JP2014202187A - Holding seal material, method of manufacturing the same, and exhaust emission control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a holding seal material which includes inorganic fibers hardly breaking when the holding seal material is inserted into a metal casing after being wound around an exhaust gas treatment body, which is easily installed, and which enables the exhaust gas treatment body to be hardly deviated.SOLUTION: A holding seal material is used for an exhaust emission control device which includes an exhaust gas treatment body, a metal casing storing the exhaust gas treatment body, and the holding seal material arranged between the exhaust gas treatment body and the metal casing, and formed of the inorganic fibers. The holding seal material has a first main surface for contacting the metal casing, and a second main surface for contacting the exhaust gas treatment body. The first main surface and the second main surface are each impregnated with organic binders, respectively. A glass-transition temperature of the organic binder A with which the first main surface is impregnated is higher than a glass-transition temperature of an organic binder B with which the second main surface is impregnated.

Description

The present invention relates to a holding sealing material, a method for manufacturing the holding sealing material, and an exhaust gas purification apparatus.

Particulate matter (hereinafter also referred to as PM) is contained in exhaust gas discharged from an internal combustion engine such as a diesel engine. In recent years, it has been a problem that this PM is harmful to the environment and the human body. . Further, since the exhaust gas contains harmful gas components such as CO, HC and NOx, there is a concern about the influence of the harmful gas components on the environment and the human body.

Therefore, as an exhaust gas purification device that collects PM in exhaust gas and purifies harmful gas components, an exhaust gas treatment body made of porous ceramics such as silicon carbide and cordierite, and a metal that houses the exhaust gas treatment body Various exhaust gas purifying apparatuses composed of a casing and a holding sealing material made of an inorganic fiber aggregate disposed between an exhaust gas treating body and a metal casing have been proposed. This holding sealing material prevents the exhaust gas treating body from being damaged by contact with the metal casing covering the outer periphery due to vibrations or impacts caused by traveling of an automobile or the like, or from between the exhaust gas treating body and the metal casing. The main purpose is to prevent the exhaust gas from leaking. Therefore, the holding sealing material is required to have a function of increasing the surface pressure generated by the repulsive force caused by being compressed and holding the exhaust gas treating body reliably. In addition, such a holding sealing material is wound around the exhaust gas treatment body and accommodated in a metal casing. At this time, the end of the inorganic fiber constituting the holding sealing material is in direct contact with the operator and feels uncomfortable. There was a problem of reducing work efficiency.

Conventionally, in order to solve such a problem, a method for preventing protrusion of inorganic fibers by coating the surface of the holding sealing material with a solution containing an organic compound or an inorganic compound is known. (For example, refer to Patent Document 1).

JP 2002-13415 A

However, when manufacturing the exhaust gas purification device using the holding sealing material created by the method disclosed in Patent Document 1, the operator's discomfort can be improved, but the holding sealing material is wound. There has been no study on the ease of housing the exhaust gas treating body in the metal casing. Therefore, depending on the organic binder to be impregnated, it is necessary to apply a large force at the time of accommodation, the inorganic fibers constituting the holding sealing material are damaged, the exhaust gas purifier is displaced, and it takes time for accommodation, and productivity is reduced. There was a problem to do.

The present invention has been made to solve the above-described problem, and when the holding sealing material is wrapped around the exhaust gas treating body and inserted into the metal casing, the housing can be easily accommodated, and the inorganic fiber is It is an object of the present invention to provide a holding seal material that is less likely to break and the displacement of the holding seal material and the exhaust gas treating body, a method for manufacturing the holding seal material, and an exhaust gas purification device.

In order to achieve the above object, the holding sealing material of the present invention includes an exhaust gas treating body, a metal casing that houses the exhaust gas treating body, and an inorganic fiber disposed between the exhaust gas treating body and the metal casing. A holding seal material used for an exhaust gas purification apparatus comprising the holding seal material, wherein the holding seal material is a first main surface in contact with the metal casing and a second main surface in contact with the exhaust gas treatment body. And the first main surface and the second main surface are impregnated with an organic binder, and the glass transition temperature of the organic binder A impregnated into the first main surface is the second main surface. It is characterized by being higher than the glass transition temperature of the organic binder B impregnated in the main surface.

In the holding sealing material of the present invention, the glass transition temperature of the organic binder A is higher than the glass transition temperature of the organic binder B. In general, the glass transition temperature of the resin correlates with the hardness and slipperiness of the resin. That is, the organic binder A impregnated in a predetermined region including the first main surface has a glass transition temperature higher than the organic binder B impregnated in the predetermined region including the second main surface. The resin constituting A is harder than the resin constituting organic binder B. Therefore, the first main surface of the holding sealing material impregnated with the organic binder A is relatively harder than the second main surface impregnated with the organic binder B, and is in contact with the first main surface. The coefficient of static friction against the metal casing is low and slippery. On the other hand, the second main surface that is in contact with the exhaust gas treating body is relatively soft compared to the first main surface, and therefore has a high coefficient of static friction with respect to the exhaust gas treating body and is difficult to slip.
As described above, when the holding sealing material wound with the holding sealing material is accommodated in the metal casing, the first main surface of the holding sealing material impregnated with the organic binder A is slipped with respect to the metal casing. It becomes easy and can be easily accommodated in a metal casing, and productivity improves. In addition, since an excessive force is not applied to the holding sealing material at the time of accommodation, it is possible to prevent the inorganic fibers and the mat from being damaged. On the other hand, the second main surface of the holding sealing material impregnated with the organic binder B becomes less slippery with respect to the exhaust gas treating body, and when the holding sealing material wrapped with the holding sealing material is accommodated in the metal casing. The exhaust gas treating body and the holding sealing material are difficult to shift.

In the holding sealing material of the present invention, the glass transition temperature of the organic binder A is preferably 5 ° C. or higher and 50 ° C. or lower, and the glass transition temperature of the organic binder B is desirably −50 ° C. or higher and lower than 5 ° C.
Since the glass transition temperature of the organic binder A is close to room temperature or higher than room temperature, the first main surface is likely to be relatively hard and slippery with respect to the metal casing. On the other hand, since the glass transition temperature of the organic binder B is lower than room temperature, it is relatively soft and is difficult to slip with respect to the exhaust gas treating body. Since the holding sealing material of the present invention is configured as described above, when the holding sealing material wrapped with the holding sealing material is accommodated in the metal casing by press fitting or the like, the first main surface of the holding sealing material is The metal casing becomes slippery and can be easily accommodated in the metal casing. Further, the second main surface of the holding sealing material is less slippery with respect to the exhaust gas treating body, and when the holding sealing material wrapped with the holding sealing material is accommodated in the metal casing, the exhaust gas treating body, the holding sealing material, Is less likely to slip.

When the organic binder A has a glass transition temperature of less than 5 ° C., when the exhaust gas treating body and the holding sealing material are accommodated in the metal casing, the accommodating operation may not proceed smoothly. Even if the glass transition temperature of the organic binder A exceeds 50 ° C., the slipperiness of the holding sealing material with respect to the metal casing is almost the same as that of the glass transition temperature of 50 ° C.

When the glass transition temperature of the organic binder B is less than −50 ° C., the softness is the same as that of the glass transition temperature of −50 ° C. On the other hand, when the glass transition temperature of the organic binder B is 5 ° C. or higher, the glass transition temperature is close to room temperature and becomes hard, so that the holding sealing material is easily slipped with respect to the exhaust gas treating body.

In the holding sealing material of the present invention, the organic binder A is impregnated in a predetermined region including the first main surface, and the organic binder B is impregnated in a predetermined region including the second main surface. The amount of impregnation of the organic binder A impregnated in a predetermined region including the first main surface is 0.2 to 12.0 parts by weight with respect to 100 parts by weight of the inorganic fiber, and the second The impregnation amount of the organic binder B impregnated in a predetermined region including the main surface is desirably 0.2 to 12.0 parts by weight with respect to 100 parts by weight of the inorganic fiber. When the impregnation amount of the organic binder A is less than 0.2 parts by weight with respect to 100 parts by weight of the inorganic fibers, the first main surface of the holding sealing material does not become so hard, and the housing operation may not be smooth. On the other hand, when the impregnation amount of the organic binder A exceeds 12.0 parts by weight, the effect of easy accommodation is not changed, but there is a problem that a large amount of decomposition gas is generated by the exhaust gas. . When the impregnation amount of the organic binder B is less than 0.2 parts by weight with respect to 100 parts by weight of the inorganic fiber, the holding sealing material is not easily slipped. Therefore, the exhaust gas treating body and the holding sealing material are combined. When accommodated in the metal casing, the exhaust gas treatment body may shift, while if the impregnation amount of the organic binder B exceeds 12.0 parts by weight, the effect of easy accommodation is not changed, There may be a problem that a large amount of decomposition gas is generated by the exhaust gas.

In the holding sealing material of the present invention, the total impregnation amount of the organic binder A and the organic binder B is 0.5 to 3.0 parts by weight with respect to 100 parts by weight of the inorganic fibers constituting the holding sealing material. It is desirable. When the total impregnation amounts of the organic binder A and the organic binder B are 0.5 parts by weight or more, it becomes easy to suitably adjust the static friction coefficient between the first main surface and the second main surface. When the total impregnation amount of the organic binder A and the organic binder B is 3.0 parts by weight or less, it becomes easy to sufficiently suppress the generation of a large amount of decomposition gas by the exhaust gas.

In the holding sealing material of the present invention, it is desirable that the organic binder A and the organic binder B contain at least an acrylic resin.
Since the acrylic resin can easily adjust the glass transition temperature, it becomes easy to adjust the glass transition temperature of the organic binder A and the organic binder B impregnated in the first main surface and the second main surface, It becomes easy to adjust the slipperiness and the difficulty of slipping.

The inorganic fiber constituting the holding sealing material of the present invention is preferably composed of at least one selected from the group consisting of alumina fiber, silica fiber, alumina silica fiber, mullite fiber, biosoluble fiber and glass fiber. .

In the above holding sealing material, when the inorganic fiber is at least one of alumina fiber, alumina-silica fiber, and silica fiber, it is excellent in heat resistance, so that the exhaust gas becomes high temperature. However, the function as the holding sealing material can be sufficiently maintained without affecting the inorganic fibers. In addition, when the inorganic fiber is a biosoluble fiber, when producing an exhaust gas purification device using a holding sealing material, even if the scattered inorganic fiber is inhaled, it is dissolved in the living body. Will not harm your health.
Moreover, the slipperiness with respect to a metal casing etc. can be adjusted comparatively easily by impregnating an organic binder using the said inorganic fiber.

The manufacturing method of the holding sealing material of the present invention includes a mat preparing step of preparing a mat for holding sealing material made of inorganic fibers subjected to needle punching treatment, and droplets of an organic binder-containing liquid containing an organic binder A. It includes an impregnation step of spraying on the first main surface of the mat and a drying step of drying the mat containing the organic binder-containing liquid.

The method for producing the holding sealing material of the present invention can produce the above-described holding sealing material of the present invention relatively easily. In addition, the holding sealing material manufactured by the method for manufacturing the holding sealing material of the present invention is impregnated with the organic binder A on the first main surface, so the first main surface is slippery with respect to the metal casing, The work at the time of accommodating the exhaust gas treating body and the holding sealing material in the metal casing becomes easy.

In the manufacturing method of the holding sealing material of the present invention, the impregnation step may further include a step of spraying droplets of the organic binder-containing liquid containing the organic binder B against the second main surface of the mat. desirable. Since the second main surface is impregnated with the organic binder B, the second main surface of the holding sealing material becomes less slippery with respect to the exhaust gas treating body, and the exhaust gas treating body and the holding sealing material are connected to the metal. Deviation between the exhaust gas treating body and the holding sealing material when accommodated in the casing can be prevented, and the main work is facilitated.

The exhaust gas purifying apparatus of the present invention includes a metal casing, an exhaust gas treatment body accommodated in the metal casing, and a holding member that is wound around the exhaust gas treatment body and disposed between the exhaust gas treatment body and the metal casing. An exhaust gas purifying apparatus including a sealing material, wherein the above-described holding sealing material is used as the holding sealing material.

The holding sealing material of the present invention includes a first main surface and a second main surface, the first main surface is in contact with the metal casing, and the second main surface is the exhaust gas treating body. The first main surface and the second main surface are impregnated with two kinds of organic binders, and the glass transition temperature of the organic binder A impregnated into the first main surface is It is higher than the glass transition temperature of the organic binder B impregnated in the second main surface.

In the exhaust gas purifying apparatus of the present invention, since the organic binder A is impregnated on the first main surface, the holding sealing material becomes slippery with respect to the metal casing. Therefore, when the holding sealing material and the exhaust gas treating body are accommodated in the exhaust gas purification device, the inorganic fibers are hardly damaged and can be easily accommodated. Accordingly, since the second main surface is impregnated with the organic binder B, the holding seal material is less likely to slip with respect to the exhaust gas treatment body, and the holding seal material is less likely to be displaced with respect to the exhaust gas treatment body. The exhaust gas purifying apparatus in which the material and the exhaust gas treating body are appropriately arranged is obtained.
In the exhaust gas purifying apparatus, when the exhaust gas is introduced, the organic binder is decomposed and disappeared, and the action to expand the holding seal material works. Therefore, the holding seal material is held with an appropriate holding force, and the pressure of the exhaust gas is increased. For example, the exhaust gas treating body does not come out of the metal casing.

Fig.1 (a) is a perspective view which shows typically an example of the holding sealing material of this invention, FIG.1 (b) is AA sectional view taken on the line of the holding sealing material shown to Fig.1 (a). is there. FIG. 2 is a cross-sectional view schematically showing an example of the exhaust gas purifying apparatus of the present invention. FIG. 3 is a perspective view schematically showing an example of the exhaust gas treating body constituting the exhaust gas purifying apparatus of the present invention. FIG. 4 is a perspective view schematically showing an example of the method for manufacturing the exhaust gas purifying apparatus of the present invention. FIGS. 5A and 5B are schematic diagrams showing an example of a method for measuring the coefficient of static friction.

(Detailed description of the invention)
Hereinafter, the present invention will be specifically described. However, the present invention is not limited to the following configurations, and can be applied with appropriate modifications without departing from the scope of the present invention.

Hereinafter, the holding sealing material of the present invention will be described.

Fig.1 (a) is a perspective view which shows typically an example of the holding sealing material of this invention, FIG.1 (b) is AA sectional view taken on the line of the holding sealing material shown to Fig.1 (a). is there.

As shown in FIG. 1A, the holding sealing material 120 of the present invention has a predetermined length in the longitudinal direction (hereinafter, indicated by an arrow L in FIG. 1) and a width (indicated by an arrow W in FIG. 1). And a mat having a flat plate shape that is substantially rectangular in a plan view and has a thickness (indicated by an arrow T in FIG. 1). Further, as shown in FIG. 1B, the holding sealing material 120 of the present invention includes a first main surface 121 and a second main surface 122 that is a main surface opposite to the first main surface 121. It has.

In the holding sealing material 120 shown in FIG. 1, a convex portion is formed on the first end 123 which is one of the end portions on the length direction side of the holding sealing material 120, and the other end. A recess is formed in the second end portion 124 that is a portion. The convex portion and the concave portion of the holding sealing material 120 are shaped so as to be fitted to each other when the holding sealing material 120 is wound around the exhaust gas treatment body in order to assemble an exhaust gas purifying device described later.

The holding sealing material 120 contains an inorganic fiber as a main component, and the inorganic fiber is impregnated with an organic binder. That is, the first main surface of the holding sealing material 120 is impregnated with the organic binder A, and the second main surface is impregnated with the organic binder B.

Although the said inorganic fiber is not specifically limited, It is desirable to be comprised from at least 1 type selected from the group which consists of an alumina fiber, a silica fiber, an alumina silica fiber, a mullite fiber, a biosoluble fiber, and a glass fiber.

In addition to alumina, the alumina fiber may contain additives such as calcia, magnesia, zirconia, and the like.
The composition ratio of the alumina silica fiber is preferably Al ₂ O ₃ : SiO ₂ = 60: 40 to 80:20 by weight, and Al ₂ O ₃ : SiO ₂ = 70: 30 to 74:26. More desirable.
The biosoluble fiber is, for example, an inorganic fiber containing at least one compound selected from the group consisting of an alkali metal compound, an alkaline earth metal compound, and a boron compound in addition to silica and the like.

Since the biosoluble fiber made of these compounds is easily dissolved even when taken into the human body, the mat containing these inorganic fibers is excellent in safety to the human body.

The specific composition of the biosoluble fiber includes 60 to 85% by weight of silica and 15 to 40% by weight of at least one compound selected from the group consisting of alkali metal compounds, alkaline earth metal compounds and boron compounds. Composition. The silica refers to SiO or SiO ₂ .

Examples of the alkali metal compound include sodium and potassium oxides, and examples of the alkaline earth metal compound include magnesium, calcium, and barium oxides. Examples of the boron compound include boron oxide.

In the composition of the biosoluble fiber, when the silica content is less than 60% by weight, it is difficult to produce by a glass melting method, and it is difficult to fiberize.
In addition, when the silica content is less than 60% by weight, the alkali metal compound, the alkaline earth metal compound, and boron are structurally fragile because the content of the flexible silica is small, and are easily soluble in physiological saline. Since the ratio of at least one compound selected from the group consisting of compounds is relatively high, the biosoluble fiber tends to be too soluble in physiological saline.

On the other hand, if the content of silica exceeds 85% by weight, the proportion of at least one compound selected from the group consisting of alkali metal compounds, alkaline earth metal compounds and boron compounds is relatively low, so that the biosoluble fiber is It tends to be too difficult to dissolve in physiological saline.
The silica content is calculated by converting the amounts of SiO and SiO ₂ into SiO ₂ .

In the composition of the biosoluble fiber, the content of at least one compound selected from the group consisting of an alkali metal compound, an alkaline earth metal compound, and a boron compound is preferably 15 to 40% by weight. When the content of at least one compound selected from the group consisting of an alkali metal compound, an alkaline earth metal compound, and a boron compound is less than 15% by weight, the biosoluble fiber is hardly dissolved in physiological saline.

On the other hand, when the content of at least one compound selected from the group consisting of an alkali metal compound, an alkaline earth metal compound and a boron compound exceeds 40% by weight, it is difficult to produce and fiberize by the glass melting method. Further, when the content of at least one compound selected from the group consisting of an alkali metal compound, an alkaline earth metal compound and a boron compound exceeds 40% by weight, it is structurally fragile and the biosoluble fiber is easily soluble in physiological saline. Too much.

The solubility of the biosoluble fiber in physiological saline is desirably 30 ppm or more. If the solubility of the biosoluble fiber is less than 30 ppm, when the inorganic fiber is taken into the body, it is difficult to be discharged out of the body, which is undesirable for health.

The glass fiber is a glassy fiber containing silica and alumina as main components and containing calcia, titania, zinc oxide and the like in addition to the alkali metal.

The average fiber length of the inorganic fibers constituting the holding sealing material 120 is desirably 5 to 150 mm, and more desirably 10 to 80 mm.
If the average fiber length of the inorganic fibers is less than 5 mm, the fiber length of the inorganic fibers is too short, so that the entanglement between the inorganic fibers becomes insufficient, and the shear strength of the holding sealing material decreases. Moreover, since the fiber length of an inorganic fiber will be too long when the average fiber length of an inorganic fiber exceeds 150 mm, the handleability of the inorganic fiber at the time of manufacture of a holding sealing material will fall. As a result, the windability around the exhaust gas treating body is lowered, and the holding sealing material is easily broken.

The average fiber diameter of the inorganic fibers constituting the holding sealing material 120 of the present invention is preferably 1 to 20 μm, and more preferably 3 to 10 μm.
When the average fiber diameter of the inorganic fibers is 1 to 20 μm, the strength and flexibility of the inorganic fibers are sufficiently high, and the shear strength of the holding sealing material can be improved.
If the average fiber diameter of the inorganic fibers is less than 1 μm, the inorganic fibers are easily cut into thin pieces, so that the tensile strength of the inorganic fibers becomes insufficient. On the other hand, when the average fiber diameter of the inorganic fibers exceeds 20 μm, the flexibility of the inorganic fibers is insufficient because the inorganic fibers are not easily bent.

Weight per unit area of the holding sealing material of the present invention (weight per unit area) is not particularly limited, is preferably a 200~4000g / ^{m 2,} and more desirably 1000 to 3000 g / ^{m 2.} When the weight per unit area of the holding sealing material is less than 200 g / m ² , the holding power is not sufficient, and the exhaust gas treating body may easily fall off the holding sealing material when an exhaust gas purification device is manufactured. On the other hand, when the weight per unit area of the holding seal material exceeds 4000 g / m ² , the volume of the holding seal material is difficult to decrease, and it may be difficult to wind the holding seal material around the exhaust gas treatment body.

Further, the bulk density of the holding sealing material of the present invention (the bulk density of the holding sealing material before winding) is not particularly limited, but is desirably 0.10 to 0.30 g / cm ³ . When the bulk density of the holding sealing material is less than 0.10 g / cm ³ , the entanglement of the inorganic fibers is weak and the inorganic fibers are easily peeled off, so that it is difficult to keep the shape of the holding sealing material in a predetermined shape.
On the other hand, if the bulk density of the holding sealing material exceeds 0.30 g / cm ³ , the holding sealing material becomes hard, the wrapping property around the exhaust gas treating body is lowered, and the holding sealing material is easily broken.

The “substantially rectangular shape in plan view” described in the present invention is a concept including a convex portion and a concave portion. The “substantially rectangular shape in plan view” also includes a shape having a corner other than 90 °. For example, the corner of the mat may have a sharp or obtuse angle or may have a curvature.

The holding sealing material of the present invention may further contain an expansion material. It is desirable that the expansion material has a characteristic of expanding in the range of 400 to 800 ° C.
If the mat contains an expanding material, the mat will expand in the range of 400-800 ° C, so it can be used as a holding sealing material even in a high temperature range exceeding 700 ° C where the strength of the glass fiber decreases. It is possible to improve the holding power when performing.

Examples of the expanding material include vermiculite, bentonite, phlogopite, pearlite, expandable graphite, and expandable fluoride mica. These expanding materials may be used alone or in combination of two or more.
The addition amount of the expansion material is not particularly limited, but is preferably 10 to 50% by weight and more preferably 20 to 30% by weight with respect to the total weight of the mat.

When the holding sealing material of the present invention is used as a holding sealing material for an exhaust gas purification device, the number of holding sealing materials constituting the exhaust gas purification device is not particularly limited, and may be one holding sealing material or coupled to each other. A plurality of holding sealing materials may be used, but one holding sealing material is particularly desirable. When one holding sealing material is used as the holding sealing material of the exhaust gas purifying apparatus, there is no contact portion between the holding sealing materials, so that the inorganic fibers can be prevented from being damaged due to friction between the holding sealing materials. It is possible to prevent the holding sealing materials from being displaced during storage.
The method of joining a plurality of holding sealing materials is not particularly limited, and examples thereof include a method of sewing the holding sealing materials by sewing, a method of bonding the holding sealing materials with an adhesive tape or an adhesive, and the like. It is done.

The thickness of the holding sealing material 120 is not particularly limited, but is desirably 2.0 to 20 mm.
When the thickness of the holding sealing material 120 exceeds 20 mm, the flexibility of the holding sealing material 120 is lost, so that it becomes difficult to handle the holding sealing material 120 when it is wound around the exhaust gas treatment body 130. Further, winding wrinkles and cracks are likely to occur in the holding sealing material 120.
When the thickness of the holding sealing material 120 is less than 2.0 mm, the surface pressure of the holding sealing material 120 is not sufficient to hold the exhaust gas treating body. Therefore, the exhaust gas treating body 130 is likely to fall off. Further, when a volume change occurs in the exhaust gas treatment body 130, the holding sealing material 120 becomes difficult to absorb the volume change of the exhaust gas treatment body 130. Therefore, cracks and the like are easily generated in the exhaust gas treating body 130.

The first main surface 121 of the holding sealing material 120 shown in FIG. 1 is impregnated with an organic binder A having a glass transition temperature higher than that of the organic binder B impregnated on the second main surface.
When the first main surface is impregnated with the organic binder A, the first main surface becomes relatively hard, and the holding seal material 120 has a smaller coefficient of static friction with respect to the metal casing 110 and becomes slippery. Therefore, when the holding sealing material 120 and the exhaust gas treating body 130 are accommodated in the metal casing 110, the holding sealing material 120 and the exhaust gas treating body 130 can be smoothly accommodated in the metal casing, and further retained by the accommodating operation. It can prevent that the inorganic fiber which comprises the sealing material 120 is damaged or scattered.

In addition, in the holding sealing material 120, the second main surface 122 is impregnated with an organic binder B having a glass transition temperature lower than that of the organic binder A impregnated in the first main surface.
By impregnating the second main surface with the organic binder B, the second main surface becomes soft, and the second main surface of the holding sealing material 120 has a higher coefficient of static friction than the exhaust gas treating body 130. Become slippery. Therefore, when the holding sealing material 120 and the exhaust gas treatment body 130 are accommodated in the metal casing 110, the holding seal material 120 is unlikely to be displaced with respect to the exhaust gas treatment body 130, and the exhaust gas treatment body around which the holding sealing material is wound is attached to the metal casing. It becomes easy to accommodate efficiently.

The organic binder A only needs to be impregnated in the region of 20% of the thickness of the holding sealing material from the first main surface. If it is difficult to reduce the impregnation region, the thickness of the holding sealing material is sufficient. May be impregnated in a half of the region. If the organic binder A is impregnated in the region of 20% of the thickness of the holding sealing material from the first main surface, the softness (hardness) of the first main surface can be suitably adjusted.

The organic binder B only needs to be impregnated in the region of 20% of the thickness of the holding sealing material from the second main surface. However, if it is difficult to reduce the impregnation region, the thickness of the holding sealing material May be impregnated in a half of the region. When the organic binder B is included in the region of 20% of the thickness of the holding sealing material from the second main surface, the softness (hardness) of the second main surface can be suitably adjusted.

The weight of the organic binder A impregnated in a predetermined region including the first main surface of the holding sealing material of the present invention is not particularly limited, but is 0.2 in terms of solid content with respect to 100 parts by weight of the inorganic fibers. It is preferably ˜12.0 parts by weight, more preferably 0.5 to 6.0 parts by weight, and even more preferably 0.5 to 3.0 parts by weight.

When the weight of the organic binder A is less than 0.2 parts by weight with respect to 100 parts by weight of the inorganic fibers, the impregnation amount of the organic binder is too small, and the first main surface of the holding sealing material does not become hard, and the holding sealing material It becomes difficult to easily accommodate the exhaust gas treating body wrapped with the metal casing in the metal casing. On the other hand, when the weight of the organic binder A exceeds 12.0 parts by weight with respect to 100 parts by weight of the inorganic fibers, the effect that the holding sealing material and the exhaust gas treating body can be easily accommodated in the metal casing is almost the same. However, since the amount of the organic binder impregnated is too large, the amount of the organic component decomposed by the heat of the exhaust gas increases, which adversely affects the surrounding environment.

The organic binder A and the organic binder B are not particularly limited as long as the softness (hardness) of the first main surface and the second main surface can be adjusted. For example, acrylic resin, polyethylene type Examples thereof include resins, polypropylene resins, polyvinyl chloride resins, polystyrene resins, rubber resins, and the like, and two or more resins may be included. In these, it is desirable that it is acrylic resin, and it is more desirable that it is acrylic rubber.

The organic binder A impregnated on the first main surface of the holding sealing material of the present invention is desirably impregnated in an area of 50% or more of the first main surface, and impregnated in an area of 80% or more. It is more desirable.

The weight of the organic binder B impregnated in the second main surface of the holding sealing material of the present invention is not particularly limited, but is 0.2 to 12.0 weight in terms of solid content with respect to 100 parts by weight of inorganic fibers. Parts, more preferably 0.5 to 6.0 parts by weight, and even more preferably 0.5 to 3.0 parts by weight.

When the impregnation amount of the organic binder B is less than 0.2 parts by weight with respect to 100 parts by weight of the inorganic fiber, the second main surface is not soft because the impregnation amount of the organic binder is too small, and the exhaust gas treatment body The holding sealing material is easily displaced. On the other hand, when the impregnation amount of the organic binder B exceeds 12.0 parts by weight with respect to 100 parts by weight of the inorganic fiber, the effect that the holding sealing material and the exhaust gas treating body can be easily accommodated in the metal casing is almost the same. Since the amount of the organic binder impregnated is too large, the amount of organic components decomposed by the heat of the exhaust gas is increased, which adversely affects the surrounding environment.

In the holding sealing material of the present invention, the total of the organic binder A impregnated on the first main surface and the organic binder B impregnated on the second main surface is based on 100 parts by weight of the inorganic fibers constituting the holding sealing material. And, it is desirable that it is 0.5 to 3.0 parts by weight in terms of solid content. When the total weight of the organic binder A impregnated in the first main surface and the organic binder B impregnated in the second main surface is 0.5 parts by weight or more, the first main surface and the metal casing It becomes easy to suitably adjust the static friction coefficient and the static friction coefficient between the second main surface and the exhaust gas treating body. When the total weight of the organic binder A impregnated on the first main surface and the organic binder B impregnated on the second main surface is 3.0 parts by weight or less, a large amount of decomposition gas is generated by the exhaust gas. Can be sufficiently suppressed.

The organic binder B impregnated in the second main surface of the holding sealing material of the present invention is desirably impregnated in an area of 50% or more of the second main surface, and is impregnated in an area of 80% or more. It is more desirable.

The glass transition temperature (Tg) of the organic binder A is desirably 5 ° C. or higher and 50 ° C. or lower. On the other hand, the glass transition temperature (Tg) of the organic binder B is desirably −50 ° C. or higher and lower than 5 ° C.

The holding sealing material 120 of the present invention may further contain an inorganic binder. The inorganic binder is not particularly limited as long as it can fix the inorganic fibers by adhering to the adjacent inorganic fibers, but is preferably alumina sol, silica sol or the like.

Next, a method for manufacturing the holding sealing material will be described.
The manufacturing method of the holding sealing material of the present invention can be suitably applied to the above-described method of manufacturing the holding sealing material of the present invention.

The manufacturing method of the holding sealing material includes a mat preparing step of preparing a mat for holding sealing material made of inorganic fibers subjected to needle punching treatment, and droplets of an organic binder-containing liquid containing an organic binder A. It includes an impregnation step of spraying the first main surface and a drying step of drying the mat containing the organic binder-containing liquid.

(A) Mat Preparation Step In the manufacturing method of the holding sealing material, first, a mat preparing step of preparing a mat for holding sealing material made of inorganic fibers subjected to needle punching is performed.
The mat constituting the holding sealing material 120 can be obtained by various methods. For example, the mat can be manufactured by the following method. That is, first, for example, an inorganic fiber precursor having an average fiber diameter of 3 to 10 μm is prepared by spinning a spinning mixture using a basic aluminum chloride aqueous solution and silica sol as raw materials by a blowing method. Subsequently, the inorganic fiber precursor is compressed to create a continuous sheet-like material having a predetermined size, which is subjected to needle punching treatment, and then fired to prepare a mat for holding sealing material. Is completed.

(B) Impregnation step Next, an impregnation step of impregnating the first main surface of the mat with the organic binder A is performed. A method for impregnating the first main surface of the mat with the organic binder A is not particularly limited, but a spray coating method in which an organic binder-containing liquid containing the organic binder A is sprayed and sprayed can be used. The impregnation amount of the organic binder A is 0.2 to 12.0 parts by weight in terms of solid content with respect to 100 parts by weight of the inorganic fibers constituting the holding sealing material after finishing the drying step (c) described later. It is desirable to adjust so that.

In the impregnation step, after the impregnation of the organic binder A is completed, an impregnation step of impregnating the second main surface of the mat with the organic binder B may be performed. A method for impregnating the first main surface of the mat with the organic binder B is not particularly limited, and a spray coating method in which an organic binder-containing liquid containing the organic binder B is sprayed and sprayed can be used. The impregnation amount of the organic binder B is 0.2 to 12.0 parts by weight in terms of solid content with respect to 100 parts by weight of the inorganic fibers constituting the holding sealing material after finishing the drying step (c) described later. It is desirable to adjust so that.

(C) Drying step A drying step of drying the mat to which the organic binder is attached at a temperature of about 110 to 140 ° C. is performed to evaporate the moisture to obtain a mat to which the organic binder is attached. As a drying method, hot air drying can be used. Drying may be performed after impregnating the organic binder A, and then drying may be performed again by impregnating the organic binder B. After impregnating the organic binder A and the organic binder B, moisture is removed by one drying. May be.

(A) The mat preparation step may include a step of impregnating an inorganic fiber with an inorganic binder. The method and procedure for impregnating the inorganic fiber with the inorganic binder is not particularly limited. For example, the mat may be impregnated with the inorganic binder by impregnating the mat with a solution containing the inorganic binder after the mat preparation step. The mat may be impregnated with the inorganic binder by dropping the inorganic binder onto the mat by a method such as curtain coating. Thereafter, the amount of the inorganic binder attached can be adjusted by sucking and dehydrating the mat to which the inorganic binder is attached.
When the inorganic fiber is impregnated with the inorganic binder, it is desirable to impregnate the inorganic binder before impregnating the organic binder. This is because the slipperiness can be controlled by bringing the impregnated organic binder into contact with the metal casing or the exhaust gas treating body.

(Exhaust gas purification device)
The holding sealing material of the present invention can be used as a holding sealing material for an exhaust gas purification device.

Hereinafter, the exhaust gas purifying apparatus of the present invention will be described.
FIG. 2 is a cross-sectional view schematically showing an example of the exhaust gas purifying apparatus of the present invention. As shown in FIG. 2, the exhaust gas purification apparatus 100 of the present invention includes a metal casing 110, an exhaust gas treatment body 130 accommodated in the metal casing 110, and a holding disposed between the exhaust gas treatment body 130 and the metal casing 110. And a sealing material 120.
The exhaust gas treatment body 130 has a columnar shape in which a large number of cells 155 are arranged in parallel in the longitudinal direction with a cell wall 156 interposed therebetween. Note that an end of the metal casing 110 is connected to an introduction pipe for introducing the exhaust gas discharged from the internal combustion engine and an exhaust pipe for discharging the exhaust gas that has passed through the exhaust gas purification device to the outside, if necessary. become.

In the exhaust gas purifying apparatus 100 shown in FIG. 2, an exhaust gas filter (honeycomb filter) in which one of the cells is sealed with a sealing material 158 is used as the exhaust gas treatment body 130. Alternatively, a catalyst carrier that is not sealed with a sealing material may be used.

The case where the exhaust gas passes through the exhaust gas purification apparatus 100 having the above-described configuration will be described below with reference to FIG.
As shown in FIG. 2, the exhaust gas discharged from the internal combustion engine and flowing into the exhaust gas treatment device 100 (in FIG. 2, the exhaust gas is indicated by G and the flow of the exhaust gas is indicated by arrows) is an exhaust gas treatment body (honeycomb filter) 130. Flows into one cell 155 opened to the exhaust gas inflow side end face 130 a and passes through the cell wall 156 separating the cell 155. At this time, PM in the exhaust gas is collected by the cell wall 156, and the exhaust gas is purified. The purified exhaust gas flows out from the other cell 155 opened in the exhaust gas outflow side end face 130b and is discharged outside.

Next, the exhaust gas treatment body (honeycomb filter) and the metal casing constituting the exhaust gas purification apparatus of the present invention will be described.
In addition, about the structure of the holding sealing material which comprises an exhaust gas purification apparatus, since it has already demonstrated as the holding sealing material of this invention, it abbreviate | omits.

The material of the metal casing constituting the exhaust gas purifying apparatus of the present invention is not particularly limited as long as it is a metal having heat resistance, and specifically, metals such as stainless steel, aluminum, iron and the like can be mentioned.

As the shape of the metal casing constituting the exhaust gas purifying apparatus of the present invention, a clamshell shape, a downsizing shape or the like can be suitably used in addition to a substantially cylindrical shape.

First, the exhaust gas treatment body constituting the exhaust gas treatment apparatus will be described.
FIG. 3 is a perspective view schematically showing an example of the exhaust gas treating body constituting the exhaust gas purifying apparatus of the present invention.

The exhaust gas treatment body 130 shown in FIG. 3 is a honeycomb structure made of a columnar ceramic material in which a large number of cells 155 are arranged in parallel in the longitudinal direction with cell walls 156 interposed therebetween. In addition, any end portion of the cell 155 is sealed with a sealing material 158.

When any one end of the cell 155 is sealed, when viewed from one end of the exhaust gas treating body 130, the cell whose end is sealed and the cell that is not sealed are alternately arranged. It is desirable that

The cross-sectional shape obtained by cutting the exhaust gas treating body 130 in a direction perpendicular to the longitudinal direction is not particularly limited, and may be a substantially circular shape, a substantially elliptical shape, or a substantially polygonal shape such as a substantially triangular shape, a substantially rectangular shape, a substantially pentagonal shape, or a substantially hexagonal shape. It may be. Further, the exhaust gas treatment body 130 may be a collection of a plurality of exhaust gas treatment body units. In such a case, the cross-sectional shape of the exhaust gas treatment body unit constituting the exhaust gas treatment body 130 is based on a straight line and a curve. It may be configured.

The cross-sectional shape of the cell 155 constituting the exhaust gas treatment body 130 may be a substantially triangular shape, a substantially quadrangular shape, a substantially pentagonal shape, a substantially hexagonal shape or the like, or may be a substantially circular shape or a substantially elliptical shape. Further, the exhaust gas treating body 130 may be a combination of cells having a plurality of cross-sectional shapes.

The material constituting the exhaust gas treatment body 130 is not particularly limited, and non-oxides such as silicon carbide and silicon nitride, and oxides such as cordierite and aluminum titanate can be used.
Since these porous fired bodies are brittle materials, they are easily broken by a mechanical impact or the like. However, in the exhaust gas purifying apparatus of the present invention, the holding sealing material 120 is interposed around the side surface of the exhaust gas treatment body 130 and absorbs the impact, so that the exhaust gas treatment body 130 is cracked by mechanical shock or thermal shock. It can be prevented from occurring.

The exhaust gas treating body 130 is preferably a cordierite or silicon carbide porous fired body.
In the case of using cordierite, as shown in FIG. 1, the exhaust gas treatment body 130 is made of a single ceramic. However, in the case of using a silicon carbide material, as described later, the exhaust gas treatment body 130 The body 130 is not composed of a single ceramic, and a plurality of columnar ceramics are bonded and bonded together with an adhesive formed on the side surface.

When the exhaust gas treating body constituting the exhaust gas purifying apparatus of the present invention is a porous ceramic, the porosity of the porous ceramic is not particularly limited, but is preferably 35 to 60%.
If the porosity is less than 35%, the exhaust gas treating body may be clogged immediately. On the other hand, if the porosity exceeds 60%, the strength of the exhaust gas treating body is lowered and easily destroyed. Because there is.
The average pore diameter of the porous ceramic is preferably 5 to 30 μm.
If the average pore diameter is less than 5 μm, the PM may easily clog. On the other hand, if the average pore diameter exceeds 30 μm, the PM will pass through the pores and the PM cannot be repaired. It is because it may not function as.
The porosity and pore diameter can be measured by a conventionally known method using a mercury intrusion method, a scanning electron microscope (SEM), or the like.

Although the cell density in the cross section of the exhaust gas treating body constituting the exhaust gas purifying apparatus of the present invention is not particularly limited, the desirable lower limit is 31.0 / cm ² (200 / inch ² ), and the desirable upper limit is 93.9. Pieces / cm ² (600 pieces / inch ² ), the more desirable lower limit is 38.8 pieces / cm ² (250 pieces / inch ² ), and the more desirable upper limit is 77.5 pieces / cm ² (500 pieces / inch ^2). ).

The exhaust gas treating body constituting the exhaust gas purifying apparatus of the present invention may carry a catalyst for purifying exhaust gas, and the supported catalyst is preferably a noble metal such as platinum, palladium, rhodium, etc. Then, platinum is more desirable. In addition, as other catalysts, for example, alkali metals such as potassium and sodium, and alkaline earth metals such as barium can be used. These catalysts may be used alone or in combination of two or more. When these catalysts are supported, it is easy to burn and remove PM, and toxic exhaust gas can be purified.

Further, the catalyst may be supported on a catalyst support layer formed on the surface of the cell 155. The catalyst support layer is not particularly limited as long as it has a large specific surface area, and examples thereof include γ-alumina. By supporting the catalyst on the catalyst supporting layer, the contact area between the catalyst and the exhaust gas can be increased.

The exhaust gas treatment body constituting the exhaust gas purification apparatus of the present invention may be an integrally formed honeycomb structure made of cordierite or the like, or may be made of silicon carbide or the like, and has a large number of through holes. May be a collective honeycomb structure formed by bundling a plurality of columnar honeycomb fired bodies arranged in parallel in the longitudinal direction with partition walls interposed therebetween through an adhesive layer mainly containing ceramics.

In the exhaust gas treating body constituting the exhaust gas purifying apparatus of the present invention, the end of the cell may not be sealed without providing the cell with the sealing material. In this case, the exhaust gas treating body functions as a catalyst carrier that purifies harmful gas components such as CO, HC, or NOx contained in the exhaust gas by supporting a catalyst such as platinum.

In the exhaust gas treating body constituting the exhaust gas purifying apparatus of the present invention, an outer peripheral coat layer may be formed on the outer peripheral surface. When the outer peripheral coating layer is formed on the outer peripheral surface of the exhaust gas treating body, the outer peripheral portion of the exhaust gas treating body can be reinforced, the shape can be adjusted, and the heat insulation can be improved. In addition, the outer peripheral surface of the exhaust gas treatment body refers to a side surface portion of the exhaust gas treatment body that is columnar.

Next, the manufacturing method of the exhaust gas purification apparatus of the present invention will be described.

FIG. 4 is a perspective view schematically showing an example of the manufacturing method of the exhaust gas purifying apparatus of the present invention.
As shown in FIG. 4, the exhaust gas treating body and the holding sealing material constituting the exhaust gas purifying apparatus of the present invention are arranged along the circumference of the exhaust gas treating body 130 with the second main surface of the holding sealing material 120 inside. The main surface 122 of No. 2 and the exhaust gas treatment body 130 are wound so as to be in contact with each other, thereby forming a wound body 140. The holding sealing material 120 is the holding sealing material shown in FIG. 1, the first main surface is impregnated with the organic binder A, the second main surface is impregnated with the organic binder B, and the second sealing material 120 The main surface is in contact with the exhaust gas treating body 130.

Next, by accommodating the wound body 140 in the metal casing 110, the exhaust gas purifying apparatus of the present invention is obtained. The metal casing 110 is mainly made of a metal such as stainless steel, and the shape thereof may be a substantially cylindrical shape whose inner diameter at both ends is smaller than the inner diameter at the center as shown in FIG. May be substantially cylindrical.

As a method for accommodating the wound body 140 in the metal casing 110, for example, a press-fitting method (stuffing method) in which the exhaust gas treatment body 130 in which the holding sealing material 120 is disposed around to a predetermined position inside the metal casing 110 is press-fitted. A sizing method (swaging type) that compresses from the outer peripheral side so as to reduce the inner diameter of the metal casing 110, and a metal casing that is separable into parts of the first casing and the second casing, For example, a clamshell method in which the second casing is covered and sealed after the 140 is placed on the first casing. Moreover, the substantially cylindrical shape with a constant internal diameter may be sufficient.

The holding sealing material 120 accommodated in the metal casing 110 has a first main surface in contact with the metal casing 110, while the second main surface is in contact with the exhaust gas treating body 130.
In the manufacturing method of the exhaust gas purifying apparatus of the present invention, it is desirable to accommodate by a press-fitting method (stuffing method) from the viewpoints of productivity, airtightness, earthquake resistance, and the like.
When the wound body is accommodated in the metal casing by the press-fitting method (stuffing method), the inner diameter of the metal casing (the inner diameter of the portion accommodating the exhaust gas treatment body) is slightly smaller than the outer diameter of the wound body 140. Is desirable.

The exhaust gas purifying apparatus of the present invention may be composed of one holding sealing material, or may be composed of a plurality of holding sealing materials of two or more layers bonded to each other. It is particularly desirable that it is made of a material. When one holding sealing material is used as the holding sealing material of the exhaust gas purifying apparatus, there is no contact portion between the holding sealing materials, so that the inorganic fibers can be prevented from being damaged due to friction between the holding sealing materials. In addition, it is possible to prevent the holding sealing materials from being displaced during storage.
The method of joining a plurality of holding sealing materials is not particularly limited, and examples thereof include a method of sewing the holding sealing materials by sewing, a method of bonding the holding sealing materials with an adhesive tape or an adhesive, and the like. It is done.
Through these steps, the exhaust gas purification apparatus of the present invention is manufactured.

Below, the effect of the holding sealing material of this invention, the manufacturing method of this holding sealing material, an exhaust gas purification apparatus, and the manufacturing method of an exhaust gas purification apparatus is demonstrated.

(1) In the holding sealing material of the present invention, the first main surface of the holding sealing material impregnated with the organic binder A is relatively harder than the second main surface impregnated with the organic binder B, The coefficient of static friction with respect to the metal casing with which the first main surface is in contact is low and slippery. On the other hand, the second main surface that is in contact with the exhaust gas treating body is relatively soft compared to the first main surface, and therefore has a high coefficient of static friction with respect to the exhaust gas treating body and is difficult to slip. For this reason, when the holding sealing material around which the holding sealing material is wound is accommodated in the metal casing, the first main surface of the holding sealing material impregnated with the organic binder A slips with respect to the metal casing. It becomes easy and can be easily accommodated in a metal casing, and productivity improves. On the other hand, the second main surface of the holding sealing material impregnated with the organic binder B becomes less slippery with respect to the exhaust gas treating body, and when the holding sealing material wrapped with the holding sealing material is accommodated in the metal casing. The exhaust gas treating body and the holding sealing material are difficult to shift.

(2) In the manufacturing method of the holding sealing material of the present invention, the holding sealing material having the above configuration can be easily manufactured.

(3) In the exhaust gas purifying apparatus of the present invention, since a holding sealing material made of a mat having a rectangular shape in plan view including inorganic fibers is interposed between the exhaust gas treating body and the metal casing, the exhaust gas is prevented from leaking. The organic binder A impregnated on the first main surface of the holding sealing material makes the first main surface of the holding sealing material slippery with respect to the metal casing, and the organic binder B allows the second main surface to slide. Since the surface is less likely to slip with respect to the exhaust gas treatment body, the workability at the time of accommodation is improved, and the exhaust gas treatment body is not easily displaced.

(4) Furthermore, in the exhaust gas purifying apparatus of the present invention, since the frictional resistance between the metal casing and the holding sealing material is small at the time of accommodation, it is possible to prevent the inorganic fibers constituting the holding sealing material from being damaged during the housing operation. Can do.

(5) Moreover, in the exhaust gas purifying apparatus of the present invention, the organic binder A is burned out by the exhaust gas flowing through the exhaust gas treating body constituting the exhaust gas purifying apparatus. When the organic binder A is burned out, the holding sealing material is easily expanded, and the exhaust gas treating body can be stably held.

FIGS. 5A and 5B are schematic diagrams showing an example of a method for measuring the coefficient of static friction.
As shown in FIG. 5 (a), a stainless steel plate 210 that looks like a metal casing is sandwiched between two holding sealing materials 120 so as to be in contact with the first main surface 121, and both sides thereof are sandwiched between fixing members 220. It arrange | positions so that one fixing member may contact | connect a vertical wall. Next, N force is applied to the fixing member 220 not in contact with the vertical wall in the vertical direction toward the vertical wall. With the N force applied to the fixing member, the stainless steel plate 210 is pulled with a force F in a direction parallel to the longitudinal direction of the stainless steel plate 210, and F at the moment when the stainless steel plate 210 starts to move is measured. The static friction coefficient between the first main surface 121 and the metal casing is obtained.

As shown in FIG. 5 (b), the ceramic plate 211 that looks like an exhaust gas treating body is sandwiched between two holding sealing materials 120 so as to be in contact with the second main surface 122, and further, both sides thereof are sandwiched between fixing members 220, Any one of the fixing members 220 is disposed in contact with the vertical wall. Next, N force is applied to the fixing member 220 not in contact with the vertical wall in the direction toward the vertical wall. With the N force applied to the fixing member 220 that is not in contact with the vertical wall, the ceramic plate 211 is pulled with the F force in a direction parallel to the longitudinal direction of the ceramic plate 211, and the F at the moment when the ceramic plate 211 starts to move. And the coefficient of static friction between the second main surface 122 of the holding sealing material 120 and the exhaust gas treating body is obtained.

Examples in which the present invention is disclosed more specifically are shown below. In addition, this invention is not limited only to these Examples.

Example 1
(A) Mat Preparation Step First, a mat for the holding sealing material was prepared by the following procedure.
(A-1) Spinning Step Inorganic fibers after firing with respect to a basic aluminum chloride aqueous solution prepared so that the Al content is 70 g / l and Al: Cl = 1: 1.8 (atomic ratio) A silica sol was blended so that the composition ratio in Al ₂ O ₃ : SiO ₂ = 72: 28 (weight ratio) was added, and an organic polymer (polyvinyl alcohol) was added in an appropriate amount to prepare a mixed solution.
The obtained mixed solution was concentrated to obtain a spinning mixture, and the spinning mixture was spun by a blowing method to prepare an inorganic fiber precursor having an average fiber diameter of 5.1 μm.

(A-2) Compression step The inorganic fiber precursor obtained in the step (a-1) was compressed to produce a continuous sheet-like material.

(A-3) Needle punching process The needle punching process body was produced by performing a needle punching process continuously on the sheet-like material obtained in the above-mentioned process (a-2) under the following conditions.
First, a needle board to which needles were attached at a density of 21 pieces / cm ² was prepared. Next, the needle board is disposed above the one surface of the sheet-like material, and the needle board is moved up and down once along the thickness direction of the sheet-like material to perform needle punching treatment. Was made. At this time, the needle was penetrated until the barb formed at the tip of the needle completely penetrated the surface on the opposite side of the sheet-like material.

(A-4) Firing step Inorganic fiber containing 72 parts by weight and 28 parts by weight of alumina and silica by continuously firing the needle punched body obtained in the step (a-3) at a maximum temperature of 1250 ° C. The baked sheet-like material which consists of was manufactured. The average fiber diameter of the inorganic fibers was 5.1 μm, and the minimum value of the inorganic fiber diameter was 3.2 μm. The alumina fiber holding sealing material thus obtained had a bulk density of 0.15 g / cm ³ and a basis weight of 1400 g / m ² .

(A-5) Cutting step The fired sheet-like material obtained in the step (a-4) was cut to produce a cut sheet-like material.

(B) Impregnation step (b-1) Organic binder adjustment step A latex (Nipol LX814 manufactured by Nippon Zeon Co., Ltd., hereinafter referred to as Latex 1) in which acrylic rubber having a glass transition temperature (Tg) of 25 ° C. is dispersed in water is used. By diluting with water, an organic binder-containing liquid having a solid content concentration of 1% by weight was prepared. In this embodiment, the latex 1 is an organic binder A. In addition, by using a latex (Nipol LX811H manufactured by Nippon Zeon Co., Ltd., hereinafter referred to as latex 2) in which acrylic rubber having a glass transition temperature (Tg) of 1 ° C. is dispersed in water, the solid content concentration is reduced by diluting with water. A 1% by weight organic binder-containing liquid was prepared. In this embodiment, the latex 2 is the organic binder B.
(B-2) Organic Binder Spraying Step Next, the organic binder A-containing liquid was spray coated on one main surface of the mat so that the amount of the organic binder A attached was 1 part by weight per 100 parts by weight of the inorganic fibers. The main surface impregnated with the organic binder A becomes the first main surface.
Next, the organic binder B-containing liquid was spray-coated on the main surface opposite to the first main surface so that the adhesion amount of the organic binder B was 1 part by weight per 100 parts by weight of the inorganic fibers. The main surface impregnated with the organic binder B becomes the second main surface.

(C) Drying step Next, the mat to which the organic binder was adhered was heated and dried with hot air at 130 ° C. to obtain a mat impregnated with the organic binder.

(D) Cutting process The mat obtained in this way has a plan view dimension with a total length of 307 mm × 114 mm, a length L of 20 mm, and a width W of 38 mm. The production of the holding sealing material was completed by cutting so as to form a concave portion that fits with the convex portion.
The thickness of the holding sealing material was 17.4 mm.

(Comparative Example 1)
(B) A holding sealing material was produced in the same manner as in Example 1 except that the organic binder B was changed to latex 1 in the impregnation step.

(Comparative Example 2)
(B) A holding sealing material was produced in the same manner as in Example 1 except that the organic binder A was changed to latex 2 in the impregnation step.

(Comparative Example 3)
(B) A holding sealing material was produced in the same manner as in Example 1 except that the organic binder B was changed to latex 1 and the organic binder A was changed to latex 2 in the impregnation step.

(Determination of the amount of organic binder impregnation)
Regarding the amount of impregnation of the organic binder, the holding sealing materials of Example 1 and Comparative Examples 1 to 3 impregnated with the organic binder were cut into a size of 100 mm × 100 mm, and the cut sample was divided into two equal parts in the thickness direction. Thereafter, the weight loss was measured by heating at 700 ° C. in an oxidizing atmosphere, and the impregnation amount (g) of the organic binder with respect to 100 g of inorganic fibers was calculated from the result. The impregnation amount of the organic binder with respect to 100 parts by weight of the inorganic fibers of the holding sealing materials of Example 1 and Comparative Examples 1 to 3 was 1 part by weight on each of the first main surface and the second main surface.

The holding sealing material obtained in Example 1 and Comparative Examples 1 to 3 was wound around the exhaust gas treatment body so that the second main surface was in contact with the exhaust gas treatment body to obtain a wound body. This wound body was accommodated in the metal casing by a press-fitting method so that the first main surface was in contact with the metal casing, and the accommodating property and stability were confirmed.
In the wound body wound with the holding sealing material of Example 1, the glass transition temperature of the organic binder A impregnated on the first main surface is higher than the glass transition temperature of the organic binder B impregnated on the second main surface. Since it was high, the first main surface was harder than the second main surface. Therefore, the coefficient of static friction between the holding sealing material and the casing is low, and the holding sealing material is slippery and easy to accommodate. In addition, the second main surface is softer than the first main surface, the coefficient of static friction between the holding sealing material and the exhaust gas treatment body is high, and the holding sealing material is not slippery and is held during storage. The sealing material and the exhaust gas treating body did not shift.
In the wound body around which the holding sealing material of Comparative Example 1 is wound, the glass transition temperature of the organic binder A impregnated on the first main surface is the same as the glass transition temperature of the organic binder B impregnated on the second main surface. Therefore, the hardness of the first main surface and the second main surface was the same. Furthermore, since the glass transition temperature of the organic binder B is 5 ° C. or higher, the second main surface is too hard, and the holding sealing material and the exhaust gas treating body are easily misaligned during housing.
In the wound body around which the holding sealing material of Comparative Example 2 is wound, the glass transition temperature of the organic binder A impregnated on the first main surface is the same as the glass transition temperature of the organic binder B impregnated on the second main surface. Therefore, the hardness of the first main surface and the second main surface was the same. Furthermore, since the glass transition temperature of the organic binder A is less than 5 ° C., the first main surface is too soft, and a large force is required at the time of accommodation, and the accommodation is not easy.
In the wound body around which the holding sealing material of Comparative Example 3 is wound, the glass transition temperature of the organic binder A impregnated on the first main surface is higher than the glass transition temperature of the organic binder B impregnated on the second main surface. Therefore, the first main surface was too soft and the second main surface was too hard. For this reason, the coefficient of static friction between the holding sealing material and the metal casing is large, and the housing is not easy. Furthermore, the coefficient of static friction between the holding sealing material and the exhaust gas treating body is small, and the holding sealing material and the exhaust gas treating body are liable to shift after housing. Thus, it turned out that the holding sealing material which concerns on Example 1 is superior to the holding sealing material which concerns on Comparative Examples 1-3 from a viewpoint of the ease of accommodation operation | work and prevention of the shift | offset | difference of a gas processing body. did.

DESCRIPTION OF SYMBOLS 100 Exhaust gas purification apparatus 110 Metal casing 120 Holding sealing material 121 1st main surface 122 2nd main surface 130 Exhaust gas processing body

Claims (9)

Used in an exhaust gas purification device comprising an exhaust gas treatment body, a metal casing that houses the exhaust gas treatment body, and a holding sealing material made of inorganic fibers disposed between the exhaust gas treatment body and the metal casing Holding sealing material,
The holding sealing material includes a first main surface in contact with the metal casing and a second main surface in contact with the exhaust gas treating body,
The first main surface and the second main surface are impregnated with an organic binder,
The holding sealing material, wherein the glass transition temperature of the organic binder A impregnated in the first main surface is higher than the glass transition temperature of the organic binder B impregnated in the second main surface. The holding sealing material according to claim 1, wherein the glass transition temperature of the organic binder A is 5 ° C or higher and 50 ° C or lower, and the glass transition temperature of the organic binder B is -50 ° C or higher and lower than 5 ° C. The organic binder A is impregnated in a predetermined region including the first main surface, and the organic binder B is impregnated in a predetermined region including the second main surface,
The impregnation amount of the organic binder A impregnated in a predetermined region including the first main surface is 0.2 to 12.0 parts by weight with respect to 100 parts by weight of the inorganic fiber, and the second main surface The holding sealing material according to claim 1 or 2, wherein an impregnation amount of the organic binder B impregnated in a predetermined region containing is 0.2 to 12.0 parts by weight with respect to 100 parts by weight of the inorganic fibers. The holding sealing material according to claim 3, wherein the total impregnation amount of the organic binder A and the organic binder B is 0.5 to 3.0 parts by weight with respect to 100 parts by weight of the inorganic fibers. The holding sealing material according to any one of claims 1 to 4, wherein at least an acrylic resin is contained in the organic binder A and the organic binder B. The said inorganic fiber is comprised from at least 1 type selected from the group which consists of an alumina fiber, a silica fiber, an alumina silica fiber, a mullite fiber, a biosoluble fiber, and a glass fiber. Holding sealing material. A mat preparation step of preparing a mat for a holding sealing material made of inorganic fibers subjected to needle punching treatment;
An impregnation step of spraying droplets of an organic binder-containing liquid containing the organic binder A against the first main surface of the mat;
The method for producing a holding sealing material according to claim 1, further comprising a drying step of drying the mat containing the organic binder-containing liquid. The method for manufacturing a holding sealing material according to claim 7, further comprising a step of spraying droplets of the organic binder-containing liquid containing the organic binder B on the second main surface of the mat in the impregnation step. A metal casing;
An exhaust gas treating body housed in the metal casing;
An exhaust gas purification apparatus comprising a holding sealing material wound around the exhaust gas treatment body and disposed between the exhaust gas treatment body and the metal casing,
The exhaust gas purification apparatus, wherein the holding sealing material is the holding sealing material according to any one of claims 1 to 6.

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