JP2020204303A - Mat material, exhaust emission control device, and exhaust pipe with mat material - Google Patents

Abstract

To provide a mat material having a high heat insulation property.SOLUTION: A mat material 10 made of inorganic fibers, includes an infrared reflection material and infrared absorption material which have a particle size of 1-100 μm. If the particle size of the infrared reflection material and infrared absorption material is within the above range, an infrared absorption rate and infrared reflection efficiency become excellent, and a solid heat transfer rate comes within an appropriate range.SELECTED DRAWING: Figure 1

Description

The present invention relates to a mat material, an exhaust gas purifying device, and an exhaust pipe with a mat material.

Conventionally, an internal combustion engine using gasoline or light oil as a fuel has been used for more than 100 years as a power source for vehicles, especially automobiles. However, it is becoming increasingly problematic that exhaust gas is harmful to health and the environment. Therefore, recently, an exhaust gas purification catalytic converter that removes harmful components such as CO, NOx, and HC contained in the exhaust gas, a DPF (Diesel Particulate Filter) that removes PM (particulate matter), etc. Various exhaust gas purification devices have been proposed.
An ordinary exhaust gas purifying device includes an exhaust gas treatment body (catalyst carrier), a metal casing that covers the outer periphery of the catalyst carrier, and a holding material arranged between them. Further, a catalyst such as platinum is supported on the exhaust gas treated body.

In order for the catalyst carried on the exhaust gas treatment body to decompose harmful components in the exhaust gas, it is necessary to reach a predetermined activation temperature.
The exhaust gas emitted from the internal combustion engine has a high temperature, and the catalyst reaches the active temperature by being heated by the exhaust gas.
The exhaust gas reaches the exhaust gas purification device through the exhaust pipe, but in order to quickly reach the active temperature of the catalyst, it is desirable that the heat loss at this time is as small as possible.
Further, in order to maintain the active temperature of the catalyst, it is desirable that the heat loss from the exhaust gas purification device is as small as possible.

In order to prevent such heat loss, Patent Document 1 describes a catalyst carrier (exhaust gas treatment body) formed in a tubular shape, a casing accommodating the catalyst carrier, and the catalyst wrapped around the catalyst carrier. The holding material used for a catalytic converter (exhaust gas treatment body) including a holding material (mat material) interposed in a gap between a carrier and the casing, which is an inorganic fiber, red iron oxide, titanium oxide, and zinc oxide. Also disclosed is the use of a catalyst converter carrier characterized by containing at least one insulating filler selected from silicon carbide.

Japanese Unexamined Patent Publication No. 2003-293753

Since the holding material for the catalytic converter described in Patent Document 1 contains a heat insulating filler, it is possible to prevent the release of heat to some extent by using this. However, the heat insulating performance was not sufficient.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a mat material having high heat insulating performance.

That is, the mat material of the present invention is a mat material made of inorganic fibers, and is characterized by containing an infrared reflector and / or an infrared absorber having a particle size of 1 to 100 μm.

The mat material of the present invention includes an infrared reflector and / or an infrared absorber having a particle size of 1 to 100 μm.
When the particle size of the infrared reflector and / or the infrared absorber is in the above range, the infrared absorption rate and / or the infrared reflection efficiency is good, and the solid heat transfer rate is also in an appropriate range.
Therefore, the mat material of the present invention has high heat insulating performance.
If the particle size is less than 1 μm, the volume becomes small and the infrared reflectance and / or the infrared absorption rate becomes low. Therefore, it becomes difficult to obtain sufficient heat insulating performance.
When the particle size exceeds 100 μm, the solid heat transfer rate becomes high, and heat is easily transferred from the heat receiving surface side to the opposite surface of the mat material. Therefore, it becomes difficult to obtain sufficient heat insulating performance. In addition, the dispersibility becomes poor and the distance between the particles becomes wide. Therefore, the proportion of infrared rays that hit the particles becomes small. As a result, infrared rays easily pass from the heat receiving surface of the mat material to the opposite surface, and the heat insulating performance is deteriorated.

In the present specification, even if the particles are composed of the same substance as the infrared reflector and / or the infrared absorber, if the particle diameter is less than 1 μm, the particles are treated as mere inorganic particles.

Further, since the mat material of the present invention contains an infrared reflector and / or an infrared absorber having a particle size of 1 to 100 μm, it adheres to the inorganic fibers of the mat material and forms irregularities on the surface of the inorganic fibers. Therefore, the frictional force between the inorganic fibers of the mat material is improved. As a result, the surface pressure of the mat material is improved.

The mat material of the present invention is a needle punching mat material, and it is desirable that the SUS plate surface temperature is 322 to 338 ° C. when the temperature of the hot plate is 800 ° C. in the following heat insulation performance measurement test. Such a mat material has sufficiently high heat insulating performance.
Insulation performance measurement test:
A test piece is cut out from a mat material with a thickness of 7 mm, a spacer is placed on the heat insulating block, a hot plate tester with a hot platen placed on the spacer is prepared, and the hot plate tester is placed on the hot plate of the hot plate tester. , The test piece and the SUS plate with a thickness of 1.5 mm are stacked in order, the heating plate is heated to a predetermined temperature, and 40 minutes after the temperature of the heating plate reaches the predetermined temperature, the surface of the SUS plate The temperature is measured and used as the SUS plate surface temperature.

The mat material of the present invention is a papermaking mat material, and it is desirable that the SUS surface temperature is 294 to 327 ° C. when the hot plate temperature is 800 ° C. in the following heat insulation performance measurement test. Such a mat material has sufficiently high heat insulating performance.
Insulation performance measurement test:
A test piece is cut out from a mat material with a thickness of 7 mm, a spacer is placed on the heat insulating block, a hot plate tester with a hot platen placed on the spacer is prepared, and the hot plate tester is placed on the hot plate of the hot plate tester. , The test piece and the SUS plate with a thickness of 1.5 mm are stacked in order, the heating plate is heated to a predetermined temperature, and 40 minutes after the temperature of the heating plate reaches the predetermined temperature, the surface of the SUS plate The temperature is measured and used as the SUS plate surface temperature.

In the mat material of the present invention, it is desirable that the infrared reflector is composed of at least one group consisting of titanium oxide, iron oxide, zirconium oxide, zinc oxide and aluminum oxide.
These compounds have high infrared reflectance and are suitable as infrared reflectors.

In the mat material of the present invention, it is desirable that the infrared absorber is made of silicon carbide.
Silicon carbide has a high infrared absorption rate and is suitable as an infrared absorber.

In the mat material of the present invention, the ratio of the weight of the inorganic fiber to the total weight of the infrared reflector and the infrared absorber is the weight of the inorganic fiber: the total weight of the infrared reflector and the infrared absorber = 100: 0. .5 to 100: 200 is desirable.
When the ratio of the total weight of the infrared reflector and the infrared absorber is less than the above range, the amount of infrared reflection and the amount of infrared absorption are reduced due to the small content of the infrared reflector and the infrared absorber. As a result, it becomes difficult to obtain sufficient heat insulating performance.
When the ratio of the total weight of the infrared reflector and the infrared absorber exceeds the above range, the infrared reflector and the infrared absorber are likely to fall off from the fiber.

It is desirable that the mat material of the present invention further contains inorganic particles having a particle size of less than 1 μm.
Such inorganic particles adhere to the inorganic fibers of the mat material and form irregularities on the surface of the inorganic fibers. Therefore, the frictional force between the inorganic fibers of the mat material is improved. As a result, the surface pressure of the mat material is improved.

It is desirable that the mat material of the present invention contains an organic binder.
When the mat material of the present invention contains an organic binder, it is possible to prevent the infrared reflector and / or the infrared absorber from falling off from the inorganic fiber.

The mat material of the present invention may be a three-dimensional molded product.
That is, it may be a mat material formed so as to maintain a predetermined shape.
When the mat material of the present invention is a three-dimensional molded product that matches the shape to be arranged, wrinkles and the like are suppressed when the mat material of the present invention is arranged, and the adhesion is further improved. When the adhesion between the mat material and the object to be arranged is high, gaps are less likely to occur between the mat material and the object to be arranged, so that heat can be suppressed from being released from these gaps. As a result, the heat insulating property is improved.

The exhaust gas purification device of the present invention comprises an exhaust gas treatment body, a metal casing accommodating the exhaust gas treatment body, and a mat material arranged between the exhaust gas treatment body and the metal casing and holding the exhaust gas treatment body. It is an exhaust gas purifying device provided, and the mat material is the mat material of the present invention.

As described above, the mat material of the present invention has high heat insulating performance.
Therefore, in the exhaust gas purification device using the mat material of the present invention, the heat of the exhaust gas that has reached the exhaust gas treatment body is not easily released to the outside.

The exhaust pipe with a mat material of the present invention is an exhaust pipe with a mat material including an exhaust pipe, a mat material arranged so as to cover the exhaust pipe, and a metal cover arranged outside the mat material. The mat material is the mat material of the present invention.

As described above, the mat material of the present invention has high heat insulating performance.
Therefore, in the exhaust pipe with a mat material using the mat material of the present invention, the heat of the gas passing through the exhaust pipe is not easily released to the outside.

FIG. 1 is a perspective view schematically showing an example of a mat material according to the present invention. FIG. 2 is a cross-sectional view schematically showing a heat insulating performance test of a mat material. FIG. 3 is a cross-sectional view schematically showing an example of an exhaust gas purification device including the mat material of the present invention. FIG. 4A is a perspective view schematically showing an example of an exhaust gas treatment body constituting the exhaust gas purification device of the present invention. FIG. 4B is a cross-sectional view taken along the line AA of FIG. 4A. FIG. 5 is a cross-sectional view schematically showing an example of an exhaust pipe with a matte material provided with the matte material of the present invention. 6 (a) to 6 (e) are SEM images of the inorganic fibers of the mat material according to Examples 1-1 to 1-4 and Comparative Example 1-2, respectively. 7 (a) to 7 (d) are SEM images of the inorganic fibers of the mat material according to Examples 2-1 to 2-4, respectively.

(Detailed description of the invention)
Hereinafter, the mat material of the present invention will be specifically described. However, the present invention is not limited to the following configurations, and can be appropriately modified and applied without changing the gist of the present invention. It should be noted that a combination of two or more of the individual preferred configurations of the present invention described below is also the present invention.

The mat material according to the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view schematically showing an example of a mat material according to the present invention.
As shown in FIG. 1, the mat material 10 has a rectangular shape in a plan view, and when the mat material 10 is wound around an object, the mat material 10 is attached to one end 11 of the mat material 10 so that the ends fit each other. A convex portion 11a is provided, and a concave portion 12a is provided at the other end portion 12.
When such a convex portion 11a and a concave portion 12a are provided, the sealing property is improved when the mat material 10 is arranged in the exhaust gas purification device described later.
The mat material of the present invention does not have to have a convex portion and a concave portion at the end portion of the mat material.

The mat material 10 includes an infrared reflector and / or an infrared absorber having a particle size of 1 to 100 μm.
Further, it is desirable that the particle size of the infrared reflector and / or the infrared absorber is 1 to 10 μm.
When the particle size of the infrared reflector and / or the infrared absorber is in the above range, the infrared absorption rate and / or the infrared reflection efficiency is good, and the solid heat transfer rate is also in an appropriate range.
Therefore, the mat material of the present invention has high heat insulating performance.
If the particle size is less than 1 μm, the volume becomes small and the infrared reflectance and / or the infrared absorption rate becomes low. Therefore, it becomes difficult to obtain sufficient heat insulating performance.
When the particle size exceeds 100 μm, the solid heat transfer rate becomes high, and heat is easily transferred from the heat receiving surface side to the opposite surface of the mat material. Therefore, it becomes difficult to obtain sufficient heat insulating performance. In addition, the dispersibility becomes poor and the distance between the particles becomes wide. Therefore, the proportion of infrared rays that hit the particles becomes small. As a result, infrared rays easily pass from the heat receiving surface side to the opposite surface of the mat material, and the heat insulating performance deteriorates.

In the mat material 10, the ratio of the weight of the inorganic fiber to the total weight of the infrared reflector and the infrared absorber is as follows: weight of the inorganic fiber: total weight of the infrared reflector and the infrared absorber = 100: 0.5 to It is preferably 100: 200, and more preferably 100: 10 to 100: 100.
When the ratio of the total weight of the infrared reflector and the infrared absorber is less than the above range, the amount of infrared reflection and the amount of infrared absorption are reduced due to the small content of the infrared reflector and the infrared absorber. As a result, it becomes difficult to obtain sufficient heat insulating performance.
When the ratio of the total weight of the infrared reflector and the infrared absorber exceeds the above range, the infrared reflector and the infrared absorber are likely to fall off from the fiber.

In the mat material 10, the infrared reflector is preferably composed of at least one of a group consisting of titanium oxide, iron oxide, zirconium oxide, zinc oxide and aluminum oxide.
These compounds have high infrared reflectance and are suitable as infrared reflectors.

It is more desirable that the infrared reflector is titanium oxide. When the infrared reflector is titanium oxide, its particle size is preferably 1 to 10 μm.

In the mat material 10, the infrared absorber is preferably made of silicon carbide.
Silicon carbide has a high infrared absorption rate and is suitable as an infrared absorber.

In the mat material 10, two or more types of infrared reflectors and infrared absorbers may be used in combination.

The mat material 10 may be a needle punching mat material or a papermaking mat material.

When the mat material 10 is a needle punching mat material, the average length of the inorganic fibers is preferably 1 to 150 mm, more preferably 10 to 80 mm.
If the average fiber length of the inorganic fibers is less than 1 mm, the fiber lengths of the inorganic fibers are too short, so that the inorganic fibers are not sufficiently entangled with each other, the strength of the mat material is difficult to obtain, and the shape retention of the mat material is improved. It tends to decrease.
If the average fiber length of the fibers exceeds 150 mm, the fiber lengths of the fibers are too long, so that the number of fibers constituting the mat material is reduced, and the denseness is lowered.

When the mat material 10 is a papermaking mat material, it is desirable that the average fiber length of the inorganic fibers is 0.1 to 20 mm.
If the average fiber length of the inorganic fiber is less than 0.1 mm, the fiber length of the inorganic fiber is too short, and the shape retention as a mat material is lowered. Further, when a fiber aggregate is formed as a mat material, suitable entanglement does not occur between the inorganic fibers, and it becomes difficult to obtain a sufficient surface pressure.
If the average fiber length of the inorganic fibers exceeds 20 mm, the fiber length of the inorganic fibers is too long, and the inorganic fibers in the slurry solution in which the inorganic fibers are dispersed in water in the papermaking process become too entangled with each other. When this is done, the inorganic fibers tend to accumulate non-uniformly, and the shear strength also tends to decrease.

In the measurement of the inorganic fiber length, tweezers are used in both the needle punching method and the manufacturing method to extract the inorganic fiber from the mat material so as not to break, and the fiber length is measured using an optical microscope.
In the present specification, the average fiber length means the average length obtained by extracting 300 inorganic fibers from the mat material and measuring the fiber length. If the inorganic fibers cannot be removed from the mat material without breaking, degreasing the mat material and putting the degreased mat material into water to loosen the entanglement between the inorganic fibers and prevent the inorganic fibers from breaking. It is good to collect.

In the mat 10, the average fiber diameter of the inorganic fibers is preferably 1 to 20 μm, more preferably 2 to 15 μm, and even more preferably 3 to 10 μm.
When the average fiber diameter of the inorganic fibers is less than 1 μm, the strength is weak and the inorganic fibers are easily cut by impact or the like.
When the average fiber diameter of the inorganic fiber exceeds 20 μm, the fiber diameter is too large and the Young's modulus of the inorganic fiber itself becomes high, and the flexibility of the mat material tends to be low.

Examples of the inorganic fiber include alumina fiber, alumina-silica fiber, silica fiber, glass wool, rock wool and the like. Of these, alumina-silica fibers are desirable.
These inorganic fibers have high heat resistance, and the mat material formed of such inorganic fibers does not easily change its shape due to temperature changes.

Further, when the inorganic fiber is an alumina-silica fiber, the composition ratio of alumina to silica is preferably alumina (Al ₂ O ₃ ): silica (SiO ₂ ) = 60: 40 to 80:20 in terms of weight ratio. , Alumina (Al ₂ O ₃ ): Silica (SiO ₂ ) = 70: 30 to 74: 26.

In the mat material 10, two or more kinds of inorganic fibers may be used in combination.

It is desirable that the mat material 10 further contains inorganic particles having a particle size of less than 1 μm.
The particle size of the inorganic particles is preferably 0.001 μm or more, and more preferably 0.01 μm or more.
Such inorganic particles adhere to the inorganic fibers of the mat material 10 and form irregularities on the surface of the inorganic fibers. Therefore, the frictional force between the inorganic fibers of the mat material 10 is improved. As a result, the surface pressure of the mat material 10 is improved.

Examples of the substance constituting such inorganic particles include aluminum oxide, silicon oxide, zirconium oxide and the like.

When the mat material 10 contains inorganic particles, the ratio of the weight of the inorganic fibers to the weight of the inorganic particles is preferably the weight of the inorganic fibers: the weight of the inorganic particles = 100: 0.1 to 100:10.

It is desirable that the mat material 10 further contains an organic binder.
When the mat material 10 contains an organic binder, it is possible to prevent the inorganic fibers from scattering from the mat material and the inorganic particles and the infrared reflector and / or the infrared absorber from falling off from the inorganic fibers.

Examples of such an organic binder include water-soluble or water-dispersed organic polymers such as acrylic resin, acrylate-based latex, rubber-based latex, carboxymethyl cellulose or polyvinyl alcohol, thermoplastic resins such as styrene resin, and heat of epoxy resin and the like. Examples include curable resin.
Two or more of these organic binders may be used in combination.

As described above, since the mat material 10 contains an infrared reflector and / or an infrared absorber having a particle size of 1 to 100 μm, it has high heat insulating performance.
Further, the mat material 10 may be a needle punching mat material or a papermaking mat material, but the heat insulating performance differs depending on the manufacturing method.

When the mat material 10 is a needle punching mat material, it is desirable that the SUS surface temperature is 322 to 338 ° C. when the temperature of the hot plate is 800 ° C. in the following heat insulation performance measurement test.
When the mat material 10 is a papermaking mat material, it is desirable that the SUS surface temperature is 294 to 327 ° C. when the hot plate temperature is 800 ° C. in the following heat insulation performance measurement test.
It can be said that such a mat material 10 has sufficiently high heat insulating performance.

Here, the heat insulation performance measurement test will be described with reference to the drawings.
FIG. 2 is a cross-sectional view schematically showing a heat insulating performance test of a mat material.
As shown in FIG. 2, in the heat insulation performance measurement test, first, the test piece 15 is cut out from a mat material having a thickness of 7 mm.
Next, a hot plate testing machine 20 in which the spacer 22 is arranged on the heat insulating block 21 and the hot plate 23 is arranged on the spacer 22 is prepared.
Next, the test piece 15 and the SUS plate 30 having a thickness of 1.5 mm are sequentially stacked on the heat plate 23 of the heat plate tester 20.
Next, the heating plate 23 is heated to a predetermined temperature, and the surface of the SUS plate 30 40 minutes after the temperature of the heating plate 23 reaches the predetermined temperature (indicated by the reference numeral “P” in FIG. 2). Position) temperature is measured and used as the SUS plate surface temperature.

Next, the method for producing the mat material of the present invention will be described.
The mat material of the present invention may be produced by a needle punching method or a papermaking method.

The method for producing the mat material of the present invention by the needle punching method and the method for producing the mat material by the papermaking method will be described below.

(Manufacturing method of mat material by needle punching method)
(1) Inorganic Fiber Precursor Preparation Step An inorganic fiber precursor is prepared by spinning a spinning mixture containing raw materials for inorganic fibers such as alumina and silica by a blowing method.

(2) Firing Step Subsequently, the inorganic fiber precursor is compressed to prepare a continuous sheet having a predetermined size, which is subjected to a needle punching treatment and then a calcining treatment to obtain the alumina fiber. Prepare an aggregate of inorganic fibers.
The density of needle punching is preferably 0.1 to 30 pieces / cm ² .

(3) Infrared Reflector and / or Infrared Absorber Applying Step Subsequently, a solution containing an infrared reflector and / or an infrared absorber having a particle size of 1 to 100 μm is prepared, and the solution is attached to the inorganic fiber aggregate. .. As a result, the infrared reflector and / or the infrared absorber having a particle size of 1 to 100 μm is attached to the inorganic fiber and then dried.
If necessary, inorganic particles and an organic binder may be added to the solution containing the infrared reflector and / or the infrared absorber.

The mat material of the present invention can be prepared through the above steps.

(Manufacturing method of mat material by papermaking method)
(1) Mixed Liquid Preparation Step First, the inorganic fiber, the infrared reflector and / or the infrared absorber having a particle diameter of 1 to 100 μm, the inorganic particles, the organic binder, and water are mixed and stirred with a stirrer. To prepare the mixture.
As each material used in this step, it is desirable to use each material described in the above description of the mat material of the present invention.

(2) Dehydration Step Next, after the mixed solution is poured into a molding machine having a mesh for filtration formed on the bottom surface, the water in the mixed solution is dehydrated through the mesh to prepare a raw material sheet.

(3) Heat and pressurization step Next, the raw material sheet is heated and pressurized to prepare a mat material. Further, at the time of heating and pressurizing, a heat treatment may be performed in which hot air is ventilated through the raw material sheet to dry the raw material sheet, or a wet state may be obtained without the heat treatment.
In the case of heat treatment, it is desirable that the heating temperature and the hot air temperature are 100 to 250 ° C. in order to prevent deterioration due to heat of the organic binder. In the range of 100 to 250 ° C., moisture can be removed from the mat material while suppressing deterioration of the organic binder. If the heating temperature or hot air temperature is less than 100 ° C., the temperature is not transmitted to the central portion of the mat material, and the drying time becomes long. Further, if the temperature exceeds 250 ° C., the organic binder is deteriorated and the binding force between the fibers is reduced, so that the thickness of the mat material cannot be controlled.

The mat material of the present invention can be produced through the above steps.

Further, the mat material of the present invention may be a three-dimensional molded product that is three-dimensionally molded according to the shape to be arranged.
When the mat material of the present invention is a three-dimensional molded product that matches the shape of the object to be arranged, wrinkles and the like are suppressed and the adhesion is further improved when the mat material of the present invention is arranged. When the adhesion between the mat material and the object to be arranged is high, gaps are less likely to occur between the mat material and the object to be arranged, so that heat can be suppressed from being released from these gaps. As a result, the heat insulating property is improved.
The mat material which is such a three-dimensional molded product can be manufactured by a conventional method for manufacturing a three-dimensional molded mat.

The use of the mat material of the present invention is not particularly limited as long as it is used as a mat material that is required to have heat insulating properties.
When the mat material of the present invention is used, the mat material may be wrapped around an object or simply arranged.
Examples of such applications of the mat material of the present invention include applications as a mat material used in an exhaust gas purification device and applications as a mat material used in an exhaust pipe with a mat material.

An exhaust gas purification device including the mat material of the present invention, which is an example of the method of using the mat material of the present invention, will be described.
The exhaust gas purification device provided with the mat material of the present invention is also the exhaust gas purification device of the present invention.
FIG. 3 is a cross-sectional view schematically showing an example of an exhaust gas purification device including the mat material of the present invention.

As shown in FIG. 3, the exhaust gas purification device 100 is arranged between the exhaust gas treatment body 40, the metal casing 50 accommodating the exhaust gas treatment body 40, and the exhaust gas treatment body 40 and the metal casing 50, and the exhaust gas treatment body 40. The mat material 10 for holding the above is provided.
Further, the mat material 10 is the mat material of the present invention.

Normally, exhaust gas at about 800 ° C. flows into the exhaust gas purification device 100 (in FIG. 3, the exhaust gas is indicated by the symbol “G” and the gas flow is indicated by an arrow), and the exhaust gas treatment body 40 is also heated to about 800 ° C. Will be done.
In the exhaust gas purification device 100, the mat material 10 is in contact with the exhaust gas treatment body 40.

As described above, the mat material of the present invention has high heat insulating performance.
Therefore, in the exhaust gas purification device using the mat material of the present invention, the heat of the exhaust gas that has reached the exhaust gas treatment body is not easily released to the outside.

Hereinafter, the exhaust gas treatment body and the metal casing constituting the exhaust gas purification device 100 will be described.

(Exhaust gas treatment body)
FIG. 4A is a perspective view schematically showing an example of an exhaust gas treatment body constituting the exhaust gas purification device of the present invention. FIG. 4B is a cross-sectional view taken along the line AA of FIG. 4A.
As shown in FIGS. 4A and 4B, the exhaust gas treatment body 40 included in the exhaust gas purification device 100 is a columnar body in which a large number of cells 41 are arranged side by side in the longitudinal direction across the cell wall 42. is there.
Further, in the exhaust gas treatment body 40, one of the cells 41 is an exhaust gas filter (honeycomb filter) sealed with a sealing material 43.

As shown in FIG. 4B, the exhaust gas discharged from the internal combustion engine and flowing into the exhaust gas treatment body 40 (in FIG. 4B, the exhaust gas is indicated by G and the flow of the exhaust gas is indicated by an arrow) is the exhaust gas treatment body. It flows into one cell 41 opened on the exhaust gas inflow side end face of 40, and passes through the cell wall 42 separating the cells 41. At this time, PM in the exhaust gas is collected by the cell wall 42, and the exhaust gas is purified. The purified exhaust gas flows out from another cell 41 opened on the exhaust gas outflow side end face and is discharged to the outside.

The exhaust gas treatment body 40 shown in FIGS. 4A and 4B is a filter in which one end of the cell 41 is sealed with a sealing material 43, but the exhaust gas purification device of the present invention The exhaust gas treatment body constituting the above does not have to be sealed at the end of the cell. Such an exhaust gas treated body can be suitably used as a catalyst carrier.

The exhaust gas treatment body 40 may be made of a non-oxidized porous ceramic such as silicon carbide or silicon nitride, or may be made of an oxide porous ceramic such as sialon, alumina, corderite, or mullite. Of these, silicon carbide is desirable.

When the exhaust gas treatment body 40 is a silicon carbide 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 treatment body may be clogged immediately, while if the porosity exceeds 60%, the strength of the exhaust gas treatment body is reduced and it is easily destroyed. There is.

Further, it is desirable that the average pore diameter of the porous ceramic is 5 to 30 μm.
If the average pore diameter is less than 5 μm, PM may easily become clogged, while if the average pore diameter exceeds 30 μm, PM will pass through the pores and PM cannot be collected. This is because it may not be able to function as a filter.
The porosity and the pore diameter can be measured by a conventionally known method of measurement with a scanning electron microscope (SEM).

The cell density in the cross section of the exhaust gas treatment body 40 is not particularly limited, but the desirable lower limit is 31.0 cells / cm ² (200 cells / inch ² ), and the desirable upper limit is 93.0 cells / cm ² (600 cells / inch ² ). 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 treatment body 40 may be supported with a catalyst for purifying the exhaust gas, and as the catalyst to be supported, for example, a noble metal such as platinum, palladium, or rhodium is desirable, and among these, platinum is more preferable. Further, 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, PM can be easily burned and removed, and toxic exhaust gas can be purified.

(Metal casing)
The metal casing 50 has a substantially cylindrical shape.
The inner diameter of the metal casing 50 (the inner diameter of the portion accommodating the exhaust gas treatment body) is preferably slightly shorter than the diameter of the exhaust gas treatment body 40 around which the mat material 10 is wound.

The metal casing 50 is not particularly limited, but is preferably made of stainless steel.

Next, an exhaust pipe with a matte material provided with the matte material of the present invention, which is an example of how to use the matte material of the present invention, will be described.
The exhaust pipe with a mat material provided with the mat material of the present invention is also the exhaust pipe with a mat material of the present invention.

FIG. 5 is a cross-sectional view schematically showing an example of an exhaust pipe with a matte material provided with the matte material of the present invention.
As shown in FIG. 5, the exhaust pipe 200 with a mat material includes an exhaust pipe 60, a mat material 10 arranged so as to cover the exhaust pipe 60, and a metal cover 70 arranged outside the mat material 10. ..

Normally, when the exhaust gas (in FIG. 5, the exhaust gas is indicated by a symbol “G” and the gas flow is indicated by an arrow) passes through the exhaust pipe 60, the exhaust pipe 60 reaches about 380 ° C.

As described above, the mat material of the present invention has high heat insulating performance.
Therefore, in the exhaust gas purification device using the mat material of the present invention, the heat of the exhaust gas that has reached the exhaust gas treatment body is not easily released to the outside.

In the exhaust pipe 200 with a matte material, it is desirable that the exhaust pipe 60 is made of a metal such as stainless steel.
Further, in the exhaust pipe 200 with a matte material, it is desirable that the metal cover 70 is made of a metal such as stainless steel.

(Example)
Hereinafter, examples in which the present invention is disclosed more specifically will be shown. The present invention is not limited to these examples.

(Example 1-1)
(1) Inorganic Fiber Precursor Preparation Step A silica sol is blended with respect to the basic aluminum chloride aqueous solution so that the composition ratio of the inorganic fibers after firing is Al ₂ O ₃ : SiO ₂ = 72: 28 (weight ratio). Then, an appropriate amount of an organic polymer (polyvinyl alcohol) was added to prepare a mixed solution.
The obtained mixture was concentrated to prepare a mixture for spinning, and this mixture for spinning was spun by a blowing method (spinning atmosphere temperature: 120 ° C.) to prepare an alumina fiber precursor.
The average fiber diameter of the obtained alumina fiber precursor was 5.5 μm.

(2) Firing Step Subsequently, the alumina fiber precursor was compressed to prepare a continuous sheet having a width of 1254 mm and a thickness of 7.9 mm.
Needle punching treatment was performed so that the density was 23 pieces / cm ² .
Then, the sheet-like material was calcined at a maximum temperature of 1300 ° C. to convert the alumina fiber precursor into alumina fiber to obtain a sheet of an inorganic fiber aggregate.

(3) Infrared Reflector Applying Step Subsequently, a solution containing titanium oxide (average particle size: 8 μm, “Lutil Flower S” manufactured by Kinsei Matek Co., Ltd.) and an organic binder is prepared, and the solution is assembled with inorganic fibers. I attached it to my body. As a result, titanium oxide was attached to the inorganic fibers and then dried.
Through the above steps, the mat material according to Example 1-1, which is a needle punching mat material, was produced.
In the mat material according to Example 1, the ratio of the weight of the alumina fiber (inorganic fiber) to the weight of the titanium oxide (infrared reflector) was 100: 34.4.

(Example 1-2) to (Example 1-4) and (Comparative Example 1-1) to (Comparative Example 1-2)
Instead of titanium oxide, zirconium oxide (average particle size: 60 μm, “zirconia powder TZ-3Y-E” manufactured by Tosoh Corporation), zinc oxide (average particle size: 20 μm, “LPZINC-20” manufactured by Sakai Chemical Industry Co., Ltd.) Table 1 shows the ratio of the weight of alumina fiber (inorganic fiber) to the weight of infrared reflector or infrared absorber using silicon carbide (average particle size: 24 μm, “YB-600M” manufactured by Yakushima Denko Co., Ltd.). The mat materials according to Examples 1-2 to 1-4 were produced in the same manner as in Example 1-1 except for the ratios shown.
Further, the mat material according to Comparative Example 1-1 was produced in the same manner as in Example 1-1 except that titanium oxide was not used.
Further, instead of titanium oxide, aluminum oxide (average particle size: 0.03 μm, "DISPAL 11N7-80" manufactured by Sasol) is used, and the weight of alumina fiber (inorganic fiber) and the weight of aluminum oxide (inorganic particle). The mat material according to Comparative Example 1-2 was produced in the same manner as in Example 1-1 except that the ratio with and to was set to 100: 1.0.

The state of the inorganic fibers of the mat material according to Examples 1-1 to 1-4 and Comparative Example 1-2 was observed by SEM. The results are shown in FIGS. 6 (a) to 6 (e).
6 (a) to 6 (e) are SEM images of the inorganic fibers of the mat material according to Examples 1-1 to 1-4 and Comparative Example 1-2, respectively.

(Example 2-1)
(1) Mixture preparation step Silica sol is blended with respect to the basic aluminum chloride aqueous solution so that the composition ratio of the inorganic fibers after firing is Al ₂ O ₃ : SiO ₂ = 72: 28 (weight ratio). Further, an appropriate amount of an organic polymer (polyvinyl alcohol) was added to prepare a mixed solution.
The obtained mixture was concentrated to prepare a mixture for spinning, and this mixture for spinning was spun by a blowing method (spinning atmosphere temperature: 120 ° C.) to prepare an alumina fiber precursor.
The average fiber diameter of the obtained alumina fiber precursor was 5.5 μm.
Next, the obtained inorganic fiber precursor was compressed to prepare a continuous sheet-like product. After that, the sheet-like material was placed in a heating furnace and fired to produce an inorganic fiber aggregate.
Next, the inorganic fiber aggregate was wet-opened using a mixer to obtain alumina fibers.
Inorganic fiber, titanium oxide (average particle size: 8 μm, “Lutil Flower S” manufactured by Kinsei Matek Co., Ltd.), aluminum oxide (average particle size: 0.005 μm, “DISPERAL P2” manufactured by Sasol), and organic binder. Was mixed to prepare a mixed solution.

(2) Dehydration Step Next, a raw material sheet was prepared by pouring the mixed solution into a molding machine having a mesh for filtration formed on the bottom surface and then dehydrating the water in the mixed solution through the mesh.

(3) Heat and Pressurization Step Next, the raw material sheet was heated and pressurized at 175 ° C.
Through the above steps, a mat material according to Example 2-1 which is a papermaking mat material was produced.
In the mat material according to Example 2-1 the ratio of the weight of the alumina fiber (inorganic fiber) to the weight of the titanium oxide (infrared reflector) was 100: 34.4.

(Example 2-2) to (Example 2-4)
Instead of titanium oxide, zirconium oxide (average particle size: 60 μm, “zirconia powder TZ-3Y-E” manufactured by Tosoh Corporation), zinc oxide (average particle size: 20 μm, “LPZINC-20” manufactured by Sakai Chemical Industry Co., Ltd.) Table 2 shows the ratio of the weight of alumina fibers (inorganic fibers) to the weight of infrared reflectors or infrared absorbers using silicon carbide (average particle size: 24 μm, “YB-600M” manufactured by Yakushima Denko Co., Ltd.). The matte material according to Example 2-2-2 to Example 2-4 was produced in the same manner as in Example 2-1 except that the ratios shown were shown.

The state of the inorganic fibers of the mat material according to Examples 2-1 to 2-4 was observed by SEM. The results are shown in FIGS. 7 (a) to 7 (d).
7 (a) to 7 (d) are SEM images of the inorganic fibers of the mat material according to Examples 2-1 to 2-4, respectively.

(Insulation performance measurement test)
A test piece was cut out from a mat material having a thickness of 7 mm according to Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-2.
Next, a hot plate tester in which a spacer was arranged on the heat insulating block and a hot plate was arranged on the spacer was prepared.
Next, the test piece and the SUS plate having a thickness of 1.5 mm were sequentially stacked on the hot plate of the hot plate tester.
Next, the hot plate is heated to 200 ° C., 400 ° C., 600 ° C. and 800 ° C., and the temperature of the surface of the SUS plate 40 minutes after the temperature of the hot plate reaches each temperature is measured, and the SUS plate is measured. The surface temperature was used.
The results are shown in Table 3.

Further, the heat insulating performance measurement test was similarly carried out using the mat material according to Examples 2-1 to 2-4.
The results are shown in Table 4.

As shown in Tables 3 and 4, it was found that the mat materials according to Examples 1-1 to 1-4 and Examples 2-1 to 2-4 have high heat insulating performance.

(Measurement of hot 1000 cycle rear surface pressure)
The mat material according to Example 1-1 and the mat material according to Comparative Example 1-1 are arranged between the upper plate and the lower plate of the hot surface pressure measuring device, and the void bulk density (GBD) of the mat material is 0. A compression step of compressing to 30 g / cm ³ is performed, and after the compression step, the mat material is heated to an upper plate of 900 ° C. and a lower plate of 650 ° C. at a heating rate of 45 ° C./min in the compressed state. While maintaining the temperature at 900 ° C. for the upper plate and 650 ° C for the lower plate, a release step was performed to release the mat material so that the void bulk density (GBD) was 0.27 g / cm ^3, and after the release step, the mat was released. The material was recompressed so that the void bulk density (GBD) was 0.30 g / cm ^3, and then re-released so that the void bulk density (GBD) of the mat material was 0.27 g / cm ^3. A cycle step of repeating recompression and the rerelease 1000 times in total is performed, the load at the time of the final rerelease of the cycle step is measured, and the load is divided by the area of each mat material to obtain the surface pressure after 1000 cycles. (KPa) was measured. The results are shown in Table 5.

Further, in the compression step, the mat material is compressed so that the void bulk density (GBD) is 0.40 g / cm ^3, and in the release step, the void bulk density (GBD) of the mat material is 0.36 g / cm ^3. After the release step, the mat material is recompressed so that the void bulk density (GBD) is 0.40 g / cm ^3, and then the void bulk density (GBD) of the mat material is 0.36 g. The surface pressure (kPa) after 1000 cycles was measured by the same method as the above method except that the cycle step of re-releasing to / cm ³ and repeating the recompression and the re-release a total of 1000 times was performed. .. The results are shown in Table 5.

As shown in Table 5, it was found that the surface pressure of the mat material of the present invention after 1000 cycles was sufficiently high.
That is, it was found that the mat material of the present invention does not easily reduce the surface pressure even if the mat material is repeatedly compressed and released at a high temperature.
Therefore, when the mat material of the present invention is applied to an exhaust gas purification device or an exhaust pipe with a mat material, the exhaust gas purification device or the exhaust pipe with the mat material is exposed to vibration when the vehicle is driven. The material surface pressure does not easily decrease. Therefore, it is possible to prevent the exhaust gas treatment body from falling off from the casing and the mat material itself from falling off from the exhaust pipe with the mat material.

(Measurement of thermal conductivity)
The thermal conductivity (W / m · K) of titanium oxide having an average particle diameter of 0.7 μm, 2.8 μm and 8.0 μm at 25 ° C., 300 ° C., 500 ° C. and 800 ° C. was measured by the hot wire method.
The results are shown in Table 6.

As shown in Table 6, titanium oxide having a particle size of 1 to 10 μm does not have too high thermal conductivity. In particular, at 500 to 800 ° C., the thermal conductivity is lower than that of titanium oxide having a particle size of less than 1 μm.
It is considered that this is because the infrared reflectance of titanium oxide is high and the solid conductivity is not high.
Therefore, it has been found that it is desirable to use titanium oxide having a particle size of 1 to 10 μm as the infrared reflector.

10 Mat material 11 One end 11a Convex 12 The other end 12a Concave 15 Test piece 20 Hot plate tester 21 Insulation block 22 Spacer 23 Hot plate 30 SUS plate 40 Exhaust gas treatment body 41 Cell 42 Cell wall 43 Sealing Material 50 Metal casing 60 Exhaust pipe 70 Metal cover 100 Exhaust gas purification device 200 Exhaust pipe with mat material

Claims (11)

A mat material made of inorganic fibers
A mat material containing an infrared reflector and / or an infrared absorber having a particle size of 1 to 100 μm. The mat material is a needle punching mat material.
The mat material according to claim 1, wherein in the following heat insulation performance measurement test, the SUS surface temperature is 322 to 338 ° C. when the temperature of the hot plate is 800 ° C.
Insulation performance measurement test:
A test piece is cut out from a mat material with a thickness of 7 mm.
Prepare a hot plate tester with a spacer placed on the heat insulating block and a hot plate placed on the spacer.
On the hot plate of the hot plate tester, the test piece and the SUS plate with a thickness of 1.5 mm are stacked in order.
Heat the hot plate to the specified temperature and
The temperature of the surface of the SUS plate 40 minutes after the temperature of the hot plate reaches a predetermined temperature is measured and used as the SUS plate surface temperature. The mat material is a papermaking mat material.
The mat material according to claim 1, wherein in the following heat insulation performance measurement test, the SUS surface temperature is 294 to 327 ° C. when the hot plate temperature is 800 ° C.
Insulation performance measurement test:
A test piece is cut out from a mat material with a thickness of 7 mm.
Prepare a hot plate tester with a spacer placed on the heat insulating block and a hot plate placed on the spacer.
On the hot plate of the hot plate tester, the test piece and the SUS plate with a thickness of 1.5 mm are stacked in order.
Heat the hot plate to the specified temperature and
The temperature of the surface of the SUS plate 40 minutes after the temperature of the hot plate reaches a predetermined temperature is measured and used as the SUS plate surface temperature. The matte material according to any one of claims 1 to 3, wherein the infrared reflector is at least one of the group consisting of titanium oxide, iron oxide, zirconium oxide, zinc oxide and aluminum oxide. The matte material according to any one of claims 1 to 4, wherein the infrared absorber is made of silicon carbide. The ratio of the weight of the inorganic fiber to the total weight of the infrared reflector and the infrared absorber is as follows: weight of inorganic fiber: total weight of infrared reflector and infrared absorber = 100: 0.5 to 100: 200. The matte material according to any one of claims 1 to 5. The mat material according to any one of claims 1 to 6, wherein the mat material further contains inorganic particles having a particle diameter of less than 1 μm. The mat material according to any one of claims 1 to 7, wherein the mat material further includes an organic binder. The mat material according to any one of claims 1 to 8, which is a three-dimensional molded product. Exhaust gas treatment body and
A metal casing that houses the exhaust gas treatment body and
An exhaust gas purification device that is arranged between the exhaust gas treatment body and the metal casing and includes a mat material that holds the exhaust gas treatment body.
The exhaust gas purification device according to any one of claims 1 to 9, wherein the mat material is the mat material. Exhaust pipe and
A mat material arranged so as to cover the exhaust pipe and
An exhaust pipe with a mat material having a metal cover arranged on the outside of the mat material.
The exhaust pipe with a mat material, wherein the mat material is the mat material according to any one of claims 1 to 9.