000g / m 2 More preferably 1000g / m2 ~1800g / m 2 More preferably 1200g / m 2 ~1800g / m 2 .

[0051] The thickness of the inorganic fiber molded body disclosed herein is preferably 3 mm or more, more preferably 5 mm or more. Furthermore, the thickness of the inorganic fiber molded body disclosed herein 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.

[0052] For example, Figure 1 (A)-(D) represent the steps involved in pressing assembly 3 into housing 6. Figure 1 In (A), the process of preparing the holding member 1 and the catalyst carrier 2 is shown. Figure 1 In (B), the process of preparing an assembly 3 by winding the holding member 1 around the catalyst carrier 2 and fixing the holding member 1 using a fixing belt 4, etc., is shown. Figure 1 In (C), the process of pressing the assembly 3 into the housing 6 using the clamp 7 is shown. Figure 1 In (D), the process of completing an exhaust purification device 8 having a catalyst carrier 2, a housing 6 covering the outside of the catalyst carrier 2, and a holding member 1 disposed between the catalyst carrier 2 and the housing 6 is shown.

[0053] The greater the unit area weight and thickness of the inorganic fiber molded body disclosed herein, the greater the deformation of the holding member 1 tends to be when it is pressed into the assembly 3. On the other hand, in order to avoid the catalyst carrier 2 from falling off, it is preferable that the deformation of the holding member 1 is small when the assembly 3 is pressed into the shell 6.

[0054] The unit area weight and thickness of the inorganic fiber molded body can be set to the aforementioned range by adjusting the amount of fiber per unit area when stacking the assembly of inorganic fiber precursors constituting the inorganic fiber molded body (hereinafter also referred to as "sheet") using a folding device. Furthermore, the inorganic fiber molded body of this disclosure can be a single structure or a structure formed by bonding multiple inorganic fiber molded bodies, but from the perspective of operability and peel strength at the bonding interface, a single structure is preferred.

[0055] <Needle stitch density>

[0056] Methods for Determining Needle Stamp Density

[0057] In one aspect of this disclosure, the stitch density of the inorganic fiber molded body refers to the density per unit area (per cm²) of the pad surface of the inorganic fiber molded body (obtained by firing a molded body of an inorganic fiber precursor). 2 The number of stitches.

[0058] When visible light is irradiated to the mat surface of the inorganic fiber molded body on which the above-described peeling method is performed, the amount of transmitted light at the needle trace is more than the amount of transmitted light at the region other than the needle trace, and thus the transmitted light is observed as a light spot in the peeling surface. The number of light spots and the number of longitudinal threads obtained by transmitting the light to the peeling surface are counted, and the number of light spots is divided by the sum of the number of longitudinal threads and the area, whereby the needle trace density is obtained.

[0059] That is, visible light is irradiated to one surface of the inorganic fiber molded body, and the number of light spots and the number of longitudinal threads obtained by transmitting the light to the peeling surface are counted, and the number of light spots is divided by the sum of the number of longitudinal threads and the area, whereby the needle trace density is obtained.

[0060] <Preferred range of needle trace density>

[0061] In the present disclosure, the needle trace density, which is the number of needle traces per unit area (1 cm 2 ) of the mat surface of the inorganic fiber molded body, is 8.0 pieces / cm 2 ~ 18.0 pieces / cm 2 . Regarding the needle trace density, the easiness of deformation at the time of press-in of the holding member 1 and the height of the residual surface pressure after the high-temperature cycle of the holding member 1 are in a tradeoff relationship. If the needle trace density is less than 8.0 pieces / cm 2 , the deformation at the time of press-in of the holding member 1 becomes large. If the needle trace density exceeds 18.0 pieces / cm 2 , the residual surface pressure after the high-temperature cycle of the holding member 1 decreases. Therefore, the inorganic fiber molded body satisfying the needle trace density of 8.0 pieces / cm 2 ~ 18.0 pieces / cm 2 can take into account both the difficulty of deformation at the time of press-in of the holding member 1 and the high residual surface pressure after the high-temperature cycle. Both the difficulty of deformation at the time of press-in of the holding member 1 and the high residual surface pressure after the high-temperature cycle contribute to the suppression of the catalyst carrier 2 from falling off the case 6, and thus by satisfying the needle trace density of 8.0 pieces / cm 2 ~ 18.0 pieces / cm 2 , the catalyst carrier 2 can be suppressed from falling off the case 6 throughout the entire life cycle.

[0062] <Longitudinal thread>

[0063] The inorganic fiber molded body of the present disclosure has needle traces formed by needle punching. When needle punching in which a needle with a barb is pulled out / inserted into a laminate is performed, at least a part of the fibers extends in the substantially thickness direction through the needle at the portion where the needle is pulled out / inserted. The bundle of inorganic fibers formed in the substantially thickness direction, which is present inside the inorganic fiber molded body, formed by the needle punching is referred to as a longitudinal thread.

[0064] <Effective filaments>

[0065] In the present disclosure, in implementing the peeling method described above, the total filaments F (filaments F having a diameter of 100 µm or more and a protruding length of 2 mm or more among all the filaments F protruding from both peeling surfaces (one peeling surface 10a and the other peeling surface 10b) in a unit area (50 mm x 50 mm) Figure 3 ) are set as effective filaments. Note that the unit area (50 mm x 50 mm) in which each value related to the filaments F is measured is set to be an arbitrary region avoiding the portion in which a cut groove having a depth of 30 mm is formed in the center of the thickness of the test piece 10 (150 mm x 50 mm).

[0066] The effective filaments have a diameter and a length that function in a manner to adjust the deformation difficulty at the time of pressing in the holding member 1 and the residual surface pressure after the high-temperature cycle.

[0067] <Number of effective filaments>

[0068] In the inorganic fiber molded body of the present disclosure, the number of effective filaments is 2.8 filaments / cm 2 ~ 6.0 filaments / cm 2 .

[0069] If the number of effective filaments is less than 2.8 filaments / cm 2 , the holding member 1 is easily deformed at the time of pressing in. If the number of effective filaments exceeds 6.0 filaments / cm 2 , the residual surface pressure of the holding member 1 after the high-temperature cycle decreases. In one aspect of the present disclosure, the number of effective filaments is 2.8 filaments / cm 2 ~ 5.0 filaments / cm 2 . If within such a range, both the deformation difficulty at the time of pressing in the holding member 1 and the high residual surface pressure after the high-temperature cycle can be taken into account.

[0070] Here, referring to Figure 4 (A), as in (B) to (D) of Figure 1 , the holding member 1 composed of an inorganic fiber molded body is wound around the catalyst carrier 2, and a plurality of filaments extend in the inorganic fiber molded body of the holding member 1. At the time of pressing in the assembly 3 to the housing (reference numeral 6 of (C) of Figure 1 , a shear stress indicated by an arrow in (A) of Figure 4 is applied to the holding member 1. As Figure 4As shown in (B), when using an inorganic fiber molded body with a small number of effective longitudinal filaments 1t, the shear stress of the holding member 1 is weak, and the holding member 1 is prone to deformation during pressing. However, if the number of effective longitudinal filaments 1t is small, the constraint force maintaining the thickness of the inorganic fiber molded body is weak, and therefore the surface pressure applied from the holding member 1 to the catalyst support 2 is relatively high. On the other hand, as Figure 4 As shown in (C), when using an inorganic fiber molded body with a large number of effective longitudinal filaments 1t, the shear stress of the holding member 1 is strong, and the holding member 1 is not easily deformed during pressing. However, if the number of effective longitudinal filaments 1t is large, the constraint force maintaining the thickness of the inorganic fiber molded body is strong, and therefore the surface pressure applied from the holding member 1 to the catalyst carrier 2 is low. The holding member 1 of this disclosure balances the strength relative to the shear stress (difficulty of deformation during pressing) with the high residual surface pressure after high-temperature cycling applied to the catalyst carrier 2, thereby seeking to suppress the catalyst carrier 2 from falling off the shell 6 throughout its entire life cycle.

[0071] <Total volume V of effective longitudinal fibers>

[0072] After performing the above-described peeling method, the number (number of strands) N, diameter (thickness) D, and length (protrusion length from peeling surface 10a or peeling surface 10b) of effective longitudinal filaments protruding from peeling surface 10a and peeling surface 10b are measured using a digital microscope. The magnification of the digital microscope is preferably set to 10x to 20x. The length L is obtained by measuring the portion protruding from peeling surface 10a or peeling surface 10b with a diameter of 100µm or more. The diameter D is a value measured approximately at the midpoint of the length of the portion protruding from peeling surface 10a or peeling surface 10b.

[0073] The total volume V of the effective longitudinal wires within the 50mm×50mm range is calculated by taking the volume (πD) of each of the N effective longitudinal wires. 2 The value is obtained by summing L / 4.

[0074] In the inorganic fiber molded body disclosed herein, the total volume (sum of volumes) V of the effective longitudinal filaments is 6.5 mm. 3 / cm 2 ~10.0mm 3 / cm 2 From the perspective of obtaining a gripper 1 that suppresses deformation during pressing and has high residual surface pressure after high-temperature cycling, this range of total volume is preferred. In one embodiment of this disclosure, the total volume (sum of volumes) V of the effective longitudinal wires is 7.0 mm. 3 / cm 2 ~10.0mm 3 / cm 2If within such a range, both the deformation difficulty of the holding member 1 at the time of press-in and the high residual surface pressure after the high-temperature cycle can be taken into account.

[0075] With the number of effective longitudinal filaments fixed, the smaller the total volume V of the effective longitudinal filaments of the inorganic fiber molded body, the thinner the effective longitudinal filaments, and the weaker the shear stress of the inorganic fiber molded body. Therefore, the holding member 1 is easily deformed at the time of press-in, but the surface pressure applied from the holding member 1 becomes relatively high. On the other hand, the larger the total volume V of the effective longitudinal filaments of the inorganic fiber molded body, the thicker the effective longitudinal filaments, and the stronger the shear stress of the inorganic fiber molded body. Therefore, the holding member 1 is not easily deformed at the time of press-in, but the surface pressure applied from the holding member 1 becomes relatively low. As such, the total volume V of the effective longitudinal filaments of the inorganic fiber molded body of the present disclosure also contributes to taking into account both the strength of the holding member 1 with respect to the shear stress (the difficulty of deformation at the time of press-in) and the height of the residual surface pressure applied to the catalyst carrier 2 after the high-temperature cycle.

[0076] <Multiple needle rate>

[0077] In the present disclosure, a case where a portion formed with a single needle trace is further subjected to needle punching is set as multiple needle punching, and a needle trace formed thereby is set as a multiple needle trace. The multiple needle rate (i.e., the number of multiple needle traces) can be adjusted, for example, by changing the conveyance speed of the laminated sheet in the needle punching process. The multiple needle punching is one example of a method of thickening the longitudinal filaments. The multiple needle rate can be found by the following Equation 1.

[0078] [Equation 1]

[0079] Multiple needle rate (%) = (1 - (measured needle trace density / theoretical needle trace density)) 100 … Equation 1

[0080] The measured needle trace density is a measured value obtained by the above-described needle trace density measurement method. The theoretical needle trace density is a theoretical value of the needle trace density calculated assuming no multiple needle traces.

[0081] In the multiple needle trace, there is a tendency for the longitudinal filaments to be thickened compared to a single needle trace. Therefore, the longitudinal filaments in the multiple needle trace have a tendency to increase in volume. That is, by forming a multiple needle trace, it is possible to increase the total volume V of the effective longitudinal filaments without increasing the needle trace density. As a result, compared to a case where the needle trace density is increased, it is possible to form a more robust (i.e., strong in maintaining the constraint of the thickness of the inorganic fiber molded body) longitudinal filament without excessively reducing the residual surface pressure after the high-temperature cycle. As described above, the multiple needle punching also contributes to taking into account both the strength of the holding member 1 with respect to the shear stress (the difficulty of deformation at the time of press-in) and the height of the residual surface pressure applied to the catalyst carrier 2 after the high-temperature cycle.

[0082] <Average volume of effective longitudinal filaments per stitch>

[0083] The number n of stitches in the above-mentioned 50 mm x 50 mm range is measured in advance by the aforementioned measurement method. The average volume of effective longitudinal filaments per stitch (hereinafter, sometimes referred to as "average volume of effective longitudinal filaments per stitch") is obtained by dividing the above-mentioned total volume V obtained by the peeling method by n.

[0084] That is, the average volume of effective longitudinal filaments per stitch refers to a value V / n obtained by dividing the sum (total volume) V of the volumes of all effective longitudinal filaments present on both peeling surfaces (one peeling surface la and the other peeling surface lb) per unit area (50 mm x 50 mm) at the time of the peeling method by the number n of stitches per unit area. The larger the average volume of effective longitudinal filaments per stitch V / n, the more effectively the needling treatment can be performed, and the more firmly (i.e., strongly maintaining the constraint of the thickness of the inorganic fiber molded body) the effective longitudinal filaments can be formed. The average volume of effective longitudinal filaments per stitch of the inorganic fiber molded body of the present disclosure also contributes to the balance between the strength (difficulty of deformation at the time of pressing) of the holding member 1 with respect to the shear stress and the high degree of the residual surface pressure after the high-temperature cycle applied to the catalyst carrier 2.

[0085] The average volume of effective longitudinal filaments per stitch of the inorganic fiber molded body is preferably 0.40 mm 3 More preferably, 0.45 mm 3 or more. The average volume of effective longitudinal filaments per stitch of the inorganic fiber molded body is preferably 1.0 mm 3 Further preferably, 0.95 mm 3 or more.

[0086] <Average volume of each effective longitudinal filament>

[0087] The average volume of each effective longitudinal filament (hereinafter, sometimes referred to as "average volume of each effective longitudinal filament") is obtained by dividing the above-mentioned total volume V by the number N of effective longitudinal filaments.

[0088] That is, the average volume of each effective longitudinal filament refers to the value V / N obtained by dividing the sum of the volumes (total volume) of all effective longitudinal filaments existing on the two peeling surfaces (one peeling surface 1a and the other peeling surface 1b) per unit area (50mm × 50mm) during the peeling method by the number of effective longitudinal filaments N in that unit area. The larger the average volume V / N of each effective longitudinal filament in the inorganic fiber molded body, the more effectively the needle punching process can be performed, and the more robust (i.e., the stronger the constraint force maintaining the thickness of the inorganic fiber molded body) the effective longitudinal filaments can be formed. The average volume of each effective longitudinal filament in the inorganic fiber molded body of this disclosure also helps to balance the strength of the holding member 1 relative to shear stress (the difficulty of deformation during pressing) and the height of the residual surface pressure after the high-temperature cycle applied to the catalyst carrier 2.

[0089] The average volume of each effective longitudinal filament of the inorganic fiber molded body is preferably 1.0 mm. 3 The above, preferably 1.5mm 3 The above. The average volume of each effective longitudinal filament of the inorganic fiber molded body is preferably 4.0 mm. 3 Hereinafter, 3.5mm is further preferred. 3 the following.

[0090] Residual surface pressure after high-temperature cycling

[0091] In the inorganic fiber molded body disclosed herein, the surface pressure after high-temperature cycling can be determined by the following measurement test. The inorganic fiber molded body is subjected to a GBD (bulk density) of 0.30 g / cm³. 3 After compression for 30 minutes, heat the upper and lower plates to 600℃ and repeat this process 1000 times. The initial open temperature is set to GBD = 0.27 g / cm³. 3 GBD = 0.30 g / cm³ during compression. 3 The opening and compression. At this point, the measurement of the first opening (GBD=0.27g / cm³) was taken. 3 The surface pressure value and the value at the 1000th opening (GBD=0.27g / cm²) 3 The surface pressure value of ). At this time, the surface pressure value (kPa) at the 1000th opening is set as the residual surface pressure after high temperature cycling (also known as residual surface pressure).

[0092] The higher the residual surface pressure of the inorganic fiber molded body after high-temperature cycling, the better it can maintain the excellent holding force of the catalyst support for a longer period of time. Therefore, the residual surface pressure of the inorganic fiber molded body after high-temperature cycling is preferably 30 kPa or more, more preferably 33 kPa or more, and particularly preferably 35 kPa or more. In addition, the higher the residual surface pressure after high-temperature cycling, the more advantageous it is from the perspective of maintaining the holding force for a long time, but the amount of deformation during pressing usually tends to increase. From the viewpoint of suppressing the amount of deformation during pressing, the residual surface pressure of the inorganic fiber molded body after high-temperature cycling is preferably 50 kPa or less, more preferably 45 kPa or less, and particularly preferably 40 kPa or less.

[0093] [Manufacturing method of the gripping component]

[0094] The gripper 1 of this disclosure can be manufactured by methods including spinning, needle punching, firing, and die cutting as described below. However, the gripper 1 of this disclosure can also be manufactured by other methods.

[0095] The following describes an example of the method for manufacturing an alumina / silica-based fiber molded body, which is one example of the method for manufacturing the gripping part. However, the gripping part disclosed herein is not limited to having an alumina / silica-based fiber molded body. As mentioned above, it may also have a molded body made of silica, zirconium oxide, spinel, titanium dioxide or composite fibers thereof.

[0096] <Spinning Process>

[0097] In the spinning process, a spinning solution containing alkaline aluminum chloride, silicon compounds, organic polymers as thickeners, and water is spun by a spray spinning method to obtain a laminate of alumina / silica fiber precursors.

[0098] Preparation of spinning solution

[0099] Alkaline aluminum chloride is Al(OH)₂. 3-x Cl x For example, it can be prepared by dissolving metallic aluminum in an aqueous solution of hydrochloric acid or aluminum chloride. The value of x in the above chemical formula is typically 0.45 to 0.54, preferably 0.5 to 0.53. Silica sol is preferred as the silicon compound, but other water-soluble silicon compounds such as tetraethyl silicate or water-soluble siloxane derivatives can also be used.

[0100] Preferably, the spinning solution has an aluminum ratio derived from basic aluminum chloride and a silicon ratio derived from silicon compounds, which is typically 99:1 to 65:35 based on the weight ratio of Al2O3 to SiO2, and more preferably 99:1 to 70:30, with an aluminum concentration of 170 g / L to 210 g / L.

[0101] When the amount of silicon compounds in the spinning solution is less than the above range, the alumina constituting the short fibers is prone to α-aluminization, and the short fibers are prone to embrittlement due to the coarsening of alumina particles. On the other hand, when the amount of silicon compounds in the spinning solution is greater than the above range, the amount of silicon dioxide (SiO2) formed together with mullite (3Al2O3·2SiO2) increases, and the heat resistance tends to decrease.

[0102] When the aluminum concentration in the spinning solution is between 170 g / L and 210 g / L, a suitable viscosity of the spinning solution can be obtained, resulting in short fibers with a specified average fiber diameter and a narrow fiber diameter distribution. The preferred aluminum concentration in the spinning solution is between 180 g / L and 200 g / L.

[0103] The above spinning solution is prepared by adding a silicon compound and an organic polymer in an amount equal to the above Al2O3:SiO2 ratio to an alkaline aluminum chloride aqueous solution, and concentrating the solution in such a way that the aluminum concentration is within the above range.

[0104] Spinning

[0105] Spinning, or the fiberization of spinning solution, is typically carried out by a jet spinning method that supplies the spinning solution to a high-speed spinning airflow, thereby obtaining an alumina / silica-based fiber precursor. The structure of the spinning nozzle used in the above-mentioned spinning process is not particularly limited; for example, a structure as described in Japanese Patent No. 2602460 is preferred, in which the airflow blown from the air nozzle and the spinning solution flow extruded from the spinning solution supply nozzle are parallel flows, and the parallel airflow is sufficiently rectified to contact the spinning solution.

[0106] During spinning, it is preferable to first form fully extended fibers from the spinning solution under conditions that suppress moisture evaporation and decomposition of the spinning solution, and then rapidly dry the fibers. Therefore, it is preferable to change the atmosphere from a state that suppresses moisture evaporation to a state that promotes moisture evaporation during the process of fiber formation from the spinning solution and arrival at the fiber collector.

[0107] The alumina / silica-based fiber precursor is captured by a fiber trap. The fiber trap is an annular belt made of metal mesh arranged at approximately right angles to the spinning airflow. The annular belt is rotated so that the spinning airflow containing the alumina / silica-based fiber precursor collides with it. This results in a continuous sheet-like thin layer of the alumina / silica-based fiber precursor.

[0108] The preferred weight per unit area of ​​the thin film is 10 g / m². 2 ~200g / m 2 The preferred value is 30g / m 2 ~100g / m 2Left and right, but not limited to that.

[0109] The aforementioned thin sheets can be further stacked. Specifically, for example, the thin sheets are continuously pulled out and fed to a folding device, folded to a predetermined width, and stacked. At this time, the thin sheets are continuously moved in a direction perpendicular to the folding direction. Thus, a stacked sheet is obtained. By stacking the thin sheets in this way, the weight per unit area (unit area weight) of the stacked sheet becomes uniform throughout the entire sheet. As the aforementioned folding device, the folding device described in Japanese Patent Application Publication No. 2000-80547 can be used.

[0110] The laminated sheet is formed by stacking thin sheets, preferably 5 or more, more preferably 8 or more, and particularly preferably 10 to 80 layers. However, the number of layers is not limited to these.

[0111] <Needle Puncture Process>

[0112] The laminated sheets obtained through the spinning process are subjected to a needle-punching process, in which barbed needles are pulled out / inserted. This yields a molded body of an alumina / silica-based fiber precursor. The needle-punching process can be performed on one side only or on both sides. It is preferred to perform it on both sides. During the needle-punching process, the multiple needle ratio is also adjusted by changing the conveying speed of the laminated sheets, etc. (multiple needle-punching process).

[0113] Preferably, the needle is withdrawn / inserted in a direction perpendicular to the surface of the laminate (the surface perpendicular to the thickness direction of the laminate). The needle penetrates deeper than the center of the laminate in the thickness direction. The needle can be inserted in a manner that penetrates the laminate in the thickness direction.

[0114] When needle punching is performed in this manner, at the point where the needle is withdrawn / inserted, at least a portion of the fibers extend through the needle in the approximate thickness direction. This creates needle marks on the surface of the molded body of the alumina / silica-based fiber precursor. Inside the molded body of the alumina / silica-based fiber precursor, a bundle of alumina / silica fibers extending in the approximate thickness direction is called a longitudinal filament. In multiple needle punches, fibers extending in the approximate thickness direction through other needles are added to the already formed longitudinal filaments, forming thicker longitudinal filaments.

[0115] Needle punching is performed to adjust the residual surface pressure after high-temperature cycling of alumina / silica fiber molded bodies and to suppress deformation during pressing by forming longitudinal filaments.

[0116] The stitches can penetrate through the molded body of the alumina / silica fiber precursor, or they can extend in a manner that penetrates from one pad surface without reaching another pad surface.

[0117] <Firing Process>

[0118] The holding member 1 of this disclosure is preferably an alumina / silica-based fiber molded body formed by firing an alumina / silica-based fiber precursor. The firing after needle punching is typically carried out at a temperature of 900°C or higher, preferably between 1000°C and 1300°C. If the firing temperature is 900°C or higher, sufficient crystallization occurs, resulting in alumina / silica-based fibers with excellent strength, which is therefore preferred. Furthermore, if the firing temperature is below 1300°C, excessive grain growth of the fiber crystals does not occur, resulting in alumina / silica-based fibers with moderate strength, which is also preferred.

[0119] <Punching Process>

[0120] After the firing process, the alumina / silica fiber molded body is die-cut to obtain the holding part 1.

[0121] [Uses of the gripping component]

[0122] The use of the gripper 1 disclosed herein is not particularly limited, and it is widely used in vehicles / machinery such as automobiles and construction vehicles where a catalyst carrier is housed within a metal casing. In particular, the gripper 1 is useful as a gripper for an exhaust purification device mounted on an automobile.

[0123] The inorganic fiber molded body constituting the gripper 1 of this disclosure does not contain adhesives, therefore, the catalyst carrier is less likely to detach from the gripper 1 during initial combustion. Furthermore, it eliminates odors caused by the combustion of organic adhesives and sensor malfunctions caused by adhesive components during combustion. Examples of adhesives include inorganic and organic adhesives. Examples of inorganic adhesives include silica sol and / or alumina sol. Examples of organic adhesives include synthetic rubbers such as acrylic rubber and nitrile rubber; water-soluble polymers such as carboxymethyl cellulose and polyvinyl alcohol; thermoplastic resins and thermosetting resins.

[0124] [Exhaust gas purification device]

[0125] The exhaust gas purification device includes: a catalyst carrier; a metal housing covering the outer side of the catalyst carrier; and a holding member disposed between the catalyst carrier and the housing. The exhaust gas purification device of this disclosure uses the holding member 1 of this disclosure as the holding member. The holding member 1 of this disclosure exhibits minimal deformation during pressing and high residual surface pressure after high-temperature cycling, thus ensuring good holding performance of the assembled catalyst carrier throughout its entire lifespan.

[0126] It should be noted that the composition of the exhaust purification device itself is not particularly limited, and this disclosure can be applied to various exhaust purification devices that have a catalyst carrier, a housing, and a catalyst carrier holding component.

[0127] Example

[0128] The following examples are for illustrative purposes only and are not intended to limit the scope of the invention in any way.

[0129] It should be noted that the methods for measuring and evaluating the various physical properties and characteristics of the inorganic fiber molded articles manufactured in the examples and comparative examples are as follows.

[0130] <Peeling Method>

[0131] A test piece with a width of 50 mm and a length of 150 mm is die-cut from an inorganic fiber molded body. A groove with a depth of 30 mm is formed in the center of the thickness of one end face 10e of the test piece 10. For example... Figure 2 As shown, the two ends formed by the groove are held by clamping fixtures 12 and placed in a tensile testing machine. The test piece 10 is torn into two pieces by stretching at a speed of 500 mm / min in the opposite direction perpendicular to the pad surface.

[0132] <Methods for determining needle density>

[0133] In this disclosure, when performing the above-described peeling method, the inorganic fiber molded body is cut into 50mm × 50mm squares as samples. Visible light is irradiated onto one side of the inorganic fiber molded body, and the number of light spots and longitudinal filaments obtained by transmission through the peeling surface is counted, thereby counting the total number of stitches per unit area. The number of stitches per unit area (1cm²) of the pad surface of the sintered inorganic fiber molded body is then counted. 2 The number of stitches is set as the stitch density.

[0134] <Multiple Needle Rate>

[0135] The multiple stitch rate is calculated using Formula 1 above. Here, the measured stitch density is the actual value obtained using the stitch density measurement method described above. The theoretical stitch density is the theoretical value of the stitch density calculated assuming no multiple stitches.

[0136] <Number of effective longitudinal threads>

[0137] In this disclosure, when implementing the above-described peeling method, all longitudinal filaments F protruding from the two peeling surfaces (one peeling surface 10a and the other peeling surface 10b) in each unit area (50mm × 50mm) are removed. Figure 3Longitudinal filaments with a diameter of 100µm or more and a protrusion length of 2mm or more are defined as valid longitudinal filaments, and their number is counted. It should be noted that the unit area (50mm×50mm) for measuring various values ​​related to longitudinal filaments is defined as any area that avoids the portion of the test piece 10 (150mm×50mm) where a 30mm deep groove is formed in the center of the thickness.

[0138] <Total volume V of effective longitudinal fibers>

[0139] After implementing the above-mentioned stripping method, all longitudinal filaments F protruding from the two stripping surfaces (one stripping surface 10a and the other stripping surface 10b) in each unit area (50mm×50mm) are removed. Figure 3 Longitudinal filaments with a diameter of 100µm or more and a protrusion length of 2mm or more are defined as effective longitudinal filaments within this range. Their number, diameter, and length are measured to determine the total volume of the effective longitudinal filaments. The diameter, length, and number of the aforementioned effective longitudinal filaments are determined by observing the peeling surface using a digital microscope (KEYENCE VHX-5000, 10x magnification).

[0140] <Average volume of effective longitudinal fibers for each stitch>

[0141] The average volume of the effective longitudinal fibers for each stitch is calculated as V / n, which is the sum of the volumes of all effective longitudinal fibers present on the two peeling surfaces (one peeling surface and the other peeling surface) per unit area (50mm×50mm) when the peeling method is performed, divided by the number of stitches per unit area n.

[0142] Average volume of each effective longitudinal fiber.

[0143] The average volume of each effective longitudinal filament is obtained by dividing the total volume V by the number of effective longitudinal filaments N.

[0144] <Amount of organic binder>

[0145] The amount of organic binder is determined by the ratio of the weight of the organic binder to the weight of the inorganic fiber molded body (the total weight of inorganic fiber + organic binder).

[0146] <Hot Pull-out Test>

[0147] The GBD of the pressed inorganic fiber molded body is 0.36 g / cm³. 3The catalyst support and SUS tube dimensions were selected using a specific method. An assembly formed by winding inorganic fibers onto the catalyst support was pressed into the SUS tube. While pushing the catalyst support at a speed of 0.05 mm / min, the catalyst support was heated at a rate of 10 °C / min after 40 minutes. The average pull-out load at room temperature and the minimum pull-out load during heating were recorded from 30 to 40 minutes after the start of the test. The load reduction rate was calculated using Formula 2 below. The pull-out load was measured by a load sensor.

[0148] [Formula 2]

[0149] Load reduction rate (%) = (1 - (Minimum value of pull-out load during heating / Average value of pull-out load at room temperature)) 100……Equation 2

[0150] <Room Temperature Indentation Test>

[0151] GBD=0.3

[0152] In the room temperature indentation test, the GBD of the indented inorganic fiber molded body was set to 0.30 g / cm³. 3 The catalyst support and SUS tube dimensions were selected using a specific method. When winding the inorganic fiber molded body around the catalyst support, the lower end of the inorganic fiber molded body was 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 was measured at five circumferential points on both the outer circumferential side (A) and the inner circumferential side (B). Furthermore, the distance from the lower end of the inorganic fiber molded body to the lower end of the catalyst support was measured at five circumferential points on the inner circumferential side (C).

[0153] After measurement, a clamp was used to press the catalyst support wrapped with the inorganic fiber molded body into the SUS tube. After pressing, the distance from the top of the inorganic fiber molded body to the top of the catalyst support was measured again at five circumferential points on both the outer circumferential side (A') and the inner circumferential side (B'). In addition, the distance from the bottom of the inorganic fiber molded body to the bottom of the catalyst support was measured at five points on the inner circumferential side (C').

[0154] This is just an example. Figure 5 (A) is a partial schematic cross-sectional view of the assembly 3 before the pressing of the holding member 1, which is made of inorganic fiber molded body, wrapped around the catalyst carrier 2. Figure 5 (B) is a partial schematic cross-sectional view of assembly 3 after pressing.

[0155] Use the following formula to evaluate the measurement results.

[0156] Deformation amount = (B' - A') - (BA)

[0157] Elongation = (B' - C') - (BC)

[0158] Total deformation = Deformation + Elongation

[0159] <Effective Area>

[0160] The effective area is calculated by multiplying the effective height by the length of the gripping component. Figure 5 Based on example (B), the effective height ( Figure 5 In (B), reference numeral H) refers to the distance from the upper end of the inner circumferential side of the holding member 1 (the side in contact with the catalyst carrier 2) to the lower end of the outer circumferential side of the holding member 1 (the side in contact with the shell) after the assembly 3 is pressed into the shell. Furthermore, the length of the holding member 1 is the circumferential length of the inner circumferential surface of the holding member 1 in the state of being assembled.

[0161] <Room Temperature Indentation Test>

[0162] GBD=0.4

[0163] The above-described room temperature indentation test was performed at GBD=0.4.

[0164] <Method for determining residual surface pressure>

[0165] The residual surface pressure is determined by the following method.

[0166] The inorganic fiber molded body was compressed for 30 minutes at GBD (bulk density) = 0.30. The upper and lower plates were then heated to 600°C. This process was repeated 1000 times, with GBD = 0.27 for opening and GBD = 0.30 for compression. The surface pressure values ​​at the first opening (GBD = 0.27) and the 1000th opening (GBD = 0.27) were then measured.

[0167] Set the surface pressure value (kPa) at the 1000th opening as the residual surface pressure (surface pressure after high-temperature cycling).

[0168] [Example 1]

[0169] In an aqueous solution of alkaline aluminum chloride (aluminum content 165 g / L, Al / Cl = 1.8 (atomic ratio)), silica sol was added so that the final composition of the alumina fiber was Al2O3:SiO2 = 72:28 (weight ratio). After further adding polyvinyl alcohol, the solution was concentrated to prepare a spinning solution with a viscosity of 70 poise (25°C) and an alumina / silica content of about 35% by weight.

[0170] The spinning solution described above is spun using a jet spinning method. A spinning nozzle with the same structure as the spinning nozzle described in Figure 6 of Japanese Patent No. 2602460 is used as the spinning nozzle. Furthermore, during fiber collection, a fiber collector with the following structure is used: an annular belt made of metal mesh is arranged at approximately a right angle to the spinning airflow, and the spinning airflow containing the alumina / silica-based fiber precursor collides with the annular belt while the annular belt is rotated. This allows the alumina / silica-based fiber precursor to be recovered as a continuous sheet (thin sheet).

[0171] After a thin sheet is coated with a friction-reducing agent by spraying, it is continuously pulled out and fed to a folding device. While being folded to a specified width and stacked, it is continuously moved in a direction perpendicular to the folding direction, thereby producing a laminated sheet. The folding device described above uses a folding device with the same structure as the folding device described in Japanese Patent Application Publication No. 2000-80547.

[0172] In the needle punching process, needle punching machinery is used to make the sintered alumina / silica fiber molded body have a needle density of 10.6 dozen / cm. 2 The laminated sheets were needle-punched using a multi-needle method with a needle rate of 58%. This yielded a molded body of the alumina / silica fiber precursor.

[0173] Then, the molded body of the alumina / silica fiber precursor was fired at 1200°C to obtain a product with a unit area weight of 1200 g / m². 2 The inorganic fiber molded body is composed of crystalline alumina / silica fibers. Firing is performed in a gas-fired furnace, with the temperature increased to 1200°C at a rate of 5°C / min, held at 1200°C for 30 minutes, and then allowed to cool naturally. This inorganic fiber molded body is not impregnated with a binder.

[0174] It should be noted that the composition ratio of the crystalline alumina / silica fiber is alumina / silica = 72 / 28 (by weight), and the average fiber diameter (average of 100 fibers) of the crystalline alumina / silica fiber, as determined by microscopic observation of the inorganic fiber molded body, is 5.5µm.

[0175] The measurement results for the obtained inorganic fiber molded bodies are shown in Table 1.

[0176] [Example 2]

[0177] To achieve a unit area weight of 1400g / m² 2 Stitch density 10.0 dozen / cm 2 Acupuncture was performed using a multi-needle rate of 50%, otherwise, it was set up the same as in Example 1.

[0178] [Example 3]

[0179] To achieve a unit area weight of 1700g / m² 2 Stitch density 14.7 dozen / cm 2 Acupuncture was performed using a multiple needle rate of 45%, otherwise, it was set up the same as in Example 1.

[0180] [Example 4]

[0181] To achieve a unit area weight of 2000g / m² 2 Stitch density 12.4 dozen / cm 2 Acupuncture was performed using a multi-needle rate of 50%, otherwise, it was set up the same as in Example 1.

[0182] [Comparative Example 1]

[0183] Stitch density 14.1 dozen / cm 2 Needling was performed with a multi-needle ratio of 40%, and an organic binder was added at a ratio of 3.8% relative to the weight of the inorganic fiber molded body. Otherwise, it was set to be the same as in Example 1.

[0184] [Comparative Example 2]

[0185] To achieve a stitch density of 4.8 dozen / cm 2 Acupuncture was performed using a multiple needle rate of 10%, otherwise, it was set up the same as in Example 1.

[0186] [Comparative Example 3]

[0187] The weight per unit area is 1700g / m² 2 The stitch density is 5.3 dozen / cm. 2 The acupuncture was performed with a multiple needle rate of 2%, otherwise it was set the same as in Example 1.

[0188] [Comparative Example 4]

[0189] The weight per unit area is 1700g / m² 2 The stitch density is 25.9 dozen / cm. 2 The acupuncture was performed with a multiple needle rate of 9%, otherwise it was set the same as in Example 1.

[0190] [Comparative Example 5]

[0191] The weight per unit area is 1400g / m² 2 The stitch density is 18.8 dozen / cm. 2 The acupuncture was performed with a multiple needle rate of 3%, otherwise it was set the same as in Example 1.

[0192] [Comparative Example 6]

[0193] The weight per unit area is 1275g / m² 2 The stitch density is 39.7 dozen / cm². 2 Acupuncture was performed with a multiple needle rate of 0%, otherwise, it was the same as in Example 1.

[0194] [Table 1]

[0195] As shown in Table 1, the inorganic fiber molded bodies of Examples 1 to 4 have a moderate stitch density and a moderate number of effective longitudinal filaments, resulting in a small overall deformation during the pressing test at room temperature, maintaining the residual surface pressure after high-temperature cycling, and a small load reduction rate during the hot pull-out test.

[0196] The inorganic fiber molded body of Comparative Example 1 contains an organic binder, resulting in a large load reduction rate during the hot pull-out test. When the inorganic fiber molded body of Comparative Example 1 is used in automobiles, there is a high possibility of catalyst carrier detachment during initial combustion.

[0197] The needle density of the inorganic fiber molded body in Comparative Example 2 is lower than that of the inorganic fiber molded body of Example 1 with the same unit area weight, and the number of effective longitudinal filaments is also less than that of the inorganic fiber molded body of Example 1 with the same unit area weight. Therefore, the overall deformation in the room temperature indentation test is greater. The greater the GBD, the greater the overall deformation. If the overall deformation is large, the effective area decreases, and therefore the force holding the catalyst support decreases. Therefore, when using the inorganic fiber molded body of Comparative Example 2, the possibility of catalyst support detachment is high.

[0198] The needle density of the inorganic fiber molded body in Comparative Example 3 is lower than that of the inorganic fiber molded body of Example 3 with the same unit area weight, and the number of effective longitudinal filaments is also less than that of the inorganic fiber molded body of Example 3 with the same unit area weight. Therefore, the overall deformation in the room temperature indentation test is greater. If the overall deformation is greater, the effective area is reduced, and thus the force holding the catalyst support is reduced. Therefore, when using the inorganic fiber molded body of Comparative Example 3, the possibility of catalyst support detachment is high.

[0199] The needle density of the inorganic fiber molded body in Comparative Example 4 is higher than that of the inorganic fiber molded body in Example 3 with the same unit area weight, and therefore the residual surface pressure is lower. Because of the lower residual surface pressure, the inorganic fiber molded body of Comparative Example 4 has a higher likelihood of shedding during long-term use.

[0200] The inorganic fiber molded body of Comparative Example 5 has a greater number of effective longitudinal filaments than the inorganic fiber molded body of Example 2 with the same unit area weight, and a higher stitch density than the inorganic fiber molded body of Example 2 with the same unit area weight, resulting in lower residual surface pressure. Because of the lower residual surface pressure, the inorganic fiber molded body of Comparative Example 5 has a higher likelihood of shedding during long-term use.

[0201] The inorganic fiber molded body of Comparative Example 6 has a greater number of effective longitudinal filaments than the inorganic fiber molded body of Example 1 with the same weight per unit area, and a higher stitch density than the inorganic fiber molded body of Example 1 with the same weight per unit area, resulting in lower residual surface pressure. Because of the lower residual surface pressure, the inorganic fiber molded body of Comparative Example 6 has a higher likelihood of shedding during long-term use.

[0202] Explanation of reference numerals in the attached figures

[0203] 2: Catalyst carrier; 3: Holding component for exhaust gas purification device; 6: Housing; 8: Exhaust gas purification device; 10: Test piece; 10e: End face; 12: Clamping fixture.

Claims

1. A holding member for an exhaust purification device, wherein the holding member for the exhaust purification device is provided with an inorganic fiber molded body composed of inorganic fibers, and does not contain a binder, the inorganic fiber molded body has a needle trace extending in a thickness direction, and a longitudinal filament formed of the inorganic fibers extending in the thickness direction is present in the needle trace, Stitch density 8.0 stitches / cm 2 ~ 18.0 stitches / cm 2 , The number of effective longitudinal threads is 2.8 threads / cm 2 ~ 6.0 threads / cm 2 , The average volume of each effective longitudinal thread is 1.5 mm 3 / strand ~ 4.0 mm 3 / strand, the effective longitudinal filament indicates a longitudinal filament having a diameter of 100 µm or more and a protruding length of 2 mm or more among all longitudinal filaments protruding from one peeling surface and another peeling surface in a range of 50 mm x 50 mm when a peeling method described below is implemented, the peeling method: a test piece having a width of 50 mm and a length of 150 mm is die-cut from the inorganic fiber molded body; then, a 30 mm deep cut groove is made in the center of the thickness of one end surface of the test piece, both ends of the test piece formed by the cut groove are supported to a clamping jig, and then, are set to a tensile testing machine; the both ends of the test piece are stretched in opposite thickness directions at a speed of 500 mm / min to tear into two pieces.

2. A holding member for an exhaust purification device, wherein the holding member for the exhaust purification device is provided with an inorganic fiber molded body composed of inorganic fibers, and does not contain a binder, the inorganic fiber molded body has a needle trace extending in a thickness direction, and a longitudinal filament formed of the inorganic fibers extending in the thickness direction is present in the needle trace, Stitch density 8.0 stitches / cm 2 ~ 18.0 stitches / cm 2 , The number of effective longitudinal threads is 2.8 threads / cm 2 ~ 6.0 threads / cm 2 , a residual surface pressure after a high temperature cycle is 30 kPa or more, the effective longitudinal filament indicates a longitudinal filament having a diameter of 100 µm or more and a protruding length of 2 mm or more among all longitudinal filaments protruding from one peeling surface and another peeling surface in a range of 50 mm x 50 mm when a peeling method described below is implemented, the peeling method: a test piece having a width of 50 mm and a length of 150 mm is die-cut from the inorganic fiber molded body; then, a 30 mm deep cut groove is made in the center of the thickness of one end surface of the test piece, both ends of the test piece formed by the cut groove are supported to a clamping jig, and then, are set to a tensile testing machine; the both ends of the test piece are stretched in opposite thickness directions at a speed of 500 mm / min to tear into two pieces.

3. The holding member for the exhaust purification device according to claim 1 or 2, wherein The total volume of the effective longitudinal filaments is 6.5 mm 3 / cm 2 ~ 10.0 mm 3 / cm 2 .

4. The holding member for the exhaust purification device according to claim 1 or 2, wherein The unit area weight of the holding member of the exhaust purification device is 1000 g / m 2 ~2000 g / m 2 .

5. The holding member for the exhaust purification device according to claim 1, wherein a residual surface pressure after a high temperature cycle of the holding member for the exhaust purification device is 30 kPa or more.

6. An exhaust purification device provided with: a catalyst carrier; a housing covering an outer side of the catalyst carrier; and a holding member for the exhaust purification device according to claim 1 or 2, which is arranged between the catalyst carrier and the housing.

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