JP2011208520A - Holding member for catalytic converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the mountability of a protective film on a catalyst carrier by providing ductility to the protective film in a holding member on which the protective film is formed.SOLUTION: This holding member is used for a catalytic converter including the catalyst carrier, a metal casing for storing the catalyst carrier, and the holding member which is wrapped around the catalyst carrier and interposed in the gap between the catalyst carrier and the metal casing. The protective film having projections or wrinkles is joined to the surface of an inorganic fiber base on the metal casing side.

Description

  The present invention provides a catalyst carrier incorporated in a catalytic converter for removing particulates, carbon monoxide, hydrocarbons, nitrogen oxides and the like contained in exhaust gas discharged from an internal combustion engine such as a gasoline engine or a diesel engine. The present invention relates to a holding material for a catalytic converter (hereinafter also simply referred to as “holding material”) for holding in a casing.

  As is well known, vehicles such as automobiles are equipped with a catalytic converter for exhaust gas purification in order to remove harmful components such as carbon monoxide, hydrocarbons and nitrogen oxides contained in the exhaust gas of the engine. Yes. FIG. 12 is a cross-sectional view schematically showing an example of a catalytic converter. In this catalytic converter 10, an introduction pipe 16 into which exhaust gas discharged from an internal combustion engine is introduced is connected to one end portion of a metal casing 11, and exhaust gas that has passed through the catalyst carrier 12 is connected to the other end portion. A discharge pipe 17 for discharging to the outside is provided. Further, inside the metal casing 11, a catalyst carrier 12 is installed via a holding material 13.

  Since the catalyst carrier 12 is generally a cylindrical honeycomb-shaped body made of, for example, cordierite or the like, a noble metal catalyst or the like is supported on the holding material 13. A function of safely holding the catalyst carrier 12 so that the metal carrier 12 does not collide with the metal casing 11 and is damaged, and a function of sealing so that unpurified exhaust gas does not leak from the gap between the catalyst carrier 12 and the metal casing 11. It is necessary to combine these functions. Therefore, currently, inorganic fibers such as alumina fibers, mullite fibers, or other ceramic fibers are formed into a mat having a predetermined thickness using an organic binder. Moreover, the shape has shown the planar shape shown to FIG. 13 (A), the convex part 42 is formed in the end of the flat plate-shaped main-body part 41, and the convex part 42 can be fitted in the other end. A concave portion 43 having an arbitrary shape is formed. Then, as shown in FIG. 13B, the main body 41 is wound around the outer peripheral surface of the catalyst carrier 12, and the convex portion 42 and the concave portion 43 are engaged with each other to be wound around the catalyst carrier 12.

  The catalyst carrier 12 is press-fitted (canned) into the metal casing 11 in a state in which the holding material 13 is wound, so that the catalytic converter 10 is obtained. In order to improve the workability of this canning, a protective film 50 such as a film, tape, non-woven fabric, or resin coating is added to the casing side surface (outer peripheral surface) of the holding material 13 to reduce the frictional resistance ( (See Patent Documents 1 and 2).

JP 2001-32710 A JP-A-8-61054

  The holding material 13 formed with such a protective film 50 is obtained by forming the protective film 50 on one surface of a flat mat made of inorganic fibers as shown in FIG. In order to wind it around, it is necessary to bend so that the convex part 42 and the concave part 43 engage with the protective film 50 on the outside. For this reason, the protective film 50 is stretched in the left-right direction in the figure, but in the case of a film, tape, or nonwoven fabric, it is difficult to stretch because it is a single continuous body, and in some cases, it may break. In addition, when the resin coating is applied, when the holding material 13 is bent, a large number of cracks may occur so as to be orthogonal to the bending direction (along the axial direction of the catalyst carrier 12).

  The present invention has been made in view of such a situation, and an object of the present invention is to impart stretchability to the protective film in the holding material on which the protective film is formed, and to improve the mounting property to the catalyst carrier. .

In order to achieve the above object, the present invention provides the following holding material for a catalytic converter.
(1) Holding used for a catalytic converter comprising a catalyst carrier, a metal casing that houses the catalyst carrier, and a holding member that is wound around the catalyst carrier and interposed in a gap between the catalyst carrier and the metal casing. A holding material for a catalytic converter, characterized in that a protective film having protrusions or wrinkles is joined to the surface of the inorganic fiber base material on the metal casing side.
(2) The holding material for a catalytic converter as described in (1) above, wherein the basis weight of the protective film is 1.05 to 2 times the basis weight before the protrusions or wrinkles are formed.
(3) The holding material for a catalytic converter according to the above (1) or (2), wherein the protective film has an opening.
(4) The holding material for a catalytic converter according to the above (3), wherein the opening ratio in the protective film is 10 to 45%.
(5) For the catalyst carrier having a flat cross-sectional shape, and a protective film is formed only on a portion covering the portion where the curvature of the cross-sectional shape of the catalyst carrier is maximum. (4) The holding material for a catalytic converter according to any one of (4).
(6) Basis weight of protective film is 1 to 30 g / m ² , The catalytic converter holding material according to any one of (1) to (5) above.
(7) The catalytic converter holding material according to any one of (1) to (6), wherein the protective film is made of at least one of polyethylene terephthalate, polyethylene, polypropylene, or cellulose.
(8) The holding material for a catalytic converter according to any one of (1) to (7) above, wherein the organic component of the entire holding material is 5% by mass or less of the total amount of the holding material.

  Since the holding material of the present invention has a protective film, it has excellent canning properties, and since the protective film has excellent stretchability, it also has excellent mounting properties to the catalyst carrier.

It is a schematic diagram which expands and shows the protective film surface of the holding | maintenance material for catalytic converters of this invention, and is the example which formed the protrusion in the protective film. It is a schematic diagram which expands and shows the protective film surface of the holding | maintenance material for catalytic converters of this invention, and is the example which formed the wrinkles in the protective film. It is a figure which shows the example which formed opening in the protective film. It is a top view which shows the other example of an opening pattern. It is a top view which shows the other example of an opening pattern. It is a top view which shows the other example of an opening pattern. It is a top view which shows the other example of an opening pattern. It is a figure which shows the state which wound the holding | maintenance material of this invention around the catalyst support of a cross-sectional flat shape. It is the perspective view which expand | deployed the holding | maintenance material of FIG. 8 on the plane. It is a figure which shows the state which wound the holding | maintenance material of this invention on the other catalyst support | carrier of the cross-sectional flat return shape. It is a figure which shows the state which wound the holding | maintenance material of this invention on the other catalyst support | carrier of the cross-sectional flat shape. It is sectional drawing which shows an example of a catalytic converter. (A) The top view of the conventional holding | maintenance material for catalytic converters, (B) It is a perspective view which shows the state wound around the catalyst support | carrier.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a perspective view showing a part of the holding material 13 of the present invention. The overall shape of the holding material 13 is one side of a base material 45 made of an inorganic fiber flat mat as shown in FIG. The protective film 50A is bonded to the surface. Further, as shown in FIGS. 13 (A) and 13 (B), a convex portion 42 and a concave portion 43 are formed at both ends in the longitudinal direction of the main body portion 41, and both are engaged when wound around the catalyst carrier 12. (Both not shown).

  However, in the present invention, the protrusion 51 as shown in FIG. 1 or the flange 52 as shown in FIG. 2 is formed on the entire surface of the protective film 50A.

  In FIG. 1, the shape of the protrusion 51 is not limited, and may be a hemispherical shape, a conical shape, or a columnar shape in addition to the cross-sectional waveform as illustrated. The dimensions of the protrusions 51 are not limited, but considering the stretchability, the width or diameter L of the skirt portion is preferably 0.05 to 1 mm, the pitch (apex distance) P is preferably 0.01 to 1 mm, and 1 to 0.7 mm is more preferable. Further, the protrusions 51 may be regularly formed in a lattice shape or may be randomly formed. Furthermore, all the protrusions 51 may have the same dimensions (height H and width L) or may be different from each other. The protrusion 51 can be formed by pressing a pressing plate having the protrusion. Since the protrusion 51 can be extended in any horizontal direction and has no anisotropy unlike the flange 52 described later, it has excellent workability.

  In FIG. 2, the ridge 52 may be formed so as to extend perpendicularly (shown as the vertical direction in the drawing) to the direction (shown as the drawing direction in the drawing) when the holding material 13 is bent. As shown in the figure (A), you may form in the full width of the holding | maintenance material 13, and as shown in the figure (B), you may form intermittently and further randomly. In addition, the cross-sectional shape of the flange 52 may be a triangle or the like in addition to the waveform, and the size is not limited. Furthermore, the ridgeline K may be a straight line or may be curved. Note that the ridge 52 can be formed by ordinary ridge processing such as that used in the manufacture of crepe paper.

  Thus, in the protective film 50A in which the protrusions 51 and the flanges 52 are formed, the surface area becomes large, so that the basis weight before the protrusions 51 and the flanges 52 are formed is larger. The increase in basis weight is preferably 5% (1.05 times) to 100% (2 times), preferably 5% (1.05 times) to 30% (1.3 times) in consideration of stretchability. More preferred. The degree of stretching of the protective film 50A increases as the basis weight increases, but when the basis weight exceeds 100%, the excess is obtained by subtracting the stretching in the state where the holding material 13 is wound around the catalyst carrier 12. The protective film 50A remains so as to wave, and becomes a resistance during canning. Further, as will be described later, it is preferable to perform heat fusion as a method of joining the protective film 50A to the base material 45. However, as the basis weight increases, heat fusion is performed with the protrusions 51 and the ridges 52 remaining. It becomes difficult to do.

Further, as the basis weight increases, the organic component as the whole holding material also increases. In the catalytic converter, the catalyst carrier 12 is heated to near 1000 ° C. in order to increase the purification efficiency, but the organic components are easily decomposed and burned to generate CO ₂ , CO, and various organic gases. It occurs in large quantities in the early stage of converter operation. Exhaust gas regulations are becoming stricter, and a large amount of CO ₂ derived from organic components is generated, which is not preferable. Further, recently, electronic control of the engine has been advanced. However, if there is CO ₂ unrelated to the original exhaust gas, the exhaust system sensors are erroneously operated to adversely affect the electronic control of the engine. In order to prevent such problems, manufacturers are working to remove organic components by burning them before shipping. Therefore, it is preferable to suppress an increase in basis weight of the protective film 50A.

  Thus, by forming the protrusions 51 and the flanges 52 on the protective film 50A, the protective film 50A extends in the curved direction when the holding material 13 is wound around the catalyst carrier (see FIG. 13B). This makes it easier to install.

  The material of the protective film 50A may be a conventionally known material, for example, polyethylene, ethylene-vinyl acetate copolymer, polypropylene, polyvinyl chloride, polyvinyl acetate, polyvinyl alcohol, polyamide, polystyrene, polycarbonate, polyethylene terephthalate. And a film or non-woven fabric made of polybutylene terephthalate or the like. Moreover, cellulose may be sufficient. Among these, polyethylene terephthalate, polyethylene, polypropylene, and cellulose nonwoven fabrics are preferred because they are available at low cost, are easy to stretch, and have strength.

  The thickness of the protective film 50A is not limited. However, if the thickness is too thin, the film strength becomes low, and the film tends to break during canning or after being wound around the catalyst carrier 12. Moreover, when it becomes too thick, it will become difficult to extend | stretch and also an organic component will also increase. The film strength is preferably 0.5 N / 30 mm or more in terms of tensile strength, and more preferably 2 N / 30 mm or more. The tensile strength is measured according to JIS P 8813.

  Further, an opening may be formed in the protective film 50A. By doing so, the organic component can be further reduced. The opening formation pattern is not limited, but for example, the openings 60 may be formed at equal intervals as shown in FIG. 3, or may be formed in a staggered pattern as shown in FIG. Moreover, although illustration is abbreviate | omitted, you may form at random. Further, as shown in FIG. 5, circles having different sizes may be combined.

  The opening 60 may be elliptical as shown in FIG. The major axis of the ellipse may be formed along the longitudinal direction (left and right direction on the paper surface) of the holding member 13 as illustrated, or may be formed to be orthogonal to the longitudinal direction (up and down direction on the paper surface). However, it may be formed along the diagonal direction in the longitudinal direction. Since the holding member 13 is press-fitted in the width direction, the holding member 13 is easily press-fitted by forming the opening 60 so that the major axis coincides with the width direction of the holding member 13. On the other hand, by forming the opening 60 so that the major axis of the ellipse coincides with the longitudinal direction of the holding material 13, it becomes easy to bend when wound around the catalyst carrier 12. Further, as shown in the figure, ellipses having different sizes may be combined.

  The opening 60 preferably has a minimum length, that is, a diameter in the case of a circle as shown in FIGS. 3 to 5 and a minor axis of 5 mm or more in the case of an ellipse as shown in FIG. More preferably, it is 10-15 mm. As shown in FIGS. 5 and 6, when openings 60 having different sizes are mixed, the diameter or minor axis of the smallest opening is set to 10 mm or more. Since the periphery of the opening 60 becomes resistance during press-fitting, the smaller the opening diameter, the more openings 60 must be formed, and the frictional resistance during press-fitting increases. On the other hand, if the opening diameter exceeds 30 mm, a large amount of the base material 45 is exposed and the frictional resistance during press-fitting increases.

  As shown in FIG. 3, the distance D between adjacent openings 60 is preferably 3 mm or more, and more preferably greater than 5 mm and 15 mm or less. Since the protective film 50A between the openings becomes narrower as the interval between the adjacent openings 60 becomes narrower, the protective film 50A is likely to break during press-fitting. Further, since the protective film 50A between the openings becomes wider as the interval between the openings 60 becomes wider, the breakage of the protective film 50A at the time of press-fitting can be suppressed, but the effect of providing the openings 60 decreases.

  As shown in FIG. 7, it is preferable not to form the opening 60 in the peripheral region 47 of the convex portion 42 of the main body 41 of the holding member 13 and the peripheral region 48 of the concave portion 43. As shown in FIG. 13 (B), the convex portion 42 and the concave portion 43 are portions that are engaged when the holding material 13 is wound around the catalyst carrier 12, and if there is a step at the engagement end edge, the metal is pressed during press-fitting. It may get caught on the inner surface of the casing. Even if there is a step at the engagement end edge, the frictional resistance is reduced by the protective film 50A and it is easy to press-fit, but if the opening 60 is present, the base material 45 is exposed and the frictional resistance is increased accordingly. Therefore, by not forming the opening 60 only in the peripheral portions 47 and 48 of the convex portion 42 and the concave portion 43, the frictional resistance can be reduced as much as possible. Therefore, as the peripheral portions 47 and 48 become wider, the frictional resistance at the time of press-fitting can be reduced. However, since the effect of providing the opening 60 decreases, the width of the peripheral portions 47 and 48 is the dimension in the figure. It is preferable that a is 50 to 100% of the full width of the holding material, b is 5 to 9% of the full length of the holding material, c is 5 to 9% of the full length of the holding material, and d is 50 to 100% of the full width of the holding material.

  In any of the above cases, the opening ratio of the opening 60, that is, the ratio of the opening 60 in the total area of the protective film 50A is preferably 10 to 45%, and more preferably 20 to 35%. As the aperture ratio decreases, the effect of providing the opening 60 decreases although the decrease in the original function of the protective film is small. On the other hand, the larger the aperture ratio, the greater the decrease in the original function of the protective film. Further, the base material 45 is exposed, and the frictional resistance increases accordingly, resulting in poor canning performance. Therefore, the aperture ratio range is set by adjusting the size of the openings 60, the interval between the apertures, the combination of apertures having different sizes, the formation pattern, and the like.

The protective film 50A is preferably a basis weight of ^{1~30g / m 2, 1~10g / m} 2 from the viewpoint of reducing the organic components, and more preferably 1 to 5 g / ^{m 2.} The film thickness, the formation style of the protrusions 51 and the ridges 52, and the opening 60 are adjusted so as to have such a basis weight.

  In order to join the protective film 50A to the base material 45, an adhesive or a method of heat-sealing by hot pressing can be used. However, the method using an adhesive increases the organic content, and in the case where the adhesive is a non-woven fabric, the adhesive tends to protrude from the gap between the fibers, resulting in poor appearance.

  The base material 45 is not limited. For example, the base material 45 is made of a blanket obtained by wet-molding inorganic fibers and a small amount of an organic binder and then drying in a compressed state, and a needle-processed collection of inorganic fibers. A mat material such as an expansion mat obtained by wet molding a mat, an inorganic fiber, and an expansion material such as vermiculite can be used.

  There is no restriction on the overall shape of the base material 45. For example, as shown in FIG. 13A, a convex portion 42 can be formed at one end of the flat plate-like main body portion 41 and can be fitted to the convex portion 42 at the other end. It can be made the shape which formed the concave part 43 of various shapes. In addition, the shape of the convex part 42 and the recessed part 43 may be a triangle and a semicircle shape other than the rectangle shown in figure. Further, the number of the convex portions 42 and the concave portions 43 is not limited to one, and may be two or more.

As the inorganic fiber, various inorganic fibers conventionally used for holding materials can be used. For example, alumina fibers, mullite fibers, or other ceramic fibers can be used as appropriate. More specifically, as the alumina fiber, for example, Al ₂ O ₃ is preferably 90% by weight or more (the remainder is SiO ₂ minutes), and X-ray is preferably low crystallinity, An average fiber diameter of 3 to 10 μm and a wet volume of 300 cc / 5 g or more are preferable. As the mullite fiber, for example, a mullite composition having an Al ₂ O ₃ minute / SiO ₂ minute weight ratio of about 70/30 to 83/17 and having a low crystallinity in terms of X-ray is preferable. The average fiber diameter is preferably 3 to 10 μm and the wet volume is 300 cc / 5 g. Examples of other ceramic fibers include silica-alumina fibers, any of which may be conventionally used for holding materials. Moreover, you may mix | blend glass fiber, a silica fiber, rock wool, and a biosoluble inorganic fiber, and you may combine any 2 or more.

The wet volume is calculated by the following method.
1) Weigh 5 g of dried fiber material with a scale having an accuracy of two decimal places or more.
2) Place the weighed fiber material into a 500 ml glass beaker.
3) About 400 ml of distilled water having a temperature of 20 to 25 ° C. is placed in the glass beaker of 2), and carefully stirred and dispersed using a stirrer so as not to cut the fiber material. An ultrasonic cleaner may be used for this dispersion.
4) Transfer the contents of the glass beaker of 3) to a 1000 ml graduated cylinder and add distilled water to a scale of 1000 cc.
5) Close the mouth of the graduated cylinder of 4) with your hands, and stir it upside down, taking care not to leak water. This is repeated a total of 10 times.
6) After the stirring is stopped, the mixture is allowed to stand at room temperature, and the fiber sedimentation volume after 30 minutes is visually measured.
7) The above operation is performed on three samples, and the average value is taken as the measured value.

  The organic binder may be a known one, and rubbers, water-soluble organic polymer compounds, thermoplastic resins, thermosetting resins, and the like can be used. Specifically, examples of rubbers include a copolymer of n-butyl acrylate and acrylonitrile, a copolymer of ethyl acrylate and acrylonitrile, a copolymer of butadiene and acrylonitrile, and butadiene rubber. Examples of the water-soluble organic polymer compound include carboxymethyl cellulose and polyvinyl alcohol. Examples of thermoplastic resins include homopolymers and copolymers such as acrylic acid, acrylic ester, acrylamide, acrylonitrile, methacrylic acid, methacrylic ester, acrylonitrile / styrene copolymer, acrylonitrile / butadiene / styrene copolymer Etc. Examples of the thermosetting resin include a bisphenol type epoxy resin and a novolac type epoxy resin. Further, any two or more of these organic binders may be used in combination.

  Moreover, it is also possible to mix | blend a small amount of organic fibers, such as a pulp, with the base material 45 as an organic binder. The thinner and longer the organic fiber, the higher the binding force, and highly fibrillated cellulose and cellulose nanofiber are preferred. Specifically, the fiber diameter is preferably 0.01 to 50 μm, the fiber length is preferably 1 to 5000 μm, the fiber diameter is preferably 0.02 to 1 μm, and the fiber length is more preferably 10 to 1000 μm.

  These organic binders can be used in combination of two or more. Although there will be no restriction | limiting if the usage-amount of an organic binder is the quantity which can bind an inorganic fiber, It is 0.1-10 mass parts with respect to 100 mass parts of inorganic fibers. When the organic binder is less than 0.1 parts by mass, the binding force is insufficient, and when it exceeds 10 parts by mass, there is a possibility that the exhaust gas regulations may be exceeded when disappearing. A preferable amount of the organic organic binder is 0.2 to 6 parts by mass, and a more preferable amount is 0.2 to 3 parts by mass.

  An organic binder and an inorganic binder may be used in combination. According to the combined use of the organic binder and the inorganic binder, in order to avoid the above-mentioned problems caused by the volatilization of the organic component at the time of use, the inorganic fibers are bound well even when the amount of the organic binder used is reduced. In addition, it is possible to provide a holding material for a catalytic converter that can maintain the same thickness as the conventional one. Such inorganic binders may be known ones, and examples thereof include glass frit, colloidal silica, alumina sol, sodium silicate, titania sol, lithium silicate, water glass, and bentonite. In addition, these inorganic binders can also be used in combination of 2 or more types. Although the usage-amount of an inorganic binder will not be restrict | limited if it is the quantity which can bind an inorganic fiber, it is 0.1-10 mass parts with respect to 100 mass parts of inorganic fibers. If the inorganic binder is less than 0.1 parts by mass, the binding force is insufficient, and if it exceeds 5 parts by mass, the amount of inorganic fibers is relatively reduced, and the holding performance and sealing performance required as a holding material cannot be obtained. A preferable amount of the inorganic binder is 0.2 to 6 parts by mass, and a more preferable amount is 0.2 to less than 4 parts by mass.

  The smaller the total organic content of the holding material, that is, the total of the base material 45 and the protective film 50A, the better. Specifically, the organic content is preferably 5% by mass or less of the total amount of the holding material, more preferably 3% by mass or less, particularly preferably 2% by mass or less, 1.5% by mass or less, 1.0% by mass. Hereinafter, it may be 0.5% by mass or less. Therefore, in the base material 45, it is preferable to keep the organic binder and the organic fiber in a very small amount so that the compressed state can be maintained.

  In the above, the case where the catalyst single body has a circular cross section has been described. However, the catalyst carrier may have a flat cross section such as an ellipse or a track shape. In that case, when the holding material 13 is mounted, the protrusions 51 and the flanges 52 may be formed only in the portion where the holding material 13 is greatly curved.

  For example, FIG. 8 shows a state in which the holding material 13 is wound around the catalyst carrier 12 having an elliptical cross section. The holding member 13 is engaged with the convex portion 42 and the concave portion 43 immediately above one intersection C1 with the minor axis Y of the surface of the catalyst carrier 12, and on both sides of the intersection C2 with the major axis X of the surface of the catalyst carrier 12. Thus, it is greatly curved over a predetermined length. Therefore, in the protective film 50A of the holding material 13, by forming the protrusions 51 and the flanges 52 (not shown) only on the both side portions 50A1 of the intersection C2, the protective film 50A is easily stretched and curved. FIG. 9 shows a state in which such a holding material 13 is developed on a plane.

  FIG. 10 shows a state in which the holding material 13 is wound around the catalyst carrier 12 having a cross-sectional track shape. The holding member 13 is engaged with the convex portion 42 and the concave portion 43 directly above the center portion of one flat surface portion 12A of the catalyst carrier 12, and is greatly curved so as to cover the curved portion 12B of the catalyst carrier 12, and the stretch amount Is also getting bigger. Therefore, in the protective film 50A of the holding material 13, the protrusions 51 and the flanges 52 (not shown) are formed only on the portion 50A2 that covers the curved portion 12B.

  FIG. 11 shows a state in which the holding material 13 is wound around the catalyst carrier 12 having a cross-sectional shape in which both ends of the major axis X of the ellipse are cut so as to be orthogonal to the major axis X. The convex portion 42 and the concave portion 43 of the holding material 13 are engaged immediately above one intersection C <b> 1 with the minor axis Y of the surface of the catalyst carrier 12. Further, in the catalyst carrier 12, the intersection C3 between the line that cuts the major axis X and the original ellipse is bent, and the holding member 13 is also bent at a portion covering the intersection C3. Therefore, in the protective film 50A of the holding material 13, the protrusions 51 and the flanges 52 (not shown) are formed only in the portion 50A3 that covers the intersection C3.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not limited at all by this.

(Holding material production)
Using a polyethylene nonwoven fabric with a basis weight of 5 g / m ² and a width of 70 mm, a protective film was prepared by performing crease processing and adjusting the increment of basis weight as shown in Table 1. In addition, 0% of grammage indicates that the nonwoven fabric before wrinkle processing was used as it was.

Each protective film was bonded to one side of an alumina fiber substrate having a longitudinal length of 530 mm and a width length of 144 mm and a basis weight of 1200 g / m ² by a hot breath to obtain a holding material. The protective film having a basis weight increase of 200% was difficult to join by hot pressing, and was joined using an adhesive.

(Evaluation of winding properties)
Steel pipes with different diameters were prepared, and the holding material was wound in order from the steel pipe with the largest diameter, and the smallest diameter that could be wound was obtained. The results are also shown in Table 1, but the holding material joined with the protective film that has been subjected to glazing so that the increase in basis weight is 100% or less is the holding material joined with the protective film that has not been glazed. It is clear that it can be wound around a steel pipe having a smaller diameter, and the winding property on the catalyst carrier is improved.

11 Metal casing 12 Catalyst carrier 13 Holding material 45 Base material 50, 50A Protective film 51 Protrusion 52 皺 60 Opening

Claims (8)

A holding material used in a catalytic converter comprising a catalyst carrier, a metal casing that houses the catalyst carrier, and a holding material that is wound around the catalyst carrier and interposed in a gap between the catalyst carrier and the metal casing. And
A holding material for a catalytic converter, wherein a protective film having protrusions or wrinkles is joined to a surface of an inorganic fiber substrate on a metal casing side.   2. The holding material for a catalytic converter according to claim 1, wherein the basis weight of the protective film is 1.05 to 2 times the basis weight before the protrusions or wrinkles are formed.   The holding material for a catalytic converter according to claim 1 or 2, wherein the protective film has an opening.   4. The holding material for a catalytic converter according to claim 3, wherein the opening ratio in the protective film is 10 to 45%.   5. The protective film according to claim 1, wherein the protective film is formed only on a portion that covers a portion having a maximum curvature of the cross-sectional shape of the catalyst carrier and is used for a catalyst carrier having a flat cross-sectional shape. The holding material for a catalytic converter according to item 1. Catalytic converter holding material according to any one of claims 1 to 5, the basis weight of the protective film is characterized by a 1 to 30 g / m ^2.   The protective film according to any one of claims 1 to 6, wherein the protective film comprises at least one of polyethylene terephthalate, polyethylene, polypropylene, or cellulose.   The organic component of the whole holding material is 5 mass% or less of the total amount of the holding material, The holding material for catalytic converters according to any one of claims 1 to 7.

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